package postgres

import (
	"fmt"
	"io"
	"mayfly-go/internal/db/dbm/dbi"
	"mayfly-go/pkg/errorx"
	"mayfly-go/pkg/logx"
	"mayfly-go/pkg/utils/collx"
	"mayfly-go/pkg/utils/stringx"
	"strings"

	"github.com/may-fly/cast"
)

const (
	PGSQL_META_FILE      = "metasql/pgsql_meta.sql"
	PGSQL_DB_SCHEMAS     = "PGSQL_DB_SCHEMAS"
	PGSQL_TABLE_INFO_KEY = "PGSQL_TABLE_INFO"
	PGSQL_INDEX_INFO_KEY = "PGSQL_INDEX_INFO"
	PGSQL_COLUMN_MA_KEY  = "PGSQL_COLUMN_MA"
)

type PgsqlMetaData struct {
	dbi.DefaultMetaData

	dc *dbi.DbConn
}

func (pd *PgsqlMetaData) GetDbServer() (*dbi.DbServer, error) {
	_, res, err := pd.dc.Query("SELECT version() as server_version")
	if err != nil {
		return nil, err
	}
	ds := &dbi.DbServer{
		Version: cast.ToString(res[0]["server_version"]),
	}
	return ds, nil
}

func (pd *PgsqlMetaData) GetDbNames() ([]string, error) {
	_, res, err := pd.dc.Query("SELECT datname AS dbname FROM pg_database WHERE datistemplate = false AND has_database_privilege(datname, 'CONNECT')")
	if err != nil {
		return nil, err
	}

	databases := make([]string, 0)
	for _, re := range res {
		databases = append(databases, cast.ToString(re["dbname"]))
	}

	return databases, nil
}

func (pd *PgsqlMetaData) GetTables(tableNames ...string) ([]dbi.Table, error) {
	meta := pd.dc.GetMetaData()
	names := strings.Join(collx.ArrayMap[string, string](tableNames, func(val string) string {
		return fmt.Sprintf("'%s'", meta.RemoveQuote(val))
	}), ",")

	var res []map[string]any
	var err error

	sql, err := stringx.TemplateParse(dbi.GetLocalSql(PGSQL_META_FILE, PGSQL_TABLE_INFO_KEY), collx.M{"tableNames": names})
	if err != nil {
		return nil, err
	}

	_, res, err = pd.dc.Query(sql)
	if err != nil {
		return nil, err
	}

	tables := make([]dbi.Table, 0)
	for _, re := range res {
		tables = append(tables, dbi.Table{
			TableName:    re["tableName"].(string),
			TableComment: cast.ToString(re["tableComment"]),
			CreateTime:   cast.ToString(re["createTime"]),
			TableRows:    cast.ToInt(re["tableRows"]),
			DataLength:   cast.ToInt64(re["dataLength"]),
			IndexLength:  cast.ToInt64(re["indexLength"]),
		})
	}
	return tables, nil
}

// 获取列元信息, 如列名等
func (pd *PgsqlMetaData) GetColumns(tableNames ...string) ([]dbi.Column, error) {
	meta := pd.dc.GetMetaData()
	tableName := strings.Join(collx.ArrayMap[string, string](tableNames, func(val string) string {
		return fmt.Sprintf("'%s'", meta.RemoveQuote(val))
	}), ",")

	_, res, err := pd.dc.Query(fmt.Sprintf(dbi.GetLocalSql(PGSQL_META_FILE, PGSQL_COLUMN_MA_KEY), tableName))
	if err != nil {
		return nil, err
	}

