package apps

import (
	"github.com/jinzhu/gorm"
	_ "github.com/jinzhu/gorm/dialects/sqlite"
)

// AppsProcessor encapsulates functions for apps manipulation
type AppsProcessor struct {
	DB *gorm.DB
}

func (a *AppsProcessor) Init() {
	a.DB.AutoMigrate(Label{})
	a.DB.AutoMigrate(App{})
}

// Get returns one app
func (a *AppsProcessor) Get(name string) (*App, error) {
	var app App

	err := a.DB.Preload("Labels").Where("name = ?", name).First(&app).Error
	if err != nil {
		return nil, err
	}

	return &app, nil
}

// List returns all apps located on this node
func (a *AppsProcessor) List() (*Apps, error) {
	var apps Apps

	err := a.DB.Preload("Labels").Find(&apps).Error
	if err != nil {
		return nil, err
	}

	return &apps, nil
}

// New creates new record about application in the database
func (a *AppsProcessor) New(name string, SSHPort int, HTTPPort int, image string, CPU int, memory int) error {
	app := App{
		Name:     name,
		SSHPort:  SSHPort,
		HTTPPort: HTTPPort,
		Image:    image,
		CPU:      CPU,
		Memory:   memory,
	}

	validationErrors := app.Validate()
	if len(validationErrors) != 0 {
		return ValidationError{
			Errors: validationErrors,
		}
	}

	if err := a.DB.Create(&app).Error; err != nil {
		return err
	}

	return nil
}

// Update changes value about app in the database
func (a *AppsProcessor) Update(name string, SSHPort int, HTTPPort int, image string, CPU int, memory int) (*App, error) {
	var app App

	err := a.DB.Where("name = ?", name).First(&app).Error
	if err != nil {
		return &app, err
	}

	// Update affected fields
	if image != "" {
		app.Image = image
	}

	if CPU != 0 {
		app.CPU = CPU
	}

	if memory != 0 {
		app.Memory = memory
	}

	// SSH port and HTTP port cannot be turned off when they are once set
	if SSHPort != 0 {
		app.SSHPort = SSHPort
	}

	// SSH port and HTTP port cannot be turned off when they are once set
	if HTTPPort != 0 {
		app.HTTPPort = HTTPPort
	}

	validationErrors := app.Validate()
	if len(validationErrors) != 0 {
		return &app, ValidationError{
			Errors: validationErrors,
		}
	}

	// Apply the changes
	err = a.DB.Save(&app).Error
	return &app, err
}

// UpdateResources updates various metrics saved in the database
func (a *AppsProcessor) UpdateResources(name string, state string, CPUUsage float64, memory int, diskUsageBytes int, diskUsageInodes int) error {
	err := a.DB.Model(&App{}).Where("name = ?", name).Updates(App{
		State:           state,
		CPUUsage:        CPUUsage,
		MemoryUsage:     memory,
		DiskUsageBytes:  diskUsageBytes,
		DiskUsageInodes: diskUsageInodes,
	}).Error
	return err
}

// UpdateState sets container's state
func (a *AppsProcessor) UpdateState(name string, state string) error {
	err := a.DB.Model(&App{}).Where("name = ?", name).Updates(App{
		State: state,
	}).Error
	return err
}

// Delete removes records about one app from the database
func (a *AppsProcessor) Delete(name string) error {
	app, err := a.Get(name)
	if err != nil {
		return err
	}

	err = a.DB.Where("app_id = ?", app.ID).Delete(&Label{}).Error
	if err != nil {
		return err
	}

	err = a.DB.Where("id = ?", app.ID).Delete(App{}).Error

	return err
}

// AddLabel adds label to existing application
func (a *AppsProcessor) AddLabel(appName string, label string) error {
	var app App

	err := a.DB.Where("name = ?", appName).First(&app).Error
	if err != nil {
		return err
	}

	// Check if there is such label already
	var count int
	err = a.DB.Model(&Label{}).Where("value = ? AND app_id = ?", label, app.ID).Count(&count).Error
	if err != nil {
		return err
	}

	if count > 0 {
		return nil
	}

	// And create the label
	return a.DB.Create(&Label{AppID: app.ID, Value: label}).Error
}

// RemoveLabel removes label from existing application
func (a *AppsProcessor) RemoveLabel(appName string, label string) error {
	var app App

	err := a.DB.Where("name = ?", appName).First(&app).Error
	if err != nil {
		return err
	}

	return a.DB.Where("label = ? AND app_id = ?", label, app.ID).Delete(&Label{}).Error
}