#include "world.hpp"
#include "idalloc.hpp"
#include "animqueue.hpp"
#include "gui.hpp"
#include "traceback.hpp"
#include <iostream>

void World::store_global_pointer(lua_State *L, World *v) {
    lua_pushstring(L, "world");
    lua_pushlightuserdata(L, v);
    lua_rawset(L, LUA_REGISTRYINDEX);
}

World *World::fetch_global_pointer(lua_State *L) {
    lua_pushstring(L, "world");
    lua_rawget(L, LUA_REGISTRYINDEX);
    World *result = (World *)lua_touserdata(L, -1);
    if (result == nullptr) {
        luaL_error(L, "No world pointer stored.");
    }
    lua_pop(L, 1);
    return result;
}

World::~World() {
}

World::World() {    
    // Initialize the ID allocator in master mode.
    id_global_pool_.init_master(10);

    // Prepare to manipulate the lua state.
    LuaVar world;
    LuaStack LS(state(), world);

    // Put the world pointer into the lua registry.
    World::store_global_pointer(state(), this);

    // Clear the global GUI pointer.
    Gui::store_global_pointer(state(), nullptr);

    // Create the tangibles table in the registry.
    LS.rawset(LuaRegistry, "tangibles", LuaNewTable);

    // Initialize the SourceDB
    source_db_.init(state());
    source_db_.rebuild();

    LS.result();
    assert (lua_gettop(state()) == 0);
}

Tangible::Tangible(World *w, int64_t id) : world_(w), id_player_pool_(&w->id_global_pool_) {
    plane_item_.set_id(id);
    plane_item_.track(&w->plane_map_);
}

void Tangible::update_plane_item() {
    const AnimStep &aqback = anim_queue_.back();
    plane_item_.set_pos(aqback.plane(), aqback.xyz().x, aqback.xyz().y, aqback.xyz().z);
}

void Tangible::serialize(StreamBuffer *sb) {
    anim_queue_.serialize(sb);
    id_player_pool_.serialize(sb);
}

void Tangible::deserialize(StreamBuffer *sb) {
    anim_queue_.deserialize(sb);
    id_player_pool_.deserialize(sb);
    update_plane_item();
}

void World::init_standalone() {
    assert(stack_is_clear());

    // Load the lua source from disk then rebuild the environment.
    source_db_.update();
    source_db_.rebuild();

    // Run unit tests.
    source_db_.run_unittests();

    assert(stack_is_clear());
}

Tangible *World::tangible_get(int64_t id) {
    auto iter = tangibles_.find(id);
    if (iter == tangibles_.end()) {
        return nullptr;
    } else {
        return iter->second.get();
    }
}

Tangible *World::tangible_get(lua_State *L, int idx) {
    Tangible *result = nullptr;
    int top = lua_gettop(L);
    if (lua_istable(L, idx)) {
        lua_getmetatable(L, idx);
        if (lua_istable(L, -1)) {
            lua_pushstring(L, "id");
            lua_rawget(L, -2);
            lua_Number id = lua_tonumber(L, -1);
            result = tangible_get(int64_t(id));
        }
    }
    lua_settop(L, top);
    if (result == nullptr) {
        luaL_error(L, "parameter is not a tangible");
    }
    return result;
}

void World::tangible_delete(lua_State *L, int64_t id) {
    LuaVar tangibles, database;
    LuaStack LS(L, tangibles, database);

    // Fetch the C++ side of the tangible.
    auto iter = tangibles_.find(id);
    if (iter == tangibles_.end()) {
        luaL_error(L, "Not a tangible: %lld", id);
    }

    // Fetch the lua side of the tangible.
    LS.rawget(tangibles, LuaRegistry, "tangibles");
    LS.rawget(database, tangibles, id);
    assert(LS.istable(database));
    
    // Clear out the database.
    LS.clearmetatable(database);
    LS.cleartable(database);

    // Remove the lua portion from the table.
    LS.rawset(tangibles, id, LuaNil);

