package model

import (
	"strconv"
	"strings"
	"time"

	"gorm.io/driver/postgres"
	"gorm.io/gorm"
	"qoobing.com/gomod/log"
	"qoobing.com/gomod/redis"
	"qoobing.com/gomod/database"
)


type Model struct {
    DB         *gorm.DB
    DbTxStatus DbTxStatus
    Redis      redis.Conn
    RedisPool  *redis.Pool
}

type DbTxStatus int
const (
    DBTX_STATUS_TX_NONE    DbTxStatus = 0
    DBTX_STATUS_TX_DOING   DbTxStatus = 1
    DBTX_STATUS_TX_SUCCESS DbTxStatus = 2
    DBTX_STATUS_TX_FAILED  DbTxStatus = 3
)

var (
	defaultDb         *database.Config 
	defaultDsn        string
	defaultDbDebug    bool
	defaultGormDB     *gorm.DB
	defaultRds        redis.Config
	defaultRedis      *redis.Pool
	defaultRedisDebug bool
	defaultOptions  []Option
)

func NewModel() *Model {
    if len(defaultOptions) == 0 {
        panic("No defualt Database&Redis been configed")
    } 
    return NewModelWithOption(defaultOptions...)
}

func NewModelDefault() *Model {
	return mdb.NewModelWithOption(OptOpenDefaultDatabase, OptOpenDefaultRedis)
}

func NewModelDefaultRedis() *Model {
	return mdb.NewModelWithOption(OptOpenDefaultRedis)
}

func NewModelDefaultDatabase() *Model {
	return mdb.NewModelWithOption(OptOpenDefaultDatabase)
}

func NewModelWithOption(options ...Option) *Model {
    n := 0
    m := Model{}
    log.Debugf("Start NewModelWithOption...")
    for _, option := range options {
        n++
        option(&m)
    }
    log.Debugf("Finish NewModelWithOption(with %d options)", n)
    return &m
}

func (m *Model) Close() {
    if m.Redis != nil {
        m.Redis.Close()
    }   
    if m.DB == nil {
        m.DbTxStatus = DBTX_STATUS_TX_NONE
    } else if m.DbTxStatus == DBTX_STATUS_TX_DOING {
        m.DB.Rollback()
        m.DbTxStatus = DBTX_STATUS_TX_FAILED
    }   
}

func (m *Model) Begin() {
    if m.DB == nil {
        panic("unreachable code, m.DB is uninitialized")
    } else if m.DbTxStatus != DBTX_STATUS_TX_NONE {
        panic("unreachable code, begin transaction towice???")
    } else {
        m.DbTxStatus = DBTX_STATUS_TX_DOING
        m.DB = m.DB.Begin()
    }
}

func (m *Model) Commit() error {
    if m.DB == nil {
        panic("unreachable code, m.DB is uninitialized")
    } else if m.DbTxStatus != DBTX_STATUS_TX_DOING {
        return nil 
    } else if err := m.DB.Commit().Error; err != nil {
        m.DbTxStatus = DBTX_STATUS_TX_FAILED
        return err 
    } else {
        m.DbTxStatus = DBTX_STATUS_TX_SUCCESS
        return nil 
    }   
}

// Option is model's option
type Option func(*Model)

// OptOpenDefaultDatabase option function for open default database
func OptOpenDefaultDatabase(m *Model) {
	if defaultGormDB != nil {
		m.DB = defaultGormDB
	} else if db, err := gorm.Open(
		postgres.New(postgres.Config{
			DSN:                  defaultDsn,
			PreferSimpleProtocol: true,
		}), &gorm.Config{}); err != nil {
		panic("DATABASE_OPEN_ERROR")
	} else {
		if defaultDbDebug {
			m.DB = db.Debug()
		} else {
			m.DB = db
		}
		if sqlDB, err := m.DB.DB(); err != nil {
			panic("DATABASE_OPEN_ERROR")
		} else {
			sqlDB.SetMaxIdleConns(3)
			sqlDB.SetMaxOpenConns(10)
			sqlDB.SetConnMaxLifetime(time.Minute)
		}
		defaultGormDB = m.DB
	}
	//TODO: check cocurrent
	m.DB = m.DB.Session(&gorm.Session{QueryFields: true})
	log.Debugf("Opt for open default database done")
	return
}

// OptOpenDefaultRedisSentinelPool option function for open default redis sentinel
func OptOpenDefaultRedis(m *Model) {
	if defaultRedis != nil {
		m.Redis = defaultRedis.Get()
		m.RedisPool = defaultRedis
	} else if pool := sentinel.NewPool(defaultRds); pool == nil {
		panic("REDIS_ERROR")
	} else {
		defaultRedis = pool
		m.Redis = defaultRedis.Get()
		m.RedisPool = defaultRedis
	}

	log.Debugf("Opt for open default redis done")
	return
}

// Init init default database config & redis config 
func Init(defaultDb *database.Config, defaultRds *redis.Config){ 
    defaultOptions = []Options{}

    if defaultDb {
    	// database init
    	arrConfStr := []string{
    		"host=" + defaultDb.Host,
    		"port=" + strconv.Itoa(defaultDb.Port),
    		"user=" + defaultDb.Username,
    		"password=" + defaultDb.Password,
    		"dbname=" + defaultDb.Dbname,
    		defaultDb.ExtraParameters,
    	}
    	defaultDsn = strings.Join(arrConfStr, " ")
    	defaultDbDebug = defaultDb.Debug
    	// database debug
    	if defaultDbDebug && len(defaultDb.Password) > 5 {
    		p := defaultDb.Password
    		l := len(p)
    		secDefaultDsn := strings.Replace(defaultDsn, p[2:l-3], "*****", 1)
    		log.Debugf("defaultDsn='%s'", secDefaultDsn)
    	}

        defaultOptions = append(defaultOptions, OptOpenDefaultDatabase)
    }

    if defaultRds != nil {
	    // redis init
	    defaultRds = coreRedis
	    defaultRedisDebug = coreRedis.Debug
        // redis debug
	    if defaultRedisDebug && len(coreRedis.Password) > 5 {
	    	p := coreRedis.Password
	    	l := len(p)
	    	secDefaultRds := defaultRds
	    	secDefaultRds.Password = strings.Replace(p, p[2:l-3], "*****", 1)
	    	log.PrintPretty("defaultRds=", secDefaultRds)
	    }
        defaultOptions = append(defaultOptions, OptOpenDefaultRedis)
    }
}