#!/usr/bin/env python3
"""
archival.py — Create SquashFS (optionally LUKS-encrypted) containers from
MedMan-managed files, preserving the hash-based directory hierarchy and
embedding an index.json with tag metadata per container.

The container size limit is applied BEFORE packing, meaning the sum of the
individual file sizes within a container must not exceed the limit. A small
margin is reserved for the index.json + filesystem overhead.

Workflow:
  1. Query MedMan's API (or direct DB) for files matching filters (tags,
     date range, MIME type).
  2. Group files into containers respecting the size limit (greedy bin-packing).
  3. For each container, write a temporary index.json, then stream files
     plus the index.json via tar → sqfstar directly into a SquashFS image —
     no on-disk staging directory needed (like squashr).
  4. Optionally encrypt the resulting .squashfs image with LUKS (cryptsetup).
"""

import os
import sys
import json
import argparse
import sqlite3
import shutil
import subprocess
import urllib.request
import urllib.error
from datetime import datetime, timezone
from typing import List, Tuple, Dict, Set, Optional


# ── helpers ──────────────────────────────────────────────────────────────────

def gdb(db_path: str) -> sqlite3.Connection:
    """Open MedMan database with row factory."""
    if not os.path.isfile(db_path):
        print(f"ERROR: database not found: {db_path}", file=sys.stderr)
        sys.exit(1)
    c = sqlite3.connect(db_path)
    c.row_factory = sqlite3.Row
    return c


def resolve_data_dirs(dat_specs: List[str]) -> List[str]:
    """Resolve data directory list from repeated --dat arguments."""
    return [os.path.abspath(d.strip()) for d in dat_specs if d.strip()]


def fetch_medman_export(medman_url: str, tags: Optional[List[str]]) -> dict:
    """
    Fetch the MedMan tag export JSON via the HTTP API.

    The full export includes ``tags`` (all known tags) and ``files``, a dict
    keyed by hash — each value contains ``didx``, ``rel``, and ``tags``.

    When *tags* is given, the ``?tags=a,b`` query parameter is appended so
    the server returns only matching files (AND semantics).
    """
    url = medman_url.rstrip("/")
    if not url.endswith("/api/tags/export"):
        url += "/api/tags/export"

    if tags:
        url += "?tags=" + ",".join(tags)

    print(f"  Fetching: {url}")
    try:
        with urllib.request.urlopen(url, timeout=60) as resp:
            data = json.loads(resp.read().decode("utf-8"))
    except urllib.error.URLError as exc:
        print(f"ERROR: cannot reach MedMan API at {url}: {exc}", file=sys.stderr)
        sys.exit(1)
    except json.JSONDecodeError as exc:
        print(f"ERROR: invalid JSON from MedMan API: {exc}", file=sys.stderr)
        sys.exit(1)

    return data


def resolve_files_from_export(
    export: dict,
    dat_dirs: List[str],
    hashes: Optional[Set[str]],
    mime_type: Optional[str],
    from_date: Optional[str],
    to_date: Optional[str],
) -> List[dict]:
    """
    Given a MedMan export dict and data-directory list, resolve every file
    hash to its absolute on-disk path.  Apply additional optional filters
    (hash set, MIME type, date range on mtime).

    Returns a list of dicts ready for ``split_files``.
    """
    files_info = export.get("files", {})

    # Parse date filters
    from_dt = None
    to_dt = None
    if from_date:
        try:
            from_dt = datetime.fromisoformat(from_date)
        except ValueError:
            print(f"ERROR: invalid --from-date format: {from_date}", file=sys.stderr)
            sys.exit(1)
    if to_date:
        try:
            to_dt = datetime.fromisoformat(to_date)
        except ValueError:
            print(f"ERROR: invalid --to-date format: {to_date}", file=sys.stderr)
            sys.exit(1)

    files: List[dict] = []
    for h, info in files_info.items():
        # Apply hash filter
        if hashes is not None and h not in hashes:
            continue

        didx = info.get("didx", 0)
        file_tags_list = info.get("tags", [])

