#!/usr/bin/env python3
"""
ZIPAIR Singapore Winter Sale Monitor
Checks ZIPAIR's sitemap for new notifications about Singapore ticket sales.
Sends a push notification via ntfy when detected.

State is persisted in last_seen.txt (committed back to repo by the workflow).
"""

import os
import re
import sys
import json
import time
import urllib.request
import urllib.error
from datetime import datetime

# ── Config (set via environment variables / Gitea secrets) ──────────────────
NTFY_URL    = os.environ.get("NTFY_URL", "https://ntfy.example.com/zipair-alert")
NTFY_TOKEN  = os.environ.get("NTFY_TOKEN", "")   # optional, if your ntfy requires auth
STATE_FILE  = os.environ.get("STATE_FILE", "last_seen.txt")

ZIPAIR_SITEMAP  = "https://www.zipair.net/sitemap.xml"
ZIPAIR_NOTIF    = "https://www.zipair.net/en/notification/{id}"

# Keywords that must ALL appear (case-insensitive) in a notification page
# to trigger an alert. Tune these as needed.
TRIGGER_KEYWORDS = ["singapore", "winter"]

# Browser-like headers to avoid 403
HEADERS = {
    "User-Agent": (
        "Mozilla/5.0 (Windows NT 10.0; Win64; x64) "
        "AppleWebKit/537.36 (KHTML, like Gecko) "
        "Chrome/124.0.0.0 Safari/537.36"
    ),
    "Accept":          "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
    "Accept-Language": "en-US,en;q=0.9",
    "Accept-Encoding": "gzip, deflate, br",
    "Connection":      "keep-alive",
}

# ── Helpers ─────────────────────────────────────────────────────────────────

def fetch(url: str, timeout: int = 15) -> str:
    """Fetch a URL and return the decoded body, or empty string on error."""
    req = urllib.request.Request(url, headers=HEADERS)
    try:
        with urllib.request.urlopen(req, timeout=timeout) as resp:
            raw = resp.read()
            # handle gzip transparently (urlopen usually does, but just in case)
            try:
                import gzip
                return gzip.decompress(raw).decode("utf-8", errors="replace")
            except Exception:
                return raw.decode("utf-8", errors="replace")
    except urllib.error.HTTPError as e:
        print(f"  HTTP {e.code} for {url}", file=sys.stderr)
        return ""
    except Exception as e:
        print(f"  Error fetching {url}: {e}", file=sys.stderr)
        return ""


def get_notification_ids_from_sitemap() -> list[int]:
    """Parse the ZIPAIR sitemap and return all notification IDs found."""
    print("Fetching sitemap …")
    xml = fetch(ZIPAIR_SITEMAP)
    if not xml:
        print("  Sitemap unavailable.", file=sys.stderr)
        return []
    ids = [int(m) for m in re.findall(r"/notification/(\d+)", xml)]
    ids = sorted(set(ids))
    print(f"  Found {len(ids)} notification IDs in sitemap (max={ids[-1] if ids else 'n/a'})")
    return ids


def read_last_seen() -> int:
    """Read the last-seen notification ID from the state file."""
    try:
        with open(STATE_FILE) as f:
            return int(f.read().strip())
    except Exception:
        return 0


def write_last_seen(n: int):
    """Persist the last-seen notification ID."""
    with open(STATE_FILE, "w") as f:
        f.write(str(n))
    print(f"State updated: last_seen = {n}")


def matches_keywords(text: str) -> bool:
    """Return True if all TRIGGER_KEYWORDS appear in text."""
    lower = text.lower()
    return all(kw in lower for kw in TRIGGER_KEYWORDS)


def send_ntfy(notif_id: int, snippet: str):
    """Fire a push notification via ntfy."""
    title   = "✈️ ZIPAIR SIN→TYO Tickets On Sale!"
    message = (
        f"A new ZIPAIR announcement about Singapore winter sales was detected "
        f"(notification #{notif_id}). "
        f"Check: https://www.zipair.net/en/notification/{notif_id}"
    )
    payload = json.dumps({
        "topic":    NTFY_URL.rstrip("/").rsplit("/", 1)[-1],
        "title":    title,
        "message":  message,
        "priority": 5,
        "tags":     ["airplane", "moneybag"],
        "click":    f"https://www.zipair.net/en/notification/{notif_id}",
        "actions": [{
            "action": "view",
            "label":  "Open ZIPAIR",
            "url":    f"https://www.zipair.net/en/notification/{notif_id}",
        }],
    }).encode()

    # Build the POST request to the ntfy server base URL
    base_url = NTFY_URL.rstrip("/").rsplit("/", 1)[0]
    req = urllib.request.Request(
        f"{base_url}/",
        data=payload,
        headers={"Content-Type": "application/json"},
        method="POST",
    )
    if NTFY_TOKEN:
        req.add_header("Authorization", f"Bearer {NTFY_TOKEN}")

    try:
        with urllib.request.urlopen(req, timeout=10) as resp:
            print(f"ntfy response: {resp.status} {resp.reason}")
    except Exception as e:
        print(f"Failed to send ntfy: {e}", file=sys.stderr)
        sys.exit(1)


# ── Main ────────────────────────────────────────────────────────────────────

def main():
    print(f"\n[{datetime.utcnow().isoformat()}Z] ZIPAIR monitor starting …")
    print(f"  Keywords : {TRIGGER_KEYWORDS}")
    print(f"  ntfy URL : {NTFY_URL}")

    last_seen = read_last_seen()
    print(f"  Last seen notification ID: {last_seen}")

    ids = get_notification_ids_from_sitemap()
    if not ids:
        print("No notification IDs found; exiting.")
        sys.exit(0)

    new_ids = [i for i in ids if i > last_seen]
    if not new_ids:
        print("No new notifications since last check. All good.")
        write_last_seen(max(ids))
        sys.exit(0)

    print(f"  {len(new_ids)} new notification(s) to check: {new_ids}")
    found_match = None

    for nid in new_ids:
        url = ZIPAIR_NOTIF.format(id=nid)
        print(f"  Fetching notification #{nid} …")
        text = fetch(url)
        time.sleep(1)  # be polite

        if not text:
            print(f"    Could not fetch #{nid}, skipping.")
            continue

        if matches_keywords(text):
            print(f"  ✅ MATCH in notification #{nid}!")
            # Grab a short snippet for context
            lower = text.lower()
            pos = lower.find("singapore")
            snippet = text[max(0, pos - 50): pos + 200].strip()
            found_match = (nid, snippet)
            break
        else:
            print(f"    No match in #{nid}.")

    # Always advance the state to the latest ID we've seen
    write_last_seen(max(ids))

    if found_match:
        nid, snippet = found_match
        print(f"\n🚨 Sending ntfy push for notification #{nid}")
        send_ntfy(nid, snippet)
        print("Done — notification sent!")
    else:
        print("\nNo Singapore winter sale announcement found yet.")

    sys.exit(0)


if __name__ == "__main__":
    main()