const std = @import("std");

const VERSION = "4.0";

const main_targets: []const std.Target.Query = &[_]std.Target.Query{
    .{ .cpu_arch = .aarch64, .os_tag = .macos, .abi = null },
    .{ .cpu_arch = .x86_64, .os_tag = .macos, .abi = null },
    .{ .cpu_arch = .aarch64, .os_tag = .linux, .abi = .musl },
    .{ .cpu_arch = .x86_64, .os_tag = .linux, .abi = .musl },
    .{ .cpu_arch = .x86_64, .os_tag = .windows, .abi = .gnu },
};

const supported_targets: []const std.Target.Query = &[_]std.Target.Query{
    .{ .cpu_arch = .aarch64, .os_tag = .macos, .abi = null },
    .{ .cpu_arch = .x86_64, .os_tag = .macos, .abi = null },
    .{ .cpu_arch = .aarch64, .os_tag = .linux, .abi = .musl },
    .{ .cpu_arch = .x86_64, .os_tag = .linux, .abi = .musl },
    .{ .cpu_arch = .aarch64, .os_tag = .linux, .abi = .gnu },
    .{ .cpu_arch = .x86_64, .os_tag = .linux, .abi = .gnu },
    .{ .cpu_arch = .x86_64, .os_tag = .linux, .abi = .gnu, .glibc_version = std.SemanticVersion{ .major = 2, .minor = 27, .patch = 0 } },
    .{ .cpu_arch = .x86_64, .os_tag = .windows, .abi = .gnu },
};

const targets: []const std.Target.Query = main_targets;

const BuildCfg = struct {
    version: []const u8,
    pace: []const u8,
    binary_name: []const u8,
    flags: []const []const u8 = &.{},
    include_test_steps: bool = true,
    cpu_dbg: bool = false,
    mem_dbg: bool = false,
    c3dbg: bool = false,
    snapshot_validation: bool = false,
    ubsan: bool = false,
    asan: bool = false,
    tracy_enable: bool = false,
    tracy_callstack: bool = false,
    tracy_no_exit: bool = false,
};

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

    //
    // Additional Project-Specific Options
    //

    const all = b.option(bool, "all", "Build all targets") orelse false;

    const release = b.option(bool, "release", "Build for release") orelse false;
    if (release) optimize = .ReleaseFast;

    const Pace = enum { once, live, soon, edge };
    const pace = @tagName(b.option(
        Pace,
        "pace",
        "Release train (Default: once)",
    ) orelse if (release) Pace.live else Pace.once);

    const copts: []const []const u8 = b.option(
        []const []const u8,
        "copt",
        "Provide additional compiler flags",
    ) orelse &.{};

    const cpu_dbg = b.option(
        bool,
        "cpu-dbg",
        "Enable cpu debug mode (-DU3_CPU_DEBUG)",
    ) orelse false;

    const mem_dbg = b.option(
        bool,
        "mem-dbg",
        "Enable memory debug mode (-DU3_MEMORY_DEBUG)",
    ) orelse false;

    const c3dbg = b.option(
        bool,
        "c3dbg",
        "Enable debug assertions (-DC3DBG)",
    ) orelse false;

    const snapshot_validation = b.option(
        bool,
        "snapshot-validation",
        "Enable snapshot validation (-DU3_SNAPSHOT_VALIDATION)",
    ) orelse false;

    const binary_name = b.option(
        []const u8,
        "binary-name",
        "Binary name (Default: urbit)",
    ) orelse "urbit";

    const asan = if (target.query.isNative())
        b.option(
            bool,
            "asan",
            "Enable address sanitizer (native only, requires llvm@18)",
        ) orelse false
    else
        false;

    const ubsan = if (target.query.isNative())
        b.option(
            bool,
            "ubsan",
            "Enable undefined behavior sanitizer (native only, requires llvm@18)",
        ) orelse false
    else
        false;

    const tracy_enable = b.option(bool, "tracy", "Enable Tracy profiler") orelse false;
    const tracy_callstack = b.option(bool, "tracy-callstack", "Enable Tracy callstack capture") orelse false;
    const tracy_no_exit = b.option(bool, "tracy-no-exit", "Wait for profiler connection before exiting") orelse false;

