#include <stdio.h>
#include <stdint.h>
#include <SDL3/SDL.h>
#include <imgui.h>
#include <imgui_internal.h>
#include <imgui_impl_sdl3.h>
#include <imgui_impl_sdlgpu3.h>

#include "smol-atlas.h"
#include "defer.h"
#include "log.h"
#include "m_string.h"
#include "math_graphics.h"
#include "load_entire_file.h"
#include "stb_image.h"
#include "../assets/shader/basic_vertex_shader.h"
#include "../assets/shader/basic_pixel_shader.h"

using namespace M;

SDL_GPUDevice *device;
SDL_Window    *window;

SDL_GPUShader *basic_vertex_shader;
SDL_GPUShader *basic_pixel_shader;

SDL_GPUGraphicsPipeline *basic_graphics_pipeline;
SDL_GPUSampler 			*point_sampler;

SDL_GPUBuffer *vertex_buffer;
SDL_GPUBuffer *index_buffer;
SDL_GPUBuffer *tiles_instance_buffer;
SDL_GPUBuffer *player_instance_buffer;

Sint32 window_width;
Sint32 window_height;

bool Running = true;

#define view_width 16
#define view_height 9

struct Vertex {
    V4 pos;
    V2 uv0uv1;
};

Vertex vertices[] = {
    {{ -1,  1, 1, 1 }, {0, 0}},
    {{  1, -1, 1, 1 }, {1, 1}},
    {{ -1, -1, 1, 1 }, {0, 1}},
    {{  1,  1, 1, 1 }, {1, 0}},
};

Uint16 indices[] = {
    0, 1, 2,
    0, 3, 1,
};

struct Instance {
    V4 pos_size;
    Uint32 tile_type;
    V4 uv0uv1;
};

Instance tiles_instances[view_width * view_height] = {

};

Instance player_instance = { { 0.5f + 0.5f / view_width, 0.5f, 1.0f / view_width, 1.0f / view_height}, 0, {0, 0, 1, 1}};

Uint32 map_width = view_width;
Uint32 map_height = view_height;

Uint32* map_tiles;

struct Player {
    Sint64 pos_x;
    Sint64 pos_y;
};

Player player = {
    .pos_x = 8,
    .pos_y = 6,
};

struct PerFrame {
    float aspect_ratio;
    float empty[3];
};

PerFrame per_frame = {1};

typedef struct {
    Uint32      type;
    const char *asset_path;

    smol_atlas_item_t *atlas_item;
} TileInfo;

TileInfo tile_infos[] = {
    { 0x0001, "../assets/tiles/error.png" },
    { 0x0000, "../assets/tiles/empty.png" },
    { 0x0100, "../assets/tiles/grass_1.png" },
    { 0x0101, "../assets/tiles/grass_2.png" },
    { 0x0102, "../assets/tiles/grass_3.png" },
    { 0x0200, "../assets/tiles/ground_1.png" },
    { 0x0300, "../assets/tiles/water_1.png" },
    { 0x0301, "../assets/tiles/water_2.png" },
};

int tile_atlas_size = 256;
smol_atlas_t *tile_atlas;

Sint32 selected_tile = -1;

void save_map() {
    log("Save file is under construction.");
    FILE* file = fopen("../assets/map/map.sv", "wb");

    if (!file) {
        log_error("Save file creation has failed.");
        return;
    }
    defer(fclose(file));

    if (fwrite(&map_width, sizeof(Uint32), 1, file) != 1) {
        log_error("fwrite for map_width has failed.");
        return;
    }	

    if (fwrite(&map_height, sizeof(Uint32), 1, file) != 1) {
        log_error("fwrite for map_height has failed.");
        return;
    }

    for (int i = 0; i < map_width * map_height; i++) {
        Uint32 type = tile_infos[map_tiles[i]].type;
        if (fwrite(&type, sizeof(Uint32), 1, file) != 1) {
            log_error("fwrite for tile_type at tile number %d has failed.", i);
            return;
        }
    }

    log("Saving map was successful.");
}

void load_map() {
    log("Load save file.");
    String file = load_entire_file("../assets/map/map.sv");
    if (!file.length) {
        log_error("Loading save file has failed.");
        return;
    }

    map_width = read<Uint32>(file);
    map_height = read<Uint32>(file);
    if (file.length != map_width * map_height * sizeof(Uint32)) {
        log_error("Incorrect file.length.");
        return;
    }

    if (map_tiles)
        free(map_tiles);

    map_tiles = (Uint32*)malloc(map_width * map_height * sizeof(Uint32));

    for (int i = 0; i < map_width * map_height; i++) {
        Uint32 type = read<Uint32>(file);
        Uint32 kind = 0;
        for (int i = 0; i < SDL_arraysize(tile_infos); i++) {
            if (tile_infos[i].type == type) {
                kind = i;
                break;
            }
        }

        map_tiles[i] = kind;
    }

    log("Loading map was successful.");
}

void change_map_size(char direction, int amount) {
    Uint32* old_map = map_tiles;
    auto old_map_width = map_width;
    auto old_map_height = map_height;

    Sint32 new_x_offset = 0;
    Sint32 new_y_offset = 0;
    Sint32 old_x_offset = 0;
    Sint32 old_y_offset = 0;

