import { CalendarConfig } from '../core/CalendarConfig.js';

/**
 * PositionUtils - Utility funktioner til pixel/minut konvertering
 * Håndterer positionering og størrelse beregninger for calendar events
 */
export class PositionUtils {
    private config: CalendarConfig;

    constructor(config: CalendarConfig) {
        this.config = config;
    }

    /**
     * Konverter minutter til pixels
     */
    public minutesToPixels(minutes: number): number {
        const pixelsPerHour = this.config.get('hourHeight');
        return (minutes / 60) * pixelsPerHour;
    }

    /**
     * Konverter pixels til minutter
     */
    public pixelsToMinutes(pixels: number): number {
        const pixelsPerHour = this.config.get('hourHeight');
        return (pixels / pixelsPerHour) * 60;
    }

    /**
     * Konverter tid (HH:MM) til pixels fra dag start
     */
    public timeToPixels(timeString: string): number {
        const [hours, minutes] = timeString.split(':').map(Number);
        const totalMinutes = (hours * 60) + minutes;
        const dayStartMinutes = this.config.get('dayStartHour') * 60;
        const minutesFromDayStart = totalMinutes - dayStartMinutes;
        
        return this.minutesToPixels(minutesFromDayStart);
    }

    /**
     * Konverter Date object til pixels fra dag start
     */
    public dateToPixels(date: Date): number {
        const hours = date.getHours();
        const minutes = date.getMinutes();
        const totalMinutes = (hours * 60) + minutes;
        const dayStartMinutes = this.config.get('dayStartHour') * 60;
        const minutesFromDayStart = totalMinutes - dayStartMinutes;
        
        return this.minutesToPixels(minutesFromDayStart);
    }

    /**
     * Konverter pixels til tid (HH:MM format)
     */
    public pixelsToTime(pixels: number): string {
        const minutes = this.pixelsToMinutes(pixels);
        const dayStartMinutes = this.config.get('dayStartHour') * 60;
        const totalMinutes = dayStartMinutes + minutes;
        
        const hours = Math.floor(totalMinutes / 60);
        const mins = Math.round(totalMinutes % 60);
        
        return `${hours.toString().padStart(2, '0')}:${mins.toString().padStart(2, '0')}`;
    }

    /**
     * Beregn event position og størrelse
     */
    public calculateEventPosition(startTime: string | Date, endTime: string | Date): {
        top: number;
        height: number;
        duration: number;
    } {
        let startPixels: number;
        let endPixels: number;

        if (typeof startTime === 'string') {
            startPixels = this.timeToPixels(startTime);
        } else {
            startPixels = this.dateToPixels(startTime);
        }

        if (typeof endTime === 'string') {
            endPixels = this.timeToPixels(endTime);
        } else {
            endPixels = this.dateToPixels(endTime);
        }

        const height = Math.max(endPixels - startPixels, this.getMinimumEventHeight());
        const duration = this.pixelsToMinutes(height);

        return {
            top: startPixels,
            height,
            duration
        };
    }

    /**
     * Snap position til grid interval
     */
    public snapToGrid(pixels: number): number {
        const snapInterval = this.config.get('snapInterval');
        const snapPixels = this.minutesToPixels(snapInterval);
        
        return Math.round(pixels / snapPixels) * snapPixels;
    }

    /**
     * Snap tid til interval
     */
    public snapTimeToInterval(timeString: string): string {
        const [hours, minutes] = timeString.split(':').map(Number);
        const totalMinutes = (hours * 60) + minutes;
        const snapInterval = this.config.get('snapInterval');
        
        const snappedMinutes = Math.round(totalMinutes / snapInterval) * snapInterval;
        const snappedHours = Math.floor(snappedMinutes / 60);
        const remainingMinutes = snappedMinutes % 60;
        
        return `${snappedHours.toString().padStart(2, '0')}:${remainingMinutes.toString().padStart(2, '0')}`;
    }

    /**
     * Beregn kolonne position for overlappende events
     */
    public calculateColumnPosition(eventIndex: number, totalColumns: number, containerWidth: number): {
        left: number;
        width: number;
    } {
        const columnWidth = containerWidth / totalColumns;
        const left = eventIndex * columnWidth;
        
