"""File operation helpers for the import flow."""

from __future__ import annotations

import logging
import os
import shutil
import subprocess
import time
from pathlib import Path

from config.settings import config_manager

logger = logging.getLogger("imports.file_ops")


def safe_move_file(src, dst):
    """Move a file safely across filesystems."""
    src = Path(src)
    dst = Path(dst)

    dst.parent.mkdir(parents=True, exist_ok=True)

    if not src.exists():
        if dst.exists():
            logger.info(f"Source gone but destination exists, file already transferred: {dst.name}")
            return
        raise FileNotFoundError(f"Source file not found and destination does not exist: {src}")

    if dst.exists():
        for _attempt in range(3):
            try:
                dst.unlink()
                break
            except PermissionError:
                if _attempt < 2:
                    time.sleep(1)
                else:
                    logger.warning(f"Could not remove locked destination after 3 attempts: {dst.name}")
            except Exception:
                break

    try:
        shutil.move(str(src), str(dst))
        return
    except FileNotFoundError:
        if dst.exists():
            logger.info(f"Source moved by another thread, destination exists: {dst.name}")
            return
        raise
    except (OSError, PermissionError) as e:
        error_msg = str(e).lower()

        if dst.exists() and dst.stat().st_size > 0:
            logger.warning(f"Move raised {type(e).__name__} but destination exists, treating as success: {e}")
            try:
                src.unlink()
            except Exception:
                logger.info(f"Could not delete source file (may be owned by another process): {src}")
            return

        if "cross-device" in error_msg or "operation not permitted" in error_msg or "permission denied" in error_msg:
            logger.warning(f"Cross-device move detected, using fallback copy method: {e}")
            try:
                with open(src, "rb") as f_src:
                    with open(dst, "wb") as f_dst:
                        shutil.copyfileobj(f_src, f_dst)
                        f_dst.flush()
                        os.fsync(f_dst.fileno())

                try:
                    src.unlink()
                except PermissionError:
                    logger.info(f"Could not delete source file (may be owned by another process): {src}")
                logger.info(f"Successfully moved file using fallback method: {src} -> {dst}")
                return
            except Exception as fallback_error:
                logger.error(f"Fallback copy also failed: {fallback_error}")
                raise
        raise


def cleanup_empty_directories(download_path, moved_file_path):
    """Remove empty directories after a move, ignoring hidden files."""
    try:
        current_dir = os.path.dirname(moved_file_path)
        while current_dir != download_path and current_dir.startswith(download_path):
            is_empty = not any(not f.startswith(".") for f in os.listdir(current_dir))
            if is_empty:
                logger.warning(f"Removing empty directory: {current_dir}")
                os.rmdir(current_dir)
                current_dir = os.path.dirname(current_dir)
            else:
                break
    except Exception as e:
        logger.error(f"An error occurred during directory cleanup: {e}")


def get_audio_quality_string(file_path):
    """Return a compact audio quality string for the given file."""
    try:
        ext = os.path.splitext(file_path)[1].lower()

        if ext == ".flac":
            from mutagen.flac import FLAC
            audio = FLAC(file_path)
            return f"FLAC {audio.info.bits_per_sample}bit"

        if ext == ".mp3":
            from mutagen.mp3 import MP3, BitrateMode

            audio = MP3(file_path)
            bitrate_kbps = audio.info.bitrate // 1000
            if audio.info.bitrate_mode == BitrateMode.VBR:
                return "MP3-VBR"
            return f"MP3-{bitrate_kbps}"

        if ext in (".m4a", ".aac", ".mp4"):
            from mutagen.mp4 import MP4
            audio = MP4(file_path)
            return f"M4A-{audio.info.bitrate // 1000}"

        if ext == ".ogg":
            from mutagen.oggvorbis import OggVorbis
            audio = OggVorbis(file_path)
            return f"OGG-{audio.info.bitrate // 1000}"

        if ext == ".opus":
            from mutagen.oggopus import OggOpus

            audio = OggOpus(file_path)
            return f"OPUS-{audio.info.bitrate // 1000}"

        return ""
    except Exception as e:
        logger.debug(f"Could not determine audio quality for {file_path}: {e}")
        return ""


def get_quality_tier_from_extension(file_path):
    """Classify a file extension into a quality tier."""
    if not file_path:
        return ("unknown", 999)