    // Remove the C++ portion from the table.
    tangibles_.erase(iter);
    LS.result();
}

std::vector<int64_t> World::get_near(int64_t player_id, float radius, bool exclude_nowhere) {
    Tangible *player = tangible_get(player_id);

    // Find out where's the center of the world.
    const AnimStep &aqback = player->anim_queue_.back();
    if (exclude_nowhere && (aqback.plane() == "nowhere")) {
        return std::vector<int64_t>();
    }
    
    return plane_map_.scan_radius(aqback.plane(), aqback.xyz().x, aqback.xyz().y, radius, player_id);
}

Tangible *World::tangible_make(lua_State *L, int64_t id, bool pushdb) {
    LuaVar tangibles, metatab;
    LuaRet database;
    LuaStack LS(L, tangibles, database, metatab);

    // Allocate an ID if we don't already have one.
    if (id == 0) id = id_global_pool_.alloc_id_for_thread(L);

    // Create the C++ part of the structure.
    std::unique_ptr<Tangible> &t = tangibles_[id];
    assert (t == nullptr);
    t.reset(new Tangible(this, id));
    
    // Create the tangible's database and metatable.
    LS.set(database, LuaNewTable);
    LS.set(metatab, LuaNewTable);
    LS.setmetatable(database, metatab);

    // Store the database into the tangibles table.
    LS.rawget(tangibles, LuaRegistry, "tangibles");
    LS.rawset(tangibles, id, database);

    // Populate the database and metatable with initial stuff.
    LS.rawset(database, "inventory", LuaNewTable);
    LS.rawset(metatab, "id", id);
    LS.rawset(metatab, "threads", LuaNewTable);
    // LS.rawset(metatab, "__metatable", LuaNil);

    LS.result();
    if (!pushdb) lua_pop(L, 1);
    return t.get();
}

World::Redirects World::fetch_redirects() {
    World::Redirects result = std::move(redirects_);
    redirects_.clear();
    return std::move(result);
}

// void Tangible::be_a_player() {
//     if (!id_player_pool_.fifo_enabled()) {
//         id_player_pool_.enable_fifo();

//         AnimStep asinit;
//         asinit.set_graphic("player");
//         anim_queue_.add(world_->id_global_pool_.get_one(), asinit);
//         anim_queue_.keep_only(1);
//         update_plane_item();

//         LuaVar classtab, mt, place, tangibles;
//         LuaStack LS(world_->state(), classtab, mt, place, tangibles);

//         LS.makeclass(classtab, "player");
//         LS.rawget(tangibles, LuaRegistry, "tangibles");
//         LS.rawget(place, tangibles, id());
//         LS.getmetatable(mt, place);
//         LS.rawset(mt, "__index", classtab);
//         LS.result();
//     }
// }

int64_t World::create_login_actor() {
    Tangible *tan = tangible_make(state(), 0, true);
    LuaArg database;
    LuaVar classtab, mt;
    LuaStack LS(state(), database, classtab, mt);
    LS.makeclass(classtab, "login");
    LS.getmetatable(mt, database);
    LS.rawset(mt, "__index", classtab);
    LS.result();
    tan->id_player_pool_.enable_fifo();
    assert(stack_is_clear());
    return tan->id();
}

void World::update_gui(int64_t actor_id, int64_t place_id, Gui *gui) {
    assert(stack_is_clear());
    gui->clear();
    lua_State *L = state();

    LuaVar actor, place, ugui, func, tangibles, mt, index;
    LuaStack LS(L, actor, place, ugui, func, tangibles, mt, index);

    // Get the actor and place.
    LS.rawget(tangibles, LuaRegistry, "tangibles");
    LS.rawget(actor, tangibles, actor_id);
    LS.rawget(place, tangibles, place_id);
    if (!LS.istable(actor) || !LS.istable(place)) {
        LS.result();
        return;
    }

    // Get the interface closure.
    LS.getmetatable(mt, place);
    if (!LS.istable(mt)) {
        LS.result();
        return;
    }
    LS.rawget(index, mt, "__index");
    if (!LS.istable(index)) {
        LS.result();
        return;
    }
    LS.rawget(func, index, "interface");
    if (!LS.isfunction(func)) {
        LS.result();
        return;
    }

