import { createHash, randomInt } from "crypto";

import { sql } from "@/lib/db";
import { sendEmail } from "@/lib/mailer";

const hashCode = (email: string, code: string): string =>
  createHash("sha256").update(`${email}:${code}`).digest("hex");

export async function POST(req: Request) {
  const { email } = await req.json();

  if (!email?.trim()) {
    return Response.json({ error: "Email is required." }, { status: 400 });
  }

  const normalized = email.trim().toLowerCase();

  try {
    const users = await sql<{ id: string }>`
      SELECT id FROM users WHERE email = ${normalized}
    `;

    // Don't reveal whether the address is registered: always answer the same.
    if (!users[0]) {
      return Response.json({ data: { sent: false } });
    }

    const code = String(randomInt(0, 1_000_000)).padStart(6, "0");

    await sql`
      INSERT INTO password_reset_codes (email, code_hash, expires_at)
      VALUES (
        ${normalized},
        ${hashCode(normalized, code)},
        CURRENT_TIMESTAMP + INTERVAL '15 minutes'
      )
      ON CONFLICT (email) DO UPDATE SET
        code_hash = EXCLUDED.code_hash,
        expires_at = EXCLUDED.expires_at,
        attempts = 0
    `;

    const delivered = await sendEmail(
      normalized,
      "Reset your Waseel password",
      `We received a request to reset your Waseel password.\n\nYour reset code is: ${code}\n\nIt expires in 15 minutes. If you didn't ask for this, you can ignore this email.`,
    );

    return Response.json({
      data: {
        sent: delivered,
        // Without SMTP configured there is nothing to receive, so surface the
        // code to keep the reset flow usable on a self-hosted box.
        ...(delivered ? {} : { devCode: code }),
      },
    });
  } catch (error) {
    console.error("[FORGOT_PASSWORD]: ", error);
    return Response.json({ error: "Internal Server Error" }, { status: 500 });
  }
}