engine_content.py

"""Content module"""
import time
from db import get_service_client
import engine_user
from engineHelper import parse_db_timestamp, upload_media_to_cloudinary

import threading
# In-memory caches (simple dict caches)
_avatar_cache = {}  # username -> (avatar_url, timestamp)
_post_likes_cache = {}  # post_id -> (likes_count, timestamp)
_cache_ttl = 60  # seconds
_cache_lock = threading.Lock()

def _get_cached(cache, key, ttl=None):
    ttl = ttl or _cache_ttl
    with _cache_lock:
        if key in cache:
            value, ts = cache[key]
            if time.time() - ts < ttl:
                return value
            del cache[key]
    return None

def _set_cache(cache, key, value):
    with _cache_lock:
        cache[key] = (value, time.time())

# ========================
# POSTS
# ========================

def create_post(username, content, media_path):
    sb = get_service_client()
    if media_path and media_path.startswith("data:"):
        media_path = upload_media_to_cloudinary(media_path)
    result = sb.table("posts").insert({
        "username": username, "station_name": "", "content": content,
        "media_path": media_path, "comments_count": 0, "likes_count": 0
    }).execute()
    row = result.data[0]
    avatar = engine_user.get_avatar(username)
    return {
        "id": str(row["id"]), "username": username, "content": content,
        "media_path": media_path, "timestamp": str(row["timestamp"]), "comments_count": "0",
        "likes_count": "0", "station_name": "", "avatar": avatar
    }

def delete_post(post_id, username):
    sb = get_service_client()
    # Check ownership
    rows = sb.table("posts").select("id").eq("id", post_id).eq("username", username).execute()
    if not rows.data: return False
    # Cascading deletes handle comments and likes!
    sb.table("posts").delete().eq("id", post_id).eq("username", username).execute()
    return True

def get_feed(viewer=""):
    sb = get_service_client()
    rows = sb.table("posts").select("id, username, content, media_path, timestamp, comments_count, likes_count, station_name").order("timestamp", desc=True).execute()
    
    # Get blocking set
    restricted_users = engine_user.get_blocking_relationship_usernames(viewer) if viewer else set()
    # Normalize restricted users to lowercase for faster case-insensitive lookup
    restricted_users_low = {u.lower() for u in restricted_users if u}
    viewer_low = viewer.lower() if viewer else ""

    # Get station admins for station posts filtering
    unique_stations = list(set(r["station_name"] for r in rows.data if r.get("station_name")))
    station_admin_map = {}
    if unique_stations:
        try:
            import engine_station
            stations_res = sb.table("stations").select("station_name, admin, profile_pic").in_("station_name", unique_stations).execute()
            for sr in stations_res.data:
                station_admin_map[sr["station_name"]] = (sr["admin"], sr["profile_pic"] or "")
        except:
            pass

    results = []
    
    # Pre-fetch likes if viewer is provided
    liked_post_ids = []
    if viewer:
        likes_res = sb.table("likes").select("post_id").eq("username", viewer).execute()
        liked_post_ids = [str(l["post_id"]) for l in likes_res.data]

    # Performance optimization: pre-fetch visibility and follow status for all unique users
    unique_users = list(set(r["username"] for r in rows.data if r.get("username") and not r.get("station_name")))
    
    visibility_map = {}
    following_set_low = set()
    if unique_users:
        try:
            users_res = sb.table("users").select("username, visibility").in_("username", unique_users).execute()
            for ur in users_res.data:
                visibility_map[ur["username"]] = int(ur["visibility"])
            
            if viewer:
                follows_res = sb.table("follows").select("following").eq("follower", viewer).eq("status", 1).in_("following", unique_users).execute()
                following_set_low = {f["following"].lower() for f in follows_res.data}
        except:
            pass

    avatar_map = {}
    if unique_users:
        # Check cache first
        missing_users = []
        for u in unique_users:
            cached = _get_cached(_avatar_cache, u)
            if cached is not None:
                avatar_map[u] = cached
            else:
                missing_users.append(u)
        
        if missing_users:
            try:
                # Batch fetch missing avatars from DB
                users_res = sb.table("users").select("username, avatar").in_("username", missing_users).execute()
                for ur in users_res.data:
                    u_name = ur.get("username")
                    if u_name:
                        av = ur.get("avatar") or ""
                        avatar_map[u_name] = av
                        _set_cache(_avatar_cache, u_name, av)
            except:
                pass

    for r in rows.data:
        # Filtering based on blocks
        post_user = r["username"]
        post_user_low = post_user.lower() if post_user else ""
        station_name = r["station_name"]
        
