/*
	The Cluster Telemetry Frontend.
*/

package main

import (
	"context"
	"flag"
	"fmt"
	"io"
	"net/http"
	"path/filepath"
	"runtime"
	"strconv"
	"strings"
	"time"

	"github.com/go-chi/chi/v5"
	apipb "go.chromium.org/luci/swarming/proto/api_v2"
	"go.skia.org/infra/ct/go/ctfe/admin_tasks"
	"go.skia.org/infra/ct/go/ctfe/chromium_analysis"
	"go.skia.org/infra/ct/go/ctfe/chromium_perf"
	"go.skia.org/infra/ct/go/ctfe/metrics_analysis"
	"go.skia.org/infra/ct/go/ctfe/pending_tasks"
	"go.skia.org/infra/ct/go/ctfe/task_common"
	"go.skia.org/infra/ct/go/ctfe/task_types"
	ctfeutil "go.skia.org/infra/ct/go/ctfe/util"
	ctutil "go.skia.org/infra/ct/go/util"
	"go.skia.org/infra/go/alogin"
	"go.skia.org/infra/go/alogin/proxylogin"
	"go.skia.org/infra/go/auth"
	"go.skia.org/infra/go/cas/rbe"
	"go.skia.org/infra/go/common"
	"go.skia.org/infra/go/ds"
	"go.skia.org/infra/go/httputils"
	"go.skia.org/infra/go/metrics2"
	"go.skia.org/infra/go/roles"
	"go.skia.org/infra/go/sklog"
	"go.skia.org/infra/go/swarming"
	swarmingv2 "go.skia.org/infra/go/swarming/v2"
	skutil "go.skia.org/infra/go/util"
	"golang.org/x/oauth2/google"
	"google.golang.org/api/compute/v1"
	"google.golang.org/api/option"
)

var (
	// flags
	host               = flag.String("host", "localhost", "HTTP service host")
	promPort           = flag.String("prom_port", ":20000", "Metrics service address (e.g., ':20000')")
	port               = flag.String("port", ":8000", "HTTP service port (e.g., ':8000')")
	internalPort       = flag.String("internal_port", ":9000", "HTTP service internal port (e.g., ':9000')")
	local              = flag.Bool("local", false, "Running locally if true. As opposed to in production.")
	serviceAccountFile = flag.String("service_account_file", "/var/secrets/google/key.json", "Service account JSON file.")
	enableAutoscaler   = flag.Bool("enable_autoscaler", false, "Enable the CT autoscaler if this is set. The autoscaler will automatically bring up/down CT GCE instances based on which tasks are running.")

	resourcesDir           = flag.String("resources_dir", "", "The directory to find templates, JS, and CSS files. If blank the current directory will be used.")
	tasksSchedulerWaitTime = flag.Duration("tasks_scheduler_wait_time", 5*time.Minute, "How often the repeated tasks scheduler should run.")

	// Datastore params
	namespace   = flag.String("namespace", "cluster-telemetry", "The Cloud Datastore namespace, such as 'cluster-telemetry'.")
	projectName = flag.String("project_name", "skia-public", "The Google Cloud project name.")

	// Authenticated http client
	client *http.Client
	// Swarming API client.
	swarm swarmingv2.SwarmingV2Client

	plogin alogin.Login
)

func reloadTemplates() {
	if *resourcesDir == "" {
		// If resourcesDir is not specified then consider the directory two directories up from this
		// source file as the resourcesDir.
		_, filename, _, _ := runtime.Caller(0)
		*resourcesDir = filepath.Join(filepath.Dir(filename), "../..")
	}
	admin_tasks.ReloadTemplates(*resourcesDir)
	chromium_analysis.ReloadTemplates(*resourcesDir)
	chromium_perf.ReloadTemplates(*resourcesDir)
	metrics_analysis.ReloadTemplates(*resourcesDir)
	pending_tasks.ReloadTemplates(*resourcesDir)
}