    ext = os.path.splitext(file_path)[1].lower()
    quality_tiers = {
        "lossless": {
            "extensions": [".flac", ".ape", ".wav", ".alac", ".dsf", ".dff", ".aiff", ".aif"],
            "tier": 1,
        },
        "high_lossy": {
            "extensions": [".opus", ".ogg"],
            "tier": 2,
        },
        "standard_lossy": {
            "extensions": [".m4a", ".aac"],
            "tier": 3,
        },
        "low_lossy": {
            "extensions": [".mp3", ".wma"],
            "tier": 4,
        },
    }

    for tier_name, tier_data in quality_tiers.items():
        if ext in tier_data["extensions"]:
            return (tier_name, tier_data["tier"])

    return ("unknown", 999)


def downsample_hires_flac(final_path, context):
    """Downsample a hi-res FLAC to 16-bit/44.1kHz if enabled."""
    from mutagen.flac import FLAC

    if not config_manager.get("lossy_copy.downsample_hires", False):
        return None

    if os.path.splitext(final_path)[1].lower() != ".flac":
        return None

    try:
        audio = FLAC(final_path)
        original_bits = audio.info.bits_per_sample
        original_rate = audio.info.sample_rate
    except Exception as e:
        logger.error(f"[Downsample] Could not read FLAC info: {e}")
        return None

    if original_bits <= 16 and original_rate <= 44100:
        return None

    logger.info(f"[Downsample] Converting {original_bits}-bit/{original_rate}Hz -> 16-bit/44100Hz: {os.path.basename(final_path)}")

    ffmpeg_bin = shutil.which("ffmpeg")
    if not ffmpeg_bin:
        local = os.path.join(os.path.dirname(__file__), "tools", "ffmpeg")
        if os.path.isfile(local):
            ffmpeg_bin = local
        else:
            logger.warning("[Downsample] ffmpeg not found - skipping hi-res conversion")
            return None

    temp_path = final_path + ".tmp.flac"
    try:
        result = subprocess.run(
            [
                ffmpeg_bin, "-i", final_path,
                "-sample_fmt", "s16",
                "-ar", "44100",
                "-map_metadata", "0",
                "-compression_level", "8",
                "-y", temp_path,
            ],
            capture_output=True,
            text=True,
            timeout=300,
        )

        if result.returncode != 0:
            logger.error(f"[Downsample] ffmpeg failed: {result.stderr[:200]}")
            if os.path.exists(temp_path):
                os.remove(temp_path)
            return None

        if not os.path.isfile(temp_path) or os.path.getsize(temp_path) == 0:
            logger.warning("[Downsample] Output file missing or empty")
            if os.path.exists(temp_path):
                os.remove(temp_path)
            return None

        verify_audio = FLAC(temp_path)
        if verify_audio.info.bits_per_sample != 16:
            logger.info(f"[Downsample] Output not 16-bit ({verify_audio.info.bits_per_sample}-bit), aborting")
            os.remove(temp_path)
            return None

        os.replace(temp_path, final_path)
        logger.info(f"[Downsample] Converted to 16-bit/44.1kHz: {os.path.basename(final_path)}")

        new_quality = "FLAC 16bit"
        try:
            updated_audio = FLAC(final_path)
            updated_audio["QUALITY"] = new_quality
            updated_audio.save()
        except Exception as tag_err:
            logger.error(f"[Downsample] Could not update QUALITY tag: {tag_err}")

        old_quality = context.get("_audio_quality", "")
        context["_audio_quality"] = new_quality

        if old_quality and old_quality != new_quality and old_quality in os.path.basename(final_path):
            new_basename = os.path.basename(final_path).replace(old_quality, new_quality)
            new_path = os.path.join(os.path.dirname(final_path), new_basename)
            try:
                os.rename(final_path, new_path)
                logger.info(f"[Downsample] Renamed: {os.path.basename(final_path)} -> {new_basename}")
                for lyrics_ext in (".lrc", ".txt"):
                    old_lyrics = os.path.splitext(final_path)[0] + lyrics_ext
                    if os.path.isfile(old_lyrics):
                        new_lyrics = os.path.splitext(new_path)[0] + lyrics_ext
                        os.rename(old_lyrics, new_lyrics)
                return new_path
            except Exception as rename_err:
                logger.error(f"[Downsample] Could not rename file: {rename_err}")

