using System;
using System.Collections.Generic;
using System.Linq;
using ProjectI.Combat;
using UnityEngine;

namespace ProjectI.Builds
{
    [Serializable]
    public sealed class LocalLoadoutRecord
    {
        public int Version=1;
        public BuildLoadout Build=BuildLoadout.Default;
        public int FirstWeapon=1,SecondWeapon=2;
    }

    public static class LocalLoadoutStore
    {
        private const string Key="ProjectI.LocalLoadout.v1";
        public static LocalLoadoutRecord LoadValidated(IReadOnlyDictionary<int,AbilityTuning> catalog,AbilityUnlockState unlocks)
            => ValidateSerialized(PlayerPrefs.GetString(Key,""),catalog,unlocks);

        public static LocalLoadoutRecord ValidateSerialized(string json,IReadOnlyDictionary<int,AbilityTuning> catalog,AbilityUnlockState unlocks)
        {
            if(catalog==null||unlocks==null)throw new ArgumentNullException();
            LocalLoadoutRecord record;
            try{record=JsonUtility.FromJson<LocalLoadoutRecord>(json);}catch{record=null;}
            if(record==null||record.Version!=1)record=new LocalLoadoutRecord();
            var used=new HashSet<int>();
            int Repair(int selected,AbilitySlot slot)
            {
                if(catalog.TryGetValue(selected,out var definition)&&definition.Slot==slot&&unlocks.IsUnlocked(selected)&&used.Add(selected))return selected;
                int id=catalog.Values.Where(x=>x.Slot==slot&&unlocks.IsUnlocked(x.Id)&&!used.Contains(x.Id)).OrderBy(x=>x.Id).Select(x=>x.Id).FirstOrDefault();
                if(id==0)throw new InvalidOperationException("The unlocked roster cannot fill all build slots.");used.Add(id);return id;
            }
            var b=record.Build;
            record.Build=new BuildLoadout(Repair(b.PassiveFirst,AbilitySlot.Passive),Repair(b.PassiveSecond,AbilitySlot.Passive),Repair(b.ActiveFirst,AbilitySlot.Active),Repair(b.ActiveSecond,AbilitySlot.Active),Repair(b.ActiveThird,AbilitySlot.Active),Repair(b.Ultimate,AbilitySlot.Ultimate),Repair(b.Melee,AbilitySlot.Melee));
            var weapons=WeaponRoster.Entries.Where(x=>x!=null).Select(x=>x.weaponId).Distinct().ToArray();
            if(weapons.Length<2)throw new InvalidOperationException("The weapon roster requires two distinct weapons.");
            if(!weapons.Contains(record.FirstWeapon))record.FirstWeapon=weapons[0];
            if(!weapons.Contains(record.SecondWeapon)||record.SecondWeapon==record.FirstWeapon)record.SecondWeapon=weapons.First(x=>x!=record.FirstWeapon);
            return record;
        }
        public static void Save(LocalLoadoutRecord record)
        {
            if(record==null||record.Version!=1)throw new ArgumentException("Unsupported local loadout record.",nameof(record));
            PlayerPrefs.SetString(Key,JsonUtility.ToJson(record));PlayerPrefs.Save();
        }
    }
}