using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Text;
using System.Text.Json;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;

namespace Gott.Services;

/// <summary>
/// Service für die Kommunikation mit der Claude Code CLI.
/// Verwendet die CLI als Backend für OAuth-basierte Chats (kein API-Key nötig).
/// </summary>
public class ClaudeCliService
{
    private readonly ILogger<ClaudeCliService> _logger;
    private readonly string _cliPath;
    private readonly bool _isAvailable;

    public ClaudeCliService(ILogger<ClaudeCliService> logger)
    {
        _logger = logger;
        _cliPath = FindCliPath();
        _isAvailable = !string.IsNullOrEmpty(_cliPath) && File.Exists(_cliPath);

        if (_isAvailable)
            _logger.LogInformation("Claude CLI gefunden: {Path}", _cliPath);
        else
            _logger.LogWarning("Claude CLI nicht gefunden. CLI-basierte Chats sind nicht verfügbar.");
    }

    public bool IsAvailable => _isAvailable;
    public string CliPath => _cliPath;

    private ProcessStartInfo CreateCliStartInfo(List<string> args, bool redirectInput = false)
    {
        var psi = new ProcessStartInfo
        {
            FileName = _cliPath,
            RedirectStandardInput = redirectInput,
            RedirectStandardOutput = true,
            RedirectStandardError = true,
            UseShellExecute = false,
            CreateNoWindow = true,
            StandardOutputEncoding = Encoding.UTF8,
            StandardErrorEncoding = Encoding.UTF8
        };

        foreach (var arg in args)
            psi.ArgumentList.Add(arg);

        return psi;
    }

    private static string FindCliPath()
    {
        // 1. Expliziter Pfad über Umgebungsvariable (höchste Priorität)
        var envPath = Environment.GetEnvironmentVariable("CLAUDE_CLI_PATH");
        if (!string.IsNullOrEmpty(envPath) && File.Exists(envPath))
            return envPath;

        // 2. Bekannte Installationspfade
        var possiblePaths = new[]
        {
            // Windows: standalone install
            Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), "Programs", "claude-code", "claude.exe"),
            // Windows/Linux: local bin (funktioniert nur wenn Dienst unter dem richtigen User läuft)
            Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), ".local", "bin", "claude.exe"),
            Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), ".local", "bin", "claude"),
            // Linux: system paths
            "/usr/local/bin/claude",
            "/usr/bin/claude"
        };

        foreach (var path in possiblePaths)
        {
            if (File.Exists(path))
                return path;
        }

        // 3. PATH-Suche
        try
        {
            var pathEnv = Environment.GetEnvironmentVariable("PATH") ?? "";
            foreach (var dir in pathEnv.Split(Path.PathSeparator))
            {
                var exePath = Path.Combine(dir, "claude.exe");
                if (File.Exists(exePath)) return exePath;

                exePath = Path.Combine(dir, "claude");
                if (File.Exists(exePath)) return exePath;
            }
        }
        catch { }

        return null;
    }

    /// <summary>
    /// Streaming-Chat über die Claude CLI mit Event-basiertem Callback.
    /// Unterstützt Text-Streaming und Tool-Use Events.
    /// </summary>
    public async Task<CliChatResult> ChatStreamingAsync(
        string prompt,
        Func<CliStreamEvent, Task> onEvent,
        string modelId = null,
        string systemPrompt = null,
        string workspace = null,
        bool hasWorkspace = false,
        bool planMode = false,
        bool webSearch = false,
        string mcpConfigPath = null,
        bool hasUnityMcp = false,
        CancellationToken cancellationToken = default)
    {
        if (!_isAvailable)
            return new CliChatResult { Success = false, Error = "Claude CLI nicht verfügbar" };

        var args = new List<string>
        {
            "-p",
            "--verbose",
            "--output-format", "stream-json",
            "--include-partial-messages",
            "--no-session-persistence",
            "--permission-mode", "acceptEdits",
            "--disallowed-tools", "AskUserQuestion"
        };

