from .service import Service

def sort_service_dicts(services):
    # Sort in dependency order
    def cmp(x, y):
        x_deps_y = y['name'] in x.get('links', [])
        y_deps_x = x['name'] in y.get('links', [])
        if x_deps_y and not y_deps_x:
            return 1
        elif y_deps_x and not x_deps_y:
            return -1
        return 0
    return sorted(services, cmp=cmp)

class Project(object):
    """
    A collection of services.
    """
    def __init__(self, name, services, client):
        self.name = name
        self.services = services
        self.client = client

    @classmethod
    def from_dicts(cls, name, service_dicts, client):
        """
        Construct a ServiceCollection from a list of dicts representing services.
        """
        project = cls(name, [], client)
        for service_dict in sort_service_dicts(service_dicts):
            # Reference links by object
            links = []
            if 'links' in service_dict:
                for service_name in service_dict.get('links', []):
                    links.append(project.get_service(service_name))
                del service_dict['links']
            project.services.append(Service(client=client, project=name, links=links, **service_dict))
        return project

    @classmethod
    def from_config(cls, name, config, client):
        dicts = []
        for service_name, service in config.items():
            service['name'] = service_name
            dicts.append(service)
        return cls.from_dicts(name, dicts, client)

    def get_service(self, name):
        """
        Retrieve a service by name. Raises NoSuchService
        if the named service does not exist.
        """
        for service in self.services:
            if service.name == name:
                return service

        raise NoSuchService(name)

    def get_services(self, service_names=None):
        """
        Returns a list of this project's services filtered
        by the provided list of names, or all services if
        service_names is None or [].

        Preserves the original order of self.services.

        Raises NoSuchService if any of the named services
        do not exist.
        """
        if service_names is None or len(service_names) == 0:
            return self.services
        else:
            unsorted = [self.get_service(name) for name in service_names]
            return [s for s in self.services if s in unsorted]

    def create_containers(self, service_names=None):
        """
        For each service, creates a container if there are none.
        """
        for service in self.get_services(service_names):
            if len(service.containers(stopped=True)) == 0:
                service.create_container()

    def start(self, service_names=None, **options):
        for service in self.get_services(service_names):
            service.start(**options)

    def stop(self, service_names=None, **options):
        for service in self.get_services(service_names):
            service.stop(**options)

    def kill(self, service_names=None, **options):
        for service in self.get_services(service_names):
            service.kill(**options)

    def build(self, service_names=None, **options):
        for service in self.get_services(service_names):
            if service.can_be_built():
                service.build(**options)
            else:
                log.info('%s uses an image, skipping')

    def remove_stopped(self, service_names=None, **options):
        for service in self.get_services(service_names):
            service.remove_stopped(**options)

    def containers(self, service_names=None, *args, **kwargs):
        l = []
        for service in self.get_services(service_names):
            for container in service.containers(*args, **kwargs):
                l.append(container)
        return l


class NoSuchService(Exception):
    def __init__(self, name):
        self.name = name
        self.msg = "No such service: %s" % self.name

    def __str__(self):
        return self.msg