#!/usr/bin/env python
"""
git fuzzy-checkout

Same as `git checkout branch`, but with fuzzy matching if checkout fails.
Turns `git checkout barnch` into `git checkout branch`,
assuming `branch` is a branch.
"""

import difflib
import sys

from subprocess import check_output, check_call, CalledProcessError

def git_branches():
    """construct list of git branches"""
    text = check_output(["git", "branch"]).decode('utf8', 'replace')
    return [ line.lstrip('*').strip() for line in text.splitlines() ]

def proximity(a, b):
    """measure proximity of two strings"""
    return difflib.SequenceMatcher(None, a, b).ratio()

def fuzzy_checkout(branch):
    """wrapper for git-checkout that does fuzzy-matching
    
    Helps with typos, etc. by automatically checking out the closest match
    if the initial checkout call fails.
    """
    try:
        check_call(["git", "checkout", branch])
    except CalledProcessError:
        branches = git_branches()
        branches = sorted(branches, key=lambda b : proximity(branch, b))
        best = branches[-1]
        if proximity(best, branch) > 0.6:
            print "best match for '%s': '%s' (%.1f%%)" % (branch, best, 100*proximity(best, branch))
            try:
                check_call(["git", "checkout", best])
            except CalledProcessError:
                return 1
    
    return 0

if __name__ == '__main__':
    sys.exit(fuzzy_checkout(sys.argv[1]))