package sqlmock

import (
	"database/sql/driver"
	"reflect"
	"regexp"
	"sync"
)

// Argument interface allows to match
// any argument in specific way when used with
// ExpectedQuery and ExpectedExec expectations.
type Argument interface {
	Match(driver.Value) bool
}

// an expectation interface
type expectation interface {
	fulfilled() bool
	Lock()
	Unlock()
}

// common expectation struct
// satisfies the expectation interface
type commonExpectation struct {
	sync.Mutex
	triggered bool
	err       error
}

func (e *commonExpectation) fulfilled() bool {
	return e.triggered
}

// ExpectedClose is used to manage *sql.DB.Close expectation
// returned by *Sqlmock.ExpectClose.
type ExpectedClose struct {
	commonExpectation
}

// WillReturnError allows to set an error for *sql.DB.Close action
func (e *ExpectedClose) WillReturnError(err error) *ExpectedClose {
	e.err = err
	return e
}

// ExpectedBegin is used to manage *sql.DB.Begin expectation
// returned by *Sqlmock.ExpectBegin.
type ExpectedBegin struct {
	commonExpectation
}

// WillReturnError allows to set an error for *sql.DB.Begin action
func (e *ExpectedBegin) WillReturnError(err error) *ExpectedBegin {
	e.err = err
	return e
}

// ExpectedCommit is used to manage *sql.Tx.Commit expectation
// returned by *Sqlmock.ExpectCommit.
type ExpectedCommit struct {
	commonExpectation
}

// WillReturnError allows to set an error for *sql.Tx.Close action
func (e *ExpectedCommit) WillReturnError(err error) *ExpectedCommit {
	e.err = err
	return e
}

// ExpectedRollback is used to manage *sql.Tx.Rollback expectation
// returned by *Sqlmock.ExpectRollback.
type ExpectedRollback struct {
	commonExpectation
}

// WillReturnError allows to set an error for *sql.Tx.Rollback action
func (e *ExpectedRollback) WillReturnError(err error) *ExpectedRollback {
	e.err = err
	return e
}

// ExpectedQuery is used to manage *sql.DB.Query, *dql.DB.QueryRow, *sql.Tx.Query,
// *sql.Tx.QueryRow, *sql.Stmt.Query or *sql.Stmt.QueryRow expectations.
// Returned by *Sqlmock.ExpectQuery.
type ExpectedQuery struct {
	queryBasedExpectation
	rows driver.Rows
}

// WithArgs will match given expected args to actual database query arguments.
// if at least one argument does not match, it will return an error. For specific
// arguments an sqlmock.Argument interface can be used to match an argument.
func (e *ExpectedQuery) WithArgs(args ...driver.Value) *ExpectedQuery {
	e.args = args
	return e
}

// WillReturnError allows to set an error for expected database query
func (e *ExpectedQuery) WillReturnError(err error) *ExpectedQuery {
	e.err = err
	return e
}

// WillReturnRows specifies the set of resulting rows that will be returned
// by the triggered query
func (e *ExpectedQuery) WillReturnRows(rows driver.Rows) *ExpectedQuery {
	e.rows = rows
	return e
}

// ExpectedExec is used to manage *sql.DB.Exec, *sql.Tx.Exec or *sql.Stmt.Exec expectations.
// Returned by *Sqlmock.ExpectExec.
type ExpectedExec struct {
	queryBasedExpectation
	result driver.Result
}

// WithArgs will match given expected args to actual database exec operation arguments.
// if at least one argument does not match, it will return an error. For specific
// arguments an sqlmock.Argument interface can be used to match an argument.
func (e *ExpectedExec) WithArgs(args ...driver.Value) *ExpectedExec {
	e.args = args
	return e
}

// WillReturnError allows to set an error for expected database exec action
func (e *ExpectedExec) WillReturnError(err error) *ExpectedExec {
	e.err = err
	return e
}

// WillReturnResult arranges for an expected Exec() to return a particular
// result, there is sqlmock.NewResult(lastInsertID int64, affectedRows int64) method
// to build a corresponding result. Or if actions needs to be tested against errors
// sqlmock.NewErrorResult(err error) to return a given error.
func (e *ExpectedExec) WillReturnResult(result driver.Result) *ExpectedExec {
	e.result = result
	return e
}

// ExpectedPrepare is used to manage *sql.DB.Prepare or *sql.Tx.Prepare expectations.
// Returned by *Sqlmock.ExpectPrepare.
type ExpectedPrepare struct {
	commonExpectation
	mock      *Sqlmock
	sqlRegex  *regexp.Regexp
	statement driver.Stmt
	closeErr  error
}

// WillReturnError allows to set an error for the expected *sql.DB.Prepare or *sql.Tx.Prepare action.
func (e *ExpectedPrepare) WillReturnError(err error) *ExpectedPrepare {
	e.err = err
	return e
}

// WillReturnCloseError allows to set an error for this prapared statement Close action
func (e *ExpectedPrepare) WillReturnCloseError(err error) *ExpectedPrepare {
	e.closeErr = err
	return e
}

// ExpectQuery allows to expect Query() or QueryRow() on this prepared statement.
// this method is convenient in order to prevent duplicating sql query string matching.
func (e *ExpectedPrepare) ExpectQuery() *ExpectedQuery {
	eq := &ExpectedQuery{}
	eq.sqlRegex = e.sqlRegex
	e.mock.expected = append(e.mock.expected, eq)
	return eq
}

// ExpectExec allows to expect Exec() on this prepared statement.
// this method is convenient in order to prevent duplicating sql query string matching.
func (e *ExpectedPrepare) ExpectExec() *ExpectedExec {
	eq := &ExpectedExec{}
	eq.sqlRegex = e.sqlRegex
	e.mock.expected = append(e.mock.expected, eq)
	return eq
}

// query based expectation
// adds a query matching logic
type queryBasedExpectation struct {
	commonExpectation
	sqlRegex *regexp.Regexp
	args     []driver.Value
}

func (e *queryBasedExpectation) attemptMatch(sql string, args []driver.Value) (ret bool) {
	if !e.queryMatches(sql) {
		return
	}

	defer recover() // ignore panic since we attempt a match

	if e.argsMatches(args) {
		return true
	}
	return
}

func (e *queryBasedExpectation) queryMatches(sql string) bool {
	return e.sqlRegex.MatchString(sql)
}

func (e *queryBasedExpectation) argsMatches(args []driver.Value) bool {
	if nil == e.args {
		return true
	}
	if len(args) != len(e.args) {
		return false
	}
	for k, v := range args {
		matcher, ok := e.args[k].(Argument)
		if ok {
			if !matcher.Match(v) {
				return false
			}
			continue
		}
		vi := reflect.ValueOf(v)
		ai := reflect.ValueOf(e.args[k])
		switch vi.Kind() {
		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
			if vi.Int() != ai.Int() {
				return false
			}
		case reflect.Float32, reflect.Float64:
			if vi.Float() != ai.Float() {
				return false
			}
		case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
			if vi.Uint() != ai.Uint() {
				return false
			}
		case reflect.String:
			if vi.String() != ai.String() {
				return false
			}
		default:
			// compare types like time.Time based on type only
			if vi.Kind() != ai.Kind() {
				return false
			}
		}
	}
	return true
}