    // Parse short git rev
    var file = try std.fs.cwd().openFile(".git/logs/HEAD", .{});
    defer file.close();
    var buf_reader = std.io.bufferedReader(file.reader());
    var in_stream = buf_reader.reader();
    var buf: [1024]u8 = undefined;
    var last_line: [1024]u8 = undefined;
    while (try in_stream.readUntilDelimiterOrEof(&buf, '\n')) |line| {
        if (line.len > 0)
            last_line = buf;
    }
    const git_rev = buf[41..51];

    // Binary version
    const version = if (!release)
        VERSION ++ "-" ++ git_rev
    else
        VERSION;

    //
    // Build
    //

    const build_cfg: BuildCfg = .{
        .version = version,
        .pace = pace,
        .flags = copts,
        .binary_name = binary_name,
        .cpu_dbg = cpu_dbg,
        .mem_dbg = mem_dbg,
        .c3dbg = c3dbg,
        .snapshot_validation = snapshot_validation,
        .asan = asan,
        .ubsan = ubsan,
        .tracy_enable = tracy_enable,
        .tracy_callstack = tracy_callstack,
        .tracy_no_exit = tracy_no_exit,
        .include_test_steps = !all,
    };

    if (all) {
        for (targets) |t| {
            try buildBinary(b, b.resolveTargetQuery(t), optimize, build_cfg);
        }
    } else {
        const t = target.result;
        try buildBinary(
            b,
            if (t.os.tag == .linux and
                target.query.isNative() and
                !asan and !ubsan)
                b.resolveTargetQuery(.{ .abi = .musl })
            else
                target,
            optimize,
            build_cfg,
        );
    }
}

fn buildBinary(
    b: *std.Build,
    target: std.Build.ResolvedTarget,
    optimize: std.builtin.OptimizeMode,
    cfg: BuildCfg,
) !void {
    const t = target.result;

    //
    // Global C Opts
    // TODO: Propagate these to all 3rd party dependencies
    //

    var global_flags = std.ArrayList([]const u8).init(b.allocator);
    defer global_flags.deinit();

    try global_flags.appendSlice(cfg.flags);
    try global_flags.appendSlice(&.{
        "-g3",
        "-Wall",
        "-Werror",
    });

    if (!cfg.asan and !cfg.ubsan) {
        try global_flags.appendSlice(&.{
            "-fno-sanitize=all",
        });
        if (t.os.tag == .windows) {
            try global_flags.appendSlice(&.{
                "-Qunused-arguments",
            });
        }
    }

    if (cfg.asan and !cfg.ubsan)
        try global_flags.appendSlice(&.{
            "-Wno-deprecated",
            "-fsanitize=address",
            "-fno-sanitize=undefined",
            "-fno-sanitize-trap=undefined",
        });

    if (!cfg.asan and cfg.ubsan)
        try global_flags.appendSlice(&.{
            "-fsanitize=undefined",
            "-fno-sanitize-trap=undefined",
        });

    if (cfg.asan and cfg.ubsan)
        try global_flags.appendSlice(&.{
            "-Wno-deprecated",
            "-fsanitize=address",
            "-fsanitize=undefined",
            "-fno-sanitize-trap=undefined",
        });

