use std::collections::linked_list::{LinkedList};
use std::collections::hash_map::{HashMap, Entry};
use std::collections::btree_map::{BTreeMap};
use std::collections::vec_deque::VecDeque;
use std::fs::{File};
use std::io::{self, Read, Write, Seek, SeekFrom};
use std::mem;
use std::fmt;
use operations::{Operation, InsertOperation, DeleteOperation, Advance, OperationInternal};
use ::{OTError, ErrorKind as Kind, Offset, Position};
use utils::{SequenceTransformer, SequenceSwapper, SequenceSplitter};
use rdiff::Diff;
use byteorder::{NetworkEndian, ByteOrder};

/// Process file change operations in such a way that they can be synchronized across sites
///
/// The engine keeps track of all transactions that have occurred so far, and makes sure that any operations that
/// happen locally or remotely will result in a consistent file on every site.
///
/// To use, simply pass through any local edits via `process_diffs()` (if they are recorded in a [`Diff`](https://dyule.github.io/rdiff/rdiff/struct.Diff.html))
/// or `process_transaction()` (If the operations are already stored in a [`TransactionSequence`](struct.TransactionSequence.html)) and pass any remote edits received into `integrate_remote()`.
///
/// See the module level documentation for an example.
#[derive(Clone)]
pub struct Engine {
    /// The unique ID for this site
    site_id: u32,

    /// The inserts for this site, stored in effect order
    inserts: LinkedList<InsertOperation>,

    /// The deletes for this site, stored in effect order
    deletes: LinkedList<DeleteOperation>,

}

/// Tracks the relationship between local timestamps and the timestamp on remote machines.
#[derive(Debug)]
pub struct TimeStamper {
    /// A mapping between the remote id of a transaction and its local timstamp
    time_mapping: HashMap<(u32, u32), u32>,

    /// The most recently used timestamp
    last_timestamp: Option<(u32, (u32, u32))>

}

/// Represents a sequence of transactions that can be performed on a file.
///
/// The operations are stored in the order they occur in the file, and each operation
/// assumes the previous operations have taken place.  Furthermore, the insertion operations are
/// assumed to take place prior to the deletion operations.
#[derive(Debug, Clone)]
pub struct TransactionSequence {
    /// Last time stamp assigned before the operations in this sequence were performed
    last_timestamp: Option<(u32, u32)>,

    /// The inserts for this sequence, stored in effect order
    pub inserts: LinkedList<InsertOperation>,

    /// The deletes for this sequence, stored in effect order
    pub deletes: LinkedList<DeleteOperation>,
}

// Public methods
impl Engine {
    #[inline]
    /// Creates a new engine for the given site id.  The id should be
    /// unique across all clients, and probably generated by the server
    pub fn new(site_id: u32) -> Engine {
        Engine {
            site_id: site_id,
            inserts: LinkedList::new(),
            deletes: LinkedList::new(),
        }
    }

    /// Convert the diffs we got from analyzing a file into a TransactionSequence
    /// we can send to another site for synchronization.
    pub fn process_diffs(&mut self, diff: Diff, stamper: &mut TimeStamper) -> (TransactionSequence, BTreeMap<u32, (u32, u32)>) {
        let current_timestamp = stamper.get_last_timestamp();
        let new_timestamp = stamper.stamp_local(self.site_id);
        let inserts = diff.inserts().map(|insert| {
            InsertOperation::new(
                insert.get_position()as Position,
                insert.get_data().clone(),
                new_timestamp,
                self.site_id,
            )
        }).collect();


        let deletes = diff.deletes().map(|delete| {
            DeleteOperation::new(
                delete.get_position() as Position,
                delete.get_length() as Position,
                new_timestamp
            )
        }).collect();
        let mut lookup = BTreeMap::new();
        lookup.insert(new_timestamp, (self.site_id, new_timestamp));
        let mut sequence = TransactionSequence::new(current_timestamp.map(|(_local, remote)| remote), inserts, deletes);
        self.process_transaction(&mut sequence);
        (sequence, lookup)
    }

    /// Integrates the sequence of operations given by `remote_sequence` into the local history.  The ordering
    /// properties of the local history will be maintained, and a sequence of operations that
    /// can be applied to the local state will be returned.
    pub fn integrate_remote(&mut self, remote_sequence: &mut TransactionSequence, lookup: &BTreeMap<u32, (u32, u32)>, stamper: &mut TimeStamper) -> Result<(), OTError> {

        //Get all the local inserts that have happened since the last sync with the remote site
        let local_concurrent_inserts = try!(self.get_concurrent_inserts(&remote_sequence, lookup, stamper));
        // Transform the remote inserts so that they account for the changes from the local inserts
        Engine::transform(&mut remote_sequence.inserts, &local_concurrent_inserts);

        // Save the inserts as they are before integrating the local deletes, since that will be
        // used later for integrating the remote deletes
        let mut transformed_remote_inserts = remote_sequence.inserts.clone();

        // Transform the remote inserts so that they account for the changes from the local deletes
        Engine::transform(&mut remote_sequence.inserts, &self.deletes);

        self.assign_timestamps(&mut transformed_remote_inserts, lookup, stamper);

        // Merge the transformed remote inserts with the local.  Note that we use the inserts that have not been
        // transformed by deletes, as the local inserts always preceded the deletes.
        Engine::merge_sequences(&mut self.inserts, &transformed_remote_inserts);

        // Adjust the local deletes with the remote inserts that have been merged into the local inserts
        Engine::transform(&mut self.deletes, &transformed_remote_inserts);
        // Transform the remote deletes with all of the local inserts that happened since the last sync
        let transformed_concurrent_inserts = try!(self.get_concurrent_inserts(&remote_sequence, lookup, stamper));

        Engine::transform(&mut remote_sequence.deletes, &transformed_concurrent_inserts);
        trace!("Sequence: {:?}", remote_sequence);

        // Transform the remote deletes with ALL of the local deletes.
        Engine::transform(&mut remote_sequence.deletes, &self.deletes);
        trace!("Sequence: {:?}", remote_sequence);

        self.assign_timestamps(&mut remote_sequence.deletes, &lookup, stamper);

        // Merge the remote deletes that have taken all the local operations into effect with the local deletes
         Engine::merge_sequences(&mut self.deletes, &mut remote_sequence.deletes);

         Ok(())

    }

    /// Processes a series of operations prior to being sent out to remote sites.  The operations must
    /// have been performed on the data after every operation in the local history, but no others.  The
    /// operations in the transaction must also be effect order, with the inserts preceding the deletes.
    pub fn process_transaction(&mut self, outgoing_sequence: &mut TransactionSequence) {

        Engine::split_by(&mut outgoing_sequence.deletes, &self.deletes);

        // Swap the execution order of the outgoing insert operations so that they happen before the local deletes
        Engine::swap(&mut outgoing_sequence.inserts, &mut self.deletes);

        let original_deletes = outgoing_sequence.deletes.clone();
        // Swap the execution order of the outgoing delete operations so they happen before the local deletes
        Engine::swap(&mut outgoing_sequence.deletes, &mut self.deletes.clone());

