using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

using UnityEditor.Localization;
using UnityEngine;
using UnityEngine.Localization.Tables;

namespace Crowdin.Plugin.Operations
{
    using Helpers;
    using Helpers.FileHelpers;
    using Helpers.PluginLocalization;
    using Helpers.UnityLocalization;
    using Models;
    using Models.Settings;
    using Server_API;
    using Server_API.Helpers;
    using Server_API.Serializable;
    using Server_API.Serializable.Translations;
    using Server_API.Services;

    /// Pushes translations for existing strings to Crowdin. String-based projects re-upload the
    /// whole CSV; file-based projects either upload per-language translations against an existing
    /// source file, or - if the source file does not exist on Crowdin yet - create it with
    /// translations included in one request.
    public static class PushStringTranslations
    {
        private const int MaxConcurrentUploads = 10;

        public static Task<PushTranslationsResult> RunAsync(
            PushTranslationsOptions options,
            IProgress<OperationProgress> progress,
            CancellationToken cancellationToken)
        {
            progress.Report(new OperationProgress(LocalizationHelper.GetLocalStringByKey(LocalKeys.start_parsing_str_transl)));

            return SettingsHelper.GetProjectType() is ProjectType.StringBased
                ? PushStringBasedAsync(options, progress, cancellationToken)
                : PushFileBasedAsync(options, progress, cancellationToken);
        }

        private static async Task<PushTranslationsResult> PushStringBasedAsync(
            PushTranslationsOptions options,
            IProgress<OperationProgress> progress,
            CancellationToken cancellationToken)
        {
            var perLocaleTotal = new Dictionary<string, int>();
            int totalSent = 0;

            foreach (string tableName in options.Tables)
            {
                TranslationsHelper.RefreshAllStringsTranslation();

                StringTableCollection tableCollection = LocalizationEditorSettings.GetStringTableCollection(tableName);

                progress.Report(new OperationProgress(string.Empty));
                progress.Report(new OperationProgress(
                    LocalizationHelper.GetLocalStringByKey(LocalKeys.send_translations_str, tableName)));

                var perLocaleTable = new Dictionary<string, int>();
                foreach (LocalizationTableCollection.Row<StringTableEntry> row in tableCollection.GetRowEnumerator())
                {
                    string context = tableCollection.GetSharedEntryComments(row.KeyEntry.Id);

                    if (!ExportDataHelper.UpdateTranslationFromStringsTableRow(
                            row, tableName, context, out IReadOnlyList<string> localesWithTranslation))
                    {
                        Debug.LogErrorFormat(
                            "Failed to update translation from Row ID = {0} & Table Name = {1}",
                            row.KeyEntry.Id,
                            tableName);
                        continue;
                    }

                    foreach (string locale in localesWithTranslation)
                    {
                        perLocaleTable[locale] = perLocaleTable.GetValueOrDefault(locale) + 1;
                    }
                }

                bool uploaded = await StringBasedProjectsHelper.UploadStringBasedProject(
                    new StringBasedProjectsHelper.UploadProjectCommand
                    {
                        TableName = tableName,
                        SelectedBranchId = options.BranchId,
                        UpdateStrings = options.UpdateStrings,
                        CleanupMode = options.CleanupMode,
                        UpdateOption = null,
                        IncludeTranslations = true
                    },
                    progress,
                    cancellationToken);

                if (!uploaded)
                {
                    continue;
                }

                foreach ((string locale, int count) in perLocaleTable)
                {
                    progress.Report(new OperationProgress(LocalizationHelper.GetLocalStringByKey(
                        LocalKeys.finish_upload_transl_table, locale, count.ToString())));

                    perLocaleTotal[locale] = perLocaleTotal.GetValueOrDefault(locale) + count;
                    totalSent += count;
                }
            }

            return new PushTranslationsResult(totalSent, perLocaleTotal);
        }

        private static async Task<PushTranslationsResult> PushFileBasedAsync(
            PushTranslationsOptions options,
            IProgress<OperationProgress> progress,
            CancellationToken cancellationToken)
        {
            int rootDirId = await DirectoriesHelper.EnsureRootDirectoryAsync(cancellationToken);

            var sourceFilesService = new SourceFilesApiService();
            var storageService = new StorageApiService();
            var translationsService = new TranslationsApiService();

            var perLocaleTotal = new Dictionary<string, int>();
            int totalSent = 0;

            foreach (string tableName in options.Tables)
            {
                TranslationsHelper.RefreshAllStringsTranslation();

