# utils/parser_fast.py
from typing import Any, Dict, List, Tuple, Optional

def pick_image_url(item: Dict[str, Any]) -> Optional[str]:
    cands = ((item.get("image_versions2") or {}).get("candidates") or [])
    return cands[0].get("url") if cands else None

def pick_video_url(item: Dict[str, Any]) -> Optional[str]:
    # choose the largest height (usually last or explicitly max)
    vv = item.get("video_versions") or []
    if not vv: 
        return None
    # faster than sorted: single pass to get max by height
    best = vv[0]
    bh = best.get("height") or 0
    for v in vv[1:]:
        h = v.get("height") or 0
        if h > bh:
            bh, best = h, v
    return best.get("url")

def normalize_item(it: Dict[str, Any]) -> Dict[str, Any]:
    mt = it.get("media_type")
    if mt == 1:
        media_type = "image"
        url = pick_image_url(it)
        urls = [url] if url else []
    elif mt == 2:
        media_type = "video"
        # put a cover first if exists
        cover = pick_image_url(it)
        vurl = pick_video_url(it)
        urls = ([cover] if cover else []) + ([vurl] if vurl else [])
    elif mt == 8:  # carousel
        media_type = "carousel"
        urls = []
        for child in it.get("carousel_media") or []:
            if child.get("media_type") == 1:
                u = pick_image_url(child)
                if u: urls.append(u)
            elif child.get("media_type") == 2:
                cover = pick_image_url(child)
                vurl = pick_video_url(child)
                if cover: urls.append(cover)
                if vurl: urls.append(vurl)
    else:
        return {}

    return {
        "ig_post_id": str(it.get("pk") or it.get("id") or ""),
        "media_type": media_type,
        "caption": ((it.get("caption") or {}).get("text") or ""),
        "taken_at": int(it.get("taken_at") or 0),
        "thumbnail_url": pick_image_url(it),
        "remote_urls": [u for u in urls if u],
        "code": it.get("code"),
    }

def parse_boxapi_items_fast(items: List[Dict[str, Any]]) -> List[Dict[str, Any]]:
    out = []
    for it in items:
        n = normalize_item(it)
        if n: out.append(n)
    # keep newest first
    out.sort(key=lambda x: x["taken_at"], reverse=True)
    return out