flickr-mail/main.py

#!/usr/bin/python3
"""Find photos on flickr for Wikipedia articles and contact the photographer."""

import collections
import dataclasses
import inspect
import json
import sys
import time
import traceback
import typing
from urllib.parse import quote, unquote

import flask
import requests
import werkzeug
from sqlalchemy import func
from werkzeug.debug.tbtools import DebugTraceback

from flickr_mail.database import get_session
from flickr_mail.models import FlickrUpload, InteractionLog, SentMessage, ThumbnailCache
from flickr_mail.url_utils import extract_urls_from_message, normalize_flickr_url

import re


app = flask.Flask(__name__)
app.debug = False

enwiki = "en.wikipedia.org/wiki/"

COMMONS_CACHE_MAX_AGE = 86400 * 7  # Cache for 7 days
RECENT_UPLOADS_COUNT = 24

# User agent for Wikimedia API requests
WIKIMEDIA_USER_AGENT = (
    "FlickrMail/1.0 (https://edwardbetts.com/flickr_mail/; edward@4angle.com)"
)

WIKIPEDIA_API = "https://en.wikipedia.org/w/api.php"

# Browser-like headers for Flickr requests
BROWSER_HEADERS = {
    "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36",
    "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8",
    "Accept-Language": "en-US,en;q=0.9",
    "Accept-Encoding": "gzip, deflate, br",
    "Connection": "keep-alive",
    "Upgrade-Insecure-Requests": "1",
    "Sec-Fetch-Dest": "document",
    "Sec-Fetch-Mode": "navigate",
    "Sec-Fetch-Site": "none",
    "Sec-Fetch-User": "?1",
    "Cache-Control": "max-age=0",
}


# Flickr license codes to human-readable names
FLICKR_LICENSES = {
    0: "All Rights Reserved",
    1: "CC BY-NC-SA 2.0",
    2: "CC BY-NC 2.0",
    3: "CC BY-NC-ND 2.0",
    4: "CC BY 2.0",
    5: "CC BY-SA 2.0",
    6: "CC BY-ND 2.0",
    7: "No known copyright",
    8: "US Government",
    9: "CC0",
    10: "Public Domain",
    # CC 4.0 licenses (codes confirmed via Flickr)
    16: "CC BY-NC-ND 4.0",
}

# Non-free CC licenses (NC or ND restrictions)
NONFREE_CC_LICENSES = {1, 2, 3, 6, 11, 12, 13, 16}

# Wikipedia-compatible free licenses
FREE_LICENSES = {4, 5, 7, 8, 9, 10, 14, 15}


PHOTOS_PER_PAGE = 25


@dataclasses.dataclass
class FlickrPhoto:
    """Represents a Flickr photo from search results."""

    id: str
    title: str
    path_alias: str
    owner_nsid: str
    username: str
    realname: str
    license: int
    thumb_url: str
    medium_url: str

    @property
    def flickr_url(self) -> str:
        """URL to the photo page on Flickr."""
        return f"https://flickr.com/photos/{self.path_alias}/{self.id}"

    @property
    def license_name(self) -> str:
        """Human-readable license name."""
        return FLICKR_LICENSES.get(self.license, f"License {self.license}")


@dataclasses.dataclass
class SearchResult:
    """Flickr search results with pagination metadata."""

    photos: list[FlickrPhoto]
    total_photos: int
    current_page: int
    total_pages: int


@dataclasses.dataclass
class CommonsUpload:
    """Represents a recent upload to Wikimedia Commons."""

    title: str
    thumb_url: str
    commons_url: str
    flickr_url: str
    creator: str
    timestamp: str
    wikipedia_url: str = ""
    creator_profile_url: str = ""

    @property
    def is_wikidata_item(self) -> bool:
        """Check if the wikipedia_url is actually a Wikidata item."""
        if not self.wikipedia_url:
            return False
        # Match Q followed by digits at the end of the URL
        return bool(re.search(r"/Q\d+$", self.wikipedia_url))

    @property
    def wiki_link_url(self) -> str:
        """Get the correct URL (Wikidata if it's a Q item, otherwise Wikipedia)."""
        if not self.wikipedia_url:
            return ""
        if self.is_wikidata_item:
            # Extract Q-id and build Wikidata URL
            match = re.search(r"(Q\d+)$", self.wikipedia_url)
            if match:
                return f"https://www.wikidata.org/wiki/{match.group(1)}"
        return self.wikipedia_url

