#!/usr/bin/python3
import os
import yaml

path = lambda d, f: os.path.join(d, f)
flatten = lambda l: [item for sublist in l for item in sublist]

def help():
    print("""
Usage: calculate-dependencies <file.yaml>

Calculate dependencies from packer templates in yaml format.
Currently only get dependencies from:

* builders:
  * virtualbox-iso (1)
  * virtualbox-ovf
* provisioners:
  * file
  * shell

(1): Add all files in the `http_directory` as dependencies.
""")

def get_dependencies_virtualbox_iso_http_directory(data):
    dependencies = []
    http_directories = [builder["http_directory"] for builder in data["builders"] if builder["type"] == "virtualbox-iso"]
    for http_directory in http_directories:
        preseed_files = [path(http_directory, f) for f in os.listdir(http_directory) if os.path.isfile(path(http_directory, f))]
        dependencies.extend(preseed_files)
    return dependencies

def get_dependencies_virtualbox_ovf_source_path(data):
    dependencies = []
    source_path = [builder["source_path"] for builder in data["builders"] if builder["type"] == "virtualbox-ovf"]
    dependencies.extend(source_path)
    return dependencies

def get_dependencies_shell_scripts(data):
    dependencies = []
    scripts = [provisioner["scripts"] for provisioner in data['provisioners'] if provisioner["type"] == "shell"]
    dependencies.extend(flatten(scripts))
    return dependencies

def get_dependencies_file_source(data):
    dependencies = []
    sources = [provisioner["source"] for provisioner in data['provisioners'] if provisioner["type"] == "file"]
    for source in sources:
        if os.path.isfile(source):
            dependencies.extend(source)
        else:
            directories = [source]
            while len(directories) != 0:
                directory = directories.pop()
                for (dirpath, dirnames, filenames) in os.walk(directory):
                    dependencies.extend([path(dirpath, file) for file in filenames])
                    directories.extend(dirnames)
    return dependencies

def get_dependencies(yamlfile):
    with open(yamlfile) as file:
        data = yaml.load(file)
        dependencies = []
        dependencies.extend(get_dependencies_virtualbox_iso_http_directory(data))
        dependencies.extend(get_dependencies_virtualbox_ovf_source_path(data))
        dependencies.extend(get_dependencies_shell_scripts(data))
        dependencies.extend(get_dependencies_file_source(data))
        # make the dependencies reproducible
        dependencies = sorted(list(set(dependencies)))
        # get a string
        dependencies = " ".join(dependencies)
        return dependencies


if __name__ == '__main__':
    import sys

    if len(sys.argv) != 2:
        help()
        sys.exit(1)
    if not os.path.isfile(sys.argv[1]):
        print("File %s does not exist" % sys.argv[1])
        sys.exit(1)
    try:
        print(get_dependencies(sys.argv[1]))
    except yaml.scanner.ScannerError:
        print("Invalid yaml file")
        sys.exit(1)
    except FileNotFoundError as e:
        print(e)
        sys.exit(1)