    //
    //  C Opts for Urbit PKGs And Binary
    //

    var urbit_flags = std.ArrayList([]const u8).init(b.allocator);
    defer urbit_flags.deinit();

    try urbit_flags.appendSlice(global_flags.items);
    try urbit_flags.appendSlice(&.{
        "-Wno-deprecated-non-prototype",
        "-Wno-gnu-binary-literal",
        "-Wno-gnu-empty-initializer",
        "-Wno-gnu-statement-expression",
        "-Wno-unused-variable",
        "-Wno-unused-function",
        "-Wno-gnu",
        "-fno-omit-frame-pointer",
        "-fms-extensions",
        "-DU3_GUARD_PAGE", // pkg_noun
        "-DU3_OS_ENDIAN_little=1", // pkg_c3
        "-DU3_OS_PROF=1", // pkg_c3
    });

    if (cfg.cpu_dbg)
        try urbit_flags.appendSlice(&.{"-DU3_CPU_DEBUG"});

    if (cfg.mem_dbg)
        try urbit_flags.appendSlice(&.{"-DU3_MEMORY_DEBUG"});

    if (cfg.c3dbg)
        try urbit_flags.appendSlice(&.{"-DC3DBG"});

    if (cfg.snapshot_validation)
        try urbit_flags.appendSlice(&.{"-DU3_SNAPSHOT_VALIDATION"});

    if (cfg.tracy_enable) {
        try urbit_flags.appendSlice(&.{"-DTRACY_ENABLE"});
        if (cfg.tracy_callstack) {
            try urbit_flags.appendSlice(&.{"-DTRACY_CALLSTACK"});
        }
        if (cfg.tracy_no_exit) {
            try urbit_flags.appendSlice(&.{"-DTRACY_NO_EXIT"});
        }
    }

    if (t.cpu.arch == .aarch64) {
        try urbit_flags.appendSlice(&.{
            "-DU3_CPU_aarch64=1",
        });
    }

    if (t.os.tag == .macos) {
        try urbit_flags.appendSlice(&.{
            "-DU3_OS_osx=1",
            "-DENT_GETENTROPY_SYSRANDOM", // pkg_ent
        });
    }

    if (t.os.tag == .linux) {
        try urbit_flags.appendSlice(&.{
            "-DU3_OS_linux=1",
            "-DENT_GETENTROPY_UNISTD", //pkg_ent
        });
    }

    if (t.os.tag == .windows) {
        try urbit_flags.appendSlice(&.{
            "-DU3_OS_windows=1",
            "-DWIN32_LEAN_AND_MEAN",
            "-DENT_GETENTROPY_BCRYPTGENRANDOM", // pkg_ent
            "-DO_CLOEXEC=0",
            "-DH2O_NO_UNIX_SOCKETS",
            "-DH2O_NO_HTTP3",
            "-DH2O_NO_REDIS",
            "-DH2O_NO_MEMCACHED",
            "-DCURL_STATICLIB",
        });
    }

    //
    // Dependencies
    //

    const copts: []const []const u8 = urbit_flags.items;

    const pkg_c3 = b.dependency("pkg_c3", .{
        .target = target,
        .optimize = optimize,
        .copt = copts,
    });

    const pkg_ent = b.dependency("pkg_ent", .{
        .target = target,
        .optimize = optimize,
        .copt = copts,
    });

    const pkg_ur = b.dependency("pkg_ur", .{
        .target = target,
        .optimize = optimize,
        .copt = copts,
    });

    const pkg_noun = b.dependency("pkg_noun", .{
        .target = target,
        .optimize = optimize,
        .copt = copts,
    });

    const pkg_past = b.dependency("pkg_past", .{
        .target = target,
        .optimize = optimize,
        .copt = copts,
    });

    const pkg_vere = b.dependency("pkg_vere", .{
        .target = target,
        .optimize = optimize,
        .copt = copts,
        .pace = cfg.pace,
        .version = cfg.version,
    });

    const curl = b.dependency("curl", .{
        .target = target,
        .optimize = optimize,
    });

    const gmp = b.dependency("gmp", .{
        .target = target,
        .optimize = optimize,
    });

    const h2o = b.dependency("h2o", .{
        .target = target,
        .optimize = optimize,
    });

