#include <limits>
#include <map>
#include "luastack.hpp"
#include "animqueue.hpp"
#include "streambuffer.hpp"
#include <ostream>
#include <sstream>

AnimStep::AnimStep() {
    clear();
}

AnimStep::~AnimStep() {}


void AnimStep::clear() {
    id_ = 0;
    bits_ = 0;
    action_ = "";
    facing_ = 0;
    xyz_ = util::XYZ(0,0,0);
    graphic_ = "";
    plane_ = "";
}

void AnimStep::set_action(const std::string &act) {
    action_ = act;
}

void AnimStep::set_facing(float f) {
    bits_ |= HAS_FACING;
    facing_ = f;
}

void AnimStep::set_x(float f) {
    bits_ |= HAS_X;
    xyz_.x = f;
}

void AnimStep::set_y(float f) {
    bits_ |= HAS_Y;
    xyz_.y = f;
}

void AnimStep::set_z(float f) {
    bits_ |= HAS_Z;
    xyz_.z = f;
}

void AnimStep::set_xyz(const util::XYZ &xyz) {
    bits_ |= (HAS_X | HAS_Y | HAS_Z);
    xyz_ = xyz;
}

void AnimStep::set_graphic(const std::string &g) {
    bits_ |= HAS_GRAPHIC;
    graphic_ = g;
}

void AnimStep::set_plane(const std::string &p) {
    bits_ |= HAS_PLANE;
    plane_ = p;
}


bool AnimStep::exactly_equal(const AnimStep &other) const {
    if (id_ != other.id_) return false;
    if (bits_ != other.bits_) return false;
    if (action_ != other.action_) return false;
    if (facing_ != other.facing_) return false;
    if (xyz_ != other.xyz_) return false;
    if (graphic_ != other.graphic_) return false;
    if (plane_ != other.plane_) return false;
    return true;
}

bool AnimStep::logically_equal(const AnimStep &other) const {
    if (id_ != other.id_) return false;
    if (bits_ != other.bits_) return false;
    if (action_ != other.action_) return false;
    if (has_facing() && (facing_ != other.facing_)) return false;
    if (has_x() && (xyz_.x != other.xyz_.x)) return false;
    if (has_y() && (xyz_.y != other.xyz_.y)) return false;
    if (has_z() && (xyz_.z != other.xyz_.z)) return false;
    if (has_graphic() && (graphic_ != other.graphic_)) return false;
    if (has_plane() && (plane_ != other.plane_)) return false;
    return true;
}

bool AnimStep::state_equal(const AnimStep &other) const {
    if (facing_ != other.facing_) return false;
    if (xyz_ != other.xyz_) return false;
    if (graphic_ != other.graphic_) return false;
    if (plane_ != other.plane_) return false;
    return true;
}

void AnimStep::write_into(StreamBuffer *sb) const {
    sb->write_int64(id_);
    sb->write_int16(bits_);
    sb->write_string(action_);
    if (has_facing()) {
        sb->write_float(facing_);
    }
    if (has_x()) {
        sb->write_float(xyz_.x);
    }
    if (has_y()) {
        sb->write_float(xyz_.y);
    }
    if (has_z()) {
        sb->write_float(xyz_.z);
    }
    if (has_graphic()) {
        sb->write_string(graphic_);
    }
    if (has_plane()) {
        sb->write_string(plane_);
    }
}

void AnimStep::read_from(StreamBuffer *sb) {
    id_ = sb->read_int64();
    bits_ = sb->read_int16();
    action_ = sb->read_string();
    if (has_facing()) {
        facing_ = sb->read_float();
    }
    if (has_x()) {
        xyz_.x = sb->read_float();
    }
    if (has_y()) {
        xyz_.y = sb->read_float();
    }
    if (has_z()) {
        xyz_.z = sb->read_float();
    }
    if (has_graphic()) {
        graphic_ = sb->read_string();
    }
    if (has_plane()) {
        plane_ = sb->read_string();
    }
}


void AnimStep::from_lua_store_string(lua_State *L, int idx, std::string *target, int16_t bits, const char *name) {
    if ((bits_ & bits)||(*target != "")) {
        luaL_error(L, "specified %s twice", name);
    }
    if (lua_type(L, idx) != LUA_TSTRING) {
        luaL_error(L, "Expected %s to be a string", name);
    }
    *target = lua_tostring(L, idx);
    bits_ |= bits;
}

