"""Local file ingest for the download center — the non-yt-dlp path into the media library.

A user-uploaded file joins the SAME library as a downloaded one, so it inherits the whole function
set already built (metadata chips, share links, and — for media — in-app play/edit). Unlike a
download it bypasses yt-dlp: the file is already on the host, so ingest probes it and places it on
disk. A file that already is the phone-safe shape (`playable`) — or is not media at all — becomes an
already-`ready` MediaAsset + `done` DownloadJob in one step, the same "the file exists, mark it done
now" shortcut `service.enqueue` takes on a cache hit.

Media that is NOT phone-safe (an iPhone's HEVC .mov, a VP9 .webm, an .mkv) is placed as it came and
queued: the asset stays `pending` and the job `queued`, and the download worker converts it
(`pipeline._convert_upload`) — so a share link never hands a friend a file their phone cannot play.
Only the converted file is kept (the owner's choice: one file per upload). A 10-bit HDR original
becomes 8-bit H.264 with its colour tags kept — still tagged HDR (HLG/PQ, BT.2020), not tone-mapped
to SDR (the owner's choice too). Until then the original sits at the asset's `rel_path`, which is
what a failed conversion's Retry starts from again, and what a delete removes
(`service.release_asset`).

Kinds (the invariant lives in `mediakind`): a probe with a real video stream -> video, audio-only
-> audio, neither -> a generic 'file' (pdf/zip/docx/…) that is download-only and never rendered
inline (see the force-download serving in the file/watch routes).

An upload does NOT get an `expires_at`: it's user-provided and may be irreplaceable (there's no
source to re-download), so it doesn't age out on the retention clock the way a re-fetchable download
does — it lives until the user deletes it.
"""

import secrets
from datetime import datetime, timezone
from pathlib import Path

from sqlalchemy.orm import Session

from app.config import settings
from app.downloads import edit as editmod
from app.downloads import folders, mediakind, playable, probe, quota, service, storage
from app.downloads.status import JobKind, JobStatus
from app.models import DownloadJob, MediaAsset, display_text


def _title_from_filename(filename: str) -> str:
    """A human display title from the original upload name: the stem with separators tidied to
    spaces (kept as-is otherwise — this is display metadata, not the shell-safe on-disk name)."""
    stem = Path(filename).stem.replace("_", " ").replace(".", " ").strip()
    return (stem or "Upload")[:255]


def ingest_upload(
    db: Session,
    user_id: int,
    *,
    filename: str,
    src_path: Path,
    size: int,
    display_name: str | None = None,
) -> DownloadJob:
    """Ingest an already-uploaded file at `src_path` into `user_id`'s library and return its job —
    `done`, or `queued` for the worker's phone-safe conversion (see the module docstring). `src_path`
    is MOVED into place on success (the caller stages it to a temp file first).

    Raises quota.QuotaExceeded (holdings/footprint cap) — checked BEFORE any disk write, so a
    rejected upload leaves nothing behind and the caller just cleans up its temp file."""
    quota.check_upload(db, user_id, size)  # the file's size is known → charge it up front

    data = probe.probe_json(src_path)
    vcodec, acodec, width, height, duration = probe.facts(data)
    kind = mediakind.derive(vcodec, acodec)
    # Judged by the extension the file is PLACED under (and the worker re-judges), not the raw one:
    # 'clip.mp4~' is stored as .mp4, and judging 'mp4~' queued a conversion with nothing to convert.
    ext = storage.upload_ext(filename) or ""
    safe = playable.plan(data, ext) if kind != mediakind.FILE else None
    convert = safe is not None and safe.needs_change

    # An upload never dedups (each file is its own asset): a random ref makes the cache key unique,
    # so `format_sig` is a constant marker rather than a format hash.
    ref = f"{user_id}:{secrets.token_hex(8)}"[:512]
    asset = MediaAsset(
        source_kind="upload", source_ref=ref, format_sig="upload", status="pending", ref_count=0
    )
    db.add(asset)
    db.flush()  # need asset.id for the on-disk path

    rel = storage.upload_rel_path(user_id, asset.id, filename)
    storage.place_file(src_path, settings.files_root, rel)
    # From here the file is on disk under `.uploads/`. If the transaction fails before it commits, the
    # asset/job rows roll back and nothing names the placed file: the per-user delete path keys off
    # asset.rel_path (which is gone), and the GC's `.uploads` sweep reaches it only an hour later. So
    # roll back the on-disk side too — unless the commit itself raised after it landed (see below).
    asset_id = asset.id
    try:
        final = storage.abs_path(settings.files_root, rel)
        actual_size = final.stat().st_size if final.exists() else size

        asset.status = "pending" if convert else "ready"
        asset.rel_path = rel
        asset.size_bytes = actual_size
        asset.container = ext or None
        asset.vcodec = vcodec
        asset.acodec = acodec
        asset.width = width
        asset.height = height
        asset.duration_s = duration
        asset.media_kind = kind
        asset.title = (display_name or "").strip() or _title_from_filename(filename)
        asset.last_access_at = datetime.now(timezone.utc)
        # No expires_at — see the module docstring (an upload is irreplaceable, so it doesn't age out).
        if kind == mediakind.VIDEO:
            # A frame poster gives the library row a thumbnail + the share link an og:image. Audio has
            # no frame and a generic file no player, so neither gets one. Best-effort (ffmpeg decodes
            # server side even for a codec the browser can't play).
            asset.poster_path = editmod.ensure_poster(asset, settings.files_root)

        job = DownloadJob(
            user_id=user_id,
            asset_id=asset.id,
            job_kind=JobKind.UPLOAD,
            source_kind="upload",
            source_ref=ref,
            profile_snapshot={},
            display_name=display_text(display_name),
            status=JobStatus.QUEUED if convert else JobStatus.DONE,
            progress=0 if convert else 100,
            queue_pos=service.next_queue_pos(db),
        )
        db.add(job)
        folders.place(db, job)
        if not convert:
            folders.stamp_expiry(db, job)
        service.incr_ref_count(db, asset.id)
        db.commit()
    except Exception:
        db.rollback()
        if _row_landed(db, asset_id) is not False:
            # The commit reached the server and lost its answer, or the row cannot be read: the file
            # may be the asset's now, so it is never removed blind — the sweep takes it if no row
            # names it.
            raise
        # The rows are gone; remove the now-unreferenced file so no bytes leak. Clean the poster by its
        # DETERMINISTIC path (rel with a .jpg suffix, the same path ensure_poster writes to) rather than
        # ensure_poster's return value: it writes the frame directly to that path and returns None on an
        # ffmpeg failure, so a partial poster can be on disk while the return is None — gating on the
        # return would skip that orphan. unlink is missing_ok, so the poster path is a harmless no-op
        # when none was generated (audio/file, or a video whose poster never started).
        for leaked in (rel, str(Path(rel).with_suffix(".jpg"))):
            storage.abs_path(settings.files_root, leaked).unlink(missing_ok=True)
        raise
    db.refresh(job)
    return job


def _row_landed(db: Session, asset_id: int) -> bool | None:
    """After the ingest transaction raised: is the asset row there anyway? A commit can reach the
    server and lose its answer (the connection drops after COMMIT). None when it cannot be read."""
    try:
        return db.get(MediaAsset, asset_id) is not None
    except Exception:  # noqa: BLE001 — "cannot tell" is the answer, the caller acts on it
        # silent-ok: the caller re-raises the ingest's own error.
        return None