    Sint32 to_fill_width = map_width;
    Sint32 to_fill_height = map_height;
    Sint32 to_fill_x_offset = 0;
    Sint32 to_fill_y_offset = 0;

    if (direction == 'W') {
        player.pos_x = player.pos_x + amount;
        map_width += amount;
        to_fill_width = amount;
        
        if (amount < 0) 
            old_x_offset = -amount;
        else 
            new_x_offset = amount;
    }

    if (direction == 'N') {
        player.pos_y = player.pos_y + amount;
        map_height += amount;
        to_fill_height = amount;

        if (amount < 0)
            old_y_offset = -amount;
        else 
            new_y_offset = amount;
    }

    if (direction == 'E') {
        map_width += amount;
        to_fill_width = amount;
        to_fill_x_offset = old_map_width;
    }

    if (direction == 'S') {
        map_height += amount;
        to_fill_height = amount;
        to_fill_y_offset = old_map_height;
    }

    map_tiles = (Uint32*)malloc(map_width * map_height * sizeof(Uint32));

    for (int y = 0; y < min(old_map_height, map_height); y++) {
        for (int x = 0; x < min(old_map_width, map_width); x++) {
            map_tiles[(y + new_y_offset) * map_width + (x + new_x_offset)] = old_map[(y + old_y_offset) * old_map_width + (x + old_x_offset)];
        }
    }

    for (int y = 0; y < to_fill_height; y++) {
        for (int x = 0; x < to_fill_width; x++) {
                map_tiles[(y + to_fill_y_offset) * map_width + (x + to_fill_x_offset)] = 0;
        }
    }

    player.pos_x = clamp(0, player.pos_x, map_width - 1);
    player.pos_y = clamp(0, player.pos_y, map_height - 1);

    free(old_map);
}

bool update_buffer(SDL_GPUBuffer *buffer, Uint32 offset, Uint32 num_bytes, void *data) {
    SDL_GPUTransferBufferCreateInfo	transfer_buffer_info = {
        .usage = SDL_GPU_TRANSFERBUFFERUSAGE_UPLOAD,
        .size  = num_bytes,
    };

    SDL_GPUTransferBuffer *transfer_buffer = SDL_CreateGPUTransferBuffer(device, &transfer_buffer_info);
    if (!transfer_buffer) {
        log_error("Failed to create gpu transfer buffer (%s).", SDL_GetError());
        return false;
    }

    void *transfer_data = SDL_MapGPUTransferBuffer(device, transfer_buffer, true);
    if (!transfer_data) {
        log_error("Failed to map gpu transfer buffer (%s).", SDL_GetError());
        SDL_ReleaseGPUTransferBuffer(device, transfer_buffer);
        return false;
    }
    memcpy(transfer_data, data, num_bytes);
    SDL_UnmapGPUTransferBuffer(device, transfer_buffer);

    SDL_GPUCommandBuffer *command_buffer = SDL_AcquireGPUCommandBuffer(device);
    if (!command_buffer) {
        log_error("Failed to acquire gpu command buffer (%s).", SDL_GetError());
        SDL_ReleaseGPUTransferBuffer(device, transfer_buffer);
        return false;
    }

    SDL_GPUTransferBufferLocation transfer_info = {
        .transfer_buffer = transfer_buffer,
        .offset  		 = 0,
    };

    SDL_GPUBufferRegion buffer_region = {
        .buffer = buffer,
        .offset = offset,
        .size   = num_bytes,
    };

    SDL_GPUCopyPass *copy_pass = SDL_BeginGPUCopyPass(command_buffer);
    SDL_UploadToGPUBuffer(copy_pass, &transfer_info, &buffer_region, true);
    SDL_EndGPUCopyPass(copy_pass);

    if (!SDL_SubmitGPUCommandBuffer(command_buffer)) {
        log_error("Failed to submit gpu command buffer (%s).", SDL_GetError());
        SDL_ReleaseGPUTransferBuffer(device, transfer_buffer);
        SDL_CancelGPUCommandBuffer(command_buffer);
        return false;
    }

    SDL_ReleaseGPUTransferBuffer(device, transfer_buffer);
    return true;
}

SDL_GPUBuffer *create_buffer(SDL_GPUBufferUsageFlags usage, Uint32 num_bytes, void *data = NULL, const char *name = NULL) {
    SDL_PropertiesID properties = 0;
    if (name) {
        properties = SDL_CreateProperties();
        if (properties) SDL_SetStringProperty(properties, SDL_PROP_GPU_BUFFER_CREATE_NAME_STRING, name);
    }
    
    SDL_GPUBufferCreateInfo buffer_info = {
        .usage = usage,
        .size  = num_bytes,

        .props = properties,
    };

    SDL_GPUBuffer *buffer = SDL_CreateGPUBuffer(device, &buffer_info);
    if (properties) SDL_DestroyProperties(properties);

    if (data) {
        if (!update_buffer(buffer, 0, num_bytes, data)) {
            log_error("Failed to update buffer (%s).", SDL_GetError());
            SDL_ReleaseGPUBuffer(device, buffer);
            return NULL;
        }
    }

    return buffer;
}

SDL_GPUTexture *create_shader_texture(const char *path) {
    int width = 0, height = 0, channels = 0; 
    stbi_uc *data = stbi_load(path, &width, &height, &channels, 0);
    if (!data) {
        log_error("Failed to load texture (\"%s\").", path);
        return NULL;
    }

