const std = @import("std");
const fs = std.fs;
const io = std.io;
const mem = std.mem;
const os = std.os;
const ArrayList = std.ArrayList;
const Allocator = std.mem.Allocator;
const GeneralPurposeAllocator = std.heap.GeneralPurposeAllocator;

const flags = @import("../flags.zig");
const User = @import("../User.zig");
const Group = @import("../Group.zig");
const Corpus = @import("../Corpus.zig");
const DB = @import("../DB.zig");

const usage =
    \\usage: turbonss-unix2db [options]
    \\
    \\  -h          Print this help message and exit
    \\  --passwd    Path to passwd file (default: ./passwd)
    \\  --group     Path to group file (default: ./group)
    \\
;

pub fn main() !void {
    // This line is here because of https://github.com/ziglang/zig/issues/7807
    const argv: []const [*:0]const u8 = os.argv;
    const gpa = GeneralPurposeAllocator(.{});

    const return_code = execute(gpa, argv[1..]) catch |err| {
        try io.getStdErr().writeAll("uncaught error: {s}\n", @intToError(err));
        os.exit(1);
    };

    os.exit(return_code);
}

fn execute(
    allocator: Allocator,
    stderr: anytype,
    argv: []const [*:0]const u8,
) !u8 {
    const result = flags.parse(argv, &[_]flags.Flag{
        .{ .name = "-h", .kind = .boolean },
        .{ .name = "--passwd", .kind = .arg },
        .{ .name = "--group", .kind = .arg },
        .{ .name = "--output", .kind = .arg },
    }) catch {
        try stderr.writeAll(usage);
        return 1;
    };

    if (result.boolFlag("-h")) {
        try io.getStdOut().writeAll(usage);
        return 0;
    }

    if (result.args.len != 0) {
        try stderr.print("ERROR: unknown option '{s}'\n", .{result.args[0]});
        try stderr.writeAll(usage);
        return 1;
    }

    const passwdFname = result.argFlag("--passwd") orelse "./passwd";
    const groupFname = result.argFlag("--group") orelse "./group";
    const outFile = result.argFlag("--output") orelse "./db.turbo";

    std.debug.print("passwd file name: {s}\n", .{passwdFname});
    var passwdFile = try fs.cwd().openFile(passwdFname, .{ .mode = .read_only });
    defer passwdFile.close();
    var groupFile = try fs.cwd().openFile(groupFname, .{ .mode = .read_only });
    defer groupFile.close();

    var users = try User.fromReader(allocator, passwdFile.reader());
    defer for (users) |*user| user.deinit(allocator);
    var groups = try Group.fromReader(allocator, groupFile.reader());
    defer for (groups) |*group| group.deinit(allocator);

    var corpus = try Corpus.init(allocator, users, groups);
    defer corpus.deinit();
    var db = try DB.fromCorpus(allocator, &corpus);
    defer db.deinit(allocator);

    const fd = try os.open(outFile, os.O.WRONLY | os.O.TRUNC | os.O.CREAT, 0644);
    errdefer os.close(fd);

    const len = try os.writev(fd, db.iov().constSlice());
    try os.fsync(fd);
    os.close(fd);

    try stderr.print("total {d} bytes. groups={d} users={d}\n", .{
        len,
        users.len,
        groups.len,
    });
    return 0;
}

const testing = std.testing;

test "invalid argument" {
    const allocator = testing.allocator;
    const args = &[_][*:0]const u8{"--invalid-argument"};
    var stderr = ArrayList(u8).init(allocator);
    defer stderr.deinit();

    const exit_code = try execute(allocator, stderr.writer(), args[0..]);
    try testing.expectEqual(@as(u8, 1), exit_code);
    try testing.expect(mem.startsWith(
        u8,
        stderr.items,
        "ERROR: unknown option '--invalid-argument'",
    ));
}

test "smoke test" {
    if (true) return error.SkipZigTest;

    const allocator = testing.allocator;
    var stderr = ArrayList(u8).init(allocator);
    defer stderr.deinit();

    var corpus = try Corpus.testCorpus(allocator);
    defer corpus.deinit();

    var tmp = testing.tmpDir(.{});
    errdefer tmp.cleanup();

    const tmp_path = blk: {
        const relative_path = try fs.path.join(allocator, &[_][]const u8{
            "zig-cache",
            "tmp",
            tmp.sub_path[0..],
        });
        const real_path = try fs.realpathAlloc(allocator, relative_path);
        allocator.free(relative_path);
        break :blk real_path;
    };
    defer allocator.free(tmp_path);

    const passwdPath = try fs.path.joinZ(allocator, &[_][]const u8{ tmp_path, "passwd" });
    defer allocator.free(passwdPath);
    const groupPath = try fs.path.joinZ(allocator, &[_][]const u8{ tmp_path, "group" });
    defer allocator.free(groupPath);
    const outPath = try fs.path.joinZ(allocator, &[_][]const u8{ tmp_path, "tmp.turbo" });
    defer allocator.free(outPath);

    const passwd_fd = try os.open(passwdPath, os.O.CREAT | os.O.WRONLY, 0o644);
    const group_fd = try os.open(groupPath, os.O.CREAT | os.O.WRONLY, 0o644);

    var i: usize = 0;
    while (i < corpus.users.len) : (i += 1) {
        const user = corpus.users.get(i);
        const line = user.toLine();
        _ = try os.write(passwd_fd, line.constSlice());
    }
    os.close(passwd_fd);

    var group_writer = (fs.File{ .handle = group_fd }).writer();
    i = 0;
    while (i < corpus.groups.len) : (i += 1)
        try corpus.groups.get(i).writeTo(group_writer);
    os.close(group_fd);

    const args = &[_][*:0]const u8{
        "--passwd", passwdPath,
        "--group",  groupPath,
        "--output", outPath,
    };
    const exit_code = try execute(allocator, stderr.writer(), args);

    try testing.expectEqual(@as(u8, 0), exit_code);
}