// zig fmt: off
const std = @import("std");
const Api = @import("artifacts-api");
const Artificer = @import("artificer");
const UI = @import("./ui.zig");
const UIStack = @import("./ui_stack.zig");
const RectUtils = @import("./rect_utils.zig");
const rl = @import("raylib");
const srcery = @import("./srcery.zig");

const assert = std.debug.assert;

const App = @This();

const MapTexture = struct {
    name: Api.Map.Skin,
    texture: rl.Texture2D,
};

ui: UI,
artificer: *Artificer,
map_textures: std.ArrayList(MapTexture),
map_texture_indexes: std.ArrayList(usize),
map_position_min: Api.Position,
map_position_max: Api.Position,
camera: rl.Camera2D,

blur_texture_original: ?rl.RenderTexture = null,
blur_texture_horizontal: ?rl.RenderTexture = null,
blur_texture_both: ?rl.RenderTexture = null,
blur_shader: rl.Shader,

pub fn init(allocator: std.mem.Allocator, artificer: *Artificer) !App {
    const store = artificer.server.store;

    var map_textures = std.ArrayList(MapTexture).init(allocator);
    errdefer map_textures.deinit();
    errdefer {
        for (map_textures.items) |map_texture| {
            map_texture.texture.unload();
        }
    }

    var map_texture_indexes = std.ArrayList(usize).init(allocator);
    errdefer map_texture_indexes.deinit();

    // Load all map textures from api store
    {
        const map_image_ids = store.images.category_mapping.get(.map).items;
        try map_textures.ensureTotalCapacity(map_image_ids.len);

        for (map_image_ids) |image_id| {
            const image = store.images.get(image_id).?;
            const texture = rl.loadTextureFromImage(rl.Image{
                .width = @intCast(image.width),
                .height = @intCast(image.height),
                .data = store.images.getRGBA(image_id).?.ptr,
                .mipmaps = 1,
                .format = rl.PixelFormat.pixelformat_uncompressed_r8g8b8a8
            });
            if (!rl.isTextureReady(texture)) {
                return error.LoadMapTextureFromImage;
            }

            map_textures.appendAssumeCapacity(MapTexture{
                .name = try Api.Map.Skin.fromSlice(image.code.slice()),
                .texture = texture
            });
        }
    }

    var map_position_max = Api.Position.zero();
    var map_position_min = Api.Position.zero();
    for (store.maps.items) |map| {
        map_position_min.x = @min(map_position_min.x, map.position.x);
        map_position_min.y = @min(map_position_min.y, map.position.y);

        map_position_max.x = @max(map_position_max.x, map.position.x);
        map_position_max.y = @max(map_position_max.y, map.position.y);
    }
    const map_size = map_position_max.subtract(map_position_min);

    try map_texture_indexes.ensureTotalCapacity(@intCast(map_size.x * map_size.y));

    for (0..@intCast(map_size.y)) |oy| {
        for (0..@intCast(map_size.x)) |ox| {
            const x = map_position_min.x + @as(i64, @intCast(ox));
            const y = map_position_min.y + @as(i64, @intCast(oy));
            const map = store.getMap(.{ .x = x, .y = y }).?;

            var found_texture = false;
            const map_skin = map.skin.slice();
            for (0.., map_textures.items) |i, map_texture| {
                if (std.mem.eql(u8, map_skin, map_texture.name.slice())) {
                    map_texture_indexes.appendAssumeCapacity(i);
                    found_texture = true;
                    break;
                }
            }

            if (!found_texture) {
                return error.MapImageNotFound;
            }
        }
    }

    const blur_shader = rl.loadShaderFromMemory(
        @embedFile("./base.vsh"),
        @embedFile("./blur.fsh"),
    );
    if (!rl.isShaderReady(blur_shader)) {
        return error.LoadShaderFromMemory;
    }

