// Copyright 2013 The XORM Authors. All rights reserved.
// Use of this source code is governed by a BSD
// license that can be found in the LICENSE file.

// Package xorm provides is a simple and powerful ORM for Go. It makes your
// database operation simple.

package xorm

import (
	"database/sql"
	"fmt"
	"io"
	"reflect"
	"strconv"
	"strings"
	"sync"
)

const (
	POSTGRES = "postgres"
	SQLITE   = "sqlite3"
	MYSQL    = "mysql"
	MYMYSQL  = "mymysql"
)

type dialect interface {
	SqlType(t *Column) string
	SupportInsertMany() bool
	QuoteStr() string
	AutoIncrStr() string
	SupportEngine() bool
	SupportCharset() bool
}

type Engine struct {
	Mapper         IMapper
	TagIdentifier  string
	DriverName     string
	DataSourceName string
	Dialect        dialect
	Tables         map[reflect.Type]*Table
	mutex          *sync.Mutex
	ShowSQL        bool
	pool           IConnectPool
	CacheMapping   bool
	Filters        []Filter
	Logger         io.Writer
}

func (engine *Engine) SupportInsertMany() bool {
	return engine.Dialect.SupportInsertMany()
}

func (engine *Engine) QuoteStr() string {
	return engine.Dialect.QuoteStr()
}

func (engine *Engine) Quote(sql string) string {
	return engine.Dialect.QuoteStr() + sql + engine.Dialect.QuoteStr()
}

func (engine *Engine) SqlType(c *Column) string {
	return engine.Dialect.SqlType(c)
}

func (engine *Engine) AutoIncrStr() string {
	return engine.Dialect.AutoIncrStr()
}

func (engine *Engine) SetPool(pool IConnectPool) error {
	engine.pool = pool
	return engine.pool.Init(engine)
}

func Type(bean interface{}) reflect.Type {
	sliceValue := reflect.Indirect(reflect.ValueOf(bean))
	return reflect.TypeOf(sliceValue.Interface())
}

func StructName(v reflect.Type) string {
	for v.Kind() == reflect.Ptr {
		v = v.Elem()
	}
	return v.Name()
}

func (e *Engine) OpenDB() (*sql.DB, error) {
	return sql.Open(e.DriverName, e.DataSourceName)
}

func (engine *Engine) NewSession() *Session {
	session := &Session{Engine: engine}
	session.Init()
	return session
}

func (engine *Engine) Close() error {
	return engine.pool.Close(engine)
}

func (engine *Engine) Test() error {
	session := engine.NewSession()
	defer session.Close()
	engine.LogSQL("PING DATABASE", engine.DriverName)
	return session.Ping()
}

func (engine *Engine) LogSQL(contents ...interface{}) {
	if engine.ShowSQL {
		io.WriteString(engine.Logger, fmt.Sprintln(contents...))
	}
}

func (engine *Engine) LogError(contents ...interface{}) {
	io.WriteString(engine.Logger, fmt.Sprintln(contents...))
}

func (engine *Engine) Sql(querystring string, args ...interface{}) *Session {
	session := engine.NewSession()
	return session.Sql(querystring, args...)
}

func (engine *Engine) Cascade(trueOrFalse ...bool) *Session {
	session := engine.NewSession()
	return session.Cascade(trueOrFalse...)
}

func (engine *Engine) Where(querystring string, args ...interface{}) *Session {
	session := engine.NewSession()
	return session.Where(querystring, args...)
}

func (engine *Engine) Id(id int64) *Session {
	session := engine.NewSession()
	return session.Id(id)
}

func (engine *Engine) Charset(charset string) *Session {
	session := engine.NewSession()
	return session.Charset(charset)
}

func (engine *Engine) StoreEngine(storeEngine string) *Session {
	session := engine.NewSession()
	return session.StoreEngine(storeEngine)
}

func (engine *Engine) Cols(columns ...string) *Session {
	session := engine.NewSession()
	return session.Cols(columns...)
}

func (engine *Engine) Trans(t string) *Session {
	session := engine.NewSession()
	return session.Trans(t)
}

func (engine *Engine) In(column string, args ...interface{}) *Session {
	session := engine.NewSession()
	return session.In(column, args...)
}

func (engine *Engine) Table(tableNameOrBean interface{}) *Session {
	session := engine.NewSession()
	return session.Table(tableNameOrBean)
}

func (engine *Engine) Limit(limit int, start ...int) *Session {
	session := engine.NewSession()
	return session.Limit(limit, start...)
}

func (engine *Engine) OrderBy(order string) *Session {
	session := engine.NewSession()
	return session.OrderBy(order)
}

