package models

import (
	"arbeitszeitmessung/helper"
	"encoding/json"
	"fmt"
	"log"
	"log/slog"
	"sort"
	"time"
)

type WorkDay struct {
	Day               time.Time `json:"day"`
	Bookings          []Booking `json:"bookings"`
	workTime          time.Duration
	pauseTime         time.Duration
	TimeFrom          time.Time
	TimeTo            time.Time
	kurzArbeit        bool
	kurzArbeitAbsence Absence
	// Urlaub untertags
	worktimeAbsece Absence
}

type WorktimeBase string

const (
	WorktimeBaseWeek WorktimeBase = "week"
	WorktimeBaseDay  WorktimeBase = "day"
)

func (d *WorkDay) GetWorktimeAbsence() Absence {
	return d.worktimeAbsece
}

// Gets the time as is in the db (with corrected pause times)
func (d *WorkDay) GetWorktime(u User, base WorktimeBase, includeKurzarbeit bool) time.Duration {
	if includeKurzarbeit && d.IsKurzArbeit() && len(d.Bookings) > 0 {
		return d.kurzArbeitAbsence.GetWorktime(u, base, true)
	}
	work, pause := calcWorkPause(d.Bookings)
	work, pause = correctWorkPause(work, pause)
	if (d.worktimeAbsece != Absence{}) {
		work += d.worktimeAbsece.GetWorktime(u, base, false)
	}
	return work.Round(time.Minute)
}

// Gets the corrected pause times based on db entries
func (d *WorkDay) GetPausetime(u User, base WorktimeBase, includeKurzarbeit bool) time.Duration {
	work, pause := calcWorkPause(d.Bookings)
	work, pause = correctWorkPause(work, pause)
	return pause.Round(time.Minute)
}

// Returns the overtime based on the db entries
func (d *WorkDay) GetOvertime(u User, base WorktimeBase, includeKurzarbeit bool) time.Duration {
	work := d.GetWorktime(u, base, includeKurzarbeit)
	var targetHours time.Duration
	switch base {
	case WorktimeBaseDay:
		targetHours = u.ArbeitszeitProTag()
	case WorktimeBaseWeek:
		targetHours = u.ArbeitszeitProWocheFrac(0.2)
	}
	return (work - targetHours).Round(time.Minute)
}

func (d *WorkDay) GetTimes(u User, base WorktimeBase, includeKurzarbeit bool) (work, pause, overtime time.Duration) {
	return d.GetWorktime(u, base, includeKurzarbeit), d.GetPausetime(u, base, includeKurzarbeit), d.GetOvertime(u, base, includeKurzarbeit)
}

func calcWorkPause(bookings []Booking) (work, pause time.Duration) {
	var lastBooking Booking
	for _, b := range bookings {
		if b.CheckInOut%2 == 1 {
			if !lastBooking.Timestamp.IsZero() {
				pause += b.Timestamp.Sub(lastBooking.Timestamp)
			}
		} else {
			work += b.Timestamp.Sub(lastBooking.Timestamp)
		}
		lastBooking = b
	}
	if len(bookings)%2 == 1 {
		work += time.Since(lastBooking.Timestamp.Local())
	}
	return work, pause
}

func correctWorkPause(workIn, pauseIn time.Duration) (work, pause time.Duration) {
	if workIn <= 6*time.Hour || pauseIn > 45*time.Minute {
		return workIn, pauseIn
	}

	var diff time.Duration
	if workIn <= (9*time.Hour) && pauseIn < 30*time.Minute {
		diff = 30*time.Minute - pauseIn
	} else if pauseIn < 45*time.Minute {
		diff = 45*time.Minute - pauseIn
	}
	work = workIn - diff
	pause = pauseIn + diff
	return work, pause
}

func sortDays(days map[string]IWorkDay, forward bool) []IWorkDay {
	var sortedDays []IWorkDay
	for _, day := range days {
		sortedDays = append(sortedDays, day)
	}
	if forward {
		sort.Slice(sortedDays, func(i, j int) bool {
			return sortedDays[i].Date().After(sortedDays[j].Date())
		})
	} else {
		sort.Slice(sortedDays, func(i, j int) bool {
			return sortedDays[i].Date().Before(sortedDays[j].Date())
		})
	}
	return sortedDays
}

func (d *WorkDay) Date() time.Time {
	return d.Day
}

func (d *WorkDay) GenerateKurzArbeitBookings(u User) (time.Time, time.Time) {
	var timeFrom, timeTo time.Time
	if d.GetWorktime(u, WorktimeBaseDay, false) >= u.ArbeitszeitProTag() {
		return timeFrom, timeTo
	}

	timeFrom = d.Bookings[len(d.Bookings)-1].Timestamp.Add(time.Minute)
	timeTo = timeFrom.Add(u.ArbeitszeitProTag() - d.GetWorktime(u, WorktimeBaseDay, false))
	slog.Debug("Added duration as Kurzarbeit", "date", d.Date().String(), "duration", timeTo.Sub(timeFrom).String())

	return timeFrom, timeTo
}

func (d *WorkDay) GetKurzArbeit() *Absence {
	return &d.kurzArbeitAbsence
}

func (d *WorkDay) ToString() string {
	return fmt.Sprintf("WorkDay: %s with %d bookings and worktime: %s", d.Date().Format(time.DateOnly), len(d.Bookings), helper.FormatDuration(d.workTime))
}

