#include "sheet.h"
#include "arena.h"
#include "log.h"
#include "sys.h"
#include "scratch.h"
#include "resource.h"
#include "asset_cache.h"
#include "ase.h"
#include "util.h"

struct sheet_task_params {
    struct sheet_task_params *next_free;

    struct asset *asset;
    u64 path_len;
    char path_cstr[1024];
};

struct sheet_task_params_store {
    struct sheet_task_params *head_free;
    struct arena arena;
    struct sys_mutex mutex;
};

/* ========================== *
 * Global state
 * ========================== */

GLOBAL struct {
    struct sheet_task_params_store params;
} L = { 0 }, DEBUG_LVAR(L_sheet);


/* ========================== *
 * Startup
 * ========================== */

void sheet_startup(void)
{
    L.params.arena = arena_alloc(GIGABYTE(64));
    L.params.mutex = sys_mutex_alloc();
}

/* ========================== *
 * Load task param store
 * ========================== */

INTERNAL struct sheet_task_params *sheet_task_params_alloc(void)
{
    struct sheet_task_params *p = NULL;
    sys_mutex_lock(&L.params.mutex);
    {
        if (L.params.head_free) {
            p = L.params.head_free;
            L.params.head_free = p->next_free;
        } else {
            p = arena_push_zero(&L.params.arena, struct sheet_task_params);
        }
    }
    sys_mutex_unlock(&L.params.mutex);
    return p;
}

INTERNAL void sheet_task_params_release(struct sheet_task_params *p)
{
    sys_mutex_lock(&L.params.mutex);
    {
        p->next_free = L.params.head_free;
        L.params.head_free = p;
    }
    sys_mutex_unlock(&L.params.mutex);
}

/* ========================== *
 * Init
 * ========================== */

#define SHEET_LOOKUP_TABLE_CAPACITY_FACTOR 2.0

INTERNAL struct sheet sheet_from_ase(struct arena *arena, struct ase_decode_sheet_result ase)
{
    struct sheet sheet = { 0 };

    ASSERT(ase.num_frames >= 1);

    /* Init frames */
    sheet.image_size = ase.image_size;
    sheet.frame_size = ase.frame_size;
    sheet.frames = arena_push_array_zero(arena, struct sheet_frame, ase.num_frames);
    sheet.frames_count = ase.num_frames;
    for (struct ase_frame *ase_frame = ase.frame_head; ase_frame; ase_frame = ase_frame->next) {
        u32 index = ase_frame->index;
        sheet.frames[index] = (struct sheet_frame) {
            .index = index,
            .duration = ase_frame->duration,
            .clip = ase_frame->clip
        };
    }

    /* Init tags */
    sheet.tags_count = ase.num_tags;
    if (ase.num_tags > 0) {
        sheet.tags_dict = fixed_dict_init(arena, (u64)(ase.num_tags * SHEET_LOOKUP_TABLE_CAPACITY_FACTOR));
        for (struct ase_tag *ase_tag = ase.tag_head; ase_tag; ase_tag = ase_tag->next) {
            struct string name = string_copy(arena, ase_tag->name);
            struct sheet_tag *tag = arena_push(arena, struct sheet_tag);
            *tag = (struct sheet_tag) {
                .name = name,
                .start = ase_tag->start,
                .end = ase_tag->end
            };
            fixed_dict_set(arena, &sheet.tags_dict, name, tag);
        }

    }

    return sheet;
}

INTERNAL struct sheet sheet_default(struct arena *arena)
{
    struct sheet sheet = { 0 };
    sheet.frames_count = 1;
    sheet.frames = arena_push(arena, struct sheet_frame);
    sheet.frames[0] = (struct sheet_frame) {
        .index = 0,
        .duration = 0,
        .clip = CLIP_ALL
    };
    return sheet;
}

/* ========================== *
 * Load
 * ========================== */

INTERNAL WORK_TASK_FUNC_DEF(sheet_load_asset_task, vparams)
{
    __prof;
    struct sheet_task_params *params = (struct sheet_task_params *)vparams;
    struct temp_arena scratch = scratch_begin_no_conflict();
    struct string path = string_from_cstr_len(params->path_cstr, params->path_len);
    struct asset *asset = params->asset;

    logf_info("Loading sheet \"%F\"", FMT_STR(path));
    sys_timestamp_t start_ts = sys_timestamp();

    b32 success = false;
    struct string error_msg = STR("Unknown error");