    @property
    def wiki_link_label(self) -> str:
        """Get the label for the wiki link."""
        return "Wikidata item" if self.is_wikidata_item else "Wikipedia article"



def fetch_commons_thumbnails(titles: list[str]) -> dict[str, str]:
    """Fetch thumbnail URLs from Commons API for the given file titles."""
    if not titles:
        return {}

    # Commons API allows up to 50 titles per request
    params = {
        "action": "query",
        "titles": "|".join(titles),
        "prop": "imageinfo",
        "iiprop": "url",
        "iiurlwidth": 150,
        "format": "json",
    }

    headers = {"User-Agent": WIKIMEDIA_USER_AGENT}

    try:
        response = requests.get(
            "https://commons.wikimedia.org/w/api.php",
            params=params,
            headers=headers,
            timeout=10,
        )
        response.raise_for_status()
        data = response.json()
    except (requests.RequestException, json.JSONDecodeError):
        return {}

    thumbnails: dict[str, str] = {}
    pages = data.get("query", {}).get("pages", {})
    for page in pages.values():
        title = page.get("title", "")
        imageinfo = page.get("imageinfo", [])
        if imageinfo:
            thumb_url = imageinfo[0].get("thumburl", "")
            if thumb_url:
                thumbnails[title] = thumb_url

    return thumbnails


def get_recent_commons_uploads() -> tuple[list[CommonsUpload], int]:
    """Get recent Commons uploads with thumbnails, filtered to those contacted via Flickr mail.

    Returns a tuple of (uploads_list, total_count) where total_count is the total number
    of uploads obtained via Flickr mail (not just the ones returned).
    """
    session = get_session()
    try:
        query = (
            session.query(FlickrUpload, SentMessage)
            .join(SentMessage)
            .order_by(FlickrUpload.timestamp.desc())
        )
        total_matched = query.count()
        if total_matched == 0:
            return [], 0

        recent = query.limit(RECENT_UPLOADS_COUNT).all()

        # Get thumbnails from cache
        titles = [upload.title for upload, msg in recent]
        now = int(time.time())
        cached = {
            tc.title: tc
            for tc in session.query(ThumbnailCache)
            .filter(ThumbnailCache.title.in_(titles))
            .all()
        }

        # Find titles needing fetch (missing or expired)
        titles_to_fetch = [
            t for t in titles
            if t not in cached or (now - (cached[t].fetched_at or 0)) > COMMONS_CACHE_MAX_AGE
        ]

        if titles_to_fetch:
            new_thumbs = fetch_commons_thumbnails(titles_to_fetch)
            for title, thumb_url in new_thumbs.items():
                existing = cached.get(title)
                if existing:
                    existing.thumb_url = thumb_url
                    existing.fetched_at = now
                else:
                    tc = ThumbnailCache(title=title, thumb_url=thumb_url, fetched_at=now)
                    session.add(tc)
                    cached[title] = tc
            session.commit()

        result: list[CommonsUpload] = []
        for upload, msg in recent:
            thumb_url = cached[upload.title].thumb_url if upload.title in cached else ""
            if not thumb_url:
                continue

            commons_url = f"https://commons.wikimedia.org/wiki/{upload.title.replace(' ', '_')}"

            result.append(
                CommonsUpload(
                    title=upload.title.replace("File:", "").rsplit(".", 1)[0],
                    thumb_url=thumb_url,
                    commons_url=commons_url,
                    flickr_url=upload.flickr_url or "",
                    creator=upload.creator or "Unknown",
                    timestamp=(upload.timestamp or "")[:10],
                    wikipedia_url=upload.wikipedia_url or "",
                    creator_profile_url=upload.creator_profile_url or "",
                )
            )

        return result, total_matched
    finally:
        session.close()


def get_previous_messages(flickr_user: str, flickr_username: str) -> list[dict]:
    """Get previous messages sent to a Flickr user.

    Checks both the display name (flickr_user) and username (flickr_username)
    against the recipient field in the messages index.
    """
    names = set()
    if flickr_user:
        names.add(flickr_user.lower())
    if flickr_username:
        names.add(flickr_username.lower())
    if not names:
        return []

    session = get_session()
    try:
        messages = (
            session.query(SentMessage)
            .filter(func.lower(SentMessage.recipient).in_(names))
            .all()
        )
        return [
            {
                "message_id": m.message_id,
                "subject": m.subject,
                "url": m.url,
                "recipient": m.recipient,
                "date": m.date,
            }
            for m in messages
        ]
    finally:
        session.close()


def parse_category_input(category_input: str) -> str | None:
    """Parse category title from URL or direct input.