    SDL_GPUTextureFormat format = SDL_GPU_TEXTUREFORMAT_INVALID;
    if (channels == 1) format = SDL_GPU_TEXTUREFORMAT_A8_UNORM;
    if (channels == 4) format = SDL_GPU_TEXTUREFORMAT_R8G8B8A8_UNORM;

    if (format == SDL_GPU_TEXTUREFORMAT_INVALID) {
        log_error("Failed to find texture format for texture (\"%s\").", path);
        stbi_image_free(data);
        return NULL;
    }

    SDL_PropertiesID properties = SDL_CreateProperties();
    if (properties) SDL_SetStringProperty(properties, SDL_PROP_GPU_TEXTURE_CREATE_NAME_STRING, path);

    SDL_GPUTextureCreateInfo texture_info = {
        .type   = SDL_GPU_TEXTURETYPE_2D,
        .format = format,
        .usage  = SDL_GPU_TEXTUREUSAGE_SAMPLER,
        .width  = (Uint32)width,
        .height = (Uint32)height,

        .layer_count_or_depth = 1,
        .num_levels = 1,

        .props = properties,
    };

    SDL_GPUTexture *texture = SDL_CreateGPUTexture(device, &texture_info);
    if (!texture) {
        log_error("Failed to create gpu texture (%s).", SDL_GetError());
        stbi_image_free(data);
        return NULL;
    }
    if (properties) SDL_DestroyProperties(properties);

    Uint32 upload_size = width * height * channels;
    SDL_GPUTransferBufferCreateInfo	transfer_buffer_info = {
        .usage = SDL_GPU_TRANSFERBUFFERUSAGE_UPLOAD,
        .size  = upload_size,
    };

    SDL_GPUTransferBuffer *transfer_buffer = SDL_CreateGPUTransferBuffer(device, &transfer_buffer_info);
    if (!transfer_buffer) {
        log_error("Failed to create gpu transfer buffer (%s).", SDL_GetError());
        SDL_ReleaseGPUTexture(device, texture);
        stbi_image_free(data);
        return NULL;
    }

    void *transfer_data = SDL_MapGPUTransferBuffer(device, transfer_buffer, false);
    if (!transfer_data) {
        log_error("Failed to map gpu transfer buffer (%s).", SDL_GetError());
        SDL_ReleaseGPUTransferBuffer(device, transfer_buffer);
        SDL_ReleaseGPUTexture(device, texture);
        stbi_image_free(data);
        return NULL;
    }
    memcpy(transfer_data, data, upload_size);
    SDL_UnmapGPUTransferBuffer(device, transfer_buffer);
    stbi_image_free(data);

    SDL_GPUTextureTransferInfo transfer_info = {
        .transfer_buffer = transfer_buffer,
        .pixels_per_row  = (Uint32)width,
    };

    SDL_GPUTextureRegion tetxure_region = {
        .texture = texture,
        .w = (Uint32)width,
        .h = (Uint32)height,
        .d = 1,
    };

    SDL_GPUCommandBuffer *command_buffer = SDL_AcquireGPUCommandBuffer(device);
    if (!command_buffer) {
        log_error("Failed to acquire gpu command buffer (%s).", SDL_GetError());
        SDL_ReleaseGPUTransferBuffer(device, transfer_buffer);
        SDL_ReleaseGPUTexture(device, texture);
        return NULL;
    }

    SDL_GPUCopyPass *copy_pass = SDL_BeginGPUCopyPass(command_buffer);
    SDL_UploadToGPUTexture(copy_pass, &transfer_info, &tetxure_region, false);
    SDL_EndGPUCopyPass(copy_pass);

    if (!SDL_SubmitGPUCommandBuffer(command_buffer)) {
        log_error("Failed to submit gpu command buffer (%s).", SDL_GetError());
        SDL_ReleaseGPUTransferBuffer(device, transfer_buffer);
        SDL_ReleaseGPUTexture(device, texture);
        SDL_CancelGPUCommandBuffer(command_buffer);
        return NULL;
    }

    SDL_ReleaseGPUTransferBuffer(device, transfer_buffer);
    return texture;
}

SDL_GPUTexture *create_shader_texture(const char *name, const char *data, int width, int height, int channels) {
    SDL_GPUTextureFormat format = SDL_GPU_TEXTUREFORMAT_INVALID;
    if (channels == 1) format = SDL_GPU_TEXTUREFORMAT_A8_UNORM;
    if (channels == 4) format = SDL_GPU_TEXTUREFORMAT_R8G8B8A8_UNORM;

    if (format == SDL_GPU_TEXTUREFORMAT_INVALID) {
        log_error("Failed to find texture format for texture.");
        return NULL;
    }

    SDL_PropertiesID properties = SDL_CreateProperties();
    if (properties) SDL_SetStringProperty(properties, SDL_PROP_GPU_TEXTURE_CREATE_NAME_STRING, name);

    SDL_GPUTextureCreateInfo texture_info = {
        .type   = SDL_GPU_TEXTURETYPE_2D,
        .format = format,
        .usage  = SDL_GPU_TEXTUREUSAGE_SAMPLER,
        .width  = (Uint32)width,
        .height = (Uint32)height,

        .layer_count_or_depth = 1,
        .num_levels = 1,

        .props = properties,
    };

    SDL_GPUTexture *texture = SDL_CreateGPUTexture(device, &texture_info);
    if (!texture) {
        log_error("Failed to create gpu texture (%s).", SDL_GetError());
        return NULL;
    }
    if (properties) SDL_DestroyProperties(properties);

