import { app, HttpRequest, HttpResponseInit, InvocationContext } from "@azure/functions";
import { OTLPTraceExporter } from '@opentelemetry/exporter-trace-otlp-http';
import { NodeTracerProvider } from '@opentelemetry/sdk-trace-node';
import { SimpleSpanProcessor } from '@opentelemetry/sdk-trace-node';
import { resourceFromAttributes } from '@opentelemetry/resources';
import { SpanStatusCode } from '@opentelemetry/api';

// ====================== USER CONFIGURATION - EDIT THESE VALUES ======================
const config = {
    sensorId: '',
    
    collectorUrl: '', // example: https?://collector-domain:4318/v1/traces
    exporterSettings: {
        timeoutMillis: 3000,
    },
};
// ====================== END USER CONFIGURATION ====================================

// OpenTelemetry Setup
const setupTelemetry = () => {
    console.log('Starting OpenTelemetry setup...');
    const resource = resourceFromAttributes({
        'sensor.id': config.sensorId,
        'sensor.version': '1.0.0',  
        'service.name': 'astra-otel-plugin'  
    });

    const traceExporter = new OTLPTraceExporter({
        url: config.collectorUrl,
        timeoutMillis: config.exporterSettings.timeoutMillis
    });

    const provider = new NodeTracerProvider({
        resource: resource,
        spanProcessors: [new SimpleSpanProcessor(traceExporter as any)]
    });

    provider.register();
    return provider.getTracer('astra-otel-plugin');
};

const tracer = setupTelemetry();

// Telemetry wrapper function
const withTelemetry = async (
    request: HttpRequest, 
    statusCode: number,
    responseHeaders: Record<string, string>,
    responseBody: any
) => {
    const span = tracer.startSpan('http_trigger');
    
    try {
        // Get request headers and body
        const headers = Object.fromEntries(request.headers.entries());
        const body = await request.text().catch(() => '');
        const url = new URL(request.url);
        const target = url.pathname + url.search;

        // Get client IP address from headers
        const clientIp = request.headers.get('x-forwarded-for') || 
                        request.headers.get('x-real-ip') || 
                        '';

        // Set request span attributes
        span.setAttribute('http.method', request.method);
        span.setAttribute('http.status_code', statusCode);
        span.setAttribute('http.target', target);
        span.setAttribute('http.host', url.host);
        span.setAttribute('http.flavor', '1.1');
        span.setAttribute('http.scheme', url.protocol.replace(':', ''));
        span.setAttribute('http.request.headers', JSON.stringify(headers));
        span.setAttribute('http.request.body', body);
        span.setAttribute('net.sock.peer.addr', clientIp);
        
        // Set response span attributes
        span.setAttribute('http.response.headers', JSON.stringify(responseHeaders));
        span.setAttribute('http.response.body', JSON.stringify(responseBody));
        span.setStatus({ code: SpanStatusCode.OK });
    } catch (error) {
        span.setStatus({
            code: SpanStatusCode.ERROR,
            message: error instanceof Error ? error.message : 'Unknown error'
        });
        throw error;
    } finally {
        span.end();
    }
};

app.http('httpTrigger1', {
    methods: ['GET', 'POST'],
    authLevel: 'anonymous',
    handler: async (request: HttpRequest, context: InvocationContext): Promise<HttpResponseInit> => {

        // First, execute business logic and get response

        const responseBody = {
            // 'message': 'ok'
        }
        const statusCode = 200;
        const responseHeaders = {
            // 'content-type': 'application/json',
            // 'x-custom-header': 'custom-value'
        };

        // Start telemetry operations without awaiting them
        withTelemetry(
            request, 
            statusCode,
            responseHeaders,
            responseBody
        ).catch(error => console.error('Telemetry error:', error));

        // return response to user
        return {
            status: statusCode,
            headers: responseHeaders,
            body: JSON.stringify(responseBody)
        };
    }
});