                StringTableCollection tableCollection = LocalizationEditorSettings.GetStringTableCollection(tableName);

                progress.Report(new OperationProgress(string.Empty));
                progress.Report(new OperationProgress(
                    LocalizationHelper.GetLocalStringByKey(LocalKeys.send_translations_str, tableName)));

                var perLocaleTable = new Dictionary<string, int>();
                foreach (LocalizationTableCollection.Row<StringTableEntry> row in tableCollection.GetRowEnumerator())
                {
                    string context = tableCollection.GetSharedEntryComments(row.KeyEntry.Id);

                    ExportDataHelper.UpdateTranslationFromStringsTableRow(
                        row, tableName, context, out IReadOnlyList<string> localesWithTranslation);

                    foreach (string locale in localesWithTranslation)
                    {
                        perLocaleTable[locale] = perLocaleTable.GetValueOrDefault(locale) + 1;
                    }
                }

                string fileName = $"{tableName}.csv";
                string filepath = $"{FolderHelper.resourcesDirectory}/{fileName}";
                CreateFileHelper.SaveTranslationsToFile(filepath, tableName, withTranslations: true);

                var failedLocales = new HashSet<string>();

                try
                {
                    List<FileData> existingFiles = await sourceFilesService.ListSourceFiles(rootDirId, cancellationToken);
                    FileData existing = existingFiles.FirstOrDefault(data => data.name == fileName);

                    if (existing is null)
                    {
                        // The source file was never pushed - create it with translations included.
                        await StorageHelper.UploadSourceFileAsync(
                            fileName, fileName, filepath, rootDirId, includeTranslationsInFile: true, cancellationToken);
                    }
                    else
                    {
                        StorageData storage =
                            await storageService.CreateStorage(fileName, filepath, cancellationToken);

                        List<LanguageItem> languages = SettingsHelper.GetLanguageScheme();

                        for (var offset = 0; offset < languages.Count; offset += MaxConcurrentUploads)
                        {
                            IEnumerable<LanguageItem> batch = languages.Skip(offset).Take(MaxConcurrentUploads);

                            await Task.WhenAll(batch.Select(async language =>
                            {
                                try
                                {
                                    await translationsService.UploadTranslation(
                                        new UpdateTranslationQueryData(existing.id, storage.id, options.AutoApprove),
                                        language.langType,
                                        cancellationToken);
                                }
                                catch (CrowdinApiException ex)
                                {
                                    failedLocales.Add(language.langType);
                                    Debug.LogException(ex);
                                    progress.Report(new OperationProgress(LocalizationHelper.GetLocalStringByException(ex)));
                                }
                            }));
                        }
                    }
                }
                catch (CrowdinApiException ex)
                {
                    // A table-level API error (e.g. a name conflict when creating the source file)
                    // must not abort the remaining tables, same as PushStrings does.
                    Debug.LogException(ex);
                    progress.Report(new OperationProgress(LocalizationHelper.GetLocalStringByException(ex)));
                    continue;
                }
                finally
                {
                    RemoveFileHelper.RemoveFile(filepath);
                }

                foreach ((string locale, int count) in perLocaleTable)
                {
                    if (failedLocales.Contains(locale))
                    {
                        continue;
                    }

                    progress.Report(new OperationProgress(LocalizationHelper.GetLocalStringByKey(
                        LocalKeys.finish_upload_transl_table, locale, count.ToString())));

                    perLocaleTotal[locale] = perLocaleTotal.GetValueOrDefault(locale) + count;
                    totalSent += count;
                }
            }

            return new PushTranslationsResult(totalSent, perLocaleTotal);
        }
    }
}