	columnHelper := meta.GetColumnHelper()
	columns := make([]dbi.Column, 0)
	for _, re := range res {
		column := dbi.Column{
			TableName:     cast.ToString(re["tableName"]),
			ColumnName:    cast.ToString(re["columnName"]),
			DataType:      dbi.ColumnDataType(cast.ToString(re["dataType"])),
			CharMaxLength: cast.ToInt(re["charMaxLength"]),
			ColumnComment: cast.ToString(re["columnComment"]),
			Nullable:      cast.ToString(re["nullable"]) == "YES",
			IsPrimaryKey:  cast.ToInt(re["isPrimaryKey"]) == 1,
			IsIdentity:    cast.ToInt(re["isIdentity"]) == 1,
			ColumnDefault: cast.ToString(re["columnDefault"]),
			NumPrecision:  cast.ToInt(re["numPrecision"]),
			NumScale:      cast.ToInt(re["numScale"]),
		}
		columnHelper.FixColumn(&column)
		columns = append(columns, column)
	}
	return columns, nil
}

func (pd *PgsqlMetaData) GetPrimaryKey(tablename string) (string, error) {
	columns, err := pd.GetColumns(tablename)
	if err != nil {
		return "", err
	}
	if len(columns) == 0 {
		return "", errorx.NewBiz("[%s] 表不存在", tablename)
	}
	for _, v := range columns {
		if v.IsPrimaryKey {
			return v.ColumnName, nil
		}
	}

	return columns[0].ColumnName, nil
}

// 获取表索引信息
func (pd *PgsqlMetaData) GetTableIndex(tableName string) ([]dbi.Index, error) {
	_, res, err := pd.dc.Query(fmt.Sprintf(dbi.GetLocalSql(PGSQL_META_FILE, PGSQL_INDEX_INFO_KEY), tableName))
	if err != nil {
		return nil, err
	}

	indexs := make([]dbi.Index, 0)
	for _, re := range res {
		indexs = append(indexs, dbi.Index{
			IndexName:    cast.ToString(re["indexName"]),
			ColumnName:   cast.ToString(re["columnName"]),
			IndexType:    cast.ToString(re["IndexType"]),
			IndexComment: cast.ToString(re["indexComment"]),
			IsUnique:     cast.ToInt(re["isUnique"]) == 1,
			SeqInIndex:   cast.ToInt(re["seqInIndex"]),
			IsPrimaryKey: cast.ToInt(re["isPrimaryKey"]) == 1,
		})
	}
	// 把查询结果以索引名分组，索引字段以逗号连接
	result := make([]dbi.Index, 0)
	key := ""
	for _, v := range indexs {
		// 当前的索引名
		in := v.IndexName
		if key == in {
			// 索引字段已根据名称和顺序排序，故取最后一个即可
			i := len(result) - 1
			// 同索引字段以逗号连接
			result[i].ColumnName = result[i].ColumnName + "," + v.ColumnName
		} else {
			key = in
			result = append(result, v)
		}
	}
	return result, nil
}

func (pd *PgsqlMetaData) GenerateIndexDDL(indexs []dbi.Index, tableInfo dbi.Table) []string {
	meta := pd.dc.GetMetaData()
	creates := make([]string, 0)
	drops := make([]string, 0)
	comments := make([]string, 0)
	for _, index := range indexs {
		unique := ""
		if index.IsUnique {
			unique = "unique"
		}

		// 如果索引名存在，先删除索引
		drops = append(drops, fmt.Sprintf("drop index if exists %s.%s", pd.dc.Info.CurrentSchema(), index.IndexName))

		// 取出列名，添加引号
		cols := strings.Split(index.ColumnName, ",")
		colNames := make([]string, len(cols))
		for i, name := range cols {
			colNames[i] = meta.QuoteIdentifier(name)
		}
		// 创建索引
		creates = append(creates, fmt.Sprintf("CREATE %s INDEX %s on %s.%s(%s)", unique, meta.QuoteIdentifier(index.IndexName), meta.QuoteIdentifier(pd.dc.Info.CurrentSchema()), meta.QuoteIdentifier(tableInfo.TableName), strings.Join(colNames, ",")))
		if index.IndexComment != "" {
			comment := meta.QuoteEscape(index.IndexComment)
			comments = append(comments, fmt.Sprintf("COMMENT ON INDEX %s.%s IS '%s'", pd.dc.Info.CurrentSchema(), index.IndexName, comment))
		}
	}

	sqlArr := make([]string, 0)

	if len(drops) > 0 {
		sqlArr = append(sqlArr, drops...)
	}

	if len(creates) > 0 {
		sqlArr = append(sqlArr, creates...)
	}
	if len(comments) > 0 {
		sqlArr = append(sqlArr, comments...)
	}
	return sqlArr
}

func (pd *PgsqlMetaData) genColumnBasicSql(column dbi.Column) string {
	meta := pd.dc.GetMetaData()
	colName := meta.QuoteIdentifier(column.ColumnName)
	dataType := string(column.DataType)