        // Record that we've performed the outgoing insertion operations
        Engine::merge_sequences(&mut self.inserts, &outgoing_sequence.inserts);

        // Record that we've performed the outgoing delete operations
        Engine::merge_sequences(&mut self.deletes, &original_deletes);

    }

    // /// Gets the state this engine saw last
    // pub fn get_last_state(&self) -> &Option<State> {
    //     &self.last_state
    // }

    /// Get all the operations since, but not including the given state
    pub fn get_operations_since(&self, remote_state: Option<(u32, u32)>, stamper: &TimeStamper) -> Result<TransactionSequence, OTError> {
        if let Some((remote_site_id, remote_timestamp)) = remote_state {
            let reference_time = try!(stamper.get_local_timestamp_for(remote_site_id, remote_timestamp)
                                               .ok_or(OTError::new(Kind::NoSuchState)));


            let inserts = self.inserts.iter().filter(|o| o.get_timestamp() > reference_time).cloned().collect();
            let deletes = self.deletes.iter().filter(|o| o.get_timestamp() > reference_time).cloned().collect();
            Ok(TransactionSequence::new(Some((remote_site_id, remote_timestamp)), inserts, deletes))
        } else {
            Ok(TransactionSequence::new(None, self.inserts.iter().cloned().collect(), self.deletes.iter().cloned().collect()))
        }
    }

    /// Compress this engine and write to `writer`.  The output can then be expanded
    /// back into an equivilent Engine using `expand_from()`
    pub fn compress_to<W: Write>(&self, writer: &mut W) -> io::Result<()> {
        let mut int_buf = [0;4];
        NetworkEndian::write_u32(&mut int_buf, self.inserts.len() as u32);
        try!(writer.write(&mut int_buf));
        for insert in self.inserts.iter() {
            try!(insert.compress_to(writer, true));
        }
        NetworkEndian::write_u32(&mut int_buf, self.deletes.len() as u32);
        try!(writer.write(&mut int_buf));
        for delete in self.deletes.iter() {
            try!(delete.compress_to(writer));
        }
        Ok(())
    }

    /// Expand this engine from previously compressed data in `reader`.  The data in reader
    /// should have been written using `compress_to()`
    pub fn expand_from<R: Read>(reader: &mut R, site_id: u32) -> io::Result<Engine> {
        trace!("Expanding engine");
        // let mut bool_buffer = [0;1];
        // trace!("Reading state");
        // try!(reader.read_exact(&mut bool_buffer));
        // let (state, time_stamp) = if bool_buffer[0] == 1 {
        //     let state = try!(State::expand_from(reader));
        //     let time_stamp = state.get_time() + 1;
        //     (Some(state), time_stamp)
        // } else {
        //     (None, 0)
        // };
        // trace!("State read: {:?}", state);
        let mut int_buf = [0;4];
        trace!("Reading insert length");
        try!(reader.read_exact(&mut int_buf));
        let insert_len = NetworkEndian::read_u32(&int_buf);
        trace!("Insert length was: {}", insert_len);
        let inserts = (0..insert_len).map(|_|InsertOperation::expand_from(reader, None).unwrap()).collect();
        trace!("Read inserts");
        trace!("Reading delete length");
        try!(reader.read_exact(&mut int_buf));
        let delete_len = NetworkEndian::read_u32(&int_buf);
        trace!("Delete length was: {}", delete_len);
        let deletes = (0..delete_len).map(|_|DeleteOperation::expand_from(reader).unwrap()).collect();
        trace!("Read deletes");

        Ok(Engine {
            site_id: site_id,
            inserts: inserts,
            deletes: deletes,
        })
    }
}

// Private methods
impl Engine {


    fn get_concurrent_inserts(&self, remote_sequence: &TransactionSequence, lookup: &BTreeMap<u32, (u32, u32)>, stamper: &TimeStamper) -> Result<LinkedList<InsertOperation>, OTError> {
        let mut tail_timestamp = None;
        for insert in remote_sequence.inserts.iter() {
            let timestamp = insert.get_timestamp();
            if let Some((local, _remote)) = tail_timestamp {

                if timestamp < local {
                    tail_timestamp = Some((timestamp, try!(lookup.get(&timestamp).ok_or(OTError::new(Kind::NoSuchState)))))
                }
            } else {
                tail_timestamp = Some((timestamp, try!(lookup.get(&timestamp).ok_or(OTError::new(Kind::NoSuchState)))))
            }
        }
        for delete in remote_sequence.deletes.iter() {
            let timestamp = delete.get_timestamp();
            if let Some((local, _remote)) = tail_timestamp {

                if timestamp < local {
                    tail_timestamp = Some((timestamp, try!(lookup.get(&timestamp).ok_or(OTError::new(Kind::NoSuchState)))))
                }
            } else {
                tail_timestamp = Some((timestamp, try!(lookup.get(&timestamp).ok_or(OTError::new(Kind::NoSuchState)))))
            }
        }
        let tail_timestamp = tail_timestamp.map(|(_, &(site_id, timestamp))| stamper.get_local_timestamp_for(site_id, timestamp).unwrap());
        trace!("Getting inserts after {:?} and before {:?}", remote_sequence.last_timestamp, tail_timestamp);
        if let Some((remote_site_id, remote_timestamp)) = remote_sequence.last_timestamp {
            let reference_time = try!(stamper.get_local_timestamp_for(remote_site_id, remote_timestamp)
                                               .ok_or(OTError::new(Kind::NoSuchState)));
            Ok(self.inserts.iter().filter(|o|
                if let Some(tail) = tail_timestamp {
                    o.get_timestamp() > reference_time && o.get_timestamp() < tail
                } else {
                    o.get_timestamp() > reference_time
                }).cloned().collect())
        } else {
            Ok(self.inserts.iter().filter(|o|
                if let Some(tail) = tail_timestamp {
                    o.get_timestamp() < tail
                } else {
                    true
                }).cloned().collect())
        }

    }

    fn assign_timestamps<O: Operation>(&mut self, sequence: &mut LinkedList<O>, timestamp_lookup: &BTreeMap<u32, (u32, u32)>, stamper: &mut TimeStamper) {
        trace!("Assigning time_stamps to {:?}", sequence);
        for o in sequence.iter_mut() {
            // TODO add better error handling here.
            let &(remote_site_id, remote_timestamp) = timestamp_lookup.get(&o.get_timestamp()).unwrap();
            let local_timestamp = stamper.stamp_remote(remote_site_id, remote_timestamp);
            o.set_timestamp(local_timestamp)
        }
        trace!("Timestamps assigned to {:?}", sequence);
    }

    fn transform<O1: OperationInternal, O2: OperationInternal>(incoming_sequence: &mut LinkedList<O1>, existing_sequence: &LinkedList<O2>)  {
        trace!("Transforming {:?} by {:?}", incoming_sequence, existing_sequence);
        let mut incoming_iter = incoming_sequence.iter_mut();
        let mut existing_iter = existing_sequence.iter();
        let mut saved_op = None;
        let mut incoming_op = incoming_iter.next();
        let mut existing_op = existing_iter.next();
        let mut transformer = SequenceTransformer::new();
        loop {

