const std = @import("std");
const fmt = std.fmt;
const fs = std.fs;
const heap = std.heap;
const mem = std.mem;
const LibExeObjStep = std.build.LibExeObjStep;
const Target = std.Target;

pub fn build(b: *std.build.Builder) !void {
    const src_path = "src/libsodium";
    const src_dir = try fs.Dir.openIterableDir(fs.cwd(), src_path, .{ .no_follow = true });

    const target = b.standardTargetOptions(.{});
    const optimize = b.standardOptimizeOption(.{});

    const enable_benchmarks = b.option(bool, "enable_benchmarks", "Whether tests should be benchmarks.") orelse false;
    const benchmarks_iterations = b.option(u32, "iterations", "Number of iterations for benchmarks.") orelse 200;

    const static = b.addStaticLibrary(.{
        .name = "sodium",
        .target = target,
        .optimize = optimize,
    });

    const libs = [_]*LibExeObjStep{static};

    const prebuilt_version_file_path = "builds/msvc/version.h";
    const version_file_path = "include/sodium/version.h";

    if (src_dir.dir.access(version_file_path, .{ .mode = .read_only })) {} else |_| {
        try fs.cwd().copyFile(prebuilt_version_file_path, src_dir.dir, version_file_path, .{});
    }

    for (libs) |lib| {
        b.installArtifact(lib);
        if (optimize != .Debug) {
            lib.strip = true;
        }
        lib.linkLibC();

        lib.addIncludePath(.{ .path = "src/libsodium/include/sodium" });
        lib.defineCMacro("_GNU_SOURCE", "1");
        lib.defineCMacro("CONFIGURED", "1");
        lib.defineCMacro("DEV_MODE", "1");
        lib.defineCMacro("HAVE_ATOMIC_OPS", "1");
        lib.defineCMacro("HAVE_C11_MEMORY_FENCES", "1");
        lib.defineCMacro("HAVE_CET_H", "1");
        lib.defineCMacro("HAVE_GCC_MEMORY_FENCES", "1");
        lib.defineCMacro("HAVE_INLINE_ASM", "1");
        lib.defineCMacro("HAVE_INTTYPES_H", "1");
        lib.defineCMacro("HAVE_STDINT_H", "1");
        lib.defineCMacro("HAVE_TI_MODE", "1");

        if (target.cpu_arch) |arch| {
            switch (arch.endian()) {
                .Big => lib.defineCMacro("NATIVE_BIG_ENDIAN", "1"),
                .Little => lib.defineCMacro("NATIVE_LITTLE_ENDIAN", "1"),
            }
        }

        switch (target.getOsTag()) {
            .linux => {
                lib.defineCMacro("ASM_HIDE_SYMBOL", ".hidden");
                lib.defineCMacro("TLS", "_Thread_local");

                lib.defineCMacro("HAVE_CATCHABLE_ABRT", "1");
                lib.defineCMacro("HAVE_CATCHABLE_SEGV", "1");
                lib.defineCMacro("HAVE_CLOCK_GETTIME", "1");
                lib.defineCMacro("HAVE_GETPID", "1");
                lib.defineCMacro("HAVE_INLINE_ASM", "1");
                lib.defineCMacro("HAVE_MADVISE", "1");
                lib.defineCMacro("HAVE_MLOCK", "1");
                lib.defineCMacro("HAVE_MMAP", "1");
                lib.defineCMacro("HAVE_MPROTECT", "1");
                lib.defineCMacro("HAVE_NANOSLEEP", "1");
                lib.defineCMacro("HAVE_POSIX_MEMALIGN", "1");
                lib.defineCMacro("HAVE_PTHREAD_PRIO_INHERIT", "1");
                lib.defineCMacro("HAVE_PTHREAD", "1");
                lib.defineCMacro("HAVE_RAISE", "1");
                lib.defineCMacro("HAVE_SYSCONF", "1");
                lib.defineCMacro("HAVE_SYS_AUXV_H", "1");
                lib.defineCMacro("HAVE_SYS_MMAN_H", "1");
                lib.defineCMacro("HAVE_SYS_PARAM_H", "1");
                lib.defineCMacro("HAVE_SYS_RANDOM_H", "1");
                lib.defineCMacro("HAVE_WEAK_SYMBOLS", "1");
            },
            .windows => {
                lib.defineCMacro("HAVE_RAISE", "1");
                lib.defineCMacro("HAVE_SYS_PARAM_H", "1");
                if (lib == static) {
                    lib.defineCMacro("SODIUM_STATIC", "1");
                }
            },
            .macos => {
                lib.defineCMacro("ASM_HIDE_SYMBOL", ".private_extern");
                lib.defineCMacro("TLS", "_Thread_local");