    return App{
        .artificer = artificer,
        .ui = UI.init(),
        .map_textures = map_textures,
        .map_texture_indexes = map_texture_indexes,
        .map_position_max = map_position_max,
        .map_position_min = map_position_min,
        .blur_shader = blur_shader,
        .camera = rl.Camera2D{
            .offset = rl.Vector2.zero(),
            .target = rl.Vector2.zero(),
            .rotation = 0,
            .zoom = 1,
        }
    };
}

pub fn deinit(self: *App) void {
    for (self.map_textures.items) |map_texture| {
        map_texture.texture.unload();
    }

    self.ui.deinit();
    self.map_textures.deinit();
    self.map_texture_indexes.deinit();

    if (self.blur_texture_horizontal) |render_texture| {
        render_texture.unload();
    }
    if (self.blur_texture_both) |render_texture| {
        render_texture.unload();
    }
    if (self.blur_texture_original) |render_texture| {
        render_texture.unload();
    }
}

fn cameraControls(camera: *rl.Camera2D) void {
    if (rl.isMouseButtonDown(.mouse_button_left)) {
        const mouse_delta = rl.getMouseDelta();
        camera.target.x -= mouse_delta.x / camera.zoom;
        camera.target.y -= mouse_delta.y / camera.zoom;
    }

    const zoom_speed = 0.2;
    const min_zoom = 0.1;
    const max_zoom = 2;
    const zoom_delta = rl.getMouseWheelMove();
    if (zoom_delta != 0) {
        const mouse_screen = rl.getMousePosition();

        // Get the world point that is under the mouse
        const mouse_world = rl.getScreenToWorld2D(mouse_screen, camera.*);

        // Set the offset to where the mouse is
        camera.offset = mouse_screen;

        // Set the target to match, so that the camera maps the world space point 
        // under the cursor to the screen space point under the cursor at any zoom
        camera.target = mouse_world;

        // Zoom increment
        camera.zoom *= (1 + zoom_delta * zoom_speed);
        camera.zoom = std.math.clamp(camera.zoom, min_zoom, max_zoom);
    }
}

// fn drawCharacterInfo(ui: *UI, rect: rl.Rectangle, artificer: *Artificer, brain: *Artificer.Brain) !void {
//     var buffer: [256]u8 = undefined;
//
//     const name_height = 20;
//     UI.drawTextCentered(ui.font, brain.name, .{ .x = RectUtils.center(rect).x, .y = rect.y + name_height / 2 }, 20, 2, srcery.bright_white);
//
//     var label_stack = UIStack.init(RectUtils.shrinkTop(rect, name_height + 4), .top_to_bottom);
//     label_stack.gap = 4;
//
//     const now = std.time.milliTimestamp();
//     const cooldown = brain.cooldown(&artificer.server);
//     const seconds_left: f32 = @as(f32, @floatFromInt(@max(cooldown - now, 0))) / std.time.ms_per_s;
//     const cooldown_label = try std.fmt.bufPrint(&buffer, "Cooldown: {d:.3}", .{seconds_left});
//     UI.drawTextEx(ui.font, cooldown_label, RectUtils.topLeft(label_stack.next(16)), 16, 2, srcery.bright_white);
//
//     var task_label: []u8 = undefined;
//     if (brain.task) |task| {
//         task_label = try std.fmt.bufPrint(&buffer, "Task: {s}", .{@tagName(task)});
//     } else {
//         task_label = try std.fmt.bufPrint(&buffer, "Task: -", .{});
//     }
//     UI.drawTextEx(ui.font, task_label, RectUtils.topLeft(label_stack.next(16)), 16, 2, srcery.bright_white);
//
//     const actions_label = try std.fmt.bufPrint(&buffer, "Actions: {}", .{brain.action_queue.items.len});
//     UI.drawTextEx(ui.font, actions_label, RectUtils.topLeft(label_stack.next(16)), 16, 2, srcery.bright_white);
// }

fn createOrGetRenderTexture(maybe_render_texture: *?rl.RenderTexture) !rl.RenderTexture {
    const screen_width = rl.getScreenWidth();
    const screen_height = rl.getScreenHeight();

