using System;
using System.Collections.Generic;
using System.IO;
using System.IO.Compression;
using System.Linq;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Text.Json;
using System.Threading;
using System.Threading.Tasks;
using Gott.Endpoints;
using Gott.Models;
using Microsoft.AspNetCore.Http;

namespace Gott.Services;

public partial class AnthropicService
{
    /// <summary>
    /// Optionen für AddToolsToPayload – ersetzt die 12 bool-Parameter.
    /// </summary>
    public record ToolPayloadOptions
    {
        public string Workspace { get; init; }
        public string AgentId { get; init; }
        public bool UseMemory { get; init; }
        public string WebSearchVersion { get; init; }
        public string ToolChoice { get; init; }
        public int Iteration { get; init; }
        public bool AllowUserChoice { get; init; }
        public bool PlanMode { get; init; }
        public bool IncludeRemote { get; init; }
        public bool IncludeGitHubSearch { get; init; }
        public bool IncludeSerperSearch { get; init; }
    }

    private readonly IHttpClientFactory _httpFactory;
    private readonly ToolService _toolService;
    private readonly DatabaseService _db;
    private readonly MemoryService _memoryService;
    private readonly ServerSettingsService _settings;
    private readonly VectorSearchService _vectorSearch;
    private readonly EmbeddingBackgroundService _embeddingBg;
    private ChatService _chatService;
    private TelegramService _telegramService;
    private ClaudeCliService _cliService;

    public AnthropicService(IHttpClientFactory httpFactory, ToolService toolService, DatabaseService db, MemoryService memoryService = null, ServerSettingsService settings = null, VectorSearchService vectorSearch = null, EmbeddingBackgroundService embeddingBg = null)
    {
        _httpFactory = httpFactory;
        _toolService = toolService;
        _db = db;
        _memoryService = memoryService;
        _settings = settings;
        _vectorSearch = vectorSearch;
        _embeddingBg = embeddingBg;
    }

    public void SetCliService(ClaudeCliService cliService)
    {
        _cliService = cliService;
    }

    /// <summary>
    /// Prüft ob die Claude CLI verfügbar ist.
    /// </summary>
    public bool IsCliAvailable => _cliService?.IsAvailable ?? false;

    /// <summary>
    /// Wird nach der Konstruktion gesetzt um zirkuläre Abhängigkeit zu vermeiden
    /// (ChatService → AnthropicService → ChatService).
    /// </summary>
    public void SetChatService(ChatService chatService)
    {
        _chatService = chatService;
    }

    public void SetTelegramService(TelegramService telegramService)
    {
        _telegramService = telegramService;
    }

    private OpenAiService _openAiService;
    public void SetOpenAiService(OpenAiService openAiService)
    {
        _openAiService = openAiService;
    }

    /// <summary>
    /// Liest Usage-Header aus einer Anthropic-Response und aktualisiert die api_keys-Tabelle.
    /// Fire-and-forget – Fehler werden stillschweigend ignoriert.
    /// </summary>
    private void TryUpdateKeyMeta(HttpResponseMessage httpResp, string apiToken)
    {
        try
        {
            var meta = AnthropicKeyChecker.ExtractMetaFromHeaders(httpResp.Headers);
            if (meta == null || string.IsNullOrEmpty(apiToken)) return;
            _ = _db.UpdateApiKeyMetaByToken(apiToken, meta.Status, meta.Plan, meta.Usage7d, meta.Usage5h);
        }
        catch { /* silent */ }
    }

    // ── Shared Helpers ──

    // TruncateToolResult → SseHelper.cs
    internal static string TruncateToolResult(string result) => SseHelper.TruncateToolResult(result);

    /// <summary>
    /// Extrahiert den Text der letzten User-Message aus der Message-Liste.
    /// </summary>
    private static string ExtractLastUserText(List<object> messages)
    {
        for (int i = messages.Count - 1; i >= 0; i--)
        {
            var json = JsonSerializer.Serialize(messages[i]);
            var el = JsonSerializer.Deserialize<JsonElement>(json);
            if (!el.TryGetProperty("role", out var role) || role.GetString() != "user") continue;
            if (!el.TryGetProperty("content", out var content)) continue;

            if (content.ValueKind == JsonValueKind.String)
                return content.GetString();

            if (content.ValueKind == JsonValueKind.Array)
            {
                foreach (var block in content.EnumerateArray())
                {
                    var type = block.TryGetProperty("type", out var t) ? t.GetString() : "";
                    if (type == "text" && block.TryGetProperty("text", out var txt))
                        return txt.GetString();
                }
            }
            break;
        }
        return null;
    }

