package pgsql

import (
	"errors"
	"fmt"

	"gorm.io/gorm"
	"zestack.dev/env"
)

func PublicSchema() string {
	return env.String("DB_PUBLIC_SCHEMA", "public")
}

func TenantBasename() string {
	return env.String("TENANT_BASENAME", "tenant_")
}

func TenantSchema(tenant uint) string {
	if tenant == 0 {
		return PublicSchema()
	}
	return fmt.Sprintf("%s%d", TenantBasename(), tenant)
}

func SetSearchPath(tx *gorm.DB, schema string) (reset func() error, err error) {
	// tx = tx.Session(&gorm.Session{})
	if schema == "" {
		err = errors.New("schema name is empty")
		tx.AddError(err)
		return
	}

	if schema == CurrentSearchPath(tx) {
		reset = func() error { return nil }
		return
	}

	sqlstr := "SET search_path TO " + tx.Statement.Quote(schema)
	if execErr := tx.Exec(sqlstr).Error; execErr != nil {
		err = fmt.Errorf("failed to set search path %q: %w", schema, execErr)
		tx.AddError(err)
		return
	}

	reset = func() error {
		publicSchema := PublicSchema()
		if schema == publicSchema {
			return nil
		}
		return tx.Exec("SET search_path TO " + tx.Statement.Quote(publicSchema)).Error
	}

	return
}

func CurrentSearchPath(tx *gorm.DB) string {
	// tx = tx.Session(&gorm.Session{})
	var searchPath string
	tx.Raw("SHOW search_path").Scan(&searchPath)
	if searchPath == `"$user", public` {
		return "public"
	}
	return searchPath
}