void AnimStep::from_lua_store_number(lua_State *L, int idx, float *target, float offset, int16_t bits, const char *name) {
    if (bits_ & bits) {
        luaL_error(L, "specified %s twice", name);
    }
    if (lua_type(L, idx) != LUA_TNUMBER) {
        luaL_error(L, "Expected %s to be a number", name);
    }
    *target = lua_tonumber(L, idx) + offset;
    bits_ |= bits;
}

void AnimStep::from_lua(lua_State *L, int idx, const AnimStep &qback) {
    LuaSpecial tab(idx);
    LuaVar key, value;
    LuaStack LS(L, key, value);
    if (!LS.istable(tab)) {
        luaL_error(L, "animation spec must be a table");
    }
    LS.set(key, LuaNil);
    while (LS.next(tab, key, value)) {
        if (!LS.isstring(key)) {
            luaL_error(L, "animation specs must be key/value where key is a string");
        }
        std::string skey = LS.ckstring(key);
        if (skey == "action") {
            from_lua_store_string(L, value.index(), &action_, 0, "action");
        } else if (skey == "graphic") {
            from_lua_store_string(L, value.index(), &graphic_, HAS_GRAPHIC, "graphic");
        } else if (skey == "plane") {
            from_lua_store_string(L, value.index(), &plane_, HAS_PLANE, "plane");
        } else if (skey == "x") {
            from_lua_store_number(L, value.index(), &xyz_.x, 0.0, HAS_X, "X coordinate");
        } else if (skey == "y") {
            from_lua_store_number(L, value.index(), &xyz_.y, 0.0, HAS_Y, "Z coordinate");
        } else if (skey == "z") {
            from_lua_store_number(L, value.index(), &xyz_.z, 0.0, HAS_Z, "Z coordinate");
        } else if (skey == "dx") {
            from_lua_store_number(L, value.index(), &xyz_.x, qback.xyz().x, HAS_X, "X coordinate");
        } else if (skey == "dy") {
            from_lua_store_number(L, value.index(), &xyz_.y, qback.xyz().y, HAS_Y, "Y coordinate");
        } else if (skey == "dz") {
            from_lua_store_number(L, value.index(), &xyz_.z, qback.xyz().z, HAS_Z, "Z coordinate");
        } else if (skey == "facing") {
            from_lua_store_number(L, value.index(), &facing_, 0.0, HAS_FACING, "facing");
        } else {
            luaL_error(L, "Unrecognized animation spec: %s", skey.c_str());
        }
    }
}

void AnimStep::keep_state_only() {
    bits_ = HAS_EVERYTHING;
    id_ = 0;
    action_ = "";
}

void AnimStep::echo(const AnimStep &prev) {
    if (!has_facing()) {
        facing_ = prev.facing_;
    }
    if (!has_x()) {
        xyz_.x = prev.xyz_.x;
    }
    if (!has_y()) {
        xyz_.y = prev.xyz_.y;
    }
    if (!has_z()) {
        xyz_.z = prev.xyz_.z;
    }
    if (!has_graphic()) {
        graphic_ = prev.graphic_;
    }
    if (!has_plane()) {
        plane_ = prev.plane_;
    }
}

bool AnimStep::echoes(const AnimStep &prev) const {
    if (!has_facing() && (facing_ != prev.facing_)) {
        return false;
    }
    if (!has_x() && (xyz_.x != prev.xyz_.x)) {
        return false;
    }
    if (!has_y() && (xyz_.y != prev.xyz_.y)) {
        return false;
    }
    if (!has_z() && (xyz_.z != prev.xyz_.z)) {
        return false;
    }
    if (!has_graphic() && (graphic_ != prev.graphic_)) {
        return false;
    }
    if (!has_plane() && (plane_ != prev.plane_)) {
        return false;
    }
    return true;
}

std::string AnimStep::debug_string() const {
    std::ostringstream oss;
    oss << "id=" << id();
    oss << " action=" << action();
    if (has_plane()) {
        oss << " plane=" << plane();
    }
    if (has_x()) {
        oss << " x=" << xyz().x;
    }
    if (has_y()) {
        oss << " y=" << xyz().y;
    }
    if (has_z()) {
        oss << " z=" << xyz().z;
    }
    if (has_facing()) {
        oss << " facing=" << facing();
    }
    if (has_graphic()) {
        oss << " graphic=" << graphic();
    }
    return oss.str();
}


