const std = @import("std");

const zaudio = @import("zaudio");
const zglfw = @import("zglfw");
const zgpu = @import("zgpu");
const zgui = @import("zgui");
const ztracy = @import("ztracy");

const game = @import("game.zig");
const Log = @import("Log.zig");

pub const min_framerate = 30.0;
pub const min_frametime = 1.0 / min_framerate;
pub const min_window_height = 360;
pub const min_window_width = 640;
pub const temp_allocator_capacity = 16 * 1024 * 1024;
pub const window_title = "voxel-game";

pub var allocator: std.mem.Allocator = undefined;
pub var audio_engine: *zaudio.Engine = undefined;
pub var gctx: *zgpu.GraphicsContext = undefined;
pub var logs: std.ArrayListUnmanaged(Log) = undefined;
pub var temp_allocator: std.mem.Allocator = undefined;
pub var window: *zglfw.Window = undefined;

pub const std_options: std.Options = .{
    .logFn = logFn,
};

pub fn main() !void {
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    defer _ = gpa.deinit();

    var ta = ztracy.TracyAllocator.init(gpa.allocator());

    var fba = std.heap.FixedBufferAllocator.init(&struct {
        pub var buffer: [temp_allocator_capacity]u8 = undefined;
    }.buffer);

    allocator = ta.allocator();
    temp_allocator = fba.threadSafeAllocator();

    defer {
        for (logs.items) |log| {
            allocator.free(log.message);
        }
        logs.deinit(allocator);
    }

    // --- zaudio --------------------------------------------------------------

    const zone_init_zaudio = ztracy.ZoneN(@src(), "Init zaudio");

    zaudio.init(allocator);
    defer zaudio.deinit();

    audio_engine = try zaudio.Engine.create(null);
    defer audio_engine.destroy();

    zone_init_zaudio.End();

    // --- zglfw ---------------------------------------------------------------

    const zone_init_zglfw = ztracy.ZoneN(@src(), "Init zglfw");

    try zglfw.init();
    defer zglfw.terminate();

    const monitor = zglfw.getPrimaryMonitor() orelse return error.PrimaryMonitorNotFound;
    const video_mode = try monitor.getVideoMode();

    zglfw.windowHint(.client_api, .no_api);
    window = try zglfw.Window.create(video_mode.width, video_mode.height, window_title, monitor);
    window.setSizeLimits(
        min_window_width,
        min_window_height,
        -1,
        -1,
    );
    defer window.destroy();

    std.debug.assert(zglfw.setCharCallback(window, game.charCallback) == null);
    std.debug.assert(zglfw.setCursorPosCallback(window, game.cursorPosCallback) == null);
    std.debug.assert(zglfw.setKeyCallback(window, game.keyCallback) == null);
    std.debug.assert(zglfw.setMouseButtonCallback(window, game.mouseButtonCallback) == null);
    std.debug.assert(zglfw.setScrollCallback(window, game.scrollCallback) == null);

    zone_init_zglfw.End();

    // --- zgpu ----------------------------------------------------------------

    const zone_init_zgpu = ztracy.ZoneN(@src(), "Init zgpu");

    gctx = try zgpu.GraphicsContext.create(allocator, .{
        .window = window,
        .fn_getTime = @ptrCast(&zglfw.getTime),
        .fn_getFramebufferSize = @ptrCast(&zglfw.Window.getFramebufferSize),
        .fn_getWin32Window = @ptrCast(&zglfw.getWin32Window),
        .fn_getX11Display = @ptrCast(&zglfw.getX11Display),
        .fn_getX11Window = @ptrCast(&zglfw.getX11Window),
        .fn_getWaylandDisplay = @ptrCast(&zglfw.getWaylandDisplay),
        .fn_getWaylandSurface = @ptrCast(&zglfw.getWaylandWindow),
        .fn_getCocoaWindow = @ptrCast(&zglfw.getCocoaWindow),
    }, .{});
    defer gctx.destroy(allocator);

    zone_init_zgpu.End();

    // --- zgui ----------------------------------------------------------------

    const zone_init_zgui = ztracy.ZoneN(@src(), "Init zgui");

    zgui.init(allocator);
    defer zgui.deinit();

    zgui.backend.init(
        window,
        gctx.device,
        @intFromEnum(zgpu.GraphicsContext.swapchain_format),
        @intFromEnum(zgpu.wgpu.TextureFormat.undef),
    );
    defer zgui.backend.deinit();

    zgui.io.setIniFilename(null);

    zone_init_zgui.End();

    // --- game ----------------------------------------------------------------

    const zone_init_game = ztracy.ZoneN(@src(), "Init game");

    try game.init();
    defer game.deinit();

    zone_init_game.End();

    // --- main loop -----------------------------------------------------------

    const zone_main_loop = ztracy.ZoneN(@src(), "Main loop");

    var t2 = zglfw.getTime();

    while (!window.shouldClose()) {
        ztracy.FrameMark();

        fba.reset();

        const t1 = zglfw.getTime();
        const dt: f32 = @floatCast(@max(t2 - t1, min_frametime));
        t2 = t1;

        zglfw.pollEvents();
        zgui.backend.newFrame(
            gctx.swapchain_descriptor.width,
            gctx.swapchain_descriptor.height,
        );

        game.update(dt);

        const swapchain_texture_view = gctx.swapchain.getCurrentTextureView();
        defer swapchain_texture_view.release();

        const commands = commands: {
            const encoder = gctx.device.createCommandEncoder(null);
            defer encoder.release();

            {
                const pass = zgpu.beginRenderPassSimple(
                    encoder,
                    .load,
                    swapchain_texture_view,
                    null,
                    null,
                    null,
                );
                defer zgpu.endReleasePass(pass);
                zgui.backend.draw(pass);
            }

            break :commands encoder.finish(null);
        };
        defer commands.release();

        gctx.submit(&.{commands});
        _ = gctx.present();
    }

    zone_main_loop.End();
}

fn logFn(
    comptime level: std.log.Level,
    comptime _: @Type(.enum_literal),
    comptime fmt: []const u8,
    args: anytype,
) void {
    const message = std.fmt.allocPrint(allocator, fmt, args) catch return;
    logs.append(allocator, Log.init(level, message)) catch {
        allocator.free(message);
        return;
    };
}