                lib.defineCMacro("HAVE_ARC4RANDOM", "1");
                lib.defineCMacro("HAVE_ARC4RANDOM_BUF", "1");
                lib.defineCMacro("HAVE_CATCHABLE_ABRT", "1");
                lib.defineCMacro("HAVE_CATCHABLE_SEGV", "1");
                lib.defineCMacro("HAVE_CLOCK_GETTIME", "1");
                lib.defineCMacro("HAVE_GETENTROPY", "1");
                lib.defineCMacro("HAVE_GETPID", "1");
                lib.defineCMacro("HAVE_MADVISE", "1");
                lib.defineCMacro("HAVE_MEMSET_S", "1");
                lib.defineCMacro("HAVE_MLOCK", "1");
                lib.defineCMacro("HAVE_MMAP", "1");
                lib.defineCMacro("HAVE_MPROTECT", "1");
                lib.defineCMacro("HAVE_NANOSLEEP", "1");
                lib.defineCMacro("HAVE_POSIX_MEMALIGN", "1");
                lib.defineCMacro("HAVE_PTHREAD", "1");
                lib.defineCMacro("HAVE_PTHREAD_PRIO_INHERIT", "1");
                lib.defineCMacro("HAVE_RAISE", "1");
                lib.defineCMacro("HAVE_SYSCONF", "1");
                lib.defineCMacro("HAVE_SYS_MMAN_H", "1");
                lib.defineCMacro("HAVE_SYS_PARAM_H", "1");
                lib.defineCMacro("HAVE_SYS_RANDOM_H", "1");
                lib.defineCMacro("HAVE_WEAK_SYMBOLS", "1");
            },
            .wasi => {
                lib.defineCMacro("HAVE_ARC4RANDOM", "1");
                lib.defineCMacro("HAVE_ARC4RANDOM_BUF", "1");
                lib.defineCMacro("HAVE_CLOCK_GETTIME", "1");
                lib.defineCMacro("HAVE_GETENTROPY", "1");
                lib.defineCMacro("HAVE_NANOSLEEP", "1");
                lib.defineCMacro("HAVE_POSIX_MEMALIGN", "1");
                lib.defineCMacro("HAVE_SYS_AUXV_H", "1");
                lib.defineCMacro("HAVE_SYS_PARAM_H", "1");
                lib.defineCMacro("HAVE_SYS_RANDOM_H", "1");
            },
            else => {},
        }