    // Call the interface function.
    lua_pushvalue(L, func.index());
    lua_pushvalue(L, actor.index());
    lua_pushvalue(L, place.index());
    Gui::store_global_pointer(L, gui);
    int status = traceback_pcall(L, 2, 0);
    Gui::store_global_pointer(L, nullptr);
    if (status != 0) {
        gui->clear();
        std::cerr << lua_tostring(L, -1);
        LS.result();
        return;
    }

    // And we're done.
    LS.result();
    assert(stack_is_clear());
}

void World::invoke_plan(int64_t actor_id, int64_t place_id, const std::string &action, const GuiResult &gres) {
    assert(stack_is_clear());

    // Validate that the action is legal.
    Gui validation_gui;
    update_gui(actor_id, place_id, &validation_gui);
    if (!validation_gui.has_action(action)) {
        return;
    }

    // Get an ID batch for the thread, and take one for the thread itself.
    Tangible *tactor = tangible_get(actor_id);
    int64_t id_batch = tactor->id_player_pool_.get_batch();
    int64_t tid = id_batch++;

    // Set up for Lua manipulation.
    lua_State *L = state();
    LuaVar actor, place, func, tangibles, mt, index, actions, thread, threads, message, guires;
    LuaStack LS(L, actor, place, func, tangibles, mt, index, actions, thread, threads, message, guires);

    // Get the actor and place.
    LS.rawget(tangibles, LuaRegistry, "tangibles");
    LS.rawget(actor, tangibles, actor_id);
    LS.rawget(place, tangibles, place_id);
    if (!LS.istable(actor) || !LS.istable(place)) {
        LS.result();
        return;
    }

    // Get the action closure.
    LS.getmetatable(mt, place);
    if (!LS.istable(mt)) {
        LS.result();
        return;
    }
    LS.rawget(index, mt, "__index");
    if (!LS.istable(index)) {
        LS.result();
        return;
    }
    LS.rawget(actions, index, "action");
    if (!LS.istable(actions)) {
        LS.result();
        return;
    }
    LS.rawget(func, actions, action);
    if (!LS.isfunction(func)) {
        LS.result();
        return;
    }

    // Convert the GuiResult into a lua table.
    LS.newtable(guires);
    for (const auto &p : gres) {
        LS.rawset(guires, p.first, p.second);
    }

    // Create a new thread, set up function and parameters.
    lua_State *CO = LS.newthread(thread);
    lua_pushvalue(L, func.index());
    lua_pushvalue(L, actor.index());
    lua_pushvalue(L, place.index());
    lua_pushvalue(L, guires.index());
    lua_xmove(L, CO, 4);

    // Store the thread into place's thread table.
    LS.rawget(threads, mt, "threads");
    if (!LS.istable(threads)) {
        LS.result();
        return;
    }
    LS.rawset(threads, tid, thread);
    LS.result();
    
    // Push the thread's ID into the runnable thread queue,
    // then run the thread queue.
    thread_sched_.add(0, tid, place_id);
    run_scheduled_threads(0);
    assert(stack_is_clear());
}

void World::run_scheduled_threads(int64_t clk) {
    assert(stack_is_clear());
    lua_State *L = state();
    LuaVar tangibles, place, mt, threads, thread;
    LuaStack LS(L, tangibles, place, mt, threads, thread);
    LS.rawget(tangibles, LuaRegistry, "tangibles");

    while (thread_sched_.ready(clk)) {
        SchedEntry sched = thread_sched_.pop();
        LS.rawget(place, tangibles, sched.place_id());
        if (!LS.istable(place)) {
            continue;
        }
        LS.getmetatable(mt, place);
        if (!LS.istable(mt)) {
            continue;
        }
        LS.rawget(threads, mt, "threads");
        if (!LS.istable(threads)) {
            continue;
        }
        LS.rawget(thread, threads, sched.thread_id());
        if (!LS.isthread(thread)) {
            continue;
        }

        // Resume the coroutine.
        lua_State *CO = LS.ckthread(thread);
        int top = lua_gettop(CO);
        int status = lua_resume(CO, nullptr, (top > 0) ? (top - 1) : 0);