    /// <summary>Extrahiert die letzten N User-Texte für Query-Erweiterung.</summary>
    private static string ExtractRecentUserTexts(List<object> messages, int count = 3, int maxLength = 500)
    {
        var texts = new List<string>();
        for (int i = messages.Count - 1; i >= 0 && texts.Count < count; i--)
        {
            var json = JsonSerializer.Serialize(messages[i]);
            var el = JsonSerializer.Deserialize<JsonElement>(json);
            if (!el.TryGetProperty("role", out var role) || role.GetString() != "user") continue;
            if (!el.TryGetProperty("content", out var content)) continue;

            string text = null;
            if (content.ValueKind == JsonValueKind.String)
                text = content.GetString();
            else if (content.ValueKind == JsonValueKind.Array)
            {
                foreach (var block in content.EnumerateArray())
                {
                    var type = block.TryGetProperty("type", out var t) ? t.GetString() : "";
                    if (type == "text" && block.TryGetProperty("text", out var txt))
                    { text = txt.GetString(); break; }
                }
            }
            if (!string.IsNullOrWhiteSpace(text))
                texts.Add(text);
        }

        texts.Reverse(); // chronological order
        var combined = string.Join(" ", texts);
        return combined.Length > maxLength ? combined.Substring(0, maxLength) : combined;
    }

    /// <summary>
    /// Baut den AutoContext-String aus Embedding-Suche.
    /// Shared zwischen StreamChat und StreamChatViaCli.
    /// </summary>
    private async Task<string> BuildAutoContextAsync(List<object> messages, string chainId, string agentId)
    {
        if (_vectorSearch == null || messages.Count == 0) return null;

        // Query-Erweiterung: letzte 2-3 User-Messages statt nur die letzte
        var queryText = ExtractRecentUserTexts(messages, count: 3, maxLength: 500);
        if (string.IsNullOrWhiteSpace(queryText)) return null;

        var contextResults = await _vectorSearch.SearchAsync(queryText, agentId, topN: 5, minScore: 0.35f);
        // Note: threshold lowered from 0.45 to 0.35 because hybrid search is now more precise
        contextResults.RemoveAll(r => r.ChainId == chainId || (r.TextPreview?.Length ?? 0) < 20);

        var memoryResults = await _vectorSearch.SearchMemoryFilesAsync(queryText, agentId, topN: 3, minScore: 0.35f);

        if (contextResults.Count == 0 && memoryResults.Count == 0) return null;

        var ctxSb = new StringBuilder();
        ctxSb.AppendLine("\n<recalled_context>");
        ctxSb.AppendLine("Die folgende Information wurde automatisch abgerufen und könnte relevant sein:");
        foreach (var r in contextResults)
        {
            var date = DateTime.TryParse(r.CreatedAt, out var dt) ? dt.ToString("yyyy-MM-dd HH:mm") : r.CreatedAt;
            // Use FullText (up to 800 chars) if available, otherwise TextPreview
            var displayText = r.FullText ?? r.TextPreview ?? "";
            if (displayText.Length > 800) displayText = displayText.Substring(0, 800);
            ctxSb.AppendLine($"- [Gespräch, {r.Role}, {date}]: {displayText}");
        }
        foreach (var r in memoryResults)
        {
            var displayText = r.FullText ?? r.TextPreview ?? "";
            if (displayText.Length > 800) displayText = displayText.Substring(0, 800);
            ctxSb.AppendLine($"- [Memory, {r.FilePath}]: {displayText}");
        }
        ctxSb.AppendLine("</recalled_context>");
        return ctxSb.ToString();
    }