    Returns the category title with 'Category:' prefix, or None if invalid.
    """
    category_input = category_input.strip()

    # Handle URL format: https://en.wikipedia.org/wiki/Category:Example
    if "wikipedia.org" in category_input:
        match = re.search(r"/wiki/(Category:[^#?]+)", category_input)
        if match:
            return unquote(match.group(1)).replace("_", " ")
        return None

    # Handle direct input - add Category: prefix if missing
    if category_input.startswith("Category:"):
        return category_input.replace("_", " ")

    # Assume it's just the category name
    return f"Category:{category_input.replace('_', ' ')}"


@dataclasses.dataclass
class ArticleWithoutImage:
    """Represents a Wikipedia article that needs an image."""

    title: str
    pageid: int

    @property
    def wikipedia_url(self) -> str:
        """URL to the Wikipedia article."""
        return f"https://en.wikipedia.org/wiki/{self.title.replace(' ', '_')}"

    @property
    def search_url(self) -> str:
        """URL to search for this article in Flickr Mail."""
        return f"/?enwp={quote(self.title)}"


@dataclasses.dataclass
class CategoryResult:
    """Result of a paginated category search."""

    articles: list[ArticleWithoutImage]
    gcmcontinue: str | None


# Common non-content images to ignore when checking if an article has images
NON_CONTENT_IMAGE_PATTERNS = [
    "OOjs UI icon",
    "Commons-logo",
    "Symbol ",
    "Edit-ltr",
    "Ambox ",
    "Question book",
    "Wiki letter",
    "Text document",
    "Folder ",
    "Crystal ",
    "Nuvola ",
    "Gnome-",
    "Disambig ",
    "DAB ",
]


def has_content_image(images: list[dict]) -> bool:
    """Check if an article has a content image (not just UI icons/logos)."""
    for img in images:
        title = img.get("title", "")
        # Skip if it matches any non-content pattern
        is_non_content = any(pattern in title for pattern in NON_CONTENT_IMAGE_PATTERNS)
        if not is_non_content:
            return True
    return False


def get_wikipedia_extract(title: str) -> str:
    """Get the first paragraph extract of a Wikipedia article."""
    params = {
        "action": "query",
        "prop": "extracts",
        "exintro": "true",
        "explaintext": "true",
        "titles": title,
        "format": "json",
    }
    headers = {"User-Agent": WIKIMEDIA_USER_AGENT}
    try:
        r = requests.get(WIKIPEDIA_API, params=params, headers=headers)
        data = r.json()
        pages = data.get("query", {}).get("pages", {})
        for page in pages.values():
            return page.get("extract", "")
    except Exception:
        pass
    return ""


def get_articles_without_images(
    category: str,
    limit: int = 200,
    gcmcontinue: str | None = None,
) -> CategoryResult:
    """Get articles in a category that don't have images.

    Uses generator=categorymembers with prop=images to efficiently check
    multiple articles in a single API request, following continuation until
    the limit is reached or all category members have been processed.
    """
    params = {
        "action": "query",
        "generator": "categorymembers",
        "gcmtitle": category,
        "gcmtype": "page",  # Only articles, not subcategories or files
        "gcmnamespace": "0",  # Main namespace only
        "gcmlimit": "50",  # Small batches so images fit in one response
        "prop": "images",
        "imlimit": "max",
        "format": "json",
    }

    headers = {"User-Agent": WIKIMEDIA_USER_AGENT}
    articles_without_images: list[ArticleWithoutImage] = []
    seen_pageids: set[int] = set()
    next_gcmcontinue: str | None = None

    # Build initial continue params from the external pagination token
    continue_params: dict[str, str] = {}
    if gcmcontinue:
        continue_params = {"gcmcontinue": gcmcontinue, "continue": "gcmcontinue||"}

    while True:
        request_params = params.copy()
        request_params.update(continue_params)

        try:
            response = requests.get(
                WIKIPEDIA_API, params=request_params, headers=headers, timeout=30
            )
            response.raise_for_status()
            data = response.json()
        except (requests.RequestException, json.JSONDecodeError) as e:
            print(f"Wikipedia API error: {e}")
            break

        pages = data.get("query", {}).get("pages", {})
        for page in pages.values():
            pageid = page.get("pageid", 0)
            if not pageid or pageid in seen_pageids:
                continue
            seen_pageids.add(pageid)

            images = page.get("images", [])

