using System.Text.RegularExpressions;

using MultiversalDiplomacy.Adjudicate;
using MultiversalDiplomacy.Model;
using MultiversalDiplomacy.Orders;

namespace MultiversalDiplomacy.Script;

public class AdjudicationQueryScriptHandler(
    Action<string> WriteLine,
    List<OrderValidation> validations,
    World world,
    IPhaseAdjudicator adjudicator)
    : IScriptHandler
{
    public string Prompt => "valid> ";

    public List<OrderValidation> Validations { get; } = validations;

    public World World { get; private set; } = world;

    public ScriptResult HandleInput(string input)
    {
        var args = input.Split(' ', 2, StringSplitOptions.RemoveEmptyEntries);
        if (args.Length == 0 || input.StartsWith('#'))
        {
            return ScriptResult.Succeed(this);
        }

        var command = args[0];
        switch (command)
        {
            case "---":
                WriteLine("Ready for orders");
                return ScriptResult.Succeed(new GameScriptHandler(WriteLine, World, adjudicator));

            case "assert" when args.Length == 1:
                WriteLine("Usage:");
                break;

            case "assert":
                return EvaluateAssertion(args[1]);

            case "status":
                throw new NotImplementedException();

            default:
                return ScriptResult.Fail($"Unrecognized command: \"{command}\"", this);
        }

        return ScriptResult.Succeed(this);
    }

    private ScriptResult EvaluateAssertion(string assertion)
    {
        var args = assertion.Split(' ', 2, StringSplitOptions.RemoveEmptyEntries);

        switch (args[0])
        {
            case "true":
                return ScriptResult.Succeed(this);

            case "false":
                return ScriptResult.Fail("assert false", this);

            case "order-valid":
            case "order-invalid":
                OrderParser re = new(World);
                Regex prov = new($"^{re.FullLocation}$", RegexOptions.IgnoreCase);
                Match match = prov.Match(args[1]);
                if (!match.Success) return ScriptResult.Fail($"Could not parse province from \"{args[1]}\"", this);

                string timeline = match.Groups[1].Length > 0
                    ? match.Groups[1].Value
                    : Season.First.Timeline;
                var seasonsInTimeline = World.Timelines.Seasons.Where(season => season.Timeline == timeline);
                if (!seasonsInTimeline.Any()) return ScriptResult.Fail($"No seasons in timeline {timeline}", this);
                
                int turn = match.Groups[4].Length > 0
                    ? int.Parse(match.Groups[4].Value)
                    // If turn is unspecified, use the second-latest turn in the timeline,
                    // since we want to assert against the subjects of the orders just adjudicated,
                    // and adjudication created a new set of seasons.
                    : seasonsInTimeline.Max(season => season.Turn) - 1;
                Season season = new(timeline, turn);

                Province province = World.Map.Provinces.Single(province => province.Is(match.Groups[2].Value));

                var matching = Validations.Where(val
                    => val.Order is UnitOrder order
                    && order.Unit.Season == season
                    && World.Map.GetLocation(order.Unit.Location).ProvinceName == province.Name);
                if (!matching.Any()) return ScriptResult.Fail("No matching validations");

                if (args[0] == "order-valid" && !matching.First().Valid) {
                    return ScriptResult.Fail($"Order \"{matching.First().Order} is invalid");
                }
                if (args[0] == "order-invalid" && matching.First().Valid) {
                    return ScriptResult.Fail($"Order \"{matching.First().Order} is valid");
                }
                return ScriptResult.Succeed(this);

            case "has-past":
                Regex hasPast = new($"^([a-z]+[0-9]+)>([a-z]+[0-9]+)$");
                Match hpMatch = hasPast.Match(args[1]);
                if (!hpMatch.Success) return ScriptResult.Fail("Expected format s1>s2", this);

                Season future = new(hpMatch.Groups[1].Value);
                if (!World.Timelines.Pasts.TryGetValue(future.Key, out Season? actual)) {
                    return ScriptResult.Fail($"No such season \"{future}\"");
                }

                Season expected = new(hpMatch.Groups[2].Value);
                if (actual != expected) return ScriptResult.Fail(
                    $"Expected past of {future} to be {expected}, but it was {actual}");
                return ScriptResult.Succeed(this);

            case "holds":
                // Assert a unit successfully held

            case "dislodged":
                // Assert a unit was dislodged

            case "moves":
                // Assert a unit successfully moved

            case "no-move":
                // Assert a unit did not move

            case "supports":
                // Assert a unit's support was given

            case "cut":
                // Assert a unit's support was cut

            default:
                return ScriptResult.Fail($"Unknown assertion \"{args[0]}\"", this);
        }
    }
}