        // Three possible outcomes: finished, yielded, or errored.
        if (status == LUA_YIELD) {
            // When the wait statement yields, it yields the desired timestamp.
            if ((lua_gettop(CO) != 1) || (!lua_isnumber(CO, 1))) {
                std::cerr << "Thread yielded incorrectly.  Killing it." << std::endl;
                LS.rawset(threads, sched.thread_id(), LuaNil);
            } else {
                lua_Number delay = lua_tonumber(CO, 1);
                lua_settop(CO, 0);
                std::cerr << "Thread wait = " << delay << std::endl;
                thread_sched_.add(sched.clock() + int64_t(delay), sched.thread_id(), sched.place_id());
                std::cerr << "Added to schedule." << std::endl;
            }
        } else if (status == 0) {
            // Successfully ran to completion.  Remove from thread table.
            std::cerr << "Thread ran to completion." << std::endl;
            LS.rawset(threads, sched.thread_id(), LuaNil);
        } else {
            // Generated an error.  Add a traceback, print, and kill the coroutine.
            traceback_coroutine(CO);
            std::cerr << lua_tostring(CO, -1);
            LS.rawset(threads, sched.thread_id(), LuaNil);
        }
    }
    LS.result();
    assert(stack_is_clear());
}

void World::serialize(StreamBuffer *sb) {
    assert(stack_is_clear());
    assert(redirects_.empty());
    int64_t wc0 = sb->write_count();
    lua_snap_.serialize(sb);
    id_global_pool_.serialize(sb);
    thread_sched_.serialize(sb);
    sb->write_size(tangibles_.size());
    for (const auto &p : tangibles_) {
        sb->write_int64(p.first);
        p.second->serialize(sb);
    }
    int64_t wc1 = sb->write_count();
    std::cerr << "World serialized to " << wc1-wc0 << " bytes." << std::endl;
    assert(stack_is_clear());
}

void World::deserialize(StreamBuffer *sb) {
    assert(stack_is_clear());
    redirects_.clear();
    lua_snap_.deserialize(sb);
    id_global_pool_.deserialize(sb);
    thread_sched_.deserialize(sb);
    // Mark all tangibles for deletion by setting ID to zero.
    for (const auto &p : tangibles_) {
        p.second->plane_item_.set_id(0);
    }
    // Deserialize tangibles.
    size_t ntan = sb->read_size();
    for (size_t i = 0; i < ntan; i++) {
        int64_t id = sb->read_int64();
        std::unique_ptr<Tangible> &t = tangibles_[id];
        if (t == nullptr) {
            t.reset(new Tangible(this, id));
        } else {
            t->plane_item_.set_id(id);
        }
        t->deserialize(sb);
    }
    // Delete tangibles that didn't get deserialized.
    for (auto iter = tangibles_.begin(); iter != tangibles_.end(); ) {
        if (iter->second->plane_item_.id() == 0) {
            tangibles_.erase(iter++);
        } else {
            ++iter;
        }
    }
    assert(stack_is_clear());
}

void World::snapshot() {
    snapshot_.clear();
    serialize(&snapshot_);
}

void World::rollback() {
    assert(!snapshot_.at_eof());
    deserialize(&snapshot_);
}

LuaDefine(tangible_animstate, "c") {
    LuaArg tanobj;
    LuaRet graphic, plane, x, y, z, facing;
    LuaStack LS(L, tanobj, graphic, plane, x, y, z, facing);
    World *w = World::fetch_global_pointer(L);
    Tangible *tan = w->tangible_get(L, tanobj.index());
    const AnimStep &aqback = tan->anim_queue_.back();
    LS.set(graphic, aqback.graphic());
    LS.set(plane, aqback.plane());
    LS.set(x, aqback.xyz().x);
    LS.set(y, aqback.xyz().y);
    LS.set(z, aqback.xyz().z);
    LS.set(facing, aqback.facing());
    return LS.result();
}