            let advance_action = if let Some(existing_op) = existing_op {
                 if let Some(ref mut incoming_op) = incoming_op {
                     transformer.transform_operations::<O1, O2>(incoming_op, existing_op)
                } else {
                    if let Some(ref mut incoming_op) = saved_op{
                        transformer.transform_operations::<O1, O2>(incoming_op, existing_op)
                    } else {
                        Advance::Existing
                    }
                }
            } else{
                if let Some(ref mut incoming_op) = incoming_op {
                    transformer.transform_single::<O1>(incoming_op);
                    Advance::Incoming
                } else if let Some(ref mut incoming_op) = saved_op{
                    transformer.transform_single::<O1>(incoming_op);
                    Advance::Incoming
                } else {
                    break;
                }
            };
            match advance_action {
                Advance::Incoming => {
                    if saved_op.is_some() {
                        incoming_iter.insert_next(mem::replace(&mut saved_op, None).unwrap())
                    }
                    incoming_op = incoming_iter.next();
                },
                Advance::Existing => {
                    existing_op = existing_iter.next();
                },
                Advance::Neither(new_op) => {
                    if saved_op.is_some() {
                        incoming_iter.insert_next(mem::replace(&mut saved_op, Some(new_op)).unwrap())
                    } else {
                        mem::replace(&mut saved_op, Some(new_op));
                    }
                    incoming_op = None;
                }
            }


        }
    }

    fn swap<O: OperationInternal>(incoming_sequence: &mut LinkedList<O>, existing_sequence: &mut LinkedList<DeleteOperation>)  {
        trace!("Swapping {:?} and {:?}", incoming_sequence, existing_sequence);
        {
            let mut incoming_iter = incoming_sequence.iter_mut();
            let mut existing_iter = existing_sequence.iter_mut();
            let mut incoming_op = incoming_iter.next();
            let mut existing_op = existing_iter.next();
            let mut swapper = SequenceSwapper::new();
            loop {

                let advance_incoming = if let Some(ref mut existing_op) = existing_op {
                     if let Some(ref mut incoming_op) = incoming_op {
                         swapper.swap_operations::<O>(incoming_op, existing_op)
                    } else {
                        swapper.swap_existing(existing_op);
                        false
                    }
                } else{
                    if let Some(ref mut incoming_op) = incoming_op {
                        swapper.swap_single::<O>(incoming_op);
                        true
                    }  else {
                        break;
                    }
                };
                if advance_incoming {
                    incoming_op = incoming_iter.next();
                } else {
                    existing_op = existing_iter.next();
                }

            }
        }
        trace!("After swap: {:?} and {:?}", incoming_sequence, existing_sequence);
    }



    fn split_by(incoming_sequence: &mut LinkedList<DeleteOperation>, existing_sequence: &LinkedList<DeleteOperation>)  {
        trace!("splitting {:?} by {:?}", incoming_sequence, existing_sequence);
        let mut incoming_iter = incoming_sequence.iter_mut();
        let mut existing_iter = existing_sequence.iter();
        let mut saved_op = None;
        let mut incoming_op = incoming_iter.next();
        let mut existing_op = existing_iter.next();
        let mut splitter = SequenceSplitter::new();
        loop {

            let advance_action = if let Some(existing_op) = existing_op {
                 if let Some(ref mut incoming_op) = incoming_op {
                     splitter.split_operations(incoming_op, existing_op)
                } else if let Some(ref mut incoming_op) = saved_op {
                    splitter.split_operations(incoming_op, existing_op)
               } else {
                    break
                }
            } else{
                if let Some(_) = saved_op {
                    Advance::Incoming
               } else {
                   break
               }
            };
            match advance_action {
                Advance::Incoming => {
                    if saved_op.is_some() {
                        incoming_iter.insert_next(mem::replace(&mut saved_op, None).unwrap())
                    }
                    incoming_op = incoming_iter.next();
                },
                Advance::Existing => {
                    existing_op = existing_iter.next();
                },
                Advance::Neither(new_op) => {
                    if saved_op.is_some() {
                        incoming_iter.insert_next(mem::replace(&mut saved_op, Some(new_op)).unwrap())
                    } else {
                        mem::replace(&mut saved_op, Some(new_op));
                    }
                    incoming_op = None;
                }
            }


        }
    }



    fn merge_sequences<O: OperationInternal>(seq1: &mut LinkedList<O>, seq2: &LinkedList<O>) {
        fn something_less<O: OperationInternal>(mut a: Option<&mut O>, b: &O, offset: Offset) -> bool {
            trace!("Comparing {:?} and {:?} with offset {}", a, b, offset);
            match a {
                Some(ref mut a) => {
                    if a.get_position() as Offset <= b.get_position() as Offset - offset {
                        (**a).update_position_by(offset);
                        true
                    } else {
                        false
                    }

                }, None => {
                    false
                }
            }
        }
        trace!("Merging sequence {:?} into {:?}", seq2, seq1);
        let mut seq1_iter = seq1.iter_mut();
        let mut seq2_iter = seq2.iter();
        let mut offset = 0;
        while let Some(elem2) = seq2_iter.next() {
            while something_less(seq1_iter.peek_next(), &elem2, offset) {
                seq1_iter.next();
            }
            offset += elem2.get_increment();
            seq1_iter.insert_next(elem2.clone());
        }
        while seq1_iter.peek_next().is_some() {
            seq1_iter.next().unwrap().update_position_by(offset);
        }
    }
}

impl fmt::Debug for Engine {
    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
        try!(writeln!(f, "Site: {}", self.site_id));
        try!(writeln!(f, "Inserts: {:?}", self.inserts));
        writeln!(f, "Deletes: {:?}", self.deletes)
    }
}

impl TimeStamper {
    /// Create a new `TimeStamper`, with no stamps yet assigned
    pub fn new() -> TimeStamper {
        TimeStamper {
            time_mapping: HashMap::new(),
            last_timestamp: None
        }
    }

    /// Stamp a remote operation corrsponding to the given site_id and remtoe timestamp
    /// with a local timestamp.  If this remote id has never been stamped before, then
    /// assign it a new timestamp, sequentially after the previous one.  If it has, the
    /// previously assigned timestamp is returned
    pub fn stamp_remote(&mut self, site_id: u32, remote_timestamp: u32) -> u32 {
        match self.time_mapping.entry((site_id, remote_timestamp)) {
            Entry::Occupied(entry) => {
                *entry.get()
            }, Entry::Vacant(entry) => {
                let time_stamp =  self.last_timestamp.map_or(0, |(local, _)| local + 1);
                entry.insert(time_stamp);
                self.last_timestamp = Some((time_stamp, (site_id, remote_timestamp)));
                time_stamp
            }
        }
    }