	// 如果数据类型是数字，则去掉长度
	if collx.ArrayAnyMatches([]string{"int"}, strings.ToLower(dataType)) {
		column.NumPrecision = 0
		column.CharMaxLength = 0
	}

	// 如果是自增类型，需要转换为serial
	if column.IsIdentity {
		if dataType == "int4" {
			column.DataType = "serial"
		} else if dataType == "int2" {
			column.DataType = "smallserial"
		} else if dataType == "int8" {
			column.DataType = "bigserial"
		} else {
			column.DataType = "bigserial"
		}

		return fmt.Sprintf(" %s %s NOT NULL", colName, column.GetColumnType())
	}

	nullAble := ""
	if !column.Nullable {
		nullAble = " NOT NULL"
	}

	defVal := "" // 默认值需要判断引号，如函数是不需要引号的 // 为了防止跨源函数不支持 当默认值是函数时，不需要设置默认值
	if column.ColumnDefault != "" && !strings.Contains(column.ColumnDefault, "(") {
		mark := false
		// 哪些字段类型默认值需要加引号
		if collx.ArrayAnyMatches([]string{"char", "text", "date", "time", "lob"}, dataType) {
			// 当数据类型是日期时间，默认值是日期时间函数时，默认值不需要引号
			if collx.ArrayAnyMatches([]string{"date", "time"}, strings.ToLower(dataType)) &&
				collx.ArrayAnyMatches([]string{"date", "time"}, strings.ToLower(column.ColumnDefault)) {
				mark = false
			} else {
				mark = true
			}
		}
		// 如果数据类型是日期时间，则写死默认值函数
		if collx.ArrayAnyMatches([]string{"date", "time"}, strings.ToLower(dataType)) {
			column.ColumnDefault = "CURRENT_TIMESTAMP"
		}

		if mark {
			defVal = fmt.Sprintf(" DEFAULT '%s'", column.ColumnDefault)
		} else {
			defVal = fmt.Sprintf(" DEFAULT %s", column.ColumnDefault)
		}
	}

	// 如果是varchar，长度翻倍，防止报错
	if collx.ArrayAnyMatches([]string{"char"}, strings.ToLower(dataType)) {
		column.CharMaxLength = column.CharMaxLength * 2
	}
	columnSql := fmt.Sprintf(" %s %s%s%s", colName, column.GetColumnType(), nullAble, defVal)
	return columnSql
}

func (pd *PgsqlMetaData) GenerateTableDDL(columns []dbi.Column, tableInfo dbi.Table, dropBeforeCreate bool) []string {
	meta := pd.dc.GetMetaData()
	quoteTableName := meta.QuoteIdentifier(tableInfo.TableName)

	sqlArr := make([]string, 0)
	if dropBeforeCreate {
		sqlArr = append(sqlArr, fmt.Sprintf("DROP TABLE IF EXISTS %s", quoteTableName))
	}
	// 组装建表语句
	createSql := fmt.Sprintf("CREATE TABLE %s (\n", quoteTableName)
	fields := make([]string, 0)
	pks := make([]string, 0)
	columnComments := make([]string, 0)
	commentTmp := "comment on column %s.%s is '%s'"

	for _, column := range columns {
		if column.IsPrimaryKey {
			pks = append(pks, meta.QuoteIdentifier(column.ColumnName))
		}

		fields = append(fields, pd.genColumnBasicSql(column))

