"""Sorter: place collection files into the library via plan/apply.

See docs/SORTING.md for the structure and the pipeline this implements:
inspect (name + archive listing) -> classify (keyword tables) -> fuzzy match
against the library catalog -> plan -> apply (hardlink, fallback copy).

The sorter never deletes or modifies source files. Applying is append-only:
targets that already exist are skipped, actions are audited in
sorter_applied.jsonl.
"""

from __future__ import annotations

import difflib
import json
import logging
import os
import shutil
import subprocess
import zipfile
from dataclasses import dataclass, field
from pathlib import Path

from dlphelper.catalogue import _clean_name, _match_class, _match_faction
from dlphelper.warhammer_data import GROUP_OF_FACTION

log = logging.getLogger(__name__)

ARCHIVE_SUFFIXES = {".zip", ".7z", ".rar", ".tar", ".gz"}
UNSORTED = "_unsorted"
UNCLASSIFIED_CLASS = "Unclassified"

# Run-artifact files that must never be sorted into a library
RUN_ARTIFACTS = {
    "export.json", "export.html", "state.json", "manifest.jsonl",
    "failed_urls.txt", "catalogue.md", "catalogue.jsonl",
    "sorter_applied.jsonl", "catalogue_moves.jsonl", "urls.txt",
}


@dataclass
class SortItem:
    """One file to sort, plus everything learned about it."""

    path: Path
    size: int
    name: str            # original file name
    clean: str           # cleaned lower-case name
    inner_names: list[str] = field(default_factory=list)  # archive listing
    system: str = "Unknown"
    group: str = UNSORTED
    faction: str = UNSORTED
    subfaction: str | None = None
    klass: str | None = None
    unit: str | None = None          # canonical catalog name, if matched
    match_score: float = 0.0
    match_kind: str = "none"         # catalog | implicit | unclassified
    action: str = "link"             # link | copy
    target: Path | None = None


# ---------------------------------------------------------------------------
# inspection
# ---------------------------------------------------------------------------

def list_zip(path: Path, limit: int = 40) -> list[str]:
    """Inner names of a .zip without extracting."""
    try:
        with zipfile.ZipFile(path) as zf:
            return zf.namelist()[:limit]
    except (zipfile.BadZipFile, OSError, RuntimeError) as exc:
        log.debug("zip listing failed for %s: %s", path.name, exc)
        return []


def list_7z(path: Path, limit: int = 40) -> list[str]:
    """Inner names of a .7z via the installed 7z binary, without extracting."""
    if not shutil.which("7z"):
        return []
    try:
        proc = subprocess.run(
            ["7z", "l", "-ba", "-slt", str(path)],
            stdout=subprocess.PIPE, stderr=subprocess.DEVNULL, text=True, timeout=120,
        )
    except (OSError, subprocess.TimeoutExpired) as exc:
        log.debug("7z listing failed for %s: %s", path.name, exc)
        return []
    names: list[str] = []
    for block in proc.stdout.split("Path = ")[1:]:
        name = block.splitlines()[0].strip() if block.splitlines() else ""
        # -slt lists directories too; skip entries ending in /
        if name and not name.endswith("/"):
            names.append(name)
        if len(names) >= limit:
            break
    return names


def inspect(path: Path) -> SortItem:
    size = path.stat().st_size if path.exists() else 0
    item = SortItem(path=path, size=size, name=path.name, clean=_clean_name(path.name))
    if not path.is_file():
        return item
    if path.suffix.lower() in ARCHIVE_SUFFIXES:
        # An archive that is not an archive is almost always a saved HTML
        # error/login page that got downloaded instead of the file.
        if path.suffix.lower() == ".zip":
            item.inner_names = list_zip(path)
        else:
            item.inner_names = list_7z(path)
        if item.inner_names == [] and path.stat().st_size > 0:
            head = b""
            with path.open("rb") as fh:
                head = fh.read(512)
            if b"<!doctype html" in head.lower() or b"<html" in head.lower():
                log.warning("%s is an HTML page, not an archive (bad download)", path.name)
                item.match_kind = "invalid"
    return item


