// run_chromium_perf is an application that runs the specified benchmark over CT's
// webpage archives.
package main

import (
	"context"
	"errors"
	"flag"
	"fmt"
	"io/ioutil"
	"os"
	"path"
	"path/filepath"
	"strings"
	"sync"
	"time"

	"go.skia.org/infra/ct/go/adb"
	"go.skia.org/infra/ct/go/util"
	"go.skia.org/infra/ct/go/worker_scripts/worker_common"
	"go.skia.org/infra/go/exec"
	"go.skia.org/infra/go/skerr"
	"go.skia.org/infra/go/sklog"
	skutil "go.skia.org/infra/go/util"
)

const (
	// The number of goroutines that will run in parallel to run benchmarks.
	WORKER_POOL_SIZE = 5
	// The number of allowed benchmark timeouts in a row before the worker
	// script fails.
	MAX_ALLOWED_SEQUENTIAL_TIMEOUTS = 20
)

var (
	startRange                = flag.Int("start_range", 1, "The number this worker will run benchmarks from.")
	num                       = flag.Int("num", 100, "The total number of benchmarks to run starting from the start_range.")
	pagesetType               = flag.String("pageset_type", util.PAGESET_TYPE_MOBILE_10k, "The type of pagesets to create from the Alexa CSV list. Eg: 10k, Mobile10k, All.")
	chromiumBuildNoPatch      = flag.String("chromium_build_nopatch", "", "The chromium build to use for the nopatch run.")
	chromiumBuildWithPatch    = flag.String("chromium_build_withpatch", "", "The chromium build to use for the withpatch run.")
	runID                     = flag.String("run_id", "", "The unique run id (typically requester + timestamp).")
	benchmarkName             = flag.String("benchmark_name", "", "The telemetry benchmark to run on this worker.")
	benchmarkExtraArgs        = flag.String("benchmark_extra_args", "", "The extra arguments that are passed to the specified benchmark.")
	browserExtraArgsNoPatch   = flag.String("browser_extra_args_nopatch", "", "The extra arguments that are passed to the browser while running the benchmark during the nopatch run.")
	browserExtraArgsWithPatch = flag.String("browser_extra_args_withpatch", "", "The extra arguments that are passed to the browser while running the benchmark during the withpatch run.")
	repeatBenchmark           = flag.Int("repeat_benchmark", 3, "The number of times the benchmark should be repeated. For skpicture_printer benchmark this value is always 1.")
	runInParallel             = flag.Bool("run_in_parallel", false, "Run the benchmark by bringing up multiple chrome instances in parallel.")
	targetPlatform            = flag.String("target_platform", util.PLATFORM_ANDROID, "The platform the benchmark will run on (Android / Linux).")
	chromeCleanerTimer        = flag.Duration("cleaner_timer", 15*time.Minute, "How often all chrome processes will be killed on this worker.")
	valueColumnName           = flag.String("value_column_name", "", "Which column's entries to use as field values when combining CSVs.")
)

func runChromiumPerf() error {
	ctx := context.Background()
	httpClient, err := worker_common.Init(ctx, false /* useDepotTools */)
	if err != nil {
		return skerr.Wrap(err)
	}
	if !*worker_common.Local {
		defer util.CleanTmpDir()
	}
	defer util.TimeTrack(time.Now(), "Running Chromium Perf")
	defer sklog.Flush()

	// Validate required arguments.
	if *chromiumBuildNoPatch == "" {
		return errors.New("Must specify --chromium_build_nopatch")
	}
	if *chromiumBuildWithPatch == "" {
		return errors.New("Must specify --chromium_build_withpatch")
	}
	if *runID == "" {
		return errors.New("Must specify --run_id")
	}
	if *benchmarkName == "" {
		return errors.New("Must specify --benchmark_name")
	}

	// Use defaults.
	if *valueColumnName == "" {
		*valueColumnName = util.DEFAULT_VALUE_COLUMN_NAME
	}

	// Instantiate GcsUtil object.
	gs, err := util.NewGcsUtil(httpClient)
	if err != nil {
		return err
	}

	tmpDir, err := ioutil.TempDir("", "patches")
	remotePatchesDir := path.Join(util.ChromiumPerfRunsStorageDir, *runID)