bool AnimStep::from_string(const std::string &config) {
    clear();
    util::StringVec parts = util::split(config, ' ');
    for (int i = 0; i < int(parts.size()); i++) {
        const std::string &part = parts[i];
        if (part == "") continue;
        util::StringVec lr = util::split(part, '=');
        if (lr.size() != 2) return false;
        const std::string &key = lr[0];
        const std::string &val = lr[1];
        if (key == "action") {
            action_ = val;
        } else if (key == "id") {
            int64_t id = util::strtoint(val, -1);
            if (id < 0) return false;
            id_ = id;
        } else if (key == "plane") {
            set_plane(val);
        } else if (key == "x") {
            double v = util::strtodouble(val);
            if (std::isnan(v)) return false;
            set_x(v);
        } else if (key == "y") {
            double v = util::strtodouble(val);
            if (std::isnan(v)) return false;
            set_y(v);
        } else if (key == "z") {
            double v = util::strtodouble(val);
            if (std::isnan(v)) return false;
            set_z(v);
        } else if (key == "facing") {
            double v = util::strtodouble(val);
            if (std::isnan(v)) return false;
            set_facing(v);
        } else if (key == "graphic") {
            set_graphic(val);
        } else {
            return false;
        }
    }
    return true;
}

AnimQueue::AnimQueue(util::WorldType wt) {
    version_autoinc_ = (wt == util::WORLD_TYPE_MASTER);
    size_limit_ = 10; // Default size limit.
    steps_.emplace_back();
    steps_.front().keep_state_only();
    version_number_ = version_autoinc_ ? 1 : 0;
}

void AnimQueue::mutated() {
    if (version_autoinc_) {
        version_number_ += 1;
    } else {
        version_number_ = 0;
    }
}

bool AnimQueue::size_and_steps_equal(const AnimQueue &other) const {
    if (size_limit_ != other.size_limit_) {
        return false;
    }
    if (steps_.size() != other.steps_.size()) {
        return false;
    }
    for (int i = 0; i < int(steps_.size()); i++) {
        if (!steps_[i].exactly_equal(other.steps_[i])) {
            return false;
        }
    }
    return true;
}

void AnimQueue::full_clear_and_set_limit(int n) {
    assert(n >= 1);
    steps_.clear();
    steps_.emplace_back();
    steps_.front().keep_state_only();
    size_limit_ = n;
    version_number_ = version_autoinc_ ? 1 : 0;
}

void AnimQueue::clear(const std::string &plane) {
    steps_.clear();
    steps_.emplace_back();
    steps_.front().set_plane(plane);
    steps_.front().keep_state_only();
    mutated();
}

void AnimQueue::set_limit(int n) {
    assert(n >= 1);
    size_limit_ = n;
    if (int(steps_.size()) > n) {
        while (int(steps_.size()) > n) {
            steps_.pop_front();
        }
        steps_.front().keep_state_only();
    }
    mutated();
}

void AnimQueue::add(int64_t id, const AnimStep &step) {
    AnimStep copy = step;
    copy.echo(steps_.back());
    copy.id_ = id;
    steps_.push_back(copy);
    while (int(steps_.size()) > size_limit_) {
        steps_.pop_front();
    }
    steps_.front().keep_state_only();
    mutated();
}

bool AnimQueue::valid() const {
    // Size limit must be between 2 and 250
    if ((size_limit_ < 1) || (size_limit_ > 250)) {
        return false;
    }
    // Animqueue must have at least one step, and no more than 250.
    if (steps_.empty()) {
        return false;
    }
    if (steps_.size() > 250) {
        return false;
    }
    // First action should be blank.
    if (steps_[0].action_ != "") {
        return false;
    }
    // First step should have all bits.
    if (steps_[0].bits_ != AnimStep::HAS_EVERYTHING) {
        return false;
    }
    // Any unset bit should correspond to a value copied from the previous step.
    for (size_t i = 1; i < steps_.size(); i++) {
        const AnimStep &prev = steps_[i - 1];
        const AnimStep &curr = steps_[i];
        if (!curr.echoes(prev)) return false;
    }
    return true;
}

std::string AnimQueue::steps_debug_string() const {
    std::ostringstream oss;
    for (int i = 0; i < int(size()); i++) {
        oss << nth(i).debug_string() << "; ";
    }
    return oss.str();
}

std::string AnimQueue::full_debug_string() const {
    std::ostringstream oss;
    for (int i = 0; i < int(size()); i++) {
        oss << nth(i).debug_string() << "; ";
    }
    oss << "version=" << version_number();
    oss << "; limit=" << size_limit();
    return oss.str();
}