    ASSERT(string_ends_with(path, STR(".ase")));
    if (resource_exists(path)) {
        /* Decode */
        struct resource sheet_rs = resource_open(path);
        struct ase_decode_sheet_result decoded = ase_decode_sheet(scratch.arena, sheet_rs.bytes);
        resource_close(sheet_rs);

        /* Failure paths */
        if (!decoded.valid) {
            if (decoded.error_msg.len > 0) {
                error_msg = decoded.error_msg;
            }
            goto abort;
        } else {
            success = true;
        }

        /* Initialize sheet & its data into store */
        struct sheet *sheet = NULL;
        {
            struct asset_cache_store store = asset_cache_store_open();
            sheet = arena_push(store.arena, struct sheet);
            *sheet = sheet_from_ase(store.arena, decoded);
            asset_cache_store_close(&store);
        }

        logf_info("Finished loading sheet \"%F\" in %F seconds",
                  FMT_STR(path),
                  FMT_FLOAT(sys_timestamp_seconds(sys_timestamp() - start_ts)));

        asset_cache_mark_ready(asset, sheet);
    } else {
        success = false;
        error_msg = STR("Resource not found");
        goto abort;
    }

abort:
    if (!success) {
        logf_error("Error loading sheet \"%F\": %F", FMT_STR(path), FMT_STR(error_msg));

        /* Store */
        struct sheet *sheet = NULL;
        {
            struct asset_cache_store store = asset_cache_store_open();
            sheet = arena_push(store.arena, struct sheet);
            *sheet = sheet_default(store.arena);
            asset_cache_store_close(&store);
        }

        asset_cache_mark_ready(asset, sheet);
    }

    sheet_task_params_release(params);

    /* Decommit decoded sheet data */
    scratch_end_and_decommit(scratch);
}

struct asset *sheet_load_asset(struct string path, b32 help)
{
    __prof;
    struct temp_arena scratch = scratch_begin_no_conflict();

    struct string key = string_cat(scratch.arena, path, STR("_sheet"));
    u64 hash = asset_cache_hash(key);
    b32 is_first_touch;
    struct asset *asset = asset_cache_touch(key, hash, &is_first_touch);

    if (is_first_touch) {
        /* Assemble task params */
        struct sheet_task_params *params = sheet_task_params_alloc();
        if (path.len > (sizeof(params->path_cstr) - 1)) {
            sys_panic(string_format(scratch.arena,
                                    STR("Sheet path \"%F\" too long!"),
                                    FMT_STR(path)));
        }
        string_to_cstr_buff(path, BUFFER_FROM_ARRAY(params->path_cstr));
        params->path_len = path.len;
        params->asset = asset;

        /* Push task */
        asset_cache_mark_loading(asset);
        struct work_handle wh = { 0 };
        if (help) {
            wh = work_push_task_and_help(&sheet_load_asset_task, params, WORK_PRIORITY_NORMAL);
        } else {
            wh = work_push_task(&sheet_load_asset_task, params, WORK_PRIORITY_NORMAL);
        }
        asset_cache_set_work(asset, &wh);
    }

    scratch_end(scratch);
    return asset;
}

struct sheet *sheet_load_async(struct string path)
{
    __prof;
    struct asset *asset = sheet_load_asset(path, false);
    struct sheet *sheet = (struct sheet *)asset_cache_get_store_data(asset);
    return sheet;
}


struct sheet *sheet_load(struct string path)
{
    __prof;
    struct asset *asset = sheet_load_asset(path, true);
    asset_cache_wait(asset);
    struct sheet *sheet = (struct sheet *)asset_cache_get_store_data(asset);
    return sheet;
}

/* ========================== *
 * Sheet data
 * ========================== */

GLOBAL READONLY struct sheet_tag g_default_tag = { 0 };

struct sheet_tag sheet_get_tag(struct sheet *sheet, struct string name)
{
    struct sheet_tag res = g_default_tag;
    if (sheet->tags_count > 0) {
        struct sheet_tag *entry = fixed_dict_get(&sheet->tags_dict, name);
        if (entry) {
            res = *entry;
        }
    }
    return res;
}

struct sheet_frame sheet_get_frame(struct sheet *sheet, u32 index)
{
    index = min_u32(sheet->frames_count - 1, index);
    return sheet->frames[index];
}