// timetable.go
package controllers

import (
	"bytes"
	"fmt"
	"html/template"
	"sprechstundentool/models"
)

func GetTimetable(officeHours []models.OfficeHour) (timetable map[models.Date]map[int]models.OfficeHour, slots []int) {
	var fullTimetable = make(map[models.Date]map[int]models.OfficeHour)
	for _, officeHour := range officeHours {
		var slot int = 0
		for minute := 0; minute < officeHour.Duration; minute += models.MinuteGranularity { // find slot id
			_, exists := fullTimetable[models.Date{0, officeHour.Day, officeHour.Hour + (officeHour.Minute+minute)/60, (officeHour.Minute + minute) % 60}]
			if exists {
				_, exists := fullTimetable[models.Date{0, officeHour.Day, officeHour.Hour + (officeHour.Minute+minute)/60, (officeHour.Minute + minute) % 60}][slot]
				if exists {
					slot += 1
					minute = 0
					continue
				}
			} else {
				fullTimetable[models.Date{0, officeHour.Day, officeHour.Hour + (officeHour.Minute+minute)/60, (officeHour.Minute + minute) % 60}] = make(map[int]models.OfficeHour)
			}
		}
		for minute := 0; minute < officeHour.Duration; minute += models.MinuteGranularity { // write officeHour id to timetable
			fullTimetable[models.Date{0, officeHour.Day, officeHour.Hour + (officeHour.Minute+minute)/60, (officeHour.Minute + minute) % 60}][slot] = officeHour
		}
	}
	slots = []int{1, 1, 1, 1, 1}
	for date, _ := range fullTimetable {
		if slots[date.Day] < len(fullTimetable[date]) {
			slots[date.Day] = len(fullTimetable[date])
		}
	}
	timetable = make(map[models.Date]map[int]models.OfficeHour)
	for _, officeHour := range officeHours {
		for slot := 0; slot < slots[officeHour.Date.Day]; slot += 1 {
			if fullTimetable[officeHour.Date][slot] == officeHour {
				timetable[officeHour.Date] = make(map[int]models.OfficeHour)
				timetable[officeHour.Date][slot] = officeHour
			}
		}
	}
	return fullTimetable, slots
}

func printTimetable(timetable map[models.Date]map[int]models.OfficeHour, slots []int) template.HTML {
	var tableBody string

	tableCell, _ := template.ParseFiles("templates/td.html")
	for hour := 8; hour < 19; hour += 1 {
		for minute := 0; minute < 60; minute += models.MinuteGranularity {
			tableBody += "<tr>"
			if minute == 0 {
				tableBody += fmt.Sprintf("<td>%d Uhr</td>\n", hour)
			} else {
				tableBody += "<td></td>\n"
			}
			for day := 0; day < 5; day += 1 {
				for slot := 0; slot < slots[day]; slot += 1 {
					current, currentExists := timetable[models.Date{0, day, hour, minute}][slot]

					if currentExists { // This slot is taken by some office hour
						var continued bool = false // is this slot occupied by the same office hour the previous minute?
						var predecessorExists bool
						var predecessor models.OfficeHour
						if hour > 0 && minute < models.MinuteGranularity {
							predecessor, predecessorExists = timetable[models.Date{0, day, hour - 1, 60 - models.MinuteGranularity}][slot]
						} else {
							predecessor, predecessorExists = timetable[models.Date{0, day, hour, minute - models.MinuteGranularity}][slot]
						}
						if predecessorExists {
							continued = (predecessor == current)
						} else {
							continued = false
						}
						if continued {
							continue
						} else {
							var celldata bytes.Buffer
							data := struct {
								Rowspan     int
								StartHour   int
								StartMinute int
								EndHour     int
								EndMinute   int
								CourseName  string
								TutorName   string
								RoomName    string
							}{current.Duration / models.MinuteGranularity,
								current.Hour,
								current.Minute,
								current.Hour + ((current.Minute + current.Duration) / 60),
								(current.Minute + current.Duration) % 60,
								template.HTMLEscapeString(current.Course.Name),
								current.Tutor.Name,
								current.Room.Name,
							}
							tableCell.Execute(&celldata, data)
							tableBody += celldata.String()
						}
					} else {
						if slot+1 == slots[day] {
							tableBody += "<td style=\"border-right: 1px dotted\"></td>\n"
						} else {
							tableBody += "<td></td>\n"
						}
					}
				}
			}
			tableBody += "</tr>\n"
		}
	}
	var table bytes.Buffer
	tableTemplate, _ := template.ParseFiles("templates/officeHourTable.html")

	tableData := struct {
		ColspanMon int
		ColspanTue int
		ColspanWed int
		ColspanThu int
		ColspanFri int
		TableBody  template.HTML
	}{
		slots[0],
		slots[1],
		slots[2],
		slots[3],
		slots[4],
		template.HTML(tableBody),
	}
	tableTemplate.Execute(&table, tableData)
	return template.HTML(table.String())
}