    /// <summary>
    /// Extrahiert Bild-Blöcke aus der letzten User-Message, speichert sie als Temp-Dateien
    /// und gibt Datei-Referenz-Hinweise zurück, die der CLI-Prompt vorangestellt werden.
    /// </summary>
    private static string ExtractLastUserImageRefs(List<object> messages, List<string> tempPaths)
    {
        for (int i = messages.Count - 1; i >= 0; i--)
        {
            var json = JsonSerializer.Serialize(messages[i]);
            var el = JsonSerializer.Deserialize<JsonElement>(json);

            if (!el.TryGetProperty("role", out var role) || role.GetString() != "user") continue;
            if (!el.TryGetProperty("content", out var content) || content.ValueKind != JsonValueKind.Array) continue;

            var refs = new List<string>();
            var tempDir = Path.Combine(Path.GetTempPath(), "gott-cli-images");
            Directory.CreateDirectory(tempDir);

            foreach (var block in content.EnumerateArray())
            {
                var blockType = block.TryGetProperty("type", out var bt) ? bt.GetString() ?? "" : "";
                if (blockType != "image" && blockType != "file") continue;

                var source = block.TryGetProperty("source", out var src) ? src : default;
                if (source.ValueKind == JsonValueKind.Undefined) continue;

                var sourceType = source.TryGetProperty("type", out var st) ? st.GetString() ?? "" : "";
                if (sourceType != "base64") continue;

                var data = source.TryGetProperty("data", out var d) ? d.GetString() ?? "" : "";
                var mediaType = source.TryGetProperty("media_type", out var mt) ? mt.GetString() ?? "" : "";

                var ext = mediaType switch
                {
                    "image/png" => ".png",
                    "image/jpeg" => ".jpg",
                    "image/gif" => ".gif",
                    "image/webp" => ".webp",
                    "application/pdf" => ".pdf",
                    _ => ".bin"
                };
                var fileName = $"{Guid.NewGuid():N}{ext}";
                var filePath = Path.Combine(tempDir, fileName);

                try
                {
                    File.WriteAllBytes(filePath, Convert.FromBase64String(data));
                    tempPaths.Add(filePath);

                    var label = blockType == "image" ? "Screenshot" : "Datei";
                    refs.Add($"[{label}: {filePath}]");
                }
                catch
                {
                    // Base64-Decode fehlgeschlagen → überspringen
                }
            }

            if (refs.Count > 0)
            {
                return string.Join(" ", refs) + "\n<hint>Lies die referenzierten Dateien mit dem Read-Tool um sie zu sehen.</hint>";
            }
            break;
        }
        return null;
    }

    /// <summary>
    /// Löscht temporäre Bilddateien die für den CLI-Aufruf erstellt wurden.
    /// </summary>
    private static void CleanupTempImages(List<string> paths)
    {
        if (paths == null || paths.Count == 0) return;
        foreach (var path in paths)
        {
            try { if (File.Exists(path)) File.Delete(path); } catch { }
        }
    }

    private void LogPayload(string json, string sessionId, string chainId, int iteration)
    {
        if (_settings == null || !_settings.GetBool("PayloadLogging", false)) return;
        try
        {
            var logsDir = Path.Combine(AppContext.BaseDirectory, "data", "logs");
            Directory.CreateDirectory(logsDir);
            var timestamp = DateTimeOffset.UtcNow.ToUnixTimeSeconds();
            var baseName = $"{timestamp}-{sessionId}-{chainId}-iter{iteration}-payload";

            if (_settings?.GetBool("PayloadLoggingGzip", false) ?? false)
            {
                var filePath = Path.Combine(logsDir, baseName + ".json.gz");
                using var fs = File.Create(filePath);
                using var gz = new GZipStream(fs, CompressionLevel.Fastest);
                using var writer = new StreamWriter(gz, Encoding.UTF8);
                writer.Write(json);
            }
            else
            {
                File.WriteAllText(Path.Combine(logsDir, baseName + ".json"), json);
            }
        }
        catch { /* Logging darf nie die App crashen */ }
    }

    private Task FinalizeChain(ChainRecord chain, TokenUsage usage, int iterations, string stopReason, System.Diagnostics.Stopwatch sw, string streamErrorInfo = null)
        => SseHelper.FinalizeChain(_db, chain, usage, iterations, stopReason, sw, streamErrorInfo);