func (d *WorkDay) IsWorkDay() bool {
	return true
}

func (d *WorkDay) SetKurzArbeit(kurzArbeit bool) {
	d.kurzArbeit = kurzArbeit
}

func (d *WorkDay) IsKurzArbeit() bool {
	return d.kurzArbeit
}

func GetWorkDays(user User, tsFrom, tsTo time.Time) []WorkDay {
	var workDays []WorkDay
	var workSec, pauseSec float64

	qStr, err := DB.Prepare(`
	WITH all_days AS (
    	SELECT generate_series($2::DATE, $3::DATE - INTERVAL '1 day', INTERVAL '1 day')::DATE AS work_date),
    ordered_bookings AS (
	    SELECT
	        a.timestamp::DATE AS work_date,
	        a.timestamp,
	        a.check_in_out,
	        a.counter_id,
	        a.anwesenheit_typ,
	        sat.anwesenheit_name AS anwesenheit_typ_name,
	        LAG(a.timestamp) OVER (PARTITION BY a.card_uid, a.timestamp::DATE ORDER BY a.timestamp) AS prev_timestamp,
	        LAG(a.check_in_out) OVER (PARTITION BY a.card_uid, a.timestamp::DATE ORDER BY a.timestamp) AS prev_check
	    FROM anwesenheit a
	    LEFT JOIN s_anwesenheit_typen sat ON a.anwesenheit_typ = sat.anwesenheit_id
	    WHERE a.card_uid = $1
	      AND a.timestamp::DATE >= $2
	      AND a.timestamp::DATE <= $3
	)
	SELECT
	    d.work_date,
	    COALESCE(MIN(b.timestamp), NOW()) AS time_from,
	    COALESCE(MAX(b.timestamp), NOW()) AS time_to,
	    COALESCE(
	        EXTRACT(EPOCH FROM SUM(
	            CASE
	                WHEN b.prev_check IN (1, 3) AND b.check_in_out IN (2, 4, 254)
	                THEN b.timestamp - b.prev_timestamp
	                ELSE INTERVAL '0'
	            END
	        )), 0
	    ) AS total_work_seconds,
	    COALESCE(
	        EXTRACT(EPOCH FROM SUM(
	            CASE
	                WHEN b.prev_check IN (2, 4, 254) AND b.check_in_out IN (1, 3)
	                THEN b.timestamp - b.prev_timestamp
	                ELSE INTERVAL '0'
	            END
	        )), 0
	    ) AS total_pause_seconds,
	    COALESCE(jsonb_agg(jsonb_build_object(
	        'check_in_out', b.check_in_out,
	        'timestamp', b.timestamp,
	        'counter_id', b.counter_id,
	        'anwesenheit_typ', b.anwesenheit_typ,
	        'anwesenheit_typ', jsonb_build_object(
	            'anwesenheit_id', b.anwesenheit_typ,
	            'anwesenheit_name', b.anwesenheit_typ_name
	        )
	    ) ORDER BY b.timestamp), '[]'::jsonb) AS bookings
	FROM all_days d
	LEFT JOIN ordered_bookings b ON d.work_date = b.work_date
	GROUP BY d.work_date
	ORDER BY d.work_date ASC;`)

	if err != nil {
		log.Println("Error preparing SQL statement", err)
		return workDays
	}

	defer qStr.Close()
	rows, err := qStr.Query(user.CardUID, tsFrom, tsTo)
	if err != nil {
		log.Println("Error getting rows!")
		return workDays
	}
	defer rows.Close()
	for rows.Next() {
		var workDay WorkDay
		var bookings []byte
		if err := rows.Scan(&workDay.Day, &workDay.TimeFrom, &workDay.TimeTo, &workSec, &pauseSec, &bookings); err != nil {
			log.Println("Error scanning row!", err)
			return workDays
		}
		workDay.workTime = time.Duration(workSec * float64(time.Second))
		workDay.pauseTime = time.Duration(pauseSec * float64(time.Second))
		err = json.Unmarshal(bookings, &workDay.Bookings)
		if err != nil {
			log.Println("Error parsing bookings JSON!", err)
			return nil
		}
		// better empty day handling
		if len(workDay.Bookings) == 1 && workDay.Bookings[0].CounterId == 0 {
			workDay.Bookings = []Booking{}
		}
		if len(workDay.Bookings) > 1 || !helper.IsWeekend(workDay.Date()) {
			workDays = append(workDays, workDay)
		}
	}
	if err = rows.Err(); err != nil {
		log.Println("Error in workday rows!", err)
		return workDays
	}
	return workDays
}

// returns bool wheter the workday was ended with an automatic logout
func (d *WorkDay) RequiresAction() bool {
	if len(d.Bookings) == 0 {
		return false
	}
	return d.Bookings[len(d.Bookings)-1].CheckInOut == 254
}

func (d *WorkDay) GetDayProgress(u User) int8 {
	if d.RequiresAction() {
		return -1
	}
	workTime := d.GetWorktime(u, WorktimeBaseDay, true)
	progress := (workTime.Seconds() / u.ArbeitszeitProTag().Seconds()) * 100
	return int8(progress)
}