package glance

import (
	"errors"
	"html/template"
	"time"
)

var calendarWidgetTemplate = mustParseTemplate("calendar.html", "widget-base.html")

var calendarWeekdaysToInt = map[string]time.Weekday{
	"sunday":    time.Sunday,
	"monday":    time.Monday,
	"tuesday":   time.Tuesday,
	"wednesday": time.Wednesday,
	"thursday":  time.Thursday,
	"friday":    time.Friday,
	"saturday":  time.Saturday,
}

type calendarWidget struct {
	widgetBase     `yaml:",inline"`
	FirstDayOfWeek string        `yaml:"first-day-of-week"`
	FirstDay       int           `yaml:"-"`
	cachedHTML     template.HTML `yaml:"-"`
}

func (widget *calendarWidget) initialize() error {
	widget.withTitle("Calendar").withError(nil)

	if widget.FirstDayOfWeek == "" {
		widget.FirstDayOfWeek = "monday"
	} else if _, ok := calendarWeekdaysToInt[widget.FirstDayOfWeek]; !ok {
		return errors.New("invalid first day of week")
	}

	widget.FirstDay = int(calendarWeekdaysToInt[widget.FirstDayOfWeek])
	widget.cachedHTML = widget.renderTemplate(widget, calendarWidgetTemplate)

	return nil
}

func (widget *calendarWidget) Render() template.HTML {
	return widget.cachedHTML
}