        # If user is blocked/blocker, skip unless it's the viewer themselves
        if post_user_low in restricted_users_low and post_user_low != viewer_low:
            continue
            
        # Private account check (only for personal posts)
        if not station_name and post_user_low != viewer_low:
            visibility = visibility_map.get(post_user, 1) # Default to public if missing
            if visibility == 0 and post_user_low not in following_set_low:
                continue

        # If it's a station post, check station admin
        if station_name:
            admin, s_avatar = station_admin_map.get(station_name, (None, ""))
            if admin and admin.lower() in restricted_users_low and admin.lower() != viewer_low:
                continue
            r["avatar"] = s_avatar
        else:
            r["avatar"] = avatar_map.get(post_user, "")

        p = {k: str(v) for k, v in r.items()}
        p["timestamp"] = str(parse_db_timestamp(r["timestamp"]))
        p["is_liked"] = p["id"] in liked_post_ids
        results.append(p)
        
    return results


def get_user_posts(username, viewer=""):
    # If blocked, return empty
    if viewer and engine_user.is_blocked_either_way(username, viewer):
        return []

    sb = get_service_client()
    
    # Check target visibility
    if username != viewer:
        try:
            target_res = sb.table("users").select("visibility").eq("username", username).execute()
            if target_res.data:
                visibility = int(target_res.data[0]["visibility"])
                if visibility == 0:
                    # Check if viewer follows
                    status = engine_user.get_follow_status(viewer, username)
                    if status != 1:
                        return []
        except:
            pass

    # Case-insensitive self-check: viewer can always see their own posts
    is_self = False
    if viewer and username and viewer.lower() == username.lower():
        is_self = True
    
    rows = sb.table("posts").select("id, username, station_name, content, media_path, timestamp, comments_count, likes_count").eq("username", username).order("timestamp", desc=True).execute()
    
    # Pre-fetch likes if viewer is provided
    liked_post_ids = []
    if viewer:
        try:
            likes_res = sb.table("likes").select("post_id").eq("username", viewer).eq("isLike", 1).execute()
            liked_post_ids = [str(l["post_id"]) for l in likes_res.data]
        except:
            pass

    # Batch fetch station avatars if any posts are in stations
    unique_stations = list(set(r["station_name"] for r in rows.data if r.get("station_name")))
    station_avatar_map = {}
    if unique_stations:
        try:
            stations_res = sb.table("stations").select("station_name, profile_pic").in_("station_name", unique_stations).execute()
            for sr in stations_res.data:
                s_name = sr.get("station_name")
                if s_name:
                    station_avatar_map[s_name] = sr.get("profile_pic") or ""
        except:
            pass

    # Fetch user avatar
    cached_avatar = _get_cached(_avatar_cache, username)
    if cached_avatar is None:
        cached_avatar = engine_user.get_avatar(username)
        _set_cache(_avatar_cache, username, cached_avatar)
    user_avatar = cached_avatar

    results = []
    for r in rows.data:
        p = {k: str(v) for k, v in r.items()}
        p["timestamp"] = str(parse_db_timestamp(r["timestamp"]))
        p["is_liked"] = p["id"] in liked_post_ids
        
        # If it's a station post, use station avatar
        if r.get("station_name"):
            p["avatar"] = station_avatar_map.get(r["station_name"], "")
        else:
            p["avatar"] = user_avatar
            
        results.append(p)
    return results

def is_liked(post_id, username):
    sb = get_service_client()
    res = sb.table("likes").select("isLike").eq("post_id", post_id).eq("username", username).execute()
    if res.data:
        return str(res.data[0]["isLike"]) == "1"
    return False

