# -*- coding: utf-8 -*-
import base64
import io
import json
import os
from datetime import datetime

from dateutil import parser
from flask import (
    Response,
    flash,
    jsonify,
    redirect,
    render_template,
    request,
    send_file,
    stream_with_context,
    url_for,
)
from notifications_python_client.errors import APIError
from notifications_utils.letter_timings import (
    get_letter_timings,
    letter_can_be_cancelled,
)
from notifications_utils.pdf import pdf_page_count
from PyPDF2.utils import PdfReadError

from app import (
    current_service,
    format_date_numeric,
    job_api_client,
    notification_api_client,
)
from app.main import main
from app.notify_client.api_key_api_client import KEY_TYPE_TEST
from app.template_previews import get_page_count_for_letter
from app.utils import (
    DELIVERED_STATUSES,
    FAILURE_STATUSES,
    generate_notifications_csv,
    get_help_argument,
    get_letter_printing_statement,
    get_letter_validation_error,
    get_template,
    parse_filter_args,
    set_status_filters,
    user_has_permissions,
)


@main.route("/services/<uuid:service_id>/notification/<uuid:notification_id>")
@user_has_permissions('view_activity', 'send_messages')
def view_notification(service_id, notification_id):
    notification = notification_api_client.get_notification(service_id, str(notification_id))
    notification['template'].update({'reply_to_text': notification['reply_to_text']})

    personalisation = get_all_personalisation_from_notification(notification)
    error_message = None
    if notification['template']['is_precompiled_letter']:
        try:
            file_contents, metadata = get_letter_file_data(
                service_id, notification_id, "pdf", with_metadata=True
            )
            page_count = int(
                metadata["page_count"]
            ) if metadata.get("page_count") else pdf_page_count(io.BytesIO(file_contents))
            if notification["status"] == "validation-failed":
                invalid_pages = metadata.get("invalid_pages")
                invalid_pages = json.loads(invalid_pages) if invalid_pages else invalid_pages
                error_message = get_letter_validation_error(
                    metadata.get("message"), invalid_pages, page_count
                )
        except PdfReadError:
            return render_template(
                'views/notifications/invalid_precompiled_letter.html',
                created_at=notification['created_at']
            )
    else:
        page_count = get_page_count_for_letter(notification['template'], values=personalisation)

    if notification.get('postage'):
        if notification["status"] == "validation-failed":
            notification['template']['postage'] = None
        else:
            notification['template']['postage'] = notification['postage']
    template = get_template(
        notification['template'],
        current_service,
        letter_preview_url=url_for(
            '.view_letter_notification_as_preview',
            service_id=service_id,
            notification_id=notification_id,
            filetype='png',
        ),
        page_count=page_count,
        show_recipient=True,
        redact_missing_personalisation=True,
    )
    template.values = personalisation
    if notification['job']:
        job = job_api_client.get_job(service_id, notification['job']['id'])['data']
    else:
        job = None

    letter_print_day = get_letter_printing_statement(notification['status'], notification['created_at'])

    notification_created = parser.parse(notification['created_at']).replace(tzinfo=None)

    show_cancel_button = notification['notification_type'] == 'letter' and \
        letter_can_be_cancelled(notification['status'], notification_created)

    if get_help_argument() or request.args.get('help') == '0':
        # help=0 is set when you’ve just sent a notification. We
        # only want to show the back link when you’ve navigated to a
        # notification, not when you’ve just sent it.
        back_link = None
    elif request.args.get('from_job'):
        back_link = url_for(
            'main.view_job',
            service_id=current_service.id,
            job_id=request.args.get('from_job'),
        )
    elif request.args.get('from_uploaded_letters'):
        back_link = url_for(
            'main.uploaded_letters',
            service_id=current_service.id,
            letter_print_day=request.args.get('from_uploaded_letters'),
        )
    else:
        back_link = url_for(
            'main.view_notifications',
            service_id=current_service.id,
            message_type=template.template_type,
            status='sending,delivered,failed',
        )

    if notification['notification_type'] == 'letter':
        estimated_letter_delivery_date = get_letter_timings(
            notification['created_at'],
            postage=notification['postage']
        ).earliest_delivery
    else:
        estimated_letter_delivery_date = None

