using System;
using System.Collections.Generic;
using System.Text;
using AlicizaX.Localization.Runtime;
using UnityEditor;
using UnityEngine;

namespace AlicizaX.Localization.Editor
{
    [Serializable]
    public sealed class LocalizationAiWriteRequest
    {
        public string TableAssetPath;
        public string SectionName = "AI";
        public string Key;
        public bool AllowUpdate = true;
        public bool AutoCreateSection = true;
        public bool AutoCreateLanguageAsset = true;
        public bool FillMissingLanguagesWithEmpty = true;
        public bool SaveAssets = true;
        public bool HotReloadWhenPlaying = true;
        public List<LocalizationAiTranslation> Translations = new();
    }

    [Serializable]
    public sealed class LocalizationAiTranslation
    {
        public string Language;
        public string Text;
    }

    [Serializable]
    public sealed class LocalizationAiWriteResult
    {
        public bool Success;
        public string TableAssetPath;
        public string SectionName;
        public string Key;
        public string RuntimeKey;
        public bool CreatedSection;
        public bool CreatedEntry;
        public bool HotReloaded;
        public List<string> UpdatedLanguages = new();
        public List<string> Warnings = new();
        public string Message;
    }

    public static class LocalizationAiWriteTool
    {
        private const string DefaultSectionName = "AI";
        private const string LastSelectedTableKey = "LastSelectedGameLocaizationTable";

        public static LocalizationAiWriteResult Execute(LocalizationAiWriteRequest request)
        {
            LocalizationAiWriteResult result = new();
            if (request == null)
            {
                result.Message = "Request is null.";
                return result;
            }

            string tablePath = request.TableAssetPath;
            if (string.IsNullOrWhiteSpace(tablePath))
            {
                tablePath = EditorPrefs.GetString(LastSelectedTableKey, string.Empty);
            }

            if (string.IsNullOrWhiteSpace(tablePath))
            {
                result.Message = "TableAssetPath is empty.";
                return result;
            }

            GameLocaizationTable table = AssetDatabase.LoadAssetAtPath<GameLocaizationTable>(tablePath);
            if (table == null)
            {
                result.Message = $"Can not load GameLocaizationTable from path: {tablePath}";
                result.TableAssetPath = tablePath;
                return result;
            }

            result.TableAssetPath = tablePath;

            string sectionName = request.SectionName;
            string itemKey = request.Key;
            ParseAndNormalizeKey(ref sectionName, ref itemKey);

            if (string.IsNullOrEmpty(sectionName))
            {
                sectionName = DefaultSectionName;
            }

            if (string.IsNullOrEmpty(itemKey))
            {
                result.Message = "Key is empty after normalization.";
                return result;
            }

            if (table.TableSheet == null)
            {
                table.TableSheet = new List<GameLocaizationTable.TableData>();
            }

            if (table.Languages == null)
            {
                table.Languages = new List<LocalizationLanguage>();
            }

            int sectionIndex = FindSectionIndex(table, sectionName);
            if (sectionIndex < 0)
            {
                if (!request.AutoCreateSection)
                {
                    result.Message = $"Section '{sectionName}' does not exist.";
                    return result;
                }

                GameLocaizationTable.TableData newSection = new(sectionName, GenerateUniqueSectionId(table));
                table.TableSheet.Add(newSection);
                sectionIndex = table.TableSheet.Count - 1;
                result.CreatedSection = true;
            }

            GameLocaizationTable.TableData section = table.TableSheet[sectionIndex];
            if (section.SectionSheet == null)
            {
                section.SectionSheet = new List<GameLocaizationTable.SheetItem>();
            }

            int entryIndex = FindEntryIndex(section, itemKey);
            bool createdEntry = false;
            if (entryIndex < 0)
            {
                GameLocaizationTable.SheetItem newItem = new(itemKey, GenerateUniqueEntryId(table), true);
                section.SectionSheet.Add(newItem);
                entryIndex = section.SectionSheet.Count - 1;
                createdEntry = true;
                result.CreatedEntry = true;
            }
            else if (!request.AllowUpdate)
            {
                result.Message = $"Key '{itemKey}' already exists in section '{sectionName}'.";
                return result;
            }

            GameLocaizationTable.SheetItem entry = section.SectionSheet[entryIndex];
            string runtimeKey = BuildRuntimeKey(section.SectionName, entry.Key);