    /// Stamp a local operation.  This will always create a new timestamp
    pub fn stamp_local(&mut self, site_id: u32) -> u32 {
        let time_stamp =  self.last_timestamp.map_or(0, |(local, _)| local + 1);
        self.time_mapping.insert((site_id, time_stamp), time_stamp);
        self.last_timestamp = Some((time_stamp, (site_id, time_stamp)));
        time_stamp
    }

    /// Gets the local timestamp corresponding to a given remote site_id and remote timestamp
    pub fn get_local_timestamp_for(&self, remote_site_id: u32, remote_timestamp: u32) -> Option<u32> {
        self.time_mapping.get(&(remote_site_id, remote_timestamp)).map(|t| {*t})
    }

    /// Gets a mapping of timestamps since the given remote site_id and remote timesamp, ordered sequentially, or none if the remote timestamp isn't in the lookup
    pub fn get_timestamps_since(&self, remote: Option<(u32, u32)>) -> Option<BTreeMap<u32, (u32, u32)>> {
        if let Some((remote_site_id, remote_timestamp)) = remote {
            self.get_local_timestamp_for(remote_site_id, remote_timestamp).map(|local_timestamp| {
                self.time_mapping.iter().filter(|&(_, saved_timestamp)| {
                    *saved_timestamp > local_timestamp
                }).map(|(&(a, b), c)|{(*c, (a, b))}).collect()
            })
        } else {
            Some(self.time_mapping.iter().map(|(&(a, b), c)|{(*c, (a, b))}).collect())
        }
    }

    #[inline]
    /// Gets the most recent timestamp this stamper has assigned, or None if it has not yet assigned a timestamp.
    /// The timestamp contains both the local and remote timestamps
    pub fn get_last_timestamp(&self) -> Option<(u32, (u32, u32))> {
        self.last_timestamp
    }

    /// Compresses this `TimeStamper` to an output source.  This can then be
    /// expanded again using `expand_from`
    pub fn compress_to<W: io::Write>(&self, writer: &mut W) -> io::Result<()> {
        let mut int_buf = [0;4];
        NetworkEndian::write_u32(&mut int_buf, self.time_mapping.len() as u32);
        try!(writer.write(&int_buf));
        for (&(site_id, remote), local) in self.time_mapping.iter() {
            NetworkEndian::write_u32(&mut int_buf, site_id);
            try!(writer.write(&int_buf));
            NetworkEndian::write_u32(&mut int_buf, remote);
            try!(writer.write(&int_buf));
            NetworkEndian::write_u32(&mut int_buf, *local);
            try!(writer.write(&int_buf));
        }
        Ok(())
    }

    /// Expands a `TimeStamper` from an input source that was previous written to
    /// by `compress_to()`
    pub fn expand_from<R: io::Read>(reader: &mut R) -> io::Result<TimeStamper> {
        let mut int_buf = [0;4];
        try!(reader.read_exact(&mut int_buf));
        let map_len = NetworkEndian::read_u32(&int_buf) as usize;
        let mut time_mapping = HashMap::with_capacity(map_len);
        let mut biggest = None;
        for _ in 0..map_len {
            try!(reader.read_exact(&mut int_buf));
            let site_id = NetworkEndian::read_u32(&int_buf);
            try!(reader.read_exact(&mut int_buf));
            let remote = NetworkEndian::read_u32(&int_buf);
            try!(reader.read_exact(&mut int_buf));
            let local = NetworkEndian::read_u32(&int_buf);
            let bigger = match biggest {
                Some((biggest_local, _)) => {
                     local > biggest_local
                }, None => {
                    true
                }
            };
            if bigger {
                biggest = Some((local, (site_id, remote)));
            }
            time_mapping.insert((site_id, remote), local);
        }
        Ok(TimeStamper {
            time_mapping: time_mapping,
            last_timestamp: biggest
        })
    }
}

impl TransactionSequence {

    /// Construct a new `TransactionSequence` from the given operations and metadata
    /// `last_timestamp` is the last stamp that was assigned before this operation was created
    /// `timestamp_lookup` is a mapping between local timestamps and their remote counterparts
    #[inline]
    pub fn new(last_timestamp: Option<(u32, u32)>, inserts: LinkedList<InsertOperation>, deletes: LinkedList<DeleteOperation>) -> TransactionSequence {
        TransactionSequence {
            last_timestamp: last_timestamp,
            inserts: inserts,
            deletes: deletes
        }
    }

//Words words words. More words! Hey Words!words!s words
//Got the stuff! And this other thing! Now how about this?

    /// Apply the operations in this sequence to a file.  This should not be called until after
    /// the sequence has been integrated via [`Engine::integrate_remote`](struct.Engine.html#method.integrate_remote)
    /// The file must have been opened on both read and write mode (see [OpenOptions](https://doc.rust-lang.org/nightly/std/fs/struct.OpenOptions.html)).
    pub fn apply(&self, file: &mut File) -> io::Result<()> {
        use std::slice;
        try!(file.seek(SeekFrom::Start(0)));
        // TODO try to find the size of the file?
        // XXX In future, we want this to read in chunks of the file at a time.
        let mut file_bytes = Vec::new();

        try!(file.read_to_end(&mut file_bytes));
        try!(file.seek(SeekFrom::Start(0)));
        try!(file.set_len(0));
        let mut insert_stack:VecDeque<slice::Iter<u8>> = VecDeque::new();
        let mut current_delete = 0;
        insert_stack.push_front(file_bytes.iter());
        let mut inserts = self.inserts.iter().peekable();
        let mut deletes = self.deletes.iter().peekable();
        let mut insert_index = 0;
        let mut delete_index = 0;
        while !insert_stack.is_empty() {
            let should_insert = if let Some(next_insert) = inserts.peek() {
                if next_insert.get_position() == insert_index {
                    true
                } else {
                    false
                }
            } else {
                false
            };
            if should_insert {
                insert_stack.push_front(inserts.next().unwrap().get_value().iter());
            } else {
                let should_delete = if let Some(delete) = deletes.peek() {
                    if delete.get_position() == delete_index {
                        true
                    } else {
                        false
                    }
                } else {
                    false
                };
                if should_delete {
                    current_delete += deletes.next().unwrap().get_length();
                } else {
                    let next = insert_stack.front_mut().unwrap().next();
                    if let Some(next) = next {
                        if current_delete == 0 {
                            try!(file.write(&[*next]));
                            insert_index += 1;
                            delete_index += 1;
                        } else {
                            current_delete -= 1;
                            insert_index += 1;
                        }
                    } else {
                        insert_stack.pop_front();
                    }
                }
            }
        }
        Ok(())
        // for insert in self.inserts.iter() {
        //     while index < insert.get_position() {
        //         new_bytes.push(try!(old_bytes.next().unwrap()).clone());
        //         index += 1;
        //     }
        //     new_bytes.extend_from_slice(insert.get_value());
        //     index += insert.get_value().len() as Position;
        // }
        // while let Some(byte) = old_bytes.next() {
        //     new_bytes.push(try!(byte));
        // }
        // let old_bytes = mem::replace(&mut new_bytes, Vec::new());
        // let mut old_bytes = old_bytes.into_iter();
        // index = 0;
        // for delete in self.deletes.iter() {
        //     while index < delete.get_position() {
        //         new_bytes.push(match old_bytes.next(){
        //             Some(b) => b,
        //             None => {
        //                 panic!("Could not read byte {}", index);
        //             }
        //         });
        //         index += 1;
        //     }
        //     for _ in 0..delete.get_length() {
        //         old_bytes.next();
        //     }
        // }
        // while let Some(byte) = old_bytes.next() {
        //     new_bytes.push(byte);
        // }
        //
        // try!(file.seek(SeekFrom::Start(0)));
        // try!(file.set_len(new_bytes.len() as u64));
        // file.write_all(new_bytes.as_slice())
    }

