package postgres

import (
	"fmt"
	"mayfly-go/internal/db/dbm/dbi"
	"mayfly-go/pkg/errorx"
	"mayfly-go/pkg/utils/anyx"
	"mayfly-go/pkg/utils/collx"
	"strings"
)

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"
	PGSQL_TABLE_DDL_KEY  = "PGSQL_TABLE_DDL_FUNC"
)

type PgsqlMetaData struct {
	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: anyx.ConvString(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, anyx.ConvString(re["dbname"]))
	}

	return databases, nil
}

// 获取表基础元信息, 如表名等
func (pd *PgsqlMetaData) GetTables() ([]dbi.Table, error) {
	_, res, err := pd.dc.Query(dbi.GetLocalSql(PGSQL_META_FILE, PGSQL_TABLE_INFO_KEY))
	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: anyx.ConvString(re["tableComment"]),
			CreateTime:   anyx.ConvString(re["createTime"]),
			TableRows:    anyx.ConvInt(re["tableRows"]),
			DataLength:   anyx.ConvInt64(re["dataLength"]),
			IndexLength:  anyx.ConvInt64(re["indexLength"]),
		})
	}
	return tables, nil
}

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

	columns := make([]dbi.Column, 0)
	for _, re := range res {
		columns = append(columns, dbi.Column{
			TableName:     anyx.ConvString(re["tableName"]),
			ColumnName:    anyx.ConvString(re["columnName"]),
			ColumnType:    anyx.ConvString(re["columnType"]),
			ColumnComment: anyx.ConvString(re["columnComment"]),
			Nullable:      anyx.ConvString(re["nullable"]),
			IsPrimaryKey:  anyx.ConvInt(re["isPrimaryKey"]) == 1,
			IsIdentity:    anyx.ConvInt(re["isIdentity"]) == 1,
			ColumnDefault: anyx.ConvString(re["columnDefault"]),
			NumScale:      anyx.ConvString(re["numScale"]),
		})
	}
	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:    anyx.ConvString(re["indexName"]),
			ColumnName:   anyx.ConvString(re["columnName"]),
			IndexType:    anyx.ConvString(re["IndexType"]),
			IndexComment: anyx.ConvString(re["indexComment"]),
			IsUnique:     anyx.ConvInt(re["isUnique"]) == 1,
			SeqInIndex:   anyx.ConvInt(re["seqInIndex"]),
		})
	}
	// 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
}

// 获取建表ddl
func (pd *PgsqlMetaData) GetTableDDL(tableName string) (string, error) {
	_, err := pd.dc.Exec(dbi.GetLocalSql(PGSQL_META_FILE, PGSQL_TABLE_DDL_KEY))
	if err != nil {
		return "", err
	}

	ddlSql := fmt.Sprintf("select showcreatetable('%s','%s') as sql", pd.dc.Info.CurrentSchema(), tableName)
	_, res, err := pd.dc.Query(ddlSql)
	if err != nil {
		return "", err
	}

	return res[0]["sql"].(string), 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, anyx.ConvString(re["schemaName"]))
	}
	return schemaNames, nil
}