/*
Package sqlmock is a mock library implementing sql driver. Which has one and only
purpose - to simulate any sql driver behavior in tests, without needing a real
database connection. It helps to maintain correct **TDD** workflow.

It does not require any modifications to your source code in order to test
and mock database operations. Supports concurrency and multiple database mocking.

The driver allows to mock any sql driver method behavior.
*/
package sqlmock

import (
	"database/sql"
	"database/sql/driver"
	"fmt"
	"time"
)

// Sqlmock interface serves to create expectations
// for any kind of database action in order to mock
// and test real database behavior.
type Sqlmock interface {
	// ExpectClose queues an expectation for this database
	// action to be triggered. the *ExpectedClose allows
	// to mock database response
	ExpectClose() *ExpectedClose

	// ExpectationsWereMet checks whether all queued expectations
	// were met in order. If any of them was not met - an error is returned.
	ExpectationsWereMet() error

	// ExpectPrepare expects Prepare() to be called with expectedSQL query.
	// the *ExpectedPrepare allows to mock database response.
	// Note that you may expect Query() or Exec() on the *ExpectedPrepare
	// statement to prevent repeating expectedSQL
	ExpectPrepare(expectedSQL string) *ExpectedPrepare

	// ExpectQuery expects Query() or QueryRow() to be called with expectedSQL query.
	// the *ExpectedQuery allows to mock database response.
	ExpectQuery(expectedSQL string) *ExpectedQuery

	// ExpectExec expects Exec() to be called with expectedSQL query.
	// the *ExpectedExec allows to mock database response
	ExpectExec(expectedSQL string) *ExpectedExec

	// ExpectBegin expects *sql.DB.Begin to be called.
	// the *ExpectedBegin allows to mock database response
	ExpectBegin() *ExpectedBegin

	// ExpectCommit expects *sql.Tx.Commit to be called.
	// the *ExpectedCommit allows to mock database response
	ExpectCommit() *ExpectedCommit

	// ExpectRollback expects *sql.Tx.Rollback to be called.
	// the *ExpectedRollback allows to mock database response
	ExpectRollback() *ExpectedRollback

	// ExpectPing expected *sql.DB.Ping to be called.
	// the *ExpectedPing allows to mock database response
	//
	// Ping support only exists in the SQL library in Go 1.8 and above.
	// ExpectPing in Go <=1.7 will return an ExpectedPing but not register
	// any expectations.
	//
	// You must enable pings using MonitorPingsOption for this to register
	// any expectations.
	ExpectPing() *ExpectedPing

	// MatchExpectationsInOrder gives an option whether to match all
	// expectations in the order they were set or not.
	//
	// By default it is set to - true. But if you use goroutines
	// to parallelize your query executation, that option may
	// be handy.
	//
	// This option may be turned on anytime during tests. As soon
	// as it is switched to false, expectations will be matched
	// in any order. Or otherwise if switched to true, any unmatched
	// expectations will be expected in order
	MatchExpectationsInOrder(bool)

	// NewRows allows Rows to be created from a
	// sql driver.Value slice or from the CSV string and
	// to be used as sql driver.Rows.
	NewRows(columns []string) *Rows
}

type sqlmock struct {
	ordered      bool
	dsn          string
	opened       int
	drv          *mockDriver
	converter    driver.ValueConverter
	queryMatcher QueryMatcher
	monitorPings bool

	expected []expectation
}

func (c *sqlmock) open(options []func(*sqlmock) error) (*sql.DB, Sqlmock, error) {
	db, err := sql.Open("sqlmock", c.dsn)
	if err != nil {
		return db, c, err
	}
	for _, option := range options {
		err := option(c)
		if err != nil {
			return db, c, err
		}
	}
	if c.converter == nil {
		c.converter = driver.DefaultParameterConverter
	}
	if c.queryMatcher == nil {
		c.queryMatcher = QueryMatcherRegexp
	}

	if c.monitorPings {
		// We call Ping on the driver shortly to verify startup assertions by
		// driving internal behaviour of the sql standard library. We don't
		// want this call to ping to be monitored for expectation purposes so
		// temporarily disable.
		c.monitorPings = false
		defer func() { c.monitorPings = true }()
	}
	return db, c, db.Ping()
}

