package ical

import (
	"htwkalender/model"
	"htwkalender/service/functions"
	"htwkalender/service/names"
	"time"

	"github.com/jordic/goics"
)

// IcalModel local type for EmitICal function
type IcalModel struct {
	Events  model.Events
	Mapping map[string]model.FeedCollection
}

// EmitICal implements the interface for goics
func (icalModel IcalModel) EmitICal() goics.Componenter {
	europeTime, _ := time.LoadLocation("Europe/Berlin")
	c := goics.NewComponent()
	c.SetType("VCALENDAR")
	c.AddProperty("VERSION", "2.0")
	c.AddProperty("CALSCAL", "GREGORIAN")
	c.AddProperty("TZID", "Europe/Berlin")
	c.AddProperty("X-WR-CALNAME", "HTWK Kalender")
	c.AddProperty("X-WR-TIMEZONE", "Europe/Berlin")
	c.AddProperty("X-LIC-LOCATION", "Europe/Berlin")
	for _, event := range icalModel.Events {
		mapEntry, mappingFound := icalModel.Mapping[event.UUID]

		s := goics.NewComponent()
		s.SetType("VEVENT")
		k, v := goics.FormatDateTime("DTEND;TZID=Europe/Berlin", event.End.Time().Local().In(europeTime))
		s.AddProperty(k, v)
		k, v = goics.FormatDateTime("DTSTART;TZID=Europe/Berlin", event.Start.Time().Local().In(europeTime))
		s.AddProperty(k, v)

		if mappingFound {
			addPropertyIfNotEmpty(s, "SUMMARY", replaceNameIfUserDefined(&event, mapEntry))
			addAlarmIfSpecified(s, event, mapEntry)
		} else {
			addPropertyIfNotEmpty(s, "SUMMARY", event.Name)
		}

		addPropertyIfNotEmpty(s, "DESCRIPTION", generateDescription(event))
		addPropertyIfNotEmpty(s, "LOCATION", event.Rooms)
		c.AddComponent(s)
	}
	return c
}

// if reminder is specified in the configuration for this event, an alarm will be added to the event
func addAlarmIfSpecified(s *goics.Component, event model.Event, mapping model.FeedCollection) {
	if mapping.Reminder {
		a := goics.NewComponent()
		a.SetType("VALARM")
		a.AddProperty("TRIGGER", "-PT15M")
		a.AddProperty("ACTION", "DISPLAY")
		a.AddProperty("DESCRIPTION", "Next course: "+replaceNameIfUserDefined(&event, mapping)+" in "+event.Rooms)
		s.AddComponent(a)
	}
}

// replaceNameIfUserDefined replaces the name of the event with the user defined name if it is not empty
// all contained template strings will be replaced with the corresponding values from the event
func replaceNameIfUserDefined(event *model.Event, mapping model.FeedCollection) string {
	if !functions.OnlyWhitespace(mapping.UserDefinedName) {
		return names.ReplaceTemplateSubStrings(mapping.UserDefinedName, *event)
	}

	return event.Name
}

// AddPropertyIfNotEmpty adds a property to the component if the value is not empty
// or contains only whitespaces
func addPropertyIfNotEmpty(component *goics.Component, key string, value string) {
	if !functions.OnlyWhitespace(value) {
		component.AddProperty(key, value)
	}
}

func generateDescription(event model.Event) string {
	var description string

	if !functions.OnlyWhitespace(event.Notes) {
		description += "Notizen: " + event.Notes + "\n"
	}
	if !functions.OnlyWhitespace(event.Prof) {
		description += "Prof: " + event.Prof + "\n"
	}
	if !functions.OnlyWhitespace(event.Course) {
		description += "Gruppe: " + event.Course + "\n"
	}
	if !functions.OnlyWhitespace(event.EventType) {
		description += "Typ: " + event.EventType + event.Compulsory + "\n"
	}

	return description
}