package system

import (
	"pychr/global"
	"pychr/model/system/response"
)

var AutoCodeMysql = new(autoCodeMysql)

type autoCodeMysql 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 (s *autoCodeMysql) GetDB(businessDB string) (data []response.Db, err error) {
	var entities []response.Db
	sql := "SELECT SCHEMA_NAME AS `database` FROM INFORMATION_SCHEMA.SCHEMATA;"
	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 (s *autoCodeMysql) 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_schema = ?`
	if businessDB == "" {
		err = global.GVA_DB.Raw(sql, dbName).Scan(&entities).Error
	} else {
		err = global.GVA_DBList[businessDB].Raw(sql, dbName).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 (s *autoCodeMysql) GetColumn(businessDB string, tableName string, dbName string) (data []response.Column, err error) {
	var entities []response.Column
	sql := `
	SELECT 
    c.COLUMN_NAME column_name,
    c.DATA_TYPE data_type,
    CASE c.DATA_TYPE
        WHEN 'longtext' THEN c.CHARACTER_MAXIMUM_LENGTH
        WHEN 'varchar' THEN c.CHARACTER_MAXIMUM_LENGTH
        WHEN 'double' THEN CONCAT_WS(',', c.NUMERIC_PRECISION, c.NUMERIC_SCALE)
        WHEN 'decimal' THEN CONCAT_WS(',', c.NUMERIC_PRECISION, c.NUMERIC_SCALE)
        WHEN 'int' THEN c.NUMERIC_PRECISION
        WHEN 'bigint' THEN c.NUMERIC_PRECISION
        ELSE '' 
    END AS data_type_long,
    c.COLUMN_COMMENT column_comment,
    CASE WHEN kcu.COLUMN_NAME IS NOT NULL THEN 1 ELSE 0 END AS primary_key
FROM 
    INFORMATION_SCHEMA.COLUMNS c
LEFT JOIN 
    INFORMATION_SCHEMA.KEY_COLUMN_USAGE kcu 
ON 
    c.TABLE_SCHEMA = kcu.TABLE_SCHEMA 
    AND c.TABLE_NAME = kcu.TABLE_NAME 
    AND c.COLUMN_NAME = kcu.COLUMN_NAME 
    AND kcu.CONSTRAINT_NAME = 'PRIMARY'
WHERE 
    c.TABLE_NAME = ? 
    AND c.TABLE_SCHEMA = ?;`
	if businessDB == "" {
		err = global.GVA_DB.Raw(sql, tableName, dbName).Scan(&entities).Error
	} else {
		err = global.GVA_DBList[businessDB].Raw(sql, tableName, dbName).Scan(&entities).Error
	}

	return entities, err
}
