from django.conf import settings
from django.db import models
from jsonfield import JSONField

from api.models import UuidAuditedModel, DeisException

import logging
logger = logging.getLogger(__name__)


class Build(UuidAuditedModel):
    """
    Instance of a software build used by runtime nodes
    """

    owner = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.PROTECT)
    app = models.ForeignKey('App', on_delete=models.CASCADE)
    image = models.TextField()

    # optional fields populated by builder
    sha = models.CharField(max_length=40, blank=True)
    procfile = JSONField(default={}, blank=True)
    dockerfile = models.TextField(blank=True)

    class Meta:
        get_latest_by = 'created'
        ordering = ['-created']
        unique_together = (('app', 'uuid'),)

    @property
    def type(self):
        """Figures out what kind of build type is being deal it with"""
        if self.dockerfile:
            return 'dockerfile'
        elif self.sha:
            return 'buildpack'
        else:
            # docker image (or any sort of image) used via deis pull
            return 'image'

    @property
    def source_based(self):
        """
        Checks if a build is source (has a sha) based or not
        If True then the Build is coming from the deis builder or something that
        built from git / svn / hg / etc directly
        """
        return self.sha != ''

    @property
    def version(self):
        return 'git-{}'.format(self.sha) if self.source_based else 'latest'

    def create(self, user, *args, **kwargs):
        latest_release = self.app.release_set.latest()
        new_release = latest_release.new(
            user,
            build=self,
            config=latest_release.config,
            source_version=self.version
        )

        try:
            self.app.deploy(new_release)
            return new_release
        except Exception as e:
            if 'new_release' in locals():
                new_release.delete()
            self.delete()

            raise DeisException(str(e)) from e

    def save(self, **kwargs):
        try:
            removed = {}
            previous_build = self.app.build_set.latest()
            for proc in previous_build.procfile:
                if proc not in self.procfile:
                    # Scale proc type down to 0
                    removed[proc] = 0

            self.app.scale(self.owner, removed)
        except Build.DoesNotExist:
            pass

        return super(Build, self).save(**kwargs)

    def __str__(self):
        return "{0}-{1}".format(self.app.id, str(self.uuid)[:7])