# Copyright 2020 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import base64
import json
import os
import shutil
import sys

import common

BLINK_TOOLS_DIR = os.path.join(common.SRC_DIR, 'third_party', 'blink', 'tools')
WEB_TESTS_DIR = os.path.join(BLINK_TOOLS_DIR, os.pardir, 'web_tests')

if BLINK_TOOLS_DIR not in sys.path:
    sys.path.append(BLINK_TOOLS_DIR)

from blinkpy.common.host import Host
from blinkpy.web_tests.models import test_failures

class BaseWptScriptAdapter(common.BaseIsolatedScriptArgsAdapter):
    """The base class for script adapters that use wptrunner to execute web
    platform tests. This contains any code shared between these scripts, such
    as integrating output with the results viewer. Subclasses contain other
    (usually platform-specific) logic."""

    def __init__(self):
        super(BaseWptScriptAdapter, self).__init__()
        host = Host()
        self.port = host.port_factory.get()

    def generate_test_output_args(self, output):
        return ['--log-chromium', output]

    def generate_sharding_args(self, total_shards, shard_index):
        return ['--total-chunks=%d' % total_shards,
                # shard_index is 0-based but WPT's this-chunk to be 1-based
                '--this-chunk=%d' % (shard_index + 1)]

    def do_post_test_run_tasks(self):
        # Move json results into layout-test-results directory
        results_dir = os.path.dirname(self.options.isolated_script_test_output)
        layout_test_results = os.path.join(results_dir, 'layout-test-results')
        if os.path.exists(layout_test_results):
            shutil.rmtree(layout_test_results)
        os.mkdir(layout_test_results)

        # Perform post-processing of wptrunner output
        self.process_wptrunner_output()

        shutil.copyfile(self.options.isolated_script_test_output,
                        os.path.join(layout_test_results, 'full_results.json'))
        # create full_results_jsonp.js file which is used to
        # load results into the results viewer
        with open(self.options.isolated_script_test_output, 'r') \
            as full_results, \
            open(os.path.join(
                layout_test_results, 'full_results_jsonp.js'), 'w') \
                as json_js:
            json_js.write('ADD_FULL_RESULTS(%s);' % full_results.read())
        # copy layout test results viewer to layout-test-results directory
        shutil.copyfile(
            os.path.join(WEB_TESTS_DIR, 'fast', 'harness', 'results.html'),
            os.path.join(layout_test_results, 'results.html'))

    def process_wptrunner_output(self):
        """Post-process the output generated by wptrunner.

        This output contains a single large json file containing the raw content
        or artifacts which need to be extracted into their own files and removed
        from the json file (to avoid duplication)."""
        output_json = json.load(
            open(self.options.isolated_script_test_output, "r"))
        test_json = output_json["tests"]
        results_dir = os.path.dirname(self.options.isolated_script_test_output)
        self._process_test_leaves(results_dir, output_json["path_delimiter"],
                                  test_json, "")
        # Write output_json back to the same file after modifying it in memory
        with open(self.options.isolated_script_test_output, "w") as output_file:
            json.dump(output_json, output_file)

    def _process_test_leaves(self, results_dir, delim, root_node, path_so_far):
        """Finds and processes each test leaf below the specified root.

        This will recursively traverse the trie of results in the json output,
        keeping track of the path to each test and identifying leaves by the
        presence of certain attributes.

        Args:
            results_dir: str path to the dir that results are stored
            delim: str delimiter to be used for test names
            root_node: dict representing the root of the trie we're currently
                looking at
            path_so_far: str the path to the current root_node in the trie
        """
        if "actual" in root_node:
            # Found a leaf, process it
            if "artifacts" not in root_node:
                return
            log_artifact = root_node["artifacts"].pop("log", None)
            if log_artifact:
                artifact_subpath = self._write_log_artifact(
                    results_dir, path_so_far, log_artifact)
                root_node["artifacts"]["actual_text"] = [artifact_subpath]

            screenshot_artifact = root_node["artifacts"].pop("screenshots",
                                                             None)
            if screenshot_artifact:
                screenshot_paths_dict = self._write_screenshot_artifact(
                    results_dir, path_so_far, screenshot_artifact)
                for screenshot_key, path in screenshot_paths_dict.items():
                    root_node["artifacts"][screenshot_key] = [path]

            return

        # We're not at a leaf node, continue traversing the trie.
        for key in root_node:
            # Append the key to the path, separated by the delimiter. However if
            # the path is empty, skip the delimiter to avoid a leading slash in
            # the path.
            new_path = path_so_far + delim + key if path_so_far else key
            self._process_test_leaves(results_dir, delim, root_node[key],
                                      new_path)

    def _write_log_artifact(self, results_dir, test_name, log_artifact):
        """Writes a log artifact to disk.

        The log artifact contains all the output of a test. It gets written to
        the -actual.txt file for the test.

        Args:
            results_dir: str path to the directory that results live in
            test_name: str name of the test that this artifact is for
            log_artifact: list of strings, the log entries for this test from
                the json output.

        Returns:
            string path to the artifact file that the log was written to,
            relative to the directory that the original output is located.
        """
        log_artifact_sub_path = (
            os.path.join("layout-test-results",
                         self.port.output_filename(
                             test_name, test_failures.FILENAME_SUFFIX_ACTUAL,
                             ".txt"))
        )
        log_artifact_full_path = os.path.join(results_dir,
                                              log_artifact_sub_path)
        if not os.path.exists(os.path.dirname(log_artifact_full_path)):
            os.makedirs(os.path.dirname(log_artifact_full_path))
        with open(log_artifact_full_path, "w") as artifact_file:
            artifact_file.write("\n".join(log_artifact).encode("utf-8"))

        return log_artifact_sub_path

    def _write_screenshot_artifact(self, results_dir, test_name,
                                   screenshot_artifact):
        """Write screenshot artifact to disk.

        The screenshot artifact is a list of strings, each of which has the
        format <url>:<base64-encoded PNG>. Each url-png pair is a screenshot of
        either the test, or one of its refs. We can identify which screenshot is
        for the test by comparing the url piece to the test name.

        Args:
           results_dir: str path to the directory that results live in
           test:name str name of the test that this artifact is for
           screenshot_artifact: list of strings, each being a url-png pair as
               described above.

        Returns:
             A dict mapping the screenshot key (ie: actual, expected) to the
             path of the file for that screenshot
        """
        result={}
        for screenshot_pair in screenshot_artifact:
            screenshot_split = screenshot_pair.split(":")
            url = screenshot_split[0]
            # The url produced by wptrunner will have a leading / which we trim
            # away for easier comparison to the test_name below.
            if url.startswith("/"):
                url = url[1:]
            image_bytes = base64.b64decode(screenshot_split[1].strip())

            screenshot_key = "expected_image"
            file_suffix = test_failures.FILENAME_SUFFIX_EXPECTED
            if test_name == url:
                screenshot_key = "actual_image"
                file_suffix = test_failures.FILENAME_SUFFIX_ACTUAL

            screenshot_sub_path = (
                os.path.join("layout-test-results",
                             self.port.output_filename(
                                 test_name, file_suffix, ".png"))
            )
            result[screenshot_key] = screenshot_sub_path

            screenshot_full_path = os.path.join(results_dir,screenshot_sub_path)
            if not os.path.exists(os.path.dirname(screenshot_full_path)):
                os.makedirs(os.path.dirname(screenshot_full_path))
            # Note: we are writing raw bytes to this file
            with open(screenshot_full_path, "wb") as artifact_file:
                artifact_file.write(image_bytes)
        return result