package system

import (
	"courseSign/server/global"
	"courseSign/server/model/system/response"
	"github.com/pkg/errors"
	"gorm.io/driver/postgres"
	"gorm.io/gorm"
	"gorm.io/gorm/logger"
)

var AutoCodePgsql = new(autoCodePgsql)

type autoCodePgsql struct{}

// GetDB 获取数据库的所有数据库名
// Author [piexlmax](https://github.com/piexlmax)
// Author [SliverHorn](https://github.com/SliverHorn)
func (a *autoCodePgsql) GetDB(businessDB string) (data []response.Db, err error) {
	var entities []response.Db
	sql := `SELECT datname as database FROM pg_database WHERE datistemplate = false`
	if businessDB == "" {
		err = global.GVA_DB.Raw(sql).Scan(&entities).Error
	} else {
		err = global.GVA_DBList[businessDB].Raw(sql).Scan(&entities).Error
	}

	return entities, err
}

// GetTables 获取数据库的所有表名
// Author [piexlmax](https://github.com/piexlmax)
// Author [SliverHorn](https://github.com/SliverHorn)
func (a *autoCodePgsql) GetTables(businessDB string, dbName string) (data []response.Table, err error) {
	var entities []response.Table
	sql := `select table_name as table_name from information_schema.tables where table_catalog = ? and table_schema = ?`
	db, _err := gorm.Open(postgres.Open(global.GVA_CONFIG.Pgsql.LinkDsn(dbName)), &gorm.Config{Logger: logger.Default.LogMode(logger.Info)})
	if _err != nil {
		return nil, errors.Wrapf(err, "[pgsql] 连接 数据库(%s)的表失败!", dbName)
	}

	err = db.Raw(sql, dbName, "public").Scan(&entities).Error
	return entities, err
}

// GetColumn 获取指定数据库和指定数据表的所有字段名,类型值等
// Author [piexlmax](https://github.com/piexlmax)
// Author [SliverHorn](https://github.com/SliverHorn)
func (a *autoCodePgsql) GetColumn(businessDB string, tableName string, dbName string) (data []response.Column, err error) {
	// todo 数据获取不全, 待完善sql
	sql := `
		SELECT psc.COLUMN_NAME AS COLUMN_NAME,
 psc.udt_name AS data_type,
CASE
  psc.udt_name 
  WHEN 'text' THEN
   concat_ws ( '', '', psc.CHARACTER_MAXIMUM_LENGTH ) 
  WHEN 'varchar' THEN
   concat_ws ( '', '', psc.CHARACTER_MAXIMUM_LENGTH ) 
  WHEN 'smallint' THEN
   concat_ws ( ',', psc.NUMERIC_PRECISION, psc.NUMERIC_SCALE ) 
  WHEN 'decimal' THEN
   concat_ws ( ',', psc.NUMERIC_PRECISION, psc.NUMERIC_SCALE ) 
  WHEN 'integer' THEN
   concat_ws ( '', '', psc.NUMERIC_PRECISION ) 
  WHEN 'int4' THEN
   concat_ws ( '', '', psc.NUMERIC_PRECISION ) 
  WHEN 'int8' THEN
   concat_ws ( '', '', psc.NUMERIC_PRECISION ) 
  WHEN 'bigint' THEN
   concat_ws ( '', '', psc.NUMERIC_PRECISION ) 
  WHEN 'timestamp' THEN
   concat_ws ( '', '', psc.datetime_precision ) 
  ELSE '' 
 END AS data_type_long,
 (
   SELECT
    pd.description 
   FROM
    pg_description pd 
   WHERE
    (pd.objoid,pd.objsubid) in (
       SELECT pa.attrelid,pa.attnum
       FROM
        pg_attribute pa 
      WHERE pa.attrelid = ( SELECT oid FROM pg_class pc WHERE 
      pc.relname = psc.table_name
      ) 
      and attname = psc.column_name
    ) 
 ) AS column_comment 
FROM
 INFORMATION_SCHEMA.COLUMNS psc 
WHERE
 table_catalog = ?
 AND table_schema = 'public' 
 AND TABLE_NAME = ?;
	`
	var entities []response.Column
	db, _err := gorm.Open(postgres.Open(global.GVA_CONFIG.Pgsql.LinkDsn(dbName)), &gorm.Config{Logger: logger.Default.LogMode(logger.Info)})
	if _err != nil {
		return nil, errors.Wrapf(err, "[pgsql] 连接 数据库(%s)的表(%s)失败!", dbName, tableName)
	}
	//sql = strings.ReplaceAll(sql, "@table_catalog", dbName)
	//sql = strings.ReplaceAll(sql, "@table_name", tableName)
	err = db.Raw(sql, dbName, tableName).Scan(&entities).Error
	return entities, err
}
