using System;
using System.Collections.Generic;
using System.IO;
using NightclubArcadia.Skills;
using UnityEditor;
using UnityEditor.Callbacks;
using UnityEngine;

/// <summary>
/// Regenerates CandidateDefinition assets + CandidateDatabase from candidates.json.
///
/// The JSON is the source of truth; .asset files are build output and hand-edits are lost
/// on script reload by EnsureCandidateAssetsOnly.
/// </summary>
public static class CandidateSystemSetup
{
    const string CandidatesFolder = "Assets/Candidates";
    const string DefinitionsFolder = "Assets/Candidates/Definitions";
    const string JsonPath = "Assets/Candidates/candidates.json";
    const string DatabasePath = "Assets/Candidates/CandidateDatabase.asset";
    const string AutoSetupSessionKey = "NightclubArcadia.CandidateSystem.AutoSetupDone";

    [DidReloadScripts]
    static void AutoSetupAfterReload()
    {
        if (EditorApplication.isPlayingOrWillChangePlaymode)
        {
            return;
        }

        if (SessionState.GetBool(AutoSetupSessionKey, false))
        {
            return;
        }

        EditorApplication.delayCall += () =>
        {
            if (SessionState.GetBool(AutoSetupSessionKey, false))
            {
                return;
            }

            SessionState.SetBool(AutoSetupSessionKey, true);
            EnsureCandidateAssetsOnly();
        };
    }

    [MenuItem("Tools/Nightclub Arcadia/Set Up Candidate System")]
    public static void SetUpCandidateSystem()
    {
        EnsureCandidateAssetsOnly();
    }

    /// <summary>
    /// Creates/updates ScriptableObject assets without opening a scene.
    /// Safe to run on domain reload.
    /// </summary>
    public static void EnsureCandidateAssetsOnly()
    {
        if (!TryLoadRoster(out var roster))
        {
            return;
        }

        EnsureFolder("Assets", "Candidates");
        EnsureFolder("Assets/Candidates", "Definitions");

        var definitions = new List<CandidateDefinition>();
        var rosterIds = new HashSet<string>(StringComparer.Ordinal);
        foreach (var entry in roster)
        {
            rosterIds.Add(entry.id);
            definitions.Add(CreateOrUpdateDefinition(entry));
        }

        DeleteOrphanDefinitions(rosterIds);

        var database = AssetDatabase.LoadAssetAtPath<CandidateDatabase>(DatabasePath);
        if (database == null)
        {
            database = ScriptableObject.CreateInstance<CandidateDatabase>();
            AssetDatabase.CreateAsset(database, DatabasePath);
        }

        database.EditorSetCandidates(definitions);
        EditorUtility.SetDirty(database);
        AssetDatabase.SaveAssets();
        Debug.Log($"[CandidateSystemSetup] Candidate assets ready at {DatabasePath}.");
    }

    static bool TryLoadRoster(out CandidateEntry[] roster)
    {
        roster = null;
        var text = AssetDatabase.LoadAssetAtPath<TextAsset>(JsonPath);
        if (text == null)
        {
            // JSON may exist on disk before Unity has imported it as a TextAsset.
            if (!File.Exists(JsonPath))
            {
                Debug.LogError($"[CandidateSystemSetup] Missing registry at {JsonPath}.");
                return false;
            }

            text = new TextAsset(File.ReadAllText(JsonPath));
        }

        CandidateRoot root;
        try
        {
            root = JsonUtility.FromJson<CandidateRoot>(text.text);
        }
        catch (Exception ex)
        {
            Debug.LogError($"[CandidateSystemSetup] Failed to parse {JsonPath}: {ex.Message}");
            return false;
        }

        if (root?.candidates == null || root.candidates.Length == 0)
        {
            Debug.LogError($"[CandidateSystemSetup] {JsonPath} has no candidates.");
            return false;
        }

        foreach (var entry in root.candidates)
        {
            if (entry == null || string.IsNullOrEmpty(entry.id))
            {
                Debug.LogError($"[CandidateSystemSetup] {JsonPath} contains a candidate with empty id.");
                return false;
            }

            if (!Enum.TryParse<SkillAxis>(entry.intuitionAxis, ignoreCase: true, out _))
            {
                Debug.LogError(
                    $"[CandidateSystemSetup] Candidate '{entry.id}': invalid intuitionAxis '{entry.intuitionAxis}'.");
                return false;
            }

            if (entry.clues == null)
            {
                continue;
            }

            foreach (var clue in entry.clues)
            {
                if (clue == null || string.IsNullOrEmpty(clue.id))
                {
                    Debug.LogError($"[CandidateSystemSetup] Candidate '{entry.id}' has a clue with empty id.");
                    return false;
                }

                if (!Enum.TryParse<CandidateEvidenceType>(clue.type, ignoreCase: true, out _))
                {
                    Debug.LogError(
                        $"[CandidateSystemSetup] Clue '{clue.id}': invalid type '{clue.type}'.");
                    return false;
                }

                var status = string.IsNullOrEmpty(clue.status) ? "Planned" : clue.status;
                if (!Enum.TryParse<CandidateClueStatus>(status, ignoreCase: true, out _))
                {
                    Debug.LogError(
                        $"[CandidateSystemSetup] Clue '{clue.id}': invalid status '{clue.status}'.");
                    return false;
                }
            }
        }

        roster = root.candidates;
        return true;
    }

    static CandidateDefinition CreateOrUpdateDefinition(CandidateEntry entry)
    {
        var path = $"{DefinitionsFolder}/{entry.id}.asset";
        var asset = AssetDatabase.LoadAssetAtPath<CandidateDefinition>(path);
        if (asset == null)
        {
            asset = ScriptableObject.CreateInstance<CandidateDefinition>();
            AssetDatabase.CreateAsset(asset, path);
        }

        asset.EditorSet(entry);
        EditorUtility.SetDirty(asset);
        return asset;
    }

    static void DeleteOrphanDefinitions(HashSet<string> rosterIds)
    {
        if (!AssetDatabase.IsValidFolder(DefinitionsFolder))
        {
            return;
        }

        var guids = AssetDatabase.FindAssets("t:CandidateDefinition", new[] { DefinitionsFolder });
        foreach (var guid in guids)
        {
            var path = AssetDatabase.GUIDToAssetPath(guid);
            var fileName = Path.GetFileNameWithoutExtension(path);
            if (rosterIds.Contains(fileName))
            {
                continue;
            }

            Debug.Log($"[CandidateSystemSetup] Deleting orphan definition {path}");
            AssetDatabase.DeleteAsset(path);
        }
    }

    static void EnsureFolder(string parent, string child)
    {
        var path = $"{parent}/{child}";
        if (!AssetDatabase.IsValidFolder(path))
        {
            AssetDatabase.CreateFolder(parent, child);
        }
    }
}