        // Tools konfigurieren
        var tools = new List<string>();
        if (hasWorkspace && planMode)
        {
            // Plan-Modus: nur read-only Tools
            tools.AddRange(new[] { "Read", "Glob", "Grep" });
        }
        else if (hasWorkspace)
        {
            // Normaler Modus mit Workspace: alle File-Tools
            tools.AddRange(new[] { "Bash(*)", "Read", "Write", "Edit", "Glob", "Grep" });
        }
        else
        {
            // Kein Workspace: Read für Temp-Dateien (z.B. gesendete Bilder)
            tools.Add("Read");
        }
        if (webSearch) { tools.Add("WebFetch"); tools.Add("WebSearch"); }
        // MCP-Tools erlauben (wenn MCP-Config vorhanden)
        if (!string.IsNullOrEmpty(mcpConfigPath))
        {
            tools.Add("mcp__gott-remote__remote_execute");
            tools.Add("mcp__gott-remote__ask_user_choice");
            tools.Add("mcp__gott-remote__memory_read");
            tools.Add("mcp__gott-remote__memory_write");
            tools.Add("mcp__gott-remote__memory_list");
        }
        // Unity MCP Tools erlauben (alle Tools vom unity MCP-Server)
        if (hasUnityMcp)
        {
            tools.Add("mcp__unity__*");
        }
        args.Add("--allowed-tools");
        args.Add(tools.Count > 0 ? string.Join(" ", tools) : "\"\"");

        if (!string.IsNullOrEmpty(workspace))
        {
            args.Add("--add-dir");
            args.Add(workspace);
        }

        // Temp-Ordner immer zugänglich machen (für gesendete Bilder etc.)
        var tempImageDir = Path.Combine(Path.GetTempPath(), "gott-cli-images");
        if (Directory.Exists(tempImageDir))
        {
            args.Add("--add-dir");
            args.Add(tempImageDir);
        }

        if (!string.IsNullOrEmpty(modelId))
        {
            args.Add("--model");
            args.Add(modelId);
        }

        if (!string.IsNullOrEmpty(systemPrompt))
        {
            args.Add("--system-prompt");
            args.Add(systemPrompt);
        }

        if (!string.IsNullOrEmpty(mcpConfigPath))
        {
            args.Add("--mcp-config");
            args.Add(mcpConfigPath);
        }

        return await RunCliStreamingAsync(args, prompt, onEvent, cancellationToken);
    }

    private async Task<CliChatResult> RunCliStreamingAsync(
        List<string> args,
        string stdinPrompt,
        Func<CliStreamEvent, Task> onEvent,
        CancellationToken cancellationToken)
    {
        var result = new CliChatResult();
        var fullOutput = new StringBuilder();
        var error = new StringBuilder();

        // Tracking für content blocks
        string currentBlockType = null;   // "text" oder "tool_use"
        string currentToolName = null;
        string currentToolId = null;
        var currentToolInput = new StringBuilder();
        bool inTextBlock = false;

        var lineBuffer = new StringBuilder();

        try
        {
            var startInfo = CreateCliStartInfo(args, redirectInput: true);

            using var process = new Process { StartInfo = startInfo };

            process.ErrorDataReceived += (s, e) =>
            {
                if (e.Data != null)
                {
                    error.AppendLine(e.Data);
                    _logger.LogDebug("CLI stderr: {Line}", e.Data);
                }
            };

            process.Start();
            process.BeginErrorReadLine();

            // Bei Cancellation den gesamten Prozessbaum beenden
            // (ReadLineAsync wirft OperationCanceledException, aber process.Dispose() killt NICHT den Prozess)
            using var killOnCancel = cancellationToken.Register(() =>
            {
                try { if (!process.HasExited) process.Kill(entireProcessTree: true); } catch { }
            });

            await process.StandardInput.WriteAsync(stdinPrompt);
            await process.StandardInput.FlushAsync();
            process.StandardInput.Close();

            using var reader = process.StandardOutput;
            string line;
            while ((line = await reader.ReadLineAsync(cancellationToken)) != null)
            {

                if (!line.StartsWith("{"))
                    continue;

                try
                {
                    var json = JsonSerializer.Deserialize<JsonElement>(line);
                    var type = json.TryGetProperty("type", out var t) ? t.GetString() : null;

                    if (type == "stream_event" && json.TryGetProperty("event", out var evt))
                    {
                        var evtType = evt.TryGetProperty("type", out var et) ? et.GetString() : null;

                        switch (evtType)
                        {
                            case "content_block_start":
                            {
                                if (evt.TryGetProperty("content_block", out var cb))
                                {
                                    var cbType = cb.TryGetProperty("type", out var cbt) ? cbt.GetString() : null;

