using System;
using System.Collections.Generic;
using UnityEngine;

namespace Jovian.EncounterSystem {
    [CreateAssetMenu(fileName = "EncounterTable", menuName = "Jovian/Encounter System/Encounter Table", order = 1)]
    public class EncounterTable : ScriptableObject {
        public string id;
        public List<Encounter> encounters;

        public IEncounter GetRandomEncounter() {
            if(encounters == null || encounters.Count == 0) {
                return null;
            }

            return encounters[UnityEngine.Random.Range(0, encounters.Count)];
        }

        public IEncounter GetRandomEncounter(Type type) {
            if(encounters == null || encounters.Count == 0) {
                return null;
            }

            var encountersOfType = encounters.FindAll(encounter => encounter.GetType() == type);
            if(encountersOfType.Count > 0) {
                return encountersOfType[UnityEngine.Random.Range(0, encountersOfType.Count)];
            }

            return null;
        }

        /// <summary>Random pick limited by a predicate. Used with <see cref="QuestProgress.IsGated"/> to exclude gated encounters.</summary>
        public IEncounter GetRandomEncounter(Predicate<IEncounter> filter) {
            if(encounters == null || encounters.Count == 0 || filter == null) {
                return GetRandomEncounter();
            }

            var pool = encounters.FindAll(filter);
            if(pool.Count == 0) {
                return null;
            }

            return pool[UnityEngine.Random.Range(0, pool.Count)];
        }

#if UNITY_EDITOR
        // Unity's inspector "+" duplicates the previous list element, including nested internalId
        // GUIDs. Regenerate any duplicates so every encounter carries a unique internalId.
        private void OnValidate() {
            if(encounters == null) {
                return;
            }

            var seen = new HashSet<string>();
            var changed = false;
            foreach(var encounter in encounters) {
                if(encounter?.EncounterDefinition == null) {
                    continue;
                }

                var id = encounter.EncounterDefinition.internalId;
                if(string.IsNullOrEmpty(id) || !seen.Add(id)) {
                    encounter.EncounterDefinition.internalId = Guid.NewGuid().ToString();
                    seen.Add(encounter.EncounterDefinition.internalId);
                    changed = true;
                }
            }

            if(changed) {
                UnityEditor.EditorUtility.SetDirty(this);
            }
        }
#endif
    }
}