    /// <summary>
    /// Fügt Tool-Definitionen und WebSearch zum Payload hinzu.
    /// </summary>
    private void AddToolsToPayload(Dictionary<string, object> payload, ToolPayloadOptions opts)
    {
        var hasWorkspace = !string.IsNullOrEmpty(opts.Workspace);
        var includeMemory = opts.UseMemory && _memoryService != null && !string.IsNullOrEmpty(opts.AgentId);
        var includeMemorySearch = _vectorSearch != null && _vectorSearch.GetEmbeddingCount() > 0;
        var includeSendToSession = _db != null && _chatService != null;
        var hasTools = hasWorkspace || includeMemory || opts.IncludeRemote || includeMemorySearch || includeSendToSession || opts.IncludeGitHubSearch || opts.IncludeSerperSearch;
        var hasWebSearch = !string.IsNullOrEmpty(opts.WebSearchVersion);

        if (!hasTools && !hasWebSearch) return;

        var tools = new List<object>();
        if (hasTools)
        {
            var allTools = _toolService.GetToolDefinitions(new ToolDefinitionOptions
            {
                IncludeFileTools = hasWorkspace, IncludeMemory = includeMemory,
                IncludeUserChoice = opts.AllowUserChoice, IncludeRemote = opts.IncludeRemote,
                IncludeMemorySearch = includeMemorySearch, IncludeSendToSession = includeSendToSession,
                IncludeGitHubSearch = opts.IncludeGitHubSearch, IncludeSerperSearch = opts.IncludeSerperSearch
            });
            if (opts.PlanMode)
                allTools = _toolService.FilterReadOnlyTools(allTools);
            tools.AddRange(allTools);
        }
        if (hasWebSearch)
        {
            tools.Add(new { type = opts.WebSearchVersion, name = "web_search", max_uses = 5 });
            // web_search_20260209: Code Execution wird von der API automatisch injected – NICHT manuell hinzufügen!
        }
        payload["tools"] = tools;
        var effectiveChoice = (!opts.PlanMode && opts.ToolChoice == "any" && opts.Iteration == 1) ? "any" : "auto";
        payload["tool_choice"] = new { type = effectiveChoice };
    }

    /// <summary>
    /// Entfernt Messages vom Anfang der Liste, ohne tool_use/tool_result-Paare zu trennen.
    /// Gibt die tatsächliche Anzahl entfernter Messages zurück.
    /// </summary>
    private static int TrimMessagesCleanly(List<object> messages, int targetRemoveCount)
    {
        if (targetRemoveCount <= 0 || targetRemoveCount >= messages.Count)
            return 0;

        int removeCount = targetRemoveCount;

        // Sicherstellen, dass wir nicht mitten in einem tool_use/tool_result-Paar abschneiden
        while (removeCount < messages.Count - 1)
        {
            var firstRemaining = messages[removeCount];
            var firstRemainingJson = JsonSerializer.Serialize(firstRemaining);

            // Wenn die erste verbleibende Message ein tool_result ist → vorherige auch behalten
            if (firstRemainingJson.Contains("\"tool_result\""))
            {
                removeCount--;
                if (removeCount <= 0) return 0;
                continue;
            }

            // Wenn die letzte entfernte Message ein assistant mit tool_use ist → tool_result auch entfernen
            var lastRemovedJson = JsonSerializer.Serialize(messages[removeCount - 1]);
            if (lastRemovedJson.Contains("\"tool_use\"") && lastRemovedJson.Contains("\"assistant\""))
            {
                removeCount++;
                continue;
            }

            break;
        }

        if (removeCount > 0 && removeCount < messages.Count)
        {
            messages.RemoveRange(0, removeCount);
            return removeCount;
        }
        return 0;
    }

    private HttpClient CreateClient(string apiToken)
    {
        var client = _httpFactory.CreateClient();
        client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", apiToken);
        client.DefaultRequestHeaders.Add("anthropic-version", "2023-06-01");
        client.DefaultRequestHeaders.Add("anthropic-beta", "claude-code-20250219,oauth-2025-04-20,code-execution-2025-08-25");
        client.DefaultRequestHeaders.Add("User-Agent", "claude-cli/2.1.2 (external, cli)");
        client.DefaultRequestHeaders.Add("x-app", "cli");
        client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
        client.DefaultRequestHeaders.Add("anthropic-dangerous-direct-browser-access", "true");
        return client;
    }

    // WriteSseEvent, TryWriteSse, TokenUsage, ToolResult → SseHelper.cs
}