const express = require("express");
const cors = require("cors");
const jwt = require("jsonwebtoken");
require("dotenv").config();

const db = require("./db");

function log(level, message, meta = {}) {
  const timestamp = new Date().toISOString();
  console.log(JSON.stringify({ timestamp, level, service: "error_log_api", message, ...meta }));
}

async function ensureErrorLogTable() {
  try {
    await db.query(`CREATE SCHEMA IF NOT EXISTS data`);
    await db.query(`
      CREATE TABLE IF NOT EXISTS data.errors (
        id BIGSERIAL PRIMARY KEY,
        "date" TIMESTAMPTZ NOT NULL DEFAULT NOW(),
        "service" TEXT NOT NULL,
        partofservice TEXT,
        error TEXT NOT NULL
      )
    `);
    console.log("Error log table ready");
  } catch (err) {
    console.error("Failed to create error log table:", err);
  }
}

const app = express();
app.use(express.json({ limit: "64kb" }));
app.use(cors());

const ERROR_LOG_API_URL =
  process.env.ERROR_LOG_API_URL ||
  "https://error.xtransit.testinstance.nl/error_log";

function toFriendlyError(statusCode) {
  if (statusCode === 400) return "Controleer je invoer en probeer opnieuw.";
  if (statusCode === 401) return "Je sessie is verlopen. Log opnieuw in.";
  if (statusCode === 403) return "Je hebt hier geen toegang toe.";
  if (statusCode === 404) return "Niet gevonden.";
  return "Er ging iets mis. Probeer het later opnieuw.";
}

async function reportError({ partofservice, error }) {
  try {
    await fetch(ERROR_LOG_API_URL, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({
        service: "error_log_api",
        partofservice,
        error,
      }),
    });
  } catch (_) {}
}

app.use((req, res, next) => {
  const originalJson = res.json.bind(res);
  res.json = (body) => {
    if (res.statusCode >= 400 && body && typeof body === "object") {
      const rawError =
        body.error || body.message || body.details || `HTTP ${res.statusCode}`;
      log("warn", `HTTP ${res.statusCode}`, { path: req.originalUrl, method: req.method, error: rawError });
      void reportError({
        partofservice: `${req.method} ${req.originalUrl}`,
        error: rawError,
      });
      return originalJson({ error: toFriendlyError(res.statusCode) });
    }
    return originalJson(body);
  };

  next();
});

const PORT = Number(process.env.PORT || 5003);

function normalizeErrorText(value) {
  if (!value) return "Unknown error";
  if (typeof value === "string") return value;
  try {
    return JSON.stringify(value);
  } catch (_) {
    return String(value);
  }
}

async function insertErrorLog({
  service,
  partofservice,
  partOfService,
  error,
}) {
  const serviceName = String(service || "unknown_service").slice(0, 120);
  const part =
    partofservice || partOfService
      ? String(partofservice || partOfService).slice(0, 240)
      : null;
  const errorText = String(normalizeErrorText(error)).slice(0, 8000);

  await db.query(
    "INSERT INTO data.errors (service, partofservice, error) VALUES ($1, $2, $3)",
    [serviceName, part, errorText],
  );
}

function verifyAdmin(req, res, next) {
  const auth = req.headers.authorization;
  if (!auth || !auth.startsWith("Bearer ")) {
    log("warn", "Missing or invalid Authorization header", { path: req.originalUrl });
    return res.status(401).json({ error: toFriendlyError(401) });
  }

  try {
    const payload = jwt.verify(auth.slice(7), JWT_SECRET);
    if (!payload?.isAdmin) {
      log("warn", "Non-admin user attempted admin access", { userCode: payload?.userCode, path: req.originalUrl });
      return res.status(403).json({ error: toFriendlyError(403) });
    }

    req.user = payload;
    return next();
  } catch (err) {
    log("error", "JWT verification failed", { error: err.message, path: req.originalUrl });
    reportError({ partofservice: `verifyAdmin ${req.method} ${req.originalUrl}`, error: err.stack || err.message });
    return res.status(401).json({ error: toFriendlyError(401) });
  }
}

app.get("/health", async (_req, res) => {
  try {
    await db.query("SELECT 1");
    res.json({ status: "ok", service: "error_log_api", database: "ok" });
  } catch (err) {
    log("error", "Health check DB query failed", { error: err.message, stack: err.stack });
    reportError({ partofservice: "GET /health", error: err.stack || err.message });
    res.status(503).json({ status: "unavailable", service: "error_log_api" });
  }
});

app.post("/error_log", async (req, res) => {
  try {
    const service = req.body?.service;
    const partofservice =
      req.body?.partofservice || req.body?.partOfService || null;
    const error = req.body?.error;

    if (!service || !error) {
      log("warn", "Missing required fields in error_log", { body: req.body });
      return res.status(400).json({ error: toFriendlyError(400) });
    }

    await insertErrorLog({ service, partofservice, error });
    return res.status(201).json({ ok: true });
  } catch (err) {
    log("error", "POST /error_log failed", { error: err.message, stack: err.stack });
    reportError({ partofservice: "POST /error_log", error: err.stack || err.message });
    return res.status(500).json({ error: toFriendlyError(500) });
  }
});

app.get("/error_log", verifyAdmin, async (req, res) => {
  try {
    const limit = Math.min(Number(req.query.limit || 100), 500);
    const service = req.query.service ? String(req.query.service) : null;
    const partofservice =
      req.query.partofservice || req.query.partOfService
        ? String(req.query.partofservice || req.query.partOfService)
        : null;

    const where = [];
    const params = [];

    if (service) {
      params.push(service);
      where.push(`"service" = $${params.length}`);
    }
    if (partofservice) {
      params.push(partofservice);
      where.push(`partofservice ILIKE $${params.length}`);
      params[params.length - 1] = `%${partofservice}%`;
    }

    params.push(limit);
    const rows = await db.query(
      `SELECT id, date, service, partofservice, error
       FROM data.errors
       ${where.length ? `WHERE ${where.join(" AND ")}` : ""}
       ORDER BY "date" DESC, id DESC
       LIMIT $${params.length}`,
      params,
    );

    return res.json({ errors: rows.rows });
  } catch (err) {
    log("error", "GET /error_log failed", { error: err.message, stack: err.stack });
    reportError({ partofservice: "GET /error_log", error: err.stack || err.message });
    return res.status(500).json({ error: toFriendlyError(500) });
  }
});

app.use(async (err, req, res, _next) => {
  log("error", "Unhandled error", { error: err?.message, stack: err?.stack, path: req.originalUrl });
  try {
    await insertErrorLog({
      service: "error_log_api",
      partofservice: `${req.method} ${req.originalUrl}`,
      error: err?.stack || err?.message || String(err),
    });
  } catch (logErr) {
    log("error", "Failed to log internal error", { error: logErr.message });
  }

  if (res.headersSent) return;
  return res.status(500).json({ error: toFriendlyError(500) });
});

app.listen(PORT, async () => {
  await ensureErrorLogTable();
  console.log(`Error Log API listening on ${PORT}`);
});

module.exports = app;