        # Reconstruct rel from hash (always deterministic)
        pairs = [h[i:i+2] for i in range(0, len(h), 2)]
        rel = "/".join(pairs)

        # Resolve absolute path
        if didx >= len(dat_dirs):
            print(f"WARNING: didx {didx} out of range for hash {h[:16]}…, skipping",
                  file=sys.stderr)
            continue

        ap = os.path.join(dat_dirs[didx], rel)
        if not os.path.isfile(ap):
            print(f"WARNING: file not found on disk: {ap}", file=sys.stderr)
            continue

        # Filesystem metadata
        st = os.stat(ap)
        size = st.st_size
        mtime_ts = st.st_mtime

        # Date filter (on mtime)
        if from_dt or to_dt:
            mtime_dt = datetime.fromtimestamp(mtime_ts, tz=timezone.utc)
            if from_dt and mtime_dt < from_dt:
                continue
            if to_dt and mtime_dt > to_dt:
                continue

        # MIME type filter
        if mime_type:
            mt = _quick_mime(ap)
            if mt != mime_type and not mt.startswith(mime_type):
                continue

        files.append({
            "hash": h,
            "didx": didx,
            "rel": rel,  # internal only; not exported
            "size": size,
            "mt": _quick_mime(ap),
            "w": None,
            "h": None,
            "dur": None,
            "abspath": ap,
            "tags": file_tags_list,
        })

    return files


def _quick_mime(ap: str) -> str:
    """Quick file-type detection by extension (offline-safe)."""
    ext = os.path.splitext(ap)[1].lower()
    if ext in {".mp4", ".mkv", ".webm", ".avi", ".mov", ".m4v", ".wmv", ".flv", ".ogv"}:
        return "video"
    if ext in {".jpg", ".jpeg", ".png", ".gif", ".bmp", ".webp", ".svg", ".tiff", ".ico"}:
        return "image"
    if ext in {".mp3", ".wav", ".ogg", ".flac", ".aac", ".m4a", ".wma", ".opus"}:
        return "audio"
    if ext in {".pdf", ".epub", ".txt", ".md", ".rst"}:
        return "doc"
    return "other"


# ── DB-based query (fallback / legacy) ───────────────────────────────────────

def query_files_by_tags(
    db: sqlite3.Connection,
    dat_dirs: List[str],
    tags: Optional[List[str]],
    hashes: Optional[Set[str]],
    from_date: Optional[str] = None,
    to_date: Optional[str] = None,
    mime_type: Optional[str] = None,
) -> List[dict]:
    """
    Return files from MedMan DB with their on-disk paths.

    Supports tag, hash, date-range, and MIME-type filters.
    """
    if tags:
        names = [t.strip().lower() for t in tags if t.strip()]
    else:
        names = []

    # Parse date filters
    from_dt: Optional[datetime] = None
    to_dt: Optional[datetime] = None
    if from_date:
        try:
            from_dt = datetime.fromisoformat(from_date)
        except ValueError:
            print(f"ERROR: invalid --from-date: {from_date}", file=sys.stderr)
            sys.exit(1)
    if to_date:
        try:
            to_dt = datetime.fromisoformat(to_date)
        except ValueError:
            print(f"ERROR: invalid --to-date: {to_date}", file=sys.stderr)
            sys.exit(1)

    files: List[dict] = []

    if names:
        ph = ",".join("?" for _ in names)
        rows = db.execute(
            f"""SELECT ft.hash,f.didx,f.size,f.mt,f.w,f.h,f.dur,f.ts,
                       COUNT(DISTINCT t.id) AS mc
            FROM ftags ft
            JOIN tags t ON t.id=ft.tid
            JOIN files f ON f.hash=ft.hash
            WHERE t.name IN ({ph})
            GROUP BY ft.hash
            HAVING mc=?""",
            names + [len(names)],
        ).fetchall()
    else:
        rows = db.execute(
            "SELECT hash,didx,size,mt,w,h,dur,ts FROM files"
        ).fetchall()

    for r in rows:
        h = r["hash"]
        if hashes is not None and h not in hashes:
            continue

        rel = h2rel(h)
        ap = os.path.join(dat_dirs[r["didx"]], rel)
        if not os.path.isfile(ap):
            continue

