const std = @import("std");
const zcc = @import("compile_commands");

pub fn build(b: *std.Build) !void {
    const target = b.standardTargetOptions(.{ });
    const optimize = b.standardOptimizeOption(.{});

    const tracy_enabled = b.option(bool, "tracy", "Enable tracy profiling") orelse (optimize == .Debug);
    const imgui_enabled = b.option(bool, "imgui", "Enable ImGui integration") orelse (optimize == .Debug);

    var targets: std.ArrayList(*std.Build.Step.Compile) = .empty;

    const mod = b.createModule(.{
        .target = target,
        .optimize = optimize,
        .link_libc = true,
    });
    mod.addIncludePath(b.path("./src/"));

    var cflags: std.ArrayList([]const u8) = .empty;

    const raylib_dep = b.dependency("raylib", .{
        .target = target,
        .optimize = optimize
    });
    mod.linkLibrary(raylib_dep.artifact("raylib"));

    const tracy_dep = b.dependency("tracy", .{
        .tracy_enable = tracy_enabled,
    });
    mod.linkLibrary(tracy_dep.artifact("tracy"));

    const incbin_dep = b.dependency("incbin", .{});
    mod.addIncludePath(incbin_dep.path("."));

    if (imgui_enabled) {
        if (try buildImGui(b, .{
            .target = target,
            .optimize = optimize,
            .raylib = raylib_dep.artifact("raylib")
        })) |imgui| {
            mod.linkLibrary(imgui);
            try targets.append(b.allocator, imgui);
        }

        try cflags.append(b.allocator, "-DIMGUI_ENABLED");
    }

    {
        var src_dir = try std.fs.cwd().openDir("src", .{ .iterate = true });
        defer src_dir.close();

        var iter = src_dir.iterate();
        while (try iter.next()) |entry| {
            if (entry.kind == .file and std.mem.endsWith(u8, entry.name, ".c")) {
                mod.addCSourceFile(.{
                    .file = b.path(b.pathJoin(&.{ "src", entry.name })),
                    .flags = cflags.items
                });
            }
        }
    }

    const exe = b.addExecutable(.{
        .name = "gaem",
        .root_module = mod
    });
    try targets.append(b.allocator, exe);

    if (target.result.os.tag == .windows) {
        const show_console = b.option(bool, "console", "Show windows console") orelse (optimize == .Debug);
        exe.subsystem = if (show_console) .Console else .Windows;
    }

    b.installArtifact(exe);

    {
        const run_cmd = b.addRunArtifact(exe);
        run_cmd.step.dependOn(b.getInstallStep());

        if (b.args) |args| {
            run_cmd.addArgs(args);
        }

        const run_step = b.step("run", "Run the program");
        run_step.dependOn(&run_cmd.step);
    }

    _ = zcc.createStep(b, "cdb", try targets.toOwnedSlice(b.allocator));
}

const ImGuiOptions = struct {
    target: std.Build.ResolvedTarget,
    optimize: std.builtin.OptimizeMode,
    raylib: *std.Build.Step.Compile
};

fn buildImGui(b: *std.Build, opts: ImGuiOptions) !?*std.Build.Step.Compile {
    const imgui = b.lazyDependency("imgui", .{}) orelse return null;
    const cimgui = b.lazyDependency("cimgui", .{}) orelse return null;
    const rlimgui = b.lazyDependency("rlimgui", .{}) orelse return null;

    const cpp_flags = .{
        "-fno-exceptions",
        "-fno-rtti",
        "-std=c++11",
        "-DNO_FONT_AWESOME"
    };

    const imgui_lib = b.addLibrary(.{
        .name = "imgui",
        .root_module = b.createModule(.{
            .target = opts.target,
            .optimize = opts.optimize,
            .link_libcpp = true,
        })
    });

    imgui_lib.root_module.addCSourceFiles(.{
        .root = imgui.path("."),
        .files = &.{
            "imgui.cpp",
            "imgui_demo.cpp",
            "imgui_draw.cpp",
            "imgui_tables.cpp",
            "imgui_widgets.cpp",
        },
        .flags = &cpp_flags
    });
    imgui_lib.root_module.addIncludePath(imgui.path("."));

    // Needed for cimgui
    imgui_lib.installHeadersDirectory(imgui.path("."), "imgui", .{});
    // Needed for rlimgui
    imgui_lib.installHeadersDirectory(imgui.path("."), ".", .{});

    const lib = b.addLibrary(.{
        .name = "imgui_raylib_cimgui",
        .root_module = b.createModule(.{
            .target = opts.target,
            .optimize = opts.optimize,
            .link_libcpp = true,
        })
    });
    lib.root_module.linkLibrary(imgui_lib);

    lib.root_module.addCSourceFile(.{
        .file = cimgui.path("cimgui.cpp"),
        .flags = &cpp_flags
    });
    lib.root_module.addIncludePath(cimgui.path("."));

    lib.root_module.addCSourceFile(.{
        .file = rlimgui.path("rlImGui.cpp"),
        .flags = &cpp_flags,
    });
    lib.root_module.addIncludePath(rlimgui.path("."));
    lib.root_module.linkLibrary(opts.raylib);

    lib.installHeader(rlimgui.path("rlImGui.h"), "rlImGui.h");
    lib.installHeader(cimgui.path("cimgui.h"), "cimgui.h");

    return lib;
}