package accesscontrol

import (
	"xorm.io/xorm"

	"github.com/grafana/grafana/pkg/services/sqlstore/migrator"
)

const migSQLITERoleNameNullable = `ALTER TABLE seed_assignment ADD COLUMN tmp_role_name VARCHAR(190) DEFAULT NULL;
UPDATE seed_assignment SET tmp_role_name = role_name;
ALTER TABLE seed_assignment DROP COLUMN role_name;
ALTER TABLE seed_assignment RENAME COLUMN tmp_role_name TO role_name;`

func AddSeedAssignmentMigrations(mg *migrator.Migrator) {
	seedAssignmentTable := migrator.Table{Name: "seed_assignment"}

	mg.AddMigration("add action column to seed_assignment",
		migrator.NewAddColumnMigration(seedAssignmentTable,
			&migrator.Column{Name: "action", Type: migrator.DB_Varchar, Length: 190, Nullable: true}))

	mg.AddMigration("add scope column to seed_assignment",
		migrator.NewAddColumnMigration(seedAssignmentTable,
			&migrator.Column{Name: "scope", Type: migrator.DB_Varchar, Length: 190, Nullable: true}))

	mg.AddMigration("remove unique index builtin_role_role_name before nullable update",
		migrator.NewDropIndexMigration(seedAssignmentTable,
			&migrator.Index{Cols: []string{"builtin_role", "role_name"}, Type: migrator.UniqueIndex}))

	mg.AddMigration("update seed_assignment role_name column to nullable",
		migrator.NewRawSQLMigration("").
			SQLite(migSQLITERoleNameNullable).
			Postgres("ALTER TABLE `seed_assignment` ALTER COLUMN role_name DROP NOT NULL;").
			Mysql("ALTER TABLE seed_assignment MODIFY role_name VARCHAR(190) DEFAULT NULL;"))

	mg.AddMigration("add unique index builtin_role_name back",
		migrator.NewAddIndexMigration(seedAssignmentTable,
			&migrator.Index{Cols: []string{"builtin_role", "role_name"}, Type: migrator.UniqueIndex}))

	mg.AddMigration("add unique index builtin_role_action_scope",
		migrator.NewAddIndexMigration(seedAssignmentTable,
			&migrator.Index{Cols: []string{"builtin_role", "action", "scope"}, Type: migrator.UniqueIndex}))

	mg.AddMigration("add primary key to seed_assigment", &seedAssignmentPrimaryKeyMigrator{})
}

type seedAssignmentPrimaryKeyMigrator struct {
	migrator.MigrationBase
}

func (m *seedAssignmentPrimaryKeyMigrator) SQL(dialect migrator.Dialect) string {
	return CodeMigrationSQL
}

func (m *seedAssignmentPrimaryKeyMigrator) Exec(sess *xorm.Session, mig *migrator.Migrator) error {
	driver := mig.Dialect.DriverName()

	if driver == migrator.MySQL {
		_, err := sess.Exec("ALTER TABLE seed_assignment ADD id INT NOT NULL AUTO_INCREMENT FIRST, ADD PRIMARY KEY (id)")
		return err
	} else if driver == migrator.Postgres {
		_, err := sess.Exec("ALTER TABLE seed_assignment ADD COLUMN id SERIAL PRIMARY KEY")
		return err
	}

	// sqlite does not allow to add constraint after a table is created
	// We need to create a new table with desired columns, move data to new table, delete old table and rename new table to old

	// create temp table
	_, err := sess.Exec(`
		CREATE TABLE seed_assignment_temp (
		    id INTEGER PRIMARY KEY AUTOINCREMENT,
			builtin_role TEXT,
			action TEXT,
			scope TEXT,
			role_name TEXT
		);
	`)
	if err != nil {
		return err
	}

	// copy data to temp table
	_, err = sess.Exec("INSERT INTO seed_assignment_temp (builtin_role, action, scope, role_name) SELECT * FROM seed_assignment;")
	if err != nil {
		return err
	}

	// drop indices on old table
	_, err = sess.Exec("DROP INDEX UQE_seed_assignment_builtin_role_action_scope;")
	if err != nil {
		return err
	}
	_, err = sess.Exec("DROP INDEX UQE_seed_assignment_builtin_role_role_name;")
	if err != nil {
		return err
	}

	// drop old table
	_, err = sess.Exec("DROP TABLE seed_assignment;")
	if err != nil {
		return err
	}

	// rename temp table to old name
	_, err = sess.Exec("ALTER TABLE seed_assignment_temp RENAME TO seed_assignment;")
	if err != nil {
		return err
	}

	// recreate indexes on new table
	_, err = sess.Exec("CREATE UNIQUE INDEX UQE_seed_assignment_builtin_role_action_scope ON seed_assignment (builtin_role, action, scope);")
	if err != nil {
		return err
	}
	_, err = sess.Exec("CREATE UNIQUE INDEX UQE_seed_assignment_builtin_role_role_name ON seed_assignment (builtin_role, role_name);")
	if err != nil {
		return err
	}

	return nil
}