const std = @import("std");
const version = @import("version.zig");

const usage =
    \\usage: nxdns <command>
    \\
    \\commands:
    \\  run       serve DNS
    \\  check     validate the configuration
    \\  export    write local records to stdout
    \\  import    read local records from stdin
    \\  version   print version information
    \\
;

const exit_ok = 0;
const exit_not_implemented = 2;
const exit_usage = 64;

pub fn main(init: std.process.Init) u8 {
    var args = init.minimal.args.iterate();
    _ = args.skip();
    const command = args.next() orelse return fail(init.io, usage);

    if (std.mem.eql(u8, command, "version")) {
        return print(init.io, "nxdns {s} ({s})\nzig {s}\n", .{
            version.string,
            version.git_commit,
            version.zig_version_string,
        });
    }

    for ([_][]const u8{ "run", "check", "export", "import" }) |known| {
        if (std.mem.eql(u8, command, known)) {
            _ = print(init.io, "not implemented\n", .{});
            return exit_not_implemented;
        }
    }

    return fail(init.io, usage);
}

fn print(io: std.Io, comptime format: []const u8, arguments: anytype) u8 {
    var buffer: [512]u8 = undefined;
    var file_writer = std.Io.File.stdout().writer(io, &buffer);
    file_writer.interface.print(format, arguments) catch return 1;
    file_writer.interface.flush() catch return 1;
    return exit_ok;
}

fn fail(io: std.Io, message: []const u8) u8 {
    var buffer: [512]u8 = undefined;
    var file_writer = std.Io.File.stderr().writer(io, &buffer);
    file_writer.interface.writeAll(message) catch {};
    file_writer.interface.flush() catch {};
    return exit_usage;
}