package dm

import (
	"database/sql"
	"fmt"
	"mayfly-go/internal/db/dbm/dbi"
	"mayfly-go/pkg/logx"
	"mayfly-go/pkg/utils/collx"
	"mayfly-go/pkg/utils/stringx"
	"strings"
	"time"

	"github.com/kanzihuang/vitess/go/vt/sqlparser"

	_ "gitee.com/chunanyong/dm"
)

type DMDialect struct {
	dbi.DefaultDialect

	dc *dbi.DbConn
}

func (dd *DMDialect) BatchInsert(tx *sql.Tx, tableName string, columns []string, values [][]any, duplicateStrategy int) (int64, error) {
	// 执行批量insert sql
	// insert into "table_name" ("column1", "column2", ...) values (value1, value2, ...)

	// 无需处理重复数据，直接执行批量insert
	if duplicateStrategy == dbi.DuplicateStrategyNone || duplicateStrategy == 0 {
		return dd.batchInsertSimple(tx, tableName, columns, values)
	} else { // 执行MERGE INTO语句
		return dd.batchInsertMerge(tx, tableName, columns, values)
	}
}

func (dd *DMDialect) batchInsertSimple(tx *sql.Tx, tableName string, columns []string, values [][]any) (int64, error) {
	// 生成占位符字符串：如：(?,?)
	// 重复字符串并用逗号连接
	repeated := strings.Repeat("?,", len(columns))
	// 去除最后一个逗号，占位符由括号包裹
	placeholder := fmt.Sprintf("(%s)", strings.TrimSuffix(repeated, ","))

	identityInsert := fmt.Sprintf("set identity_insert \"%s\" on;", tableName)

	sqlTemp := fmt.Sprintf("%s insert into %s (%s) values %s", identityInsert, dd.dc.GetMetaData().QuoteIdentifier(tableName), strings.Join(columns, ","), placeholder)
	effRows := 0
	// 设置允许填充自增列之后，显示指定列名可以插入自增列
	for _, value := range values {
		// 达梦数据库只能一条条的执行insert
		res, err := dd.dc.TxExec(tx, sqlTemp, value...)
		if err != nil {
			logx.Errorf("执行sql失败：%s, sql: [ %s ]", err.Error(), sqlTemp)
			return 0, err
		}
		effRows += int(res)
	}
	// 执行批量insert sql
	return int64(effRows), nil
}

func (dd *DMDialect) batchInsertMerge(tx *sql.Tx, tableName string, columns []string, values [][]any) (int64, error) {
	// 查询主键字段
	uniqueCols := make([]string, 0)
	caseSqls := make([]string, 0)
	metadata := dd.dc.GetMetaData()
	tableCols, _ := metadata.GetColumns(tableName)
	identityCols := make([]string, 0)
	for _, col := range tableCols {
		if col.IsPrimaryKey {
			uniqueCols = append(uniqueCols, col.ColumnName)
			caseSqls = append(caseSqls, fmt.Sprintf("( T1.%s = T2.%s )", metadata.QuoteIdentifier(col.ColumnName), metadata.QuoteIdentifier(col.ColumnName)))
		}
		if col.IsIdentity {
			// 自增字段不放入insert内，即使是设置了identity_insert on也不起作用
			identityCols = append(identityCols, metadata.QuoteIdentifier(col.ColumnName))
		}
	}
	// 查询唯一索引涉及到的字段，并组装到match条件内
	indexs, _ := metadata.GetTableIndex(tableName)
	if indexs != nil {
		for _, index := range indexs {
			if index.IsUnique {
				cols := strings.Split(index.ColumnName, ",")
				tmp := make([]string, 0)
				for _, col := range cols {
					uniqueCols = append(uniqueCols, col)
					tmp = append(tmp, fmt.Sprintf(" T1.%s = T2.%s ", metadata.QuoteIdentifier(col), metadata.QuoteIdentifier(col)))
				}
				caseSqls = append(caseSqls, fmt.Sprintf("( %s )", strings.Join(tmp, " AND ")))
			}
		}
	}

	// 重复数据处理策略
	phs := make([]string, 0)
	insertVals := make([]string, 0)
	upds := make([]string, 0)
	insertCols := make([]string, 0)
	for _, column := range columns {
		phs = append(phs, fmt.Sprintf("? %s", column))
		if !collx.ArrayContains(uniqueCols, metadata.RemoveQuote(column)) {
			upds = append(upds, fmt.Sprintf("T1.%s = T2.%s", column, column))
		}
		if !collx.ArrayContains(identityCols, column) {
			insertCols = append(insertCols, fmt.Sprintf("%s", column))
			insertVals = append(insertVals, fmt.Sprintf("T2.%s", column))
		}