    const libuv = b.dependency("libuv", .{
        .target = target,
        .optimize = optimize,
    });

    const lmdb = b.dependency("lmdb", .{
        .target = target,
        .optimize = optimize,
    });

    const natpmp = b.dependency("natpmp", .{
        .target = target,
        .optimize = optimize,
    });

    const openssl = b.dependency("openssl", .{
        .target = target,
        .optimize = optimize,
    });

    const sigsegv = b.dependency("sigsegv", .{
        .target = target,
        .optimize = optimize,
    });

    const urcrypt = b.dependency("urcrypt", .{
        .target = target,
        .optimize = optimize,
    });

    const whereami = b.dependency("whereami", .{
        .target = target,
        .optimize = optimize,
    });

    const zlib = b.dependency("zlib", .{
        .target = target,
        .optimize = optimize,
    });

    const wasm3 = b.dependency("wasm3", .{
        .target = target,
        .optimize = optimize,
    });

    const tracy = if (cfg.tracy_enable) b.dependency("tracy", .{
        .target = target,
        .optimize = optimize,
    }) else null;

    //
    // Build Artifact
    //

    const urbit = b.addExecutable(.{
        .name = cfg.binary_name,
        .target = target,
        .optimize = optimize,
    });

    if (t.os.tag == .windows) {
        urbit.stack_size = 67108864;
    } else {
        urbit.stack_size = 0;
    }

    if (t.os.tag == .windows) {
        urbit.linkSystemLibrary("ws2_32"); // WSA*, socket, htons, inet_*, gethostbyname, etc.
    }

    const target_query: std.Target.Query = .{
        .cpu_arch = t.cpu.arch,
        .os_tag = t.os.tag,
        .abi = t.abi,
        .os_version_min = .none,
        .os_version_max = .none,
    };
    const target_output = b.addInstallArtifact(urbit, .{
        .dest_dir = .{
            .override = .{
                .custom = try target_query.zigTriple(b.allocator),
            },
        },
    });
    b.getInstallStep().dependOn(&target_output.step);

    if (target.result.os.tag.isDarwin() and !target.query.isNative()) {
        const macos_sdk = b.lazyDependency("macos_sdk", .{
            .target = target,
            .optimize = optimize,
        });
        if (macos_sdk != null) {
            urbit.addSystemIncludePath(macos_sdk.?.path("usr/include"));
            urbit.addLibraryPath(macos_sdk.?.path("usr/lib"));
            urbit.addFrameworkPath(macos_sdk.?.path("System/Library/Frameworks"));
        }
    }

    urbit.linkLibC();

    urbit.linkLibrary(pkg_vere.artifact("vere"));
    urbit.linkLibrary(pkg_noun.artifact("noun"));
    urbit.linkLibrary(pkg_past.artifact("past"));
    urbit.linkLibrary(pkg_c3.artifact("c3"));
    urbit.linkLibrary(pkg_ur.artifact("ur"));

    urbit.linkLibrary(gmp.artifact("gmp"));

    urbit.linkLibrary(h2o.artifact("h2o"));
    urbit.linkLibrary(curl.artifact("curl"));
    urbit.linkLibrary(libuv.artifact("libuv"));
    urbit.linkLibrary(lmdb.artifact("lmdb"));
    urbit.linkLibrary(openssl.artifact("ssl"));
    if (t.os.tag != .windows)
        urbit.linkLibrary(sigsegv.artifact("sigsegv"));
    urbit.linkLibrary(urcrypt.artifact("urcrypt"));
    urbit.linkLibrary(whereami.artifact("whereami"));
    urbit.linkLibrary(wasm3.artifact("wasm3"));

    if (cfg.tracy_enable) {
        urbit.linkLibrary(tracy.?.artifact("tracy"));
        urbit.addIncludePath(tracy.?.path(""));
    }

