/**
 * PayPal direct integration — capture, tracking, refund.
 *
 * POST /api/v1/paypal/capture          — Capture approved order (called from success page)
 * POST /api/v1/paypal/tracking         — Add tracking number to captured order
 * POST /api/v1/paypal/refund           — Refund a captured payment
 * GET  /api/v1/paypal/order/:id/status — Check PayPal order status
 */

import { Router, type Request, type Response } from "express";
import { pool } from "../db.js";
import { handlePaymentComplete } from "./checkout.js";

const router = Router();

// ─── PayPal API helpers ───────────────────────────────────────────────────────

const PAYPAL_API_URL      = process.env.PAYPAL_API_URL      || "https://api-m.paypal.com";
const PAYPAL_CLIENT_ID    = process.env.PAYPAL_CLIENT_ID    || "";
const PAYPAL_CLIENT_SECRET = process.env.PAYPAL_CLIENT_SECRET || "";

async function getAccessToken(): Promise<string> {
  const res = await fetch(`${PAYPAL_API_URL}/v1/oauth2/token`, {
    method: "POST",
    headers: {
      Authorization: `Basic ${Buffer.from(`${PAYPAL_CLIENT_ID}:${PAYPAL_CLIENT_SECRET}`).toString("base64")}`,
      "Content-Type": "application/x-www-form-urlencoded",
    },
    body: "grant_type=client_credentials",
  });
  const data = await res.json() as { access_token?: string; error?: string };
  if (!data.access_token) throw new Error(`PayPal auth failed: ${data.error || "no access_token"}`);
  return data.access_token;
}

async function paypalFetch(method: string, path: string, body?: object): Promise<{ status: number; data: any }> {
  const token = await getAccessToken();
  const res = await fetch(`${PAYPAL_API_URL}${path}`, {
    method,
    headers: {
      Authorization: `Bearer ${token}`,
      "Content-Type": "application/json",
    },
    ...(body ? { body: JSON.stringify(body) } : {}),
  });
  const data = await res.json().catch(() => ({}));
  return { status: res.status, data };
}

// ─── Capture an approved PayPal order ─────────────────────────────────────────
// Called when the buyer is redirected back after approving payment on PayPal.

router.post("/api/v1/paypal/capture", async (req: Request, res: Response) => {
  try {
    const { paypal_order_id, order_id, order_type } = req.body as {
      paypal_order_id?: string;
      order_id?: string;
      order_type?: string;
    };

    if (!paypal_order_id) {
      res.status(400).json({ error: "paypal_order_id required" });
      return;
    }

    const { status, data } = await paypalFetch("POST", `/v2/checkout/orders/${paypal_order_id}/capture`);

    if (status >= 400) {
      console.error("[paypal] Capture failed:", data);
      // If already captured, treat as success
      if (data?.details?.[0]?.issue === "ORDER_ALREADY_CAPTURED") {
        const check = await paypalFetch("GET", `/v2/checkout/orders/${paypal_order_id}`);
        if (check.data?.status === "COMPLETED") {
          res.json({ success: true, status: "COMPLETED", already_captured: true });
          return;
        }
      }
      res.status(502).json({ error: "PayPal capture failed", details: data });
      return;
    }

    if (data.status === "COMPLETED") {
      console.log(`[paypal] Captured ${paypal_order_id} successfully`);

      // Find the internal order and mark as paid
      const resolvedOrderId = order_id || data.purchase_units?.[0]?.custom_id || data.purchase_units?.[0]?.reference_id;
      // Infer order type from ID prefix if not provided
      let resolvedOrderType = order_type || "";
      if (!resolvedOrderType && resolvedOrderId) {
        if (resolvedOrderId.startsWith("CB-")) resolvedOrderType = "compliance_batch";
        else if (resolvedOrderId.startsWith("CO-")) resolvedOrderType = "compliance";
        else if (resolvedOrderId.startsWith("FO-")) resolvedOrderType = "formation";
        else resolvedOrderType = "canada_crtc";
      }

      if (resolvedOrderId) {
        try {
          // Store PayPal capture details in the order before marking paid
          const captureId = data.purchase_units?.[0]?.payments?.captures?.[0]?.id || "";
          const payerEmail = data.payer?.email_address || "";

