yasshi2525/RushHour

package services

import (
    "fmt"

    "github.com/yasshi2525/RushHour/entities"
)

// MigrateDB migrate database by reference Meta
// POLICY:
//   1. not allow nullable field because go cann't identify nil or zero value
//      so, no foreign key restriction for nullable field
//   2. id must be grater than 0. id: 0 means nil
//   3. not use sql.NullInst64 for performance
func MigrateDB() {
    foreign := make(map[entities.ModelType]string)

    db.AutoMigrate(&OpLog{})

    // create instance corresponding to each record
    for _, key := range entities.TypeList {
        if !key.IsDB() {
            continue
        }

        proto := key.Obj(Model)
        db.AutoMigrate(proto)

        // foreign key for owner
        if proto.B().O != nil {
            owner := fmt.Sprintf("%s(id)", entities.PLAYER.Table())
            db.Model(proto).AddForeignKey("owner_id", owner, "RESTRICT", "RESTRICT")
        }

        foreign[key] = fmt.Sprintf("%s(id)", key.Table())
    }

    // RailEdge connects RailNode
    db.Model(entities.RAILEDGE.Obj(Model)).AddForeignKey("from_id", foreign[entities.RAILNODE], "CASCADE", "RESTRICT")
    db.Model(entities.RAILEDGE.Obj(Model)).AddForeignKey("to_id", foreign[entities.RAILNODE], "CASCADE", "RESTRICT")

    // Station composes Platforms and Gates
    db.Model(entities.PLATFORM.Obj(Model)).AddForeignKey("rail_node_id", foreign[entities.RAILNODE], "RESTRICT", "RESTRICT")
    db.Model(entities.PLATFORM.Obj(Model)).AddForeignKey("station_id", foreign[entities.STATION], "CASCADE", "RESTRICT")
    db.Model(entities.GATE.Obj(Model)).AddForeignKey("station_id", foreign[entities.STATION], "CASCADE", "RESTRICT")

    // Line composes LineTasks
    db.Model(entities.LINETASK.Obj(Model)).AddForeignKey("rail_line_id", foreign[entities.RAILLINE], "CASCADE", "RESTRICT")

    // Human departs from Residence and destinates to Company
    db.Model(entities.HUMAN.Obj(Model)).AddForeignKey("from_id", foreign[entities.RESIDENCE], "RESTRICT", "RESTRICT")
    db.Model(entities.HUMAN.Obj(Model)).AddForeignKey("to_id", foreign[entities.COMPANY], "RESTRICT", "RESTRICT")
}

// PurgeDB purge database without login user
func PurgeDB(o *entities.Player) {
    length := len(entities.TypeList)
    tx := db.Begin()
    for i := length - 1; i >= 0; i-- {
        if key := entities.TypeList[i]; key.IsDB() {
            if key == entities.PLAYER {
                db.Exec(fmt.Sprintf("DELETE FROM %s WHERE login_id <> %s", key.Table(), o.LoginID))
            } else {
                db.Exec(fmt.Sprintf("DELETE FROM %s", key.Table()))
            }
        }
    }
    tx.Commit()
}