package main

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

	"github.com/google/uuid"
	swarming_api "go.chromium.org/luci/common/api/swarming/swarming/v1"
	"go.skia.org/infra/go/auth"
	"go.skia.org/infra/go/cipd"
	"go.skia.org/infra/go/common"
	"go.skia.org/infra/go/httputils"
	"go.skia.org/infra/go/isolate"
	"go.skia.org/infra/go/sklog"
	"go.skia.org/infra/go/swarming"
	"go.skia.org/infra/go/util"
)

/*
	Run a specified command on all specified GCE instances.
*/

const (
	ISOLATE_DEFAULT_NAMESPACE = "default-gzip"
	TMP_ISOLATE_FILE_NAME     = "script.isolate"
	TMP_ISOLATE_FILE_CONTENTS = `{
  'variables': {
    'files': [
      '%s',
    ],
  },
}`
)

var (
	dimensions  = common.NewMultiStringFlag("dimension", nil, "Colon-separated key/value pair, eg: \"os:Linux\" Dimensions of the bots on which to run. Can specify multiple times.")
	pool        = flag.String("pool", swarming.DIMENSION_POOL_VALUE_SKIA, "Which Swarming pool to use.")
	script      = flag.String("script", "", "Path to a Python script to run.")
	taskName    = flag.String("task_name", "", "Name of the task to run.")
	workdir     = flag.String("workdir", os.TempDir(), "Working directory. Optional, but recommended not to use CWD.")
	includeBots = common.NewMultiStringFlag("include_bot", nil, "If specified, treated as a white list of bots which will be affected, calculated AFTER the dimensions is computed. Can be simple strings or regexes")
	internal    = flag.Bool("internal", false, "Run against internal swarming and isolate instances.")
	dev         = flag.Bool("dev", false, "Run against dev swarming and isolate instances.")
	dryRun      = flag.Bool("dry_run", false, "List the bots, don't actually run any tasks")
)

func main() {
	// Setup, parse args.
	common.Init()

	ctx := context.Background()
	if *script == "" {
		sklog.Fatal("--script is required.")
	}
	if *internal && *dev {
		sklog.Fatal("Both --internal and --dev cannot be specified.")
	}
	scriptName := path.Base(*script)
	if *taskName == "" {
		*taskName = fmt.Sprintf("run_%s", scriptName)
	}

	dims, err := swarming.ParseDimensionsSingleValue(*dimensions)
	if err != nil {
		sklog.Fatalf("Problem parsing dimensions: %s", err)
	}
	dims["pool"] = *pool

	*workdir, err = filepath.Abs(*workdir)
	if err != nil {
		sklog.Fatal(err)
	}

	includeRegs, err := parseRegex(*includeBots)
	if err != nil {
		sklog.Fatal(err)
	}

	isolateServer := isolate.ISOLATE_SERVER_URL
	swarmingServer := swarming.SWARMING_SERVER
	if *internal {
		isolateServer = isolate.ISOLATE_SERVER_URL_PRIVATE
		swarmingServer = swarming.SWARMING_SERVER_PRIVATE
	} else if *dev {
		isolateServer = isolate.ISOLATE_SERVER_URL_DEV
		swarmingServer = swarming.SWARMING_SERVER_DEV
	}

	// Authenticated HTTP client.
	ts, err := auth.NewDefaultTokenSource(true, swarming.AUTH_SCOPE)
	if err != nil {
		sklog.Fatal(err)
	}
	httpClient := httputils.DefaultClientConfig().WithTokenSource(ts).With2xxOnly().Client()

	// Swarming API client.
	swarmApi, err := swarming.NewApiClient(httpClient, swarmingServer)
	if err != nil {
		sklog.Fatal(err)
	}

	// Obtain the list of bots.
	bots, err := swarmApi.ListBots(dims)
	if err != nil {
		sklog.Fatal(err)
	}

	if *dryRun {
		sklog.Info("Dry run mode.  Would run on following bots:")
		for _, b := range bots {
			sklog.Info(b.BotId)
		}
		return
	}