        # Date filter on filesystem mtime
        st_mtime = os.path.getmtime(ap)
        if from_dt or to_dt:
            mtime_dt = datetime.fromtimestamp(st_mtime, tz=timezone.utc)
            if from_dt and mtime_dt < from_dt:
                continue
            if to_dt and mtime_dt > to_dt:
                continue

        # MIME type filter
        if mime_type:
            mt = r["mt"] or _quick_mime(ap)
            if mt != mime_type and not mt.startswith(mime_type):
                continue

        files.append({
            "hash": h,
            "didx": r["didx"],
            "size": r["size"] if r["size"] else os.path.getsize(ap),
            "mt": r["mt"],
            "w": r["w"],
            "h": r["h"],
            "dur": r["dur"],
            "abspath": ap,
        })
    return files


def query_all_tags(db: sqlite3.Connection) -> List[dict]:
    """Return all known tags as list of dicts."""
    return [dict(r) for r in db.execute("SELECT id, name FROM tags ORDER BY name").fetchall()]


def query_file_tags(db: sqlite3.Connection, hashes: List[str]) -> Dict[str, List[str]]:
    """Return {hash: [tag_name, ...]} for the given hashes."""
    result: Dict[str, List[str]] = {h: [] for h in hashes}
    if not hashes:
        return result
    ph = ",".join("?" for _ in hashes)
    rows = db.execute(
        f"""SELECT ft.hash,t.name FROM ftags ft
            JOIN tags t ON t.id=ft.tid
            WHERE ft.hash IN ({ph})
            ORDER BY ft.hash,t.name""",
        hashes,
    ).fetchall()
    for r in rows:
        result[r["hash"]].append(r["name"])
    return result


# ── bin-packing ──────────────────────────────────────────────────────────────

def split_files(
    files: List[dict],
    max_container_size: int,
    margin_bytes: int = 0,
) -> Dict[int, List[dict]]:
    """
    Greedy first-fit-decreasing bin packing.

    Returns {container_index: [file_dict, ...]}.

    *max_container_size* is the maximum sum of file sizes allowed per container.
    *margin_bytes* is subtracted from max_container_size internally to leave
    room for the index.json and filesystem structures.
    """
    effective_limit = max_container_size - margin_bytes
    if effective_limit <= 0:
        print("ERROR: container size too small after margin", file=sys.stderr)
        sys.exit(1)

    # Sort descending by size for best-fit-decreasing
    files_sorted = sorted(files, key=lambda f: f["size"], reverse=True)

    containers: Dict[int, List[dict]] = {}
    container_sizes: Dict[int, int] = {}
    container_index = 0

    for f in files_sorted:
        fsize = f["size"]

        if fsize > effective_limit:
            print(
                f"WARNING: file too large for container "
                f"({fsize} > {effective_limit}): {f['abspath']}",
                file=sys.stderr,
            )
            continue

        # Find first existing container where this file fits
        placed = False
        for ci in sorted(containers.keys()):
            if container_sizes[ci] + fsize <= effective_limit:
                containers[ci].append(f)
                container_sizes[ci] += fsize
                placed = True
                break

        if not placed:
            containers[container_index] = [f]
            container_sizes[container_index] = fsize
            container_index += 1

    return containers


# ── index.json ───────────────────────────────────────────────────────────────

def build_index_json(
    files: List[dict],
    file_tags: Dict[str, List[str]],
    all_tags: List[dict],
) -> str:
    """Build the index.json content in MedMan export format.  No ``rel`` — canonical from hash."""
    ft: Dict[str, dict] = {}
    for f in files:
        h = f["hash"]
        entry: dict = {"didx": f["didx"]}
        # Use tags from file dict if present (API path), else from DB lookup
        if "tags" in f and f["tags"]:
            entry["tags"] = f["tags"]
        else:
            entry["tags"] = file_tags.get(h, [])
        ft[h] = entry

    export = {
        "ts": datetime.now(timezone.utc).isoformat(),
        "tags": all_tags,
        "files": ft,
    }
    return json.dumps(export, indent=2)


