"""photo-pipeline: Takeout download + extract flow (v2).

Completes the dump-tracking loop:
  1. Download Takeout archives (resume-capable via aria2c)
  2. Verify archive sha256 against takeout_archives (no re-download of known archives)
  3. Extract to /mnt/data/takeout/<export>/
  4. Update status in takeout_archives

Takeout gives each export a set of archive URLs (the "Download" page). Save them
to a manifest file (one URL per line) or pass a list.
"""

import shutil
import subprocess
from pathlib import Path

from prefect import flow, task

import photo_db as db

STAGING = Path("/mnt/data/takeout")


@task
def download_archive(url: str, dest_dir: Path = STAGING) -> Path:
    """Download one Takeout archive with aria2c (resume-capable, 4 connections).

    Returns the local archive path. Skips if archive sha256 already known+downloaded.
    """
    dest_dir.mkdir(parents=True, exist_ok=True)
    archive_name = url.split("/")[-1].split("?")[0]
    if not archive_name:
        archive_name = f"takeout-{abs(hash(url))}.zip"
    dest = dest_dir / archive_name

    # Skip if we already have it downloaded (by name)
    if dest.exists() and dest.stat().st_size > 0:
        print(f"  already on disk: {archive_name} ({dest.stat().st_size} bytes) — verifying sha256")
        sha = db.sha256_file(dest)
        conn = db.get_db()
        known = conn.execute(
            "SELECT id FROM takeout_archives WHERE archive_name=? AND sha256=?", (archive_name, sha)
        ).fetchone()
        conn.close()
        if known:
            print(f"  verified — already tracked (id={known[0]}). Skipping download.")
            return dest
        print(f"  on disk but untracked sha — re-downloading to be safe")

    print(f"Downloading {archive_name} → {dest}")
    cmd = [
        "aria2c",
        "-x", "4", "-s", "4",          # 4 connections
        "-c",                          # continue/resume
        "--auto-file-renaming=false",
        "--allow-overwrite=false",
        "-d", str(dest_dir),
        "-o", archive_name,
        url,
    ]
    r = subprocess.run(cmd, capture_output=True, text=True)
    if r.returncode != 0:
        raise RuntimeError(f"aria2c failed for {archive_name}:\n{r.stderr[-1000:]}")
    return dest


@task
def track_archive(archive_path: Path, export_id: str | None = None) -> int:
    """Record the downloaded archive in takeout_archives (or update it)."""
    db.init_db()
    conn = db.get_db()
    archive_id = db.register_takeout_archive(conn, archive_path.name, archive_path)
    if export_id:
        conn.execute(
            "UPDATE takeout_archives SET export_id=? WHERE id=?", (export_id, archive_id)
        )
    conn.commit()
    conn.close()
    print(f"Tracked archive id={archive_id} ({archive_path.name}, {archive_path.stat().st_size} bytes)")
    return archive_id


@task
def extract_archive(archive_path: Path, export_dir: str | None = None) -> Path:
    """Extract a Takeout archive to /mnt/data/takeout/<archive_stem>/.

    Handles .zip (unzip or python zipfile) and .tgz/.tar.gz (tar).
    """
    if export_dir:
        out_root = STAGING / export_dir
    else:
        out_root = STAGING / archive_path.stem.replace(".tar", "")
    out_root.mkdir(parents=True, exist_ok=True)

    if archive_path.suffix == ".zip" or archive_path.name.endswith(".zip"):
        # Try unzip first; fall back to python zipfile (no external dep)
        if shutil.which("unzip"):
            r = subprocess.run(
                ["unzip", "-o", "-q", str(archive_path), "-d", str(out_root)],
                capture_output=True, text=True,
            )
            if r.returncode != 0:
                raise RuntimeError(f"unzip failed: {r.stderr[-500:]}")
        else:
            import zipfile
            with zipfile.ZipFile(archive_path) as zf:
                zf.extractall(out_root)
    elif archive_path.name.endswith((".tgz", ".tar.gz", ".tar")):
        r = subprocess.run(
            ["tar", "-xzf", str(archive_path), "-C", str(out_root)],
            capture_output=True, text=True,
        )
        if r.returncode != 0:
            raise RuntimeError(f"tar failed: {r.stderr[-500:]}")
    else:
        raise ValueError(f"Unsupported archive type: {archive_path.name}")

    # Count extracted files
    n = sum(1 for _ in out_root.rglob("*") if _.is_file())
    db.init_db()
    conn = db.get_db()
    conn.execute(
        "UPDATE takeout_archives SET extracted_at=datetime('now'), extract_path=?, file_count=?, status='extracted' "
        "WHERE archive_name=?",
        (str(out_root), n, archive_path.name),
    )
    conn.commit()
    conn.close()
    print(f"Extracted {n} files → {out_root}")
    return out_root


@flow(name="takeout-fetch")
def takeout_fetch(
    urls: list[str] | None = None,
    manifest: str | None = None,
    export_id: str | None = None,
):
    """Download + track + extract a set of Takeout archives.

    Args:
        urls: list of archive download URLs (from takeout.google.com Download page)
        manifest: path to a text file with one URL per line (alternative to urls)
        export_id: label for this export (e.g. "photos-2026-08")
    """
    if manifest:
        mp = Path(manifest)
        if not mp.exists():
            raise FileNotFoundError(f"manifest not found: {mp}")
        urls = [l.strip() for l in mp.read_text().splitlines() if l.strip().startswith("http")]
    if not urls:
        raise ValueError("provide urls or a manifest file")

    results = []
    for url in urls:
        path = download_archive(url)
        archive_id = track_archive(path, export_id=export_id)
        out = extract_archive(path, export_dir=export_id)
        results.append({"archive": path.name, "id": archive_id, "extracted_to": str(out)})
    return results


if __name__ == "__main__":
    import sys
    if len(sys.argv) < 2:
        print("usage: python takeout_fetch.py <manifest-file> [export_id]")
        sys.exit(1)
    man = sys.argv[1]
    eid = sys.argv[2] if len(sys.argv) > 2 else None
    takeout_fetch(manifest=man, export_id=eid)