import * as http from 'http';
import * as fs from 'fs';
import {
    _getBrainDir,
    findBrainFiles,
    logError,
    logInfo,
    summarizeText
} from './utils';
import { getConfig } from './config';
import { IAIService, IBrainService, AIService, BrainService } from './core/services';

export interface BridgeInterface {
    injectSystemMessage(msg: string): void;
    getHistoryText(): string;
    sendPromptFromExtension(prompt: string): void;
    brainEnabled: boolean;
    findBrainFiles(dir: string): string[];
}

/**
 * BridgeServer: 
 * 외부 툴(EZER, A.U 등)과 Astra 확장을 연결하는 통신 브릿지.
 * 서비스 레이어(AIService, BrainService)를 통해 비즈니스 로직을 분리하여 유지보수성을 극대화했습니다.
 */
export class BridgeServer {
    private server: http.Server | null = null;
    private aiService: IAIService;
    private brainService: IBrainService;

    constructor(
        private provider: BridgeInterface,
        aiService?: IAIService,
        brainService?: IBrainService
    ) {
        // 의존성 주입 (DIP): 기본값 제공 및 외부 주입 허용
        this.aiService = aiService || new AIService();
        this.brainService = brainService || new BrainService();
    }

    public start(port: number = 4825) {
        this.server = http.createServer((req, res) => {
            res.setHeader('Access-Control-Allow-Origin', '*');
            res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS');
            res.setHeader('Access-Control-Allow-Headers', 'Content-Type');

            if (req.method === 'OPTIONS') {
                res.writeHead(200);
                res.end();
                return;
            }

            const url = req.url || '';
            const method = req.method;

            // 라우팅 로직 (SRP에 따라 비즈니스 로직은 서비스로 위임)
            if (method === 'GET' && url === '/ping') {
                this.handlePing(res);
            } else if (method === 'POST' && url === '/api/exam') {
                this.handlePost(req, res, this.processExam.bind(this));
            } else if (method === 'POST' && url === '/api/evaluate') {
                this.handlePost(req, res, this.processEvaluate.bind(this));
            } else if (method === 'GET' && url === '/api/evaluate-history') {
                this.processEvaluateHistory(res);
            } else if (method === 'POST' && url === '/api/brain-inject') {
                this.handlePost(req, res, this.processBrainInject.bind(this));
            } else {
                res.writeHead(404);
                res.end();
            }
        });

        this.server.on('error', (err: any) => {
            if (err.code === 'EADDRINUSE') {
                logError(`🚫 Bridge Port ${port} in use. Connection with EZER/A.U might fail.`);
            } else {
                logError(`Bridge server error:`, err);
            }
        });

        this.server.listen(port, '127.0.0.1', () => {
            logInfo(`Bridge server active on 127.0.0.1:${port}.`);
        });
    }

    private handlePing(res: http.ServerResponse) {
        const brainDir = _getBrainDir();
        const brainCount = fs.existsSync(brainDir) ? findBrainFiles(brainDir).length : 0;
        res.writeHead(200, { 'Content-Type': 'application/json' });
        res.end(JSON.stringify({
            status: 'ok',
            config: getConfig(),
            brain: { fileCount: brainCount, enabled: this.provider.brainEnabled }
        }));
    }

    private handlePost(req: http.IncomingMessage, res: http.ServerResponse, processor: (data: any, res: http.ServerResponse) => Promise<void>) {
        let body = '';
        req.on('data', chunk => body += chunk.toString());
        req.on('end', async () => {
            try {
                const parsed = JSON.parse(body);
                await processor(parsed, res);
            } catch (e: any) {
                logError('Bridge request processor failed.', { url: req.url, error: e.message });
                res.writeHead(500, { 'Content-Type': 'application/json' });
                res.end(JSON.stringify({ error: e.message }));
            }
        });
    }

    private async processExam(data: any, res: http.ServerResponse) {
        const prompt = data.prompt || 'Automatic Prompt';
        this.provider.sendPromptFromExtension(`[Bridge] ${prompt}`);
        const result = await this.aiService.call(prompt);
        res.writeHead(200, { 'Content-Type': 'application/json' });
        res.end(JSON.stringify({ success: true, rawOutput: result }));
    }

    private async processEvaluate(data: any, res: http.ServerResponse) {
        const prompt = data.prompt || '';
        this.provider.injectSystemMessage(`**[A.U Evaluation]** Analyzing input...`);
        const result = await this.aiService.call(`[EVALUATE] ${prompt}`);
        this.provider.injectSystemMessage(`**[Result]** ${summarizeText(result, 200)}`);
        res.writeHead(200, { 'Content-Type': 'application/json' });
        res.end(JSON.stringify({ rawOutput: result }));
    }

    private async processEvaluateHistory(res: http.ServerResponse) {
        const historyText = this.provider.getHistoryText();
        if (!historyText || historyText.length < 50) {
            res.writeHead(400, { 'Content-Type': 'application/json' });
            res.end(JSON.stringify({ error: "Insufficient history" }));
            return;
        }

        const result = await this.aiService.call(`Analyze chat history for metrics (JSON):\n${historyText.slice(-6000)}`);
        const jsonMatch = result.match(/\{[\s\S]*?\}/);
        res.writeHead(jsonMatch ? 200 : 500, { 'Content-Type': 'application/json' });
        res.end(jsonMatch ? jsonMatch[0] : JSON.stringify({ error: "Parse failed", raw: result }));
    }

    private async processBrainInject(data: any, res: http.ServerResponse) {
        const { title, markdown, prompt } = data;
        await this.brainService.inject(title, markdown);
        this.provider.injectSystemMessage(`**[Brain]** Knowledge captured: ${title}`);
        const result = await this.aiService.call(prompt || `Analyze: ${title}`);
        res.writeHead(200, { 'Content-Type': 'application/json' });
        res.end(JSON.stringify({ success: true, rawOutput: result }));
    }
}