    if (maybe_render_texture.*) |render_texture| {
        if (render_texture.texture.width != screen_width or render_texture.texture.height != screen_height) {
            render_texture.unload();
            maybe_render_texture.* = null;
        }
    }

    if (maybe_render_texture.* == null) {
        const render_texture = rl.loadRenderTexture(screen_width, screen_height);
        if (!rl.isRenderTextureReady(render_texture)) {
            return error.LoadRenderTexture;
        }

        maybe_render_texture.* = render_texture;
    }

    return maybe_render_texture.*.?;
}

fn drawRectangleRoundedUV(rect: rl.Rectangle, roundness: f32, color: rl.Color) void {
    if (roundness == 0) {
        rl.drawRectangleRec(rect, color);
    }
}

fn drawBlurredWorld(self: *App, rect: rl.Rectangle, roundness: f32, color: rl.Color) !void {
    const blur_both = try createOrGetRenderTexture(&self.blur_texture_both);

    const previous_texture = rl.getShapesTexture();
    const previous_rect = rl.getShapesTextureRectangle();
    defer rl.setShapesTexture(previous_texture, previous_rect);

    const texture_height: f32 = @floatFromInt(blur_both.texture.height);
    const shape_rect = rl.Rectangle{
        .x = rect.x,
        .y = texture_height - rect.y,
        .width = rect.width,
        .height = -rect.height,
    };
    rl.setShapesTexture(blur_both.texture, shape_rect);
    drawRectangleRoundedUV(rect, roundness, 0, color);
}

pub fn drawWorld(self: *App) !void {
    const screen_width = rl.getScreenWidth();
    const screen_height = rl.getScreenHeight();
    const screen_size = rl.Vector2.init(@floatFromInt(screen_width), @floatFromInt(screen_height));

    const blur_original = try createOrGetRenderTexture(&self.blur_texture_original);
    const blur_horizontal = try createOrGetRenderTexture(&self.blur_texture_horizontal);
    const blur_both = try createOrGetRenderTexture(&self.blur_texture_both);

    // 1 pass. Draw the all of the sprites  
    {
        blur_original.begin();
        defer blur_original.end();

        rl.clearBackground(rl.Color.black.alpha(0));

        self.camera.begin();
        defer self.camera.end();

        rl.drawCircleV(rl.Vector2.zero(), 5, rl.Color.red);

        const map_size = self.map_position_max.subtract(self.map_position_min);
        for (0..@intCast(map_size.y)) |oy| {
            for (0..@intCast(map_size.x)) |ox| {
                const map_index = @as(usize, @intCast(map_size.x)) * oy + ox;
                const x = self.map_position_min.x + @as(i64, @intCast(ox));
                const y = self.map_position_min.y + @as(i64, @intCast(oy));
                const texture_index = self.map_texture_indexes.items[map_index];
                const texture = self.map_textures.items[texture_index].texture;

                const tile_size = rl.Vector2.init(224, 224);
                const position = rl.Vector2.init(@floatFromInt(x), @floatFromInt(y)).multiply(tile_size);
                rl.drawTextureV(texture, position, rl.Color.white);
            }
        }
    }

    // 2 pass. Apply horizontal blur
    const kernel_radius: i32 = 16;
    var kernel_coeffs: [kernel_radius * 2 + 1]f32 = undefined;
    {
        const sigma = 10;

        for (0..kernel_coeffs.len) |i| {
            const i_i32: i32 = @intCast(i);
            const io: f32 = @floatFromInt(i_i32 - kernel_radius);
            kernel_coeffs[i] = @exp(-(io * io) / (sigma * sigma));
            // kernel_coeffs[i] /= @floatFromInt(kernel_coeffs.len);
        }

        var kernel_sum: f32 = 0;
        for (kernel_coeffs) |coeff| {
            kernel_sum += coeff;
        }

        for (&kernel_coeffs) |*coeff| {
            coeff.* /= kernel_sum;
        }
    }

