const express = require("express");
const bcrypt = require("bcryptjs");
const db = require("./db");
require("dotenv").config();

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

const app = express();
app.use(express.json());

app.use((req, res, next) => {
  res.setHeader("Access-Control-Allow-Origin", "*");
  res.setHeader("Access-Control-Allow-Methods", "GET,POST,OPTIONS");
  res.setHeader("Access-Control-Allow-Headers", "Content-Type, Authorization");
  if (req.method === "OPTIONS") return res.sendStatus(204);
  next();
});

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

function friendlyErrorMessage(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 {
    const response = await fetch(ERROR_LOG_API_URL, {
      method: "POST",
      headers: {
        "Content-Type": "application/json",
        "x-internal-api-key": process.env.INTERNAL_API_KEY || "",
      },
      body: JSON.stringify({
        service: "employee_api",
        partofservice,
        error,
      }),
    });
    if (!response.ok) {
      log("warn", "Error log forward failed", { status: response.status, partofservice });
    }
  } catch (err) {
    log("warn", "Error log forward failed", { error: err.message, partofservice });
  }
}

function reportUnhandled(context, err) {
  const message = err?.message || String(err);
  const stack = err?.stack || message;
  log("error", context, { error: message, stack });
  void reportError({ partofservice: context, error: stack });
}

process.on("uncaughtException", (err) => reportUnhandled("uncaughtException", err));
process.on("unhandledRejection", (reason) => reportUnhandled("unhandledRejection", reason));

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]
          .filter((v) => v !== undefined && v !== null && v !== "")
          .join(" - ") || `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: friendlyErrorMessage(res.statusCode) });
    }
    return originalJson(body);
  };

  next();
});

// Employee onboarding
app.post("/createemployee", async (req, res) => {
  try {
    const { firstname, lastname, job, password } = req.body;
    if (!firstname || !lastname || !job || !password) {
      log("warn", "Missing required fields in createemployee", { body: req.body });
      return res.status(400).json({
        error: "Firstname, Lastname, Job title and password are required",
      });
    }

    const resultCreateEmployee = await db.query(
      "INSERT INTO workers.employees (firstname, lastname, job) VALUES ($1, $2, $3) RETURNING id",
      [firstname, lastname, job],
    );
    const newEmployee = resultCreateEmployee.rows[0];
    const encryptedpassword = await bcrypt.hash(password, 12);
    const resultCreateUser = await db.query(
      "INSERT INTO workers.users (employee, password) VALUES ($1, $2) RETURNING usercode",
      [newEmployee.id, encryptedpassword],
    );
    const newUser = resultCreateUser.rows[0];
    log("info", "Employee created", { employeeId: newEmployee.id, userCode: newUser.usercode });
    return res
      .status(201)
      .json({ employee: firstname, code: newUser.usercode });
  } catch (err) {
    log("error", "Create employee error", { error: err.message, stack: err.stack });
    reportError({ partofservice: `${req.method} ${req.originalUrl}`, error: err.stack || err.message });
    res.status(500).json({ error: friendlyErrorMessage(500) });
  }
});

app.get("/health", async (_req, res) => {
  try {
    await db.query("SELECT 1");
    return res.status(200).json({ endpoint: "reachable", 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({ endpoint: "unreachable", database: "down" });
  }
});

const PORT = process.env.PORT || 4000;
app.listen(PORT, () => console.log(`Employee API listening on ${PORT}`));

module.exports = app;