# -*- coding: utf-8 -*-
# Copyright 2019 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""The payload API is the entry point for payload functionality."""

from __future__ import print_function

from copy import deepcopy
import sys

from chromite.lib import chroot_util
from chromite.lib.paygen import gspaths
from chromite.lib.paygen import paygen_payload_lib

from chromite.api.gen.chromiumos import common_pb2
from chromite.api.gen.chromite.api import payload_pb2


assert sys.version_info >= (3, 6), 'This module requires Python 3.6+'


class Error(Exception):
  """Base module error."""


class ImageTypeUnknownError(Error):
  """An error raised when image type is unknown."""


class ImageMismatchError(Error):
  """An error raised when src and tgt aren't compatible."""


class PayloadConfig(object):
  """Value object to hold the GeneratePayload configuration options."""

  def __init__(self, tgt_image=None, src_image=None,
               dest_bucket=None, verify=True, keyset=None):
    """Init method, sets up all the paths and configuration.

    Args:
      tgt_image (UnsignedImage or SignedImage): Proto for destination image.
      src_image (UnsignedImage or SignedImage or None): Proto for source image.
      dest_bucket (str): Destination bucket to place the final artifacts in.
      verify (bool): If delta is made, verify the integrity of the payload.
      keyset (str): The key to sign the image with.
    """

    # Set when we call GeneratePayload on this object.
    self.paygen = None
    self.tgt_image = tgt_image
    self.src_image = src_image
    self.dest_bucket = dest_bucket
    self.verify = verify
    self.keyset = keyset
    self.delta_type = 'delta' if self.src_image else 'full'
    self.image_type = _ImageTypeToStr(tgt_image.image_type)

    # This block ensures that we have paths to the correct perm of images.
    if self.delta_type == 'delta':
      if isinstance(self.tgt_image, payload_pb2.UnsignedImage):
        tgt_image_path = _GenUnsignedGSPath(self.tgt_image, self.image_type)
        src_image_path = _GenUnsignedGSPath(self.src_image, self.image_type)

      elif isinstance(self.tgt_image, payload_pb2.SignedImage):
        tgt_image_path = _GenSignedGSPath(self.tgt_image, self.image_type)
        src_image_path = _GenSignedGSPath(self.src_image, self.image_type)

    elif self.delta_type == 'full':
      tgt_image_path = _GenUnsignedGSPath(self.tgt_image, self.image_type)
      src_image_path = None

    # Set your output location.
    payload_build = deepcopy(tgt_image_path.build)
    payload_build.bucket = dest_bucket
    payload_output_uri = gspaths.ChromeosReleases.PayloadUri(
        build=payload_build, random_str=None, key=self.keyset,
        src_version=src_image_path.build.version if src_image else None,
    )

    self.payload = gspaths.Payload(
        tgt_image=tgt_image_path, src_image=src_image_path,
        uri=payload_output_uri)


  def GeneratePayload(self):
    """Do payload generation (& maybe sign) on Google Storage cros images.

    Returns:
      True if successful, raises otherwise.
    """
    should_sign = True if self.keyset != '' else False

    with chroot_util.TempDirInChroot() as temp_dir:
      self.paygen = paygen_payload_lib.PaygenPayload(self.payload, temp_dir,
                                                     sign=should_sign,
                                                     verify=self.verify)
      self.paygen.Run()

    return True


class GeneratePayloadResult(object):
  """Value object to report GeneratePayload results."""

  def __init__(self, return_code):
    """Initialize a GeneratePayloadResult.

    Args:
      return_code (bool): The return code of the GeneratePayload operation.
    """
    self.success = return_code == 0


def _ImageTypeToStr(image_type_n):
  """The numeral image type enum in proto to lowercase string."""
  return common_pb2.ImageType.Name(image_type_n).lower()


def _GenSignedGSPath(image, image_type):
  """Take a SignedImage_pb2 and return a gspaths.Image.

  Args:
    image (SignedImage_pb2): The build to create the gspath from.
    image_type (string): The image type, either "recovery" or "base".

  Returns:
    A gspaths.Image instance.
  """
  build = gspaths.Build(board=image.build.build_target.name,
                        version=image.build.version,
                        channel=image.build.channel,
                        bucket=image.build.bucket)

  build_uri = gspaths.ChromeosReleases.ImageUri(
      build, image.key, image_type)

  build.uri = build_uri

  return gspaths.Image(build=build,
                       image_type=image_type,
                       uri=build_uri)


def _GenUnsignedGSPath(image, image_type):
  """Take a UnsignedImage_pb2 and return a gspaths.UnsignedImageArchive.

  Args:
    image (UnsignedImage_pb2): The build to create the gspath from.
    image_type (string): The image type, either "recovery" or "test".

  Returns:
    A gspaths.UnsignedImageArchive instance.
  """
  build = gspaths.Build(board=image.build.build_target.name,
                        version=image.build.version,
                        channel=image.build.channel,
                        bucket=image.build.bucket)

  build_uri = gspaths.ChromeosReleases.UnsignedImageUri(
      build, image.milestone, image_type)

  build.uri = build_uri

  return gspaths.UnsignedImageArchive(build=build,
                                      milestone=image.milestone,
                                      image_type=image_type,
                                      uri=build_uri)