using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Text.Json;
using System.Text.Json.Serialization;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddHttpClient();

var app = builder.Build();
app.UseDefaultFiles();
app.UseStaticFiles();

// Workspace-Root für Dateioperationen
var dataDir = Path.Combine(AppContext.BaseDirectory, "data");
var workspaceRoot = Path.Combine(dataDir, "workspace");
Directory.CreateDirectory(workspaceRoot);

var toolDefs = new[]
{
    new
    {
        name = "read_file",
        description = "Liest den Inhalt einer Datei. Gibt den Textinhalt zurück.",
        input_schema = new
        {
            type = "object",
            properties = new Dictionary<string, object>
            {
                ["path"] = new { type = "string", description = "Relativer Dateipfad" }
            },
            required = new[] { "path" }
        }
    },
    new
    {
        name = "write_file",
        description = "Erstellt oder überschreibt eine Datei mit dem angegebenen Inhalt.",
        input_schema = new
        {
            type = "object",
            properties = new Dictionary<string, object>
            {
                ["path"] = new { type = "string", description = "Relativer Dateipfad" },
                ["content"] = new { type = "string", description = "Dateiinhalt" }
            },
            required = new[] { "path", "content" }
        }
    },
    new
    {
        name = "edit_file",
        description = "Ersetzt einen exakten Textabschnitt in einer Datei. oldText muss exakt matchen.",
        input_schema = new
        {
            type = "object",
            properties = new Dictionary<string, object>
            {
                ["path"] = new { type = "string", description = "Relativer Dateipfad" },
                ["old_text"] = new { type = "string", description = "Exakter Text der ersetzt werden soll" },
                ["new_text"] = new { type = "string", description = "Neuer Text" }
            },
            required = new[] { "path", "old_text", "new_text" }
        }
    },
    new
    {
        name = "list_files",
        description = "Listet Dateien und Ordner in einem Verzeichnis auf.",
        input_schema = new
        {
            type = "object",
            properties = new Dictionary<string, object>
            {
                ["path"] = new { type = "string", description = "Relativer Verzeichnispfad (leer = Root)" }
            },
            required = System.Array.Empty<string>()
        }
    }
};

string ResolvePath(string relativePath)
{
    var full = Path.GetFullPath(Path.Combine(workspaceRoot, relativePath ?? ""));
    if (!full.StartsWith(workspaceRoot))
        throw new System.Exception("Zugriff außerhalb des Workspace nicht erlaubt");
    return full;
}

string ExecuteTool(string name, JsonElement input)
{
    switch (name)
    {
        case "read_file":
        {
            var path = ResolvePath(input.GetProperty("path").GetString() ?? "");
            if (!File.Exists(path))
                return $"Fehler: Datei nicht gefunden: {Path.GetRelativePath(workspaceRoot, path)}";
            return File.ReadAllText(path);
        }
        case "write_file":
        {
            var path = ResolvePath(input.GetProperty("path").GetString() ?? "");
            var dir = Path.GetDirectoryName(path);
            if (dir != null) Directory.CreateDirectory(dir);
            var content = input.GetProperty("content").GetString() ?? "";
            File.WriteAllText(path, content);
            return $"Datei geschrieben: {Path.GetRelativePath(workspaceRoot, path)} ({content.Length} Zeichen)";
        }
        case "edit_file":
        {
            var path = ResolvePath(input.GetProperty("path").GetString() ?? "");
            if (!File.Exists(path))
                return $"Fehler: Datei nicht gefunden: {Path.GetRelativePath(workspaceRoot, path)}";
            var fileContent = File.ReadAllText(path);
            var oldText = input.GetProperty("old_text").GetString() ?? "";
            var newText = input.GetProperty("new_text").GetString() ?? "";
            if (!fileContent.Contains(oldText))
                return "Fehler: old_text nicht in der Datei gefunden. Exakter Match nötig.";
            fileContent = fileContent.Replace(oldText, newText);
            File.WriteAllText(path, fileContent);
            return $"Datei bearbeitet: {Path.GetRelativePath(workspaceRoot, path)}";
        }
        case "list_files":
        {
            var path = ResolvePath(input.TryGetProperty("path", out var p) ? p.GetString() ?? "" : "");
            if (!Directory.Exists(path))
                return $"Fehler: Verzeichnis nicht gefunden: {Path.GetRelativePath(workspaceRoot, path)}";
            var entries = new List<string>();
            foreach (var dir in Directory.GetDirectories(path))
                entries.Add(Path.GetRelativePath(workspaceRoot, dir) + "/");
            foreach (var file in Directory.GetFiles(path))
                entries.Add(Path.GetRelativePath(workspaceRoot, file));
            return entries.Count == 0 ? "(leer)" : string.Join("\n", entries);
        }
        default:
            return $"Fehler: Unbekanntes Tool: {name}";
    }
}

app.MapPost("/api/chat", async (HttpRequest req, IHttpClientFactory httpFactory, IConfiguration config) =>
{
    var body = await JsonSerializer.DeserializeAsync<ChatRequest>(req.Body);
    if (body == null || body.Messages == null || body.Messages.Count == 0)
        return Results.BadRequest(new { error = "messages required" });

    var token = config["AnthropicToken"];
    if (string.IsNullOrEmpty(token))
        return Results.Problem("AnthropicToken not configured");

    var modelId = body.Model switch
    {
        "opus" => "claude-opus-4-6",
        "sonnet" => "claude-sonnet-4-6",
        _ => "claude-sonnet-4-6"
    };

