package sqlstore

import (
	"context"
	"fmt"
	"net/url"
	"os"
	"path"
	"path/filepath"
	"strings"
	"sync"
	"time"

	"github.com/go-sql-driver/mysql"
	"github.com/grafana/grafana/pkg/bus"
	"github.com/grafana/grafana/pkg/infra/fs"
	"github.com/grafana/grafana/pkg/infra/localcache"
	"github.com/grafana/grafana/pkg/infra/log"
	"github.com/grafana/grafana/pkg/models"
	"github.com/grafana/grafana/pkg/registry"
	"github.com/grafana/grafana/pkg/services/annotations"
	"github.com/grafana/grafana/pkg/services/sqlstore/migrations"
	"github.com/grafana/grafana/pkg/services/sqlstore/migrator"
	"github.com/grafana/grafana/pkg/services/sqlstore/sqlutil"
	"github.com/grafana/grafana/pkg/setting"
	"github.com/grafana/grafana/pkg/util"
	"github.com/grafana/grafana/pkg/util/errutil"
	_ "github.com/lib/pq"
	"xorm.io/xorm"
)

var (
	x       *xorm.Engine
	dialect migrator.Dialect

	sqlog log.Logger = log.New("sqlstore")
)

// ContextSessionKey is used as key to save values in `context.Context`
type ContextSessionKey struct{}

type SQLStore struct {
	Cfg          *setting.Cfg
	Bus          bus.Bus
	CacheService *localcache.CacheService

	dbCfg                       DatabaseConfig
	engine                      *xorm.Engine
	log                         log.Logger
	Dialect                     migrator.Dialect
	skipEnsureDefaultOrgAndUser bool
	migrations                  registry.DatabaseMigrator
}

func ProvideService(cfg *setting.Cfg, cacheService *localcache.CacheService, bus bus.Bus, migrations registry.DatabaseMigrator) (*SQLStore, error) {
	// This change will make xorm use an empty default schema for postgres and
	// by that mimic the functionality of how it was functioning before
	// xorm's changes above.
	xorm.DefaultPostgresSchema = ""
	s, err := newSQLStore(cfg, cacheService, bus, nil, migrations)
	if err != nil {
		return nil, err
	}

	if err := s.Migrate(); err != nil {
		return nil, err
	}

	if err := s.Reset(); err != nil {
		return nil, err
	}

	return s, nil
}

func ProvideServiceForTests(migrations registry.DatabaseMigrator) (*SQLStore, error) {
	return initTestDB(migrations, InitTestDBOpt{EnsureDefaultOrgAndUser: true})
}

func newSQLStore(cfg *setting.Cfg, cacheService *localcache.CacheService, bus bus.Bus, engine *xorm.Engine,
	migrations registry.DatabaseMigrator, opts ...InitTestDBOpt) (*SQLStore, error) {
	ss := &SQLStore{
		Cfg:                         cfg,
		Bus:                         bus,
		CacheService:                cacheService,
		log:                         log.New("sqlstore"),
		skipEnsureDefaultOrgAndUser: false,
		migrations:                  migrations,
	}
	for _, opt := range opts {
		if !opt.EnsureDefaultOrgAndUser {
			ss.skipEnsureDefaultOrgAndUser = true
		}
	}

	if err := ss.initEngine(engine); err != nil {
		return nil, errutil.Wrap("failed to connect to database", err)
	}

	ss.Dialect = migrator.NewDialect(ss.engine)

	// temporarily still set global var
	x = ss.engine
	dialect = ss.Dialect

	// Init repo instances
	annotations.SetRepository(&SQLAnnotationRepo{})
	annotations.SetAnnotationCleaner(&AnnotationCleanupService{batchSize: ss.Cfg.AnnotationCleanupJobBatchSize, log: log.New("annotationcleaner")})
	ss.Bus.SetTransactionManager(ss)

	// Register handlers
	ss.addUserQueryAndCommandHandlers()
	ss.addAlertNotificationUidByIdHandler()
	ss.addPreferencesQueryAndCommandHandlers()
	ss.addDashboardQueryAndCommandHandlers()
	ss.addDashboardACLQueryAndCommandHandlers()
	ss.addQuotaQueryAndCommandHandlers()
	ss.addOrgUsersQueryAndCommandHandlers()

