const std = @import("std");
const raylib = @import("libs/raylib/build.zig");
const fs = std.fs;

const app_name = "step-kill";

const raylibSrc = "libs/raylib/raylib/src/";
const raylibBindingSrc = "libs/raylib/";

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

    try switch (target.getOsTag()) {
        .wasi, .emscripten => buildWeb(b, target, optimize),
        else => buildDesktop(b, target, optimize)
    };
}

fn buildDesktop(b: *std.Build, target: std.zig.CrossTarget, optimize: std.builtin.Mode) !void {
    const exe = b.addExecutable(.{
        .name = app_name,
        .root_source_file = .{ .path = "src/platforms/desktop.zig" },
        .main_pkg_path = .{ .path = "src" },
        .target = target,
        .optimize = optimize,
    });

    const git_submodule_run = b.addSystemCommand(&.{"git", "submodule", "update", "--init", "--recursive"});
    exe.step.dependOn(&git_submodule_run.step);

    raylib.addTo(b, exe, target, optimize, .{});

    b.installArtifact(exe);

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

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

fn buildWeb(b: *std.Build, target: std.zig.CrossTarget, optimize: std.builtin.Mode) !void {
    const emscriptenSrc = "libs/raylib/emscripten/";
    const webCachedir = "zig-cache/web/";
    const webOutdir = "zig-out/web/";

    // TODO: Add depend step on 'git submodule update --recursive'
    // TODO: Add depend step on downloading emsdk

    std.log.info("building for emscripten\n", .{});
    if (b.sysroot == null) {
        std.log.err("\n\nUSAGE: Please build with 'zig build -Doptimize=ReleaseSmall -Dtarget=wasm32-wasi --sysroot \"$EMSDK/upstream/emscripten\"'\n\n", .{});
        return error.SysRootExpected;
    }
    const lib = b.addStaticLibrary(.{
        .name = app_name,
        .root_source_file = std.Build.LazyPath.relative("src/platforms/web.zig"),
        .main_pkg_path = .{ .path = "src" },
        .optimize = optimize,
        .target = target,
    });
    lib.addIncludePath(.{ .path = raylibSrc });

    const emcc_file = switch (b.host.target.os.tag) {
        .windows => "emcc.bat",
        else => "emcc",
    };
    const emar_file = switch (b.host.target.os.tag) {
        .windows => "emar.bat",
        else => "emar",
    };
    const emranlib_file = switch (b.host.target.os.tag) {
        .windows => "emranlib.bat",
        else => "emranlib",
    };

    const emcc_path = try fs.path.join(b.allocator, &.{ b.sysroot.?, emcc_file });
    defer b.allocator.free(emcc_path);
    const emranlib_path = try fs.path.join(b.allocator, &.{ b.sysroot.?, emranlib_file });
    defer b.allocator.free(emranlib_path);
    const emar_path = try fs.path.join(b.allocator, &.{ b.sysroot.?, emar_file });
    defer b.allocator.free(emar_path);
    const include_path = try fs.path.join(b.allocator, &.{ b.sysroot.?, "cache", "sysroot", "include" });
    defer b.allocator.free(include_path);

    fs.cwd().makePath(webCachedir) catch {};
    fs.cwd().makePath(webOutdir) catch {};

    const warnings = ""; //-Wall

    const rcoreO = b.addSystemCommand(&.{ emcc_path, "-Os", warnings, "-c", raylibSrc ++ "rcore.c", "-o", webCachedir ++ "rcore.o", "-Os", warnings, "-DPLATFORM_WEB", "-DGRAPHICS_API_OPENGL_ES2" });
    const rshapesO = b.addSystemCommand(&.{ emcc_path, "-Os", warnings, "-c", raylibSrc ++ "rshapes.c", "-o", webCachedir ++ "rshapes.o", "-Os", warnings, "-DPLATFORM_WEB", "-DGRAPHICS_API_OPENGL_ES2" });
    const rtexturesO = b.addSystemCommand(&.{ emcc_path, "-Os", warnings, "-c", raylibSrc ++ "rtextures.c", "-o", webCachedir ++ "rtextures.o", "-Os", warnings, "-DPLATFORM_WEB", "-DGRAPHICS_API_OPENGL_ES2" });
    const rtextO = b.addSystemCommand(&.{ emcc_path, "-Os", warnings, "-c", raylibSrc ++ "rtext.c", "-o", webCachedir ++ "rtext.o", "-Os", warnings, "-DPLATFORM_WEB", "-DGRAPHICS_API_OPENGL_ES2" });
    const rmodelsO = b.addSystemCommand(&.{ emcc_path, "-Os", warnings, "-c", raylibSrc ++ "rmodels.c", "-o", webCachedir ++ "rmodels.o", "-Os", warnings, "-DPLATFORM_WEB", "-DGRAPHICS_API_OPENGL_ES2" });
    const utilsO = b.addSystemCommand(&.{ emcc_path, "-Os", warnings, "-c", raylibSrc ++ "utils.c", "-o", webCachedir ++ "utils.o", "-Os", warnings, "-DPLATFORM_WEB" });
    const raudioO = b.addSystemCommand(&.{ emcc_path, "-Os", warnings, "-c", raylibSrc ++ "raudio.c", "-o", webCachedir ++ "raudio.o", "-Os", warnings, "-DPLATFORM_WEB" });

