using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text.Json;
using System.Threading.Tasks;
using Gott.Models;

namespace Gott.Services;

public class ChatService
{
    private readonly DatabaseService _db;
    private readonly ToolService _toolService;
    private readonly MemoryService _memoryService;
    private readonly SkillService _skillService;

    public ChatService(DatabaseService db, ToolService toolService, MemoryService memoryService, SkillService skillService)
    {
        _db = db;
        _toolService = toolService;
        _memoryService = memoryService;
        _skillService = skillService;
    }

    public static string ResolveModelId(string model)
    {
        return model switch
        {
            "sonnet" => "claude-sonnet-4-6",
            "sonnet-4-5" => "claude-sonnet-4-5",
            "sonnet-4-6" => "claude-sonnet-4-6",
            "opus" => "claude-opus-4-6",
            "opus-4-5" => "claude-opus-4-5",
            "opus-4-6" => "claude-opus-4-6",
            "haiku" => "claude-haiku-4-5",
            "haiku-4-5" => "claude-haiku-4-5",
            _ => "claude-sonnet-4-6"
        };
    }

    /// <summary>
    /// Baut den vollständigen ChatContext auf: Agent, Model, SystemPrompt, Chain, Workspace etc.
    /// </summary>
    public async Task<ChatContext> PrepareContext(string sessionId, string userId, int maxIterations = 100)
    {
        var session = await _db.GetSession(sessionId);
        if (session == null || (userId != null && session.UserId != userId) || string.IsNullOrEmpty(session.AgentId))
            return null;

        var agent = await _db.GetAgent(session.AgentId);
        if (agent == null)
            return null;

        var modelId = ResolveModelId(agent.Model);

        var markedMessages = await _db.GetMarkedMessages(sessionId);
        var agentMemoryDir = _memoryService.GetAgentMemoryDir(agent.AgentId);
        var agentSkills = await _db.GetAgentSkills(agent.AgentId);
        var user = userId != null ? await _db.GetUser(userId) : null;
        var systemPromptText = SystemPromptBuilder.Build(
            agent, session, markedMessages, _memoryService, agentMemoryDir,
            agentSkills, _skillService, userPersona: user?.GetEffectivePersona());

        var workspace = session.Workspace;
        if (string.IsNullOrEmpty(workspace) && agentSkills.Any())
            workspace = "/tmp";

        var toolChoice = agent.ToolChoice ?? "any";
        var hasWorkspace = !string.IsNullOrEmpty(workspace);
        var includeMemory = agent.UseMemory && !string.IsNullOrEmpty(agent.AgentId);

        var toolDefs = (hasWorkspace || includeMemory)
            ? _toolService.GetToolDefinitions(includeFileTools: hasWorkspace, includeMemory: includeMemory)
            : Array.Empty<object>();
        var toolNames = toolDefs.Length > 0
            ? JsonSerializer.Serialize(toolDefs.Select(td =>
            {
                var json = JsonSerializer.Serialize(td);
                var el = JsonSerializer.Deserialize<JsonElement>(json);
                return el.GetProperty("name").GetString();
            }).ToArray())
            : null;

        var chainId = Guid.NewGuid().ToString("N");

        await _db.CreateChain(new ChainRecord
        {
            ChainId = chainId,
            SessionId = sessionId,
            AgentId = agent.AgentId,
            Model = modelId,
            SystemPrompt = systemPromptText,
            ToolChoice = (hasWorkspace || includeMemory) ? toolChoice : null,
            ToolNames = toolNames
        });

        await _db.UpdateSessionTimestamp(sessionId);

        if (!string.IsNullOrEmpty(workspace))
            Directory.CreateDirectory(workspace);

        var systemPrompt = new List<object>();
        if (!string.IsNullOrWhiteSpace(systemPromptText))
            systemPrompt.Add(new { type = "text", text = systemPromptText });

        return new ChatContext
        {
            ChainId = chainId,
            SessionId = sessionId,
            ModelId = modelId,
            Workspace = workspace,
            AgentId = agent.AgentId,
            SystemPromptText = systemPromptText,
            SystemPrompt = systemPrompt,
            ToolChoice = toolChoice,
            UseMemory = agent.UseMemory,
            WebSearchVersion = agent.WebSearchVersion,
            MaxIterations = maxIterations,
            Agent = agent,
            Session = session
        };
    }

    /// <summary>
    /// Baut die Message-History aus der DB (aktive Chains).
    /// Optimiert: Nur Text-Messages (user/assistant) für ältere Chains,
    /// Tool-Calls nur für die aktuelle Chain, Attachments nur für die letzte User-Message.
    /// </summary>
    public async Task<List<object>> BuildHistoryFromDb(string sessionId)
    {
        var chainsList = (await _db.GetActiveChains(sessionId)).ToList();
        // chronologisch sortieren (älteste zuerst)
        chainsList.Reverse();

        var history = new List<object>();
        var isLastChain = false;
        long? lastUserMsgId = null;

        for (int i = 0; i < chainsList.Count; i++)
        {
            var chain = chainsList[i];
            isLastChain = (i == chainsList.Count - 1);

            var msgs = (await _db.GetChainMessages(chain.ChainId)).ToList();

