#!/usr/bin/python
# -*- coding: utf-8 -*
import re
from collections import namedtuple

ext_x_targetduration = '#EXT-X-TARGETDURATION'
ext_x_media_sequence = '#EXT-X-MEDIA-SEQUENCE'
ext_x_key = '#EXT-X-KEY'
ext_x_stream_inf = '#EXT-X-STREAM-INF'
ext_x_version = '#EXT-X-VERSION'
ext_x_allow_cache = '#EXT-X-ALLOW-CACHE'
ext_x_endlist = '#EXT-X-ENDLIST'
extinf = '#EXTINF'
ATTRIBUTELISTPATTERN = re.compile(r'''((?:[^,"']|"[^"]*"|'[^']*')+)''')

def parse(content):
    data = {
        'is_variant': False,
        'is_endlist': False,
        'playlists': [],
        'segments': [],
        }
    state = {
        'expect_segment': False,
        'expect_playlist': False,
        }
    for line in string_to_lines(content):
        line = line.strip()
        if state['expect_segment']:
            _parse_ts_chunk(line, data, state)
            state['expect_segment'] = False
        elif state['expect_playlist']:
            _parse_variant_playlist(line, data, state)
            state['expect_playlist'] = False
        elif line.startswith(ext_x_targetduration):
            _parse_simple_parameter(line, data, float)
        elif line.startswith(ext_x_media_sequence):
            _parse_simple_parameter(line, data, int)
        elif line.startswith(ext_x_version):
            _parse_simple_parameter(line, data)
        elif line.startswith(ext_x_allow_cache):
            _parse_simple_parameter(line, data)
        elif line.startswith(ext_x_key):
            _parse_key(line, data)
        elif line.startswith(extinf):
            _parse_extinf(line, data, state)
            state['expect_segment'] = True
        elif line.startswith(ext_x_stream_inf):
            state['expect_playlist'] = True
            _parse_stream_inf(line, data, state)
        elif line.startswith(ext_x_endlist):
            data['is_endlist'] = True
    return data

def _parse_key(line, data):
    params = ATTRIBUTELISTPATTERN.split(line.replace(ext_x_key + ':', ''))[1::2]
    data['key'] = {}
    for param in params:
        name, value = param.split('=', 1)
        data['key'][normalize_attribute(name)] = remove_quotes(value)

def _parse_extinf(line, data, state):
    duration, title = line.replace(extinf + ':', '').split(',')
    state['segment'] = {'duration': float(duration), 'title': remove_quotes(title)}

def _parse_ts_chunk(line, data, state):
    segment = state.pop('segment')
    segment['uri'] = line
    data['segments'].append(segment)

def _parse_stream_inf(line, data, state):
    params = ATTRIBUTELISTPATTERN.split(line.replace(ext_x_stream_inf + ':', ''))[1::2]
    stream_info = {}
    for param in params:
        name, value = param.split('=', 1)
        stream_info[normalize_attribute(name)] = value

    if 'codecs' in stream_info:
        stream_info['codecs'] = remove_quotes(stream_info['codecs'])
    data['is_variant'] = True
    state['stream_info'] = stream_info

def _parse_variant_playlist(line, data, state):
    playlist = {'uri': line,
                'stream_info': state.pop('stream_info')}
    data['playlists'].append(playlist)

def _parse_simple_parameter(line, data, cast_to=str):
    param, value = line.split(':', 1)
    param = normalize_attribute(param.replace('#EXT-X-', ''))
    value = normalize_attribute(value)
    data[param] = cast_to(value)

def string_to_lines(string):
    return string.strip().replace('\r\n', '\n').split('\n')

def remove_quotes(string):
    quotes = ('"', "'")
    if string and string[0] in quotes and string[-1] in quotes:
        return string[1:-1]
    return string

def normalize_attribute(attribute):
    return attribute.replace('-', '_').lower().strip()

def is_url(uri):
    return re.match(r'https?://', uri) is not None