                                    if (cbType == "text")
                                    {
                                        currentBlockType = "text";
                                        if (!inTextBlock)
                                        {
                                            inTextBlock = true;
                                            await onEvent(new CliStreamEvent { Type = CliEventType.TextStart });
                                        }
                                    }
                                    else if (cbType == "tool_use")
                                    {
                                        // Text-Block vorher abschließen + lineBuffer flushen
                                        if (inTextBlock)
                                        {
                                            // Restlichen Text im lineBuffer emittieren bevor Tool startet
                                            if (lineBuffer.Length > 0)
                                            {
                                                var remaining = lineBuffer.ToString();
                                                lineBuffer.Clear();
                                                if (remaining.Trim().Length > 0)
                                                {
                                                    fullOutput.Append(remaining);
                                                    await onEvent(new CliStreamEvent { Type = CliEventType.TextDelta, Text = remaining });
                                                }
                                            }
                                            inTextBlock = false;
                                            await onEvent(new CliStreamEvent { Type = CliEventType.TextEnd });
                                        }

                                        currentBlockType = "tool_use";
                                        currentToolName = cb.TryGetProperty("name", out var n) ? n.GetString() : "unknown";
                                        currentToolId = cb.TryGetProperty("id", out var id) ? id.GetString() : "";
                                        currentToolInput.Clear();

                                        await onEvent(new CliStreamEvent
                                        {
                                            Type = CliEventType.ToolStart,
                                            ToolName = currentToolName,
                                            ToolId = currentToolId
                                        });
                                    }
                                }
                                break;
                            }

                            case "content_block_delta":
                            {
                                if (evt.TryGetProperty("delta", out var delta))
                                {
                                    var deltaType = delta.TryGetProperty("type", out var dt) ? dt.GetString() : null;

                                    if (deltaType == "text_delta" && delta.TryGetProperty("text", out var txt))
                                    {
                                        var text = txt.GetString();
                                        if (!string.IsNullOrEmpty(text))
                                        {
                                            for (int ci = 0; ci < text.Length; ci++)
                                            {
                                                var ch = text[ci];
                                                if (ch == '\n')
                                                {
                                                    var completedLine = lineBuffer.ToString().Trim();
                                                    lineBuffer.Clear();

                                                    if (completedLine.Length > 0 || fullOutput.Length > 0)
                                                    {
                                                        var lineText = completedLine + "\n";
                                                        fullOutput.Append(lineText);
                                                        await onEvent(new CliStreamEvent { Type = CliEventType.TextDelta, Text = lineText });
                                                    }
                                                }
                                                else
                                                {
                                                    lineBuffer.Append(ch);
                                                }
                                            }
                                        }
                                    }
                                    else if (deltaType == "input_json_delta" && delta.TryGetProperty("partial_json", out var pj))
                                    {
                                        currentToolInput.Append(pj.GetString());
                                    }
                                }
                                break;
                            }

                            case "content_block_stop":
                            {
                                if (currentBlockType == "tool_use")
                                {
                                    await onEvent(new CliStreamEvent
                                    {
                                        Type = CliEventType.ToolEnd,
                                        ToolName = currentToolName,
                                        ToolId = currentToolId,
                                        ToolInput = currentToolInput.ToString()
                                    });
                                    currentBlockType = null;
                                    currentToolName = null;
                                    currentToolId = null;
                                    currentToolInput.Clear();
                                }
                                else if (currentBlockType == "text")
                                {
                                    // lineBuffer flushen (Text ohne trailing \n)
                                    if (lineBuffer.Length > 0)
                                    {
                                        var remaining = lineBuffer.ToString();
                                        lineBuffer.Clear();
                                        if (remaining.Trim().Length > 0)
                                        {
                                            fullOutput.Append(remaining);
                                            await onEvent(new CliStreamEvent { Type = CliEventType.TextDelta, Text = remaining });
                                        }
                                    }
                                    currentBlockType = null;
                                }
                                break;
                            }
                        }
                    }
                    else if (type == "result")
                    {
                        // Restlichen lineBuffer flushen (nicht-abgeschlossene Zeile)
                        if (lineBuffer.Length > 0)
                        {
                            var remaining = lineBuffer.ToString().Trim();
                            lineBuffer.Clear();

