feed_common.py

"""Shared helpers for free/paid chapter feed generators.

This module is intentionally limited to generator-level rules:
- source-mode/scope detection from mappings
- completion-state gating for novel-scoped fetches
- shared NSFW marker detection
- shared item sorting

It does not write RSS XML and does not build free/paid RSS items, so the XML
shape stays owned by free_feed_generator.py and paid_feed_generator.py.
"""

from __future__ import annotations

import datetime
import json
import os
import re

import feedparser
from pathlib import Path
from typing import Any
from urllib.request import Request, urlopen

from novel_mappings import HOSTING_SITE_DATA
from config_loader import get_integration_raw_url, get_runtime_fetch_config, get_source_mode_value

NSFW_PAREN_RE = re.compile(r"\([^)]*\b(?:nsfw|r-?18|18\+|h{1,3})\b[^)]*\)", re.I)

FEED_URL_KEYS = {
    "free": "free_feed_url",
    "paid": "paid_feed_url",
}

SOURCE_MODE_KEYS = {
    "free": "free_chapters_source",
    "paid": "paid_chapters_source",
}


def has_nsfw_marker(*texts: str) -> bool:
    for text in texts:
        if text and NSFW_PAREN_RE.search(str(text)):
            return True
    return False


def truthy(value: Any) -> bool:
    if isinstance(value, bool):
        return value
    if value is None:
        return False

    text = str(value).strip().casefold()
    return text in {"1", "true", "yes", "y", "on"}


def normalize_title_key(title: str) -> str:
    return re.sub(r"\s+", " ", str(title or "")).strip().casefold()


def _parsed_time_to_utc(tt: Any) -> datetime.datetime | None:
    if not tt:
        return None
    try:
        return datetime.datetime(*tt[:6], tzinfo=datetime.timezone.utc)
    except Exception:
        return None


def parsed_entry_pub_date(entry: Any) -> datetime.datetime | None:
    tt = getattr(entry, "published_parsed", None) or getattr(entry, "updated_parsed", None)
    if not tt and isinstance(entry, dict):
        tt = entry.get("published_parsed") or entry.get("updated_parsed")
    return _parsed_time_to_utc(tt)


def parsed_feed_build_date(parsed_feed: Any) -> datetime.datetime | None:
    feed = getattr(parsed_feed, "feed", None) or {}
    for key in ("updated_parsed", "published_parsed", "created_parsed"):
        tt = getattr(feed, key, None)
        if not tt and isinstance(feed, dict):
            tt = feed.get(key)
        dt = _parsed_time_to_utc(tt)
        if dt is not None:
            return dt
    return None


def feed_looks_capped_at_current_batch(parsed_feed: Any) -> bool:
    """Return True when a 100-row host feed may be hiding same-time leftovers.

    Mistmint's public feed shows 100 items. If the oldest visible item still has
    the same timestamp as the channel build time or newest entry, there may be
    more same-timestamp rows beyond the cap.
    """

    entries = list(getattr(parsed_feed, "entries", []) or [])
    if len(entries) < 100:
        return False

    oldest_dt = parsed_entry_pub_date(entries[-1])
    if oldest_dt is None:
        return False

    build_dt = parsed_feed_build_date(parsed_feed)
    if build_dt is not None and oldest_dt == build_dt:
        return True

    newest_dt = parsed_entry_pub_date(entries[0])
    return newest_dt is not None and oldest_dt == newest_dt


def entry_matches_chapter_type(utils: dict[str, Any], entry: Any, chapter_type: str) -> bool:
    """Return whether one source entry belongs in this generated feed.

    Default is True to preserve old behavior. Hosts with mixed free/paid RSS
    feeds can expose one of these hooks in their utils dict:
      - entry_matches_chapter_type(entry, "free"/"paid")
      - is_free_entry(entry) / is_paid_entry(entry)
      - entry_is_free(entry) / entry_is_paid(entry)
    """

    chapter_type = str(chapter_type or "").strip().casefold()
    utils = utils or {}

    checker = utils.get("entry_matches_chapter_type")
    if callable(checker):
        try:
            return bool(checker(entry, chapter_type))
        except TypeError:
            return bool(checker(entry))
        except Exception as exc:
            print(f"Warning: entry_matches_chapter_type failed for {chapter_type}: {exc}")
            return True

    for name in (f"is_{chapter_type}_entry", f"entry_is_{chapter_type}"):
        checker = utils.get(name)
        if callable(checker):
            try:
                return bool(checker(entry))
            except Exception as exc:
                print(f"Warning: {name} failed: {exc}")
                return True

