import csv
import io
from datetime import timedelta

from django.http import HttpResponse
from django.shortcuts import render, redirect, get_object_or_404
from django.contrib.auth.decorators import login_required
from django.utils import timezone

from reportlab.pdfgen import canvas
from reportlab.lib.pagesizes import A4
from reportlab.lib.units import mm

from channels.layers import get_channel_layer
from asgiref.sync import async_to_sync

from .models import Course, Arrivee, Coureur
from .forms import CourseForm, ScanForm, DossardForm

import qrcode
from PIL import Image


def seconds_to_hms(delta: timedelta) -> str:
	if delta is None:
		return ''
	total = int(delta.total_seconds())
	hours = total // 3600
	minutes = (total % 3600) // 60
	seconds = total % 60
	return f"{hours}h{minutes:02d}m{seconds:02d}s"

@login_required
def main_view(request):
	courses = Course.objects.filter(owner=request.user)
	if request.method == 'POST' and request.headers.get('x-requested-with') == 'XMLHttpRequest':
		from django.http import JsonResponse
		nom = request.POST.get('nom')
		date = timezone.localdate()
		if not nom:
			return JsonResponse({'success': False, 'error': "Le nom de la course est requis."})
		if Course.objects.filter(nom=nom, date=date).exists():
			return JsonResponse({'success': False, 'error': "Une course avec ce nom existe d\u00e9j\u00e0 aujourd'hui."})
		course = Course.objects.create(nom=nom, date=date, owner=request.user)
		return JsonResponse({'success': True, 'course_id': course.id})
	form = CourseForm()
	return render(request, 'main.html', {
		'title': 'Accueil',
		'courses': courses,
		'form': form,
		'now': timezone.localdate()
	})

@login_required
def export_csv(request, course_id):
	course = get_object_or_404(Course, id=course_id, owner=request.user)
	response = HttpResponse(content_type='text/csv')
	response['Content-Disposition'] = f'attachment; filename="course_{course_id}_resultats.csv"'
	writer = csv.writer(response)
	writer.writerow(['Rang', 'Nom', 'Classe', 'Temps'])
	import json
	rows_json = request.POST.get('rows')
	if request.method == "POST" and rows_json:
		try:
			rows = json.loads(rows_json)
			for row in rows:
				writer.writerow(row)
		except Exception:
			pass
	else:
		arrivees = course.arrivees.select_related('coureur').order_by('rang')
		for a in arrivees:
			writer.writerow([a.rang, a.coureur.nom, a.coureur.classe, str(a.temps)])
	return response

@login_required
def export_pdf(request, course_id):
	course = get_object_or_404(Course, id=course_id, owner=request.user)
	response = HttpResponse(content_type='application/pdf')
	response['Content-Disposition'] = f'attachment; filename="course_{course_id}_resultats.pdf"'
	p = canvas.Canvas(response, pagesize=A4)
	width, height = A4

	y = height - 50
	p.setFont("Helvetica-Bold", 16)
	p.drawString(50, y, f"R\u00e9sultats - {course.nom} ({course.date})")

	y -= 40
	p.setFont("Helvetica", 12)
	p.drawString(50, y, "Rang")
	p.drawString(100, y, "Nom")
	p.drawString(300, y, "Classe")
	p.drawString(400, y, "Temps")
	y -= 20
	import json
	rows_json = request.POST.get('rows')
	if request.method == "POST" and rows_json:
		try:
			rows = json.loads(rows_json)
			for row in rows:
				p.drawString(50, y, str(row[0]))
				p.drawString(100, y, str(row[1]))
				p.drawString(300, y, str(row[2]))
				p.drawString(400, y, str(row[3]))
				y -= 20
				if y < 50:
					p.showPage()
					y = height - 50
		except Exception:
			pass
	else:
		arrivees = course.arrivees.select_related('coureur').order_by('rang')
		for a in arrivees:
			p.drawString(50, y, str(a.rang))
			p.drawString(100, y, a.coureur.nom)
			p.drawString(300, y, a.coureur.classe)
			p.drawString(400, y, str(a.temps))
			y -= 20
			if y < 50:
				p.showPage()
				y = height - 50
	p.save()
	return response

@login_required
def course_detail_view(request, course_id):
	course = get_object_or_404(Course, id=course_id, owner=request.user)
	arrivees = course.arrivees.select_related('coureur').order_by('rang')
	is_started = course.depart is not None
	is_finished = course.fin is not None

	if request.method == 'POST':
		if 'start' in request.POST and not is_started:
			course.depart = timezone.now()
			course.save()
			is_started = True
		elif 'finish' in request.POST and is_started and not is_finished:
			course.fin = timezone.now()
			course.save()
			is_finished = True
		return redirect('course_detail', course_id=course.id)

	return render(request, 'course_detail.html', {
		'title': 'Course : '+course.nom+" ("+str(course.date)+")",
		'course': course,
		'arrivees': arrivees,
		'is_started': is_started,
		'is_finished': is_finished
	})

@login_required
def scan_view(request):
	courses = Course.objects.filter(owner=request.user, depart__isnull=False, fin__isnull=True)
	result = None
	error = None
	course = None

	if request.method == 'POST' and request.headers.get('x-requested-with') == 'XMLHttpRequest':
		course_id = request.POST.get('course_id')
		qrcode = request.POST.get('qrcode')
		if not course_id or not qrcode:
			error = "Param\u00e8tres manquants."
		else:
			# ensure user can only scan their own course
			course = get_object_or_404(Course, id=course_id, owner=request.user)