func Init() {
	reloadTemplates()
}

func getIntParam(name string, r *http.Request) (*int, error) {
	raw, ok := r.URL.Query()[name]
	if !ok {
		return nil, nil
	}
	v64, err := strconv.ParseInt(raw[0], 10, 32)
	if err != nil {
		return nil, fmt.Errorf("Invalid value for parameter %q: %s -- %v", name, raw, err)
	}
	v32 := int(v64)
	return &v32, nil
}

func runServer(serverURL string) {
	externalRouter := chi.NewRouter()
	externalRouter.Handle("/dist/*", http.StripPrefix("/dist/", http.HandlerFunc(httputils.MakeResourceHandler(*resourcesDir))))

	admin_tasks.AddHandlers(externalRouter)
	chromium_analysis.AddHandlers(externalRouter)
	chromium_perf.AddHandlers(externalRouter) // Note: chromium_perf adds a handler for "/".
	metrics_analysis.AddHandlers(externalRouter)
	pending_tasks.AddHandlers(externalRouter)

	task_common.AddHandlers(externalRouter)

	// Handler for displaying results stored in Google Storage.
	externalRouter.HandleFunc(ctfeutil.RESULTS_URI+"*", resultsHandler)

	externalRouter.HandleFunc("/_/login/status", alogin.LoginStatusHandler(plogin))

	h := httputils.LoggingGzipRequestResponse(externalRouter)
	if !*local {
		h = alogin.ForceRole(h, plogin, roles.Viewer)
	}
	h = httputils.HealthzAndHTTPS(h)
	http.Handle("/", h)

	sklog.Infof("Ready to serve on %s", serverURL)
	sklog.Fatal(http.ListenAndServe(*port, nil))
}

// startCtfeMetrics registers metrics which indicate CT is running healthily
// and starts a goroutine to update them periodically.
func startCtfeMetrics(ctx context.Context) {
	pendingTasksGauge := metrics2.GetInt64Metric("num_pending_tasks")
	oldestPendingTaskAgeGauge := metrics2.GetFloat64Metric("oldest_pending_task_age")
	// 0=no tasks pending; 1=started; 2=not started
	oldestPendingTaskStatusGauge := metrics2.GetInt64Metric("oldest_pending_task_status")
	go func() {
		for range time.Tick(common.SAMPLE_PERIOD) {
			pendingTaskCount, err := pending_tasks.GetPendingTaskCount(ctx)
			if err != nil {
				sklog.Error(err)
			} else {
				pendingTasksGauge.Update(pendingTaskCount)
			}

			oldestPendingTask, err := pending_tasks.GetOldestPendingTask(ctx)
			if err != nil {
				sklog.Error(err)
			} else if oldestPendingTask == nil {
				oldestPendingTaskAgeGauge.Update(0)
				oldestPendingTaskStatusGauge.Update(0)
			} else {
				addedTime := ctutil.GetTimeFromTs(strconv.FormatInt(oldestPendingTask.GetCommonCols().TsAdded, 10))
				oldestPendingTaskAgeGauge.Update(time.Since(addedTime).Seconds())
				if oldestPendingTask.GetCommonCols().TsStarted != 0 {
					oldestPendingTaskStatusGauge.Update(1)
				} else {
					oldestPendingTaskStatusGauge.Update(2)
				}
			}
		}
	}()
}

func pollMasterScriptSwarmingTasks(ctx context.Context) {

	for range time.Tick(2 * time.Minute) {
		params := task_common.QueryParams{
			PendingOnly: true,
			Offset:      0,
			Size:        task_common.MAX_PAGE_SIZE,
		}
		for _, prototype := range task_types.Prototypes() {
			it := task_common.DatastoreTaskQuery(ctx, prototype, params)
			data, err := prototype.Query(it)
			if err != nil {
				sklog.Errorf("Failed to query %s tasks: %v", prototype.GetTaskName(), err)
				continue
			}