            Dictionary<string, string> translationMap = BuildTranslationMap(request.Translations, result.Warnings);
            EnsureEntryExistsForAllLanguages(table, section, entry, runtimeKey, translationMap, request, result);

            table.TableSheet[sectionIndex] = section;

            table.InvalidateLanguageLookup();
            EditorUtility.SetDirty(table);
            if (request.SaveAssets)
            {
                AssetDatabase.SaveAssets();
                AssetDatabase.Refresh();
            }

            if (request.HotReloadWhenPlaying &&
                Application.isPlaying &&
                AppServices.TryGet<ILocalizationService>(out var localizationService))
            {
                localizationService.ReloadLocalizationConfig(table);
                result.HotReloaded = true;
            }

            result.Success = true;
            result.SectionName = section.SectionName;
            result.Key = entry.Key;
            result.RuntimeKey = runtimeKey;
            result.Message = createdEntry
                ? $"Added localization entry '{runtimeKey}'."
                : $"Updated localization entry '{runtimeKey}'.";
            return result;
        }

        public static string ExecuteJson(string json)
        {
            LocalizationAiWriteRequest request = Utility.Json.ToObject<LocalizationAiWriteRequest>(json);
            LocalizationAiWriteResult result = Execute(request);
            return Utility.Json.ToJson(result);
        }

        private static void EnsureEntryExistsForAllLanguages(
            GameLocaizationTable table,
            GameLocaizationTable.TableData section,
            GameLocaizationTable.SheetItem entry,
            string runtimeKey,
            Dictionary<string, string> translationMap,
            LocalizationAiWriteRequest request,
            LocalizationAiWriteResult result)
        {
            for (int i = 0; i < table.Languages.Count; i++)
            {
                LocalizationLanguage language = table.Languages[i];
                if (language == null)
                {
                    continue;
                }

                UpsertLanguageEntry(
                    language,
                    section.Id,
                    entry.Id,
                    runtimeKey,
                    translationMap.TryGetValue(language.LanguageName, out string text) ? text : string.Empty,
                    translationMap.ContainsKey(language.LanguageName) || request.FillMissingLanguagesWithEmpty);

                EditorUtility.SetDirty(language);
                result.UpdatedLanguages.Add(language.LanguageName);
            }

            foreach (KeyValuePair<string, string> pair in translationMap)
            {
                if (HasLanguage(table, pair.Key))
                {
                    continue;
                }

                if (!request.AutoCreateLanguageAsset)
                {
                    result.Warnings.Add($"Language asset '{pair.Key}' does not exist in table '{table.name}'.");
                    continue;
                }

                LocalizationLanguage language = CreateLanguageAsset(table, pair.Key);
                UpsertLanguageEntry(language, section.Id, entry.Id, runtimeKey, pair.Value, true);
                EditorUtility.SetDirty(language);
                result.UpdatedLanguages.Add(language.LanguageName);
            }
        }

        private static void UpsertLanguageEntry(
            LocalizationLanguage language,
            int sectionId,
            int entryId,
            string runtimeKey,
            string value,
            bool shouldWrite)
        {
            if (language.Strings == null)
            {
                language.Strings = new List<LocalizationLanguage.LocalizationString>();
            }

            int index = FindLanguageStringIndex(language, sectionId, entryId);
            if (index >= 0)
            {
                LocalizationLanguage.LocalizationString item = language.Strings[index];
                item.Key = runtimeKey;
                if (shouldWrite)
                {
                    item.Value = value ?? string.Empty;
                }

                language.Strings[index] = item;
                return;
            }

            if (!shouldWrite)
            {
                return;
            }

            language.Strings.Add(new LocalizationLanguage.LocalizationString
            {
                SectionId = sectionId,
                EntryId = entryId,
                Key = runtimeKey,
                Value = value ?? string.Empty
            });
        }

        private static LocalizationLanguage CreateLanguageAsset(GameLocaizationTable table, string languageName)
        {
            LocalizationLanguage language = ScriptableObject.CreateInstance<LocalizationLanguage>();
            language.name = languageName;
            language.LanguageName = languageName;
            language.Strings = new List<LocalizationLanguage.LocalizationString>();
            AssetDatabase.AddObjectToAsset(language, table);
            table.Languages.Add(language);
            table.InvalidateLanguageLookup();
            EditorUtility.SetDirty(table);
            return language;
        }

        private static Dictionary<string, string> BuildTranslationMap(
            List<LocalizationAiTranslation> translations,
            List<string> warnings)
        {
            Dictionary<string, string> map = new(StringComparer.Ordinal);
            if (translations == null)
            {
                return map;
            }

            for (int i = 0; i < translations.Count; i++)
            {
                LocalizationAiTranslation translation = translations[i];
                if (translation == null || string.IsNullOrWhiteSpace(translation.Language))
                {
                    continue;
                }