    return True


# ---------------- Fetch/Concurrency Helpers ----------------

def _safe_int(value: Any, default: int | None = None) -> int | None:
    try:
        return int(str(value).strip())
    except Exception:
        return default


def _first_runtime_int(fetch_cfg: dict[str, Any], keys: tuple[str, ...]) -> int | None:
    for key in keys:
        if key in fetch_cfg and str(fetch_cfg.get(key, "")).strip() != "":
            value = _safe_int(fetch_cfg.get(key))
            if value is not None:
                return value
    return None


def chapter_fetch_concurrency(
    chapter_type: str = "",
    default: int = 6,
    *,
    max_value: int | None = None,
) -> int:
    """Return the concurrency limit for novel-scoped chapter fetches.

    Priority:
      1. FREE_FETCH_CONCURRENCY / PAID_FETCH_CONCURRENCY env
      2. CHAPTER_FETCH_CONCURRENCY env
      3. config/runtime.json free_fetch_concurrency / paid_fetch_concurrency
      4. config/runtime.json chapter_fetch_concurrency
      5. default
    """

    chapter_type_upper = str(chapter_type or "").strip().upper()
    chapter_type_lower = str(chapter_type or "").strip().casefold()

    env_keys: list[str] = []
    if chapter_type_upper:
        env_keys.append(f"{chapter_type_upper}_FETCH_CONCURRENCY")
    env_keys.append("CHAPTER_FETCH_CONCURRENCY")

    value: int | None = None
    for key in env_keys:
        raw = str(os.getenv(key, "") or "").strip()
        if raw:
            value = _safe_int(raw)
            if value is not None:
                break

    fetch_cfg = get_runtime_fetch_config()

    if value is None:
        config_keys: list[str] = []
        if chapter_type_lower:
            config_keys.append(f"{chapter_type_lower}_fetch_concurrency")
        config_keys.append("chapter_fetch_concurrency")
        value = _first_runtime_int(fetch_cfg, tuple(config_keys))

    if value is None:
        value = default

    value = max(1, int(value))

    config_max = _first_runtime_int(
        fetch_cfg,
        tuple(
            key
            for key in (
                f"max_{chapter_type_lower}_fetch_concurrency" if chapter_type_lower else "",
                "max_chapter_fetch_concurrency",
            )
            if key
        ),
    )

    limits = [candidate for candidate in (max_value, config_max) if candidate is not None]
    if limits:
        value = min(value, max(1, min(int(candidate) for candidate in limits)))

    return value


async def fetch_parsed_feed_async(session: Any, feed_url: str, *, semaphore: Any, label: str = "Feed"):
    """Fetch one RSS/Atom feed with aiohttp and return a feedparser result."""

    async with semaphore:
        try:
            async with session.get(feed_url, timeout=30) as resp:
                if resp.status >= 400:
                    print(f"{label} fetch failed: {feed_url} → HTTP {resp.status}")
                    return feedparser.parse("")
                text = await resp.text()
        except Exception as exc:
            print(f"{label} fetch failed: {feed_url} → {exc}")
            return feedparser.parse("")

    return feedparser.parse(text)


# ---------------- Source Scope Helpers ----------------

def host_data_for(host: str) -> dict[str, Any]:
    return HOSTING_SITE_DATA.get(host, {}) or {}


def novels_for_host(host: str) -> dict[str, dict[str, Any]]:
    return host_data_for(host).get("novels", {}) or {}


def normalize_chapter_source_mode(value: Any) -> str:
    """Normalize chapter source mode names used in host TOML/env/config.

    Supported canonical modes:
    - feed: use only RSS/feed-style source
    - api: use only chapter API/data source
    - feed_api: use feed first, then API only when the feed looks capped
    """

    raw = str(value or "").strip().casefold().replace("-", "_").replace("+", "_")
    raw = re.sub(r"\s+", "_", raw)

    aliases = {
        "feed": "feed",
        "rss": "feed",
        "api": "api",
        "feed_api": "feed_api",
        "api_feed": "feed_api",
        "feed_with_api": "feed_api",
        "feed_with_api_fallback": "feed_api",
        "feed_api_fallback": "feed_api",
        "hybrid": "feed_api",
    }

    return aliases.get(raw, "")


def chapter_source_mode(host: str, chapter_type: str) -> str:
    """Return host source mode for this chapter type.

