package db_test

import (
	"log"
	"os"
	"testing"

	"git.bit5.ru/backend/db"
	"git.bit5.ru/backend/errors"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	"github.com/go-logr/stdr"
)

const verbosity = 0

var logger = stdr.New(log.New(os.Stdout, "", log.Lshortfile))

func getSettings() db.Settings {
	//TODO: use ENV settings as well
	stdr.SetVerbosity(verbosity)
	return db.Settings{Host: "127.0.0.1", Port: "3306", User: "root", Pass: "test", Name: "tests", Prefix: "tests"}
}

func getPool() *db.Pool {
	return db.OpenPool(getSettings())
}

func getDBC(p *db.Pool) *db.DBC {
	dbc := db.GetDBC(p, logger)
	return dbc
}

func TestDefaultClientCharsetAndCollation(t *testing.T) {
	p := getPool()
	dbc := getDBC(p)

	var result = make(map[string]string)

	characterSets, err := dbc.DB().Query("SHOW VARIABLES WHERE Variable_name in ('character_set_client', 'character_set_connection', 'character_set_results');")
	require.Nil(t, err)

	for characterSets.Next() {

		var variableName string
		var value string

		characterSets.Scan(&variableName, &value)

		result[variableName] = value
	}

	collations, err := dbc.DB().Query("show variables where Variable_name = 'collation_connection';")
	require.Nil(t, err)

	for collations.Next() {

		var variableName string
		var value string

		collations.Scan(&variableName, &value)

		result[variableName] = value
	}

	assert.Equal(t, "utf8", result["character_set_client"])
	assert.Equal(t, "utf8", result["character_set_connection"])
	assert.Equal(t, "utf8", result["character_set_results"])
	assert.Equal(t, "utf8_general_ci", result["collation_connection"])
}

func TestClientCharsetAndCollation(t *testing.T) {
	DSNWithLatinCollation := getSettings()
	DSNWithLatinCollation.Params = "?collation=latin1_swedish_ci"
	pool := db.OpenPool(DSNWithLatinCollation)
	defer pool.Close()

	var resultsLatin1 = make(map[string]string)

	dbLatin1 := db.GetDBC(pool, logger)

	characterSets, err := dbLatin1.DB().Query("show variables where Variable_name in ('character_set_client', 'character_set_connection', 'character_set_results');")
	require.Nil(t, err)

	for characterSets.Next() {
		var variableName string
		var value string

		characterSets.Scan(&variableName, &value)

		resultsLatin1[variableName] = value
	}

	collations, err := dbLatin1.DB().Query("show variables where Variable_name = 'collation_connection';")
	require.Nil(t, err)

	for collations.Next() {

		var variableName string
		var value string

		collations.Scan(&variableName, &value)

		resultsLatin1[variableName] = value
	}

	assert.Equal(t, "latin1", resultsLatin1["character_set_client"])
	assert.Equal(t, "latin1", resultsLatin1["character_set_connection"])
	assert.Equal(t, "latin1", resultsLatin1["character_set_results"])
	assert.Equal(t, "latin1_swedish_ci", resultsLatin1["collation_connection"])

}

func createFooTable(t *testing.T) {
	p := getPool()
	dbc := getDBC(p)
	defer p.Close()

	_, err := dbc.DB().Exec("DROP TABLE IF EXISTS foo")
	require.Nil(t, err)
	_, err = dbc.DB().Exec("CREATE TABLE IF NOT EXISTS foo(id int not null)")
	require.Nil(t, err)
}

func TestTransactionCommit(t *testing.T) {
	createFooTable(t)

	p := getPool()
	dbc := getDBC(p)
	defer p.Close()

	require.Nil(t, dbc.Begin())
	dbc.UpdateBySQL("INSERT INTO foo(id) VALUES(1),(2)").Exec()

	//let's try a fresh connection
	dbc1 := getDBC(p)
	assert.EqualValues(t, 0, countFoos(t, dbc1))

	assert.EqualValues(t, 2, countFoos(t, dbc))
	dbc.Commit()
	assert.EqualValues(t, 2, countFoos(t, dbc))

	//let's try a fresh connection
	dbc2 := getDBC(p)
	assert.EqualValues(t, 2, countFoos(t, dbc2))
}

func TestTransactionCommitNestedAllOk(t *testing.T) {
	createFooTable(t)

	p := getPool()
	dbc := getDBC(p)
	defer p.Close()
	//begin 1
	require.Nil(t, dbc.Begin())
	dbc.UpdateBySQL("INSERT INTO foo(id) VALUES(1),(2)").Exec()

