const std = @import("std");
const mem = std.mem;
const path = std.fs.path;

const Build = std.Build;

const Scanner = @import("zig-wayland").Scanner;

// Although this function looks imperative, note that its job is to
// declaratively construct a build graph that will be executed by an external
// runner.
pub fn build(b: *std.Build) void {
    // Standard target options allows the person running `zig build` to choose
    // what target to build for. Here we do not override the defaults, which
    // means any target is allowed, and the default is native. Other options
    // for restricting supported target set are available.
    const target = b.standardTargetOptions(.{});

    // Standard optimization options allow the person running `zig build` to select
    // between Debug, ReleaseSafe, ReleaseFast, and ReleaseSmall. Here we do not
    // set a preferred release mode, allowing the user to decide how to optimize.
    const optimize = b.standardOptimizeOption(.{});

    const scanner = Scanner.create(b, .{});
    const wayland = b.createModule(.{ .root_source_file = scanner.result });

    scanner.addSystemProtocol("stable/xdg-shell/xdg-shell.xml");
    scanner.addSystemProtocol("unstable/idle-inhibit/idle-inhibit-unstable-v1.xml");

    const wlr_protocols_path = blk: {
        const pc_output = b.run(&.{ "pkg-config", "--variable=pkgdatadir", "wlr-protocols" });
        break :blk mem.trim(u8, pc_output, &std.ascii.whitespace);
    };

    scanner.addCustomProtocol(b.pathJoin(&.{ wlr_protocols_path, "unstable/wlr-layer-shell-unstable-v1.xml" }));
    scanner.addCustomProtocol(b.pathJoin(&.{ wlr_protocols_path, "unstable/wlr-foreign-toplevel-management-unstable-v1.xml" }));

    scanner.generate("wl_compositor", 1);
    scanner.generate("wl_shm", 1);
    scanner.generate("wl_output", 4);
    scanner.generate("xdg_wm_base", 6);
    scanner.generate("zwp_idle_inhibit_manager_v1", 1);
    scanner.generate("zwlr_foreign_toplevel_manager_v1", 3);
    scanner.generate("zwlr_layer_shell_v1", 4);

    // const lib = b.addStaticLibrary(.{
    //     .name = "vegetable-hamper",
    //     // In this case the main source file is merely a path, however, in more
    //     // complicated build scripts, this could be a generated file.
    //     .root_source_file = b.path("src/root.zig"),
    //     .target = target,
    //     .optimize = optimize,
    // });

    // // This declares intent for the library to be installed into the standard
    // // location when the user invokes the "install" step (the default step when
    // // running `zig build`).
    // b.installArtifact(lib);

    const exe = b.addExecutable(.{
        .name = "vegetable-hamper",
        .root_source_file = b.path("src/main.zig"),
        .target = target,
        .optimize = optimize,
    });

    // Add wayland module
    exe.root_module.addImport("wayland", wayland);
    exe.linkLibC();
    exe.linkSystemLibrary2("wayland-client", .{ .needed = true });
    exe.linkSystemLibrary2("wlroots", .{ .needed = true });

    scanner.addCSource(exe);

    // This declares intent for the executable to be installed into the
    // standard location when the user invokes the "install" step (the default
    // step when running `zig build`).
    b.installArtifact(exe);

    // This *creates* a Run step in the build graph, to be executed when another
    // step is evaluated that depends on it. The next line below will establish
    // such a dependency.
    const run_cmd = b.addRunArtifact(exe);

    // By making the run step depend on the install step, it will be run from the
    // installation directory rather than directly from within the cache directory.
    // This is not necessary, however, if the application depends on other installed
    // files, this ensures they will be present and in the expected location.
    run_cmd.step.dependOn(b.getInstallStep());

    // This allows the user to pass arguments to the application in the build
    // command itself, like this: `zig build run -- arg1 arg2 etc`
    if (b.args) |args| {
        run_cmd.addArgs(args);
    }

    // This creates a build step. It will be visible in the `zig build --help` menu,
    // and can be selected like this: `zig build run`
    // This will evaluate the `run` step rather than the default, which is "install".
    const run_step = b.step("run", "Run the app");
    run_step.dependOn(&run_cmd.step);

    // Creates a step for unit testing. This only builds the test executable
    // but does not run it.
    // const lib_unit_tests = b.addTest(.{
    //     .root_source_file = b.path("src/root.zig"),
    //     .target = target,
    //     .optimize = optimize,
    // });

    // const run_lib_unit_tests = b.addRunArtifact(lib_unit_tests);

    // const exe_unit_tests = b.addTest(.{
    //     .root_source_file = b.path("src/main.zig"),
    //     .target = target,
    //     .optimize = optimize,
    // });

    // const run_exe_unit_tests = b.addRunArtifact(exe_unit_tests);

    // Similar to creating the run step earlier, this exposes a `test` step to
    // the `zig build --help` menu, providing a way for the user to request
    // running the unit tests.
    // const test_step = b.step("test", "Run unit tests");
    // test_step.dependOn(&run_lib_unit_tests.step);
    // test_step.dependOn(&run_exe_unit_tests.step);
}