	// Copy the script to the workdir.
	isolateDir, err := ioutil.TempDir(*workdir, "run_on_swarming_bots")
	if err != nil {
		sklog.Fatal(err)
	}
	defer util.RemoveAll(isolateDir)
	dstScript := path.Join(isolateDir, scriptName)
	if err := util.CopyFile(*script, dstScript); err != nil {
		sklog.Fatal(err)
	}

	// Create an isolate file.
	isolateFile := path.Join(isolateDir, TMP_ISOLATE_FILE_NAME)
	if err := util.WithWriteFile(isolateFile, func(w io.Writer) error {
		_, err := w.Write([]byte(fmt.Sprintf(TMP_ISOLATE_FILE_CONTENTS, scriptName)))
		return err
	}); err != nil {
		sklog.Fatal(err)
	}

	// Upload to isolate server.
	isolateClient, err := isolate.NewClient(*workdir, isolateServer)
	if err != nil {
		sklog.Fatal(err)
	}
	isolateTask := &isolate.Task{
		BaseDir:     isolateDir,
		Blacklist:   isolate.DEFAULT_BLACKLIST,
		IsolateFile: isolateFile,
	}
	hashes, _, err := isolateClient.IsolateTasks(ctx, []*isolate.Task{isolateTask})
	if err != nil {
		sklog.Fatal(err)
	}

	// Trigger the task on each bot.
	cmd := []string{"python", "-u", scriptName}
	group := fmt.Sprintf("%s_%s", *taskName, uuid.New())
	tags := []string{
		fmt.Sprintf("group:%s", group),
	}
	var wg sync.WaitGroup
	for _, bot := range bots {
		if !matchesAny(bot.BotId, includeRegs) {
			sklog.Debugf("Skipping %s because it isn't in the whitelist", bot.BotId)
			continue
		}
		wg.Add(1)
		go func(id string) {
			defer wg.Done()
			dims := []*swarming_api.SwarmingRpcsStringPair{
				{
					Key:   "pool",
					Value: *pool,
				},
				{
					Key:   "id",
					Value: id,
				},
			}
			sklog.Infof("Triggering on %s", id)
			req := &swarming_api.SwarmingRpcsNewTaskRequest{
				ExpirationSecs: int64((120 * time.Minute).Seconds()),
				Name:           *taskName,
				Priority:       swarming.HIGHEST_PRIORITY,
				Properties: &swarming_api.SwarmingRpcsTaskProperties{
					Caches: []*swarming_api.SwarmingRpcsCacheEntry{
						{
							Name: "vpython",
							Path: "cache/vpython",
						},
					},
					CipdInput:  swarming.ConvertCIPDInput(cipd.PkgsPython),
					Command:    cmd,
					Dimensions: dims,
					EnvPrefixes: []*swarming_api.SwarmingRpcsStringListPair{
						{
							Key:   "PATH",
							Value: []string{"cipd_bin_packages", "cipd_bin_packages/bin"},
						},
						{
							Key:   "VPYTHON_VIRTUALENV_ROOT",
							Value: []string{"cache/vpython"},
						},
					},
					ExecutionTimeoutSecs: int64((120 * time.Minute).Seconds()),
					Idempotent:           false,
					InputsRef: &swarming_api.SwarmingRpcsFilesRef{
						Isolated:       hashes[0],
						Isolatedserver: isolateServer,
						Namespace:      isolate.DEFAULT_NAMESPACE,
					},
					IoTimeoutSecs: int64((120 * time.Minute).Seconds()),
				},
				Tags: tags,
			}
			if _, err := swarmApi.TriggerTask(req); err != nil {
				sklog.Fatal(err)
			}
		}(bot.BotId)
	}

	wg.Wait()
	tasksLink := fmt.Sprintf("https://%s/tasklist?f=group:%s", swarmingServer, group)
	sklog.Infof("Triggered Swarming tasks. Visit this link to track progress:\n%s", tasksLink)
}

func parseRegex(flags []string) (retval []*regexp.Regexp, e error) {
	for _, s := range flags {
		r, err := regexp.Compile(s)
		if err != nil {
			return nil, err
		}
		retval = append(retval, r)
	}
	return retval, nil
}

func matchesAny(s string, xr []*regexp.Regexp) bool {
	if len(xr) == 0 {
		return true
	}
	for _, r := range xr {
		if r.MatchString(s) {
			return true
		}
	}
	return false
}