import io
import json
from datetime import date, datetime, timedelta
from urllib.parse import urlencode

import chardet
from django.db import IntegrityError
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 build_monthly_report, 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)
        try:
            result = import_csv_lines(lines)
        except ValueError as exc:
            context['error_message'] = str(exc)
            return render(request, 'expenses/csv_upload.html', context)
        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):
    include_canceled = request.GET.get('include_canceled') == '1'
    queryset = Expense.objects.select_related('store', 'expense_category')
    if not include_canceled:
        queryset = queryset.filter(is_canceled=False)
    expenses = queryset.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'),
            'include_canceled': include_canceled,
        },
    )


def store_master(request):
    error_message = None
    if request.method == 'POST':
        name = request.POST.get('name', '').strip()
        store_id = request.POST.get('store_id')
        action = request.POST.get('action')
        if action == 'deactivate' and store_id:
            store = get_object_or_404(Store, pk=store_id)
            store.is_active = False
            store.save(update_fields=['is_active'])
        else:
            is_active = request.POST.get('is_active') == '1'
            if not name:
                error_message = '店舗名を入力してください。'
            else:
                try:
                    if store_id:
                        store = get_object_or_404(Store, pk=store_id)
                        store.name = name
                        store.is_active = is_active
                        store.save(update_fields=['name', 'is_active'])
                    else:
                        Store.objects.create(name=name, is_active=is_active)
                except IntegrityError:
                    error_message = '同名の店舗が既に存在します。'
    stores = Store.objects.order_by('name', 'id')
    return render(
        request,
        'expenses/store_master.html',
        {
            'stores': stores,
            'error_message': error_message,
        },
    )


def expense_category_master(request):
    error_message = None
    if request.method == 'POST':
        name = request.POST.get('name', '').strip()
        category_id = request.POST.get('category_id')
        action = request.POST.get('action')
        if action == 'deactivate' and category_id:
            category = get_object_or_404(ExpenseCategory, pk=category_id)
            category.is_active = False
            category.save(update_fields=['is_active'])
        else:
            is_active = request.POST.get('is_active') == '1'
            if not name:
                error_message = '経費区分名を入力してください。'
            else:
                try:
                    if category_id:
                        category = get_object_or_404(ExpenseCategory, pk=category_id)
                        category.name = name
                        category.is_active = is_active
                        category.save(update_fields=['name', 'is_active'])
                    else:
                        ExpenseCategory.objects.create(name=name, is_active=is_active)
                except IntegrityError:
                    error_message = '同名の経費区分が既に存在します。'
    categories = ExpenseCategory.objects.order_by('name', 'id')
    return render(
        request,
        'expenses/expense_category_master.html',
        {
            'categories': categories,
            'error_message': error_message,
        },
    )


@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', 'owner_type', 'note'):
        if key in payload:
            value = payload[key]
            if value in ('', None):
                if key == 'owner_type':
                    fields[key] = 'pending'
                else:
                    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 'owner_type' in fields and fields['owner_type'] is not None:
        if not isinstance(fields['owner_type'], str):
            return JsonResponse({'status': 'error', 'message': 'owner_typeの型が不正です。'}, status=400)
        if fields['owner_type'] not in {'company', 'personal', 'pending'}:
            return JsonResponse({'status': 'error', 'message': 'owner_type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):
    error_message = None
    start_date_param = request.GET.get('start_date', '')
    end_date_param = request.GET.get('end_date', '')
    all_time = request.GET.get('all_time') == '1'
    store_param = request.GET.get('store_id', '')
    category_param = request.GET.get('expense_category_id', '')
    description_query = request.GET.get('description', '').strip()
    show_report = request.GET.get('show') == '1'
    store_id = None
    store_is_null = False
    expense_category_id = None
    expense_category_is_null = False
    if store_param == 'unassigned':
        store_is_null = True
    elif store_param:
        try:
            store_id = int(store_param)
        except ValueError:
            error_message = '店舗区分の指定が不正です。'
    if category_param == 'unassigned':
        expense_category_is_null = True
    elif category_param:
        try:
            expense_category_id = int(category_param)
        except ValueError:
            error_message = '経費区分の指定が不正です。'
    if start_date_param or end_date_param:
        all_time = False
    if all_time:
        start_date = None
        end_date = None
        end_date_display = ''
    else:
        start_date = None
        end_date = None
        end_date_display = end_date_param
        if start_date_param:
            try:
                start_date = datetime.strptime(start_date_param, '%Y-%m-%d').date()
            except ValueError:
                error_message = '開始日の形式が不正です。'
        if end_date_param:
            try:
                end_date = datetime.strptime(end_date_param, '%Y-%m-%d').date()
            except ValueError:
                error_message = '終了日の形式が不正です。'
        if start_date is None and end_date is None and error_message is None:
            start_date = date.today().replace(day=1)
            if start_date.month == 12:
                next_month = start_date.replace(year=start_date.year + 1, month=1)
            else:
                next_month = start_date.replace(month=start_date.month + 1)
            end_date = next_month - timedelta(days=1)
            start_date_param = start_date.strftime('%Y-%m-%d')
            end_date_display = end_date.strftime('%Y-%m-%d')
        if end_date is not None:
            end_date = end_date + timedelta(days=1)
    stores = Store.objects.filter(is_active=True).order_by('name')
    categories = ExpenseCategory.objects.filter(is_active=True).order_by('name')
    report = None
    if show_report and error_message is None:
        report = build_monthly_report(
            start_date,
            end_date,
            store_id=store_id,
            store_is_null=store_is_null,
            expense_category_id=expense_category_id,
            expense_category_is_null=expense_category_is_null,
            description_query=description_query or None,
        )
    return render(
        request,
        'expenses/monthly_report.html',
        {
            'report': report,
            'start_date': start_date_param or (start_date.strftime('%Y-%m-%d') if start_date else ''),
            'end_date': end_date_display,
            'all_time': all_time,
            'stores': stores,
            'selected_store': store_param,
            'categories': categories,
            'selected_category': category_param,
            'description_query': description_query,
            'show_report': show_report,
            'error_message': error_message,
        },
    )