                string normalizedLanguage = NormalizePart(translation.Language);
                if (string.IsNullOrEmpty(normalizedLanguage))
                {
                    continue;
                }

                if (map.ContainsKey(normalizedLanguage))
                {
                    warnings.Add($"Duplicate language '{normalizedLanguage}' found. Last value wins.");
                }

                map[normalizedLanguage] = translation.Text ?? string.Empty;
            }

            return map;
        }

        private static bool HasLanguage(GameLocaizationTable table, string languageName)
        {
            for (int i = 0; i < table.Languages.Count; i++)
            {
                LocalizationLanguage language = table.Languages[i];
                if (language != null && string.Equals(language.LanguageName, languageName, StringComparison.Ordinal))
                {
                    return true;
                }
            }

            return false;
        }

        private static int FindSectionIndex(GameLocaizationTable table, string sectionName)
        {
            for (int i = 0; i < table.TableSheet.Count; i++)
            {
                if (string.Equals(table.TableSheet[i].SectionName, sectionName, StringComparison.Ordinal))
                {
                    return i;
                }
            }

            return -1;
        }

        private static int FindEntryIndex(GameLocaizationTable.TableData section, string itemKey)
        {
            for (int i = 0; i < section.SectionSheet.Count; i++)
            {
                if (string.Equals(section.SectionSheet[i].Key, itemKey, StringComparison.Ordinal))
                {
                    return i;
                }
            }

            return -1;
        }

        private static int FindLanguageStringIndex(LocalizationLanguage language, int sectionId, int entryId)
        {
            for (int i = 0; i < language.Strings.Count; i++)
            {
                LocalizationLanguage.LocalizationString item = language.Strings[i];
                if (item.SectionId == sectionId && item.EntryId == entryId)
                {
                    return i;
                }
            }

            return -1;
        }

        private static int GenerateUniqueSectionId(GameLocaizationTable table)
        {
            return GenerateUniqueId(table, true);
        }

        private static int GenerateUniqueEntryId(GameLocaizationTable table)
        {
            return GenerateUniqueId(table, false);
        }

        private static int GenerateUniqueId(GameLocaizationTable table, bool checkSectionIds)
        {
            int candidate = Mathf.Abs(Guid.NewGuid().GetHashCode());
            while (candidate == 0 || ContainsId(table, candidate, checkSectionIds))
            {
                candidate = Mathf.Abs(Guid.NewGuid().GetHashCode());
            }

            return candidate;
        }

        private static bool ContainsId(GameLocaizationTable table, int id, bool checkSectionIds)
        {
            for (int i = 0; i < table.TableSheet.Count; i++)
            {
                GameLocaizationTable.TableData section = table.TableSheet[i];
                if (checkSectionIds && section.Id == id)
                {
                    return true;
                }

                if (section.SectionSheet == null)
                {
                    continue;
                }

                for (int j = 0; j < section.SectionSheet.Count; j++)
                {
                    if (!checkSectionIds && section.SectionSheet[j].Id == id)
                    {
                        return true;
                    }
                }
            }

            return false;
        }

        private static string BuildRuntimeKey(string sectionName, string itemKey)
        {
            return string.Concat(sectionName, ".", itemKey);
        }

        private static void ParseAndNormalizeKey(ref string sectionName, ref string itemKey)
        {
            if (!string.IsNullOrWhiteSpace(itemKey))
            {
                int separatorIndex = itemKey.IndexOf('.');
                if (separatorIndex > 0 && separatorIndex < itemKey.Length - 1)
                {
                    sectionName = itemKey.Substring(0, separatorIndex);
                    itemKey = itemKey.Substring(separatorIndex + 1);
                }
            }

            sectionName = NormalizePart(sectionName);
            itemKey = NormalizePart(itemKey);
        }

        private static string NormalizePart(string value)
        {
            if (string.IsNullOrWhiteSpace(value))
            {
                return string.Empty;
            }

            StringBuilder builder = new(value.Length);
            for (int i = 0; i < value.Length; i++)
            {
                char current = value[i];
                if (char.IsLetterOrDigit(current) || current == '_')
                {
                    builder.Append(current);
                    continue;
                }

                if (char.IsWhiteSpace(current) || current == '-' || current == '/')
                {
                    builder.Append('_');
                }
            }

            while (builder.Length > 0 && builder[0] == '_')
            {
                builder.Remove(0, 1);
            }

            while (builder.Length > 0 && builder[builder.Length - 1] == '_')
            {
                builder.Remove(builder.Length - 1, 1);
            }

            return builder.ToString();
        }
    }
}