#!/usr/bin/env dart
// Copyright (c) 2018, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

// Compare the old and new test results and list tests that pass the filters.
// The output contains additional details in the verbose mode. There is a human
// readable mode that explains the results and how they changed.

import 'dart:collection';
import 'dart:io';

import 'package:args/args.dart';

import 'results.dart';

class Result {
  final String configuration;
  final String name;
  final String outcome;
  final String expectation;
  final bool matches;
  final bool flaked;

  Result(this.configuration, this.name, this.outcome, this.expectation,
      this.matches, this.flaked);

  Result.fromMap(Map<String, dynamic> map, Map<String, dynamic> flakinessData)
      : configuration = map["configuration"],
        name = map["name"],
        outcome = map["result"],
        expectation = map["expected"],
        matches = map["matches"],
        flaked = flakinessData != null &&
            flakinessData["outcomes"].contains(map["result"]);

  String get key => "$configuration:$name";
}

class Event {
  final Result before;
  final Result after;
  final Result approved;

  Event(this.before, this.after, this.approved);

  bool get isNew => before == null;
  bool get isNewPassing => before == null && after.matches;
  bool get isNewFailing => before == null && !after.matches;
  bool get changed => !unchanged;
  bool get unchanged => before != null && before.outcome == after.outcome;
  bool get isApproved => approved != null && approved.outcome == after.outcome;
  bool get isUnapproved => !isApproved;
  bool get remainedPassing => before.matches && after.matches;
  bool get remainedFailing => !before.matches && !after.matches;
  bool get flaked => after.flaked;
  bool get fixed => !before.matches && after.matches;
  bool get broke => before.matches && !after.matches;

  String get description {
    if (isNewPassing) {
      return "is new and succeeded";
    } else if (isNewFailing) {
      return "is new and failed";
    } else if (remainedPassing) {
      return "succeeded again";
    } else if (remainedFailing) {
      return "failed again";
    } else if (fixed) {
      return "was fixed";
    } else if (broke) {
      return "broke";
    } else {
      throw new Exception("Unreachable");
    }
  }
}

bool firstSection = true;

bool search(
    String description,
    String searchForStatus,
    String searchForApproval,
    List<Event> events,
    ArgResults options,
    Map<String, Map<String, dynamic>> logs,
    List<String> logSection) {
  bool judgement = false;
  bool beganSection = false;
  int count = options["count"] != null ? int.parse(options["count"]) : null;
  final configurations =
      events.map((event) => event.after.configuration).toSet();
  for (final event in events) {
    if (searchForStatus == "passing" &&
        (event.after.flaked || !event.after.matches)) {
      continue;
    }
    if (searchForStatus == "flaky" && !event.after.flaked) {
      continue;
    }
    if (searchForStatus == "failing" &&
        (event.after.flaked || event.after.matches)) {
      continue;
    }
    if (searchForApproval == "approved" && !event.isApproved) {
      continue;
    }
    if (searchForApproval == "unapproved" && !event.isUnapproved) {
      continue;
    }
    if (options["unchanged"] && !event.unchanged) continue;
    if (options["changed"] && !event.changed) continue;
    if (!beganSection) {
      if (options["human"] && !options["logs-only"]) {
        if (!firstSection) {
          print("");
        }
        firstSection = false;
        print("$description\n");
      }
    }
    beganSection = true;
    final before = event.before;
    final after = event.after;
    // The --flaky option is used to get a list of tests to deflake within a
    // single named configuration. Therefore we can't right now always emit
    // the configuration name, so only do it if there's more than one in the
    // results being compared (that won't happen during deflaking.
    final name =
        configurations.length == 1 ? event.after.name : event.after.key;
    if (!after.flaked && !after.matches) {
      judgement = true;
    }
    if (count != null) {
      if (--count <= 0) {
        if (options["human"]) {
          print("(And more)");
        }
        break;
      }
    }
    String output;
    if (options["verbose"]) {
      if (options["human"]) {
        String expect = after.matches ? "" : ", expected ${after.expectation}";
        if (before == null || before.outcome == after.outcome) {
          output = "$name ${event.description} "
              "(${event.after.outcome}${expect})";
        } else {
          output = "$name ${event.description} "
              "(${event.before?.outcome} -> ${event.after.outcome}${expect})";
        }
      } else {
        output = "$name ${before?.outcome} ${after.outcome} "
            "${before?.expectation} ${after.expectation} "
            "${before?.matches} ${after.matches} "
            "${before?.flaked} ${after.flaked}";
      }
    } else {
      output = name;
    }
    if (logs != null) {
      final log = logs[event.after.key];
      final bar = '=' * (output.length + 2);
      if (log != null) {
        logSection?.add("\n\n/$bar\\\n| $output |\n\\$bar/\n\n${log["log"]}");
      }
    }
    if (!options["logs-only"]) {
      print(output);
    }
  }

  return judgement;
}

main(List<String> args) async {
  final parser = new ArgParser();
  parser.addFlag("approved",
      abbr: 'A', negatable: false, help: "Show approved tests.");
  parser.addFlag("changed",
      abbr: 'c',
      negatable: false,
      help: "Show only tests that changed results.");
  parser.addOption("count",
      abbr: "C",
      help: "Upper limit on how many tests to report in each section");
  parser.addFlag("failing",
      abbr: 'f', negatable: false, help: "Show failing tests.");
  parser.addOption("flakiness-data",
      abbr: 'd', help: "File containing flakiness data");
  parser.addFlag("judgement",
      abbr: 'j',
      negatable: false,
      help: "Exit 1 only if any of the filtered results failed.");
  parser.addFlag("flaky",
      abbr: 'F', negatable: false, help: "Show flaky tests.");
  parser.addFlag("help", help: "Show the program usage.", negatable: false);
  parser.addFlag("human",
      abbr: "h",
      help: "Prove you can't read machine readable output.",
      negatable: false);
  parser.addFlag("passing",
      abbr: 'p', negatable: false, help: "Show passing tests.");
  parser.addFlag("unapproved",
      abbr: 'U', negatable: false, help: "Show unapproved tests.");
  parser.addFlag("unchanged",
      abbr: 'u',
      negatable: false,
      help: "Show only tests with unchanged results.");
  parser.addFlag("verbose",
      abbr: "v",
      help: "Show the old and new result for each test",
      negatable: false);
  parser.addOption("logs",
      abbr: "l", help: "Path to file holding logs of failing and flaky tests.");
  parser.addFlag("logs-only",
      help: "Only print logs of failing and flaky tests, no other output",
      negatable: false);