	}
	t2s := make([]string, 0)
	for i := 0; i < len(values); i++ {
		t2s = append(t2s, fmt.Sprintf("SELECT %s FROM dual", strings.Join(phs, ",")))
	}
	t2 := strings.Join(t2s, " UNION ALL ")

	sqlTemp := "MERGE INTO " + metadata.QuoteIdentifier(tableName) + " T1 USING (" + t2 + ") T2 ON " + strings.Join(caseSqls, " OR ")
	sqlTemp += "WHEN NOT MATCHED THEN INSERT (" + strings.Join(insertCols, ",") + ") VALUES (" + strings.Join(insertVals, ",") + ")"
	sqlTemp += "WHEN MATCHED THEN UPDATE SET " + strings.Join(upds, ",")

	// 把二维数组转为一维数组
	var args []any
	for _, v := range values {
		args = append(args, v...)
	}

	return dd.dc.TxExec(tx, sqlTemp, args...)
}

func (dd *DMDialect) CopyTable(copy *dbi.DbCopyTable) error {
	tableName := copy.TableName
	metadata := dd.dc.GetMetaData()
	ddl, err := metadata.GetTableDDL(tableName)
	if err != nil {
		return err
	}
	// 生成新表名,为老表明+_copy_时间戳
	newTableName := tableName + "_copy_" + time.Now().Format("20060102150405")

	// 替换新表名
	ddl = strings.ReplaceAll(ddl, fmt.Sprintf("\"%s\"", strings.ToUpper(tableName)), fmt.Sprintf("\"%s\"", strings.ToUpper(newTableName)))
	// 去除空格换行
	ddl = stringx.TrimSpaceAndBr(ddl)
	sqls, err := sqlparser.SplitStatementToPieces(ddl, sqlparser.WithDialect(dd.dc.GetMetaData().SqlParserDialect()))
	for _, sql := range sqls {
		_, _ = dd.dc.Exec(sql)
	}

	// 复制数据
	if copy.CopyData {
		go func() {
			// 设置允许填充自增列之后，显示指定列名可以插入自增列\
			identityInsert := fmt.Sprintf("set identity_insert \"%s\" on", newTableName)
			// 获取列名
			columns, _ := metadata.GetColumns(tableName)
			columnArr := make([]string, 0)
			for _, column := range columns {
				columnArr = append(columnArr, fmt.Sprintf("\"%s\"", column.ColumnName))
			}
			columnStr := strings.Join(columnArr, ",")
			// 插入新数据并显示指定列
			_, _ = dd.dc.Exec(fmt.Sprintf("%s insert into \"%s\" (%s) select %s from \"%s\"", identityInsert, newTableName, columnStr, columnStr, tableName))

		}()
	}
	return err
}

func (dd *DMDialect) ToCommonColumn(dialectColumn *dbi.Column) {
	// 翻译为通用数据库类型
	dataType := dialectColumn.DataType
	t1 := commonColumnTypeMap[string(dataType)]
	if t1 == "" {
		dialectColumn.DataType = dbi.CommonTypeVarchar
		dialectColumn.CharMaxLength = 2000
	} else {
		dialectColumn.DataType = t1
	}
}

func (dd *DMDialect) ToColumn(commonColumn *dbi.Column) {
	ctype := dmColumnTypeMap[commonColumn.DataType]

	if ctype == "" {
		commonColumn.DataType = "VARCHAR"
		commonColumn.CharMaxLength = 2000
	} else {
		commonColumn.DataType = dbi.ColumnDataType(ctype)
		// 如果是date，不设长度
		if collx.ArrayAnyMatches([]string{"date", "time"}, strings.ToLower(ctype)) {
			commonColumn.CharMaxLength = 0
			commonColumn.NumPrecision = 0
		} else
		// 如果是char且长度未设置，则默认长度2000
		if collx.ArrayAnyMatches([]string{"char"}, strings.ToLower(ctype)) && commonColumn.CharMaxLength == 0 {
			commonColumn.CharMaxLength = 2000
		}
	}
}

func (dd *DMDialect) CreateTable(columns []dbi.Column, tableInfo dbi.Table, dropOldTable bool) (int, error) {

	sqlArr := dd.dc.GetMetaData().GenerateTableDDL(columns, tableInfo, dropOldTable)
	// 达梦需要分开执行sql
	if len(sqlArr) > 0 {
		for _, sqlStr := range sqlArr {
			_, err := dd.dc.Exec(sqlStr)
			if err != nil {
				return 0, err
			}
		}
	}

	return len(sqlArr), nil
}

func (dd *DMDialect) CreateIndex(tableInfo dbi.Table, indexs []dbi.Index) error {
	sqls := dd.dc.GetMetaData().GenerateIndexDDL(indexs, tableInfo)
	_, err := dd.dc.Exec(strings.Join(sqls, ";"))
	return err
}

func (dd *DMDialect) UpdateSequence(tableName string, columns []dbi.Column) {

}