import { NextRequest, NextResponse } from "next/server";
import { getCurrentUser } from "@/lib/auth";
import { queryRaw } from "@/lib/db";

export async function GET(req: NextRequest) {
  const user = await getCurrentUser(req);
  if (!user) return NextResponse.json({ error: "Unauthorized" }, { status: 403 });

  // Statement-level fees and interest (aggregated by Gemini from the PDF)
  const stmtRows = await queryRaw<{
    bank_name: string;
    fees: string;
    interest: string;
  }>(
    `SELECT
      bank_name,
      SUM(COALESCE(fees_charged, 0))::numeric(12,2) AS fees,
      SUM(COALESCE(interest_charged, 0))::numeric(12,2) AS interest
    FROM statements
    WHERE owner_id = $1
    GROUP BY bank_name
    HAVING SUM(COALESCE(fees_charged, 0)) + SUM(COALESCE(interest_charged, 0)) > 0
    ORDER BY (SUM(COALESCE(fees_charged, 0)) + SUM(COALESCE(interest_charged, 0))) DESC`,
    [user.id]
  );

  // Transaction-level fee and interest line items (split-adjusted)
  const txnRows = await queryRaw<{
    id: number;
    transaction_date: string;
    description: string;
    merchant_name: string | null;
    transaction_type: string;
    my_amount: string;
    bank_name: string;
  }>(
    `SELECT
      t.id,
      t.transaction_date,
      t.description,
      t.merchant_name,
      t.transaction_type,
      CASE
        WHEN ts.share_percent IS NOT NULL THEN COALESCE(t.amount_aud, t.amount) * ts.share_percent / 100
        ELSE COALESCE(t.amount_aud, t.amount)
      END::numeric(12,2) AS my_amount,
      s.bank_name
    FROM transactions t
    LEFT JOIN transaction_splits ts ON ts.transaction_id = t.id AND ts.participant_id = $1
    JOIN statements s ON s.id = t.statement_id
    WHERE s.owner_id = $1
      AND t.transaction_type IN ('fee', 'interest')
    ORDER BY t.transaction_date DESC`,
    [user.id]
  );

  const by_bank = stmtRows.map((r) => ({
    bank_name: r.bank_name,
    fees: Number(r.fees),
    interest: Number(r.interest),
    total: Number(r.fees) + Number(r.interest),
  }));

  const transactions = txnRows.map((r) => ({
    ...r,
    my_amount: Number(r.my_amount),
  }));

  // Totals from statement-level data (more complete — Gemini reads the statement summary)
  const total_fees = by_bank.reduce((s, r) => s + r.fees, 0);
  const total_interest = by_bank.reduce((s, r) => s + r.interest, 0);

  return NextResponse.json({ by_bank, transactions, total_fees, total_interest });
}