using System.Text.RegularExpressions;

using MultiversalDiplomacy.Model;
using MultiversalDiplomacy.Orders;

namespace MultiversalDiplomacy.Script;

public class GameScriptHandler(World world, bool strict = false) : IScriptHandler
{
    public string Prompt => "orders> ";

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

    /// <summary>
    /// Whether unsuccessful commands should terminate the script.
    /// </summary>
    public bool Strict { get; } = strict;

    private string? CurrentPower = null;

    public IScriptHandler? HandleInput(string input)
    {
        if (input == "") {
            CurrentPower = null;
            return this;
        }
        if (input.StartsWith('#')) return this;

        // "---" submits the orders and allows queries about the outcome
        if (input == "---") {
            Console.WriteLine("Submitting orders for adjudication");
            // TODO submit, validate, and adjudicate orders
            // TODO pass validation, adjudication, and prev/next World to next handler
            return new AdjudicationQueryScriptHandler(World, Strict);
        }

        // "===" submits the orders and moves immediately to taking the next set of orders
        // i.e. it's "---" twice
        if (input == "===") {
            Console.WriteLine("Submitting orders for adjudication");
            // TODO submit, validate, and adjudicate orders
            // TODO replace World with updated world and return a new handler
            Console.WriteLine("Ready for orders");
            return new GameScriptHandler(World, Strict);
        }

        // A block of orders for a single power beginning with "{name}:"
        if (World.Powers.FirstOrDefault(p => input.EqualsAnyCase($"{p}:"), null) is string power) {
            CurrentPower = power;
            return this;
        }

        if (TryParseOrder(input, out Order? order)) {
            Console.WriteLine($"Parsed order \"{input}\" but doing anything with it isn't implemented yet");
        } else if (Strict) {
            return null;
        }

        return this;
    }

    private bool TryParseOrder(string input, out Order? order) {
        order = null;
        OrderRegex re = new(World);
        Match match;
        if ((match = re.Hold.Match(input)).Success) {
            var hold = OrderRegex.ParseHold(match);
            string power = hold.power.Length > 0 ? hold.power : CurrentPower ?? hold.power;
            Unit unit = World.Units.First(unit
                => World.Map.GetLocation(unit.Location).ProvinceName == hold.province
                && unit.Season.Timeline == (hold.timeline.Length > 0 ? hold.timeline : "a")
                && unit.Season.Turn.ToString() == (hold.turn.Length > 0 ? hold.turn : "0"));
            order = new HoldOrder(power, unit);
            return true;
        } else if ((match = re.Move.Match(input)).Success) {
            var move = OrderRegex.ParseMove(match);
            Unit unit = World.Units.First(unit
                => World.Map.GetLocation(unit.Location).ProvinceName == move.province
                && unit.Season.Timeline == (move.timeline.Length > 0 ? move.timeline : "a")
                && unit.Season.Turn.ToString() == (move.turn.Length > 0 ? move.turn : "0"));
            order = new MoveOrder(move.power, unit, Season.First, "l");
            return true;
        }       

        Console.WriteLine($"Failed to parse \"{input}\"");
        return false;
    }
}