package expense

import (
	"context"
	"fmt"
	"time"

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

type Expense struct {
	ID          string    `json:"id"`
	VehicleID   *string   `json:"vehicle_id"`
	Type        string    `json:"type"`
	Amount      float64   `json:"amount"`
	Description string    `json:"description"`
	Date        time.Time `json:"date"`
	CreatedAt   time.Time `json:"created_at"`
}

func ListExpenses(ctx context.Context, conn *pgxpool.Conn, typeFilter string) ([]*Expense, error) {
	q := `SELECT id, vehicle_id, type, amount, COALESCE(description,''), date, created_at
	      FROM expenses`
	args := []any{}
	if typeFilter != "" {
		q += " WHERE type = $1"
		args = append(args, typeFilter)
	}
	q += " ORDER BY date DESC, created_at DESC"
	rows, err := conn.Query(ctx, q, args...)
	if err != nil {
		return nil, fmt.Errorf("expense: list: %w", err)
	}
	defer rows.Close()
	var list []*Expense
	for rows.Next() {
		var e Expense
		if err := rows.Scan(&e.ID, &e.VehicleID, &e.Type, &e.Amount, &e.Description, &e.Date, &e.CreatedAt); err != nil {
			return nil, fmt.Errorf("expense: scan: %w", err)
		}
		list = append(list, &e)
	}
	return list, rows.Err()
}

func CreateExpense(ctx context.Context, conn *pgxpool.Conn, vehicleID *string, expType, description string, amount float64, date time.Time) (*Expense, error) {
	row := conn.QueryRow(ctx,
		`INSERT INTO expenses (vehicle_id, type, amount, description, date)
		 VALUES ($1, $2, $3, NULLIF($4,''), $5)
		 RETURNING id, vehicle_id, type, amount, COALESCE(description,''), date, created_at`,
		vehicleID, expType, amount, description, date)
	var e Expense
	if err := row.Scan(&e.ID, &e.VehicleID, &e.Type, &e.Amount, &e.Description, &e.Date, &e.CreatedAt); err != nil {
		return nil, fmt.Errorf("expense: create: %w", err)
	}
	return &e, nil
}

func DeleteExpense(ctx context.Context, conn *pgxpool.Conn, id string) error {
	tag, err := conn.Exec(ctx, `DELETE FROM expenses WHERE id = $1`, id)
	if err != nil {
		return fmt.Errorf("expense: delete: %w", err)
	}
	if tag.RowsAffected() == 0 {
		return pgx.ErrNoRows
	}
	return nil
}