	// Download the custom webpages for this run from Google storage.
	customWebpagesName := *runID + ".custom_webpages.csv"
	if _, err := util.DownloadPatch(filepath.Join(tmpDir, customWebpagesName), path.Join(remotePatchesDir, customWebpagesName), gs); err != nil {
		return fmt.Errorf("Could not download %s: %s", customWebpagesName, err)
	}
	customWebpages, err := util.GetCustomPages(filepath.Join(tmpDir, customWebpagesName))
	if err != nil {
		return fmt.Errorf("Could not read custom webpages file %s: %s", customWebpagesName, err)
	}
	if len(customWebpages) > 0 {
		customWebpages = util.GetCustomPagesWithinRange(*startRange, *num, customWebpages)
	}

	chromiumBuilds := []string{*chromiumBuildNoPatch}
	// No point downloading the same build twice. Download only if builds are different.
	if *chromiumBuildNoPatch != *chromiumBuildWithPatch {
		chromiumBuilds = append(chromiumBuilds, *chromiumBuildWithPatch)
	}
	// Download the specified chromium builds.
	for _, chromiumBuild := range chromiumBuilds {
		if err := gs.DownloadChromiumBuild(chromiumBuild); err != nil {
			return err
		}
		//Delete the chromium build to save space when we are done.
		defer skutil.RemoveAll(filepath.Join(util.ChromiumBuildsDir, chromiumBuild))
	}

	chromiumBinaryName := util.BINARY_CHROME
	if *targetPlatform == util.PLATFORM_WINDOWS {
		chromiumBinaryName = util.BINARY_CHROME_WINDOWS
	} else if *targetPlatform == util.PLATFORM_ANDROID {
		chromiumBinaryName = util.ApkName
	}
	chromiumBinaryNoPatch := filepath.Join(util.ChromiumBuildsDir, *chromiumBuildNoPatch, chromiumBinaryName)
	chromiumBinaryWithPatch := filepath.Join(util.ChromiumBuildsDir, *chromiumBuildWithPatch, chromiumBinaryName)

	var pathToPagesets string
	if len(customWebpages) > 0 {
		pathToPagesets = filepath.Join(util.PagesetsDir, "custom")
		if err := util.CreateCustomPagesets(customWebpages, pathToPagesets, *targetPlatform); err != nil {
			return err
		}
	} else {
		// Download pagesets if they do not exist locally.
		pathToPagesets = filepath.Join(util.PagesetsDir, *pagesetType)
		if _, err := gs.DownloadSwarmingArtifacts(pathToPagesets, util.PAGESETS_DIR_NAME, *pagesetType, *startRange, *num); err != nil {
			return err
		}
	}
	defer skutil.RemoveAll(pathToPagesets)

	if !strings.Contains(*benchmarkExtraArgs, util.USE_LIVE_SITES_FLAGS) {
		// Download archives if they do not exist locally.
		pathToArchives := filepath.Join(util.WebArchivesDir, *pagesetType)
		if _, err := gs.DownloadSwarmingArtifacts(pathToArchives, util.WEB_ARCHIVES_DIR_NAME, *pagesetType, *startRange, *num); err != nil {
			return err
		}
		defer skutil.RemoveAll(pathToArchives)
	}

	// Establish nopatch output paths.
	runIDNoPatch := fmt.Sprintf("%s-nopatch", *runID)
	localOutputDirNoPatch := filepath.Join(util.StorageDir, util.BenchmarkRunsDir, runIDNoPatch)
	skutil.RemoveAll(localOutputDirNoPatch)
	util.MkdirAll(localOutputDirNoPatch, 0700)
	defer skutil.RemoveAll(localOutputDirNoPatch)
	remoteDirNoPatch := path.Join(util.BenchmarkRunsStorageDir, runIDNoPatch)

	// Establish withpatch output paths.
	runIDWithPatch := fmt.Sprintf("%s-withpatch", *runID)
	localOutputDirWithPatch := filepath.Join(util.StorageDir, util.BenchmarkRunsDir, runIDWithPatch)
	skutil.RemoveAll(localOutputDirWithPatch)
	util.MkdirAll(localOutputDirWithPatch, 0700)
	defer skutil.RemoveAll(localOutputDirWithPatch)
	remoteDirWithPatch := path.Join(util.BenchmarkRunsStorageDir, runIDWithPatch)

	// Construct path to the ct_run_benchmark python script.
	pathToPyFiles, err := util.GetPathToPyFiles(*worker_common.Local)
	if err != nil {
		return fmt.Errorf("Could not get path to py files: %s", err)
	}

	fileInfos, err := ioutil.ReadDir(pathToPagesets)
	if err != nil {
		return fmt.Errorf("Unable to read the pagesets dir %s: %s", pathToPagesets, err)
	}

	numWorkers := WORKER_POOL_SIZE
	if *targetPlatform == util.PLATFORM_ANDROID || !*runInParallel {
		// Do not run page sets in parallel if the target platform is Android.
		// This is because the nopatch/withpatch APK needs to be installed prior to
		// each run and this will interfere with the parallel runs. Instead of trying
		// to find a complicated solution to this, it makes sense for Android to
		// continue to be serial because it will help guard against
		// crashes/flakiness/inconsistencies which are more prevalent in mobile runs.
		numWorkers = 1
		sklog.Info("===== Going to run the task serially =====")
	} else {
		sklog.Info("===== Going to run the task with parallel chrome processes =====")
	}