void AnimQueue::serialize(StreamBuffer *sb) const {
    assert(valid()); // can't serialize an invalid animqueue.
    sb->write_uint8(size_limit_);
    sb->write_uint8(steps_.size());
    for (const AnimStep &step : steps_) {
        step.write_into(sb);
    }
}

void AnimQueue::deserialize(StreamBuffer *sb) {
    size_limit_ = sb->read_uint8();
    size_t nsteps = sb->read_uint8();
    steps_.resize(nsteps);
    for (size_t i = 0; i < nsteps; i++) {
        AnimStep &step = steps_[i];
        step.read_from(sb);
        if (i > 0) step.echo(steps_[i - 1]);
    }
    version_number_ = 0;
}

bool AnimQueue::version_identical(const AnimQueue &auth) const {
    return version_number_ == auth.version_number_;
}

bool AnimQueue::diff(const AnimQueue &auth, StreamBuffer *sb) const {
    assert(valid());
    assert(auth.valid());

    // Fast path to equivalence detection
    if (version_identical(auth)) {
        assert(size_and_steps_equal(auth));
        sb->write_uint8(255);
        return false;
    }

    // Another path to equivalence detection
    if (size_and_steps_equal(auth)) {
        sb->write_uint8(255);
        return false;
    }

    // Write the first element.
    assert(auth.steps_.size() < 255);
    sb->write_uint8(auth.steps_.size());
    sb->write_uint8(auth.size_limit_);
    const AnimStep &first = auth.steps_[0];
    int match = 0;
    while ((match < int(steps_.size())) && (!steps_[match].state_equal(first))) {
        match++;
    }
    if (match == int(steps_.size())) {
        sb->write_uint8(255);
        first.write_into(sb);
    } else {
        sb->write_uint8(match);
    }

    // Index the remaining elements by id.
    std::map<uint64_t, int> index;
    for (int i = 1; i < int(steps_.size()); i++) {
        index[steps_[i].id_] = i;
    }

    // Write the remaining elements.
    for (int i = 1; i < int(auth.steps_.size()); i++) {
        const AnimStep &step = auth.steps_[i];
        auto iter = index.find(step.id());
        if (iter == index.end()) {
            sb->write_uint8(255);
            step.write_into(sb);
        } else {
            const AnimStep &local = steps_[iter->second];
            if (local.exactly_equal(step)) {
                sb->write_uint8(iter->second);
            } else {
                sb->write_uint8(255);
                step.write_into(sb);
            }
        }
    }
    return true;
}

void AnimQueue::patch(StreamBuffer *sb, DebugCollector *dbc) {
    int len = sb->read_uint8();
    if (len == 255) {
        return;
    }
    DebugLine(dbc) << "AnimQueue modified";

    size_limit_ = sb->read_uint8();
    // Decode the diff, stop at eof.
    std::deque<AnimStep> old = std::move(steps_);
    steps_.clear();
    for (int i = 0; i < len; i++) {
        uint8_t index = sb->read_uint8();
        if (index < 255) {
            assert(index < old.size());
            steps_.push_back(old[index]);
        } else {
            AnimStep step;
            step.read_from(sb);
            steps_.push_back(step);
        }
        int size = steps_.size();
        if (size > 1) {
            steps_[size-1].echo(steps_[size-2]);
        } else {
            steps_[0].keep_state_only();
        }
    }
    mutated();
}

void AnimQueue::update_version(const AnimQueue &auth) {
    assert(size_and_steps_equal(auth));
    version_number_ = auth.version_number_;
}

const AnimStep &AnimQueue::back() const {
    return steps_.back();
}

static bool diff_works(const AnimQueue &master, AnimQueue &sync) {
    StreamBuffer sb;
    sync.diff(master, &sb);
    sync.patch(&sb, nullptr);
    return sync.size_and_steps_equal(master);
}

LuaDefine(unittests_animqueue, "c") {
    // Useful objects.
    AnimStep stp;
    AnimQueue aq(util::WORLD_TYPE_MASTER);
    AnimQueue aqds(util::WORLD_TYPE_S_SYNC);
    StreamBuffer sb;
    
    // Debug string of a newly initialized queue
    LuaAssert(L, aq.valid());
    LuaAssertStrEq(L, aq.full_debug_string(), "id=0 action= plane= x=0 y=0 z=0 facing=0 graphic=; version=1; limit=10");