//The join_operator should be one of INNER, LEFT OUTER, CROSS etc - this will be prepended to JOIN
func (engine *Engine) Join(join_operator, tablename, condition string) *Session {
	session := engine.NewSession()
	return session.Join(join_operator, tablename, condition)
}

func (engine *Engine) GroupBy(keys string) *Session {
	session := engine.NewSession()
	return session.GroupBy(keys)
}

func (engine *Engine) Having(conditions string) *Session {
	session := engine.NewSession()
	return session.Having(conditions)
}

// some lock needed
func (engine *Engine) AutoMapType(t reflect.Type) *Table {
	engine.mutex.Lock()
	defer engine.mutex.Unlock()
	table, ok := engine.Tables[t]
	if !ok {
		table = engine.MapType(t)
		engine.Tables[t] = table
	}
	return table
}

func (engine *Engine) AutoMap(bean interface{}) *Table {
	t := Type(bean)
	return engine.AutoMapType(t)
}

func (engine *Engine) MapType(t reflect.Type) *Table {
	table := &Table{Name: engine.Mapper.Obj2Table(t.Name()), Type: t,
		Indexes: map[string][]string{}, Uniques: map[string][]string{}}
	table.Columns = make(map[string]*Column)
	var idFieldColName string

	for i := 0; i < t.NumField(); i++ {
		tag := t.Field(i).Tag
		ormTagStr := tag.Get(engine.TagIdentifier)
		var col *Column
		fieldType := t.Field(i).Type

		if ormTagStr != "" {
			col = &Column{FieldName: t.Field(i).Name, Nullable: true, IsPrimaryKey: false,
				IsAutoIncrement: false, MapType: TWOSIDES}
			tags := strings.Split(ormTagStr, " ")

			if len(tags) > 0 {
				if tags[0] == "-" {
					continue
				}
				if (strings.ToUpper(tags[0]) == "EXTENDS") &&
					(fieldType.Kind() == reflect.Struct) {
					parentTable := engine.MapType(fieldType)
					for name, col := range parentTable.Columns {
						col.FieldName = fmt.Sprintf("%v.%v", fieldType.Name(), col.FieldName)
						table.Columns[name] = col
					}

					table.PrimaryKey = parentTable.PrimaryKey
					continue
				}
				for j, key := range tags {
					k := strings.ToUpper(key)
					switch {
					case k == "<-":
						col.MapType = ONLYFROMDB
					case k == "->":
						col.MapType = ONLYTODB
					case k == "PK":
						col.IsPrimaryKey = true
						col.Nullable = false
						table.PrimaryKey = col.Name
					case k == "NULL":
						col.Nullable = (strings.ToUpper(tags[j-1]) != "NOT")
					case k == "AUTOINCR":
						col.IsAutoIncrement = true
					case k == "DEFAULT":
						col.Default = tags[j+1]
					case strings.HasPrefix(k, "INDEX"):
						if k == "INDEX" {
							col.IndexName = ""
							col.IndexType = SINGLEINDEX
						} else {
							col.IndexName = k[len("INDEX")+1 : len(k)-1]
							col.IndexType = UNIONINDEX
						}
					case strings.HasPrefix(k, "UNIQUE"):
						if k == "UNIQUE" {
							col.UniqueName = ""
							col.UniqueType = SINGLEUNIQUE
						} else {
							col.UniqueName = k[len("UNIQUE")+1 : len(k)-1]
							col.UniqueType = UNIONUNIQUE
						}
					case k == "NOT":
					default:
						if strings.Contains(k, "(") && strings.HasSuffix(k, ")") {
							fs := strings.Split(k, "(")
							if _, ok := sqlTypes[fs[0]]; !ok {
								continue
							}
							col.SQLType = SQLType{fs[0], 0, 0}
							fs2 := strings.Split(fs[1][0:len(fs[1])-1], ",")
							if len(fs2) == 2 {
								col.Length, _ = strconv.Atoi(fs2[0])
								col.Length2, _ = strconv.Atoi(fs2[1])
							} else if len(fs2) == 1 {
								col.Length, _ = strconv.Atoi(fs2[0])
							}
						} else {
							if _, ok := sqlTypes[k]; ok {
								col.SQLType = SQLType{k, 0, 0}
							} else if k != col.Default {
								col.Name = key
							}
						}
						engine.SqlType(col)
					}
				}
				if col.SQLType.Name == "" {
					col.SQLType = Type2SQLType(fieldType)
				}

				if col.Length == 0 {
					col.Length = col.SQLType.DefaultLength
				}
				if col.Length2 == 0 {
					col.Length2 = col.SQLType.DefaultLength2
				}

				if col.Name == "" {
					col.Name = engine.Mapper.Obj2Table(t.Field(i).Name)
				}
				if col.IndexType == SINGLEINDEX {
					col.IndexName = col.Name
					table.Indexes[col.IndexName] = []string{col.Name}
				} else if col.IndexType == UNIONINDEX {
					if unionIdxes, ok := table.Indexes[col.IndexName]; ok {
						table.Indexes[col.IndexName] = append(unionIdxes, col.Name)
					} else {
						table.Indexes[col.IndexName] = []string{col.Name}
					}
				}

