package dal

import (
	"database/sql"
	"errors"
	"fmt"
	"log"
	"os"

	"git.rosemyrtle.work/personal-finance/server/internal/entities"

	_ "github.com/jackc/pgx/v5/stdlib"
)

type Connection struct {
	db *sql.DB
}

func Open(credentials *entities.Credentials) (*Connection, error) {
	if credentials == nil {
		return nil, errors.New("missing credentials")
	}

	db, err := sql.Open("pgx", credentials.Database)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Unable to connect to database: %v\n", err)
		return nil, err
	}

	if err := db.Ping(); err != nil {
		log.Fatal(err)
	}

	return &Connection{db}, nil
}

func (c *Connection) Close() {
	c.db.Close()
}

func (conn *Connection) Transactions() []entities.Transaction {
	q := "SELECT t.date, t.description, t.amount FROM transactions t;"

	rows, err := conn.db.Query(q)
	if err != nil {
		log.Fatal(err)
	}

	var result []entities.Transaction

	for rows.Next() {
		var t entities.Transaction
		if err := rows.Scan(&t.Date, &t.Description, &t.Value); err != nil {
			log.Fatal(err)
		}
		result = append(result, t)
	}

	return result
}