    {
        const texture_size_loc = rl.getShaderLocation(self.blur_shader, "textureSize");
        assert(texture_size_loc != -1);

        rl.setShaderValue(self.blur_shader, texture_size_loc, &screen_size, .shader_uniform_vec2);
    }

    {
        const kernel_radius_loc = rl.getShaderLocation(self.blur_shader, "kernelRadius");
        assert(kernel_radius_loc != -1);

        rl.setShaderValue(self.blur_shader, kernel_radius_loc, &kernel_radius, .shader_uniform_int);
    }

    {
        const coeffs_loc = rl.getShaderLocation(self.blur_shader, "coeffs");
        assert(coeffs_loc != -1);

        rl.setShaderValueV(self.blur_shader, coeffs_loc, &kernel_coeffs, .shader_uniform_float, kernel_coeffs.len);
    }

    {
        const kernel_direction_loc = rl.getShaderLocation(self.blur_shader, "kernelDirection");
        assert(kernel_direction_loc != -1);

        const kernel_direction = rl.Vector2.init(1, 0);
        rl.setShaderValue(self.blur_shader, kernel_direction_loc, &kernel_direction, .shader_uniform_vec2);
    }

    {
        blur_horizontal.begin();
        defer blur_horizontal.end();

        rl.clearBackground(rl.Color.black.alpha(0));

        self.blur_shader.activate();
        defer self.blur_shader.deactivate();

        rl.drawTextureRec(
            blur_original.texture,
            .{
                .x = 0,
                .y = 0,
                .width = screen_size.x,
                .height = -screen_size.y,
            },
            rl.Vector2.zero(),
            rl.Color.white
        );
    }

    // 3 pass. Apply vertical blur
    {
        const kernel_direction_loc = rl.getShaderLocation(self.blur_shader, "kernelDirection");
        assert(kernel_direction_loc != -1);

        const kernel_direction = rl.Vector2.init(0, 1);
        rl.setShaderValue(self.blur_shader, kernel_direction_loc, &kernel_direction, .shader_uniform_vec2);
    }

    {
        blur_both.begin();
        defer blur_both.end();

        self.blur_shader.activate();
        defer self.blur_shader.deactivate();

        rl.drawTextureRec(
            blur_horizontal.texture,
            .{
                .x = 0,
                .y = 0,
                .width = screen_size.x,
                .height = -screen_size.y,
            },
            rl.Vector2.zero(),
            rl.Color.white
        );
    }

    // Last thing, draw world without blur
    rl.drawTextureRec(
        blur_original.texture,
        .{
            .x = 0,
            .y = 0,
            .width = @floatFromInt(blur_original.texture.width),
            .height = @floatFromInt(-blur_original.texture.height),
        },
        rl.Vector2.zero(),
        rl.Color.white
    );
}

pub fn tick(self: *App) !void {
    try self.artificer.tick();

    const screen_width = rl.getScreenWidth();
    const screen_height = rl.getScreenHeight();
    const screen_size = rl.Vector2.init(@floatFromInt(screen_width), @floatFromInt(screen_height));

    cameraControls(&self.camera);

    rl.beginDrawing();
    defer rl.endDrawing();

    rl.clearBackground(srcery.black);

    try self.drawWorld();

    try self.drawBlurredWorld(
        .{ .x = 20, .y = 20, .width = 200, .height = 200 },
        0.5,
        rl.Color.gray
    );

    rl.drawFPS(
        @as(i32, @intFromFloat(screen_size.x)) - 100,
        @as(i32, @intFromFloat(screen_size.y)) - 24
    );

    // var info_stack = UIStack.init(rl.Rectangle.init(0, 0, screen_size.x, screen_size.y), .left_to_right);
    // for (artificer.characters.items) |*brain| {
    //     const info_width = screen_size.x / @as(f32, @floatFromInt(artificer.characters.items.len));
    //     try drawCharacterInfo(&ui, info_stack.next(info_width), &artificer, brain);
    // }
}