def monthly_report_pdf(request):
    start_date_param = request.GET.get('start_date', '')
    end_date_param = request.GET.get('end_date', '')
    all_time = request.GET.get('all_time') == '1'
    store_param = request.GET.get('store_id', '')
    category_param = request.GET.get('expense_category_id', '')
    description_query = request.GET.get('description', '').strip()
    store_id = None
    store_is_null = False
    expense_category_id = None
    expense_category_is_null = False
    if store_param == 'unassigned':
        store_is_null = True
    elif store_param:
        try:
            store_id = int(store_param)
        except ValueError:
            store_id = None
    if category_param == 'unassigned':
        expense_category_is_null = True
    elif category_param:
        try:
            expense_category_id = int(category_param)
        except ValueError:
            expense_category_id = None
    if start_date_param or end_date_param:
        all_time = False
    if all_time:
        start_date = None
        end_date = None
        target_period = '全期間'
    else:
        start_date = None
        end_date = None
        if start_date_param:
            try:
                start_date = datetime.strptime(start_date_param, '%Y-%m-%d').date()
            except ValueError:
                start_date = None
        if end_date_param:
            try:
                end_date = datetime.strptime(end_date_param, '%Y-%m-%d').date()
            except ValueError:
                end_date = None
        if start_date is None and end_date is None:
            start_date = date.today().replace(day=1)
            if start_date.month == 12:
                next_month = start_date.replace(year=start_date.year + 1, month=1)
            else:
                next_month = start_date.replace(month=start_date.month + 1)
            end_date = next_month - timedelta(days=1)
        start_label = start_date.strftime('%Y-%m-%d') if start_date else '未指定'
        end_label = end_date.strftime('%Y-%m-%d') if end_date else '未指定'
        target_period = f'{start_label} 〜 {end_label}'
        if end_date is not None:
            end_date = end_date + timedelta(days=1)
    report = build_monthly_report(
        start_date,
        end_date,
        store_id=store_id,
        store_is_null=store_is_null,
        expense_category_id=expense_category_id,
        expense_category_is_null=expense_category_is_null,
        description_query=description_query or None,
    )
    return render(
        request,
        'expenses/monthly_report_pdf.html',
        {
            'report': report,
            'target_period': target_period,
        },
    )


@require_POST
def expense_cancel(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)
    if 'is_canceled' not in payload:
        return JsonResponse({'status': 'error', 'message': 'is_canceledが必要です。'}, status=400)
    if not isinstance(payload['is_canceled'], bool):
        return JsonResponse({'status': 'error', 'message': 'is_canceledの型が不正です。'}, status=400)
    expense = get_object_or_404(Expense, pk=expense_id)
    expense.is_canceled = payload['is_canceled']
    expense.human_confirmed = True
    expense.save(update_fields=['is_canceled', 'human_confirmed', 'updated_at'])
    return JsonResponse({'status': 'ok'})