            # Skip if page has content images (not just UI icons)
            if has_content_image(images):
                continue

            title = page.get("title", "")
            if title:
                articles_without_images.append(
                    ArticleWithoutImage(title=title, pageid=pageid)
                )

        api_continue = data.get("continue")
        if not api_continue:
            break

        # Only stop at generator boundaries where we have a resumable token
        gcmc = api_continue.get("gcmcontinue")
        if gcmc and len(articles_without_images) >= limit:
            next_gcmcontinue = gcmc
            break

        continue_params = api_continue

    # Sort by title for consistent display
    articles_without_images.sort(key=lambda a: a.title)
    return CategoryResult(
        articles=articles_without_images,
        gcmcontinue=next_gcmcontinue,
    )


def is_valid_flickr_image_url(url: str) -> bool:
    """Check if URL is a valid Flickr static image URL."""
    valid_prefixes = (
        "https://live.staticflickr.com/",
        "https://farm",  # farm1.staticflickr.com, farm2.staticflickr.com, etc.
        "https://c1.staticflickr.com/",
        "https://c2.staticflickr.com/",
    )
    if not url.startswith(valid_prefixes):
        return False
    # For farm URLs, verify the domain pattern
    if url.startswith("https://farm"):
        if ".staticflickr.com/" not in url:
            return False
    return True


def search_flickr(search_term: str, page: int = 1) -> SearchResult:
    """Search Flickr for photos matching the search term."""
    encoded_term = quote(search_term)
    url = f"https://flickr.com/search/?view_all=1&text={encoded_term}&page={page}"

    response = requests.get(url, headers=BROWSER_HEADERS)
    response.raise_for_status()

    return parse_flickr_search_results(response.text, page)


def parse_flickr_search_results(html: str, page: int = 1) -> SearchResult:
    """Parse Flickr search results HTML and extract photo data."""
    empty_result = SearchResult(
        photos=[], total_photos=0, current_page=page, total_pages=0
    )

    # Find the modelExport JSON embedded in the page
    start = html.find("modelExport:")
    if start == -1:
        return empty_result

    start += len("modelExport:")
    while html[start].isspace():
        start += 1

    # Parse the JSON by counting braces
    brace_count = 0
    i = start
    in_string = False
    escape_next = False

    while i < len(html):
        char = html[i]

        if escape_next:
            escape_next = False
            i += 1
            continue

        if char == "\\" and in_string:
            escape_next = True
            i += 1
            continue

        if char == '"' and not escape_next:
            in_string = not in_string
        elif not in_string:
            if char == "{":
                brace_count += 1
            elif char == "}":
                brace_count -= 1
                if brace_count == 0:
                    json_str = html[start : i + 1]
                    break
        i += 1
    else:
        return empty_result

    try:
        data = json.loads(json_str)
    except json.JSONDecodeError:
        return empty_result

    # Extract photos from the parsed data
    photos: list[FlickrPhoto] = []

    main = data.get("main", {})
    photos_models = main.get("search-photos-lite-models", [])

    if not photos_models:
        return empty_result

    model_data = photos_models[0].get("data", {})
    photos_container = model_data.get("photos", {}).get("data", {})
    photos_data = photos_container.get("_data", [])
    total_photos = photos_container.get("totalItems", 0)

    # Calculate total pages (Flickr caps at 4000 results)
    total_pages = min(total_photos, 4000) // PHOTOS_PER_PAGE
    if min(total_photos, 4000) % PHOTOS_PER_PAGE:
        total_pages += 1

    for photo_entry in photos_data:
        # Skip None entries (placeholders from pagination)
        if photo_entry is None:
            continue

        pd = photo_entry.get("data", {})
        if not pd:
            continue

        sizes = pd.get("sizes", {}).get("data", {})
        thumb_data = sizes.get("q", sizes.get("sq", {})).get("data", {})
        medium_data = sizes.get("n", sizes.get("m", {})).get("data", {})

        thumb_url = thumb_data.get("url", "")
        medium_url = medium_data.get("url", "")