# ── piped tar → sqfstar (like squashr's build_squash_image_tar_sqfstar) ──────

def _find_tool(name: str) -> Optional[str]:
    """Find a tool in PATH, returning its path or None."""
    return shutil.which(name)


def build_squashfs_piped(
    container_files: List[dict],
    index_json_str: str,
    output_file: str,
    mksquashfs_args: str,
) -> bool:
    """
    Build a SquashFS image for *container_files* with *index_json_str* at
    the root — without any on-disk staging directory.

    Strategy:
      1. Write index.json to a temporary file alongside the output.
      2. Build file list for tar: null-delimited entries for the index.json
         (with --transform to place it at root) and every file to include.
      3. Pipe: tar (reading file list) → sqfstar, which creates the
         SquashFS image directly (identical approach to squashr).
    """
    sqfstar_bin = _find_tool("sqfstar")
    if not sqfstar_bin:
        print("ERROR: sqfstar not found in PATH (required for staging-free builds).",
              file=sys.stderr)
        return False

    # Write index.json to a temporary file next to the output so tar can
    # include it with --transform to place it at the archive root.
    idx_tmp = output_file + ".tmp-index-" + str(os.getpid())
    try:
        with open(idx_tmp, "w", encoding="utf-8") as fh:
            fh.write(index_json_str)

        # Build the tar input: first the index.json temporary file, then
        # all file paths.  We use the same approach as squashr:
        # tar --null --files-from=- with / as root.
        paths_for_tar: List[str] = []
        paths_for_tar.append(idx_tmp)
        for fi in container_files:
            paths_for_tar.append(fi["abspath"])

        return _run_tar_sqfstar(paths_for_tar, output_file,
                                mksquashfs_args, sqfstar_bin, idx_tmp)
    finally:
        # Clean up the temporary index.json file
        try:
            os.unlink(idx_tmp)
        except OSError:
            pass


def _run_tar_sqfstar(
    paths: List[str],
    output_file: str,
    squashfs_args: str,
    sqfstar_bin: str,
    idx_tmp_path: str,
) -> bool:
    """
    Pipe: tar (reading a null-delimited file list from stdin) → sqfstar.

    The first path in *paths* is the temporary index.json file; a
    --transform rule places it at the root of the archive as index.json.

    tar options:
      --null --files-from=-  → read null-delimited paths from stdin
      -C /                   → resolve paths from filesystem root
      --format=posix
      -cf -                  → write tar stream to stdout
      --numeric-owner
      --ignore-failed-read
      --transform …          → place the temporary index.json as /index.json

    sqfstar options:
      -comp <algo> ...       → from *squashfs_args*
      <output_file> -        → read tar from stdin
    """
    tar_args = [
        "tar",
        "--null",
        "--files-from=-",
        "-C", "/",
        "--format=posix",
        "-cf", "-",
        "--numeric-owner",
        "--ignore-failed-read",
        f"--transform=flags=r;s|^{idx_tmp_path.lstrip('/')}$|index.json|",
    ]

    sqfstar_args = [sqfstar_bin]
    if squashfs_args:
        sqfstar_args.extend(squashfs_args.split())
    sqfstar_args.append(output_file)
    sqfstar_args.append("-")  # read from stdin

    print(f"  Pipe: tar → sqfstar → {output_file}")

    try:
        sqfstar_proc = subprocess.Popen(
            sqfstar_args,
            stdin=subprocess.PIPE,
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE,
            text=False,
        )

        tar_proc = subprocess.Popen(
            tar_args,
            stdin=subprocess.PIPE,
            stdout=sqfstar_proc.stdin,
            stderr=subprocess.PIPE,
            text=False,
        )