    // Messages in API-Format konvertieren
    var messages = new List<object>();
    foreach (var msg in body.Messages)
    {
        messages.Add(new { role = msg.Role, content = msg.Content });
    }

    var systemPrompt = new List<object>
    {
        new { type = "text", text = "You are Claude Code, Anthropic's official CLI for Claude." }
    };
    if (!string.IsNullOrWhiteSpace(body.SystemPrompt))
    {
        systemPrompt.Add(new { type = "text", text = body.SystemPrompt });
    }

    var steps = new List<StepInfo>();
    long totalInputTokens = 0;
    long totalOutputTokens = 0;
    int iterations = 0;
    int maxIterations = 25;

    while (iterations < maxIterations)
    {
        iterations++;

        var payload = new Dictionary<string, object>
        {
            ["model"] = modelId,
            ["max_tokens"] = 4096,
            ["system"] = systemPrompt,
            ["messages"] = messages,
            ["tools"] = toolDefs
        };

        var client = httpFactory.CreateClient();
        client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);
        client.DefaultRequestHeaders.Add("anthropic-version", "2023-06-01");
        client.DefaultRequestHeaders.Add("anthropic-beta", "claude-code-20250219,oauth-2025-04-20");
        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");

        var json = JsonSerializer.Serialize(payload);
        var httpContent = new StringContent(json, Encoding.UTF8, "application/json");

        var resp = await client.PostAsync("https://api.anthropic.com/v1/messages", httpContent);
        var respBody = await resp.Content.ReadAsStringAsync();

        if (!resp.IsSuccessStatusCode)
            return Results.Problem($"Anthropic API error: {(int)resp.StatusCode} - {respBody}");

        var result = JsonSerializer.Deserialize<JsonElement>(respBody);

        // Usage tracken
        if (result.TryGetProperty("usage", out var usage))
        {
            if (usage.TryGetProperty("input_tokens", out var it)) totalInputTokens += it.GetInt64();
            if (usage.TryGetProperty("output_tokens", out var ot)) totalOutputTokens += ot.GetInt64();
        }

        var stopReason = result.GetProperty("stop_reason").GetString();
        var contentBlocks = result.GetProperty("content");

        // Assistant-Antwort zur History hinzufügen
        var assistantContent = new List<object>();
        var textParts = new List<string>();

        foreach (var block in contentBlocks.EnumerateArray())
        {
            var blockType = block.GetProperty("type").GetString();
            if (blockType == "text")
            {
                var text = block.GetProperty("text").GetString() ?? "";
                textParts.Add(text);
                assistantContent.Add(new { type = "text", text });
            }
            else if (blockType == "tool_use")
            {
                var toolId = block.GetProperty("id").GetString() ?? "";
                var toolName = block.GetProperty("name").GetString() ?? "";
                var toolInput = block.GetProperty("input");

                assistantContent.Add(new
                {
                    type = "tool_use",
                    id = toolId,
                    name = toolName,
                    input = toolInput
                });
            }
        }

        messages.Add(new { role = "assistant", content = assistantContent });

        // Zwischen-Text als Step erfassen
        if (textParts.Count > 0)
        {
            steps.Add(new StepInfo
            {
                Type = "text",
                Text = string.Join("\n", textParts)
            });
        }

        // Kein Tool Use? Fertig!
        if (stopReason != "tool_use")
        {
            return Results.Ok(new
            {
                text = string.Join("\n", textParts),
                model = modelId,
                inputTokens = totalInputTokens,
                outputTokens = totalOutputTokens,
                iterations,
                steps
            });
        }

        // Tool Calls ausführen
        var toolResults = new List<object>();
        foreach (var block in contentBlocks.EnumerateArray())
        {
            if (block.GetProperty("type").GetString() != "tool_use") continue;

            var toolId = block.GetProperty("id").GetString() ?? "";
            var toolName = block.GetProperty("name").GetString() ?? "";
            var toolInput = block.GetProperty("input");

            string toolResult;
            bool isError = false;
            try
            {
                toolResult = ExecuteTool(toolName, toolInput);
            }
            catch (System.Exception ex)
            {
                toolResult = $"Fehler: {ex.Message}";
                isError = true;
            }

            steps.Add(new StepInfo
            {
                Type = "tool",
                ToolName = toolName,
                ToolInput = toolInput.ToString(),
                ToolResult = toolResult.Length > 500 ? toolResult[..500] + "..." : toolResult,
                IsError = isError
            });

            toolResults.Add(new
            {
                type = "tool_result",
                tool_use_id = toolId,
                content = toolResult,
                is_error = isError
            });
        }

        messages.Add(new { role = "user", content = toolResults });
    }

    return Results.Problem("Max iterations erreicht");
});

app.Run("http://0.0.0.0:19000");

class ChatMessage
{
    [JsonPropertyName("role")]
    public string Role { get; set; } = "";

    [JsonPropertyName("content")]
    public string Content { get; set; } = "";
}

class ChatRequest
{
    [JsonPropertyName("model")]
    public string Model { get; set; } = "sonnet";

    [JsonPropertyName("messages")]
    public List<ChatMessage> Messages { get; set; } = new();

    [JsonPropertyName("systemPrompt")]
    public string SystemPrompt { get; set; } = "";
}

class StepInfo
{
    [JsonPropertyName("type")]
    public string Type { get; set; } = "";

    [JsonPropertyName("text")]
    public string Text { get; set; } = "";

    [JsonPropertyName("toolName")]
    public string ToolName { get; set; } = "";

    [JsonPropertyName("toolInput")]
    public string ToolInput { get; set; } = "";

    [JsonPropertyName("toolResult")]
    public string ToolResult { get; set; } = "";

    [JsonPropertyName("isError")]
    public bool IsError { get; set; }
}