#!/usr/bin/env python3
"""Download Danbooru posts tagged 'holding_teapot' and convert them to WebP.

Requires ImageMagick's `mogrify` to be installed and on PATH.
"""

import json
import os
import subprocess
import sys
import time
import urllib.parse
import urllib.request

BASE_URL = "https://danbooru.donmai.us/posts"
TAGS = "holding_teapot -animated rating:general score:>=4"
OUT_DIR = "teapots"
IMAGE_EXTS = {"jpg", "jpeg", "png", "gif", "bmp"}
HEADERS = {"User-Agent": "teapot-scraper/1.0"}

os.makedirs(OUT_DIR, exist_ok=True)


def fetch_page(page: int):
    query = urllib.parse.urlencode(
        {"tags": TAGS, "format": "json", "page": page})
    req = urllib.request.Request(f"{BASE_URL}?{query}", headers=HEADERS)
    with urllib.request.urlopen(req) as resp:
        return json.loads(resp.read())


def download(url: str, dest: str):
    req = urllib.request.Request(url, headers=HEADERS)
    with urllib.request.urlopen(req) as resp, open(dest, "wb") as f:
        f.write(resp.read())


def main():
    page = 64  # last page I got, will figure out how to get only posts we don't have later
    while True:
        print(f"Fetching page {page}...")
        try:
            posts = fetch_page(page)
        except Exception as e:
            print(f"Error fetching page {page}: {e}", file=sys.stderr)
            break

        if not posts:
            print("Empty page, stopping.")
            break

        downloaded = []
        for post in posts:
            post_id = post.get("id")
            file_ext = (post.get("file_ext") or "").lower()
            file_url = post.get("file_url")

            if file_ext not in IMAGE_EXTS:
                continue
            if not file_url:
                print(f"  Skipping post {
                      post_id}: no file_url (likely gated/login-only)")
                continue

            dest = os.path.join(OUT_DIR, f"{post_id}.{file_ext}")
            try:
                download(file_url, dest)
                downloaded.append(dest)
                print(f"  Saved {dest}")
            except Exception as e:
                print(f"  Failed to download post {
                      post_id}: {e}", file=sys.stderr)

        if downloaded:
            print(f"Converting {len(downloaded)} file(s) to webp...")
            # WebP's bitstream format hard-caps width/height at 16383px, so
            # downscale anything bigger before converting (the trailing '>'
            # means "only resize if larger than this", smaller images are
            # left untouched). Don't use check=True: one oversized/corrupt
            # input shouldn't take down the whole batch.
            result = subprocess.run(
                ["mogrify", "-resize", "16383x16383>",
                    "-format", "webp", *downloaded],
                capture_output=True,
                text=True,
            )
            if result.returncode != 0:
                print(f"  mogrify reported errors:\n{
                      result.stderr}", file=sys.stderr)

            for path in downloaded:
                webp_path = os.path.splitext(path)[0] + ".webp"
                if os.path.exists(webp_path):
                    os.remove(path)
                else:
                    print(f"  Keeping original, conversion failed: {
                          path}", file=sys.stderr)

        page += 1
        time.sleep(1)  # be polite to the API


if __name__ == "__main__":
    main()