                            if (remaining.Length > 0)
                            {
                                fullOutput.Append(remaining);
                                await onEvent(new CliStreamEvent { Type = CliEventType.TextDelta, Text = remaining });
                            }
                        }

                        // Offenen Text-Block abschließen
                        if (inTextBlock)
                        {
                            inTextBlock = false;
                            await onEvent(new CliStreamEvent { Type = CliEventType.TextEnd });
                        }

                        if (json.TryGetProperty("usage", out var usage))
                        {
                            result.InputTokens = usage.TryGetProperty("input_tokens", out var it) ? it.GetInt64() : 0;
                            result.OutputTokens = usage.TryGetProperty("output_tokens", out var ot) ? ot.GetInt64() : 0;
                            result.CacheReadTokens = usage.TryGetProperty("cache_read_input_tokens", out var cr) ? cr.GetInt64() : 0;
                            result.CacheCreationTokens = usage.TryGetProperty("cache_creation_input_tokens", out var cc) ? cc.GetInt64() : 0;
                        }
                        if (json.TryGetProperty("total_cost_usd", out var cost))
                            result.CostUsd = cost.GetDouble();
                        if (json.TryGetProperty("duration_api_ms", out var dur))
                            result.DurationApiMs = dur.GetInt64();
                        if (json.TryGetProperty("session_id", out var sid))
                            result.SessionId = sid.GetString();
                        if (json.TryGetProperty("num_turns", out var nt))
                            result.NumTurns = nt.GetInt32();

                        var isError = json.TryGetProperty("is_error", out var ie) && ie.GetBoolean();
                        if (isError)
                            result.Error = json.TryGetProperty("result", out var errMsg) ? errMsg.GetString() : "CLI error";
                    }
                    else if (type == "user" && json.TryGetProperty("message", out var userMsg))
                    {
                        // CLI sendet tool_result als type:"user" message
                        if (userMsg.TryGetProperty("content", out var content) && content.ValueKind == JsonValueKind.Array)
                        {
                            foreach (var item in content.EnumerateArray())
                            {
                                var itemType = item.TryGetProperty("type", out var iType) ? iType.GetString() : null;
                                if (itemType == "tool_result")
                                {
                                    var toolUseId = item.TryGetProperty("tool_use_id", out var tuId) ? tuId.GetString() : "";
                                    var resultIsError = item.TryGetProperty("is_error", out var isErr) && isErr.GetBoolean();

                                    // Content kann string oder array sein
                                    var resultContent = "";
                                    if (item.TryGetProperty("content", out var rc))
                                    {
                                        if (rc.ValueKind == JsonValueKind.String)
                                            resultContent = rc.GetString();
                                        else if (rc.ValueKind == JsonValueKind.Array)
                                        {
                                            var sb = new StringBuilder();
                                            foreach (var part in rc.EnumerateArray())
                                            {
                                                if (part.TryGetProperty("text", out var partText))
                                                    sb.Append(partText.GetString());
                                            }
                                            resultContent = sb.ToString();
                                        }
                                    }

                                    await onEvent(new CliStreamEvent
                                    {
                                        Type = CliEventType.ToolResult,
                                        ToolId = toolUseId,
                                        ToolResultContent = resultContent,
                                        ToolResultIsError = resultIsError
                                    });
                                }
                            }
                        }
                    }
                }
                catch (JsonException ex)
                {
                    _logger.LogDebug("CLI JSON parse error: {Error} for line: {Line}", ex.Message, line.Length > 200 ? line[..200] : line);
                }
            }

            // Restlichen lineBuffer flushen
            if (lineBuffer.Length > 0)
            {
                var remaining = lineBuffer.ToString().Trim();
                lineBuffer.Clear();

                if (remaining.Length > 0)
                {
                    fullOutput.Append(remaining);
                    await onEvent(new CliStreamEvent { Type = CliEventType.TextDelta, Text = remaining });
                }
            }