        # Ensure URLs have protocol
        if thumb_url.startswith("//"):
            thumb_url = "https:" + thumb_url
        if medium_url.startswith("//"):
            medium_url = "https:" + medium_url

        photos.append(
            FlickrPhoto(
                id=str(pd.get("id", "")),
                title=pd.get("title", ""),
                path_alias=pd.get("pathAlias", ""),
                owner_nsid=pd.get("ownerNsid", ""),
                username=pd.get("username", ""),
                realname=pd.get("realname", ""),
                license=pd.get("license", 0),
                thumb_url=thumb_url,
                medium_url=medium_url,
            )
        )

    return SearchResult(
        photos=photos,
        total_photos=total_photos,
        current_page=page,
        total_pages=total_pages,
    )


def log_interaction(
    interaction_type: str,
    query: str | None = None,
    flickr_url: str | None = None,
    wikipedia_url: str | None = None,
) -> None:
    """Log a user interaction to the database."""
    forwarded_for = flask.request.headers.get("X-Forwarded-For")
    ip_address = forwarded_for.split(",")[0].strip() if forwarded_for else flask.request.remote_addr
    user_agent = flask.request.headers.get("User-Agent")
    session = get_session()
    try:
        entry = InteractionLog(
            timestamp=int(time.time()),
            interaction_type=interaction_type,
            ip_address=ip_address,
            user_agent=user_agent,
            query=query,
            flickr_url=flickr_url,
            wikipedia_url=wikipedia_url,
        )
        session.add(entry)
        session.commit()
    finally:
        session.close()


@app.errorhandler(werkzeug.exceptions.InternalServerError)
def exception_handler(e: werkzeug.exceptions.InternalServerError) -> tuple[str, int]:
    """Handle exception."""
    exec_type, exc_value, current_traceback = sys.exc_info()
    assert exc_value
    tb = DebugTraceback(exc_value)

    summary = tb.render_traceback_html(include_title=False)
    exc_lines = "".join(tb._te.format_exception_only())

    last_frame = list(traceback.walk_tb(current_traceback))[-1][0]
    last_frame_args = inspect.getargs(last_frame.f_code)

    return (
        flask.render_template(
            "show_error.html",
            plaintext=tb.render_traceback_text(),
            exception=exc_lines,
            exception_type=tb._te.exc_type.__name__,
            summary=summary,
            last_frame=last_frame,
            last_frame_args=last_frame_args,
        ),
        500,
    )


@app.route("/")
def start() -> str:
    """Start form."""
    enwp = flask.request.args.get("enwp")
    if not enwp:
        recent_uploads, total_uploads = get_recent_commons_uploads()
        return flask.render_template(
            "combined.html", recent_uploads=recent_uploads, total_uploads=total_uploads
        )
    enwp = enwp.strip()
    if not enwp:
        recent_uploads, total_uploads = get_recent_commons_uploads()
        return flask.render_template(
            "combined.html", recent_uploads=recent_uploads, total_uploads=total_uploads
        )

    input_is = "url" if enwiki in enwp else "title"

    wikipedia_url: str
    wiki_part1: str
    wiki_part2: str
    if input_is == "url":
        start = enwp.find(enwiki) + len(enwiki)
        wiki_part2 = unquote(enwp[start:])
        name = wiki_part2
        wiki_part1 = enwp[:start]
        wikipedia_url = enwp
    else:
        name = enwp
        wiki_part1 = "https://" + enwiki
        wiki_part2 = name.replace(" ", "_")
        wikipedia_url = wiki_part1 + wiki_part2

    # Remove disambiguation suffix like "(academic)" for Flickr search
    name = name.replace("_", " ")
    if " (" in name:
        name = name[: name.find(" (")]

    # Get category param if coming from category search
    cat = flask.request.args.get("cat")

    # Allow overriding the Flickr search term (default includes quotes for phrase search)
    flickr_search = flask.request.args.get("flickr_search") or f'"{name}"'

    flickr_url = flask.request.args.get("flickr")
    if not flickr_url:
        # Search Flickr for photos
        page = flask.request.args.get("page", 1, type=int)
        page = max(1, page)  # Ensure page is at least 1
        if page == 1:
            log_interaction("search_article", query=flickr_search, wikipedia_url=wikipedia_url)
        search_result = search_flickr(flickr_search, page)

