"""
processor.py - Archive extraction and hit searching logic.

Supports: .txt, .zip, .7z, .rar
Stream-processes files line by line - safe for large combo lists.
"""

import rarfile
rarfile.UNRAR_TOOL = "unrar"

import re
import zipfile
import logging
import shutil
from pathlib import Path

try:
    import py7zr
    HAS_7Z = True
except ImportError:
    HAS_7Z = False

try:
    import rarfile
    HAS_RAR = True
except ImportError:
    HAS_RAR = False

from config import ARCHIVE_PASSWORDS

log = logging.getLogger(__name__)


# ─── Searching ───────────────────────────────────────────────────────────────

def compile_patterns(keywords: list[str]) -> list[re.Pattern]:
    return [re.compile(kw, re.IGNORECASE) for kw in keywords]


def search_file(filepath: Path, patterns: list[re.Pattern]) -> list[str]:
    """
    Stream-reads a text file line by line and returns lines matching any pattern.
    Ignores encoding errors - combo files are often messy.
    """
    hits: list[str] = []
    try:
        with open(filepath, "r", encoding="utf-8", errors="ignore") as f:
            for line in f:
                stripped = line.strip()
                if stripped and any(p.search(stripped) for p in patterns):
                    hits.append(stripped)
    except Exception as e:
        log.warning(f"Could not read {filepath.name}: {e}")
    return hits


# ─── Extraction ──────────────────────────────────────────────────────────────

def _try_passwords(extract_fn, passwords: list[bytes]) -> bool:
    """Try a list of passwords against an extract function. Returns True on success."""
    for pwd in passwords:
        try:
            extract_fn(pwd)
            return True
        except Exception:
            continue
    return False


def extract_zip(filepath: Path, dest: Path, extra_password: str | None = None) -> list[Path]:
    passwords = ARCHIVE_PASSWORDS.copy()
    if extra_password:
        passwords.insert(0, extra_password.encode())
    extracted: list[Path] = []
    try:
        with zipfile.ZipFile(filepath) as zf:
            def try_extract(pwd: bytes):
                zf.extractall(dest, pwd=pwd or None)

            try:
                zf.extractall(dest)
            except RuntimeError:
                log.info(f"  ZIP is password-protected, trying common passwords...")
                if not _try_passwords(try_extract, ARCHIVE_PASSWORDS):
                    log.warning(f"  Could not unlock {filepath.name} - skipping.")
                    return []

            extracted = [p for p in dest.rglob("*") if p.is_file()]
    except zipfile.BadZipFile:
        log.warning(f"  {filepath.name} is not a valid ZIP.")
    except Exception as e:
        log.warning(f"  ZIP extraction error on {filepath.name}: {e}")
    return extracted


def extract_7z(filepath: Path, dest: Path, extra_password: str | None = None) -> list[Path]:
    if not HAS_7Z:
        log.warning("py7zr not installed - skipping .7z file.")
        return []
    extracted: list[Path] = []
    passwords = ARCHIVE_PASSWORDS.copy()
    if extra_password:
        passwords.insert(0, extra_password.encode())

    try:
        # Try without password first
        try:
            with py7zr.SevenZipFile(filepath, mode="r") as z:
                z.extractall(dest)
        except py7zr.exceptions.PasswordRequired:
            log.info(f"  7z is password-protected, trying common passwords...")
            success = False
            for pwd in ARCHIVE_PASSWORDS:
                try:
                    with py7zr.SevenZipFile(filepath, mode="r", password=pwd.decode()) as z:
                        z.extractall(dest)
                    success = True
                    break
                except Exception:
                    continue
            if not success:
                log.warning(f"  Could not unlock {filepath.name} - skipping.")
                return []

        extracted = [p for p in dest.rglob("*") if p.is_file()]
    except Exception as e:
        log.warning(f"  7z extraction error on {filepath.name}: {e}")
    return extracted


def extract_rar(filepath: Path, dest: Path, extra_password: str | None = None) -> list[Path]:
    if not HAS_RAR:
        log.warning("rarfile not installed - skipping .rar file.")
        return []

    passwords = ARCHIVE_PASSWORDS.copy()
    if extra_password:
        passwords.insert(0, extra_password.encode())
    extracted: list[Path] = []
    try:
        with rarfile.RarFile(filepath) as rf:
            def try_extract(pwd: bytes):
                rf.extractall(dest, pwd=pwd.decode() if pwd else None)

            try:
                rf.extractall(dest)
            except rarfile.BadRarFile:
                log.warning(f"  {filepath.name} is not a valid RAR.")
                return []
            except Exception:
                log.info(f"  RAR may be password-protected, trying common passwords...")
                if not _try_passwords(try_extract, ARCHIVE_PASSWORDS):
                    log.warning(f"  Could not unlock {filepath.name} - skipping.")
                    return []

        extracted = [p for p in dest.rglob("*") if p.is_file()]
    except Exception as e:
        log.warning(f"  RAR extraction error on {filepath.name}: {e}")
    return extracted


def unpack(filepath: Path, extra_password: str | None = None) -> tuple[list[Path], Path | None]:
    """
    Unpacks an archive into a sibling directory.
    Returns (list of extracted files, extract_dir or None).
    If it's not an archive, returns ([filepath], None).
    """
    suffix = filepath.suffix.lower()
    extract_dir = filepath.parent / filepath.stem

    if suffix == ".zip":
        extract_dir.mkdir(exist_ok=True)
        files = extract_zip(filepath, extract_dir, extra_password)
        return files, extract_dir

    elif suffix == ".7z":
        extract_dir.mkdir(exist_ok=True)
        files = extract_7z(filepath, extract_dir, extra_password)
        return files, extract_dir

    elif suffix == ".rar":
        extract_dir.mkdir(exist_ok=True)
        files = extract_rar(filepath, extract_dir, extra_password)
        return files, extract_dir

    else:
        # Plain file - return as-is, no extract dir to clean up
        return [filepath], None


# ─── Main entry point ────────────────────────────────────────────────────────

def process_file(filepath: Path, patterns, password: str | None = None) -> list[str]:
    """
    Full pipeline: unpack → search each file → clean up everything.
    Returns list of matching lines (hits).
    """
    log.info(f"  Processing: {filepath.name}")
    all_hits: list[str] = []

    files, extract_dir = unpack(filepath, extra_password=password)

    for f in files:
        if f.suffix.lower() == ".txt":
            hits = search_file(f, patterns)
            if hits:
                log.info(f"    ✓ {len(hits)} hit(s) in {f.name}")
            all_hits.extend(hits)

        # Nested archives - recurse one level
        elif f.suffix.lower() in {".zip", ".7z", ".rar"} and f != filepath:
            log.info(f"    → Nested archive: {f.name}")
            nested_hits = process_file(f, patterns)
            all_hits.extend(nested_hits)
            continue  # process_file already cleaned up f

        # Clean up extracted file
        try:
            f.unlink(missing_ok=True)
        except Exception:
            pass

    # Clean up extract dir
    if extract_dir and extract_dir.exists():
        shutil.rmtree(extract_dir, ignore_errors=True)

    # Clean up original download
    try:
        filepath.unlink(missing_ok=True)
    except Exception:
        pass

    return all_hits