func (c *sqlmock) ExpectClose() *ExpectedClose {
	e := &ExpectedClose{}
	c.expected = append(c.expected, e)
	return e
}

func (c *sqlmock) MatchExpectationsInOrder(b bool) {
	c.ordered = b
}

// Close a mock database driver connection. It may or may not
// be called depending on the circumstances, but if it is called
// there must be an *ExpectedClose expectation satisfied.
// meets http://golang.org/pkg/database/sql/driver/#Conn interface
func (c *sqlmock) Close() error {
	c.drv.Lock()
	defer c.drv.Unlock()

	c.opened--
	if c.opened == 0 {
		delete(c.drv.conns, c.dsn)
	}

	var expected *ExpectedClose
	var fulfilled int
	var ok bool
	for _, next := range c.expected {
		next.Lock()
		if next.fulfilled() {
			next.Unlock()
			fulfilled++
			continue
		}

		if expected, ok = next.(*ExpectedClose); ok {
			break
		}

		next.Unlock()
		if c.ordered {
			return fmt.Errorf("call to database Close, was not expected, next expectation is: %s", next)
		}
	}

	if expected == nil {
		msg := "call to database Close was not expected"
		if fulfilled == len(c.expected) {
			msg = "all expectations were already fulfilled, " + msg
		}
		return fmt.Errorf(msg)
	}

	expected.triggered = true
	expected.Unlock()
	return expected.err
}

func (c *sqlmock) ExpectationsWereMet() error {
	for _, e := range c.expected {
		e.Lock()
		fulfilled := e.fulfilled()
		e.Unlock()

		if !fulfilled {
			return fmt.Errorf("there is a remaining expectation which was not matched: %s", e)
		}

		// for expected prepared statement check whether it was closed if expected
		if prep, ok := e.(*ExpectedPrepare); ok {
			if prep.mustBeClosed && !prep.wasClosed {
				return fmt.Errorf("expected prepared statement to be closed, but it was not: %s", prep)
			}
		}

		// must check whether all expected queried rows are closed
		if query, ok := e.(*ExpectedQuery); ok {
			if query.rowsMustBeClosed && !query.rowsWereClosed {
				return fmt.Errorf("expected query rows to be closed, but it was not: %s", query)
			}
		}
	}
	return nil
}

// Begin meets http://golang.org/pkg/database/sql/driver/#Conn interface
func (c *sqlmock) Begin() (driver.Tx, error) {
	ex, err := c.begin()
	if ex != nil {
		time.Sleep(ex.delay)
	}
	if err != nil {
		return nil, err
	}

	return c, nil
}

func (c *sqlmock) begin() (*ExpectedBegin, error) {
	var expected *ExpectedBegin
	var ok bool
	var fulfilled int
	for _, next := range c.expected {
		next.Lock()
		if next.fulfilled() {
			next.Unlock()
			fulfilled++
			continue
		}

		if expected, ok = next.(*ExpectedBegin); ok {
			break
		}

		next.Unlock()
		if c.ordered {
			return nil, fmt.Errorf("call to database transaction Begin, was not expected, next expectation is: %s", next)
		}
	}
	if expected == nil {
		msg := "call to database transaction Begin was not expected"
		if fulfilled == len(c.expected) {
			msg = "all expectations were already fulfilled, " + msg
		}
		return nil, fmt.Errorf(msg)
	}

	expected.triggered = true
	expected.Unlock()

	return expected, expected.err
}

func (c *sqlmock) ExpectBegin() *ExpectedBegin {
	e := &ExpectedBegin{}
	c.expected = append(c.expected, e)
	return e
}

func (c *sqlmock) ExpectExec(expectedSQL string) *ExpectedExec {
	e := &ExpectedExec{}
	e.expectSQL = expectedSQL
	e.converter = c.converter
	c.expected = append(c.expected, e)
	return e
}