    return render_template(
        'views/notifications/notification.html',
        finished=(notification['status'] in (DELIVERED_STATUSES + FAILURE_STATUSES)),
        notification_status=notification['status'],
        message=error_message,
        uploaded_file_name='Report',
        template=template,
        job=job,
        updates_url=url_for(
            ".view_notification_updates",
            service_id=service_id,
            notification_id=notification['id'],
            status=request.args.get('status'),
            help=get_help_argument()
        ),
        partials=get_single_notification_partials(notification),
        created_by=notification.get('created_by'),
        created_at=notification['created_at'],
        updated_at=notification['updated_at'],
        help=get_help_argument(),
        estimated_letter_delivery_date=estimated_letter_delivery_date,
        notification_id=notification['id'],
        postage=notification['postage'],
        can_receive_inbound=(current_service.has_permission('inbound_sms')),
        is_precompiled_letter=notification['template']['is_precompiled_letter'],
        letter_print_day=letter_print_day,
        show_cancel_button=show_cancel_button,
        sent_with_test_key=(
            notification.get('key_type') == KEY_TYPE_TEST
        ),
        back_link=back_link,
    )


@main.route("/services/<uuid:service_id>/notification/<uuid:notification_id>/cancel", methods=['GET', 'POST'])
@user_has_permissions('view_activity', 'send_messages')
def cancel_letter(service_id, notification_id):

    if request.method == 'POST':
        notification_api_client.update_notification_to_cancelled(current_service.id, notification_id)
        return redirect(url_for('main.view_notification', service_id=service_id, notification_id=notification_id))

    flash("Are you sure you want to cancel sending this letter?", 'cancel')
    return view_notification(service_id, notification_id)


def get_preview_error_image():
    path = os.path.join(os.path.dirname(__file__), "..", "..", "static", "images", "preview_error.png")
    with open(path, "rb") as file:
        return file.read()


@main.route("/services/<uuid:service_id>/notification/<uuid:notification_id>.<letter_file_extension:filetype>")
@user_has_permissions('view_activity')
def view_letter_notification_as_preview(
    service_id, notification_id, filetype, with_metadata=False
):
    image_data = get_letter_file_data(service_id, notification_id, filetype, with_metadata)
    file = io.BytesIO(image_data)

    mimetype = 'image/png' if filetype == 'png' else 'application/pdf'

    return send_file(
        filename_or_fp=file,
        mimetype=mimetype,
    )


def get_letter_file_data(service_id, notification_id, filetype, with_metadata=False):
    try:
        preview = notification_api_client.get_notification_letter_preview(
            service_id,
            notification_id,
            filetype,
            page=request.args.get('page')
        )

        display_file = base64.b64decode(preview['content'])
    except APIError:
        display_file = get_preview_error_image()
        preview = {"metadata": {}}

    if with_metadata:
        return display_file, preview['metadata']
    return display_file


@main.route("/services/<uuid:service_id>/notification/<uuid:notification_id>.json")
@user_has_permissions('view_activity', 'send_messages')
def view_notification_updates(service_id, notification_id):
    return jsonify(**get_single_notification_partials(
        notification_api_client.get_notification(service_id, notification_id)
    ))


def get_single_notification_partials(notification):
    return {
        'status': render_template(
            'partials/notifications/status.html',
            notification=notification,
            sent_with_test_key=(
                notification.get('key_type') == KEY_TYPE_TEST
            ),
        ),
    }


def get_all_personalisation_from_notification(notification):

    if notification['template'].get('redact_personalisation'):
        notification['personalisation'] = {}

    if notification['template']['template_type'] == 'email':
        notification['personalisation']['email_address'] = notification['to']

    if notification['template']['template_type'] == 'sms':
        notification['personalisation']['phone_number'] = notification['to']

    return notification['personalisation']


@main.route("/services/<uuid:service_id>/download-notifications.csv")
@user_has_permissions('view_activity')
def download_notifications_csv(service_id):
    filter_args = parse_filter_args(request.args)
    filter_args['status'] = set_status_filters(filter_args)

    service_data_retention_days = current_service.get_days_of_retention(filter_args.get('message_type')[0])
    return Response(
        stream_with_context(
            generate_notifications_csv(
                service_id=service_id,
                job_id=None,
                status=filter_args.get('status'),
                page=request.args.get('page', 1),
                page_size=10000,
                format_for_csv=True,
                template_type=filter_args.get('message_type'),
                limit_days=service_data_retention_days,
            )
        ),
        mimetype='text/csv',
        headers={
            'Content-Disposition': 'inline; filename="{} - {} - {} report.csv"'.format(
                format_date_numeric(datetime.now().strftime("%Y-%m-%dT%H:%M:%S.%fZ")),
                filter_args['message_type'][0],
                current_service.name)
        }
    )