    /// Compress this transaction and write to `writer`.  The output can then be expanded
    /// back into an equivilent Transaction using `expand_from()`
    pub fn compress_to<W: Write>(&self, writer: &mut W) -> io::Result<()> {
        let mut int_buf = [0;4];
        if let Some((site_id, timestamp)) = self.last_timestamp {
            try!(writer.write(&[1]));
            NetworkEndian::write_u32(&mut int_buf, site_id);
            try!(writer.write(&mut int_buf));
            NetworkEndian::write_u32(&mut int_buf, timestamp);
            try!(writer.write(&mut int_buf));
        } else {
            try!(writer.write(&[0]));
        }

        NetworkEndian::write_u32(&mut int_buf, self.inserts.len() as u32);
        try!(writer.write(&mut int_buf));
        for insert in self.inserts.iter() {
            try!(insert.compress_to(writer, false));
        }
        NetworkEndian::write_u32(&mut int_buf, self.deletes.len() as u32);
        try!(writer.write(&mut int_buf));
        for delete in self.deletes.iter() {
            try!(delete.compress_to(writer));
        }
        Ok(())
    }

    /// Expand this transaction from previously compressed data in `reader`.  The data in reader
    /// should have been written using `compress_to()`
    pub fn expand_from<R: Read>(reader: &mut R, timestamp_lookup: Option<&BTreeMap<u32, (u32, u32)>>) -> io::Result<TransactionSequence> {
        trace!("Reading transaction");
        let mut bool_buffer = [0;1];
        let mut int_buf = [0;4];
        try!(reader.read_exact(&mut bool_buffer));
        let last_timestamp = if bool_buffer[0] == 1 {
            trace!("Reading State");
            try!(reader.read_exact(&mut int_buf));
            let site_id = NetworkEndian::read_u32(&int_buf);
            try!(reader.read_exact(&mut int_buf));
            let time_stamp = NetworkEndian::read_u32(&int_buf);
            Some((site_id, time_stamp))
        } else {
            trace!("No state");
            None
        };

        let mut int_buf = [0;4];
        trace!("Reading insert length");
        try!(reader.read_exact(&mut int_buf));
        let insert_len = NetworkEndian::read_u32(&int_buf);
        trace!("Insert length was: {}", insert_len);
        let mut inserts = LinkedList::new();
        for _ in 0..insert_len {
            inserts.push_back(try!(InsertOperation::expand_from(reader, timestamp_lookup)))
        }
        trace!("Read inserts");
        trace!("Reading delete length");
        try!(reader.read_exact(&mut int_buf));
        let delete_len = NetworkEndian::read_u32(&int_buf);
        trace!("Delete length was: {}", delete_len);
        let mut deletes = LinkedList::new();
        for _ in 0..delete_len {
            deletes.push_back(try!(DeleteOperation::expand_from(reader)));
        }
        trace!("Read deletes");
        Ok(TransactionSequence {
            last_timestamp: last_timestamp,
            inserts: inserts,
            deletes: deletes
        })
    }
}


#[cfg(test)]
mod tests {
    use super::{Engine, TransactionSequence, TimeStamper};
    use std::collections::{LinkedList, BTreeMap};
    use operations::{InsertOperation, DeleteOperation, Operation};
    use ::{Position};
    extern crate env_logger;

    macro_rules! create_list {
        ( $( $x:expr ),* ) => {
            {
                vec![$($x,)*].into_iter().collect::<LinkedList<_> >()
            }
        };
    }

    fn generate_insert_list(operation_details: Vec<(Position, &'static str)>, site_id: u32, starting_time: u32) -> LinkedList<InsertOperation> {
        operation_details.iter().map(|&(position, value)| {
            InsertOperation::new(position, value.bytes().collect(), starting_time, site_id)
        }).collect()
    }

    fn generate_delete_list(operation_details: Vec<(Position, Position)>, site_id: u32, starting_time: u32) -> LinkedList<DeleteOperation> {
        operation_details.iter().map(|&(position, length)| {
            DeleteOperation::new(position, length, starting_time)
        }).collect()
    }

    fn to_insert_tuple_vec<'a>(list: &'a LinkedList<InsertOperation>) -> Vec<(Position, &'a str)> {
        use std::str;
        list.iter().map(|op| {
            (op.get_position(), unsafe {str::from_utf8_unchecked(&op.get_value())})
        }).collect()
    }

    fn to_delete_tuple_vec<'a>(list: &'a LinkedList<DeleteOperation>) -> Vec<(Position, Position)> {
        list.iter().map(|op| {
            (op.get_position(), op.get_length())
        }).collect()
    }


    #[test]
    fn test_transform_insert_insert() {
        // Starting with the buffer "The quick brown fox"
        let mut sequence1 = generate_insert_list(vec![
            // Add an "ee" after "the"
            (3, "ee"),
            // Add another "k" on the end of "quick"
            (11, "k"),
            // Add "wnwnwn" to the end of "brown"
            (18, "wnwnwn"),
            // Add "xx!" to the end of "fox"
            (28, "xx!")
        ], 2, 0);
        // After sequence1 is applied, we would have "Theee quickk brownwnwnwn foxxx!"
        let sequence2 = generate_insert_list(vec![
            // insert "very " after "the"
            (4, "very "),
            // insert "ly" after "quick"
            (14, "ly"),
            // insert "u" after the 'o' in "brown"
            (20, "u"),
        ], 1, 4);
        Engine::transform(&mut sequence1, &sequence2);
        // After sequence2 is applied, we would have "The very quickly brouwn fox"
        assert_eq!(to_insert_tuple_vec(&sequence1), vec![
            // Add an "ee" after "the"
            (3, "ee"),
            // Add another "k" on the end of "quickly"
            (18, "k"),
            // Add "wnwnwn" to the end of "brouwn"
            (26, "wnwnwn"),
            // Add "xx!" to the end of "fox"
            (36, "xx!"),
        ]);
        // If sequence 2 is applied after sequence 1, we would have "Theee very quicklyk brouwnwnwnwn foxxx!"
    }