    Uint32 upload_size = width * height * channels;
    SDL_GPUTransferBufferCreateInfo	transfer_buffer_info = {
        .usage = SDL_GPU_TRANSFERBUFFERUSAGE_UPLOAD,
        .size  = upload_size,
    };

    SDL_GPUTransferBuffer *transfer_buffer = SDL_CreateGPUTransferBuffer(device, &transfer_buffer_info);
    if (!transfer_buffer) {
        log_error("Failed to create gpu transfer buffer (%s).", SDL_GetError());
        SDL_ReleaseGPUTexture(device, texture);
        return NULL;
    }

    void *transfer_data = SDL_MapGPUTransferBuffer(device, transfer_buffer, false);
    if (!transfer_data) {
        log_error("Failed to map gpu transfer buffer (%s).", SDL_GetError());
        SDL_ReleaseGPUTransferBuffer(device, transfer_buffer);
        SDL_ReleaseGPUTexture(device, texture);
        return NULL;
    }
    memcpy(transfer_data, data, upload_size);
    SDL_UnmapGPUTransferBuffer(device, transfer_buffer);

    SDL_GPUTextureTransferInfo transfer_info = {
        .transfer_buffer = transfer_buffer,
        .pixels_per_row  = (Uint32)width,
    };

    SDL_GPUTextureRegion tetxure_region = {
        .texture = texture,
        .w = (Uint32)width,
        .h = (Uint32)height,
        .d = 1,
    };

    SDL_GPUCommandBuffer *command_buffer = SDL_AcquireGPUCommandBuffer(device);
    if (!command_buffer) {
        log_error("Failed to acquire gpu command buffer (%s).", SDL_GetError());
        SDL_ReleaseGPUTransferBuffer(device, transfer_buffer);
        SDL_ReleaseGPUTexture(device, texture);
        return NULL;
    }

    SDL_GPUCopyPass *copy_pass = SDL_BeginGPUCopyPass(command_buffer);
    SDL_UploadToGPUTexture(copy_pass, &transfer_info, &tetxure_region, false);
    SDL_EndGPUCopyPass(copy_pass);

    if (!SDL_SubmitGPUCommandBuffer(command_buffer)) {
        log_error("Failed to submit gpu command buffer (%s).", SDL_GetError());
        SDL_ReleaseGPUTransferBuffer(device, transfer_buffer);
        SDL_ReleaseGPUTexture(device, texture);
        SDL_CancelGPUCommandBuffer(command_buffer);
        return NULL;
    }

    SDL_ReleaseGPUTransferBuffer(device, transfer_buffer);
    return texture;
}

void blit(char *dst, Sint32 dst_width, Sint32 dst_x, Sint32 dst_y, char *src, Sint32 width, Sint32 height, int components = 4) {
    for (Sint32 y = 0; y < height; y++)
        memmove(&dst[((dst_y + y) * dst_width + dst_x) * components], &src[y * width * components], width * components);
}

bool SelectableImage(const char *label, bool selected, SDL_GPUTextureSamplerBinding *image, const ImVec2& image_size, const ImVec2& uv0 = ImVec2(0, 0), const ImVec2& uv1 = ImVec2(1, 1)) {
    const ImGuiContext *context = ImGui::GetCurrentContext();
    const ImVec2 padding = context->Style.FramePadding;

    bool pressed = ImGui::Selectable(label, selected, 0, image_size + padding * 2.0f);

    ImVec2 min = ImGui::GetItemRectMin();
    ImVec2 max = ImGui::GetItemRectMax();
    
    if (image)
        context->CurrentWindow->DrawList->AddImage((ImTextureID)image, min + padding, max - padding, uv0, uv1);

    return pressed;
}

int main(int argc, char **argv) {
    if (!SDL_Init(SDL_INIT_VIDEO | SDL_INIT_EVENTS)) {
        log_error("Failed to initialize SDL (%s). Exiting.", SDL_GetError());
        return 1;
    }

    device = SDL_CreateGPUDevice(SDL_GPU_SHADERFORMAT_SPIRV, true, NULL);
    if (!device) {
        log_error("Failed to create gpu device (%s). Exiting.", SDL_GetError());
        return 1;
    }
    SDL_SetGPUAllowedFramesInFlight(device, 1);
    
    window = SDL_CreateWindow("Mikemon", 1280, 720, SDL_WINDOW_RESIZABLE);
    if (!window) {
        log_error("Failed to create window (%s). Exiting.", SDL_GetError());
        return 1;
    }

    if (!SDL_ClaimWindowForGPUDevice(device, window)) {
        log_error("Failed to claim window for gpu device (%s). Exiting.", SDL_GetError());
        return 1;
    }
    SDL_SetGPUSwapchainParameters(device, window, SDL_GPU_SWAPCHAINCOMPOSITION_SDR, SDL_GPU_PRESENTMODE_VSYNC);

    SDL_GPUShaderCreateInfo basic_vertex_shader_info = {
        .code_size  = SDL_arraysize(SPIRV_basic_vertex_shader),
        .code       = SPIRV_basic_vertex_shader,
        .entrypoint = "main",
        .format     = SDL_GPU_SHADERFORMAT_SPIRV,
        .stage      = SDL_GPU_SHADERSTAGE_VERTEX,