	// if err := ss.Reset(); err != nil {
	// 	return nil, err
	// }
	// // Make sure the changes are synced, so they get shared with eventual other DB connections
	// // XXX: Why is this only relevant when not skipping migrations?
	// if !ss.dbCfg.SkipMigrations {
	// 	if err := ss.Sync(); err != nil {
	// 		return nil, err
	// 	}
	// }

	return ss, nil
}

// Migrate performs database migrations.
// Has to be done in a second phase (after initialization), since other services can register migrations during
// the initialization phase.
func (ss *SQLStore) Migrate() error {
	if ss.dbCfg.SkipMigrations {
		return nil
	}

	migrator := migrator.NewMigrator(ss.engine, ss.Cfg)
	ss.migrations.AddMigration(migrator)

	return migrator.Start()
}

// Sync syncs changes to the database.
func (ss *SQLStore) Sync() error {
	return ss.engine.Sync2()
}

// Reset resets database state.
// If default org and user creation is enabled, it will be ensured they exist in the database.
func (ss *SQLStore) Reset() error {
	if ss.skipEnsureDefaultOrgAndUser {
		return nil
	}

	return ss.ensureMainOrgAndAdminUser()
}

func (ss *SQLStore) ensureMainOrgAndAdminUser() error {
	ctx := context.Background()
	err := ss.WithTransactionalDbSession(ctx, func(sess *DBSession) error {
		ss.log.Debug("Ensuring main org and admin user exist")
		var stats models.SystemUserCountStats
		// TODO: Should be able to rename "Count" to "count", for more standard SQL style
		// Just have to make sure it gets deserialized properly into models.SystemUserCountStats
		rawSQL := `SELECT COUNT(id) AS Count FROM ` + dialect.Quote("user")
		if _, err := sess.SQL(rawSQL).Get(&stats); err != nil {
			return fmt.Errorf("could not determine if admin user exists: %w", err)
		}

		if stats.Count > 0 {
			return nil
		}

		// ensure admin user
		if !ss.Cfg.DisableInitAdminCreation {
			ss.log.Debug("Creating default admin user")
			if _, err := ss.createUser(ctx, sess, userCreationArgs{
				Login:    ss.Cfg.AdminUser,
				Email:    ss.Cfg.AdminUser + "@localhost",
				Password: ss.Cfg.AdminPassword,
				IsAdmin:  true,
			}, false); err != nil {
				return fmt.Errorf("failed to create admin user: %s", err)
			}

			ss.log.Info("Created default admin", "user", ss.Cfg.AdminUser)
			// Why should we return and not create the default org in this case?
			// Returning here breaks tests using anonymous access
			// return nil
		}

		ss.log.Debug("Creating default org", "name", MainOrgName)
		if _, err := ss.getOrCreateOrg(sess, MainOrgName); err != nil {
			return fmt.Errorf("failed to create default organization: %w", err)
		}

		ss.log.Info("Created default organization")
		return nil
	})

	return err
}

func (ss *SQLStore) buildExtraConnectionString(sep rune) string {
	if ss.dbCfg.UrlQueryParams == nil {
		return ""
	}

	var sb strings.Builder
	for key, values := range ss.dbCfg.UrlQueryParams {
		for _, value := range values {
			sb.WriteRune(sep)
			sb.WriteString(key)
			sb.WriteRune('=')
			sb.WriteString(value)
		}
	}
	return sb.String()
}

func (ss *SQLStore) buildConnectionString() (string, error) {
	if err := ss.readConfig(); err != nil {
		return "", err
	}

	cnnstr := ss.dbCfg.ConnectionString

	// special case used by integration tests
	if cnnstr != "" {
		return cnnstr, nil
	}

	switch ss.dbCfg.Type {
	case migrator.MySQL:
		protocol := "tcp"
		if strings.HasPrefix(ss.dbCfg.Host, "/") {
			protocol = "unix"
		}

		cnnstr = fmt.Sprintf("%s:%s@%s(%s)/%s?collation=utf8mb4_unicode_ci&allowNativePasswords=true",
			ss.dbCfg.User, ss.dbCfg.Pwd, protocol, ss.dbCfg.Host, ss.dbCfg.Name)