			tasks := task_common.AsTaskSlice(data)
			for _, task := range tasks {
				swarmingTaskID := task.GetCommonCols().SwarmingTaskID
				if swarmingTaskID == "" {
					sklog.Infof("The task %v has not been triggered yet", task)
					continue
				}
				swarmingTask, err := swarm.GetResult(ctx, &apipb.TaskIdWithPerfRequest{
					TaskId:                  swarmingTaskID,
					IncludePerformanceStats: false,
				})
				if err != nil {
					sklog.Errorf("Failed to get task %s for %s: %s", swarmingTaskID, prototype.GetTaskName(), err)
					continue
				}
				failure := false
				taskCompleted := false
				switch swarmingTask.State {
				case apipb.TaskState_BOT_DIED, apipb.TaskState_CANCELED, apipb.TaskState_CLIENT_ERROR, apipb.TaskState_EXPIRED, apipb.TaskState_NO_RESOURCE, apipb.TaskState_TIMED_OUT, apipb.TaskState_KILLED:
					sklog.Errorf("The task %s exited early with state %v", swarmingTaskID, swarmingTask.State)
					taskCompleted = true
					failure = true
				case apipb.TaskState_PENDING:
					sklog.Infof("The task %s is in pending state", swarmingTaskID)
				case apipb.TaskState_RUNNING:
					sklog.Infof("The task %s is in running state", swarmingTaskID)
				case apipb.TaskState_COMPLETED:
					taskCompleted = true
					if swarmingTask.Failure {
						sklog.Infof("The task %s failed", swarmingTaskID)
						failure = true
					} else {
						sklog.Infof("The task %s successfully completed", swarmingTaskID)
					}
				default:
					sklog.Errorf("Unknown Swarming State %v in %v", swarmingTask.State.String(), swarmingTask)
				}

				if taskCompleted {
					// Update the task in datastore.
					if err := task_common.UpdateTaskSetCompleted(ctx, task, !failure); err != nil {
						sklog.Errorf("Failed to update task %d in the datastore: %s", task.GetCommonCols().DatastoreKey.ID, err)
					} else {
						// Send completion email.
						skutil.LogErr(task.SendCompletionEmail(ctx, !failure))
					}
				}
			}
		}
	}
}

// repeatedTasksScheduler looks for all tasks that contain repeat_after_days
// set to > 0 and schedules them when the specified time comes.
// The function does the following:
//  1. Look for tasks that need to be scheduled in the next 5 minutes.
//  2. Loop over these tasks.
//     2.1 Schedule the task again and set repeat_after_days to what it
//     originally was.
//     2.2 Update the original task and set repeat_after_days to 0 since the
//     newly created task will now replace it.
func repeatedTasksScheduler(ctx context.Context) {

	for range time.Tick(*tasksSchedulerWaitTime) {
		// Loop over all tasks to find tasks which need to be scheduled.
		for _, prototype := range task_types.Prototypes() {

			it := task_common.DatastoreTaskQuery(ctx, prototype,
				task_common.QueryParams{
					FutureRunsOnly: true,
					Offset:         0,
					Size:           task_common.MAX_PAGE_SIZE,
				})
			data, err := prototype.Query(it)
			if err != nil {
				sklog.Errorf("Failed to query %s tasks: %v", prototype.GetTaskName(), err)
				continue
			}

			tasks := task_common.AsTaskSlice(data)
			for _, task := range tasks {
				addedTime := ctutil.GetTimeFromTs(strconv.FormatInt(task.GetCommonCols().TsAdded, 10))
				scheduledTime := addedTime.Add(time.Duration(task.GetCommonCols().RepeatAfterDays) * time.Hour * 24)

				cutOffTime := time.Now().UTC().Add(*tasksSchedulerWaitTime)
				if scheduledTime.Before(cutOffTime) {
					addTaskVars, err := task.GetPopulatedAddTaskVars()
					if err != nil {
						sklog.Errorf("Failed to get populated addTaskVars %v: %s", task, err)
						continue
					}
					if err := task_common.AddAndTriggerTask(ctx, addTaskVars); err != nil {
						sklog.Errorf("Failed to add or trigger task %v: %s", task, err)
						continue
					}