        # Close sqfstar's stdin in this process (tar writes to it)
        if sqfstar_proc.stdin:
            sqfstar_proc.stdin.close()

        # Write the null-delimited file list into tar's stdin
        for p in paths:
            tar_proc.stdin.write(p.encode("utf-8"))
            tar_proc.stdin.write(b"\0")
        tar_proc.stdin.close()

        # Wait for both
        tar_rc = tar_proc.wait()
        sq_rc = sqfstar_proc.wait()

        if tar_rc != 0:
            stderr_data = tar_proc.stderr.read().decode("utf-8", errors="replace")
            print(f"WARNING: tar exited with code {tar_rc}", file=sys.stderr)
            if stderr_data:
                print(f"  tar stderr: {stderr_data[:500]}", file=sys.stderr)

        if sq_rc != 0:
            stderr_data = sqfstar_proc.stderr.read().decode("utf-8", errors="replace")
            print(f"ERROR: sqfstar failed with code {sq_rc}", file=sys.stderr)
            if stderr_data:
                print(f"  sqfstar stderr: {stderr_data[:500]}", file=sys.stderr)
            return False

        return True

    except FileNotFoundError as exc:
        print(f"ERROR: required tool not found: {exc}", file=sys.stderr)
        return False
    except Exception as exc:
        print(f"ERROR: tar → sqfstar pipe failed: {exc}", file=sys.stderr)
        return False


# ── LUKS encryption ──────────────────────────────────────────────────────────

def encrypt_container(
    output_file: str,
    cryptsetup_args: str,
    key_file: Optional[str] = None,
) -> bool:
    """
    Encrypt a SquashFS image with LUKS2 using cryptsetup reencrypt.

    Approach:
      1. Grow the image by 32 MiB to make room for the LUKS header.
      2. Run `cryptsetup reencrypt --encrypt --type luks2 --reduce-device-size 32M`.
      3. Trim 16 MiB from the image (leaving 16 MiB for LUKS header).
      4. Rename output_file → output_file.luks.
    """
    print(f"  Encrypting {output_file} …")

    # Step 1: grow
    result = subprocess.run(
        ["truncate", "-s", "+32M", output_file], capture_output=True, text=True
    )
    if result.returncode != 0:
        print("ERROR: truncate (grow) failed", file=sys.stderr)
        return False

    # Step 2: LUKS encrypt in-place
    cmd = [
        "cryptsetup", "-q", "reencrypt", "--encrypt",
        "--type", "luks2", "--reduce-device-size", "32M",
    ]
    if key_file:
        cmd.extend(["--key-file", key_file])
    if cryptsetup_args:
        cmd.extend(cryptsetup_args.split())
    cmd.append(output_file)

    result = subprocess.run(cmd, capture_output=True, text=True)
    if result.returncode != 0:
        print("ERROR: cryptsetup reencrypt failed", file=sys.stderr)
        print(f"  stderr: {result.stderr[:500]}", file=sys.stderr)
        return False

    # Step 3: trim
    result = subprocess.run(
        ["truncate", "-s", "-16M", output_file], capture_output=True, text=True
    )
    if result.returncode != 0:
        print("ERROR: truncate (trim) failed", file=sys.stderr)
        return False

    # Step 4: rename to .luks
    luks_file = f"{output_file}.luks"
    os.rename(output_file, luks_file)
    print(f"  Encrypted container: {luks_file}")
    return True