			# QR code now contains the unique Coureur id
			coureur = None
			try:
				coureur = Coureur.objects.get(id=qrcode.strip())
			except Coureur.DoesNotExist:
				error = "Coureur introuvable pour ce code QR."

			if coureur:
				if Arrivee.objects.filter(course=course, coureur=coureur).exists():
					error = "Ce coureur a d\u00e9j\u00e0 \u00e9t\u00e9 scann\u00e9."
				else:
					temps = timezone.now() - course.depart
					rang = Arrivee.objects.filter(course=course).count() + 1
					Arrivee.objects.create(course=course, coureur=coureur, temps=temps, rang=rang)
					result = {
						'nom': coureur.nom,
						'prenom': coureur.prenom,
						'classe': coureur.classe,
						'rang': rang,
						'temps': str(seconds_to_hms(temps))
					}
					channel_layer = get_channel_layer()
					async_to_sync(channel_layer.group_send)(
						f'course_{course.id}',
						{
							'type': 'send_arrivee',
							'data': result
						}
					)

		if result:
			return render(request, 'scan_result.html', {'result': result})
		else:
			return render(request, 'scan_result.html', {'error': error})

	else:
		course_id = request.GET.get('course_id')
		if course_id:
			course = get_object_or_404(Course, id=course_id, owner=request.user)

		return render(request, 'scan.html', {
			'title': 'Scan course : '+(course.nom+" ("+str(course.date)+")" if course else ''),
			'courses': courses,
			'result': result,
			'error': error,
			'course': course
		})

@login_required
def dossards_view(request):
	error = None
	progress = None
	pdf_url = None
	if request.method == 'POST':
		# Get the list of Coureur IDs from the POST data
		coureur_ids_str = request.POST.get('coureur_ids', '')
		rows = int(request.POST.get('rows', 2))
		cols = int(request.POST.get('cols', 2))
		try:
			coureur_ids = [cid for cid in coureur_ids_str.split(',') if cid.strip()]
			if not coureur_ids:
				error = "Aucun coureur sélectionné."
			else:
				# Accept both PKs and names for fallback (legacy/fallback)
				coureurs = list(Coureur.objects.filter(id__in=coureur_ids))
				# If fallback: try by name if not found by id
				if len(coureurs) < len(coureur_ids):
					missing = set(coureur_ids) - set(str(c.id) for c in coureurs)
					for nom in missing:
						c = Coureur.objects.filter(nom=nom).first()
						if c:
							coureurs.append(c)
				if not coureurs:
					error = "Aucun coureur trouvé pour les IDs fournis."
				else:
					buffer = generate_dossards_pdf(coureurs, rows, cols)
					response = HttpResponse(buffer, content_type='application/pdf')
					response['Content-Disposition'] = f'attachment; filename="dossards_{rows}x{cols}.pdf"'
					return response
		except Exception as e:
			error = str(e)
	# Liste des coureurs et des classes distinctes pour la DataTable
	coureurs = Coureur.objects.all().order_by('nom', 'prenom', 'classe')
	classes = Coureur.objects.values_list('classe', flat=True).distinct().order_by('classe')
	return render(request, 'dossards.html', {
		'title': 'G\u00e9n\u00e9ration des dossards PDF',
		'error': error,
		'progress': progress,
		'pdf_url': pdf_url,
		'coureurs': coureurs,
		'classes': classes,
	})


def generate_dossards_pdf(data, rows, cols):
	import io
	from reportlab.pdfgen import canvas
	from reportlab.lib.pagesizes import A4
	buffer = io.BytesIO()
	c = canvas.Canvas(buffer, pagesize=A4)
	width, height = A4
	margin = 10 * mm
	label_w = (width - 2 * margin) / cols
	label_h = (height - 2 * margin) / rows
	x0, y0 = margin, height - margin - label_h
	qr_scale = 0.8  # 80% of the label area for the QR
	for idx, coureur in enumerate(data):
		col = idx % cols
		row = (idx // cols) % rows
		page = idx // (rows * cols)
		if idx > 0 and row == 0 and col == 0:
			c.showPage()
		x = x0 + col * label_w
		y = y0 - row * label_h
		c.setLineWidth(3)
		c.setStrokeColorRGB(0, 0, 0)
		c.rect(x, y, label_w, label_h)
		# Generate QR
		# QR contains the unique coureur id
		qr = qrcode.make(f"{coureur.id}")
		qr_img = io.BytesIO()
		qr.save(qr_img, format='PNG')
		qr_img.seek(0)
		qr_pil = Image.open(qr_img)
		qr_size = min(label_w, label_h) * qr_scale
		qr_x = x + (label_w - qr_size) / 2
		qr_y = y + (label_h - qr_size) / 2
		c.drawInlineImage(qr_pil, qr_x, qr_y, qr_size, qr_size)
		c.setFont("Helvetica-Bold", 12)
		# Display nom, prenom, classe
		full_name = f"{coureur.nom} {coureur.prenom}".strip()
		c.drawCentredString(x + label_w/2, qr_y - 10, full_name)
		c.setFont("Helvetica", 10)
		c.drawCentredString(x + label_w/2, qr_y - 24, coureur.classe)
	c.save()
	buffer.seek(0)
	return buffer