#!/usr/bin/python3

import argparse
import os

from config import Config
from log import INFO
from model import Tracks, session
from pydub import AudioSegment
from tinytag import TinyTag


def main():
    "Main loop"

    INFO("Starting")

    # Parse command line
    p = argparse.ArgumentParser()
    p.add_argument('-u', '--update',
                   action="store_true", dest="update",
                   default=True, help="Update database")
    args = p.parse_args()

    # Run as required
    if args.update:
        INFO("Updating database")
        update_db()

    INFO("Finished")


def add_path_to_db(path):
    "Add passed path to database along with metadata"

    track = Tracks.get_or_create(path)
    tag = TinyTag.get(path)
    audio = get_audio_segment(path)

    track.title = tag.title
    track.artist = tag.artist
    track.duration = int(round(tag.duration,
                               Config.MILLISECOND_SIGFIGS) * 1000)
    track.start_gap = leading_silence(audio)
    track.fade_at = round(fade_point(audio) / 1000,
                          Config.MILLISECOND_SIGFIGS) * 1000
    track.silence_at = round(trailing_silence(audio) / 1000,
                             Config.MILLISECOND_SIGFIGS) * 1000
    track.mtime = os.path.getmtime(path)
    session.commit()


def get_audio_segment(path):
    try:
        if path.endswith('.mp3'):
            return AudioSegment.from_mp3(path)
        elif path.endswith('.flac'):
            return AudioSegment.from_file(path, "flac")
    except AttributeError:
        return None


def leading_silence(audio_segment, silence_threshold=Config.DBFS_SILENCE,
                    chunk_size=Config.AUDIO_SEGMENT_CHUNK_SIZE):
    """
    Returns the millisecond/index that the leading silence ends.
    audio_segment - the segment to find silence in
    silence_threshold - the upper bound for how quiet is silent in dFBS
    chunk_size - chunk size for interating over the segment in ms

    https://github.com/jiaaro/pydub/blob/master/pydub/silence.py
    """

    trim_ms = 0  # ms
    assert chunk_size > 0  # to avoid infinite loop
    while (
        audio_segment[trim_ms:trim_ms + chunk_size].dBFS <      # noqa W504
            silence_threshold and trim_ms < len(audio_segment)):
        trim_ms += chunk_size

    # if there is no end it should return the length of the segment
    return min(trim_ms, len(audio_segment))


def fade_point(audio_segment, fade_threshold=Config.DBFS_FADE,
               chunk_size=Config.AUDIO_SEGMENT_CHUNK_SIZE):
    """
    Returns the millisecond/index of the point where the fade is down to
    fade_threshold and doesn't get louder again.
    audio_segment - the sdlg_search_database_uiegment to find silence in
    fade_threshold - the upper bound for how quiet is silent in dFBS
    chunk_size - chunk size for interating over the segment in ms
    """

    assert chunk_size > 0  # to avoid infinite loop

    segment_length = audio_segment.duration_seconds * 1000  # ms
    trim_ms = segment_length - chunk_size
    while (
        audio_segment[trim_ms:trim_ms + chunk_size].dBFS < fade_threshold
            and trim_ms > 0):       # noqa W503
        trim_ms -= chunk_size

    # if there is no trailing silence, return lenght of track (it's less
    # the chunk_size, but for chunk_size = 10ms, this may be ignored)
    return int(trim_ms)


def trailing_silence(audio_segment, silence_threshold=-50.0,
                     chunk_size=Config.AUDIO_SEGMENT_CHUNK_SIZE):
    return fade_point(audio_segment, silence_threshold, chunk_size)


def update_db():
    """
    Repopulate database
    """

    # Search for tracks in only one of directory and database

    db_paths = set(Tracks.get_all_paths())

    os_paths_list = []
    for root, dirs, files in os.walk(Config.ROOT):
        for f in files:
            path = os.path.join(root, f)
            ext = os.path.splitext(f)[1]
            if ext in [".flac", ".mp3"]:
                os_paths_list.append(path)
    os_paths = set(os_paths_list)

    for path in list(db_paths - os_paths):
        INFO(f"To remove from database: {path}")

    for path in list(os_paths - db_paths):
        INFO(f"Adding to datbase: {path}")
        add_path_to_db(path)


if __name__ == '__main__':
    main()