    #[test]
    fn test_transform_delete_insert(){
        // Starting with the buffer "The very quickly brouwn fox"
        let mut sequence1 = generate_delete_list(vec![
            // delete the "e" from "the"
            (2, 1),
            // delete the "e" from "very"
            (4, 1),
            // delete the "ui" from "quickly"
            (8, 2),
            // delete the "ou" from "brouwn"
            (15, 2),
            // delete the "o" from "fox"
            (19, 1),
        ], 1, 0);
        // after sequence1 is applied, we would have "Th vry qckly brwn fx"
        let sequence2 = generate_insert_list(vec![
            // Add an "ee" after "the"
            (3, "ee"),
            // Add another "k" on the end of "quickly"
            (18, "k"),
            // Add "wnwnwn" to the end of "brouwn"
            (26, "wnwnwn"),
            // Add "xx!" to the end of "fox"
            (36, "xx!"),
        ], 2, 5);
        // After sequence2 is applied, we will have "Theee very quicklyk brouwnwnwnwn foxxx!"
        Engine::transform(&mut sequence1, &sequence2);
        assert_eq!(to_delete_tuple_vec(&sequence1), vec![
            // delete the first "e" from "theee"
            (2, 1),
            // delete the "e" from "very"
            (6, 1),
            // delete the "ui" from "quicklyk"
            (10, 2),
            // delete the "ou" from "brouwnwnwnwn"
            (18, 2),
            // delete the "o" from "foxxx!"
            (28, 1),
        ]);
        // After running sequence1 then sequence2, we get "Thee vry qcklyk brwnwnwnwn fxxx!"
    }
    #[test]
    fn test_transform_delete_delete() {
      // Starting with buffer "The quick brown fox jumped over the lazy dog"
      let sequence1 =  generate_delete_list(vec![
          // Delete "quick bro"
          (4, 9),
          // Delete "ed over"
          (15, 7),
          // Delete "laz"
          (20, 3),
      ], 2, 0);
      // After sequence1 is applied, we will have "The wn fox jump the y dog"
      let mut sequence2 =  generate_delete_list(vec![
          // Delete "he qu"
          (1, 5),
          // Delete "ck"
          (2, 2),
          // Delete "rown"
          (4, 4),
          // Delete "the lazy dog"
          (21, 12),
      ], 1, 3);
      // After sequence2 is applied, we will have "Ti b fox jumped over "
      let mut seq1_prime = sequence1.clone();
      Engine::transform(&mut seq1_prime, &sequence2);
      assert_eq!(to_delete_tuple_vec(&seq1_prime), vec![
          // Delete "i"
          (1, 1),
          // Delete " b"
          (1, 2),
          // Delete "ed over"
          (10, 7),
          // Delete "" (was "laz")
          (11, 0),
      ]);
      // After both are applied we will have "T fox jump "
      Engine::transform(&mut sequence2, &sequence1);
      assert_eq!(to_delete_tuple_vec(&sequence2), vec![
          // Delete "he "
          (1, 3),
          // Delete ""
          (1, 0),
          // Delete "wn"
          (1, 2),
          // Delete "the "
          (11, 4),
          // Delete "y dog"
          (11, 5),
      ]);
  }

  #[test]
  fn test_transform_delete_delete_with_0_length_deletes() {
      // Starting with buffer "The quick brown fox jumped over the lazy dog"
      let sequence1 = generate_delete_list(vec![
          // Delete "h"
          (1, 1),
          // Delete "" after "T"
          (1, 0),
          // Delete "ck "
          (6, 3),
          // Delete "" after "n"
          (11, 0),
      ], 2, 0);
      // After sequence1 is applied, we will have "Te quibrown fox jumped over the lazy dog"
      let mut sequence2 = generate_delete_list(vec![
          // Delete "e"
          (2, 1),
          // Delete "c"
          (6, 1),
          // Delete "ow"
          (10, 2),
          // Delete "mp"
          (18, 2),
          // Detete " " after "the
          (29, 1),
      ], 1, 4);
      // After sequence2 is applied, we will have "Th quik brn fox jued over thelazy dog"
      Engine::transform(&mut sequence2, &sequence1);
      assert_eq!(to_delete_tuple_vec(&sequence2), vec![
          // Delete "e"
          (1, 1),
          // Delete "" (was delete "c")
          (5, 0),
          // Delete "ow"
          (7, 2),
          // Delete "mp"
          (15, 2),
          // Delete " " after "the"
          (26, 1),
      ]);
      // After both have been applied, we will have "T quibrn fox jued over thelazy dog"
  }

  #[test]
  fn test_transform_delete_delete_simple() {
      // starting with buffer "The quick brown fox jumped over the lazy dog"
      let sequence1 =  generate_delete_list(vec![
          // Delete "The"
          (0, 3),
          // Delete "brown"
          (7, 5),
          // Delete "jumped"
          (12, 6),
          // Delete "the"
          (18, 3),
          // Delete "dog"
          (24, 3),
      ], 1, 0);
      // After these operations run, we will have " quick  fox  over  lazy "
      let mut sequence2 =  generate_delete_list(vec![
          // Delete "quick"
          (4, 5),
          // Delete "fox"
          (11, 3),
          // Delete "over"
          (19, 4),
          // Delete "lazy"
          (24, 4),
      ], 2, 5);
      // After these operations, we will have "The  brown  jumped  the  dog"
      let mut seq1_prime = sequence1.clone();
      Engine::transform(&mut seq1_prime, &sequence2);
      assert_eq!(to_delete_tuple_vec(&seq1_prime), vec![
          // Delete "The"
          (0, 3),
          // Delete "brown"
          (2, 5),
          // Delete "jumped"
          (4, 6),
          // Delete "the"
          (6, 3),
          // Delete "dog"
          (8, 3),
      ]);

      Engine::transform(&mut sequence2, &sequence1);
      assert_eq!(to_delete_tuple_vec(&sequence2), vec![
          // Delete "quick"
          (1, 5),
          // Delete "fox"
          (3, 3),
          // Delete "over"
          (5, 4),
          // Delete "lazy"
          (7, 4),
      ]);
  }

  #[test]
  fn test_split() {
      // starting with buffer "The quick brown fox jumped over the lazy dog"
      let mut sequence1 = generate_delete_list(vec![
          // Delete "The  brown"
          (0, 10),
          // Delete "jumped  the  dog"
          (2, 16),
      ], 1, 0);
      // After these operations run, we will have " "
      let mut sequence2 = generate_delete_list(vec![
          // Delete "quick"
          (4, 5),
          // Delete "fox"
          (11, 3),
          // Delete "over"
          (19, 4),
          // Delete "lazy"
          (24, 4),
      ], 2, 2);
      // After these operations, we will have "The  brown  jumped  the  dog"
      Engine::split_by(&mut sequence1, &sequence2);
      assert_eq!(to_delete_tuple_vec(&sequence1), vec![
        (0, 4),
        (0, 6),
        (2, 7),
        (2, 5),
        (2, 4)
      ]);
  }