          // Update the correct table with PayPal order ID
          const tableMap: Record<string, { table: string; col: string }> = {
            formation: { table: "formation_orders", col: "order_number" },
            canada_crtc: { table: "canada_crtc_orders", col: "order_number" },
            compliance: { table: "compliance_orders", col: "order_number" },
            compliance_batch: { table: "compliance_orders", col: "batch_id" },
          };
          const target = tableMap[resolvedOrderType] || tableMap.canada_crtc;
          await pool.query(
            `UPDATE ${target.table} SET paypal_order_id = $1, payment_method = 'paypal' WHERE ${target.col} = $2`,
            [paypal_order_id, resolvedOrderId],
          ).catch((err: any) => console.error("[paypal] DB update failed:", err.message));

          await handlePaymentComplete(resolvedOrderId, resolvedOrderType, `paypal-${captureId}`);
        } catch (err) {
          console.error("[paypal] handlePaymentComplete failed (non-blocking):", err);
        }
      }

      res.json({
        success: true,
        status: "COMPLETED",
        capture_id: data.purchase_units?.[0]?.payments?.captures?.[0]?.id,
        payer_email: data.payer?.email_address,
      });
    } else {
      res.json({ success: false, status: data.status, details: data });
    }
  } catch (err: any) {
    console.error("[paypal] Capture error:", err);
    res.status(500).json({ error: err.message || "PayPal capture failed" });
  }
});

// ─── Check PayPal order status ────────────────────────────────────────────────

router.get("/api/v1/paypal/order/:id/status", async (req: Request, res: Response) => {
  try {
    const { id } = req.params;
    const { status, data } = await paypalFetch("GET", `/v2/checkout/orders/${id}`);
    if (status >= 400) {
      res.status(status).json({ error: "PayPal order lookup failed", details: data });
      return;
    }
    res.json({
      paypal_order_id: data.id,
      status: data.status,
      payer_email: data.payer?.email_address,
      amount: data.purchase_units?.[0]?.amount,
      custom_id: data.purchase_units?.[0]?.custom_id,
    });
  } catch (err: any) {
    console.error("[paypal] Status check error:", err);
    res.status(500).json({ error: err.message });
  }
});

// ─── Add tracking number to a captured order ──────────────────────────────────

router.post("/api/v1/paypal/tracking", async (req: Request, res: Response) => {
  try {
    const { capture_id, tracking_number, carrier, order_id } = req.body as {
      capture_id?: string;
      tracking_number?: string;
      carrier?: string;
      order_id?: string;
    };

    if (!capture_id || !tracking_number) {
      res.status(400).json({ error: "capture_id and tracking_number required" });
      return;
    }

    // PayPal tracking API — POST /v1/shipping/trackers-batch
    const { status, data } = await paypalFetch("POST", "/v1/shipping/trackers-batch", {
      trackers: [{
        transaction_id: capture_id,
        tracking_number,
        status: "SHIPPED",
        carrier: carrier || "OTHER",
      }],
    });

    if (status >= 400) {
      console.error("[paypal] Tracking update failed:", data);
      res.status(502).json({ error: "PayPal tracking update failed", details: data });
      return;
    }

    console.log(`[paypal] Tracking added for capture ${capture_id}: ${tracking_number}`);
    res.json({ success: true, tracking_number, capture_id });
  } catch (err: any) {
    console.error("[paypal] Tracking error:", err);
    res.status(500).json({ error: err.message });
  }
});

// ─── Refund a captured payment ────────────────────────────────────────────────

router.post("/api/v1/paypal/refund", async (req: Request, res: Response) => {
  try {
    const { capture_id, amount, currency, reason, order_id } = req.body as {
      capture_id?: string;
      amount?: string;
      currency?: string;
      reason?: string;
      order_id?: string;
    };

    if (!capture_id) {
      res.status(400).json({ error: "capture_id required" });
      return;
    }

    const refundBody: Record<string, any> = {};
    if (amount) {
      refundBody.amount = { value: amount, currency_code: currency || "USD" };
    }
    if (reason) {
      refundBody.note_to_payer = reason;
    }

    const { status, data } = await paypalFetch(
      "POST",
      `/v2/payments/captures/${capture_id}/refund`,
      Object.keys(refundBody).length > 0 ? refundBody : undefined,
    );

    if (status >= 400) {
      console.error("[paypal] Refund failed:", data);
      res.status(502).json({ error: "PayPal refund failed", details: data });
      return;
    }

    console.log(`[paypal] Refund ${data.id} for capture ${capture_id}: ${data.status}`);

    // Update order status if order_id provided
    if (order_id) {
      await pool.query(
        `UPDATE canada_crtc_orders SET payment_status = 'refunded' WHERE order_number = $1`,
        [order_id],
      ).catch(() => {});
      await pool.query(
        `UPDATE formation_orders SET payment_status = 'refunded' WHERE order_number = $1`,
        [order_id],
      ).catch(() => {});
    }

    res.json({
      success: true,
      refund_id: data.id,
      status: data.status,
      amount: data.amount,
    });
  } catch (err: any) {
    console.error("[paypal] Refund error:", err);
    res.status(500).json({ error: err.message });
  }
});

export default router;