// Prepare meets http://golang.org/pkg/database/sql/driver/#Conn interface
func (c *sqlmock) Prepare(query string) (driver.Stmt, error) {
	ex, err := c.prepare(query)
	if ex != nil {
		time.Sleep(ex.delay)
	}
	if err != nil {
		return nil, err
	}

	return &statement{c, ex, query}, nil
}

func (c *sqlmock) prepare(query string) (*ExpectedPrepare, error) {
	var expected *ExpectedPrepare
	var fulfilled int
	var ok bool

	for _, next := range c.expected {
		next.Lock()
		if next.fulfilled() {
			next.Unlock()
			fulfilled++
			continue
		}

		if c.ordered {
			if expected, ok = next.(*ExpectedPrepare); ok {
				break
			}

			next.Unlock()
			return nil, fmt.Errorf("call to Prepare statement with query '%s', was not expected, next expectation is: %s", query, next)
		}

		if pr, ok := next.(*ExpectedPrepare); ok {
			if err := c.queryMatcher.Match(pr.expectSQL, query); err == nil {
				expected = pr
				break
			}
		}
		next.Unlock()
	}

	if expected == nil {
		msg := "call to Prepare '%s' query was not expected"
		if fulfilled == len(c.expected) {
			msg = "all expectations were already fulfilled, " + msg
		}
		return nil, fmt.Errorf(msg, query)
	}
	defer expected.Unlock()
	if err := c.queryMatcher.Match(expected.expectSQL, query); err != nil {
		return nil, fmt.Errorf("Prepare: %v", err)
	}

	expected.triggered = true
	return expected, expected.err
}

func (c *sqlmock) ExpectPrepare(expectedSQL string) *ExpectedPrepare {
	e := &ExpectedPrepare{expectSQL: expectedSQL, mock: c}
	c.expected = append(c.expected, e)
	return e
}

func (c *sqlmock) ExpectQuery(expectedSQL string) *ExpectedQuery {
	e := &ExpectedQuery{}
	e.expectSQL = expectedSQL
	e.converter = c.converter
	c.expected = append(c.expected, e)
	return e
}

func (c *sqlmock) ExpectCommit() *ExpectedCommit {
	e := &ExpectedCommit{}
	c.expected = append(c.expected, e)
	return e
}

func (c *sqlmock) ExpectRollback() *ExpectedRollback {
	e := &ExpectedRollback{}
	c.expected = append(c.expected, e)
	return e
}

// Commit meets http://golang.org/pkg/database/sql/driver/#Tx
func (c *sqlmock) Commit() error {
	var expected *ExpectedCommit
	var fulfilled int
	var ok bool
	for _, next := range c.expected {
		next.Lock()
		if next.fulfilled() {
			next.Unlock()
			fulfilled++
			continue
		}

		if expected, ok = next.(*ExpectedCommit); ok {
			break
		}

		next.Unlock()
		if c.ordered {
			return fmt.Errorf("call to Commit transaction, was not expected, next expectation is: %s", next)
		}
	}
	if expected == nil {
		msg := "call to Commit transaction was not expected"
		if fulfilled == len(c.expected) {
			msg = "all expectations were already fulfilled, " + msg
		}
		return fmt.Errorf(msg)
	}

	expected.triggered = true
	expected.Unlock()
	return expected.err
}

// Rollback meets http://golang.org/pkg/database/sql/driver/#Tx
func (c *sqlmock) Rollback() error {
	var expected *ExpectedRollback
	var fulfilled int
	var ok bool
	for _, next := range c.expected {
		next.Lock()
		if next.fulfilled() {
			next.Unlock()
			fulfilled++
			continue
		}

		if expected, ok = next.(*ExpectedRollback); ok {
			break
		}

		next.Unlock()
		if c.ordered {
			return fmt.Errorf("call to Rollback transaction, was not expected, next expectation is: %s", next)
		}
	}
	if expected == nil {
		msg := "call to Rollback transaction was not expected"
		if fulfilled == len(c.expected) {
			msg = "all expectations were already fulfilled, " + msg
		}
		return fmt.Errorf(msg)
	}

	expected.triggered = true
	expected.Unlock()
	return expected.err
}

// NewRows allows Rows to be created from a
// sql driver.Value slice or from the CSV string and
// to be used as sql driver.Rows.
func (c *sqlmock) NewRows(columns []string) *Rows {
	r := NewRows(columns)
	r.converter = c.converter
	return r
}