# ---------------------------------------------------------------------------
# classification & matching
# ---------------------------------------------------------------------------

def classify_item(item: SortItem) -> None:
    """Keyword classification from the file name, then refined by inner names."""
    hit = _match_faction(item.clean)
    if hit:
        item.system, item.faction = hit
    item.klass = _match_class(item.clean) or (
        _match_class(_clean_name(" ".join(item.inner_names))) if item.inner_names else None
    )

    if item.faction == UNSORTED and item.inner_names:
        # hash-named archives: vote on the inner names' classification
        votes: dict[tuple[str, str], int] = {}
        for inner in item.inner_names:
            ihit = _match_faction(_clean_name(inner))
            if ihit:
                votes[ihit] = votes.get(ihit, 0) + 1
        if votes:
            best = max(votes.items(), key=lambda kv: kv[1])[0]
            item.system, item.faction = best
            if item.klass is None:
                inner_classes = [
                    _match_class(_clean_name(inner)) for inner in item.inner_names
                ]
                cvotes: dict[str, int] = {}
                for c in inner_classes:
                    if c:
                        cvotes[c] = cvotes.get(c, 0) + 1
                if cvotes:
                    item.klass = max(cvotes.items(), key=lambda kv: kv[1])[0]

    item.group = GROUP_OF_FACTION.get(item.faction, UNSORTED)


# faction group layer (GW naming, shared with warhammer_data)


def load_catalog(path: Path) -> list[dict]:
    data = json.loads(path.read_text(encoding="utf-8"))
    entries = data["entries"] if isinstance(data, dict) else data
    for e in entries:
        e["_clean"] = _clean_name(e["name"])
        e["_clean_aliases"] = [_clean_name(a) for a in e.get("aliases", [])]
    return entries


def _best_ratio(clean: str, candidates: list[str]) -> float:
    return max(
        (difflib.SequenceMatcher(None, clean, c).ratio() for c in candidates),
        default=0.0,
    )


def _best_in_pool(item: SortItem, pool: list[dict]) -> tuple[float, dict] | None:
    """Best fuzzy score of `item` against all entries in `pool`."""
    best: tuple[float, dict] | None = None
    for entry in pool:
        cands = [entry["_clean"], *entry["_clean_aliases"]]
        score = _best_ratio(item.clean, cands)
        if item.inner_names:
            inner_clean = [_clean_name(n) for n in item.inner_names[:10]]
            for c in inner_clean:
                score = max(score, _best_ratio(c, cands) * 0.95)  # inner slightly discounted
        if best is None or score > best[0]:
            best = (score, entry)
    return best


def match_catalog(item: SortItem, catalog: list[dict], threshold: float) -> None:
    """Fuzzy-match against catalog entries in the same faction (or all).

    The matched entry is hierarchy-authoritative: group, subfaction and
    class come from the catalog (GW shop categories), and when the keyword
    classification had no faction the entry's system/faction is adopted too.
    """
    if item.faction == UNSORTED and not item.inner_names and not item.clean:
        return
    if item.match_kind == "invalid":
        return  # HTML-page masquerading as an archive; never fuzzy-match it
    same_faction = [e for e in catalog if e.get("faction") == item.faction]
    pool = same_faction or catalog  # fall back to whole catalog if faction unknown
    best = _best_in_pool(item, pool)
    if best is None or best[0] < threshold:
        # The keyword tables can lag behind GW's current categorization
        # (e.g. units moved between factions); if the faction pool has no
        # confident match, try the whole catalog before giving up.
        if same_faction:
            best = _best_in_pool(item, catalog)
    if best and best[0] >= threshold:
        entry = best[1]
        item.unit = entry["name"]
        if entry.get("group"):
            item.group = entry["group"]
        elif item.faction == UNSORTED:
            item.group = GROUP_OF_FACTION.get(entry["faction"], UNSORTED)
        if entry.get("subfaction"):
            item.subfaction = entry["subfaction"]
        # GW's class layer (shop category) beats the keyword guess, but do
        # not *narrow* it: "Battleline" is GW's bucket for core infantry,
        # a keyword-derived Hero/Elite is more specific for a proxy file.
        catalog_klass = entry.get("class")
        if catalog_klass and item.klass in (None, "", UNCLASSIFIED_CLASS):
            item.klass = catalog_klass
        item.match_score = best[0]
        item.match_kind = "catalog"
        # The catalog entry's faction is authoritative - but only adopt it
        # when it is a real army faction. Generic GW branches like
        # "Unit Type" or factionless entries would degrade a confident
        # keyword faction to a junk folder.
        entry_faction = entry.get("faction")
        generic_factions = {"Unit Type", "Heroes", "Warriors", "Character"}
        if item.faction == UNSORTED:
            if entry_faction and entry_faction not in generic_factions:
                item.system = entry["system"]
                item.faction = entry_faction
            if entry.get("group") and entry["group"] not in ("Unit Type",):
                item.group = entry["group"]
            else:
                item.group = GROUP_OF_FACTION.get(item.faction, UNSORTED)
        elif entry_faction and entry_faction not in generic_factions and entry_faction != item.faction:
            # GW moved this unit to another faction (or the keyword tables
            # are stale): trust the catalog.
            item.system = entry["system"]
            item.faction = entry_faction
            if entry.get("group") and entry["group"] != "Unit Type":
                item.group = entry["group"]
            else:
                item.group = GROUP_OF_FACTION.get(entry_faction, UNSORTED)
        elif entry.get("group") and entry["group"] not in ("Unit Type",):
            item.group = entry["group"]
    else:
        if item.faction == UNSORTED:
            item.unit = item.name  # implicit entry: own (original) name
            item.match_score = best[0] if best else 0.0
            item.match_kind = "implicit"
        else:
            # Faction was known but nothing fuzzy-matched: keep the keyword
            # faction and use the file's own name as the unit, but adopt the
            # catalog's class layer when it adds information.
            item.unit = item.name
            item.match_score = best[0] if best else 0.0
            item.match_kind = "implicit"


