CUE_SHEET_EXTENSION: str = ".cue"

import os
import shutil
import logging
import subprocess
import sys
import re

from joblib import Parallel, delayed
from configparser import ConfigParser
from copy import deepcopy
from pathlib import Path
from typing import List, Optional, Tuple
from ffcuesplitter.cuesplitter import FFCueSplitter

CONFIG_FILE: str = sys.argv[1]

config = ConfigParser()
config.read(CONFIG_FILE)
SRC_FOLDER: str = config.get("source", "folder")
SRC_FILE_EXTS: List[str] = config.get("source", "file_exts").split(",")
SRC_ICON_EXTS: List[str] = config.get("source", "icon_exts").split(",")
DST_FOLDER: str = config.get("destination", "folder")
DST_FILE_EXT: str = config.get("destination", "file_ext")
DST_OVERWRITE: bool = config.get("libconv", "overwrite") == "true"
DRY_RUN: bool = config.get("libconv", "dry_run") != "false"
DEDUCE_METADATA: bool = config.get("libconv", "deduce_metadata") == "true"
FFMPEG_LOCATION: str = config.get("ffmpeg", "location")
FFMPEG_OPTS: str = config.get("ffmpeg", "options")
THREADS: int = int(config.get("libconv", "threads"))

if DST_OVERWRITE:
    FFMPEG_OPTS += " -y"

logging.basicConfig(level=logging.INFO)

cmd_list: List[str] = []

# ----------------------------------------------------------------- #
# file and folder operations

def copy(src: str, dst: str):
    logging.debug(f"copy {src} to {dst}")
    if not DRY_RUN:
        shutil.copyfile(src, dst, follow_symlinks=True)

def mkdir(path: str):
    logging.debug(f"mkdir -r {path}")
    if not DRY_RUN:
        os.makedirs(path, exist_ok=True)

def execute(command: str):
    logging.debug(f"execute: {command}")
    if not DRY_RUN:
        cmd_list.append(command)

# ----------------------------------------------------------------- #
# cue sheet processing

def cue_sheet_processor(path: str):
    dst_folder, preexisting = prepare_destination(path)

    if preexisting and not DST_OVERWRITE:
        logging.info(f"Album {path} already exists in output location and overwrite is disabled - skipping")
        return

    sheet = get_files_with_ext(path, [CUE_SHEET_EXTENSION])
    args = []

    if (len(sheet) != 1):
        logging.error(f"Expected exactly one but {path} contains {len(sheet)} cue sheets - trying file processor")
        file_processor(path)
        return

    try:
        data = FFCueSplitter(sheet[0], dry=DRY_RUN, outputdir=dst_folder, suffix=DST_FILE_EXT, overwrite=DST_OVERWRITE, ffmpeg_cmd=FFMPEG_LOCATION, ffmpeg_add_params=FFMPEG_OPTS)
        data.open_cuefile()
        args = data.ffmpeg_arguments()["arguments"]
    except:
        logging.error(f"Error during parsing of cuesheet {path} - trying file processor")
        file_processor(path)
        return

    for arg in args:
        arg_end = arg.find("-y")
        filename = arg[arg_end + 5:-1]
        arg = arg[:arg_end]
        execute(f"{arg} \"{dst_folder}{filename}\"")

# ----------------------------------------------------------------- #
# basic "folder contains audio files" processing

def metadata_from_folder(path: str) -> str:
    # this method has to be adapted to your individual folder structure
    # if there is none then do nothing as by default this is not used
    if not DEDUCE_METADATA:
        return ""

    path = os.path.normpath(path)
    folders = path.split(os.sep)

    logging.debug(f"deducing metadata from folders: {folders}")

    album_name = re.sub(r'[ ]*\(.*?\)', '', folders[-1])
    comment = folders[-1].replace(album_name, "").replace("(", "").replace(")", "").replace(" ","")

    logging.debug(f"got metadata: album={album_name} comment={comment} artist={folders[-2]} genre={folders[-3]}")
    
    return f"-metadata ALBUM=\"{album_name}\" -metadata COMMENT=\"{comment}\" -metadata ARTIST=\"{folders[-2]}\" -metadata GENRE=\"{folders[-3]}\""

def metadata_from_file(filename: str) -> str:
    title=""
    number=""

