package db

import (
	"database/sql"
	"errors"
	"fmt"
)

type DatabaseManager struct {
	Connections map[string]*Connection
	Factory     ConnectionFactory
	Configs     map[string]*DBConfig
}

func (dm *DatabaseManager) Connection(connectionName string) *Connection {
	connection, ok := dm.Connections[connectionName]
	if !ok {
		dm.Connections[connectionName] = dm.MakeConnection(connectionName)
		connection, _ = dm.Connections[connectionName]
	}
	return connection
}

func (dm *DatabaseManager) MakeConnection(connectionName string) *Connection {
	config, ok := dm.Configs[connectionName]

	if !ok {
		panic(errors.New(fmt.Sprintf("Database connection %s not configured.", connectionName)))
	}

	conn := dm.Factory.Make(config)
	conn.ConnectionName = connectionName
	dm.Connections[connectionName] = conn
	return conn
}

func (dm *DatabaseManager) getDefaultConnection() (defaultConnectionName string) {
	defaultConnectionName = "default"
	return
}

func (dm *DatabaseManager) Table(params ...string) *Builder {
	defaultConn := dm.getDefaultConnection()
	c := dm.Connection(defaultConn)
	builder := NewBuilder(c)
	if c.Config.Driver == DriverMysql {
		builder.Grammar = &MysqlGrammar{}
	} else if c.Config.Driver == DriverSqlite3 {
		builder.Grammar = &Sqlite3Grammar{}
	} else {
		panic("不支持的数据库类型")
	}
	builder.Grammar.SetTablePrefix(dm.Configs[defaultConn].Prefix)
	builder.Grammar.SetBuilder(builder)
	builder.Table(params...)
	return builder
}

func (dm *DatabaseManager) Select(query string, bindings []interface{}, dest interface{}) (sql.Result, error) {
	ic := dm.Connections["default"]
	return (*ic).Select(query, bindings, dest)
}

func (dm *DatabaseManager) Insert(query string, bindings []interface{}) (sql.Result, error) {
	ic := dm.Connections["default"]
	return (*ic).Insert(query, bindings)
}

func (dm *DatabaseManager) Update(query string, bindings []interface{}) (sql.Result, error) {
	ic := dm.Connections["default"]
	return (*ic).Update(query, bindings)
}

func (dm *DatabaseManager) Delete(query string, bindings []interface{}) (sql.Result, error) {
	ic := dm.Connections["default"]
	return (*ic).Delete(query, bindings)
}

func (dm *DatabaseManager) Statement(query string, bindings []interface{}) (sql.Result, error) {
	ic := dm.Connections["default"]
	return (*ic).Delete(query, bindings)
}

func (dm *DatabaseManager) Query() *Builder {
	defaultConn := dm.getDefaultConnection()
	c := dm.Connection(defaultConn)
	builder := NewBuilder(c)
	if c.Config.Driver == DriverMysql {
		builder.Grammar = &MysqlGrammar{}
	} else if c.Config.Driver == DriverSqlite3 {
		builder.Grammar = &Sqlite3Grammar{}
	} else {
		panic("不支持的数据库类型")
	}
	builder.Grammar.SetTablePrefix(dm.Configs[defaultConn].Prefix)
	builder.Grammar.SetBuilder(builder)
	return builder
}

func (dm *DatabaseManager) Transaction(closure TxClosure) (interface{}, error) {
	ic := dm.Connections["default"]
	return (*ic).Transaction(closure)
}

func (dm *DatabaseManager) BeginTransaction() (*Transaction, error) {
	ic := dm.Connections["default"]
	return (*ic).BeginTransaction()
}