    Modes:
    - feed: use the feed/RSS-style source only
    - api: use the chapter API/data source only
    - feed_api: use feed, then API only when the feed looks capped

    If the host TOML does not say explicitly:
    - free defaults to feed, unless there is no free_feed_url but there is a chapters_api_url
    - paid defaults to feed when paid_feed_url exists, otherwise api
    """

    chapter_type = str(chapter_type or "").strip().casefold()
    host_data = host_data_for(host)

    key = SOURCE_MODE_KEYS.get(chapter_type, "")
    raw = get_source_mode_value(host, key, host_data.get(key, ""))
    mode = normalize_chapter_source_mode(raw)
    if mode:
        return mode

    if chapter_type == "free":
        return "api" if host_data.get("chapters_api_url") and not host_data.get("free_feed_url") else "feed"

    if chapter_type == "paid":
        return "feed" if host_data.get("paid_feed_url") else "api"

    return "feed"


def chapter_source_uses_feed(mode: str) -> bool:
    return normalize_chapter_source_mode(mode) in {"feed", "feed_api"}


def chapter_source_uses_api(mode: str) -> bool:
    return normalize_chapter_source_mode(mode) in {"api", "feed_api"}


def host_level_feed_url(host: str, chapter_type: str) -> str:
    """Return only the host-level feed URL, without novel fallback."""

    key = FEED_URL_KEYS.get(str(chapter_type or "").strip().casefold(), "")
    if not key:
        return ""
    return str(host_data_for(host).get(key, "") or "").strip()


def slug_from_url(url: str) -> str:
    value = str(url or "").strip().rstrip("/")
    if not value:
        return ""
    return value.split("/")[-1]


def fill_novel_template(template: str, novel_title: str, details: dict[str, Any]) -> str:
    value = str(template or "")

    novel_url = str(details.get("novel_url") or "").strip()
    slug = str(details.get("slug") or slug_from_url(novel_url) or "").strip()
    novel_id = str(details.get("novel_id") or details.get("id") or "").strip()
    short_code = str(details.get("short_code") or "").strip()

    replacements = {
        "{slug}": slug,
        "{novel_slug}": slug,
        "{novel_url_slug}": slug,
        "{novel_id}": novel_id,
        "{id}": novel_id,
        "{novel_url}": novel_url,
        "{title}": novel_title,
        "{short_code}": short_code,
    }

    for key, replacement in replacements.items():
        value = value.replace(key, replacement)

    return value.strip()


def resolved_novel_feed_url(host: str, novel_title: str, details: dict[str, Any], chapter_type: str) -> str:
    raw = novel_level_feed_url(details, chapter_type) or host_level_feed_url(host, chapter_type)
    return fill_novel_template(raw, novel_title, details)


def novel_level_feed_url(details: dict[str, Any], chapter_type: str) -> str:
    """Return only the novel-level feed URL, without host fallback."""

    key = FEED_URL_KEYS.get(str(chapter_type or "").strip().casefold(), "")
    if not key:
        return ""
    return str((details or {}).get(key, "") or "").strip()


def chapters_api_template(host: str, details: dict[str, Any] | None = None) -> str:
    details = details or {}
    return str(details.get("chapters_api_url") or host_data_for(host).get("chapters_api_url") or "").strip()


NOVEL_URL_MARKERS = (
    "{slug}",
    "{novel_slug}",
    "{novel_url_slug}",
    "{novel_id}",
    "{id}",
    "{novel_url}",
    "{title}",
    "{short_code}",
)


def needs_novel_value(template: str) -> bool:
    lowered = str(template or "").casefold()
    return any(marker in lowered for marker in NOVEL_URL_MARKERS)

def api_source_scope(host: str, details: dict[str, Any] | None = None) -> str:
    """Return "novel" or "host" for a chapters API template.

    A host-level template can still be novel-scoped if it needs a novel slug/id/url.
    Example: chapters_api_url = ".../slug/{slug}/chapters" is novel-scoped.
    """

    template = chapters_api_template(host, details)
    if not template:
        return ""

    if needs_novel_value(template):
        return "novel"

    # If the API URL is defined directly on one novel, treat it as novel-scoped.
    if details and details.get("chapters_api_url"):
        return "novel"

    return "host"


def source_scope_for(host: str, novel_title: str, details: dict[str, Any], chapter_type: str) -> str:
    """Return one of host_feed, novel_feed, host_api, novel_api, or "".