  final options = parser.parse(args);
  if (options["help"]) {
    print("""
Usage: compare_results.dart [OPTION]... BEFORE AFTER [APPROVED]
Compare the old and new test results and list tests that pass the filters.
Three-way compare with the approved results if provided.
All tests are listed if no filters are given.

The options are as follows:

${parser.usage}""");
    return;
  }

  if (options["changed"] && options["unchanged"]) {
    print(
        "error: The options --changed and --unchanged are mutually exclusive");
    exitCode = 2;
    return;
  }

  final parameters = options.rest;
  if (parameters.length != 2 && parameters.length != 3) {
    print("error: Expected two or three parameters "
        "(results before, results after, and (optionally) approved results)");
    exitCode = 2;
    return;
  }

  // Load the input and the flakiness data if specified.
  final before = await loadResultsMap(parameters[0]);
  final after = await loadResultsMap(parameters[1]);
  final approved = 3 <= parameters.length
      ? await loadResultsMap(parameters[2])
      : <String, Map<String, dynamic>>{};
  final logs = options['logs'] == null
      ? <String, Map<String, dynamic>>{}
      : await loadResultsMap(options['logs']);
  final flakinessData = options["flakiness-data"] != null
      ? await loadResultsMap(options["flakiness-data"])
      : <String, Map<String, dynamic>>{};

  // The names of every test that has a data point in the new data set.
  final names = new SplayTreeSet<String>.from(after.keys);

  final events = <Event>[];
  for (final name in names) {
    final mapBefore = before[name];
    final mapAfter = after[name];
    final mapApproved = approved[name];
    final resultBefore = mapBefore != null
        ? new Result.fromMap(mapBefore, flakinessData[name])
        : null;
    final resultAfter = new Result.fromMap(mapAfter, flakinessData[name]);
    final resultApproved = mapApproved != null && mapApproved["result"] != null
        ? new Result.fromMap(mapApproved, flakinessData[name])
        : null;
    final event = new Event(resultBefore, resultAfter, resultApproved);
    events.add(event);
  }

  final filterDescriptions = {
    "passing": {
      "unchanged": "continued to pass",
      "changed": "began passing",
      null: "passed",
    },
    "flaky": {
      "unchanged": "are known to flake but didn't",
      "changed": "flaked",
      null: "are known to flake",
    },
    "failing": {
      "unchanged": "continued to fail",
      "changed": "began failing",
      null: "failed",
    },
    null: {
      "unchanged": "had the same result",
      "changed": "changed result",
      null: "ran",
    },
  };

  final searchForStatuses =
      ["passing", "flaky", "failing"].where((option) => options[option]);

  final approvalDescriptions = {
    "passing": {
      "approved": " (approved)",
      "unapproved": " (should be approved)",
      null: "",
    },
    "flaky": {
      "approved": " (approved result)",
      "unapproved": " (unapproved result)",
      null: "",
    },
    "failing": {
      "approved": " (approved)",
      "unapproved": " (needs approval)",
      null: "",
    },
    null: {
      "approved": " (approved)",
      "unapproved": " (needs approval)",
      null: "",
    },
  };

  final searchForApprovals =
      ["approved", "unapproved"].where((option) => options[option]);

  // Report tests matching the filters.
  final logSection = <String>[];
  bool judgement = false;
  for (final searchForStatus
      in searchForStatuses.isNotEmpty ? searchForStatuses : <String>[null]) {
    for (final searchForApproval in searchForApprovals.isNotEmpty
        ? searchForApprovals
        : <String>[null]) {
      final searchForChanged = options["unchanged"]
          ? "unchanged"
          : options["changed"] ? "changed" : null;
      final aboutStatus = filterDescriptions[searchForStatus][searchForChanged];
      final aboutApproval =
          approvalDescriptions[searchForStatus][searchForApproval];
      final sectionHeader = "The following tests $aboutStatus$aboutApproval:";
      final logSectionArg =
          searchForStatus == "failing" || searchForStatus == "flaky"
              ? logSection
              : null;
      bool possibleJudgement = search(sectionHeader, searchForStatus,
          searchForApproval, events, options, logs, logSectionArg);
      if ((searchForStatus == null || searchForStatus == "failing") &&
          (searchForApproval == null || searchForApproval == "unapproved")) {
        judgement = possibleJudgement;
      }
    }
  }

  if (logSection.isNotEmpty) {
    print(logSection.join());
  }
  // Exit 1 only if --judgement and any test failed.
  if (options["judgement"]) {
    if (options["human"] && !options["logs-only"] && !firstSection) {
      print("");
    }
    String oldNew =
        options["unchanged"] ? "old " : options["changed"] ? "new " : "";
    if (judgement) {
      if (options["human"] && !options["logs-only"]) {
        print("There were ${oldNew}test failures.");
      }
      exitCode = 1;
    } else {
      if (options["human"] && !options["logs-only"]) {
        print("No ${oldNew}test failures were found.");
      }
    }
  }
}