package dal

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

	"git.rosemyrtle.work/personal-finance/server/internal/entity"
)

type DalImpl struct {
	Db *sql.DB
}

func (dal *DalImpl) Transaction(transactionId int64) (*entity.Transaction, error) {
	log.Printf("DAL::Transaction(%v)", transactionId)

	if dal.Db == nil {
		log.Panic("database not available")
	}

	stmt := `
	SELECT t.id, t.date, t.description, t.amount, tc.name
	FROM pfbudget.transactions t
	LEFT JOIN pfbudget.transactions_categorized tc
	ON t.id = tc.id
	WHERE t.id = $1
	`

	rows, err := dal.Db.Query(stmt, transactionId)
	if err != nil {
		return nil, err
	}

	transactions := convert[entity.Transaction](rows)
	if len(transactions) == 0 {
		return nil, nil
	}

	return &transactions[0], nil
}

func (dal *DalImpl) Transactions(limit, offset int, category *string) (entity.Transactions, error) {
	log.Print("DAL::Transactions", "limit", limit, "offset", offset, "category", category)

	if dal.Db == nil {
		log.Panic("database not available")
	}

	stmt := `
	SELECT t.id, t.date, t.description, t.amount, tc.name
	FROM pfbudget.transactions t
	LEFT JOIN pfbudget.transactions_categorized tc
	ON t.id = tc.id`

	args := []any{limit, offset}

	if category != nil {
		stmt += `WHERE tc.name SIMILAR TO '%' || $3 || '%'`
		args = append(args, *category)
	}
	stmt += `
	ORDER BY t.date DESC
	LIMIT $1
	OFFSET $2`

	rows, err := dal.Db.Query(stmt, args...)
	if err != nil {
		return entity.Transactions{}, err
	}

	return convert[entity.Transaction](rows), nil
}

func (dal *DalImpl) InsertTransaction(t entity.Transaction) (entity.Transaction, error) {
	log.Print("DAL::InsertTransaction")

	if dal.Db == nil {
		log.Panic("database not available")
	}

	stmt := `
	INSERT INTO pfbudget.transactions (date, description, amount)
	VALUES ($1, $2, $3)
	RETURNING id
	`

	id := new(uint64)
	if err := dal.Db.QueryRow(stmt, t.Date, t.Description, t.Value).Scan(id); err != nil {
		return entity.Transaction{}, err
	}

	t.Id = *id
	return t, nil
}

func (dal *DalImpl) UpdateTransaction(id entity.TransactionId, category *entity.CategoryName) (bool, error) {
	log.Print("DAL::UpdateTransaction")

	if dal.Db == nil {
		log.Panic("database not available")
	}

	if category == nil {
		return false, errors.New("missing category")
	}

	// TODO(#31): build stmt from existing (!=nil) arguments
	stmt := `
	UPDATE pfbudget.transactions_categorized
	SET name = $2
	WHERE id = $1
	`

	result, err := dal.Db.Exec(stmt, id, *category)
	if err != nil {
		return false, err
	}

	nAffected, err := result.RowsAffected()
	if err != nil {
		return false, err
	}

	// TODO: find if this value can be different than 1, otherwise the func return can only be error
	if nAffected != 1 {
		return false, fmt.Errorf("%d rows affected", nAffected)
	}

	return true, nil
}

func (dal *DalImpl) TransactionExists(id uint64) (bool, error) {
	log.Print("DAL::TransactionExists")

	if dal.Db == nil {
		log.Panic("database not available")
	}

	stmt := `
	SELECT EXISTS(
		SELECT 1
		FROM pfbudget.transactions
		WHERE id = $1
	)
	`

	exists := new(bool)
	err := dal.Db.QueryRow(stmt, id).Scan(&exists)
	if err != nil {
		return false, err
	}

	return *exists, nil
}

func (dal *DalImpl) Bank(bankId string) (*entity.Bank, error) {
	log.Printf("DAL::Bank(%v)", bankId)

	if dal.Db == nil {
		log.Panic("database not available")
	}

	rows, err := dal.Db.Query("SELECT b.name, b.name, n.requisition_id FROM pfbudget.banks b JOIN pfbudget.banks_nordigen n ON b.name = n.name WHERE b.name = $1", bankId)
	if err != nil {
		return nil, err
	}

	banks := convert[entity.Bank](rows)
	if len(banks) == 0 {
		return nil, nil
	}

	return &banks[0], nil
}

func (dal *DalImpl) Banks() (entity.Banks, error) {
	log.Print("DAL::Banks")

	if dal.Db == nil {
		log.Panic("database not available")
	}

	rows, err := dal.Db.Query("SELECT b.name, b.name, n.requisition_id FROM pfbudget.banks b JOIN pfbudget.banks_nordigen n ON b.name = n.name")
	if err != nil {
		return entity.Banks{}, err
	}

	return convert[entity.Bank](rows), nil
}

func (dal *DalImpl) Categories() (entity.Categories, error) {
	log.Print("DAL::Categories")

	if dal.Db == nil {
		log.Panic("database not available")
	}

	rows, err := dal.Db.Query("SELECT c.name, c.group FROM pfbudget.categories c")
	if err != nil {
		return []entity.Category{}, err
	}

	return convert[entity.Category](rows), nil
}