"""Library-issue detection (non-canonical filenames) + safe renaming.

Scans the cache (not the live remote) for files whose names violate
the canonical `{ID}[ - actress][ [resolution]].ext` shape:

- Bracket-wrapped IDs:  `[REAL-779].mp4`           -> `REAL-779.mp4`
- No-hyphen IDs:        `MVSD312 [576p].avi`       -> `MVSD-312 [576p].avi`

`rename_file_in_remote` performs the rclone moveto and patches the
cache in place. `rename_files_batch` writes the cache once after a
batch of renames.
"""
from __future__ import annotations

import subprocess
from pathlib import Path

from rcjav.cache import save_cache
from rcjav.ids import (
    _BRACKET_ID_RE,
    _NOHYPHEN_ID_RE,
    COMPOUND_ID_RE,
    FALLBACK_ID_RE,
    PRIMARY_ID_RE,
    extract_id,
)


def _human_size(n: int) -> str:
    nf = float(max(0, n))
    for unit in ("B", "KiB", "MiB", "GiB", "TiB"):
        if nf < 1024:
            return f"{int(nf)} B" if unit == "B" else f"{nf:.2f} {unit}"
        nf /= 1024
    return f"{nf:.2f} PiB"


def _bracket_to_canonical(filename: str) -> str:
    """[REAL-779].mp4 -> REAL-779.mp4  |  [HODV-21076] Saki [1080p].mkv -> HODV-21076 Saki [1080p].mkv"""
    stem = Path(filename).stem
    suffix = Path(filename).suffix
    bm = _BRACKET_ID_RE.match(stem)
    if not bm:
        return filename
    inner = bm.group(1).strip()
    rest = stem[bm.end():].strip()
    new_stem = f"{inner} {rest}".strip() if rest else inner
    return f"{new_stem}{suffix}"


def _nohyphen_to_canonical(filename: str) -> str:
    """MVSD312 [576p].avi -> MVSD-312 [576p].avi"""
    stem = Path(filename).stem
    suffix = Path(filename).suffix
    m = _NOHYPHEN_ID_RE.match(stem)
    if not m:
        return filename
    prefix = m.group(1).upper()
    num_str = m.group(2)
    rest = stem[m.end():]
    return f"{prefix}-{num_str}{rest}{suffix}"


def find_library_issues(cache: dict) -> dict:
    """Scan cache for files with non-canonical names.

    Returns:
        {"bracket_names": [...], "nohyphen_names": [...]}
    Each entry: {remote, path, size, mod_time, jav_id, canonical_name, issue}
    """
    bracket: list[dict] = []
    nohyphen: list[dict] = []
    for remote, remote_data in cache.get("remotes", {}).items():
        for f in remote_data.get("files", []):
            fname = Path(f["path"]).name
            stem = Path(fname).stem
            if stem.startswith("[") and _BRACKET_ID_RE.match(stem):
                bracket.append({
                    "remote": remote,
                    "path": f["path"],
                    "size": f.get("size", 0),
                    "size_human": _human_size(f.get("size", 0)),
                    "mod_time": f.get("mod_time", ""),
                    "jav_id": f.get("jav_id", ""),
                    "canonical_name": _bracket_to_canonical(fname),
                    "issue": "bracket_id",
                })
            elif (not PRIMARY_ID_RE.match(stem)
                  and not COMPOUND_ID_RE.match(stem)
                  and not FALLBACK_ID_RE.match(stem)
                  and _NOHYPHEN_ID_RE.match(stem)):
                nohyphen.append({
                    "remote": remote,
                    "path": f["path"],
                    "size": f.get("size", 0),
                    "size_human": _human_size(f.get("size", 0)),
                    "mod_time": f.get("mod_time", ""),
                    "jav_id": f.get("jav_id", ""),
                    "canonical_name": _nohyphen_to_canonical(fname),
                    "issue": "nohyphen_id",
                })
    return {"bracket_names": bracket, "nohyphen_names": nohyphen}


def rename_file_in_remote(
    remote: str,
    old_rel_path: str,
    new_rel_path: str,
    cache: dict,
    rclone_bin: str = "rclone",
    save: bool = True,
) -> dict:
    """Rename one file via rclone moveto and patch cache.json.

    Returns {"ok": True, "old_path": ..., "new_path": ...}
         or {"ok": False, "error": ..., "conflict": bool}

    Pass save=False when batching — caller is responsible for calling save_cache() once.
    """
    sep = "" if remote.endswith("/") else "/"
    old_full = f"{remote}{sep}{old_rel_path}"
    new_full = f"{remote}{sep}{new_rel_path}"

    check = subprocess.run(
        [rclone_bin, "lsf", new_full],
        capture_output=True, text=True,
    )
    if check.returncode == 0 and check.stdout.strip():
        return {"ok": False, "error": f"Target already exists: {new_full}", "conflict": True}

    result = subprocess.run(
        [rclone_bin, "moveto", old_full, new_full],
        capture_output=True, text=True,
    )
    if result.returncode != 0:
        return {"ok": False, "error": (result.stderr or result.stdout).strip(), "conflict": False}

    remote_data = cache.get("remotes", {}).get(remote)
    if remote_data:
        for f in remote_data.get("files", []):
            if f["path"] == old_rel_path:
                f["path"] = new_rel_path
                f["jav_id"] = extract_id(Path(new_rel_path).name) or f["jav_id"]
                break
        remote_data["skipped"] = [s for s in remote_data.get("skipped", []) if s != old_rel_path]
        if save:
            save_cache(cache)

    return {"ok": True, "old_path": old_full, "new_path": new_full}


def rename_files_batch(
    renames: list[dict],
    cache: dict,
    rclone_bin: str = "rclone",
) -> list[dict]:
    """Rename multiple files, writing cache once at the end.

    Each item in renames: {remote, old_path, new_path}
    Returns list of per-file results with old_path/new_path echoed back.
    """
    results = []
    cache_dirty = False
    for r in renames:
        res = rename_file_in_remote(
            r["remote"], r["old_path"], r["new_path"],
            cache, rclone_bin=rclone_bin, save=False,
        )
        res["old_path"] = r["old_path"]
        res["new_path"] = r["new_path"]
        results.append(res)
        if res["ok"]:
            cache_dirty = True
    if cache_dirty:
        save_cache(cache)
    return results