    if re.match(r'[0-9]+[ ]*-[ ]*[.]*', filename):
        logging.debug(f"file {filename} matched metadata regex #1")
        number = re.search(r'[0-9]+[ ]*-[ ]*', filename).group()
        title = filename.replace(number, "")
        number = re.sub(r'[ ]*-[ ]*', '', number)
    elif re.match(r'[0-9]+\.[ ]*[.]*', filename):
        logging.debug(f"file {filename} matched metadata regex #2")
        number = re.search(r'[0-9]+\.[ ]*', filename).group()
        title = filename.replace(number, "")
        number = re.sub(r'\.[ ]*', "", number)
    else:
        logging.debug(f"file {filename} matched no metadata regex")

    return f"-metadata TITLE=\"{title}\" -metadata TRACK=\"{number}\""

def file_processor(path: str):
    dst_folder, preexisting = prepare_destination(path)

    if preexisting and not DST_OVERWRITE:
        logging.info(f"Album {path} already exists in output location and overwrite is disabled - skipping")
        return

    files = get_files_with_ext(path, SRC_FILE_EXTS)
    album_metadata = metadata_from_folder(path)

    for file in files:
        filename = get_filename(file, path)
        file_metadata = metadata_from_file(filename[1:])
        execute(f"\"{FFMPEG_LOCATION}\" -i \"{file}\" {FFMPEG_OPTS} {album_metadata} {file_metadata} \"{dst_folder + filename}.{DST_FILE_EXT}\"")

# ----------------------------------------------------------------- #
# Iteration over library folders and preparation

def contains_extension(path: str, extensions: List[str]) -> bool:
    logging.debug(f"searching for extensions {extensions} in {path}")
    for root, dirs, files in os.walk(path):
        for file in files:
            for ext in extensions:
                if file.endswith(ext):
                    logging.debug(f"file {file} matched extension '{ext}'")
                    return True
        # needed to prevent recursive search
        break
    return False

def get_files_with_ext(path: str, extensions: List[str]) -> List[str]:
    logging.debug(f"obtainint all files with extensions {extensions} from {path}")
    ret_files = []
    for root, dirs, files in os.walk(path):
        for file in files:
            for ext in extensions:
                if file.endswith(ext):
                    logging.debug(f"file {file} matched extension '{ext}'")
                    ret_files.append(os.path.join(root, file))
                    # file is added now - no need to check the other extensions
                    break
        # needed to prevent recursive search
        break
    return ret_files

def prepare_destination(path: str) -> Tuple[str,bool]:
    images = get_files_with_ext(path, SRC_ICON_EXTS)

    sub_path = path.replace(SRC_FOLDER, "")
    new_path = DST_FOLDER + sub_path
    mkdir(new_path)

    existing: bool = len(os.listdir(new_path)) != 0

    for img in images:
        img_name = img.replace(path, "")
        new_img_path = new_path + img_name
        copy(img, new_img_path)

    return (new_path,existing)
        
def get_filename(file: str, path: str) -> str:
    fname = file.replace(path, "")
    for ext in SRC_FILE_EXTS:
        fname = fname.replace("." + ext, "")
    return fname

def scan_folder(path: str):
    for root, dirs, files in os.walk(path):
        for directory in dirs:
            process_folder(os.path.join(root, directory))
        # needed to prevent recursive search
        break

def process_folder(path: str):
    logging.info(f"Visiting folder '{path}'")
    if contains_extension(path, [CUE_SHEET_EXTENSION]):
        logging.info("found cuesheet")
        cue_sheet_processor(path)
    elif contains_extension(path, SRC_FILE_EXTS):
        logging.info("found audio files")
        file_processor(path)
    else:
        logging.info("scanning subfolders")
        scan_folder(path)

def execute_command_list():
    logging.info(f"Executing all {len(cmd_list)} commands with {THREADS} parallel threads")

    if DRY_RUN:
        logging.info("Skipping execution as we are dry-running. Printing list as debug-info.")
        logging.debug(str(cmd_list))
        return

    Parallel(n_jobs=THREADS)(
        delayed(os.system)(cmd) for cmd in cmd_list
    )

if __name__ == "__main__":
    logging.info(f"Using settings from {CONFIG_FILE}")

    if DRY_RUN:
        logging.info("Executing as DRY RUN")
    if DST_OVERWRITE:
        logging.info("Overwrite of existing files active")

    process_folder(SRC_FOLDER)
    execute_command_list()