  #[test]
  fn test_swap_delete_insert(){
      // Starting with the buffer "The quick brown fox"
        let mut sequence1 = generate_insert_list(vec![
            // insert "very " after "t "
            (2, "very "),
            // insert "ly" after "quick"
            (12, "ly"),
            // insert "u" before the 'w'  in "wn"
            (15, "u"),
        ], 1, 0);
        // After this runs, we will have "T very quickly uwn ox"
        let mut sequence2 = generate_delete_list(vec![
            // Delete the "he" from "the"
            (1, 2),
            // Delete "bro" from "brown"
            (8, 3),
            // Delete "f" from "fox"
            (11, 1)
        ], 2, 3);
      // After this runs, we will have  "T quick wn ox"
      Engine::swap(&mut sequence1, &mut sequence2);
      assert_eq!(to_insert_tuple_vec(&sequence1), vec![
      // insert "very " after "the "
      (4, "very "),
      // insert "ly" after "quick"
      (14, "ly"),
      // insert "u" before the 'w'  in "wn"
      (20, "u"),
      ]);
      // After this runs, we will have "The very quickly brouwn fox"
      assert_eq!(to_delete_tuple_vec(&sequence2), vec![
      // Delete the "he" from "the"
      (1, 2),
      // Delete "bro" from "brown"
      (15, 3),
      // Delete "f" from "fox"
      (19, 1)
      ]);
      // After this runs, we will have "T very quickly uwn ox"
  }

  #[test]
  fn test_swap_delete_delete(){
          // starting with buffer "The quick brown fox jumped over the lazy dog"
          let mut sequence1 = generate_delete_list(vec![
              // Delete "The"
              (0, 3),
              // Delete "brown"
              (2, 5),
              // Delete "jumped"
              (4, 6),
              // Delete "the"
              (6, 3),
              // Delete "dog"
              (8, 3),
          ], 1, 0);
          // After these operations run, we will have " quick  fox  over  lazy "
          let mut sequence2 = generate_delete_list(vec![
              // Delete "quick"
              (4, 5),
              // Delete "fox"
              (11, 3),
              // Delete "over"
              (19, 4),
              // Delete "lazy"
              (24, 4),
          ], 2, 5);
          // After these operations, we will have "The  brown  jumped  the  dog"

          Engine::swap(&mut sequence1, &mut sequence2);
          assert_eq!(to_delete_tuple_vec(&sequence1), vec![
              // Delete "The"
              (0, 3),
              // Delete "brown"
              (7, 5),
              // Delete "jumped"
              (12, 6),
              // Delete "the"
              (18, 3),
              // Delete "dog"
              (24, 3),
          ]);

          assert_eq!(to_delete_tuple_vec(&sequence2), vec![
              // Delete "quick"
              (1, 5),
              // Delete "fox"
              (3, 3),
              // Delete "over"
              (5, 4),
              // Delete "lazy"
              (7, 4),
          ]);
      }
      #[test]
      fn test_swap_delete_delete_with_overlap() {
          // starting with buffer "The quick brown fox jumped over the lazy dog"
          let mut sequence1 = generate_delete_list(vec![
              // Delete "The  brown"
              (0, 10),
              // Delete "jumped  the  dog"
              (2, 16),
          ], 1, 0);
          // After these operations run, we will have " "
          let mut sequence2 = generate_delete_list(vec![
              // Delete "quick"
              (4, 5),
              // Delete "fox"
              (11, 3),
              // Delete "over"
              (19, 4),
              // Delete "lazy"
              (24, 4),
          ], 2, 2);
          // After these operations, we will have "The  brown  jumped  the  dog"
          Engine::split_by(&mut sequence1, &sequence2);
          Engine::swap(&mut sequence1, &mut sequence2);
          assert_eq!(to_delete_tuple_vec(&sequence1), vec![
              // Delete "The "
              (0, 4),
              // Delete " brown"
              (5, 6),
              // Delete "jumped "
              (10, 7),
              // Delete " the "
              (14, 5),
              // Delete " dog"
              (18, 4),
          ]);
          // After these, we will have "quick fox overlazy"
          assert_eq!(to_delete_tuple_vec(&sequence2), vec![
              // Delete "quick"
              (0, 5),
              // Delete "fox"
              (1, 3),
              // Delete "over"
              (2, 4),
              // Delete "lazy"
              (2, 4),
          ]);
      }

      #[test]
      fn test_integrate_sequences(){
          let mut engine = Engine::new(1);
          engine.inserts = generate_insert_list(vec![
              (0, "The quick brown fox"),
              // insert "very " after "the"
              (4, "very "),
              // insert "ly" after "quick"
              (14, "ly"),
              // insert "u" after the 'o' in "brown"
              (20, "u"),
          ], 1, 1);
          engine.inserts.front_mut().unwrap().set_timestamp(0);
          // After the inserts are applied, we would have "The very quickly brouwn fox"

          engine.deletes = generate_delete_list(vec![
              // delete the "e" from "the"
              (2, 1),
              // delete the "e" from "very"
              (4, 1),
              // delete the "ui" from "quickly"
              (8, 2),
              // delete the "ou" from "brouwn"
              (15, 2),
              // delete the "o" from "fox"
              (19, 1),
          ], 1, 1);
          let mut stamper = TimeStamper::new();
          stamper.stamp_local(1);
          stamper.stamp_local(1);
          stamper.stamp_remote(2, 0);
          // After the deletes are applied, we would have "Th vry qckly brwn fx"
          let mut lookup = BTreeMap::new();
          lookup.insert(0, (2, 0));
          let mut sequence = TransactionSequence::new(Some((1, 0)), generate_insert_list(vec![
              // Add an "ee" after "the"
              (3, "ee"),
              // Add another "k" on the end of "quick"
              (11, "k"),
              // Add "wnwnwn" to the end of "brown"
              (18, "wnwnwn"),
              // Add "xx!" to the end of "fox"
              (28, "xx!"),
          ], 2, 0), generate_delete_list(vec![  // After the inserts, we would have "Theee quickk brownwnwnwn foxxx!"
              // Delete the "he" from "theee"
              (1, 2),
              // Delete "bro" from "brownwnwnwn"
              (11, 3),
              // Delete "f" from "foxxx"
              (20, 1)
          ], 2, 0));
          // After the deletes, we would have "Tee quickk wnwnwnwn oxxx!"

          engine.integrate_remote(&mut sequence, &lookup, &mut stamper).unwrap();

          assert_eq!(to_insert_tuple_vec(&sequence.inserts), vec![
              // Add an "ee" after "th"
              (2, "ee"),
              // Add a "k" after "qckly"
              (14, "k"),
              // Add a "wnwnwn" after "brwn"
              (20, "wnwnwn"),
              // Add "xx!" after "fx"
              (29, "xx!")
          ]);
          // After these are applied, we would have "Thee vry qcklyk brwnwnwnwn fxxx!"
          assert_eq!(to_delete_tuple_vec(&sequence.deletes), vec![
              // Delete the "h" in "thee"
              (1, 1),
              // Delete "br"
              (15, 2),
              // Delete "f"
              (24, 1)
          ]);
          // After these are applied, we would have "Tee vry qcklyk wnwnwnwn xxx!"