# ── statistics ───────────────────────────────────────────────────────────────

def print_statistics(containers: Dict[int, List[dict]], max_size: int) -> None:
    total_files = 0
    total_size = 0

    print("\n--- Stats ---")
    for ci in sorted(containers.keys()):
        files = containers[ci]
        csize = sum(f["size"] for f in files)
        util = (csize / max_size * 100) if max_size > 0 else 0
        print(f"Container {ci}:")
        print(f"  Files:     {len(files)}")
        print(f"  Size:      {csize:,} bytes ({csize / 1024**2:.2f} MiB)")
        print(f"  Utilization: {util:.1f} %")
        total_files += len(files)
        total_size += csize

    print(f"\nTotal: {total_files} files, {total_size:,} bytes "
          f"({total_size / 1024**2:.2f} MiB)")
    if containers:
        avg = total_size / (len(containers) * max_size) * 100 if max_size > 0 else 0
        print(f"Avg. container utilization: {avg:.1f} %")


# ── main ─────────────────────────────────────────────────────────────────────

def main():
    parser = argparse.ArgumentParser(
        description="Create SquashFS (optionally LUKS) containers from MedMan-managed files."
    )

    # ── MedMan data source (mutually exclusive: API or direct DB) ────────
    src_group = parser.add_mutually_exclusive_group(required=True)
    src_group.add_argument(
        "--medman-url",
        help="Base URL of a running MedMan instance (e.g. http://localhost:8080). "
             "Uses the HTTP API to fetch file/tag data.",
    )
    src_group.add_argument(
        "--db",
        help="Path to MedMan SQLite database (medman.db) – direct access.",
    )

    parser.add_argument(
        "--dat", "--data-dir",
        action="append",
        default=[],
        help="MedMan data directory (can be repeated).",
    )

    # ── File selection ────────────────────────────────────────────────────
    parser.add_argument(
        "--tags",
        nargs="*",
        default=[],
        help="Only include files with ALL of these tags (AND).",
    )
    parser.add_argument(
        "--hashes",
        nargs="*",
        default=[],
        help="Only include files with these hashes (space-separated).",
    )
    parser.add_argument(
        "--hashes-from-file",
        help="Read hashes from file (one per line).",
    )
    parser.add_argument(
        "--from-date",
        help="Only include files modified on or after this date (ISO format, e.g. 2024-01-01).",
    )
    parser.add_argument(
        "--to-date",
        help="Only include files modified on or before this date (ISO format).",
    )
    parser.add_argument(
        "--mime-type",
        help="Only include files of this media type (video, image, audio, doc, other).",
    )

    # ── Container sizing ──────────────────────────────────────────────────
    parser.add_argument(
        "--container-size",
        "-c",
        type=int,
        required=True,
        help="Maximum container size in bytes (sum of file sizes, pre-packing).",
    )
    parser.add_argument(
        "--margin",
        type=int,
        default=1_048_576,  # 1 MiB
        help="Margin in bytes reserved for index.json + FS metadata (default: 1 MiB).",
    )

    # ── Output ────────────────────────────────────────────────────────────
    parser.add_argument(
        "--output-prefix",
        "-o",
        required=True,
        help="Prefix for output container files.",
    )

    # ── mksquashfs / sqfstar ──────────────────────────────────────────────
    parser.add_argument(
        "--mksquashfs-args",
        default="-comp xz -b 1M",
        help="Additional arguments passed to mksquashfs or sqfstar "
             "(default: '-comp xz -b 1M').",
    )

    # ── cryptsetup / LUKS ─────────────────────────────────────────────────
    parser.add_argument(
        "--cryptsetup",
        "-e",
        action="store_true",
        help="Encrypt each container with LUKS2 after building.",
    )
    parser.add_argument(
        "--cryptsetup-args",
        default="",
        help="Additional arguments passed to 'cryptsetup reencrypt'.",
    )
    parser.add_argument(
        "--key-file",
        help="Path to a key file for LUKS encryption (passed to cryptsetup).",
    )

    # ── misc ──────────────────────────────────────────────────────────────
    parser.add_argument(
        "--verbose",
        "-v",
        action="store_true",
        help="Print detailed statistics.",
    )

    args = parser.parse_args()

    # ── prerequisites ─────────────────────────────────────────────────────
    if not shutil.which("tar"):
        print("ERROR: tar not found in PATH.", file=sys.stderr)
        sys.exit(1)
    if args.cryptsetup and not shutil.which("cryptsetup"):
        print("ERROR: cryptsetup not found in PATH.", file=sys.stderr)
        sys.exit(1)

    if shutil.which("sqfstar") is None:
        print("ERROR: sqfstar (squashfs-tools-ng) not found in PATH.", file=sys.stderr)
        sys.exit(1)

    print("Using sqfstar for direct tar→squashfs streaming (no staging).")

