import { Router } from "express";
import { getSession, addMessage } from "../services/sessionStore.js";
import { trackUsage, getUsageSummary, formatCost, getSessionUsage } from "../services/usageTracker.js";
import { getCloudflareAccountId, getCloudflareApiToken } from "../services/providerConfig.js";
import { getCloudflareModel } from "../services/ChatCloudflare.js";
import { buildLangChainMessages, aiMessageToClaudeResponse } from "../services/langchainModels.js";

const router = Router();

// Context limits for Cloudflare models
const CLOUDFLARE_CONTEXT_LIMITS = {
    '@cf/mistralai/mistral-small-3.1-24b-instruct': 32000,
    '@hf/nousresearch/hermes-2-pro-mistral-7b': 8000,
    '@cf/meta/llama-3.3-70b-instruct-fp8-fast': 128000,
    '@cf/meta/llama-3.1-8b-instruct': 128000,
    '@cf/deepseek-ai/deepseek-r1-distill-qwen-32b': 32000,
    '@cf/qwen/qwen2.5-coder-32b-instruct': 32000
};

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

    const accountId = getCloudflareAccountId();
    const apiToken = getCloudflareApiToken();

    if (!accountId) {
        console.error(`[Cloudflare API] ERROR: Account ID not configured`);
        return res.status(500).json({ error: "Cloudflare account ID not configured" });
    }

    if (!apiToken) {
        console.error(`[Cloudflare API] ERROR: API token not configured`);
        return res.status(500).json({ error: "Cloudflare API token not configured" });
    }

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

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

    try {
        // Get LangChain-compatible Cloudflare model with tools bound
        const model = getCloudflareModel(modelId);

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

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

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

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

        // Convert to Claude API format for client compatibility
        const data = aiMessageToClaudeResponse(response, modelId);
        console.log(`[Cloudflare API] Response converted. Stop reason: ${data.stop_reason}, content blocks: ${data.content?.length || 0}`);

        // Track and log token usage
        if (data.usage) {
            const userMessage = messages?.[messages.length - 1];
            const inputText = typeof userMessage?.content === 'string' ? userMessage.content : null;

            const outputText = data.content
                ?.filter(c => c.type === 'text')
                .map(c => c.text)
                .join('\n') || null;

            const toolCalls = data.content
                ?.filter(c => c.type === 'tool_use')
                .map(c => ({ name: c.name, input: c.input })) || [];

            const contextLimit = CLOUDFLARE_CONTEXT_LIMITS[modelId] || 32000;
            const usageRecord = trackUsage(sessionId, modelId, data.usage, {
                inputText,
                outputText,
                toolCalls,
                contextLimit
            });
            console.log(`[Cloudflare API] REQUEST USAGE: ${getUsageSummary(usageRecord)}`);

            if (sessionId) {
                const sessionStats = getSessionUsage(sessionId);
                if (sessionStats) {
                    console.log(`[Cloudflare API] SESSION TOTALS (${sessionStats.requestCount} requests):`);
                    console.log(`[Cloudflare API]   Total input:  ${sessionStats.totalInputTokens} tokens`);
                    console.log(`[Cloudflare API]   Total output: ${sessionStats.totalOutputTokens} tokens`);
                    console.log(`[Cloudflare API]   Total cost:   ${formatCost(sessionStats.totalCost)}`);
                    console.log(`[Cloudflare API]   Context:      ${sessionStats.contextUsed}/${sessionStats.contextLimit} (${sessionStats.contextPercent.toFixed(1)}%)`);

                    // Context warnings
                    if (sessionStats.contextPercent >= 95) {
                        console.error(`[Cloudflare API] ⚠️  CONTEXT CRITICAL: ${sessionStats.contextPercent.toFixed(0)}% used! Consider clearing conversation.`);
                    } else if (sessionStats.contextPercent >= 80) {
                        console.warn(`[Cloudflare API] ⚠️  CONTEXT WARNING: ${sessionStats.contextPercent.toFixed(0)}% of context window used`);
                    }
                }
            }
        }

        // Store messages to session
        if (sessionId && data.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(`[Cloudflare API] Stored user message to session`);
                }

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

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

        const totalDuration = Date.now() - requestStart;
        console.log(`[Cloudflare API] ========== REQUEST COMPLETE (${totalDuration}ms) ==========`);
        res.json(data);
    } catch (error) {
        const totalDuration = Date.now() - requestStart;
        console.error(`[Cloudflare API] ========== REQUEST FAILED (${totalDuration}ms) ==========`);
        console.error(`[Cloudflare API] Error:`, error);
        console.error(`[Cloudflare API] Error message:`, error.message);
        res.status(500).json({ error: "Failed to call Cloudflare API", details: error.message });
    }
});

export default router;