"""Copy saved Ocado product photos into Grocy's native product pictures."""
import base64
import hashlib
import json
from pathlib import Path
import tomllib
from urllib.parse import quote, urlsplit

import click
import requests

from .grocy import Grocy, imported_products
from .paths import config_file, archive_directory, journal_file
from .history import private_json
from .product_metadata import read_metadata


def image_type(data):
    if data.startswith(b'\xff\xd8\xff'):
        return 'jpg'
    if data.startswith(b'\x89PNG\r\n\x1a\n'):
        return 'png'
    if data.startswith(b'RIFF') and data[8:12] == b'WEBP':
        return 'webp'
    raise ValueError('Image response is not JPEG, PNG or WebP')


def file_path(filename):
    return '/files/productpictures/' + quote(base64.b64encode(filename.encode()).decode(), safe='')


def add_picture(client, downloader, product):
    if product.get('picture_file_name'):
        return 'existing_picture'
    metadata = read_metadata(product.get('description'))
    url = metadata.get('image_url')
    if not url:
        return 'no_image_url'
    parsed = urlsplit(url)
    if parsed.scheme != 'https' or parsed.hostname not in {'www.ocado.com', 'ocado.com'}:
        raise ValueError('Expected an HTTPS Ocado image URL')
    # Separate session: never send the Grocy API key to the image host.
    response = downloader.get(url, timeout=30, allow_redirects=False)
    response.raise_for_status()
    if response.status_code != 200:
        raise ValueError('Image URL did not return HTTP 200')
    data = response.content
    extension = image_type(data)
    if len(data) > 10_000_000:
        raise ValueError('Image exceeds 10 MB')
    filename = f"ocado-{int(product['id'])}-{hashlib.sha256(data).hexdigest()[:16]}.{extension}"
    current = client.get(f"/objects/products/{product['id']}")
    if not current:
        return 'deleted_product'
    if current.get('picture_file_name'):
        return 'existing_picture'
    if read_metadata(current.get('description')).get('Ocado product ID') != metadata.get('Ocado product ID'):
        raise ValueError('Product identity changed')
    path = file_path(filename)
    uploaded = client.session.put(client.url + path, data=data,
                                  headers={'Content-Type':'application/octet-stream'},
                                  timeout=client.timeout, allow_redirects=False)
    uploaded.raise_for_status()
    if uploaded.status_code not in (200, 201, 204):
        raise ValueError('Unexpected upload response')
    # Check the stored file before setting the product's picture reference.
    stored = client.session.get(client.url + path, timeout=client.timeout, allow_redirects=False)
    stored.raise_for_status()
    if stored.status_code != 200 or stored.content != data:
        raise ValueError('Uploaded image verification failed')
    client.request('PUT', f"/objects/products/{product['id']}", {'picture_file_name':filename})
    return 'updated'


@click.command()
@click.option('--config', type=click.Path(path_type=Path), default=config_file, show_default='~/.config/ocado-grocy/config.toml')
@click.option('--report', type=click.Path(path_type=Path), default=lambda: archive_directory() / 'images/report.json', show_default='archive/images/report.json')
@click.option('--apply', is_flag=True, help='Upload and assign missing product pictures.')
@click.option('--order-id', 'order_ids', multiple=True, help='Limit to products imported from these orders.')
def main(config, report, apply, order_ids):
    """Add Ocado images to journal-linked products; keep existing pictures."""
    settings = tomllib.loads(config.read_text())
    client = Grocy(**settings['grocy'])
    state = journal_file(settings, config)
    products = imported_products(client, state, order_ids)
    return run_images(client, products, report, apply=apply)


def run_images(client, products, report, *, apply=True, raise_errors=True):
    downloader = requests.Session()
    downloader.headers['User-Agent'] = 'ocado-grocy/0.1'
    results = []
    private_json(report, {'apply':apply, 'products':results})
    for product in products:
        row = {'product_id':product['id'], 'name':product['name']}
        try:
            if apply:
                row['status'] = add_picture(client, downloader, product)
            else:
                row['status'] = 'existing_picture' if product.get('picture_file_name') else 'ready' if read_metadata(product.get('description')).get('image_url') else 'no_image_url'
        except (requests.RequestException, ValueError) as exc:
            row.update(status='error', error=str(exc))
        results.append(row)
        private_json(report, {'apply':apply, 'products':results})
        click.echo(f"{product['id']} {row['status']}: {product['name']}")
    counts = {s:sum(r['status']==s for r in results) for s in sorted({r['status'] for r in results})}
    click.echo(json.dumps(counts))
    if counts.get('error') and raise_errors:
        raise click.ClickException(f"{counts['error']} image updates failed; see {report}")
    return {'products':results, 'counts':counts}


if __name__ == '__main__':
    main()