	//let's try a fresh connection
	dbc1 := getDBC(p)
	assert.EqualValues(t, 0, countFoos(t, dbc1))

	//begin 2
	require.Nil(t, dbc.Begin())
	dbc.UpdateBySQL("INSERT INTO foo(id) VALUES(3)").Exec()
	//commit 2
	dbc.Commit()
	assert.EqualValues(t, 3, countFoos(t, dbc))

	//let's try a fresh connection
	dbc2 := getDBC(p)
	assert.EqualValues(t, 0, countFoos(t, dbc2))

	//commit 1
	dbc.Commit()
	assert.EqualValues(t, 3, countFoos(t, dbc))

	//let's try a fresh connection
	db3 := getDBC(p)
	assert.EqualValues(t, 3, countFoos(t, db3))
}

func TestTransactionCommitNestedRollback(t *testing.T) {
	createFooTable(t)

	p := getPool()
	dbc := getDBC(p)
	defer p.Close()
	//begin 1
	require.Nil(t, dbc.Begin())
	dbc.UpdateBySQL("INSERT INTO foo(id) VALUES(1),(2)").Exec()

	//let's try a fresh connection
	dbc1 := getDBC(p)
	assert.EqualValues(t, 0, countFoos(t, dbc1))

	//begin 2
	require.Nil(t, dbc.Begin())
	dbc.UpdateBySQL("INSERT INTO foo(id) VALUES(3)").Exec()
	//rollback 2
	dbc.Rollback()
	//rollback above doesn't have an effect since we are in the
	//nested transaction
	assert.EqualValues(t, 3, countFoos(t, dbc))

	//let's try a fresh connection
	dbc2 := getDBC(p)
	assert.EqualValues(t, 0, countFoos(t, dbc2))

	//rollback 1
	dbc.Rollback()
	assert.EqualValues(t, 0, countFoos(t, dbc))

	//let's try a fresh connection
	db3 := getDBC(p)
	assert.EqualValues(t, 0, countFoos(t, db3))
}

func TestTransactionRollbackOnDeferAllOK(t *testing.T) {
	createFooTable(t)

	p := getPool()
	dbc := getDBC(p)
	defer p.Close()

	fn := func() {
		dbc.Begin()
		defer dbc.RollbackOnDefer()
		dbc.UpdateBySQL("INSERT INTO foo(id) VALUES(1),(2)").Exec()
		assert.EqualValues(t, 2, countFoos(t, dbc))

		fnNested := func() {
			dbc.Begin()
			defer dbc.RollbackOnDefer()
			dbc.UpdateBySQL("INSERT INTO foo(id) VALUES(3)").Exec()
			assert.EqualValues(t, 3, countFoos(t, dbc))
			dbc.Commit()
		}

		fnNested()

		dbc.Commit()
	}

	fn()
	dbc1 := getDBC(p)
	assert.EqualValues(t, 3, countFoos(t, dbc1))
}

func TestTransactionRollbackOnDefer(t *testing.T) {
	createFooTable(t)

	p := getPool()
	dbc := getDBC(p)
	defer p.Close()

	fn := func() {
		dbc.Begin()
		defer dbc.RollbackOnDefer()
		dbc.UpdateBySQL("INSERT INTO foo(id) VALUES(1),(2)").Exec()
		assert.EqualValues(t, 2, countFoos(t, dbc))

		fnNested := func() {
			dbc.Begin()
			defer dbc.RollbackOnDefer()
			dbc.UpdateBySQL("INSERT INTO foo(id) VALUES(3)").Exec()
			assert.EqualValues(t, 3, countFoos(t, dbc))
			//commit is missing for some reason, emulating error
			//dbc.Commit()
		}

		fnNested()

		//commit is missing for some reason, emulating error
		//dbc.Commit()
	}

	fn()

	dbc1 := getDBC(p)
	assert.EqualValues(t, 0, countFoos(t, dbc1))
}

func TestTransaction(t *testing.T) {
	createFooTable(t)

	p := getPool()
	dbc := getDBC(p)
	defer p.Close()

	require.Nil(t, dbc.Transaction(func(dbs *db.DBC) error {
		dbs.UpdateBySQL("INSERT INTO foo(id) VALUES(1),(2)").Exec()