    const libraylibA = b.addSystemCommand(&.{
        emar_path,
        "rcs",
        webCachedir ++ "libraylib.a",
        webCachedir ++ "rcore.o",
        webCachedir ++ "rshapes.o",
        webCachedir ++ "rtextures.o",
        webCachedir ++ "rtext.o",
        webCachedir ++ "rmodels.o",
        webCachedir ++ "utils.o",
        webCachedir ++ "raudio.o",
    });
    const emranlib = b.addSystemCommand(&.{
        emranlib_path,
        webCachedir ++ "libraylib.a",
    });

    libraylibA.step.dependOn(&rcoreO.step);
    libraylibA.step.dependOn(&rshapesO.step);
    libraylibA.step.dependOn(&rtexturesO.step);
    libraylibA.step.dependOn(&rtextO.step);
    libraylibA.step.dependOn(&rmodelsO.step);
    libraylibA.step.dependOn(&utilsO.step);
    libraylibA.step.dependOn(&raudioO.step);
    emranlib.step.dependOn(&libraylibA.step);

    //only build raylib if not already there
    _ = fs.cwd().statFile(webCachedir ++ "libraylib.a") catch {
        lib.step.dependOn(&emranlib.step);
    };

    lib.defineCMacro("__EMSCRIPTEN__", null);
    lib.defineCMacro("PLATFORM_WEB", null);
    std.log.info("emscripten include path: {s}", .{include_path});
    lib.addIncludePath(.{ .path = include_path });
    lib.addIncludePath(.{ .path = emscriptenSrc });
    lib.addIncludePath(.{ .path = raylibBindingSrc });
    lib.addIncludePath(.{ .path = raylibSrc });
    lib.addIncludePath(.{ .path = raylibSrc ++ "extras/" });
    lib.addAnonymousModule("raylib", .{ .source_file = .{ .path = raylibBindingSrc ++ "raylib.zig" } });
    // lib.root_module.addAnonymousImport("raylib", .{ .root_source_file = .{ .path = raylibBindingSrc ++ "raylib.zig" } });

    const libraryOutputFolder = "zig-out/lib/";
    // this installs the lib (libraylib-zig-examples.a) to the `libraryOutputFolder` folder
    b.installArtifact(lib);

    const shell = switch (optimize) {
        .Debug => emscriptenSrc ++ "shell.html",
        else => emscriptenSrc ++ "minshell.html",
    };

    const emcc = b.addSystemCommand(&.{
        emcc_path,
        "-o",
        webOutdir ++ "game.html",

        emscriptenSrc ++ "entry.c",
        raylibBindingSrc ++ "marshal.c",

        libraryOutputFolder ++ "lib" ++ app_name ++ ".a",
        "-I.",
        "-I" ++ raylibSrc,
        "-I" ++ emscriptenSrc,
        "-I" ++ raylibBindingSrc,
        "-L.",
        "-L" ++ webCachedir,
        "-L" ++ libraryOutputFolder,
        "-lraylib",
        "-l" ++ app_name,
        "--shell-file",
        shell,
        "-DPLATFORM_WEB",
        "-sUSE_GLFW=3",
        "-sWASM=1",
        "-sALLOW_MEMORY_GROWTH=1",
        "-sWASM_MEM_MAX=512MB", //going higher than that seems not to work on iOS browsers ¯\_(ツ)_/¯
        "-sTOTAL_MEMORY=512MB",
        "-sABORTING_MALLOC=0",
        "-sASYNCIFY",
        "-sFORCE_FILESYSTEM=1",
        "-sASSERTIONS=1",
        // "--memory-init-file",
        // "0",
        // "--preload-file",
        // "assets",
        // "--source-map-base",
        "-O1",
        "-Os",
        // "-sLLD_REPORT_UNDEFINED",
        "-sERROR_ON_UNDEFINED_SYMBOLS=0",

        // optimizations
        "-O1",
        "-Os",

        // "-sUSE_PTHREADS=1",
        // "--profiling",
        // "-sTOTAL_STACK=128MB",
        // "-sMALLOC='emmalloc'",
        // "--no-entry",
        "-sEXPORTED_FUNCTIONS=['_malloc','_free','_main', '_emsc_main','_emsc_set_window_size']",
        "-sEXPORTED_RUNTIME_METHODS=ccall,cwrap",
    });

    emcc.step.dependOn(&lib.step);

    b.getInstallStep().dependOn(&emcc.step);
    //-------------------------------------------------------------------------------------

    std.log.info("\n\nOutput files will be in {s}\n---\ncd {s}\npython -m http.server\n---\n\nbuilding...", .{ webOutdir, webOutdir });
}