    # ── resolve hashes ────────────────────────────────────────────────────
    hashes: Optional[Set[str]] = None
    if args.hashes or args.hashes_from_file:
        hashes = set(args.hashes or [])
        if args.hashes_from_file:
            with open(args.hashes_from_file, "r", encoding="utf-8") as fh:
                for line in fh:
                    line = line.strip()
                    if line and not line.startswith("#"):
                        hashes.add(line)

    if not args.dat:
        print("ERROR: at least one --dat is required.", file=sys.stderr)
        sys.exit(1)

    dat_dirs = resolve_data_dirs(args.dat)
    tags_filter = args.tags if args.tags else None

    # ── query MedMan (API or DB) ──────────────────────────────────────────
    all_tags: List[dict] = []
    file_tags: Dict[str, List[str]] = {}
    files: List[dict] = []

    if args.medman_url:
        # ── API path ──────────────────────────────────────────────────────
        export = fetch_medman_export(args.medman_url, tags_filter)
        all_tags = export.get("tags", [])

        files = resolve_files_from_export(
            export, dat_dirs, hashes,
            args.mime_type, args.from_date, args.to_date,
        )

        # Tags are already embedded in each file dict from the export
        for f in files:
            file_tags[f["hash"]] = f.get("tags", [])

    else:
        # ── Direct DB path ────────────────────────────────────────────────
        db = gdb(args.db)
        try:
            files = query_files_by_tags(
                db, dat_dirs, tags_filter, hashes,
                args.from_date, args.to_date, args.mime_type,
            )
            all_tags = query_all_tags(db)

            all_f_hashes = [f["hash"] for f in files]
            file_tags = query_file_tags(db, all_f_hashes)
        finally:
            db.close()

    if not files:
        print("No files matched the selection criteria.", file=sys.stderr)
        sys.exit(1)

    total_bytes = sum(f["size"] for f in files)
    print(f"Selected {len(files)} files, total {total_bytes:,} bytes "
          f"({total_bytes / 1024**2:.2f} MiB)")

    # ── split into containers ─────────────────────────────────────────────
    containers = split_files(files, args.container_size, args.margin)

    if not containers:
        print("No files could be packed (all too large?).", file=sys.stderr)
        sys.exit(1)

    print(f"Split into {len(containers)} container(s).")

    # ── build each container ──────────────────────────────────────────────
    for ci in sorted(containers.keys()):
        c_files = containers[ci]
        c_size = sum(f["size"] for f in c_files)
        print(f"\n── Container {ci} ──")
        print(f"   Files: {len(c_files)}, {c_size:,} bytes "
              f"({c_size / 1024**2:.2f} MiB)")

        # Build index.json for this container
        index_json_str = build_index_json(c_files, file_tags, all_tags)

        # Build squashfs
        squashfs_file = f"{args.output_prefix}-{ci}.squashfs"
        ok = build_squashfs_piped(
            c_files, index_json_str, squashfs_file, args.mksquashfs_args
        )

        if not ok:
            print(f"ERROR: failed to create {squashfs_file}", file=sys.stderr)
            sys.exit(1)

        print(f"  Created {squashfs_file}")

        # Optional LUKS encryption
        if args.cryptsetup:
            if not encrypt_container(squashfs_file, args.cryptsetup_args,
                                     args.key_file):
                sys.exit(1)

    if args.verbose:
        print_statistics(containers, args.container_size - args.margin)

    print(f"\nDone. Created {len(containers)} container(s).")


if __name__ == "__main__":
    main()