utils.py

#!/usr/bin/env python
# coding=utf-8

import collections
import importlib
import re

INSTRUMENT_CHOICES = dict(
    uke='ukulele',
    guitar='guitar',
    guitardd='guitar (drop d)',
    mando='mandolin')

FLATS_TO_SHARPS = {
    'cb': 'b',
    'db': 'c#',
    'eb': 'd#',
    'fb': 'e',
    'gb': 'f#',
    'ab': 'g#',
    'bb': 'a#'
}


def diffs(items):  # -1 for X
    items = [i for i in items if i > -1]
    return [j-i for i, j in zip(items[:-1], items[1:])]


def shape_to_diff_id(pattern):
    return ''.join(map(str, diffs(pattern)))


def build_diff_dict(chords):
    diff = collections.defaultdict(list)
    for chord, pattern in chords:
        diff[shape_to_diff_id(pattern)].append((chord, pattern))
    return diff


def with_same_pattern(pattern, by_diff):
    ret = list(filter(lambda x: x[1] != pattern, by_diff.get(shape_to_diff_id(pattern))))
    return ret or []


def render(pattern, strings, padd=0):
    DIM, DIM_RESET = '\033[2m', '\033[22m'
    BAR = '|-%s-'

    min_, max_ = min(pattern), max(pattern)+1
    bars = range(min_-1 if min_ > 1 else 1, max_+1)
    print(' ' * padd + ' ' * 3, ' '.join([str(i).ljust(3, ' ') for i in bars]))
    for string, note in zip(reversed(strings), reversed(pattern)):
        muted = note < 0
        line = [BAR % 'O' if note == i else BAR % '-' for i in bars]
        line = ''.join(line)
        line = ('X' if muted else '|') + line[1:]
        print(' ' * padd + '%s%s %s|%s' % (('', DIM)[muted], string,
                                           ''.join(line), ('', DIM_RESET)[muted]))


def get_instrument(instrument):
    instrument = importlib.import_module(instrument)
    return instrument.STRINGS, instrument.CHORDS


def normalize_chord(chord):
    def _replace(x):
        return FLATS_TO_SHARPS.get(x.group(0))

    return re.sub(r'[a-g]b', _replace, chord, flags=re.IGNORECASE)