				if col.UniqueType == SINGLEUNIQUE {
					col.UniqueName = col.Name
					table.Uniques[col.UniqueName] = []string{col.Name}
				} else if col.UniqueType == UNIONUNIQUE {
					if unionUniques, ok := table.Uniques[col.UniqueName]; ok {
						table.Uniques[col.UniqueName] = append(unionUniques, col.Name)
					} else {
						table.Uniques[col.UniqueName] = []string{col.Name}
					}
				}
			}
		} else {
			sqlType := Type2SQLType(fieldType)
			col = &Column{engine.Mapper.Obj2Table(t.Field(i).Name), t.Field(i).Name, sqlType,
				sqlType.DefaultLength, sqlType.DefaultLength2, true, "", NONEUNIQUE, "", NONEINDEX, "", false, false, TWOSIDES}

		}
		if col.IsAutoIncrement {
			col.Nullable = false
		}
		if col.IsPrimaryKey {
			table.PrimaryKey = col.Name
		}
		table.Columns[col.Name] = col
		if col.FieldName == "Id" || strings.HasSuffix(col.FieldName, ".Id") {
			idFieldColName = col.Name
		}
	}

	if idFieldColName != "" && table.PrimaryKey == "" {
		col := table.Columns[idFieldColName]
		col.IsPrimaryKey = true
		col.IsAutoIncrement = true
		col.Nullable = false
		table.PrimaryKey = col.Name
	}

	return table
}

// Map should use after all operation because it's not thread safe
func (engine *Engine) Map(beans ...interface{}) (e error) {
	engine.mutex.Lock()
	defer engine.mutex.Unlock()
	for _, bean := range beans {
		t := Type(bean)
		engine.Tables[t] = engine.MapType(t)
	}
	return
}

func (engine *Engine) UnMap(beans ...interface{}) (e error) {
	engine.mutex.Lock()
	defer engine.mutex.Unlock()
	for _, bean := range beans {
		t := Type(bean)
		if _, ok := engine.Tables[t]; ok {
			delete(engine.Tables, t)
		}
	}
	return
}

func (e *Engine) DropAll() error {
	session := e.NewSession()
	defer session.Close()

	err := session.Begin()
	if err != nil {
		return err
	}
	err = session.DropAll()
	if err != nil {
		session.Rollback()
		return err
	}
	return session.Commit()
}

func (e *Engine) CreateTables(beans ...interface{}) error {
	session := e.NewSession()
	err := session.Begin()
	defer session.Close()
	if err != nil {
		return err
	}

	for _, bean := range beans {
		err = session.CreateTable(bean)
		if err != nil {
			session.Rollback()
			return err
		}
	}
	return session.Commit()
}

func (e *Engine) DropTables(beans ...interface{}) error {
	session := e.NewSession()
	err := session.Begin()
	defer session.Close()
	if err != nil {
		return err
	}

	for _, bean := range beans {
		err = session.DropTable(bean)
		if err != nil {
			session.Rollback()
			return err
		}
	}
	return session.Commit()
}

func (e *Engine) CreateAll() error {
	session := e.NewSession()
	defer session.Close()
	return session.CreateAll()
}

func (engine *Engine) Exec(sql string, args ...interface{}) (sql.Result, error) {
	session := engine.NewSession()
	defer session.Close()
	return session.Exec(sql, args...)
}

func (engine *Engine) Query(sql string, paramStr ...interface{}) (resultsSlice []map[string][]byte, err error) {
	session := engine.NewSession()
	defer session.Close()
	return session.Query(sql, paramStr...)
}

func (engine *Engine) Insert(beans ...interface{}) (int64, error) {
	session := engine.NewSession()
	defer session.Close()
	return session.Insert(beans...)
}

func (engine *Engine) InsertOne(bean interface{}) (int64, error) {
	session := engine.NewSession()
	defer session.Close()
	return session.InsertOne(bean)
}

func (engine *Engine) Update(bean interface{}, condiBeans ...interface{}) (int64, error) {
	session := engine.NewSession()
	defer session.Close()
	return session.Update(bean, condiBeans...)
}

func (engine *Engine) Delete(bean interface{}) (int64, error) {
	session := engine.NewSession()
	defer session.Close()
	return session.Delete(bean)
}

func (engine *Engine) Get(bean interface{}) (bool, error) {
	session := engine.NewSession()
	defer session.Close()
	return session.Get(bean)
}

func (engine *Engine) Find(beans interface{}, condiBeans ...interface{}) error {
	session := engine.NewSession()
	defer session.Close()
	return session.Find(beans, condiBeans...)
}

func (engine *Engine) Count(bean interface{}) (int64, error) {
	session := engine.NewSession()
	defer session.Close()
	return session.Count(bean)
}