        .num_uniform_buffers = 1,
    };

    basic_vertex_shader = SDL_CreateGPUShader(device, &basic_vertex_shader_info);
    if (!basic_vertex_shader) {
        log_error("Failed to create basic vertex shader. Exiting.");
        return 1;
    }

    SDL_GPUShaderCreateInfo basic_pixel_shader_info = {
        .code_size  = SDL_arraysize(SPIRV_basic_pixel_shader),
        .code       = SPIRV_basic_pixel_shader,
        .entrypoint = "main",
        .format     = SDL_GPU_SHADERFORMAT_SPIRV,
        .stage      = SDL_GPU_SHADERSTAGE_FRAGMENT,

        .num_samplers = 1,
    };

    basic_pixel_shader = SDL_CreateGPUShader(device, &basic_pixel_shader_info);
    if (!basic_pixel_shader) {
        log_error("Failed to create basic pixel shader. Exiting.");
        return 1;
    }

    SDL_GPUVertexBufferDescription vertex_buffer_descriptions[] = {
        {
            .slot       = 0,
            .pitch      = sizeof(Vertex),
            .input_rate = SDL_GPU_VERTEXINPUTRATE_VERTEX,
        },
        {
            .slot               = 1,
            .pitch              = sizeof(Instance),
            .input_rate         = SDL_GPU_VERTEXINPUTRATE_INSTANCE,
            .instance_step_rate = 1,
        },
    };

    SDL_GPUVertexAttribute vertex_attributes[] = {
        {
            .location    = 0,
            .buffer_slot = 0,
            .format 	 = SDL_GPU_VERTEXELEMENTFORMAT_FLOAT4,
            .offset      = 0,
        },
        {
            .location    = 1,
            .buffer_slot = 0,
            .format 	 = SDL_GPU_VERTEXELEMENTFORMAT_FLOAT2,
            .offset      = 16,
        },
        {
            .location    = 2,
            .buffer_slot = 1,
            .format 	 = SDL_GPU_VERTEXELEMENTFORMAT_FLOAT4,
            .offset      = 0,
        },
        {
            .location    = 3,
            .buffer_slot = 1,
            .format 	 = SDL_GPU_VERTEXELEMENTFORMAT_UINT,
            .offset      = 16,
        },
        {
            .location    = 4,
            .buffer_slot = 1,
            .format 	 = SDL_GPU_VERTEXELEMENTFORMAT_FLOAT4,
            .offset      = 20,
        },
    };

    SDL_GPUColorTargetDescription color_target_descriptions[] = {
        {
            .format      = SDL_GetGPUSwapchainTextureFormat(device, window),
            .blend_state = {
                .src_color_blendfactor = SDL_GPU_BLENDFACTOR_ONE,
                .dst_color_blendfactor = SDL_GPU_BLENDFACTOR_ONE_MINUS_SRC_ALPHA,
                .color_blend_op        = SDL_GPU_BLENDOP_ADD,

                .src_alpha_blendfactor = SDL_GPU_BLENDFACTOR_ONE,
                .dst_alpha_blendfactor = SDL_GPU_BLENDFACTOR_ONE_MINUS_SRC_ALPHA,
                .alpha_blend_op        = SDL_GPU_BLENDOP_ADD,
                
                .enable_blend     = true,
            },
        },
    };

    SDL_GPUGraphicsPipelineCreateInfo basic_graphics_pipeline_info = {
        .vertex_shader      = basic_vertex_shader,
        .fragment_shader    = basic_pixel_shader,
        .vertex_input_state = {
            .vertex_buffer_descriptions = vertex_buffer_descriptions,
            .num_vertex_buffers         = SDL_arraysize(vertex_buffer_descriptions),
            .vertex_attributes          = vertex_attributes,
            .num_vertex_attributes      = SDL_arraysize(vertex_attributes),
        },
        .primitive_type   = SDL_GPU_PRIMITIVETYPE_TRIANGLELIST,
        .rasterizer_state = {
            .fill_mode  = SDL_GPU_FILLMODE_FILL,
            .cull_mode  = SDL_GPU_CULLMODE_BACK,
            .front_face = SDL_GPU_FRONTFACE_CLOCKWISE,
        },
        .target_info = {
            .color_target_descriptions = color_target_descriptions,
            .num_color_targets         = SDL_arraysize(color_target_descriptions),
        },
    };

    basic_graphics_pipeline = SDL_CreateGPUGraphicsPipeline(device, &basic_graphics_pipeline_info);
    if (!basic_graphics_pipeline) {
        log_error("Failed to create basic graphics pipeline. Exiting.");
        return 1;
    }

    for (int y = 0; y < view_height; y++) {
        for (int x = 0; x < view_width; x++) {
            tiles_instances[x + y * view_width].pos_size.zw = { 1.0f / view_width, 1.0f / view_height };
            tiles_instances[x + y * view_width].pos_size.xy = { (float)x / view_width, (float)y / (float)view_height };
            tiles_instances[x + y * view_width].pos_size.xy += tiles_instances[x + y * view_width].pos_size.zw * 0.5f;
            tiles_instances[x + y * view_width].uv0uv1 = { 0, 0, 1, 1 };
        }
    }

