const express = require("express");
const router  = require("express").Router();
const db      = require("../database/database");
const auth    = require("../middleware/auth");

/* ─────────────────────────────────────────
   HELPER: Timer sicherstellen
   Legt beim allerersten Aufruf einen
   Eintrag an – laeuft dann fuer immer durch.
   Wird NUR durch collect() zurueckgesetzt.
───────────────────────────────────────── */
async function ensureTimer(userBuildingId) {
  const [[existing]] = await db.query(
    "SELECT last_collected FROM building_collect_timer WHERE user_building_id = ?",
    [userBuildingId]
  );
  if (!existing) {
    await db.query(
      "INSERT INTO building_collect_timer (user_building_id, last_collected) VALUES (?, NOW())",
      [userBuildingId]
    );
  }
}

/* ─────────────────────────────────────────
   HELPER: Produktionsdaten laden
   Gibt immer last_collected aus der DB
───────────────────────────────────────── */
async function loadMineData(userId, buildingId) {
  const [rows] = await db.query(
    `
    SELECT
      ub.id              AS user_building_id,
      ub.level,
      bp.resource,
      bp.amount,
      bp.cycle_seconds,
      bct.last_collected
    FROM user_buildings ub
    JOIN building_production bp
      ON  bp.building_id = ub.building_id
      AND bp.level       = ub.level
    JOIN building_collect_timer bct
      ON  bct.user_building_id = ub.id
    WHERE ub.user_id     = ?
      AND ub.building_id = ?
    `,
    [userId, buildingId]
  );
  return rows;
}

/* ─────────────────────────────────────────
   GET /api/mine/:buildingId/status
───────────────────────────────────────── */
router.get("/:buildingId/status", auth, async (req, res) => {
  const userId     = req.session.user.id;
  const buildingId = req.params.buildingId;

  try {
    // user_building holen
    const [[userBuilding]] = await db.query(
      "SELECT id, level FROM user_buildings WHERE user_id = ? AND building_id = ?",
      [userId, buildingId]
    );

    if (!userBuilding) {
      return res.status(404).json({ error: "Gebaeude nicht gefunden" });
    }

    // Timer einmalig starten falls noch nie geoeffnet
    await ensureTimer(userBuilding.id);

    const rows = await loadMineData(userId, buildingId);
    if (!rows.length) {
      return res.status(404).json({ error: "Gebaeude nicht gefunden" });
    }

    const { cycle_seconds, last_collected, level } = rows[0];

    const elapsed = Math.floor((Date.now() - new Date(last_collected).getTime()) / 1000);
    const cycles  = Math.floor(elapsed / cycle_seconds);
    const nextIn  = cycle_seconds - (elapsed % cycle_seconds);

    const available = rows.map((r) => ({
      resource: r.resource,
      amount:   r.amount * cycles,
    }));

    const production = rows.map((r) => ({
      resource: r.resource,
      amount:   r.amount,
    }));

    res.json({
      level,
      cycles,
      ready:                 cycles > 0,
      available,
      production,
      last_collected,
      next_cycle_in_seconds: nextIn,
      cycle_seconds,
    });

  } catch (err) {
    console.error(err);
    res.status(500).json({ error: "DB Fehler" });
  }
});

/* ─────────────────────────────────────────
   POST /api/mine/:buildingId/collect
   Ressourcen gutschreiben + Timer reset
───────────────────────────────────────── */
router.post("/:buildingId/collect", auth, async (req, res) => {
  const userId     = req.session.user.id;
  const buildingId = req.params.buildingId;

  try {
    // user_building holen
    const [[userBuilding]] = await db.query(
      "SELECT id FROM user_buildings WHERE user_id = ? AND building_id = ?",
      [userId, buildingId]
    );

    if (!userBuilding) {
      return res.status(404).json({ error: "Gebaeude nicht gefunden" });
    }

    // Timer sicherstellen (Fallback falls Status nie aufgerufen wurde)
    await ensureTimer(userBuilding.id);

    const rows = await loadMineData(userId, buildingId);
    if (!rows.length) {
      return res.status(404).json({ error: "Gebaeude nicht gefunden" });
    }

    const { user_building_id, cycle_seconds, last_collected } = rows[0];

    const elapsed = Math.floor((Date.now() - new Date(last_collected).getTime()) / 1000);
    const cycles  = Math.floor(elapsed / cycle_seconds);

    if (cycles < 1) {
      const waitSeconds = cycle_seconds - elapsed;
      const minutes     = Math.floor(waitSeconds / 60);
      const seconds     = waitSeconds % 60;
      return res.json({
        error:            "Noch nichts bereit",
        ready_in_seconds: waitSeconds,
        ready_in_display: `${minutes}m ${seconds}s`,
      });
    }

    // ── Alle Ressourcen atomar in EINEM Query schreiben ──────────────
    // Verhindert inkonsistente Zustände bei Verbindungsabbrüchen
    const setClauses = rows
      .map((r) => `\`${r.resource}\` = \`${r.resource}\` + ${r.amount * cycles}`)
      .join(", ");

    await db.query(
      `INSERT INTO account_currency (account_id)
       VALUES (?)
       ON DUPLICATE KEY UPDATE ${setClauses}`,
      [userId]
    );

    // Timer zuruecksetzen: last_collected um genau die abgeschlossenen
    // Zyklen vorruecken – Restsekunden bleiben erhalten, kein Verlust
    const newLastCollected = new Date(
      new Date(last_collected).getTime() + cycles * cycle_seconds * 1000
    );

    await db.query(
      "UPDATE building_collect_timer SET last_collected = ? WHERE user_building_id = ?",
      [newLastCollected, user_building_id]
    );

    const collected = rows.map((r) => ({
      resource: r.resource,
      amount:   r.amount * cycles,
    }));

    res.json({ success: true, cycles, collected });

  } catch (err) {
    console.error(err);
    res.status(500).json({ error: "DB Fehler" });
  }
});

module.exports = router;