    This reads the mapping shape instead of using novel→host fallback getters,
    so the generator can tell where a source lives.
    """

    mode = chapter_source_mode(host, chapter_type)

    if chapter_source_uses_feed(mode):
        novel_feed = novel_level_feed_url(details, chapter_type)
        if novel_feed:
            return "novel_feed"

        host_feed = host_level_feed_url(host, chapter_type)
        if host_feed:
            return "novel_feed" if needs_novel_value(host_feed) else "host_feed"

    if chapter_source_uses_api(mode):
        scope = api_source_scope(host, details)
        if scope == "novel":
            return "novel_api"
        if scope == "host":
            return "host_api"
        return ""

    return ""


# ---------------- Completion State Gate ----------------

def completion_state_url() -> str:
    env_url = str(os.getenv("COMPLETION_STATE_URL") or "").strip()

    if env_url:
        return env_url

    integration = os.getenv("DISCORD_INTEGRATION", "discord_webhook").strip() or "discord_webhook"
    return get_integration_raw_url(integration, "state", "state.json")


def completion_state_path() -> str:
    return str(
        os.getenv("COMPLETION_STATE_PATH")
        or os.getenv("DISCORD_WEBHOOK_STATE_PATH")
        or ""
    ).strip()


def _load_json_path(path: str) -> dict[str, Any]:
    p = Path(path)
    if not p.exists():
        print(f"Warning: completion state path does not exist: {path}")
        return {}

    try:
        data = json.loads(p.read_text(encoding="utf-8"))
    except Exception as e:
        print(f"Warning: could not read completion state path {path}: {e}")
        return {}

    if not isinstance(data, dict):
        print(f"Warning: completion state is not a JSON object: {path}")
        return {}

    return data


def _load_json_url(url: str) -> dict[str, Any]:
    if not url:
        return {}

    try:
        req = Request(url, headers={"User-Agent": "rss-feed-generator/1.0"})
        with urlopen(req, timeout=20) as resp:
            status = getattr(resp, "status", 200)
            if status != 200:
                print(f"Warning: completion state returned HTTP {status}: {url}")
                return {}
            data = json.loads(resp.read().decode("utf-8"))
    except Exception as e:
        print(f"Warning: could not fetch completion state {url}: {e}")
        return {}

    if not isinstance(data, dict):
        print(f"Warning: completion state is not a JSON object: {url}")
        return {}

    return data


def load_completion_state() -> dict[str, Any]:
    """Load canonical discord-webhook/state.json.

    Path env wins for local testing; otherwise use integrations.json URL.
    Missing/unreadable state returns {}, which means "do not skip anything".
    """

    path = completion_state_path()
    if path:
        return _load_json_path(path)

    return _load_json_url(completion_state_url())


def completion_key_for(chapter_type: str, novel_details: dict[str, Any]) -> str:
    chapter_type = str(chapter_type or "").strip().casefold()

    if chapter_type == "paid":
        return "paid_completion"

    if chapter_type == "free":
        return "free_completion" if (novel_details or {}).get("paid_feed") else "only_free_completion"

    return ""


def completion_announced(
    novel_title: str,
    chapter_type: str,
    novel_details: dict[str, Any],
    *,
    state: dict[str, Any] | None = None,
) -> bool:
    state = state if isinstance(state, dict) else {}
    key = completion_key_for(chapter_type, novel_details)
    if not key:
        return False

    wanted = normalize_title_key(novel_title)
    for title, record in state.items():
        if normalize_title_key(title) != wanted:
            continue
        return isinstance(record, dict) and bool(record.get(key))

    return False


def should_skip_completed(
    novel_title: str,
    chapter_type: str,
    novel_details: dict[str, Any],
    *,
    state: dict[str, Any] | None = None,
    force: bool = False,
) -> bool:
    if force:
        return False
    return completion_announced(novel_title, chapter_type, novel_details, state=state)


# ---------------- Shared Feed Sorting ----------------

def _normalized_pubdate(item):
    dt = getattr(item, "pubDate", None)

    if not isinstance(dt, datetime.datetime):
        return datetime.datetime.min.replace(tzinfo=datetime.timezone.utc)

    if dt.tzinfo is None:
        dt = dt.replace(tzinfo=datetime.timezone.utc)

    return dt.astimezone(datetime.timezone.utc).replace(microsecond=0)


def _novel_alpha_sort_key(item):
    return (
        getattr(item, "host", "").casefold(),
        getattr(item, "title", "").casefold(),
    )


def _chapter_sort_key(item):
    from host_utils import get_host_utils

    return get_host_utils(getattr(item, "host", "")).get(
        "chapter_num", lambda s: (0,)
    )(getattr(item, "chapter", ""))


def sort_feed_items(items):
    """
    Sort newest pubDate first.

    Tie-breakers:
      1. host/title alphabetical
      2. chapter number newest first within the same novel/date
    """
    # weakest tie-breaker first
    items.sort(key=_chapter_sort_key, reverse=True)

    # then alphabetical novel tie-breaker
    items.sort(key=_novel_alpha_sort_key)

    # strongest sort last
    items.sort(key=_normalized_pubdate, reverse=True)