LuaDefine(tangible_animate, "c") {
    LuaArg tanobj, config;
    LuaStack LS(L, tanobj, config);
    World *w = World::fetch_global_pointer(L);
    Tangible *tan = w->tangible_get(L, tanobj.index());
    int64_t id = w->id_global_pool_.alloc_id_for_thread(L);
    AnimStep step;
    step.from_lua(L, config.index());
    if (step.action() == "") {
        luaL_error(L, "animation action must be specified");
    }
    tan->anim_queue_.add(id, step);
    tan->update_plane_item();
    return LS.result();
}

LuaDefine(tangible_setclass, "c") {
    LuaArg tanobj, classname;
    LuaVar classtab, mt;
    LuaStack LS(L, tanobj, classname, classtab, mt);
    World *w = World::fetch_global_pointer(L);
    w->tangible_get(L, tanobj.index());
    LS.getclass(classtab, classname);
    LS.getmetatable(mt, tanobj);
    LS.rawset(mt, "__index", classtab);
    return LS.result();
}

LuaDefine(tangible_delete, "c") {
    // TODO: we need some sanity checks to make sure you're not deleting
    // the current player, or anything like that.
    LuaArg tanobj;
    LuaStack LS(L, tanobj);
    World *w = World::fetch_global_pointer(L);
    Tangible *tan = w->tangible_get(L, tanobj.index());
    w->tangible_delete(L, tan->id());
    return LS.result();
}

LuaDefine(tangible_build, "c") {
    LuaArg config;
    LuaVar classname, classtab, mt;
    LuaRet database;
    LuaStack LS(L, config, classname, classtab, database, mt);
    
    LS.checktable(config);
    // Get the class of the new tangible.
    LS.rawget(classname, config, "class");
    if (LS.isnil(classname)) {
        luaL_error(L, "must specify a class name");
    }
    LS.getclass(classtab, classname);

    // Parse the initial animation step.
    AnimStep initstep;
    initstep.from_lua(L, config.index());
    if (!initstep.has_xyz()) {
        luaL_error(L, "You must specify (X,Y,Z) for new tangible");
    }
    if (!initstep.has_plane()) {
        luaL_error(L, "You must specify plane for new tangible");
    }
    if (!initstep.has_graphic()) {
        luaL_error(L, "You must specify graphic for new tangible");
    }

    // TODO: generate error if there's extra crap in the config table.

    World *w = World::fetch_global_pointer(L);
    Tangible *tan = w->tangible_make(L, 0, true);
    lua_replace(L, database.index());

    // Update the class of the new tangible.
    LS.getmetatable(mt, database);
    LS.rawset(mt, "__index", classtab);

    // Update the animation queue and planemap of the new tangible.
    int64_t stepid = w->id_global_pool_.alloc_id_for_thread(L);
    tan->anim_queue_.add(stepid, initstep);
    tan->update_plane_item();

    return LS.result();
}

LuaDefine(tangible_get, "c") {
    LuaArg id;
    LuaVar tangibles;
    LuaRet database;
    LuaStack LS(L, id, tangibles, database);
    int64_t nid = LS.ckinteger(id);
    LS.rawget(tangibles, LuaRegistry, "tangibles");
    LS.rawget(database, tangibles, id);
    if (!LS.istable(database)) {
        luaL_error(L, "Not a tangible ID: %d", nid);
    }
    return LS.result();
}

LuaDefine(tangible_redirect, "c") {
    LuaArg actor1, actor2;
    LuaStack LS(L, actor1, actor2);
    World *w = World::fetch_global_pointer(L);
    Tangible *tan1 = w->tangible_get(L, actor1.index());
    Tangible *tan2 = w->tangible_get(L, actor2.index());
    w->redirects_[tan1->id()] = tan2->id();
    return LS.result();
}

LuaDefine(world_wait, "f") {
    if ((lua_gettop(L) != 1) || (lua_type(L, -1) != LUA_TNUMBER)) {
        luaL_error(L, "Argument to wait must be a number.");
    }
    return lua_yield(L, 1);
}

LuaDefine(world_getregistry, "f") {
    lua_pushvalue(L, LUA_REGISTRYINDEX);
    return 1;
}