        # If no results and using default search, retry without middle initial
        if not search_result.photos and not flask.request.args.get("flickr_search"):
            without_middle = re.sub(r" [A-Z]\. ", " ", name)
            if without_middle != name:
                flickr_search = f'"{without_middle}"'
                search_result = search_flickr(flickr_search, page)

        wikipedia_extract = get_wikipedia_extract(wiki_part2)

        return flask.render_template(
            "combined.html",
            name=name,
            enwp=enwp,
            search_result=search_result,
            cat=cat,
            flickr_search=flickr_search,
            wikipedia_extract=wikipedia_extract,
        )

    if "/in/" in flickr_url:
        flickr_url = flickr_url[: flickr_url.find("/in/")]

    flickr_start = "https://flickr.com/photos/"

    assert flickr_url.startswith(flickr_start)
    flickr_username = flickr_url[
        len(flickr_start) : flickr_url.find("/", len(flickr_start))
    ]

    nsid = flickr_usrename_to_nsid(flickr_username)
    assert nsid
    print(nsid)

    # Get optional image URL for display, validate it's from Flickr
    img_url = flask.request.args.get("img")
    if img_url and not is_valid_flickr_image_url(img_url):
        img_url = None

    # Get flickr_user name and build profile URL
    flickr_user = flask.request.args.get("flickr_user", "")
    flickr_user_url = f"https://www.flickr.com/photos/{flickr_username}/"

    # Check for previous messages to this user
    previous_messages = get_previous_messages(flickr_user, flickr_username)

    # Get license code if provided
    license_code = flask.request.args.get("license", type=int)
    license_name = (
        FLICKR_LICENSES.get(license_code, "") if license_code is not None else ""
    )

    is_free_license = license_code in FREE_LICENSES
    is_nonfree_cc = license_code in NONFREE_CC_LICENSES

    # For free licenses, show upload options instead of message
    if is_free_license:
        return flask.render_template(
            "combined.html",
            name=name,
            enwp=enwp,
            flickr_url=flickr_url,
            img_url=img_url,
            license_code=license_code,
            license_name=license_name,
            is_free_license=True,
            wikipedia_url=wikipedia_url,
            flickr_user=flickr_user,
            flickr_user_url=flickr_user_url,
            cat=cat,
            previous_messages=previous_messages,
            flickr_search=flickr_search,
        )

    log_interaction(
        "generate_message",
        query=name,
        flickr_url=flickr_url,
        wikipedia_url=wikipedia_url,
    )

    msg = flask.render_template(
        "message.jinja",
        flickr_url=flickr_url,
        enwp=enwp,
        wikipedia_url=wikipedia_url,
        name=name,
        wiki_part1=wiki_part1,
        wiki_part2=wiki_part2,
        is_nonfree_cc=is_nonfree_cc,
        license_name=license_name,
    )

    subject = f"Request to use your photo of {name} on Wikipedia"

    lines = [line for line in msg.strip().split("\n\n") if line.strip()]

    return flask.render_template(
        "combined.html",
        name=name,
        enwp=enwp,
        flickr_url=flickr_url,
        subject=subject,
        lines=lines,
        nsid=nsid,
        img_url=img_url,
        license_code=license_code,
        license_name=license_name,
        flickr_user=flickr_user,
        flickr_user_url=flickr_user_url,
        cat=cat,
        previous_messages=previous_messages,
        flickr_search=flickr_search,
    )


@app.route("/category")
def category_search() -> str:
    """Find articles in a Wikipedia category that need images."""
    cat = flask.request.args.get("cat", "").strip()

    if not cat:
        return flask.render_template("category.html")

    category = parse_category_input(cat)
    if not category:
        return flask.render_template(
            "category.html",
            error="Invalid category format. Please enter a category name or URL.",
            cat=cat,
        )

    log_interaction("search_category", query=category)
    gcmcontinue = flask.request.args.get("gcmcontinue") or None
    result = get_articles_without_images(category, gcmcontinue=gcmcontinue)

    # Get the display name (without Category: prefix)
    category_name = category.replace("Category:", "")

    return flask.render_template(
        "category.html",
        cat=cat,
        category=category,
        category_name=category_name,
        articles=result.articles,
        gcmcontinue=result.gcmcontinue,
    )


def get_params(line_iter: collections.abc.Iterable[str]) -> str:
    """Find and return params from flickr profile page."""
    look_for = 'params: {"isEditingTestimonial":false,'
    return next(line[line.find("{") :] for line in line_iter if look_for in line)


def flickr_usrename_to_nsid(username: str) -> str:
    """Get NSID from flickr username."""
    url = f"https://www.flickr.com/people/{username}/"
    r = requests.get(url, headers=BROWSER_HEADERS)
    params_str = get_params(r.text.splitlines())
    params, _ = json.JSONDecoder().raw_decode(params_str)
    return typing.cast(str, params["nsid"])


if __name__ == "__main__":
    app.run(host="0.0.0.0")