            // Letzte User-Message-ID der letzten Chain merken (für Attachments)
            if (isLastChain)
            {
                var lastUserMsg = msgs.LastOrDefault(m => m.Role == "user" && m.Type == "text");
                lastUserMsgId = lastUserMsg?.Id;
            }

            // Für ältere Chains: nur Text-Messages (wie Frontend es vorher gemacht hat)
            if (!isLastChain)
            {
                foreach (var msg in msgs)
                {
                    if (msg.Role == "user" && msg.Type == "text" && !string.IsNullOrEmpty(msg.Content))
                    {
                        history.Add(new Dictionary<string, object>
                        {
                            ["role"] = "user",
                            ["content"] = new List<object> { new { type = "text", text = msg.Content } }
                        });
                    }
                    else if (msg.Role == "assistant" && msg.Type == "text" && !string.IsNullOrEmpty(msg.Content))
                    {
                        history.Add(new Dictionary<string, object>
                        {
                            ["role"] = "assistant",
                            ["content"] = new List<object> { new { type = "text", text = msg.Content } }
                        });
                    }
                }
                continue;
            }

            // Letzte Chain: vollständig mit Tool-Calls
            var grouped = new Dictionary<int, List<MessageRecord>>();
            foreach (var msg in msgs)
            {
                if (!grouped.ContainsKey(msg.Iteration))
                    grouped[msg.Iteration] = new List<MessageRecord>();
                grouped[msg.Iteration].Add(msg);
            }

            foreach (var kvp in grouped.OrderBy(x => x.Key))
            {
                foreach (var msg in kvp.Value)
                {
                    if (msg.Role == "user" && msg.Type == "text")
                    {
                        var content = new List<object>();

                        // Attachments nur für die letzte User-Message laden
                        if (msg.Id == lastUserMsgId)
                        {
                            var attachments = await _db.GetAttachments(msg.Id);
                            foreach (var att in attachments)
                            {
                                if (att.Type == "image")
                                {
                                    content.Add(new
                                    {
                                        type = "image",
                                        source = new { type = "base64", media_type = att.MediaType, data = att.Data }
                                    });
                                }
                                else if (att.Type == "document")
                                {
                                    content.Add(new
                                    {
                                        type = "document",
                                        source = new { type = "base64", media_type = att.MediaType, data = att.Data }
                                    });
                                }
                            }
                        }

                        if (!string.IsNullOrEmpty(msg.Content))
                            content.Add(new { type = "text", text = msg.Content });

                        if (content.Count > 0)
                            history.Add(new Dictionary<string, object> { ["role"] = "user", ["content"] = content });
                    }
                    else if (msg.Role == "assistant" && msg.Type == "text")
                    {
                        if (!string.IsNullOrEmpty(msg.Content))
                        {
                            history.Add(new Dictionary<string, object>
                            {
                                ["role"] = "assistant",
                                ["content"] = new List<object> { new { type = "text", text = msg.Content } }
                            });
                        }
                    }
                    else if (msg.Role == "assistant" && msg.Type == "tool_use")
                    {
                        JsonElement inputEl;
                        try { inputEl = JsonSerializer.Deserialize<JsonElement>(msg.Content ?? "{}"); }
                        catch { inputEl = JsonSerializer.Deserialize<JsonElement>("{}"); }

                        var lastAssistant = history.Count > 0 ? history[history.Count - 1] : null;
                        if (lastAssistant is Dictionary<string, object> dict &&
                            dict.TryGetValue("role", out var role) && role.ToString() == "assistant" &&
                            dict.TryGetValue("content", out var existingContent) && existingContent is List<object> contentList)
                        {
                            contentList.Add(new { type = "tool_use", id = msg.ToolCallId, name = msg.ToolName, input = inputEl });
                        }
                        else
                        {
                            history.Add(new Dictionary<string, object>
                            {
                                ["role"] = "assistant",
                                ["content"] = new List<object>
                                {
                                    new { type = "tool_use", id = msg.ToolCallId, name = msg.ToolName, input = inputEl }
                                }
                            });
                        }
                    }
                    else if (msg.Role == "user" && msg.Type == "tool_result")
                    {
                        var lastUser = history.Count > 0 ? history[history.Count - 1] : null;
                        if (lastUser is Dictionary<string, object> dict &&
                            dict.TryGetValue("role", out var role) && role.ToString() == "user" &&
                            dict.TryGetValue("content", out var existingContent) && existingContent is List<object> contentList)
                        {
                            contentList.Add(new { type = "tool_result", tool_use_id = msg.ToolCallId, content = msg.Content ?? "", is_error = msg.IsError });
                        }
                        else
                        {
                            history.Add(new Dictionary<string, object>
                            {
                                ["role"] = "user",
                                ["content"] = new List<object>
                                {
                                    new { type = "tool_result", tool_use_id = msg.ToolCallId, content = msg.Content ?? "", is_error = msg.IsError }
                                }
                            });
                        }
                    }
                }
            }
        }

        return history;
    }
}