    if (t.os.tag.isDarwin()) {
        // Requires llvm@18 homebrew installation
        if (cfg.asan or cfg.ubsan)
            urbit.addLibraryPath(.{
                .cwd_relative = "/opt/homebrew/opt/llvm@18/lib/clang/18/lib/darwin",
            });
        if (cfg.asan) urbit.linkSystemLibrary("clang_rt.asan_osx_dynamic");
        if (cfg.ubsan) urbit.linkSystemLibrary("clang_rt.ubsan_osx_dynamic");
    }

    if (t.os.tag == .linux) {
        // Requires llvm-18 and clang-18 installation
        if (cfg.asan or cfg.ubsan)
            urbit.addLibraryPath(.{
                .cwd_relative = "/usr/lib/clang/18/lib/linux",
            });
        if (t.cpu.arch == .x86_64) {
            if (cfg.asan) urbit.linkSystemLibrary("clang_rt.asan-x86_64");
            if (cfg.ubsan)
                urbit.linkSystemLibrary("clang_rt.ubsan_standalone-x86_64");
        }
        if (t.cpu.arch == .aarch64) {
            if (cfg.asan) urbit.linkSystemLibrary("clang_rt.asan-aarch64");
            if (cfg.ubsan)
                urbit.linkSystemLibrary("clang_rt.ubsan_standalone-aarch64");
        }
    }

    urbit.addCSourceFiles(.{
        .root = b.path("pkg/vere"),
        .files = &.{
            "main.c",
        },
        .flags = urbit_flags.items,
    });

    // CI needs generated version.h so we install libvere as a quick fix
    const vere_install = b.addInstallArtifact(pkg_vere.artifact("vere"), .{});
    b.getInstallStep().dependOn(&vere_install.step);

    //
    // Tests
    //

    if (cfg.include_test_steps) {
        const noun_test_deps = &.{
            pkg_noun.artifact("noun"),
            pkg_c3.artifact("c3"),
            gmp.artifact("gmp"),
        };
        const vere_test_deps = &.{
            pkg_vere.artifact("vere"),
            pkg_noun.artifact("noun"),
            pkg_ur.artifact("ur"),
            pkg_ent.artifact("ent"),
            pkg_c3.artifact("c3"),
            gmp.artifact("gmp"),
            libuv.artifact("libuv"),
            lmdb.artifact("lmdb"),
            natpmp.artifact("natpmp"),
            zlib.artifact("z"),
        };
        const tests = [_]struct {
            name: []const u8,
            file: []const u8,
            deps: []const *std.Build.Step.Compile,
        }{
            // pkg_ur
            .{
                .name = "ur-test",
                .file = "pkg/ur/tests.c",
                .deps = &.{pkg_ur.artifact("ur")},
            },
            // pkg_ent
            .{
                .name = "ent-test",
                .file = "pkg/ent/tests.c",
                .deps = &.{pkg_ent.artifact("ent")},
            },
            // pkg_noun
            .{
                .name = "palloc-test",
                .file = "pkg/noun/palloc_tests.c",
                .deps = noun_test_deps,
            },
            .{
                .name = "equality-test",
                .file = "pkg/noun/equality_tests.c",
                .deps = noun_test_deps,
            },
            .{
                .name = "hashtable-test",
                .file = "pkg/noun/hashtable_tests.c",
                .deps = noun_test_deps,
            },
            .{
                .name = "hamt-test",
                .file = "pkg/vere/hamt_test.c",
                .deps = vere_test_deps,
            },
            .{
                .name = "jets-test",
                .file = "pkg/noun/jets_tests.c",
                .deps = noun_test_deps,
            },
            .{
                .name = "nock-test",
                .file = "pkg/noun/nock_tests.c",
                .deps = noun_test_deps,
            },
            .{
                .name = "retrieve-test",
                .file = "pkg/noun/retrieve_tests.c",
                .deps = noun_test_deps,
            },
            .{
                .name = "serial-test",
                .file = "pkg/noun/serial_tests.c",
                .deps = noun_test_deps,
            },
            .{
                .name = "life-test",
                .file = "pkg/noun/life_test.c",
                .deps = noun_test_deps,
            },
            // pkg_vere
            .{
                .name = "ames-test",
                .file = "pkg/vere/ames_tests.c",
                .deps = vere_test_deps,
            },
            .{
                .name = "boot-test",
                .file = "pkg/vere/boot_tests.c",
                .deps = vere_test_deps,
            },
            .{
                .name = "solid-boot-test",
                .file = "pkg/vere/solid_boot_test.c",
                .deps = vere_test_deps,
            },
            .{
                .name = "newt-test",
                .file = "pkg/vere/newt_tests.c",
                .deps = vere_test_deps,
            },
            .{
                .name = "vere-noun-test",
                .file = "pkg/vere/noun_tests.c",
                .deps = vere_test_deps,
            },
            .{
                .name = "unix-test",
                .file = "pkg/vere/unix_tests.c",
                .deps = vere_test_deps,
            },
            .{
                .name = "benchmarks",
                .file = "pkg/vere/benchmarks.c",
                .deps = vere_test_deps,
            },
            .{
                .name = "pact-test",
                .file = "pkg/vere/io/mesa/pact_test.c",
                .deps = vere_test_deps,
            },
            .{
                .name = "tracy-test",
                .file = "pkg/vere/tracy_test.c",
                .deps = vere_test_deps,
            },
        };

