const std = @import("std");

pub fn build(b: *std.Build) !void {
    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 exe = b.addExecutable(.{
        .name = "zx",
        // 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 = .{ .path = "src/main.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(exe);

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

    const run_main_tests = b.addRunArtifact(main_tests);

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

    // Setup comptime parsing for /lib files
    var markup_files = std.ArrayList([]const u8).init(b.allocator);
    var zig_files = std.ArrayList([]const u8).init(b.allocator);
    defer markup_files.deinit();
    defer zig_files.deinit();

    var options = b.addOptions();

    // Add all files names in the src folder to `files`
    var dir = try std.fs.cwd().openIterableDir("lib", .{});
    var lib_walker = try dir.walk(b.allocator);
    var walking = true;
    while (walking) blk: {
        var file = lib_walker.next() catch {
            walking = false;
            break :blk;
        };
        if (file == null) {
            walking = false;
            break :blk;
        }
        if (file.?.kind == .file) {
            const path = file.?.path;
            var split_iter = std.mem.splitBackwardsAny(u8, path, ".");
            var extension = split_iter.first();
            if (std.mem.eql(u8, extension, "zig")) {
                std.debug.print("Adding zig file {s}...\n", .{path});
                try zig_files.append(b.dupe(path));
            }
            else if (std.mem.eql(u8, extension, "html")) {
                std.debug.print("Adding markup file {s}...\n", .{path});
                try markup_files.append(b.dupe(path));
            } else {
                std.debug.print("Unrecognized file extension {s}\t{s}\n", .{extension, path});
            }
       }
        // std.debug.print("Got entry in `versions:` base: {s}, path: {s}, kind: {any}\n", .{ ver.?.basename, ver.?.path, ver.?.kind });
    }

    // Add the file names as an option to the exe, making it available
    // as a string array at comptime in main.zig
    options.addOption([]const []const u8, "zig_files", zig_files.items);
    options.addOption([]const []const u8, "markup_files", markup_files.items);
    exe.addOptions("options", options);
}