		// 防止注释内含有特殊字符串导致sql出错
		if column.ColumnComment != "" {
			comment := meta.QuoteEscape(column.ColumnComment)
			columnComments = append(columnComments, fmt.Sprintf(commentTmp, quoteTableName, meta.QuoteIdentifier(column.ColumnName), comment))
		}
	}

	createSql += strings.Join(fields, ",\n")
	if len(pks) > 0 {
		createSql += fmt.Sprintf(", \nPRIMARY KEY (%s)", strings.Join(pks, ","))
	}
	createSql += "\n)"

	tableCommentSql := ""
	if tableInfo.TableComment != "" {
		commentTmp := "comment on table %s is '%s'"
		tableCommentSql = fmt.Sprintf(commentTmp, quoteTableName, meta.QuoteEscape(tableInfo.TableComment))
	}

	// create
	sqlArr = append(sqlArr, createSql)

	// table comment
	if tableCommentSql != "" {
		sqlArr = append(sqlArr, tableCommentSql)
	}
	// column comment
	if len(columnComments) > 0 {
		sqlArr = append(sqlArr, columnComments...)
	}

	return sqlArr
}

// 获取建表ddl
func (pd *PgsqlMetaData) GetTableDDL(tableName string, dropBeforeCreate bool) (string, error) {

	// 1.获取表信息
	tbs, err := pd.GetTables(tableName)
	tableInfo := &dbi.Table{}
	if err != nil || tbs == nil || len(tbs) <= 0 {
		logx.Errorf("获取表信息失败, %s", tableName)
		return "", err
	}
	tableInfo.TableName = tbs[0].TableName
	tableInfo.TableComment = tbs[0].TableComment

	// 2.获取列信息
	columns, err := pd.GetColumns(tableName)
	if err != nil {
		logx.Errorf("获取列信息失败, %s", tableName)
		return "", err
	}
	tableDDLArr := pd.GenerateTableDDL(columns, *tableInfo, dropBeforeCreate)
	// 3.获取索引信息
	indexs, err := pd.GetTableIndex(tableName)
	if err != nil {
		logx.Errorf("获取索引信息失败, %s", tableName)
		return "", err
	}
	// 组装返回
	tableDDLArr = append(tableDDLArr, pd.GenerateIndexDDL(indexs, *tableInfo)...)
	return strings.Join(tableDDLArr, ";\n"), nil
}

// 获取pgsql当前连接的库可访问的schemaNames
func (pd *PgsqlMetaData) GetSchemas() ([]string, error) {
	sql := dbi.GetLocalSql(PGSQL_META_FILE, PGSQL_DB_SCHEMAS)
	_, res, err := pd.dc.Query(sql)
	if err != nil {
		return nil, err
	}
	schemaNames := make([]string, 0)
	for _, re := range res {
		schemaNames = append(schemaNames, cast.ToString(re["schemaName"]))
	}
	return schemaNames, nil
}

func (pd *PgsqlMetaData) DefaultDb() string {
	switch pd.dc.Info.Type {
	case dbi.DbTypePostgres, dbi.DbTypeGauss:
		return "postgres"
	case dbi.DbTypeKingbaseEs:
		return "security"
	case dbi.DbTypeVastbase:
		return "vastbase"
	default:
		return ""
	}
}

func (pd *PgsqlMetaData) AfterDumpInsert(writer io.Writer, tableName string, columns []dbi.Column) {

	// 设置自增序列当前值
	for _, column := range columns {
		if column.IsIdentity {
			seq := fmt.Sprintf("SELECT setval('%s_%s_seq', (SELECT max(%s) FROM %s));\n", tableName, column.ColumnName, column.ColumnName, tableName)
			writer.Write([]byte(seq))
		}
	}

	writer.Write([]byte("COMMIT;\n"))
}

func (pd *PgsqlMetaData) GetDataHelper() dbi.DataHelper {
	return new(DataHelper)
}

func (pd *PgsqlMetaData) GetColumnHelper() dbi.ColumnHelper {
	return new(ColumnHelper)
}

func (pd *PgsqlMetaData) GetDumpHelper() dbi.DumpHelper {
	return new(DumpHelper)
}