        // Lav lidt margin mellem kolonnerne
        const margin = 2;
        const adjustedWidth = columnWidth - margin;
        
        return {
            left: left + (margin / 2),
            width: Math.max(adjustedWidth, 50) // Minimum width
        };
    }

    /**
     * Check om to events overlapper i tid
     */
    public eventsOverlap(
        start1: string | Date, 
        end1: string | Date, 
        start2: string | Date, 
        end2: string | Date
    ): boolean {
        const pos1 = this.calculateEventPosition(start1, end1);
        const pos2 = this.calculateEventPosition(start2, end2);
        
        const event1End = pos1.top + pos1.height;
        const event2End = pos2.top + pos2.height;
        
        return !(event1End <= pos2.top || event2End <= pos1.top);
    }

    /**
     * Beregn Y position fra mouse/touch koordinat
     */
    public getPositionFromCoordinate(clientY: number, containerElement: HTMLElement): number {
        const rect = containerElement.getBoundingClientRect();
        const relativeY = clientY - rect.top;
        
        // Snap til grid
        return this.snapToGrid(relativeY);
    }

    /**
     * Beregn tid fra mouse/touch koordinat
     */
    public getTimeFromCoordinate(clientY: number, containerElement: HTMLElement): string {
        const position = this.getPositionFromCoordinate(clientY, containerElement);
        return this.pixelsToTime(position);
    }

    /**
     * Valider at tid er inden for arbejdstimer
     */
    public isWithinWorkHours(timeString: string): boolean {
        const [hours] = timeString.split(':').map(Number);
        return hours >= this.config.get('workStartHour') && hours < this.config.get('workEndHour');
    }

    /**
     * Valider at tid er inden for dag grænser
     */
    public isWithinDayBounds(timeString: string): boolean {
        const [hours] = timeString.split(':').map(Number);
        return hours >= this.config.get('dayStartHour') && hours < this.config.get('dayEndHour');
    }

    /**
     * Hent minimum event højde i pixels
     */
    public getMinimumEventHeight(): number {
        // Minimum 15 minutter
        return this.minutesToPixels(15);
    }

    /**
     * Hent maksimum event højde i pixels (hele dagen)
     */
    public getMaximumEventHeight(): number {
        const dayDurationHours = this.config.get('dayEndHour') - this.config.get('dayStartHour');
        return dayDurationHours * this.config.get('hourHeight');
    }

    /**
     * Beregn total kalender højde
     */
    public getTotalCalendarHeight(): number {
        return this.getMaximumEventHeight();
    }

    /**
     * Konverter ISO datetime til lokal tid string
     */
    public isoToTimeString(isoString: string): string {
        const date = new Date(isoString);
        const hours = date.getHours();
        const minutes = date.getMinutes();
        
        return `${hours.toString().padStart(2, '0')}:${minutes.toString().padStart(2, '0')}`;
    }

    /**
     * Konverter lokal tid string til ISO datetime for i dag
     */
    public timeStringToIso(timeString: string, date: Date = new Date()): string {
        const [hours, minutes] = timeString.split(':').map(Number);
        const newDate = new Date(date);
        newDate.setHours(hours, minutes, 0, 0);
        
        return newDate.toISOString();
    }

    /**
     * Beregn event varighed i minutter
     */
    public calculateDuration(startTime: string | Date, endTime: string | Date): number {
        let startMs: number;
        let endMs: number;

        if (typeof startTime === 'string') {
            startMs = new Date(startTime).getTime();
        } else {
            startMs = startTime.getTime();
        }

        if (typeof endTime === 'string') {
            endMs = new Date(endTime).getTime();
        } else {
            endMs = endTime.getTime();
        }

        return Math.round((endMs - startMs) / (1000 * 60)); // Minutter
    }

    /**
     * Format varighed til læsbar tekst
     */
    public formatDuration(minutes: number): string {
        if (minutes < 60) {
            return `${minutes} min`;
        }
        
        const hours = Math.floor(minutes / 60);
        const remainingMinutes = minutes % 60;
        
        if (remainingMinutes === 0) {
            return `${hours} time${hours !== 1 ? 'r' : ''}`;
        }
        
        return `${hours}t ${remainingMinutes}m`;
    }

    /**
     * Opdater konfiguration
     */
    public updateConfig(newConfig: CalendarConfig): void {
        this.config = newConfig;
    }
}