					// Clear the repeat after days field for the original task.
					task.GetCommonCols().RepeatAfterDays = 0
					if _, err := ds.DS.Put(ctx, task.GetCommonCols().DatastoreKey, task); err != nil {
						sklog.Errorf("Failed to update task %d in the datastore: %s", task.GetCommonCols().DatastoreKey.ID, err)
						continue
					}
				}
			}
		}
	}
}

func resultsHandler(w http.ResponseWriter, r *http.Request) {
	sklog.Infof("Requesting: %s", r.RequestURI)

	storageURL := fmt.Sprintf("https://storage.googleapis.com/%s", strings.TrimLeft(r.URL.Path, ctfeutil.RESULTS_URI))
	resp, err := client.Get(storageURL)
	if err != nil {
		sklog.Errorf("resultsHandler: Unable to get data from %s: %s", storageURL, err)
		httputils.ReportError(w, err, "Unable to get data from google storage", http.StatusInternalServerError)
		return
	}
	defer skutil.Close(resp.Body)
	if resp.StatusCode != 200 {
		sklog.Errorf("resultsHandler: %s returned %d", storageURL, resp.StatusCode)
		httputils.ReportError(w, nil, fmt.Sprintf("Google storage request returned %d", resp.StatusCode), http.StatusInternalServerError)
		return
	}
	w.Header().Set("Content-Type", resp.Header.Get("Content-Type"))
	if _, err := io.Copy(w, resp.Body); err != nil {
		sklog.Errorf("Error when copying response from %s: %s", storageURL, err)
		httputils.ReportError(w, err, "Error when copying response from google storage", http.StatusInternalServerError)
		return
	}
}

func main() {

	ctfeutil.PreExecuteTemplateHook = func() {
		// Don't use cached templates in local mode.
		if *local {
			reloadTemplates()
		}
	}

	common.InitWithMust(
		"ctfe",
		common.PrometheusOpt(promPort),
	)
	ctx := context.Background()

	Init()
	serverURL := "https://" + *host
	if *local {
		serverURL = "http://" + *host + *port
	}

	plogin = proxylogin.NewWithDefaults()
	task_common.SetLogin(plogin)

	// Initialize the datastore.
	dsTokenSource, err := google.DefaultTokenSource(ctx, "https://www.googleapis.com/auth/datastore")
	if err != nil {
		sklog.Fatalf("Problem setting up default token source: %s", err)
	}
	if err := ds.InitWithOpt(*projectName, *namespace, option.WithTokenSource(dsTokenSource)); err != nil {
		sklog.Fatalf("Could not init datastore: %s", err)
	}

	// Create authenticated HTTP client.
	httpClientTokenSource, err := google.DefaultTokenSource(ctx, auth.ScopeReadOnly, swarming.AUTH_SCOPE)
	if err != nil {
		sklog.Fatalf("Problem setting up default token source: %s", err)
	}
	client = httputils.DefaultClientConfig().WithTokenSource(httpClientTokenSource).With2xxOnly().Client()
	swarm = swarmingv2.NewDefaultClient(client, swarming.SWARMING_SERVER_PRIVATE)
	casTokenSource, err := google.DefaultTokenSource(ctx, compute.CloudPlatformScope)
	if err != nil {
		sklog.Fatalf("Failed to set up CAS token source: %s", err)
	}
	casClient, err := rbe.NewClient(ctx, rbe.InstanceChromeSwarming, casTokenSource)
	if err != nil {
		sklog.Fatalf("Failed to create CAS client: %s", err)
	}

	// Initialize the autoscaler and globals in task_common.
	if err := task_common.Init(ctx, *local, *enableAutoscaler, *host, *serviceAccountFile, swarm, casClient, pending_tasks.GetGCEPendingTaskCount); err != nil {
		sklog.Fatalf("Could not init task_common: %s", err)
	}

	startCtfeMetrics(ctx)

	// Start the repeated tasks scheduler.
	go repeatedTasksScheduler(ctx)

	// Start a poller that watches for completed master script swarming tasks.
	go pollMasterScriptSwarmingTasks(ctx)

	runServer(serverURL)
}