		if ss.dbCfg.SslMode == "true" || ss.dbCfg.SslMode == "skip-verify" {
			tlsCert, err := makeCert(ss.dbCfg)
			if err != nil {
				return "", err
			}
			if err := mysql.RegisterTLSConfig("custom", tlsCert); err != nil {
				return "", err
			}

			cnnstr += "&tls=custom"
		}

		if isolation := ss.dbCfg.IsolationLevel; isolation != "" {
			val := url.QueryEscape(fmt.Sprintf("'%s'", isolation))
			cnnstr += fmt.Sprintf("&tx_isolation=%s", val)
		}

		cnnstr += ss.buildExtraConnectionString('&')
	case migrator.Postgres:
		addr, err := util.SplitHostPortDefault(ss.dbCfg.Host, "127.0.0.1", "5432")
		if err != nil {
			return "", errutil.Wrapf(err, "Invalid host specifier '%s'", ss.dbCfg.Host)
		}

		if ss.dbCfg.Pwd == "" {
			ss.dbCfg.Pwd = "''"
		}
		if ss.dbCfg.User == "" {
			ss.dbCfg.User = "''"
		}
		cnnstr = fmt.Sprintf("user=%s password=%s host=%s port=%s dbname=%s sslmode=%s sslcert=%s sslkey=%s sslrootcert=%s",
			ss.dbCfg.User, ss.dbCfg.Pwd, addr.Host, addr.Port, ss.dbCfg.Name, ss.dbCfg.SslMode, ss.dbCfg.ClientCertPath,
			ss.dbCfg.ClientKeyPath, ss.dbCfg.CaCertPath)

		cnnstr += ss.buildExtraConnectionString(' ')
	case migrator.SQLite:
		// special case for tests
		if !filepath.IsAbs(ss.dbCfg.Path) {
			ss.dbCfg.Path = filepath.Join(ss.Cfg.DataPath, ss.dbCfg.Path)
		}
		if err := os.MkdirAll(path.Dir(ss.dbCfg.Path), os.ModePerm); err != nil {
			return "", err
		}

		cnnstr = fmt.Sprintf("file:%s?cache=%s&mode=rwc", ss.dbCfg.Path, ss.dbCfg.CacheMode)
		cnnstr += ss.buildExtraConnectionString('&')
	default:
		return "", fmt.Errorf("unknown database type: %s", ss.dbCfg.Type)
	}

	return cnnstr, nil
}

// initEngine initializes ss.engine.
func (ss *SQLStore) initEngine(engine *xorm.Engine) error {
	if ss.engine != nil {
		sqlog.Debug("Already connected to database")
		return nil
	}

	connectionString, err := ss.buildConnectionString()
	if err != nil {
		return err
	}

	if ss.Cfg.IsDatabaseMetricsEnabled() {
		ss.dbCfg.Type = WrapDatabaseDriverWithHooks(ss.dbCfg.Type)
	}

	sqlog.Info("Connecting to DB", "dbtype", ss.dbCfg.Type)
	if ss.dbCfg.Type == migrator.SQLite && strings.HasPrefix(connectionString, "file:") &&
		!strings.HasPrefix(connectionString, "file::memory:") {
		exists, err := fs.Exists(ss.dbCfg.Path)
		if err != nil {
			return errutil.Wrapf(err, "can't check for existence of %q", ss.dbCfg.Path)
		}

		const perms = 0640
		if !exists {
			ss.log.Info("Creating SQLite database file", "path", ss.dbCfg.Path)
			f, err := os.OpenFile(ss.dbCfg.Path, os.O_CREATE|os.O_RDWR, perms)
			if err != nil {
				return errutil.Wrapf(err, "failed to create SQLite database file %q", ss.dbCfg.Path)
			}
			if err := f.Close(); err != nil {
				return errutil.Wrapf(err, "failed to create SQLite database file %q", ss.dbCfg.Path)
			}
		} else {
			fi, err := os.Lstat(ss.dbCfg.Path)
			if err != nil {
				return errutil.Wrapf(err, "failed to stat SQLite database file %q", ss.dbCfg.Path)
			}
			m := fi.Mode() & os.ModePerm
			if m|perms != perms {
				ss.log.Warn("SQLite database file has broader permissions than it should",
					"path", ss.dbCfg.Path, "mode", m, "expected", os.FileMode(perms))
			}
		}
	}
	if engine == nil {
		var err error
		engine, err = xorm.NewEngine(ss.dbCfg.Type, connectionString)
		if err != nil {
			return err
		}
	}

	engine.SetMaxOpenConns(ss.dbCfg.MaxOpenConn)
	engine.SetMaxIdleConns(ss.dbCfg.MaxIdleConn)
	engine.SetConnMaxLifetime(time.Second * time.Duration(ss.dbCfg.ConnMaxLifetime))

