package stardb

import (
	"context"
	"database/sql"
	"errors"
)

// StarTx represents a database transaction
type StarTx struct {
	tx *sql.Tx
	db *StarDB
}

// Query executes a query within the transaction
func (t *StarTx) Query(query string, args ...interface{}) (*StarRows, error) {
	return t.query(nil, query, args...)
}

// QueryContext executes a query with context within the transaction
func (t *StarTx) QueryContext(ctx context.Context, query string, args ...interface{}) (*StarRows, error) {
	return t.query(ctx, query, args...)
}

// query is the internal query implementation
func (t *StarTx) query(ctx context.Context, query string, args ...interface{}) (*StarRows, error) {
	if err := t.db.Ping(); err != nil {
		return nil, err
	}

	var rows *sql.Rows
	var err error

	if ctx == nil {
		rows, err = t.tx.Query(query, args...)
	} else {
		rows, err = t.tx.QueryContext(ctx, query, args...)
	}

	if err != nil {
		return nil, err
	}

	starRows := &StarRows{
		rows: rows,
		db:   t.db,
	}

	if !t.db.ManualScan {
		err = starRows.parse()
	}

	return starRows, err
}

// Exec executes a query within the transaction
func (t *StarTx) Exec(query string, args ...interface{}) (sql.Result, error) {
	return t.exec(nil, query, args...)
}

// ExecContext executes a query with context within the transaction
func (t *StarTx) ExecContext(ctx context.Context, query string, args ...interface{}) (sql.Result, error) {
	return t.exec(ctx, query, args...)
}

// exec is the internal exec implementation
func (t *StarTx) exec(ctx context.Context, query string, args ...interface{}) (sql.Result, error) {
	if err := t.db.Ping(); err != nil {
		return nil, err
	}

	if ctx == nil {
		return t.tx.Exec(query, args...)
	}
	return t.tx.ExecContext(ctx, query, args...)
}

// Prepare creates a prepared statement within the transaction
func (t *StarTx) Prepare(query string) (*StarStmt, error) {
	stmt, err := t.tx.Prepare(query)
	if err != nil {
		return nil, err
	}
	return &StarStmt{stmt: stmt, db: t.db}, nil
}

// PrepareContext creates a prepared statement with context
func (t *StarTx) PrepareContext(ctx context.Context, query string) (*StarStmt, error) {
	stmt, err := t.tx.PrepareContext(ctx, query)
	if err != nil {
		return nil, err
	}
	return &StarStmt{stmt: stmt, db: t.db}, nil
}

// QueryStmt executes a prepared statement query within the transaction
func (t *StarTx) QueryStmt(query string, args ...interface{}) (*StarRows, error) {
	if query == "" {
		return nil, errors.New("query string cannot be empty")
	}
	stmt, err := t.Prepare(query)
	if err != nil {
		return nil, err
	}
	defer stmt.Close()
	return stmt.Query(args...)
}

// QueryStmtContext executes a prepared statement query with context
func (t *StarTx) QueryStmtContext(ctx context.Context, query string, args ...interface{}) (*StarRows, error) {
	if query == "" {
		return nil, errors.New("query string cannot be empty")
	}
	stmt, err := t.PrepareContext(ctx, query)
	if err != nil {
		return nil, err
	}
	defer stmt.Close()
	return stmt.QueryContext(ctx, args...)
}

// ExecStmt executes a prepared statement within the transaction
func (t *StarTx) ExecStmt(query string, args ...interface{}) (sql.Result, error) {
	if query == "" {
		return nil, errors.New("query string cannot be empty")
	}
	stmt, err := t.Prepare(query)
	if err != nil {
		return nil, err
	}
	defer stmt.Close()
	return stmt.Exec(args...)
}

// ExecStmtContext executes a prepared statement with context
func (t *StarTx) ExecStmtContext(ctx context.Context, query string, args ...interface{}) (sql.Result, error) {
	if query == "" {
		return nil, errors.New("query string cannot be empty")
	}
	stmt, err := t.PrepareContext(ctx, query)
	if err != nil {
		return nil, err
	}
	defer stmt.Close()
	return stmt.ExecContext(ctx, args...)
}

// Commit commits the transaction
func (t *StarTx) Commit() error {
	return t.tx.Commit()
}

// Rollback rolls back the transaction
func (t *StarTx) Rollback() error {
	return t.tx.Rollback()
}