using System;
using static PKHeX.Core.StaticCorrelation8bRequirement;

namespace PKHeX.Core
{
    /// <summary>
    /// Generation 7 Static Encounter
    /// </summary>
    /// <inheritdoc cref="EncounterStatic"/>
    public sealed record EncounterStatic8b : EncounterStatic, IStaticCorrelation8b
    {
        public override int Generation => 8;

        public bool Roaming { get; init; }
        public override bool EggEncounter => EggLocation != Locations.Default8bNone;

        public EncounterStatic8b(GameVersion game) : base(game) => EggLocation = Locations.Default8bNone;

        protected override bool IsMatchLocation(PKM pkm)
        {
            if (pkm is PK8)
                return Locations.IsValidMetBDSP(pkm.Met_Location, pkm.Version);
            if (!Roaming)
                return base.IsMatchLocation(pkm);
            return IsRoamingLocation(pkm);
        }

        private static bool IsRoamingLocation(PKM pkm)
        {
            var location = pkm.Met_Location;
            foreach (var value in Roaming_MetLocation_BDSP)
            {
                if (value == location)
                    return true;
            }
            return false;
        }

        public StaticCorrelation8bRequirement GetRequirement(PKM pk) => Roaming
            ? MustHave
            : MustNotHave;

        public bool IsStaticCorrelationCorrect(PKM pk)
        {
            return Roaming8bRNG.ValidateRoamingEncounter(pk, Shiny == Shiny.Random ? Shiny.FixedValue : Shiny, FlawlessIVCount);
        }

        protected override bool IsMatchEggLocation(PKM pkm)
        {
            if (pkm is not PB8)
            {
                if (!EggEncounter)
                    return pkm.Egg_Location == 0;

                if (pkm is PK8)
                {
                    if (EggLocation > 60000 && pkm.Egg_Location == Locations.HOME_SWSHBDSPEgg)
                        return true;
                    // >60000 can be reset to Link Trade (30001), then altered differently.
                    return Locations.IsValidMetBDSP(pkm.Egg_Location, pkm.Version);
                }

                // Hatched
                return pkm.Egg_Location == EggLocation || pkm.Egg_Location == Locations.LinkTrade6NPC;
            }

            var eggloc = pkm.Egg_Location;
            if (!EggEncounter)
                return eggloc == EggLocation;

            if (!pkm.IsEgg) // hatched
                return eggloc == EggLocation || eggloc == Locations.LinkTrade6NPC;

            // Unhatched:
            if (eggloc != EggLocation)
                return false;
            if (pkm.Met_Location is not (Locations.Default8bNone or Locations.LinkTrade6NPC))
                return false;
            return true;
        }

        protected override void ApplyDetails(ITrainerInfo sav, EncounterCriteria criteria, PKM pk)
        {
            pk.Met_Location = pk.Egg_Location = Locations.Default8bNone;
            base.ApplyDetails(sav, criteria, pk);
            var req = GetRequirement(pk);
            if (req == MustHave) // Roamers
            {
                var shiny = Shiny == Shiny.Random ? Shiny.FixedValue : Shiny;
                Roaming8bRNG.ApplyDetails(pk, criteria, shiny, FlawlessIVCount);
            }
            else
            {
                var shiny = Shiny == Shiny.Never ? Shiny.Never : Shiny.Random;
                Wild8bRNG.ApplyDetails(pk, criteria, shiny, FlawlessIVCount, Ability);
            }
        }

        protected override void SetMetData(PKM pk, int level, DateTime today)
        {
            pk.Met_Level = level;
            pk.Met_Location = !Roaming ? Location : Roaming_MetLocation_BDSP[0];
            pk.MetDate = today;
        }

        // defined by mvpoke in encounter data
        private static readonly ushort[] Roaming_MetLocation_BDSP =
        {
            197, 201, 354, 355, 356, 357, 358, 359, 361, 362, 364, 365, 367, 373, 375, 377,
            378, 379, 383, 385, 392, 394, 395, 397, 400, 403, 404, 407,
            485,
        };
    }

    public interface IStaticCorrelation8b
    {
        StaticCorrelation8bRequirement GetRequirement(PKM pk);
        bool IsStaticCorrelationCorrect(PKM pk);
    }

    public enum StaticCorrelation8bRequirement
    {
        CanBeEither,
        MustHave,
        MustNotHave,
    }
}