import { Router } from "express";
import { getSession, addMessage } from "../services/sessionStore.js";
import {
    getOllamaModel,
    buildLangChainMessages,
    aiMessageToClaudeResponse
} from "../services/langchainModels.js";

const router = Router();

router.post("/*path", async (req, res) => {
    const requestStart = Date.now();
    console.log(`[Ollama API] ========== REQUEST START ==========`);

    const { sessionId, model: modelId, max_tokens, system: systemPrompt, messages } = req.body;

    console.log(`[Ollama API] Session ID: ${sessionId || 'none'}`);
    console.log(`[Ollama API] Model: ${modelId}`);
    console.log(`[Ollama API] Messages count: ${messages?.length || 0}`);

    try {
        // Get LangChain model with tools bound
        const model = getOllamaModel(modelId);

        // Build messages with entity context and history
        const langChainMessages = buildLangChainMessages(
            sessionId,
            messages,
            systemPrompt
        );

        console.log(`[Ollama API] Sending request via LangChain...`);
        const fetchStart = Date.now();

        // Invoke model
        const response = await model.invoke(langChainMessages);

        const fetchDuration = Date.now() - fetchStart;
        console.log(`[Ollama API] Response received in ${fetchDuration}ms`);

        // Convert to Claude API format for client compatibility
        const claudeResponse = aiMessageToClaudeResponse(response, modelId);
        console.log(`[Ollama API] Response converted. Stop reason: ${claudeResponse.stop_reason}, content blocks: ${claudeResponse.content.length}`);

        // Store messages to session if applicable
        if (sessionId && claudeResponse.content) {
            const session = getSession(sessionId);
            if (session) {
                const userMessage = messages?.[messages.length - 1];
                if (userMessage && userMessage.role === 'user' && typeof userMessage.content === 'string') {
                    addMessage(sessionId, {
                        role: 'user',
                        content: userMessage.content
                    });
                    console.log(`[Ollama API] Stored user message to session`);
                }

                const assistantContent = claudeResponse.content
                    .filter(c => c.type === 'text')
                    .map(c => c.text)
                    .join('\n');

                if (assistantContent) {
                    addMessage(sessionId, {
                        role: 'assistant',
                        content: assistantContent
                    });
                    console.log(`[Ollama API] Stored assistant response to session (${assistantContent.length} chars)`);
                }
            }
        }

        const totalDuration = Date.now() - requestStart;
        console.log(`[Ollama API] ========== REQUEST COMPLETE (${totalDuration}ms) ==========`);
        res.json(claudeResponse);

    } catch (error) {
        const totalDuration = Date.now() - requestStart;
        console.error(`[Ollama API] ========== REQUEST FAILED (${totalDuration}ms) ==========`);
        console.error(`[Ollama API] Error:`, error);

        // Check if it's a connection error
        if (error.cause?.code === 'ECONNREFUSED' || error.message?.includes('ECONNREFUSED')) {
            return res.status(503).json({
                error: "Ollama is not running",
                details: `Could not connect to Ollama. Make sure Ollama is installed and running.`
            });
        }

        res.status(500).json({
            error: "Failed to call Ollama",
            details: error.message
        });
    }
});

export default router;