        return final_path
    except subprocess.TimeoutExpired:
        logger.info(f"[Downsample] Conversion timed out for: {os.path.basename(final_path)}")
        if os.path.exists(temp_path):
            os.remove(temp_path)
    except Exception as e:
        logger.error(f"[Downsample] Conversion error: {e}")
        if os.path.exists(temp_path):
            try:
                os.remove(temp_path)
            except Exception:
                pass
    return None


def create_lossy_copy(final_path):
    """Convert a FLAC file to a lossy copy using the configured codec."""
    from mutagen.flac import FLAC

    if not config_manager.get("lossy_copy.enabled", False):
        return None

    if os.path.splitext(final_path)[1].lower() != ".flac":
        return None

    codec = config_manager.get("lossy_copy.codec", "mp3").lower()
    bitrate = config_manager.get("lossy_copy.bitrate", "320")

    if codec == "opus" and int(bitrate) > 256:
        bitrate = "256"

    codec_map = {
        "mp3": ("libmp3lame", ".mp3", f"MP3-{bitrate}", ["-vn", "-id3v2_version", "3"]),
        "opus": ("libopus", ".opus", f"OPUS-{bitrate}", ["-vn", "-map", "0:a", "-vbr", "on"]),
        "aac": ("aac", ".m4a", f"AAC-{bitrate}", ["-vn", "-movflags", "+faststart"]),
    }

    if codec not in codec_map:
        logger.info(f"[Lossy Copy] Unknown codec '{codec}' - skipping conversion")
        return None

    ffmpeg_codec, out_ext, quality_label, extra_args = codec_map[codec]
    out_path = os.path.splitext(final_path)[0] + out_ext

    original_quality = get_audio_quality_string(final_path)
    if original_quality:
        out_basename = os.path.basename(out_path)
        if original_quality in out_basename:
            out_basename = out_basename.replace(original_quality, quality_label)
            out_path = os.path.join(os.path.dirname(out_path), out_basename)

    ffmpeg_bin = shutil.which("ffmpeg")
    if not ffmpeg_bin:
        local = os.path.join(os.path.dirname(__file__), "tools", "ffmpeg")
        if os.path.isfile(local):
            ffmpeg_bin = local
        else:
            logger.warning(f"[Lossy Copy] ffmpeg not found - skipping {codec.upper()} conversion")
            return None

    try:
        logger.info(f"[Lossy Copy] Converting to {quality_label}: {os.path.basename(final_path)}")
        cmd = [
            ffmpeg_bin, "-i", final_path,
            "-codec:a", ffmpeg_codec,
            "-b:a", f"{bitrate}k",
            "-map_metadata", "0",
        ] + extra_args + ["-y", out_path]

        result = subprocess.run(cmd, capture_output=True, text=True, timeout=120)

        if result.returncode == 0:
            logger.info(f"[Lossy Copy] Created {quality_label} copy: {os.path.basename(out_path)}")
            try:
                from mutagen import File as MutagenFile
                audio = MutagenFile(out_path)
                if audio is not None:
                    if codec == "mp3":
                        from mutagen.id3 import TXXX
                        audio.tags.add(TXXX(encoding=3, desc="QUALITY", text=[quality_label]))
                    elif codec == "opus":
                        audio["QUALITY"] = [quality_label]
                    elif codec == "aac":
                        from mutagen.mp4 import MP4FreeForm
                        audio["----:com.apple.iTunes:QUALITY"] = [MP4FreeForm(quality_label.encode("utf-8"))]
                    audio.save()
            except Exception as tag_err:
                logger.error(f"[Lossy Copy] Could not update QUALITY tag: {tag_err}")
            return out_path

        logger.error(f"[Lossy Copy] ffmpeg failed: {result.stderr[:200]}")
        if os.path.exists(out_path):
            try:
                os.remove(out_path)
            except Exception:
                pass
        return None
    except subprocess.TimeoutExpired:
        logger.warning(f"[Lossy Copy] Conversion timed out for: {os.path.basename(final_path)}")
    except Exception as e:
        logger.error(f"[Lossy Copy] Conversion error: {e}")
    return None