            // Sicherstellen, dass offene Blöcke geschlossen werden
            if (currentBlockType == "tool_use" && currentToolName != null)
            {
                await onEvent(new CliStreamEvent
                {
                    Type = CliEventType.ToolEnd,
                    ToolName = currentToolName,
                    ToolId = currentToolId,
                    ToolInput = currentToolInput.ToString()
                });
                currentBlockType = null;
            }
            if (inTextBlock)
                await onEvent(new CliStreamEvent { Type = CliEventType.TextEnd });

            await process.WaitForExitAsync(cancellationToken);

            result.ExitCode = process.ExitCode;
            result.Output = fullOutput.ToString().Trim();
            result.Success = process.ExitCode == 0 && fullOutput.Length > 0;

            if (!result.Success && string.IsNullOrEmpty(result.Error))
                result.Error = error.Length > 0 ? error.ToString().Trim() : $"CLI exit code: {process.ExitCode}";
        }
        catch (OperationCanceledException)
        {
            result.Success = false;
            result.Error = "Abgebrochen";
            throw;
        }
        catch (Exception ex)
        {
            result.Success = false;
            result.Error = ex.Message;
            _logger.LogError(ex, "Fehler beim Streaming der Claude CLI");
        }

        return result;
    }

    /// <summary>
    /// Prüft ob die CLI funktioniert und authentifiziert ist.
    /// </summary>
    public async Task<CliStatusResult> GetStatusAsync()
    {
        var result = new CliStatusResult { IsAvailable = _isAvailable };

        if (!_isAvailable)
        {
            result.Error = "Claude CLI nicht gefunden";
            return result;
        }

        try
        {
            var versionResult = await RunSimpleAsync(["--version"], CancellationToken.None);
            if (versionResult.Success)
                result.Version = versionResult.Output.Trim();

            var doctorResult = await RunSimpleAsync(["doctor"], CancellationToken.None);
            result.IsAuthenticated = doctorResult.Success;

            if (!doctorResult.Success)
                result.Error = doctorResult.Error ?? doctorResult.Output;
        }
        catch (Exception ex)
        {
            result.Error = ex.Message;
        }

        return result;
    }

    private async Task<CliChatResult> RunSimpleAsync(List<string> args, CancellationToken cancellationToken)
    {
        var result = new CliChatResult();
        var output = new StringBuilder();
        var error = new StringBuilder();

        try
        {
            var startInfo = CreateCliStartInfo(args);

            using var process = new Process { StartInfo = startInfo };
            process.OutputDataReceived += (s, e) => { if (e.Data != null) output.AppendLine(e.Data); };
            process.ErrorDataReceived += (s, e) => { if (e.Data != null) error.AppendLine(e.Data); };

            process.Start();
            process.BeginOutputReadLine();
            process.BeginErrorReadLine();

            using var killOnCancel = cancellationToken.Register(() =>
            {
                try { if (!process.HasExited) process.Kill(entireProcessTree: true); } catch { }
            });

            await process.WaitForExitAsync(cancellationToken);

            result.ExitCode = process.ExitCode;
            result.Output = output.ToString().Trim();
            result.Success = process.ExitCode == 0;

            if (!result.Success)
                result.Error = error.Length > 0 ? error.ToString().Trim() : $"Exit code: {process.ExitCode}";
        }
        catch (OperationCanceledException)
        {
            result.Success = false;
            result.Error = "Abgebrochen";
            throw;
        }
        catch (Exception ex)
        {
            result.Success = false;
            result.Error = ex.Message;
            _logger.LogError(ex, "Fehler beim Ausführen der Claude CLI");
        }

        return result;
    }
}

public enum CliEventType
{
    TextStart,
    TextDelta,
    TextEnd,
    ToolStart,
    ToolEnd,
    ToolResult
}

public class CliStreamEvent
{
    public CliEventType Type { get; set; }
    public string Text { get; set; }
    public string ToolName { get; set; }
    public string ToolId { get; set; }
    public string ToolInput { get; set; }
    public string ToolResultContent { get; set; }
    public bool ToolResultIsError { get; set; }
}

public class CliChatResult
{
    public bool Success { get; set; }
    public string Output { get; set; }
    public string Error { get; set; }
    public int ExitCode { get; set; }
    public long InputTokens { get; set; }
    public long OutputTokens { get; set; }
    public long CacheReadTokens { get; set; }
    public long CacheCreationTokens { get; set; }
    public double CostUsd { get; set; }
    public long DurationApiMs { get; set; }
    public string SessionId { get; set; }
    public int NumTurns { get; set; }
}

public class CliStatusResult
{
    public bool IsAvailable { get; set; }
    public bool IsAuthenticated { get; set; }
    public string Version { get; set; }
    public string Error { get; set; }
}