using EchoHub.Server.Irc;
using Xunit;

namespace EchoHub.Tests.Irc;

public class IrcMessageTests
{
    [Fact]
    public void Parse_SimpleCommand_ExtractsCommand()
    {
        var msg = IrcMessage.Parse("PING");
        Assert.Equal("PING", msg.Command);
        Assert.Null(msg.Prefix);
        Assert.Empty(msg.Parameters);
    }

    [Fact]
    public void Parse_CommandWithOneParam_ExtractsParam()
    {
        var msg = IrcMessage.Parse("NICK alice");
        Assert.Equal("NICK", msg.Command);
        Assert.Single(msg.Parameters);
        Assert.Equal("alice", msg.Parameters[0]);
    }

    [Fact]
    public void Parse_CommandWithTrailing_ExtractsTrailingAsLastParam()
    {
        var msg = IrcMessage.Parse("PRIVMSG #general :Hello world!");
        Assert.Equal("PRIVMSG", msg.Command);
        Assert.Equal(2, msg.Parameters.Count);
        Assert.Equal("#general", msg.Parameters[0]);
        Assert.Equal("Hello world!", msg.Parameters[1]);
        Assert.Equal("Hello world!", msg.Trailing);
    }

    [Fact]
    public void Parse_MessageWithPrefix_ExtractsPrefix()
    {
        var msg = IrcMessage.Parse(":alice!alice@echohub PRIVMSG #general :hi");
        Assert.Equal("alice!alice@echohub", msg.Prefix);
        Assert.Equal("PRIVMSG", msg.Command);
        Assert.Equal(2, msg.Parameters.Count);
        Assert.Equal("#general", msg.Parameters[0]);
        Assert.Equal("hi", msg.Parameters[1]);
    }

    [Fact]
    public void Parse_MultipleParams_ExtractsAll()
    {
        var msg = IrcMessage.Parse("USER alice 0 * :Alice Smith");
        Assert.Equal("USER", msg.Command);
        Assert.Equal(4, msg.Parameters.Count);
        Assert.Equal("alice", msg.Parameters[0]);
        Assert.Equal("0", msg.Parameters[1]);
        Assert.Equal("*", msg.Parameters[2]);
        Assert.Equal("Alice Smith", msg.Parameters[3]);
    }

    [Fact]
    public void Parse_PingWithToken_ExtractsToken()
    {
        var msg = IrcMessage.Parse("PING :server.example.com");
        Assert.Equal("PING", msg.Command);
        Assert.Single(msg.Parameters);
        Assert.Equal("server.example.com", msg.Parameters[0]);
    }

    [Fact]
    public void Parse_CapLs_ParsesSubcommand()
    {
        var msg = IrcMessage.Parse("CAP LS 302");
        Assert.Equal("CAP", msg.Command);
        Assert.Equal(2, msg.Parameters.Count);
        Assert.Equal("LS", msg.Parameters[0]);
        Assert.Equal("302", msg.Parameters[1]);
    }

    [Fact]
    public void Parse_CapReqWithTrailing_ParsesSasl()
    {
        var msg = IrcMessage.Parse("CAP REQ :sasl");
        Assert.Equal("CAP", msg.Command);
        Assert.Equal(2, msg.Parameters.Count);
        Assert.Equal("REQ", msg.Parameters[0]);
        Assert.Equal("sasl", msg.Parameters[1]);
    }

    [Fact]
    public void Parse_JoinMultipleChannels_ExtractsCsv()
    {
        var msg = IrcMessage.Parse("JOIN #general,#random");
        Assert.Equal("JOIN", msg.Command);
        Assert.Single(msg.Parameters);
        Assert.Equal("#general,#random", msg.Parameters[0]);
    }

    [Fact]
    public void Parse_PartWithReason_ExtractsReason()
    {
        var msg = IrcMessage.Parse("PART #general :Leaving for now");
        Assert.Equal("PART", msg.Command);
        Assert.Equal(2, msg.Parameters.Count);
        Assert.Equal("#general", msg.Parameters[0]);
        Assert.Equal("Leaving for now", msg.Parameters[1]);
    }

    [Fact]
    public void Parse_EmptyTrailing_ExtractsEmptyString()
    {
        var msg = IrcMessage.Parse("PRIVMSG #general :");
        Assert.Equal("PRIVMSG", msg.Command);
        Assert.Equal(2, msg.Parameters.Count);
        Assert.Equal("#general", msg.Parameters[0]);
        Assert.Equal("", msg.Parameters[1]);
    }

    [Fact]
    public void Parse_TrailingWithColons_PreservesColons()
    {
        var msg = IrcMessage.Parse("PRIVMSG #general :time is 12:30:00");
        Assert.Equal("time is 12:30:00", msg.Parameters[1]);
    }

    [Fact]
    public void Parse_CrLfTrimmed()
    {
        var msg = IrcMessage.Parse("PING\r\n");
        Assert.Equal("PING", msg.Command);
        Assert.Empty(msg.Parameters);
    }

    [Fact]
    public void Parse_ExtraSpaces_Handled()
    {
        var msg = IrcMessage.Parse("NICK   alice");
        Assert.Equal("NICK", msg.Command);
        Assert.Single(msg.Parameters);
        Assert.Equal("alice", msg.Parameters[0]);
    }

    [Fact]
    public void Parse_Authenticate_Base64Payload()
    {
        var payload = Convert.ToBase64String(System.Text.Encoding.UTF8.GetBytes("\0alice\0secret"));
        var msg = IrcMessage.Parse($"AUTHENTICATE {payload}");
        Assert.Equal("AUTHENTICATE", msg.Command);
        Assert.Single(msg.Parameters);
        Assert.Equal(payload, msg.Parameters[0]);
    }

    [Fact]
    public void Parse_PassCommand_ExtractsPassword()
    {
        var msg = IrcMessage.Parse("PASS mysecretpassword");
        Assert.Equal("PASS", msg.Command);
        Assert.Single(msg.Parameters);
        Assert.Equal("mysecretpassword", msg.Parameters[0]);
    }

    [Fact]
    public void Parse_QuitWithMessage_ExtractsMessage()
    {
        var msg = IrcMessage.Parse("QUIT :Goodbye!");
        Assert.Equal("QUIT", msg.Command);
        Assert.Single(msg.Parameters);
        Assert.Equal("Goodbye!", msg.Parameters[0]);
    }

    [Fact]
    public void Trailing_NoParams_ReturnsNull()
    {
        var msg = IrcMessage.Parse("PING");
        Assert.Null(msg.Trailing);
    }

    [Fact]
    public void Trailing_WithParams_ReturnsLastParam()
    {
        var msg = IrcMessage.Parse("MODE #channel +o alice");
        Assert.Equal("alice", msg.Trailing);
    }
}