		//let's try a fresh connection
		dbc1 := getDBC(p)
		assert.EqualValues(t, 0, countFoos(t, dbc1))

		assert.EqualValues(t, 2, countFoos(t, dbc))
		return nil
	}))

	//let's try a fresh connection
	dbc2 := getDBC(p)
	assert.EqualValues(t, 2, countFoos(t, dbc2))
}

func TestTransactionRollbackOnError(t *testing.T) {
	createFooTable(t)

	p := getPool()
	dbc := getDBC(p)
	defer p.Close()

	err := dbc.Transaction(func(dbs *db.DBC) error {
		dbs.UpdateBySQL("INSERT INTO foo(id) VALUES(1),(2)").Exec()

		assert.EqualValues(t, 2, countFoos(t, dbc))
		return errors.New("Opps")
	})
	assert.EqualValues(t, "Opps", err.Error())

	//let's try a fresh connection
	dbc2 := getDBC(p)
	assert.EqualValues(t, 0, countFoos(t, dbc2))
}

func TestTransactionRollbackOnPanic(t *testing.T) {
	createFooTable(t)

	p := getPool()
	dbc := getDBC(p)
	defer p.Close()

	defer func() {
		if r := recover(); r != nil {
			str := r.(string)
			assert.EqualValues(t, str, "Ooops")

			//let's try a fresh connection
			dbc2 := getDBC(p)
			assert.EqualValues(t, 0, countFoos(t, dbc2))

		}
	}()

	dbc.Transaction(func(dbs *db.DBC) error {
		dbs.UpdateBySQL("INSERT INTO foo(id) VALUES(1),(2)").Exec()

		assert.EqualValues(t, 2, countFoos(t, dbc))
		panic("Ooops")
		return nil
	})
}

func countFoos(t *testing.T, dbc *db.DBC) int {
	var res int
	err := dbc.SelectBySQL("SELECT COUNT(id) FROM foo").LoadValue(&res)
	require.Nil(t, err)
	return res
}

func TestTransactionRollback(t *testing.T) {
	createFooTable(t)

	p := getPool()
	dbc := getDBC(p)
	defer p.Close()
	require.Nil(t, dbc.Begin())
	{
		_, err := dbc.UpdateBySQL("INSERT INTO foo(id) VALUES(1),(2)").Exec()
		require.Nil(t, err)
	}

	var res int
	{
		err := dbc.SelectBySQL("SELECT COUNT(id) FROM foo").LoadValue(&res)
		require.Nil(t, err)
		assert.EqualValues(t, 2, res)
	}
	dbc.Rollback()

	{
		err := dbc.SelectBySQL("SELECT COUNT(id) FROM foo").LoadValue(&res)
		require.Nil(t, err)
		assert.EqualValues(t, 0, res)
	}

	//let's try a fresh connection
	dbc2 := getDBC(p)
	{
		err := dbc2.SelectBySQL("SELECT COUNT(id) FROM foo").LoadValue(&res)
		require.Nil(t, err)
		assert.EqualValues(t, 0, res)
	}
}

func TestTransactionNestedRollback(t *testing.T) {
	createFooTable(t)

	p := getPool()
	dbc := getDBC(p)
	defer p.Close()
	//begin 1
	require.Nil(t, dbc.Begin())
	{
		_, err := dbc.UpdateBySQL("INSERT INTO foo(id) VALUES(1)").Exec()
		require.Nil(t, err)
	}

	var res int
	{
		err := dbc.SelectBySQL("SELECT COUNT(id) FROM foo").LoadValue(&res)
		require.Nil(t, err)
		assert.EqualValues(t, 1, res)
	}

	//begin 2
	require.Nil(t, dbc.Begin())
	{
		_, err := dbc.UpdateBySQL("INSERT INTO foo(id) VALUES(1)").Exec()
		require.Nil(t, err)
	}

	//no real rollback happens here since we are in a 'bigger' transaction
	//rollback 2
	dbc.Rollback()
	{
		err := dbc.SelectBySQL("SELECT COUNT(id) FROM foo").LoadValue(&res)
		require.Nil(t, err)
		assert.EqualValues(t, 2, res)
	}

	//rollback 1
	dbc.Rollback()

	{
		err := dbc.SelectBySQL("SELECT COUNT(id) FROM foo").LoadValue(&res)
		require.Nil(t, err)
		assert.EqualValues(t, 0, res)
	}

}