# ========================
# LIKES
# ========================

def like_post(post_id, username):
    sb = get_service_client()
    pid = post_id
    rows = sb.table("likes").select("isLike").eq("post_id", pid).eq("username", username).execute()
    if rows.data:
        if str(rows.data[0]["isLike"]) == "1":
            return False
        sb.table("likes").update({"isLike": 1}).eq("post_id", pid).eq("username", username).execute()
        return True
    sb.table("likes").insert({"post_id": pid, "username": username, "isLike": 1}).execute()
    return True

def unlike_post(post_id, username):
    sb = get_service_client()
    pid = post_id
    rows = sb.table("likes").select("isLike").eq("post_id", pid).eq("username", username).execute()
    if not rows.data: return False
    if str(rows.data[0]["isLike"]) == "0":
        return False
    sb.table("likes").update({"isLike": 0}).eq("post_id", pid).eq("username", username).execute()
    return True

def modify_likes(post_id, delta):
    sb = get_service_client()
    rows = sb.table("posts").select("likes_count").eq("id", post_id).execute()
    if not rows.data: return -1
    current = int(rows.data[0]["likes_count"])
    new_count = max(0, current + delta)
    sb.table("posts").update({"likes_count": new_count}).eq("id", post_id).execute()
    # Update cache
    _set_cache(_post_likes_cache, post_id, new_count)
    return new_count

# ========================
# COMMENTS
# ========================

def add_comment(post_id, username, content):
    sb = get_service_client()
    # Database handles timestamp automatically via DEFAULT NOW()
    sb.table("comments").insert({"post_id": post_id, "username": username, "content": content}).execute()
    rows = sb.table("posts").select("comments_count").eq("id", post_id).execute()
    if rows.data:
        sb.table("posts").update({"comments_count": int(rows.data[0]["comments_count"]) + 1}).eq("id", post_id).execute()
    return True

def get_comments(post_id, viewer=""):
    sb = get_service_client()
    rows = sb.table("comments").select("username, content, timestamp").eq("post_id", post_id).order("timestamp", desc=True).execute()
    
    restricted_users = {u.lower() for u in engine_user.get_blocking_relationship_usernames(viewer)} if viewer else set()
    
    results = []
    for r in rows.data:
        if r["username"].lower() in restricted_users:
            continue
        results.append({
            "username": r["username"], 
            "content": r["content"], 
            "timestamp": str(parse_db_timestamp(r["timestamp"]))
        })
    return results

def get_post(post_id, viewer=""):
    sb = get_service_client()
    rows = sb.table("posts").select("*").eq("id", post_id).execute()
    if not rows.data:
        return None
    r = rows.data[0]
    
    # Check blocks
    if viewer:
        if engine_user.is_blocked_either_way(r["username"], viewer):
            return None
        if r["station_name"]:
            import engine_station
            admin = engine_station.get_station_admin(r["station_name"])
            if admin and engine_user.is_blocked_either_way(admin, viewer):
                return None

    # Check visibility: if post owner is private and viewer doesn't follow them
    post_owner = r["username"]
    is_self = viewer and post_owner and viewer.lower() == post_owner.lower()
    
    if viewer and not is_self and not r.get("station_name"):
        owner_res = sb.table("users").select("visibility").eq("username", post_owner).execute()
        if owner_res.data and int(owner_res.data[0]["visibility"]) == 0:
            follows_res = sb.table("follows").select("id").eq("follower", viewer).eq("following", post_owner).eq("status", 1).execute()
            if not follows_res.data:
                return {"restricted": True, "username": post_owner}

    p = {k: str(v) for k, v in r.items()}
    p["timestamp"] = str(parse_db_timestamp(r["timestamp"]))
    
    # Check if liked
    p["is_liked"] = False
    if viewer:
        likes_res = sb.table("likes").select("isLike").eq("post_id", post_id).eq("username", viewer).execute()
        if likes_res.data:
            p["is_liked"] = str(likes_res.data[0]["isLike"]) == "1"

    # Avatar resolution
    if r.get("station_name"):
        import engine_station
        p["avatar"] = engine_station.get_station_profile_pic(r["station_name"])
    else:
        p["avatar"] = engine_user.get_avatar(r["username"])
        
    return p