    SDL_GPUTexture *player_texture = create_shader_texture("../assets/decorations/strawberry.png");
    if (!player_texture) {
        log_error("Failed to create shader texture. Exiting.");
        return 1;
    }

    tile_atlas = sma_atlas_create(tile_atlas_size, tile_atlas_size);
    char *tile_atlas_texture_cpu = (char *)calloc(1, tile_atlas_size * tile_atlas_size * 4);
    for (int i = 0; i < SDL_arraysize(tile_infos); i++) {
        int width = 0, height = 0;  
        stbi_uc *data = stbi_load(tile_infos[i].asset_path, &width, &height, NULL, 4);
        if (!data) {
            log_error("Failed to load texture (\"%s\"). Exiting.", tile_infos[i].asset_path);
            return 1;
        }

        tile_infos[i].atlas_item = sma_item_add(tile_atlas, width, height);
        if (!tile_infos[i].atlas_item) {
            log_error("Failed to add tile texture to atlas. Exiting.");
            return 1;
        }

        blit(tile_atlas_texture_cpu, tile_atlas_size, sma_item_x(tile_infos[i].atlas_item), sma_item_y(tile_infos[i].atlas_item), (char *)data, width, height);
        stbi_image_free(data);
    }
    SDL_GPUTexture *tile_atlas_texture = create_shader_texture("tile_atlas", tile_atlas_texture_cpu, tile_atlas_size, tile_atlas_size, 4);
    free(tile_atlas_texture_cpu);
    if (!tile_atlas_texture) {
        log_error("Failed to create tile atlas texture. Exiting.");
        return 1;
    }

    SDL_GPUSamplerCreateInfo point_sampler_info = {
        .min_filter  = SDL_GPU_FILTER_NEAREST,
        .mag_filter  = SDL_GPU_FILTER_NEAREST,
        .mipmap_mode = SDL_GPU_SAMPLERMIPMAPMODE_NEAREST,

        .address_mode_u = SDL_GPU_SAMPLERADDRESSMODE_CLAMP_TO_EDGE,
        .address_mode_v = SDL_GPU_SAMPLERADDRESSMODE_CLAMP_TO_EDGE,
        .address_mode_w = SDL_GPU_SAMPLERADDRESSMODE_CLAMP_TO_EDGE,
    };

    point_sampler = SDL_CreateGPUSampler(device, &point_sampler_info);

    vertex_buffer = create_buffer(SDL_GPU_BUFFERUSAGE_VERTEX, sizeof(vertices), vertices, "vertex_buffer");
    if (!vertex_buffer) {
        log_error("Failed to create buffer. Exiting.");
        return 1;
    }

    index_buffer = create_buffer(SDL_GPU_BUFFERUSAGE_INDEX, sizeof(indices), indices, "index_buffer");
    if (!index_buffer) {
        log_error("Failed to create buffer. Exiting.");
        return 1;
    }

    tiles_instance_buffer = create_buffer(SDL_GPU_BUFFERUSAGE_VERTEX, sizeof(tiles_instances), tiles_instances, "tiles_instance_buffer");
    if (!tiles_instance_buffer) {
        log_error("Failed to create buffer. Exiting.");
        return 1;
    }

    player_instance_buffer = create_buffer(SDL_GPU_BUFFERUSAGE_VERTEX, sizeof(player_instance), &player_instance, "player_instance_buffer");
    if (!player_instance_buffer) {
        log_error("Failed to create buffer. Exiting.");
        return 1;
    }

    load_map();

    IMGUI_CHECKVERSION();
    ImGui::CreateContext();
    ImGuiIO &io = ImGui::GetIO();
    io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;
    io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;

    ImGui::StyleColorsDark();

    ImGui_ImplSDL3_InitForSDLGPU(window);
    ImGui_ImplSDLGPU3_InitInfo imgui_init_info = {
        .Device            = device,
        .ColorTargetFormat = SDL_GetGPUSwapchainTextureFormat(device, window),
        .MSAASamples       = SDL_GPU_SAMPLECOUNT_1,
    };
    ImGui_ImplSDLGPU3_Init(&imgui_init_info);

    bool show_demo_window = true;
    bool first_frame      = true;


    SDL_GetWindowSizeInPixels(window, &window_width, &window_height);

    // MSG Message;
    while (Running) {
        ImGui_ImplSDLGPU3_NewFrame();
        ImGui_ImplSDL3_NewFrame();
        ImGui::NewFrame();

        ImGui::SetNextWindowPos(ImVec2(0, 0));
        ImGui::SetNextWindowSizeConstraints(ImVec2(0, window_height), ImVec2(window_width, window_height));
        ImGui::SetNextWindowSize(ImVec2(0.2 * window_width, window_height), ImGuiCond_FirstUseEver);
        if (ImGui::Begin("Tile Picker", NULL, ImGuiWindowFlags_NoFocusOnAppearing)) {
            if (SelectableImage("##tile", selected_tile == -1, NULL, ImVec2(32, 32))) {
                selected_tile = -1;
            }

            for (int i = 0; i < SDL_arraysize(tile_infos); i++) {
                ImGui::PushID(i);
                SDL_GPUTextureSamplerBinding texture_binding = { .texture = tile_atlas_texture, .sampler = point_sampler };