def build_target(item: SortItem, library: Path) -> Path:
    parts: list[str] = []
    if item.system == "Unknown":
        parts = [UNSORTED]
    else:
        parts = [item.system]
        if item.faction != UNSORTED:
            if item.group:
                parts.append(item.group)
            parts.append(item.faction)
            if item.subfaction:
                parts.append(item.subfaction)
            parts.append(item.klass or UNCLASSIFIED_CLASS)
            if item.unit:
                parts.append(_display_name(item.unit))
        else:
            parts.append(UNSORTED)
    target_dir = Path(library).joinpath(*parts)
    return target_dir / item.name


def _display_name(unit: str) -> str:
    """Implicit entries carry the original filename; strip the extension."""
    p = Path(unit)
    return p.stem if p.suffix else unit


# ---------------------------------------------------------------------------
# plan / apply
# ---------------------------------------------------------------------------

def sort_plan(
    files: list[Path],
    library: Path,
    catalog: list[dict],
    threshold: float = 0.62,
) -> list[SortItem]:
    items = []
    for f in sorted(files):
        if not f.is_file():
            continue
        if (f.name.endswith(".part") or f.name.startswith(".")
                or f.name in RUN_ARTIFACTS):
            continue
        item = inspect(f)
        classify_item(item)
        match_catalog(item, catalog, threshold)
        item.target = build_target(item, library)
        item.action = "link"
        items.append(item)
    return items


def apply_plan(items: list[SortItem], audit_path: Path) -> tuple[int, int, int]:
    """Create targets. Hardlink preferred; copy when filesystems differ.

    Returns (linked, copied, skipped).
    """
    audit_path.parent.mkdir(parents=True, exist_ok=True)
    linked = copied = skipped = 0
    with audit_path.open("a", encoding="utf-8") as audit:
        for item in items:
            src, dest = item.path, item.target
            if item.match_kind == "invalid":
                log.error("Not sorting %s: it is an HTML page, not an archive", src.name)
                skipped += 1
                continue
            if dest is None or not src.is_file():
                skipped += 1
                continue
            if dest.exists():
                log.info("Skip, target exists: %s", dest)
                skipped += 1
                continue
            dest.parent.mkdir(parents=True, exist_ok=True)
            if os.stat(src).st_dev == os.stat(dest.parent).st_dev:
                os.link(src, dest)
                item.action = "link"
                linked += 1
            else:
                log.warning(
                    "Different filesystem - COPYING instead of hardlinking %s", src.name
                )
                shutil.copy2(src, dest)
                item.action = "copy"
                copied += 1
            audit.write(json.dumps({
                "from": str(src), "to": str(dest), "action": item.action,
                "unit": item.unit, "faction": item.faction, "class": item.klass,
            }) + "\n")
    return linked, copied, skipped


def format_plan(items: list[SortItem]) -> str:
    lines = []
    for item in items:
        if item.match_kind == "invalid":
            lines.append(f"[x] {item.name} - NOT AN ARCHIVE (HTML page, bad download)")
            continue
        src = f"{item.name} ({item.size // (1024 * 1024)} MiB)" if item.size > 4 * 1024 * 1024 else item.name
        flag = {"catalog": "+", "implicit": "~", "none": "?"}[item.match_kind]
        lines.append(f"[{flag}] {src}\n      -> {item.target}")
    return "\n".join(lines)