const std = @import("std");
const ProtocolError = @import("main.zig").ProtocolError;
const AuthType = @import("main.zig").AuthType;
const enum_from_int = @import("main.zig").enum_from_int;
const ClientError = @import("main.zig").ClientError;
const AuthenticationOk = @This();
const ByteArrayList = std.ArrayList(u8);

pub const Tag: u8 = 'R';

pub fn read(_: std.mem.Allocator, b: []const u8) !AuthenticationOk {
    if (b.len != 4) return ProtocolError.InvalidMessageLength;

    const auth_type = enum_from_int(AuthType, std.mem.readIntBig(u32, b[0..4])) orelse return ClientError.UnsupportedAuthType;
    if (auth_type != AuthType.AuthTypeOk) return ProtocolError.InvalidAuthType;
    return .{};
}

pub fn write(_: AuthenticationOk, _: std.mem.Allocator, stream_writer: anytype) !void {
    try stream_writer.writeByte(Tag);
    try stream_writer.writeIntBig(u32, 8);
    try stream_writer.writeIntBig(u32, @intFromEnum(AuthType.AuthTypeOk));
}

pub fn deinit(_: *AuthenticationOk, _: std.mem.Allocator) void {}

test "round trip" {
    const allocator = std.testing.allocator;
    var sm = AuthenticationOk{};
    defer sm.deinit(allocator);

    var bal = ByteArrayList.init(allocator);
    defer bal.deinit();
    try sm.write(allocator, bal.writer());

    var fbs = std.io.fixedBufferStream(bal.items);
    var reader = fbs.reader();
    const tag = try reader.readByte();
    try std.testing.expectEqual(Tag, tag);
    const len = try reader.readIntBig(u32);
    const buf = try allocator.alloc(u8, len - 4);
    defer allocator.free(buf);
    try reader.readNoEof(buf);
    var sm2 = try AuthenticationOk.read(allocator, buf);
    defer sm2.deinit(allocator);
}