                ImVec2 uv0 = ImVec2(sma_item_x(tile_infos[i].atlas_item) / (float)tile_atlas_size, sma_item_y(tile_infos[i].atlas_item) / (float)tile_atlas_size);
                ImVec2 uv1 = ImVec2(uv0.x + sma_item_width(tile_infos[i].atlas_item) / (float)tile_atlas_size, uv0.y + sma_item_height(tile_infos[i].atlas_item) / (float)tile_atlas_size);

                float available = ImGui::GetContentRegionAvail().x - ImGui::GetItemRectMax().x;
                if (available >= 32)
                    ImGui::SameLine();

                if (SelectableImage("##tile", selected_tile == i, &texture_binding, ImVec2(32, 32), uv0, uv1)) {
                    selected_tile = i;
                }

                ImGui::PopID();
            }
        }
        ImGui::End();

        if (show_demo_window)
            ImGui::ShowDemoWindow(&show_demo_window);

        if (first_frame) {
            ImGui::SetWindowFocus(NULL);
            first_frame = false;
        }

        SDL_GPUCommandBuffer *command_buffer = SDL_AcquireGPUCommandBuffer(device);
        if (!command_buffer) {
            log_error("Failed to acquire gpu command buffer (%s). Exiting.", SDL_GetError());
            return 1;
        }

        Uint32 width = 0, height = 0;
        SDL_GPUTexture *swapchain_texture = NULL;
        if (!SDL_WaitAndAcquireGPUSwapchainTexture(command_buffer, window, &swapchain_texture, &width, &height)) {
            log_error("Failed to acquire swapchain texture (%s). Exiting.", SDL_GetError());
            SDL_CancelGPUCommandBuffer(command_buffer);
            return 1;
        }

        SDL_Event event;
        while (SDL_PollEvent(&event)) {
            ImGui_ImplSDL3_ProcessEvent(&event);

            switch (event.type) {
                case SDL_EVENT_QUIT: {
                    Running = false;
                } break;

                case SDL_EVENT_WINDOW_PIXEL_SIZE_CHANGED: {
                    window_width  = event.window.data1;
                    window_height = event.window.data2;
                } break;

                case SDL_EVENT_KEY_DOWN: {
                    if (io.WantCaptureKeyboard)
                        continue;

                    if (event.key.key == SDLK_UP || event.key.key == SDLK_W) {
                        player.pos_y = clamp(0, player.pos_y - 1, map_height - 1);
                    }

                    if (event.key.key == SDLK_LEFT || event.key.key == SDLK_A) {
                        player.pos_x = clamp(0, player.pos_x - 1, map_width - 1);
                    }

                    if (event.key.key == SDLK_DOWN || event.key.key == SDLK_S) {
                        player.pos_y = clamp(0, player.pos_y + 1, map_height - 1);
                    }

                    if (event.key.key == SDLK_RIGHT || event.key.key == SDLK_D) {
                        player.pos_x = clamp(0, player.pos_x + 1, map_width - 1);
                    }

                    if (event.key.key == SDLK_F1) {
                        save_map();
                    }

                    if (event.key.key == SDLK_F4) {
                        load_map();
                    }
                } break;

                case SDL_EVENT_MOUSE_BUTTON_DOWN: {
                    if (io.WantCaptureMouse)
                        continue;

                    if (selected_tile == -1)
                        continue;

                    float mouse_x = event.button.x;
                    float mouse_y = event.button.y;

                    V2 X = V2{ -1, 1 };
                    V2 Y = V2{ -1, 1 };

                    float correction_factor = (window_width / (float)window_height) / (16.0 / 9.0);
                    if (correction_factor < 1)
                        Y *= correction_factor;
                    else
                        X /= correction_factor;

                    float m_x = remap(0, window_width, -1, 1, mouse_x); 
                    float m_y = remap(0, window_height, -1, 1, mouse_y); 

                    mouse_x = remap(X.x, X.y, 0, window_width, m_x);
                    mouse_y = remap(Y.x, Y.y, 0, window_height, m_y);

                    float tile_width = window_width / (float) view_width;
                    float tile_height = window_height / (float) view_height;

                    int tile_x = (int)(mouse_x / tile_width) + player.pos_x - (view_width / 2);
                    int tile_y = (int)(mouse_y / tile_height) + player.pos_y - (view_height / 2);

                    if (mouse_x < 0)
                        tile_x = -1;
                    if (mouse_y< 0)
                        tile_y = -1;

                    if(0 <= tile_x && tile_x < map_width && 
                       0 <= tile_y && tile_y < map_height)
                        map_tiles[tile_x + map_width * tile_y] = selected_tile;

                    SDL_Keymod modifiers = SDL_GetModState();
                    if (modifiers & SDL_KMOD_SHIFT && tile_x == -1) {
                        if(modifiers & SDL_KMOD_CTRL)
                            change_map_size('W', -1);
                        else
                            change_map_size('W', 2);
                    }

                    if (modifiers & SDL_KMOD_SHIFT && tile_x == map_width) {
                        if (modifiers & SDL_KMOD_CTRL)
                            change_map_size('E', -1);
                        else
                            change_map_size('E', 2);
                    }

                    if (modifiers & SDL_KMOD_SHIFT && tile_y == -1) {
                        if (modifiers & SDL_KMOD_CTRL)
                            change_map_size('N', -1);
                        else
                            change_map_size('N', 2);
                    }

                    if (modifiers & SDL_KMOD_SHIFT && tile_y == map_height) {
                        if (modifiers & SDL_KMOD_CTRL)
                            change_map_size('S', -1);
                        else
                            change_map_size('S', 2);
                    }
                } break;
            }
        }

