using System;
using System.Collections.Generic;
using BlockOutReplica.Domain;
using UnityEngine;

namespace BlockOutReplica.Infrastructure
{
    public static class OriginalFlowRepository
    {
        private const string CatalogPath = "OriginalFlow/levelcatalog";
        private const string ContinuousPath = "OriginalFlow/ContinuousLevelsConfigModel";

        public static BlockOutFlowDefinition Load()
        {
            SeedList catalog = Read<SeedList>(CatalogPath);
            ContinuousConfig continuous = Read<ContinuousConfig>(ContinuousPath);

            List<string> result = new List<string>();
            HashSet<string> used = new HashSet<string>(StringComparer.Ordinal);
            // TutorialABTestLevelList contains alternative tutorial families, not
            // twelve consecutive levels. Default packaged sequence is LevelsConfig.
            foreach (var entry in OriginalLevelSettings.All)
                AddUnique(new[] { entry.seedId }, result, used);
            AddUnique(catalog.seeds, result, used);

            if (result.Count == 0)
                result.AddRange(OriginalLevelRepository.GetLevelIds());

            int tutorialCount = 4;
            int returnHome = continuous.IsEnabled ? Mathf.Max(1, continuous.Level) : 1;
            return new BlockOutFlowDefinition(result, tutorialCount, returnHome);
        }

        private static T Read<T>(string resourcePath) where T : new()
        {
            TextAsset asset = Resources.Load<TextAsset>(resourcePath);
            if (asset == null) return new T();
            T value = JsonUtility.FromJson<T>(asset.text);
            return value == null ? new T() : value;
        }

        private static void AddUnique(IEnumerable<string> source,
            List<string> target, HashSet<string> used)
        {
            if (source == null) return;
            foreach (string id in source)
                if (!string.IsNullOrWhiteSpace(id) && used.Add(id)) target.Add(id);
        }

        [Serializable] private sealed class SeedList { public string[] seeds; }
        [Serializable] private sealed class ContinuousConfig
        {
            public bool IsEnabled;
            public int Level;
        }
    }
}