import sys

class Formula():

    # class variables
    git_url = ''
    version = ''
    local_path = ''

    # class constructor
    def __init__(self, formula_def, formulas_dir, formulas_url):
        self.formulas_dir = formulas_dir
        self.formulas_url = formulas_url
        self.formula_def = formula_def
        self.__parse_entry()

    # sets the formula's git_url and local_path variables
    def __parse_entry(self):
        # define our function variables here
        git_url = ''
        version = ''
        local_path = ''

        # check if the formula entry is a string or a dictionary
        if isinstance(self.formula_def, dict):        
            # entry is a dictionary
            # check if the formula's name was defined
            if not 'name' in self.formula_def:
                # set the formula's name if need be
                name_partial = [k for k, v in self.formula_def.items() if v == None][0]
                self.formula_def['name'] = name_partial + '-formula'

            # check if the dictionary has a git URL defined
            if 'url' in self.formula_def:
                git_url = str(self.formula_def['url'])
            else:
                git_url = str(self.formulas_url) + str(self.formula_def['name'])
            
            # check if the git tag was defined
            if 'version' in self.formula_def:
                version = str(self.formula_def['version'])
            else:
                # this is incorrect!
                print('You must define a version tag for every formula (issue is: ' + str(self.formula_def) + ')')
                sys.exit(1)

            # put together the local
            local_path = str(self.formulas_dir) + '/' + str(self.formula_def['name'])
        else:
            # entry type is not supported
            print('One of your formula entries is not a dict (' + str(self.formula_def) + ') - please fix this.')
            sys.exit(1)

        # set the class values here
        self.git_url = git_url
        self.version = version
        self.local_path = local_path

    # checks to see if a tag to track has been defined
    def get_tracking_state(self):
        return self.version