          assert_eq!(to_insert_tuple_vec(&engine.inserts), vec![
              (0, "The quick brown fox"),
              // Add an "ee" after "the"
              (3, "ee"),
              // insert "very " after "theee "
              (6, "very "),
              // insert "ly" after "quick"
              (16, "ly"),
              // Add another "k" on the end of "quick"
              (18, "k"),
              // insert "u" after the 'o' in "brown"
              (23, "u"),
              // Add "wnwnwn" to the end of "brown"
              (26, "wnwnwn"),
              // Add "xx!" to the end of "fox"
              (36, "xx!"),
          ]);
          // After all the inserts are applied, we should have "Theee very quicklyk brouwnwnwnwn foxxx!"
          assert_eq!(to_delete_tuple_vec(&engine.deletes), vec![
              // Delete the "h" from "thee"
              (1, 1),
              // delete the first "e" from "teee"
              (1, 1),
              // delete the "e" from "very"
              (5, 1),
              // delete the "ui" from "quicklyk"
              (9, 2),
              // Delete "br" from "brouwnwnwnwn"
              (15, 2),
              // delete the "ou" from "brouwn"
              (15, 2),
              // Delete "f" from "foxxx!"
              (24, 1),
              // delete the "o" from "oxxx!"
              (24, 1),
          ]);
          // After all the deletes are applied, we should have "Tee vry qcklyk wnwnwnwn xxx!"

          let insert_timestamps:Vec<_> = engine.inserts.iter().map(InsertOperation::get_timestamp).collect();
          assert_eq!(insert_timestamps, vec![0, 2, 1, 1, 2, 1, 2, 2]);
      }
      #[test]
      fn test_process_transaction() {
        let mut engine = Engine::new(1);
        engine.inserts = generate_insert_list(vec![
            (0, "The quick brown fox"),
            // insert "very " after "the"
            (4, "very "),
            // insert "ly" after "quick"
            (14, "ly"),
            // insert "u" after the 'o' in "brown"
            (20, "u"),
        ], 1, 0);
        engine.inserts.front_mut().unwrap().set_timestamp(0);
        // After the inserts are applied, we would have "The very quickly brouwn fox"

        engine.deletes = generate_delete_list(vec![
            // delete the "e" from "the"
            (2, 1),
            // delete the "e" from "very"
            (4, 1),
            // delete the "ui" from "quickly"
            (8, 2),
            // delete the "ou" from "brouwn"
            (15, 2),
            // delete the "o" from "fox"
            (19, 1),
        ], 1, 4);

        // After the deletes are applied, we would have "Th vry qckly brwn fx"

        let mut sequence = TransactionSequence::new(Some((1, 0)), generate_insert_list(vec![
            // Add an "ee" after "th"
            (2, "ee"),
            // Add another "k" on the end of "quickly"
            (14, "k"),
            // Add "wnwnwn" to the end of "brown"
            (20, "wnwnwn"),
            // Add "xx!" to the end of "fox"
            (29, "xx!"),
            // After the inserts, we would have "Thee vry qcklyk brwnwnwnwn fxxx!"
        ], 2, 0), generate_delete_list(vec![
            // Delete the "h" from "thee"
            (1, 1),
            // Delete "br" from "brwnwnwnwn"
            (15, 2),
            // Delete "f" from "foxxx!"
            (24, 1)
        ], 2, 4));
        // After the deletes, we would have "Tee vry qcklyk wnwnwnwn oxxx!"

        engine.process_transaction(&mut sequence);

        assert_eq!(to_insert_tuple_vec(&sequence.inserts), vec![
            // Add an "ee" after "th"
            (3, "ee"),
            // Add a "k" after "qckly"
            (18, "k"),
            // Add a "wnwnwn" after "brwn"
            (26, "wnwnwn"),
            // Add "xx!" after "fx"
            (36, "xx!")
        ]);
        // After the inserts are applied, we would have "Theee very quicklyk brouwnwnwnwn foxxx!"
        assert_eq!(to_delete_tuple_vec(&sequence.deletes), vec![
            // Delete the "h" in "theee"
            (1, 1),
            // Delete "br"
            (19, 2),
            // Delete "f"
            (30, 1)
        ]);
        // After these are applied, we would have "Teee very quicklyk ouwnwnwnwn oxxx!"

        assert_eq!(to_insert_tuple_vec(&engine.inserts), vec![
            (0, "The quick brown fox"),
            // Add an "ee" after "the"
            (3, "ee"),
            // insert "very " after "theee "
            (6, "very "),
            // insert "ly" after "quick"
            (16, "ly"),
            // Add another "k" on the end of "quick"
            (18, "k"),
            // insert "u" after the 'o' in "brown"
            (23, "u"),
            // Add "wnwnwn" to the end of "brown"
            (26, "wnwnwn"),
            // Add "xx!" to the end of "fox"
            (36, "xx!"),

        ]);
        // After all the inserts are applied, we should have "Theee very quicklyk brouwnwnwnwn foxxx!"
        assert_eq!(to_delete_tuple_vec(&engine.deletes), vec![
            // Delete the "h" from "thee"
            (1, 1),
            // delete the first "e" from "teee"
            (1, 1),
            // delete the "e" from "very"
            (5, 1),
            // delete the "ui" from "quicklyk"
            (9, 2),
            // Delete "br" from "brouwnwnwnwn"
            (15, 2),
            // delete the "ou" from "brouwn"
            (15, 2),
            // Delete "f" from "foxxx!"
            (24, 1),
            // delete the "o" from "oxxx!"
            (24, 1),
        ]);
        // After all the deletes are applied, we should have "Tee vry qcklyk wnwnwnwn xxx!"
    }

    #[test]
    fn full_process() {
        let _ = env_logger::init().unwrap();
        let mut engine = Engine::new(1);
        engine.inserts = generate_insert_list(vec![
            (0, "Some words"),
            (8, "ds and these words!"),
            (8, "ds and something in the middle and t")
        ], 1, 0);
        engine.deletes = generate_delete_list(vec![
            (44, 8),
            (55, 2)
        ], 1, 0);
        let mut stamper = TimeStamper::new();
        stamper.stamp_local(1);
        let mut engine2 = engine.clone();
        engine2.site_id = 2;

        let mut lookup = BTreeMap::new();
        lookup.insert(0, (1, 0));
        let mut transaction = TransactionSequence::new(Some((1, 0)), LinkedList::new(), generate_delete_list(vec![
            (0, 55)
        ], 1, 0));

        engine.process_transaction(&mut transaction);

        assert_eq!(to_delete_tuple_vec(&transaction.deletes), vec![
            (0, 44),
            (8, 11)
        ]);

        assert_eq!(to_delete_tuple_vec(&engine.deletes), vec![
            (0, 44),
            (0, 8),
            (0, 11),
            (0, 2),
        ]);

        engine2.integrate_remote(&mut transaction, &lookup, &mut stamper).unwrap();

        assert_eq!(to_delete_tuple_vec(&transaction.deletes), vec![
            (0, 44),
            (0, 11)
        ]);

        assert_eq!(to_delete_tuple_vec(&engine2.deletes), vec![
            (0, 44),
            (0, 8),
            (0, 11),
            (0, 2),
        ]);

    }

}