package repository

import (
	"context"
	"errors"

	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgxpool"

	"financeiro-carvalho/internal/middleware"
	"financeiro-carvalho/internal/model"
)

type CreditBillRepository interface {
	ListByAccount(ctx context.Context, accountID int) ([]model.CreditBill, error)
	GetCurrent(ctx context.Context, accountID int) (*model.CreditBill, error)
	Upsert(ctx context.Context, in model.CreditBillInput) (*model.CreditBill, error)
	MarkPaid(ctx context.Context, id int, paymentAccountID *int) error
}

type creditBillRepo struct{ db *pgxpool.Pool }

func NewCreditBillRepository(db *pgxpool.Pool) CreditBillRepository {
	return &creditBillRepo{db: db}
}

func (r *creditBillRepo) ListByAccount(ctx context.Context, accountID int) ([]model.CreditBill, error) {
	pid := middleware.ProfileIDFromCtx(ctx)
	rows, err := r.db.Query(ctx, `
		SELECT
			cb.id, cb.account_id, a.name,
			cb.period_start::text, cb.period_end::text, cb.due_date::text,
			COALESCE(SUM(t.amount) FILTER (WHERE t.type = 'expense'), 0) AS total,
			cb.paid, cb.paid_at::text, cb.payment_account_id
		FROM credit_bills cb
		JOIN accounts a ON a.id = cb.account_id AND a.profile_id = $2
		LEFT JOIN transactions t ON t.account_id = cb.account_id
			AND t.date >= cb.period_start AND t.date <= cb.period_end
			AND t.type = 'expense'
		WHERE cb.account_id = $1
		GROUP BY cb.id, a.name
		ORDER BY cb.period_start DESC
	`, accountID, pid)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var out []model.CreditBill
	for rows.Next() {
		var b model.CreditBill
		if err := rows.Scan(&b.ID, &b.AccountID, &b.AccountName, &b.PeriodStart, &b.PeriodEnd, &b.DueDate, &b.Total, &b.Paid, &b.PaidAt, &b.PaymentAccountID); err != nil {
			return nil, err
		}
		out = append(out, b)
	}
	return out, rows.Err()
}

func (r *creditBillRepo) GetCurrent(ctx context.Context, accountID int) (*model.CreditBill, error) {
	pid := middleware.ProfileIDFromCtx(ctx)
	var b model.CreditBill
	err := r.db.QueryRow(ctx, `
		SELECT
			cb.id, cb.account_id, a.name,
			cb.period_start::text, cb.period_end::text, cb.due_date::text,
			COALESCE(SUM(t.amount) FILTER (WHERE t.type = 'expense'), 0) AS total,
			cb.paid, cb.paid_at::text, cb.payment_account_id
		FROM credit_bills cb
		JOIN accounts a ON a.id = cb.account_id AND a.profile_id = $2
		LEFT JOIN transactions t ON t.account_id = cb.account_id
			AND t.date >= cb.period_start AND t.date <= cb.period_end
			AND t.type = 'expense'
		WHERE cb.account_id = $1 AND cb.paid = FALSE
		GROUP BY cb.id, a.name
		ORDER BY cb.period_start DESC
		LIMIT 1
	`, accountID, pid).Scan(&b.ID, &b.AccountID, &b.AccountName, &b.PeriodStart, &b.PeriodEnd, &b.DueDate, &b.Total, &b.Paid, &b.PaidAt, &b.PaymentAccountID)
	if errors.Is(err, pgx.ErrNoRows) {
		return nil, nil
	}
	return &b, err
}

func (r *creditBillRepo) Upsert(ctx context.Context, in model.CreditBillInput) (*model.CreditBill, error) {
	var b model.CreditBill
	err := r.db.QueryRow(ctx, `
		INSERT INTO credit_bills (account_id, period_start, period_end, due_date, payment_account_id)
		VALUES ($1, $2, $3, $4, $5)
		ON CONFLICT (account_id, period_start) DO UPDATE
			SET period_end = EXCLUDED.period_end,
			    due_date   = EXCLUDED.due_date,
			    payment_account_id = EXCLUDED.payment_account_id
		RETURNING id, account_id, period_start::text, period_end::text, due_date::text, paid, paid_at::text, payment_account_id
	`, in.AccountID, in.PeriodStart, in.PeriodEnd, in.DueDate, in.PaymentAccountID).
		Scan(&b.ID, &b.AccountID, &b.PeriodStart, &b.PeriodEnd, &b.DueDate, &b.Paid, &b.PaidAt, &b.PaymentAccountID)
	return &b, err
}

func (r *creditBillRepo) MarkPaid(ctx context.Context, id int, paymentAccountID *int) error {
	pid := middleware.ProfileIDFromCtx(ctx)
	_, err := r.db.Exec(ctx, `
		UPDATE credit_bills cb
		SET paid = TRUE, paid_at = NOW(), payment_account_id = $2
		FROM accounts a
		WHERE cb.id = $1 AND cb.account_id = a.id AND a.profile_id = $3
	`, id, paymentAccountID, pid)
	return err
}