	// configure sql logging
	debugSQL := ss.Cfg.Raw.Section("database").Key("log_queries").MustBool(false)
	if !debugSQL {
		engine.SetLogger(&xorm.DiscardLogger{})
	} else {
		engine.SetLogger(NewXormLogger(log.LvlInfo, log.New("sqlstore.xorm")))
		engine.ShowSQL(true)
		engine.ShowExecTime(true)
	}

	ss.engine = engine
	return nil
}

// readConfig initializes the SQLStore from its configuration.
func (ss *SQLStore) readConfig() error {
	sec := ss.Cfg.Raw.Section("database")

	cfgURL := sec.Key("url").String()
	if len(cfgURL) != 0 {
		dbURL, err := url.Parse(cfgURL)
		if err != nil {
			return err
		}
		ss.dbCfg.Type = dbURL.Scheme
		ss.dbCfg.Host = dbURL.Host

		pathSplit := strings.Split(dbURL.Path, "/")
		if len(pathSplit) > 1 {
			ss.dbCfg.Name = pathSplit[1]
		}

		userInfo := dbURL.User
		if userInfo != nil {
			ss.dbCfg.User = userInfo.Username()
			ss.dbCfg.Pwd, _ = userInfo.Password()
		}

		ss.dbCfg.UrlQueryParams = dbURL.Query()
	} else {
		ss.dbCfg.Type = sec.Key("type").String()
		ss.dbCfg.Host = sec.Key("host").String()
		ss.dbCfg.Name = sec.Key("name").String()
		ss.dbCfg.User = sec.Key("user").String()
		ss.dbCfg.ConnectionString = sec.Key("connection_string").String()
		ss.dbCfg.Pwd = sec.Key("password").String()
	}

	ss.dbCfg.MaxOpenConn = sec.Key("max_open_conn").MustInt(0)
	ss.dbCfg.MaxIdleConn = sec.Key("max_idle_conn").MustInt(2)
	ss.dbCfg.ConnMaxLifetime = sec.Key("conn_max_lifetime").MustInt(14400)

	ss.dbCfg.SslMode = sec.Key("ssl_mode").String()
	ss.dbCfg.CaCertPath = sec.Key("ca_cert_path").String()
	ss.dbCfg.ClientKeyPath = sec.Key("client_key_path").String()
	ss.dbCfg.ClientCertPath = sec.Key("client_cert_path").String()
	ss.dbCfg.ServerCertName = sec.Key("server_cert_name").String()
	ss.dbCfg.Path = sec.Key("path").MustString("data/grafana.db")
	ss.dbCfg.IsolationLevel = sec.Key("isolation_level").String()

	ss.dbCfg.CacheMode = sec.Key("cache_mode").MustString("private")
	ss.dbCfg.SkipMigrations = sec.Key("skip_migrations").MustBool()
	return nil
}

// ITestDB is an interface of arguments for testing db
type ITestDB interface {
	Helper()
	Fatalf(format string, args ...interface{})
	Logf(format string, args ...interface{})
	Log(args ...interface{})
}

var testSQLStore *SQLStore
var testSQLStoreMutex sync.Mutex

// InitTestDBOpt contains options for InitTestDB.
type InitTestDBOpt struct {
	// EnsureDefaultOrgAndUser flags whether to ensure that default org and user exist.
	EnsureDefaultOrgAndUser bool
}

// InitTestDBWithMigration initializes the test DB given custom migrations.
func InitTestDBWithMigration(t ITestDB, migration registry.DatabaseMigrator, opts ...InitTestDBOpt) *SQLStore {
	t.Helper()
	store, err := initTestDB(migration, opts...)
	if err != nil {
		t.Fatalf("failed to initialize sql store: %s", err)
	}
	return store
}

