import io
import json
from urllib.parse import urlencode

import chardet
from django.http import JsonResponse
from django.shortcuts import redirect
from django.shortcuts import get_object_or_404, render
from django.views.decorators.http import require_POST

from .services import import_csv_lines
from .models import Expense, ExpenseCategory, Store


def csv_upload(request):
    context = {}
    if request.method == 'POST' and request.FILES.get('csv_file'):
        upload = request.FILES['csv_file']
        raw = upload.read()
        detected = chardet.detect(raw)
        encoding = detected.get('encoding') or 'utf-8'
        text = raw.decode(encoding, errors='ignore')
        lines = io.StringIO(text)
        result = import_csv_lines(lines)
        query = urlencode(
            {'imported': result.imported, 'duplicated': result.duplicated, 'encoding': encoding}
        )
        return redirect(f"/expenses/?{query}")
    return render(request, 'expenses/csv_upload.html', context)


def expense_list(request):
    expenses = Expense.objects.select_related('store', 'expense_category').order_by('-use_date', '-id')[:200]
    stores = Store.objects.filter(is_active=True).order_by('name')
    categories = ExpenseCategory.objects.filter(is_active=True).order_by('name')
    return render(
        request,
        'expenses/expense_list.html',
        {
            'expenses': expenses,
            'stores': stores,
            'categories': categories,
            'imported': request.GET.get('imported'),
            'duplicated': request.GET.get('duplicated'),
            'encoding': request.GET.get('encoding'),
        },
    )


@require_POST
def expense_update(request, expense_id: int):
    try:
        payload = json.loads(request.body.decode('utf-8'))
    except json.JSONDecodeError:
        return JsonResponse({'status': 'error', 'message': 'JSON形式が不正です。'}, status=400)
    if not isinstance(payload, dict):
        return JsonResponse({'status': 'error', 'message': 'JSONはオブジェクトで送信してください。'}, status=400)
    expense = get_object_or_404(Expense, pk=expense_id)
    fields = {}
    for key in ('store_id', 'expense_category_id', 'is_business', 'note'):
        if key in payload:
            value = payload[key]
            if value in ('', None):
                fields[key] = None
            else:
                fields[key] = value
    if 'store_id' in fields and fields['store_id'] is not None:
        if not isinstance(fields['store_id'], int):
            return JsonResponse({'status': 'error', 'message': 'store_idの型が不正です。'}, status=400)
        if not Store.objects.filter(id=fields['store_id'], is_active=True).exists():
            return JsonResponse({'status': 'error', 'message': 'store_idが不正です。'}, status=400)
    if 'expense_category_id' in fields and fields['expense_category_id'] is not None:
        if not isinstance(fields['expense_category_id'], int):
            return JsonResponse({'status': 'error', 'message': 'expense_category_idの型が不正です。'}, status=400)
        if not ExpenseCategory.objects.filter(
            id=fields['expense_category_id'], is_active=True
        ).exists():
            return JsonResponse(
                {'status': 'error', 'message': 'expense_category_idが不正です。'}, status=400
            )
    if 'is_business' in fields and fields['is_business'] is not None:
        if not isinstance(fields['is_business'], bool):
            return JsonResponse({'status': 'error', 'message': 'is_businessの型が不正です。'}, status=400)
    if 'note' in fields and fields['note'] is not None:
        if not isinstance(fields['note'], str):
            return JsonResponse({'status': 'error', 'message': 'noteの型が不正です。'}, status=400)
        if len(fields['note']) > 2000:
            return JsonResponse({'status': 'error', 'message': 'noteが長すぎます。'}, status=400)
    if fields:
        for key, value in fields.items():
            setattr(expense, key, value)
        expense.human_confirmed = True
        expense.save()
    return JsonResponse({'status': 'ok'})


def monthly_report(request):
    return render(request, 'expenses/monthly_report.html')


def monthly_report_pdf(request):
    return render(request, 'expenses/monthly_report_pdf.html')