#include "texture.h"
#include "arena.h"
#include "memory.h"
#include "json.h"
#include "renderer.h"
#include "util.h"
#include "asset_cache.h"
#include "sys.h"
#include "scratch.h"
#include "resource.h"
#include "ase.h"
#include "log.h"

#define LOOKUP_TABLE_CAPACITY_FACTOR 2.0f

struct texture_task_params {
    struct texture_task_params *next_free;

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

struct texture_task_params_store {
    struct texture_task_params *head_free;
    struct arena arena;
    struct sys_mutex mutex;
};

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

GLOBAL struct {
    struct texture_task_params_store params;
} L = { 0 } DEBUG_LVAR(L_texture);

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

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

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

INTERNAL struct texture_task_params *texture_task_params_alloc(void)
{
    struct texture_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 texture_task_params);
        }
        sys_mutex_unlock(&L.params.mutex);
    }
    return p;
}

INTERNAL void texture_task_params_release(struct texture_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);
}

/* ========================== *
 * Default texture load
 * ========================== */

#define DEFAULT_TEXTURE_NAME "__texture_default"

INTERNAL struct image_rgba generate_purple_black_image(struct arena *arena, u32 width, u32 height)
{
    u32 *pixels = arena_push_array(arena, u32, width * height);

    /* Create texture containing alternating blocks of purple and black */
    u32 color_size = 4;
    u32 color_1 = 0xFFDC00FF;
    u32 color_2 = 0xFF000000;
    for (u32 x = 0; x < width; ++x) {
        for (u32 y = 0; y < height; ++y) {
            u32 pixel_index = x + width * y;
            if ((y / color_size) % 2 == 0) {
                if ((x / color_size) % 2 == 0) {
                    pixels[pixel_index] = color_1;
                } else {
                    pixels[pixel_index] = color_2;
                }
            } else {
                if ((x / color_size) % 2 == 0) {
                    pixels[pixel_index] = color_2;
                } else {
                    pixels[pixel_index] = color_1;
                }
            }
        }
    }

    return (struct image_rgba) {
        .width = width,
        .height = height,
        .pixels = pixels
    };
}

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

INTERNAL void texture_load_asset_task(void *vparams)
{
    __prof;
    struct texture_task_params *params = (struct texture_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 texture \"%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 texture_rs = resource_open(path);
        struct ase_decode_image_result decoded = ase_decode_image(scratch.arena, texture_rs.bytes);
        resource_close(texture_rs);

        /* Failure paths */
        if (!decoded.valid) {
            if (decoded.error_msg.len > 0) {
                error_msg = decoded.error_msg;
            }
            goto abort;
        } else if (decoded.image.width > RENDERER_TEXTURE_MAX_WIDTH || decoded.image.height > RENDERER_TEXTURE_MAX_HEIGHT) {
            error_msg = string_format(scratch.arena,
                                      STR("Image with dimensions %F x %F exceeds maximum allowed dimensions (%F x %F)"),
                                      FMT_UINT(decoded.image.width),
                                      FMT_UINT(decoded.image.height),
                                      FMT_UINT(RENDERER_TEXTURE_MAX_WIDTH),
                                      FMT_UINT(RENDERER_TEXTURE_MAX_HEIGHT));
            goto abort;
        } else {
            success = true;
        }

        struct image_rgba image_data = decoded.image;

        /* Create renderer texture */
        struct renderer_handle handle = renderer_texture_alloc(image_data);

        /* Initialize texture & its data into store */
        struct texture *texture = NULL;
        {
            struct asset_cache_store store = asset_cache_store_open();
            texture = arena_push(store.arena, struct texture);
            *texture = (struct texture) {
                .width = image_data.width,
                .height = image_data.height,
                .renderer_handle = handle
            };
            asset_cache_store_close(&store);
        }

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

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

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

        /* Generate purple & black image */
        struct renderer_handle handle = { 0 };
        struct image_rgba default_image_data = generate_purple_black_image(scratch.arena, 64, 64);
        handle = renderer_texture_alloc(default_image_data);

        /* Store */
        struct texture *texture = NULL;
        {
            struct asset_cache_store store = asset_cache_store_open();
            texture = arena_push(store.arena, struct texture);
            *texture = (struct texture) {
                .width = default_image_data.width,
                .height = default_image_data.height,
                .renderer_handle = handle
            };
            asset_cache_store_close(&store);
        }

        asset_cache_mark_ready(asset, texture);
    }

    texture_task_params_release(params);

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

struct asset *texture_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("_tex"));
    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 texture_task_params *params = texture_task_params_alloc();
        if (path.len > (sizeof(params->path_cstr) - 1)) {
            sys_panic(string_format(scratch.arena,
                                    STR("Texture 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(&texture_load_asset_task, params, WORK_PRIORITY_NORMAL);
        } else {
            wh = work_push_task(&texture_load_asset_task, params, WORK_PRIORITY_NORMAL);
        }
        asset_cache_set_work(asset, &wh);
    }

    scratch_end(scratch);
    return asset;
}

struct texture *texture_load_async(struct string path)
{
    __prof;
    struct asset *asset = texture_load_asset(path, false);
    struct texture *tex = (struct texture *)asset_cache_get_store_data(asset);
    return tex;
}


struct texture *texture_load(struct string path)
{
    __prof;
    struct asset *asset = texture_load_asset(path, true);
    asset_cache_wait(asset);
    struct texture *tex = (struct texture *)asset_cache_get_store_data(asset);
    return tex;
}