// InitTestDB initializes the test DB.
func InitTestDB(t ITestDB, opts ...InitTestDBOpt) *SQLStore {
	t.Helper()
	store, err := initTestDB(&migrations.OSSMigrations{}, opts...)
	if err != nil {
		t.Fatalf("failed to initialize sql store: %s", err)
	}
	return store
}

func initTestDB(migration registry.DatabaseMigrator, opts ...InitTestDBOpt) (*SQLStore, error) {
	testSQLStoreMutex.Lock()
	defer testSQLStoreMutex.Unlock()
	if testSQLStore == nil {
		dbType := migrator.SQLite

		if len(opts) == 0 {
			opts = []InitTestDBOpt{{EnsureDefaultOrgAndUser: false}}
		}

		// environment variable present for test db?
		if db, present := os.LookupEnv("GRAFANA_TEST_DB"); present {
			dbType = db
		}

		// set test db config
		cfg := setting.NewCfg()
		sec, err := cfg.Raw.NewSection("database")
		if err != nil {
			return nil, err
		}
		if _, err := sec.NewKey("type", dbType); err != nil {
			return nil, err
		}

		switch dbType {
		case "mysql":
			if _, err := sec.NewKey("connection_string", sqlutil.MySQLTestDB().ConnStr); err != nil {
				return nil, err
			}
		case "postgres":
			if _, err := sec.NewKey("connection_string", sqlutil.PostgresTestDB().ConnStr); err != nil {
				return nil, err
			}
		default:
			if _, err := sec.NewKey("connection_string", sqlutil.SQLite3TestDB().ConnStr); err != nil {
				return nil, err
			}
		}

		// useful if you already have a database that you want to use for tests.
		// cannot just set it on testSQLStore as it overrides the config in Init
		if _, present := os.LookupEnv("SKIP_MIGRATIONS"); present {
			if _, err := sec.NewKey("skip_migrations", "true"); err != nil {
				return nil, err
			}
		}

		// need to get engine to clean db before we init
		engine, err := xorm.NewEngine(dbType, sec.Key("connection_string").String())
		if err != nil {
			return nil, err
		}

		engine.DatabaseTZ = time.UTC
		engine.TZLocation = time.UTC

		testSQLStore, err = newSQLStore(cfg, localcache.New(5*time.Minute, 10*time.Minute), bus.GetBus(), engine, migration, opts...)
		if err != nil {
			return nil, err
		}

		if err := testSQLStore.Migrate(); err != nil {
			return nil, err
		}

		if err := dialect.TruncateDBTables(); err != nil {
			return nil, err
		}

		if err := testSQLStore.Reset(); err != nil {
			return nil, err
		}

		// Make sure the changes are synced, so they get shared with eventual other DB connections
		// XXX: Why is this only relevant when not skipping migrations?
		if !testSQLStore.dbCfg.SkipMigrations {
			if err := testSQLStore.Sync(); err != nil {
				return nil, err
			}
		}

		// temp global var until we get rid of global vars
		dialect = testSQLStore.Dialect
		return testSQLStore, nil
	}

	if err := dialect.TruncateDBTables(); err != nil {
		return nil, err
	}
	if err := testSQLStore.Reset(); err != nil {
		return nil, err
	}

	return testSQLStore, nil
}

func IsTestDbMySQL() bool {
	if db, present := os.LookupEnv("GRAFANA_TEST_DB"); present {
		return db == migrator.MySQL
	}

	return false
}

func IsTestDbPostgres() bool {
	if db, present := os.LookupEnv("GRAFANA_TEST_DB"); present {
		return db == migrator.Postgres
	}

	return false
}

func IsTestDBMSSQL() bool {
	if db, present := os.LookupEnv("GRAFANA_TEST_DB"); present {
		return db == migrator.MSSQL
	}

	return false
}

type DatabaseConfig struct {
	Type             string
	Host             string
	Name             string
	User             string
	Pwd              string
	Path             string
	SslMode          string
	CaCertPath       string
	ClientKeyPath    string
	ClientCertPath   string
	ServerCertName   string
	ConnectionString string
	IsolationLevel   string
	MaxOpenConn      int
	MaxIdleConn      int
	ConnMaxLifetime  int
	CacheMode        string
	UrlQueryParams   map[string][]string
	SkipMigrations   bool
}