#!/usr/bin/python

import sys
import getopt
import os
from os.path import expanduser

def main(argv):
    userName = "user"
    gopath = "golang"

    try:
        opts, args = getopt.getopt(argv, "hug:d", ["help", "user=", "gopath="])
    except getopt.GetoptError:
        usage()
        sys.exit(2)

    for opt, arg in opts:
        if opt in ("-h", "--help"):
            usage()
            sys.exit()
        elif opt == '-d':
            global _debug
            _debug = 1
        elif opt in ("-u", "--user"):
            userName = arg
        elif opt in ("-g", "--gopath"):
            gopath = arg

    home = expanduser("~")
    bashrc = home + "/.bashrc"
    zshrc = home + "/.zshrc"

    os.system("mkdir %s" % home + "/" + gopath)
    if not userName == "user":
        os.system("mkdir -p %s" % home + "/src/github.com/" + userName)

    append_line_to_file("export GOPATH=$gopath", bashrc)
    append_line_to_file("export GOROOT=/usr/local/opt/go/libexec", bashrc)
    append_line_to_file("export PATH=$PATH:$GOPATH/bin", bashrc)
    append_line_to_file("export PATH=$PATH:$GOROOT/bin", bashrc)

    append_line_to_file("export GOPATH=$gopath", zshrc)
    append_line_to_file("export GOROOT=/usr/local/opt/go/libexec", zshrc)
    append_line_to_file("export PATH=$PATH:$GOPATH/bin", zshrc)
    append_line_to_file("export PATH=$PATH:$GOROOT/bin", zshrc)

    if (which("brew") == None):
        installBrew = query_yes_no("Do you want to intstall brew?")
        if installBrew:
            success = os.system('ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"')
            if success == False:
                print "Failed to install brew! Maybe try manual instal?"
                sys.exit(2)
        else:
            print "Aborting instalation"
            sys.exit(2)

    os.system('brew update')
    os.system('brew install go')
    os.system('brew install git')
    os.system('brew install mercurial')
    success = True
    if success:
        success = os.system('go get golang.org/x/tools/cmd/godoc | go get golang.org/x/tools/cmd/vet')
        if success:
            print "Successfully installed golang"
        else:
            print "Failed to install golang"
            sys.exit(2)
    else:
        print "Failed to install golang"
        sys.exit(2)

def usage():
    print "python golangInstall.py [-u gitUserName] [-g gopath] [-h]"

def which(program):
    import os
    def is_exe(fpath):
        return os.path.isfile(fpath) and os.access(fpath, os.X_OK)

    fpath, fname = os.path.split(program)
    if fpath:
        if is_exe(program):
            return program
    else:
        for path in os.environ["PATH"].split(os.pathsep):
            path = path.strip('"')
            exe_file = os.path.join(path, program)
            if is_exe(exe_file):
                return exe_file

    return None

def query_yes_no(question, default="yes"):
    """Ask a yes/no question via raw_input() and return their answer.

    "question" is a string that is presented to the user.
    "default" is the presumed answer if the user just hits <Enter>.
        It must be "yes" (the default), "no" or None (meaning
        an answer is required of the user).

    The "answer" return value is True for "yes" or False for "no".
    """
    valid = {"yes": True, "y": True, "ye": True,
             "no": False, "n": False}
    if default is None:
        prompt = " [y/n] "
    elif default == "yes":
        prompt = " [Y/n] "
    elif default == "no":
        prompt = " [y/N] "
    else:
        raise ValueError("invalid default answer: '%s'" % default)

    while True:
        sys.stdout.write(question + prompt)
        choice = raw_input().lower()
        if default is not None and choice == '':
            return valid[default]
        elif choice in valid:
            return valid[choice]
        else:
            sys.stdout.write("Please respond with 'yes' or 'no' "
                             "(or 'y' or 'n').\n")

def append_line_to_file(line, file):
    value = str(line)
    with open(file, 'a+') as f:
        f.seek(0)
        if not any(value == x.rstrip('\r\n') for x in f):
            f.write(value + '\n')

if __name__ == "__main__":
    main(sys.argv[1:])