        //Tiles updaten
        for (int y = 0; y < view_height; y++) {
            for (int x = 0; x < view_width; x++) {
                if (x + player.pos_x - view_width / 2 >= 0 && x + player.pos_x - view_width / 2 < map_width && 
                    y + player.pos_y - view_height / 2 >= 0 && y + player.pos_y - view_height / 2 < map_height) {
                    tiles_instances[x + y * view_width].tile_type = map_tiles[(x + player.pos_x - view_width / 2) + (y + player.pos_y - view_height / 2) * map_width];
                } else {
                    tiles_instances[x + y * view_width].tile_type = 0;
                }

                Uint32 type = tiles_instances[x + y * view_width].tile_type;

                float x0 = sma_item_x(tile_infos[type].atlas_item);
                float y0 = sma_item_y(tile_infos[type].atlas_item);
                float x1 = x0 + sma_item_width(tile_infos[type].atlas_item);
                float y1 = y0 + sma_item_height(tile_infos[type].atlas_item);

                tiles_instances[x + y * view_width].uv0uv1 = { x0 / tile_atlas_size, y0 / tile_atlas_size, x1 / tile_atlas_size, y1 / tile_atlas_size };
            }
        }

        if (!swapchain_texture) {
            SDL_CancelGPUCommandBuffer(command_buffer);
            ImGui::Render();
            ImDrawData *draw_data = ImGui::GetDrawData();
            continue;
        }

        per_frame.aspect_ratio = (float) window_width / (float) window_height;
        SDL_PushGPUVertexUniformData(command_buffer, 0, &per_frame, sizeof(per_frame));

        if (!update_buffer(tiles_instance_buffer, 0, sizeof(tiles_instances), tiles_instances)) {
            log_error("Failed to update buffer. Exiting.");
            return 1;
        }

        SDL_GPUColorTargetInfo color_target_info = {
            .texture     = swapchain_texture,
            .clear_color = { .r = 1.0f, .g = 0.0f, .b = 1.0f, .a = 1.0f },
            .load_op     = SDL_GPU_LOADOP_CLEAR,
            .store_op    = SDL_GPU_STOREOP_STORE,
        };

        SDL_GPURenderPass *render_pass = SDL_BeginGPURenderPass(command_buffer, &color_target_info, 1, NULL);
        if (!render_pass) {
            log_error("Failed to begin render pass. Exiting.");
            return 1;
        }

        { // Draw Map
            SDL_GPUBufferBinding index_buffer_binding = { .buffer = index_buffer, .offset = 0 };
            SDL_GPUBufferBinding vertex_buffers[] = {
                { .buffer = vertex_buffer,         .offset = 0 },
                { .buffer = tiles_instance_buffer, .offset = 0 },
            };
            SDL_GPUTextureSamplerBinding texture_bindings[] = {
                { .texture = tile_atlas_texture, .sampler = point_sampler },
            };

            SDL_BindGPUGraphicsPipeline(render_pass, basic_graphics_pipeline);
            SDL_BindGPUIndexBuffer(render_pass, &index_buffer_binding, SDL_GPU_INDEXELEMENTSIZE_16BIT);
            SDL_BindGPUVertexBuffers(render_pass, 0, vertex_buffers, SDL_arraysize(vertex_buffers));
            SDL_BindGPUFragmentSamplers(render_pass, 0, texture_bindings, SDL_arraysize(texture_bindings));
            SDL_DrawGPUIndexedPrimitives(render_pass, 6, view_width * view_height, 0, 0, 0);
        }

        { // Draw Player
            SDL_GPUBufferBinding vertex_buffers[] = {
                { .buffer = vertex_buffer,          .offset = 0 },
                { .buffer = player_instance_buffer, .offset = 0 },
            };
            SDL_GPUTextureSamplerBinding texture_bindings[] = {
                { .texture = player_texture, .sampler = point_sampler },
            };
            SDL_BindGPUGraphicsPipeline(render_pass, basic_graphics_pipeline);
            SDL_BindGPUVertexBuffers(render_pass, 0, vertex_buffers, SDL_arraysize(vertex_buffers));
            SDL_BindGPUFragmentSamplers(render_pass, 0, texture_bindings, SDL_arraysize(texture_bindings));
            SDL_DrawGPUIndexedPrimitives(render_pass, 6, 1, 0, 0, 0);
        }
        SDL_EndGPURenderPass(render_pass);

        ImGui::Render();
        ImDrawData *draw_data = ImGui::GetDrawData();
        Imgui_ImplSDLGPU3_PrepareDrawData(draw_data, command_buffer);

        SDL_GPUColorTargetInfo imgui_color_target_info = {
            .texture     = swapchain_texture,
            .load_op     = SDL_GPU_LOADOP_LOAD,
            .store_op    = SDL_GPU_STOREOP_STORE,
        };

        SDL_GPURenderPass *imgui_render_pass = SDL_BeginGPURenderPass(command_buffer, &imgui_color_target_info, 1, NULL);
        ImGui_ImplSDLGPU3_RenderDrawData(draw_data, command_buffer, imgui_render_pass);
        SDL_EndGPURenderPass(imgui_render_pass);
        
        if (!SDL_SubmitGPUCommandBuffer(command_buffer)) {
            log_error("Failed to submit gpu command buffer (%s). Exiting.", SDL_GetError());
            return 1;
        }
    }
    return 0;
}