package repository

import (
	"context"
	"strings"

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

	"financeiro-carvalho/internal/model"
)

type TransactionRepository interface {
	IsDuplicate(ctx context.Context, date, description string, amount float64) (bool, error)
	IsExternalIDKnown(ctx context.Context, externalID string) (bool, error)
	BulkInsert(ctx context.Context, rows []model.ImportRow) (int, error)
	SaveImportLog(ctx context.Context, filename, format string, imported, duplicates, errors int) error
}

type transactionRepo struct{ db *pgxpool.Pool }

func NewTransactionRepository(db *pgxpool.Pool) TransactionRepository {
	return &transactionRepo{db: db}
}

// normalizeDesc lowercases and collapses whitespace for fuzzy dedup.
func normalizeDesc(s string) string {
	return strings.ToLower(strings.Join(strings.Fields(s), " "))
}

func (r *transactionRepo) IsDuplicate(ctx context.Context, date, description string, amount float64) (bool, error) {
	var count int
	err := r.db.QueryRow(ctx, `
		SELECT COUNT(*) FROM transactions
		WHERE date = $1 AND amount = $2 AND LOWER(description) = $3`,
		date, amount, normalizeDesc(description)).Scan(&count)
	return count > 0, err
}

func (r *transactionRepo) IsExternalIDKnown(ctx context.Context, externalID string) (bool, error) {
	if externalID == "" {
		return false, nil
	}
	var count int
	err := r.db.QueryRow(ctx, `
		SELECT COUNT(*) FROM transactions WHERE external_id = $1`, externalID).Scan(&count)
	return count > 0, err
}

func (r *transactionRepo) BulkInsert(ctx context.Context, rows []model.ImportRow) (int, error) {
	tx, err := r.db.Begin(ctx)
	if err != nil {
		return 0, err
	}
	defer tx.Rollback(ctx)

	count := 0
	for _, row := range rows {
		if row.IsDuplicate {
			continue
		}
		var extID *string
		if row.ExternalID != "" {
			extID = &row.ExternalID
		}
		_, err := tx.Exec(ctx, `
			INSERT INTO transactions (date, amount, description, type, source, external_id)
			VALUES ($1, $2, $3, $4, 'import', $5)`,
			row.Date, row.Amount, row.Description, row.Type, extID)
		if err != nil {
			return count, err
		}
		count++
	}
	return count, tx.Commit(ctx)
}

func (r *transactionRepo) SaveImportLog(ctx context.Context, filename, format string, imported, duplicates, errors int) error {
	_, err := r.db.Exec(ctx, `
		INSERT INTO import_logs (filename, format, imported_count, duplicate_count, error_count)
		VALUES ($1, $2, $3, $4, $5)`,
		filename, format, imported, duplicates, errors)
	return err
}