        for (tests) |tst| {
            const test_step =
                b.step(tst.name, b.fmt("Build & run: {s}", .{tst.file}));
            const test_exe = b.addExecutable(.{
                .name = tst.name,
                .target = target,
                .optimize = optimize,
            });

            if (t.os.tag.isDarwin() and !target.query.isNative()) {
                const macos_sdk = b.lazyDependency("macos_sdk", .{
                    .target = target,
                    .optimize = optimize,
                });
                if (macos_sdk != null) {
                    test_exe.addSystemIncludePath(macos_sdk.?.path("usr/include"));
                    test_exe.addLibraryPath(macos_sdk.?.path("usr/lib"));
                    test_exe.addFrameworkPath(macos_sdk.?.path("System/Library/Frameworks"));
                }
            }

            if (t.os.tag == .windows) {
                test_exe.linkSystemLibrary("ws2_32");
            }

            if (t.os.tag.isDarwin()) {
                // Requires llvm@18 homebrew installation
                if (cfg.asan or cfg.ubsan)
                    test_exe.addLibraryPath(.{
                        .cwd_relative = "/opt/homebrew/opt/llvm@18/lib/clang/18/lib/darwin",
                    });
                if (cfg.asan)  test_exe.linkSystemLibrary("clang_rt.asan_osx_dynamic");
                if (cfg.ubsan) test_exe.linkSystemLibrary("clang_rt.ubsan_osx_dynamic");
            }

            test_exe.stack_size = 0;
            test_exe.linkLibC();
            for (tst.deps) |dep| {
                test_exe.linkLibrary(dep);
            }
            if (cfg.tracy_enable) {
                test_exe.linkLibrary(tracy.?.artifact("tracy"));
                test_exe.addIncludePath(tracy.?.path(""));
            }
            test_exe.addCSourceFiles(.{
                .files = &.{tst.file},
                .flags = urbit_flags.items,
            });
            const exe_install = b.addInstallArtifact(test_exe, .{});
            const run_unit_tests = b.addRunArtifact(test_exe);
            if ( t.os.tag.isDarwin() and (cfg.asan or cfg.ubsan) ) {
                //  disable libmalloc warnings
                run_unit_tests.setEnvironmentVariable("MallocNanoZone", "0");
            }
            run_unit_tests.skip_foreign_checks = true;
            test_step.dependOn(&run_unit_tests.step);
            test_step.dependOn(&exe_install.step);
        }
    }
}