	// Create channel that contains all pageset file names. This channel will
	// be consumed by the worker pool.
	pagesetRequests := util.GetClosedChannelOfPagesets(fileInfos)

	var wg sync.WaitGroup
	// Use a RWMutex for the chromeProcessesCleaner goroutine to communicate to
	// the workers (acting as "readers") when it wants to be the "writer" and
	// kill all zombie chrome processes.
	var mutex sync.RWMutex

	timeoutTracker := util.TimeoutTracker{}

	// Loop through workers in the worker pool.
	for i := 0; i < numWorkers; i++ {
		// Increment the WaitGroup counter.
		wg.Add(1)

		// Create and run a goroutine closure that captures SKPs.
		go func() {
			// Decrement the WaitGroup counter when the goroutine completes.
			defer wg.Done()

			for pagesetName := range pagesetRequests {

				mutex.RLock()
				_, noPatchErr := util.RunBenchmark(ctx, pagesetName, pathToPagesets, pathToPyFiles, localOutputDirNoPatch, chromiumBinaryNoPatch, runIDNoPatch, *browserExtraArgsNoPatch, *benchmarkName, *targetPlatform, *benchmarkExtraArgs, *pagesetType, *repeatBenchmark, !*worker_common.Local)
				if noPatchErr != nil {
					if exec.IsTimeout(noPatchErr) {
						timeoutTracker.Increment()
					}
					// For Android runs make sure that the device is online. If not then stop early.
					if *targetPlatform == util.PLATFORM_ANDROID {
						if err := adb.VerifyLocalDevice(ctx); err != nil {
							sklog.Errorf("Could not find Android device: %s", err)
							return
						}
					}
				} else {
					timeoutTracker.Reset()
				}
				_, withPatchErr := util.RunBenchmark(ctx, pagesetName, pathToPagesets, pathToPyFiles, localOutputDirWithPatch, chromiumBinaryWithPatch, runIDWithPatch, *browserExtraArgsWithPatch, *benchmarkName, *targetPlatform, *benchmarkExtraArgs, *pagesetType, *repeatBenchmark, !*worker_common.Local)
				if withPatchErr != nil {
					if exec.IsTimeout(withPatchErr) {
						timeoutTracker.Increment()
					}
					// For Android runs make sure that the device is online. If not then stop early.
					if *targetPlatform == util.PLATFORM_ANDROID {
						if err := adb.VerifyLocalDevice(ctx); err != nil {
							sklog.Errorf("Could not find Android device: %s", err)
							return
						}
					}
				} else {
					timeoutTracker.Reset()
				}
				mutex.RUnlock()

				if timeoutTracker.Read() > MAX_ALLOWED_SEQUENTIAL_TIMEOUTS {
					sklog.Errorf("Ran into %d sequential timeouts. Something is wrong. Killing the goroutine.", MAX_ALLOWED_SEQUENTIAL_TIMEOUTS)
					return
				}
			}
		}()
	}

	if !*worker_common.Local {
		// Start the cleaner.
		go util.ChromeProcessesCleaner(ctx, &mutex, *chromeCleanerTimer)
	}

	// Wait for all spawned goroutines to complete.
	wg.Wait()

	if timeoutTracker.Read() > MAX_ALLOWED_SEQUENTIAL_TIMEOUTS {
		return fmt.Errorf("There were %d sequential timeouts.", MAX_ALLOWED_SEQUENTIAL_TIMEOUTS)
	}

	// If "--output-format=csv" is specified then merge all CSV files and upload.
	if strings.Contains(*benchmarkExtraArgs, "--output-format=csv") {
		if err := util.MergeUploadCSVFilesOnWorkers(ctx, localOutputDirNoPatch, pathToPyFiles, runIDNoPatch, remoteDirNoPatch, *valueColumnName, gs, *startRange, true /* handleStrings */, true /* addRanks */, map[string]map[string]string{} /* pageRankToAdditionalFields */); err != nil {
			return fmt.Errorf("Error while processing withpatch CSV files: %s", err)
		}
		if err := util.MergeUploadCSVFilesOnWorkers(ctx, localOutputDirWithPatch, pathToPyFiles, runIDWithPatch, remoteDirWithPatch, *valueColumnName, gs, *startRange, true /* handleStrings */, true /* addRanks */, map[string]map[string]string{} /* pageRankToAdditionalFields */); err != nil {
			return fmt.Errorf("Error while processing withpatch CSV files: %s", err)
		}
	}

	return nil
}

func main() {
	retCode := 0
	if err := runChromiumPerf(); err != nil {
		sklog.Errorf("Error while running chromium perf: %s", err)
		retCode = 255
	}
	os.Exit(retCode)
}