        switch (target.getCpuArch()) {
            .x86_64 => {
                lib.defineCMacro("HAVE_AMD64_ASM", "1");
                lib.defineCMacro("HAVE_AVX_ASM", "1");
                lib.defineCMacro("HAVE_CPUID", "1");
                lib.defineCMacro("HAVE_MMINTRIN_H", "1");
                lib.defineCMacro("HAVE_EMMINTRIN_H", "1");
                lib.defineCMacro("HAVE_PMMINTRIN_H", "1");
                lib.defineCMacro("HAVE_SMMINTRIN_H", "1");
                lib.defineCMacro("HAVE_TMMINTRIN_H", "1");
                lib.defineCMacro("HAVE_WMMINTRIN_H", "1");
            },
            .aarch64, .aarch64_be => {
                const cpu_features = target.getCpuFeatures();
                const has_neon = cpu_features.isEnabled(@intFromEnum(Target.aarch64.Feature.neon));
                const has_crypto = cpu_features.isEnabled(@intFromEnum(Target.aarch64.Feature.crypto));
                if (has_neon and has_crypto) {
                    lib.defineCMacro("HAVE_ARMCRYPTO", "1");
                }
            },
            .wasm32, .wasm64 => {
                lib.defineCMacro("__wasm__", "1");
            },
            else => {},
        }

        switch (target.getOsTag()) {
            .wasi => {
                lib.defineCMacro("__wasi__", "1");
            },
            else => {},
        }

        switch (target.getCpuArch()) {
            .x86_64 => {
                lib.target.cpu_features_add.addFeature(@intFromEnum(Target.x86.Feature.sse4_1));
                lib.target.cpu_features_add.addFeature(@intFromEnum(Target.x86.Feature.aes));
                lib.target.cpu_features_add.addFeature(@intFromEnum(Target.x86.Feature.pclmul));
            },
            else => {},
        }

        var allocator = heap.page_allocator;
        var walker = try src_dir.walk(allocator);
        while (try walker.next()) |entry| {
            const name = entry.basename;
            if (mem.endsWith(u8, name, ".c")) {
                const full_path = try fmt.allocPrint(allocator, "{s}/{s}", .{ src_path, entry.path });
                lib.addCSourceFiles(&.{full_path}, &.{
                    "-fvisibility=hidden",
                    "-fno-strict-aliasing",
                    "-fno-strict-overflow",
                    "-fwrapv",
                    "-flax-vector-conversions",
                });
            } else if (mem.endsWith(u8, name, ".S")) {
                const full_path = try fmt.allocPrint(allocator, "{s}/{s}", .{ src_path, entry.path });
                lib.addAssemblyFile(.{ .path = full_path });
            }
        }
    }

    const test_path = "test/default";
    const out_bin_path = "zig-out/bin";
    const test_dir = try fs.Dir.openIterableDir(fs.cwd(), test_path, .{ .no_follow = true });
    fs.Dir.makePath(fs.cwd(), out_bin_path) catch {};
    const out_bin_dir = try fs.Dir.openDir(fs.cwd(), out_bin_path, .{});
    try test_dir.dir.copyFile("run.sh", out_bin_dir, "run.sh", .{});
    var allocator = heap.page_allocator;
    var walker = try test_dir.walk(allocator);
    while (try walker.next()) |entry| {
        const name = entry.basename;
        if (mem.endsWith(u8, name, ".exp")) {
            try test_dir.dir.copyFile(name, out_bin_dir, name, .{});
            continue;
        }
        if (!mem.endsWith(u8, name, ".c")) {
            continue;
        }
        const exe_name = name[0 .. name.len - 2];
        var exe = b.addExecutable(.{
            .name = exe_name,
            .target = target,
            .optimize = optimize,
        });
        exe.linkLibC();
        exe.strip = true;
        exe.linkLibrary(static);
        exe.addIncludePath(.{ .path = "src/libsodium/include" });
        exe.addIncludePath(.{ .path = "test/quirks" });
        const full_path = try fmt.allocPrint(allocator, "{s}/{s}", .{ test_path, entry.path });
        exe.addCSourceFiles(&.{full_path}, &.{});

        if (enable_benchmarks) {
            exe.defineCMacro("BENCHMARKS", "1");
            var buf: [16]u8 = undefined;
            exe.defineCMacro("ITERATIONS", std.fmt.bufPrintIntToSlice(&buf, benchmarks_iterations, 10, .lower, .{}));
        }

        b.installArtifact(exe);
    }
}