#!/usr/bin/env python3
"""
Music streaming.
"""
import os
import re
import json
import random
import subprocess
from urllib import parse

from flask import Flask, Response, render_template, send_file
import mutagen

MUSIC_DIR = "/mnt/music/Music"
MUSIC_EXT = ['flac', 'mp3', 'wav', 'm4a']
FFMPEG_CMD = [
	'ffmpeg', '-y',
	'-loglevel', 'panic',
	'-i', '',
	'-codec:a', 'libopus',
	'-b:a', '64k',
	'-f', 'opus',
	'-'
]

class Track:
	def __init__(self, filepath=None, d=None):
		if d:
			self._from_dict(d)
			return

		if filepath.endswith("mp3"):
			m = mutagen.mp3.EasyMP3(filepath)
		else:
			m = mutagen.File(filepath)
		self.title = m.get('title', [''])[0]
		self.artist = m.get('artist', [''])[0]
		self.ablum = m.get('album', [''])[0]
		self.date = m.get('date', [''])[0]
		self.length = str(int(m.info.length) // 60) + ":"
		self.length += str(int(m.info.length) % 60)
		self.filepath = filepath

	def _from_dict(self, d):
		self.title = d.get('title')
		self.artist = d.get('artist')
		self.ablum = d.get('album')
		self.date = d.get('date')
		self.length = d.get('length')
		self.filepath = d.get('filepath')


def build_library(root_dir):
	"""Walks the music directory and builds a library of tracks."""
	print("Building library")
	tracks = []
	for dir_name, sub_dirs, files in os.walk(root_dir):
		for file in files:
			if not os.path.splitext(file)[1][1:] in MUSIC_EXT:
				continue
			filepath = os.path.join(root_dir, dir_name, file)
			track = Track(filepath)
			tracks.append(track)
	return tracks

def init_library():
	"""Loads the library from file, or builds a new one if one isn't found."""
	if os.path.isfile("library.json"):
		with open("library.json", "r") as file:
			tracks = json.loads(file.read())
		tracks = [Track(d=d) for d in tracks]
	else:
		tracks = build_library(MUSIC_DIR)
		with open("library.json", "w") as file:
			file.write(json.dumps([t.__dict__ for t in tracks]))
	return tracks


app = Flask(__name__)
tracks = init_library()

@app.route('/')
def index():
	"""Main index page."""
	nav_items = list(set(t.artist for t in tracks))
	nav_items.sort()
	nav_items = [item + '/' for item in nav_items]
	cd = "/"
	return render_template('index.html', **locals())


@app.route('/stream/<path:track>')
def stream(track):
	"""View for the raw audio file."""
	track = parse.unquote(track)
	path = os.path.join(MUSIC_DIR, track)
	path = os.path.abspath(path)
	if not path.startswith(MUSIC_DIR):
		return "False"
	if not os.path.isfile(path):
		return "False"
	FFMPEG_CMD[5] = path

	def generate():
		with subprocess.Popen(FFMPEG_CMD, stdout=subprocess.PIPE) as proc:
			data = proc.stdout.read(1024)
			while data:
				yield data
				data = proc.stdout.read(1024)
	return Response(generate(), mimetype="audio/ogg")


@app.route('/get_dir/<path:directory>/')
@app.route('/get_dir/')
def get_dir(directory=""):
	"""Returns the contents of the requested directory."""
	directory = directory.replace("DOTDOT", "..")
	directory = os.path.join(MUSIC_DIR, directory)
	directory = os.path.abspath(directory)
	if not directory.startswith(MUSIC_DIR):
		return "False"
	if not os.path.isdir(directory):
		return "False"

	nav_items = os.listdir(directory)
	nav_items.sort()
	if directory != MUSIC_DIR:
		nav_items = [".."] + nav_items

	nav_items_new = []
	for item in nav_items:
		if os.path.isdir(os.path.join(directory, item)):
			item += '/'
		nav_items_new.append(item)
	nav_items_new = [directory.replace(MUSIC_DIR, '') + '/'] + nav_items_new

	return json.dumps(nav_items_new)


@app.route('/get_shuffle')
def shuffle():
	"""Returns a randomly selected track from the library."""
	item = random.choice(os.listdir(MUSIC_DIR))
	path = os.path.join(MUSIC_DIR, item)
	n = 0
	while not item.rpartition('.')[2] in MUSIC_EXT:
		n += 1
		item = random.choice(os.listdir(path))
		if os.path.isdir(os.path.join(path, item)):
			path = os.path.join(path, item)
		if n == 5:
			item = random.choice(os.listdir(MUSIC_DIR))
			path = os.path.join(MUSIC_DIR, item)
			n = 0
	path = os.path.join(path, item)
	return path.replace(MUSIC_DIR, '')


@app.route('/album_cover/<path:cover>')
def album_cover(cover):
	"""View for the raw audio file."""
	path = os.path.join(MUSIC_DIR, cover)
	path = os.path.abspath(path)
	if not path.startswith(MUSIC_DIR):
		return "False"
	if not os.path.isfile(path):
		return "False"

	return send_file(path)


if __name__ == "__main__":
	app.run(host='0.0.0.0', port=5150)