#!/usr/bin/env python

from git import Repo
import os
import sys
import yaml

# constants
CONFIG_FILE = 'sfm.yaml'

# reads configuration and returns the dictionary
def read_config():
    f = open(CONFIG_FILE, 'r')
    conf = yaml.load(f)
    f.close()

    return conf

# makes the formulas directory if it doesn't exist
def check_formula_dir(formulas_dir):
    # check if the formulas directory is actually a directory
    if not os.path.isdir(formulas_dir):
        # check if it's a file
        if os.path.exists(formulas_dir):
            print(str(formulas_dir) + ' exists but is not a directory. Please fix this.')
            sys.exit(1)
        # create it if not
        else:
            os.makedirs(formulas_dir)

# loops through the array of repos and downloads them
def get_formulas(formulas, formulas_dir, formulas_url):
    # loop through the defined formulas
    for formula in formulas:
        git_url, local_path = parse_formula_entry(formula, formulas_dir, formulas_url)

        # check if the destination directory exists
        if os.path.exists(local_path):
            print(local_path + ' already exists, so we\'re skipping this.')
        else:
            print('Downloading ' + git_url + ' into ' + local_path)
            # clone git repo
            Repo.clone_from(git_url, local_path)

# parses a formula entry, and then returns the target git URL and the destination for the clone
def parse_formula_entry(formula, formulas_dir, formulas_url):
    # define our variables to be returned
    git_url = ''
    local_path = ''

    # check if the formula entry is a string or a dictionary
    if isinstance(formula, dict):
        # entry is a dictionary
        git_url = str(formula['url'])
        local_path = str(formulas_dir) + '/' + str(formula['name'])
    elif isinstance(formula, str):
        # entry is a string
        git_url = str(formulas_url) + str(formula) + '-formula'
        local_path = str(formulas_dir) + '/' + str(formula) + '-formula'
    else:
        # entry type is not supported
        print('One of your entries is not a dict or a string (' + str(formula) + ') - please fix this.')
        sys.exit(1)

    # return the values here
    return git_url, local_path

# purge un-managed formulas
def clean_formulas(conf):
    if conf['purge_formulas']:
        print('Cleaning out unmanaged formulas')
        
    else:
        print('Not cleaning out unmanaged formulas')

# main program
def main():
    # read configuration settings
    conf = read_config()

    # make sure the formulas directory exists
    check_formula_dir(conf['formulas_dir'])

    # do the formula stuff
    get_formulas(conf['formulas'], conf['formulas_dir'], conf['formulas_url'])

    # clean unmanaged formulas
    #clean_formulas(conf)

# run main
main()