const std = @import("std");
const builtin = @import("builtin");
const dvui = @import("dvui");
const SDLBackend = @import("sdl-backend");

pub fn main() !void {
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    const allocator = gpa.allocator();

    var backend = try SDLBackend.initWindow(.{
        .allocator = allocator,
        .size = .{ .w = 800.0, .h = 600.0 },
        .title = "My DVUI App",
        .vsync = true,
    });
    defer backend.deinit();

    var win = try dvui.Window.init(@src(), allocator, backend.backend(), .{
        .theme = switch (backend.preferredColorScheme() orelse .light) {
            .light => dvui.Theme.builtin.adwaita_light,
            .dark => dvui.Theme.builtin.adwaita_dark,
        },
    });
    defer win.deinit();

    var interrupted = false;

    main_loop: while (true) {
        // beginWait coordinates with waitTime below to run frames only when needed
        const nstime = win.beginWait(interrupted);

        // marks the beginning of a frame for dvui, can call dvui functions after this
        try win.begin(nstime);

        // send all SDL events to dvui for processing
        try backend.addAllEvents(&win);

        // if dvui widgets might not cover the whole window, then need to clear
        // the previous frame's render
        _ = SDLBackend.c.SDL_SetRenderDrawColor(backend.renderer, 0, 0, 0, 255);
        _ = SDLBackend.c.SDL_RenderClear(backend.renderer);

        const keep_running = gui_frame();
        if (!keep_running) break :main_loop;

        // marks end of dvui frame, don't call dvui functions after this
        // - sends all dvui stuff to backend for rendering, must be called before renderPresent()
        const end_micros = try win.end(.{});

        // cursor management
        try backend.setCursor(win.cursorRequested());
        try backend.textInputRect(win.textInputRequested());

        // render frame to OS
        try backend.renderPresent();

        // waitTime and beginWait combine to achieve variable framerates
        const wait_event_micros = win.waitTime(end_micros);
        interrupted = try backend.waitEventTimeout(wait_event_micros);
    }
}

fn gui_frame() bool {
    return true;
}