    // Test the step setters.
    stp.clear();
    LuaAssertStrEq(L, stp.debug_string(), "id=0 action=");
    stp.set_facing(180);
    LuaAssertStrEq(L, stp.debug_string(), "id=0 action= facing=180");
    stp.set_x(3);
    LuaAssertStrEq(L, stp.debug_string(), "id=0 action= x=3 facing=180");
    stp.set_y(4);
    LuaAssertStrEq(L, stp.debug_string(), "id=0 action= x=3 y=4 facing=180");
    stp.set_z(5);
    LuaAssertStrEq(L, stp.debug_string(), "id=0 action= x=3 y=4 z=5 facing=180");
    stp.set_plane("somewhere");
    LuaAssertStrEq(L, stp.debug_string(), "id=0 action= plane=somewhere x=3 y=4 z=5 facing=180");
    stp.set_graphic("something");
    LuaAssertStrEq(L, stp.debug_string(), "id=0 action= plane=somewhere x=3 y=4 z=5 facing=180 graphic=something");

    // Test the step debug string parser.
    LuaAssert(L, stp.from_string("id=123 action=walk x=1 y=2 z=3 facing=4 plane=p graphic=g"));
    LuaAssertStrEq(L, stp.debug_string(), "id=123 action=walk plane=p x=1 y=2 z=3 facing=4 graphic=g");

    // Test that we can clear a queue.
    aq.full_clear_and_set_limit(3);
    LuaAssert(L, aq.valid());
    LuaAssertStrEq(L, aq.full_debug_string(), "id=0 action= plane= x=0 y=0 z=0 facing=0 graphic=; version=1; limit=3");
    
    // Add a step to a queue.
    aq.full_clear_and_set_limit(3);
    LuaAssert(L, stp.from_string("action=walk"));
    aq.add(12345, stp);
    LuaAssertStrEq(L, aq.full_debug_string(),
        "id=0 action= plane= x=0 y=0 z=0 facing=0 graphic=; "
        "id=12345 action=walk; "
        "version=2; limit=3");

    // Exceed the length limit, dropping first element.
    aq.full_clear_and_set_limit(3);
    LuaAssert(L, stp.from_string("action=walk plane=foo"));
    aq.add(12345, stp);
    aq.add(12346, stp);
    aq.add(12347, stp);
    LuaAssertStrEq(L, aq.full_debug_string(),
        "id=0 action= plane=foo x=0 y=0 z=0 facing=0 graphic=; "
        "id=12346 action=walk plane=foo; "
        "id=12347 action=walk plane=foo; "
        "version=4; limit=3"
    );

    // Test serialization and deserialization.
    aq.full_clear_and_set_limit(5);
    LuaAssert(L, stp.from_string("action=walk x=3 y=4 z=5"));
    aq.add(12345, stp);
    LuaAssert(L, stp.from_string("action=setgraphic graphic=banana"));
    aq.add(12346, stp);
    LuaAssert(L, stp.from_string("action=setfacing facing=301"));
    aq.add(12347, stp);

    aq.serialize(&sb);
    aqds.deserialize(&sb);

    LuaAssertStrEq(L, aqds.full_debug_string(), 
        "id=0 action= plane= x=0 y=0 z=0 facing=0 graphic=; "
        "id=12345 action=walk x=3 y=4 z=5; "
        "id=12346 action=setgraphic graphic=banana; "
        "id=12347 action=setfacing facing=301; "
        "version=0; limit=5"
    );
    
    // Test difference transmission
    aq.full_clear_and_set_limit(10);
    aqds.full_clear_and_set_limit(10);
    
    // Add a single action to the queue and DT
    LuaAssert(L, stp.from_string("action=walk x=3 y=4 z=5"));
    aq.add(12345, stp);
    LuaAssert(L, diff_works(aq, aqds));

    // Add another action and DT
    LuaAssert(L, stp.from_string("action=fnord plane=where facing=123"));
    aq.add(232, stp);
    LuaAssert(L, diff_works(aq, aqds));

    // Change the queue size limit.
    aq.set_limit(13);
    LuaAssert(L, diff_works(aq, aqds));

    // compare again, should be no differences.
    LuaAssert(L, aqds.version_identical(aq));
    LuaAssert(L, aqds.size_and_steps_equal(aq));
    LuaAssert(L, diff_works(aq, aqds));

    // Discard all but the last action.
    aq.set_limit(1);
    LuaAssert(L, diff_works(aq, aqds));

    return 0;
}