refactor: simplify summary generation (resolve #68)

services/summary.go

@@ -4,14 +4,12 @@ import (
 	"crypto/md5"
 	"errors"
 	"github.com/muety/wakapi/config"
+	"github.com/muety/wakapi/models"
 	"github.com/muety/wakapi/repositories"
 	"github.com/patrickmn/go-cache"
 	"math"
 	"sort"
-	"strconv"
 	"time"
-
-	"github.com/muety/wakapi/models"
 )
 
 const HeartbeatDiffThreshold = 2 * time.Minute
@@ -24,6 +22,8 @@ type SummaryService struct {
 	aliasService     *AliasService
 }
 
+type SummaryRetriever func(f, t time.Time, u *models.User) (*models.Summary, error)
+
 func NewSummaryService(summaryRepo *repositories.SummaryRepository, heartbeatService *HeartbeatService, aliasService *AliasService) *SummaryService {
 	return &SummaryService{
 		config:           config.Get(),
@@ -34,60 +34,98 @@ func NewSummaryService(summaryRepo *repositories.SummaryRepository, heartbeatSer
 	}
 }
 
-type Interval struct {
-	Start time.Time
-	End   time.Time
-}
+// Public summary generation methods
 
-// TODO: simplify!
-func (srv *SummaryService) Construct(from, to time.Time, user *models.User, recompute bool) (*models.Summary, error) {
-	var existingSummaries []*models.Summary
-	var cacheKey string
-
-	if recompute {
-		existingSummaries = make([]*models.Summary, 0)
-	} else {
-		cacheKey = getHash([]time.Time{from, to}, user)
-		if result, ok := srv.cache.Get(cacheKey); ok {
-			return result.(*models.Summary), nil
-		}
-		summaries, err := srv.GetByUserWithin(user, from, to)
-		if err != nil {
-			return nil, err
-		}
-		existingSummaries = summaries
+func (srv *SummaryService) Aliased(from, to time.Time, user *models.User, f SummaryRetriever) (*models.Summary, error) {
+	// Check cache
+	cacheKey := srv.getHash(from.String(), to.String(), user.ID, "--aliased")
+	if cacheResult, ok := srv.cache.Get(cacheKey); ok {
+		return cacheResult.(*models.Summary), nil
 	}
 
-	missingIntervals := getMissingIntervals(from, to, existingSummaries)
+	// Wrap alias resolution
+	resolve := func(t uint8, k string) string {
+		s, _ := srv.aliasService.GetAliasOrDefault(user.ID, t, k)
+		return s
+	}
 
-	heartbeats := make([]*models.Heartbeat, 0)
+	// Initialize alias resolver service
+	if err := srv.aliasService.LoadUserAliases(user.ID); err != nil {
+		return nil, err
+	}
+
+	// Get actual summary
+	s, err := f(from, to, user)
+	if err != nil {
+		return nil, err
+	}
+
+	// Post-process summary and cache it
+	summary := s.WithResolvedAliases(resolve)
+	srv.cache.SetDefault(cacheKey, summary)
+	return summary, nil
+}
+
+func (srv *SummaryService) Retrieve(from, to time.Time, user *models.User) (*models.Summary, error) {
+	// Check cache
+	cacheKey := srv.getHash(from.String(), to.String(), user.ID, "--aliased")
+	if cacheResult, ok := srv.cache.Get(cacheKey); ok {
+		return cacheResult.(*models.Summary), nil
+	}
+
+	// Get all already existing, pre-generated summaries that fall into the requested interval
+	summaries, err := srv.repository.GetByUserWithin(user, from, to)
+	if err != nil {
+		return nil, err
+	}
+
+	// Generate missing slots (especially before and after existing summaries) from raw heartbeats
+	missingIntervals := srv.getMissingIntervals(from, to, summaries)
 	for _, interval := range missingIntervals {
-		hb, err := srv.heartbeatService.GetAllWithin(interval.Start, interval.End, user)
-		if err != nil {
+		if s, err := srv.Summarize(interval.Start, interval.End, user); err == nil {
+			summaries = append(summaries, s)
+		} else {
 			return nil, err
 		}
-		heartbeats = append(heartbeats, hb...)
+	}
+
+	// Merge existing and newly generated summary snippets
+	summary, err := srv.mergeSummaries(summaries)
+	if err != nil {
+		return nil, err
+	}
+
+	// Cache 'em
+	srv.cache.SetDefault(cacheKey, summary)
+	return summary, nil
+}
+
+func (srv *SummaryService) Summarize(from, to time.Time, user *models.User) (*models.Summary, error) {
+	// Initialize and fetch data
+	var heartbeats models.Heartbeats
+	if rawHeartbeats, err := srv.heartbeatService.GetAllWithin(from, to, user); err == nil {
+		heartbeats = rawHeartbeats
+	} else {
+		return nil, err
 	}
 
 	types := models.SummaryTypes()
 
+	typedAggregations := make(chan models.SummaryItemContainer)
+	defer close(typedAggregations)
+	for _, t := range types {
+		go srv.aggregateBy(heartbeats, t, typedAggregations)
+	}
+
+	// Aggregate raw heartbeats by types in parallel and collect them
 	var projectItems []*models.SummaryItem
 	var languageItems []*models.SummaryItem
 	var editorItems []*models.SummaryItem
 	var osItems []*models.SummaryItem
 	var machineItems []*models.SummaryItem
 
-	if err := srv.aliasService.LoadUserAliases(user.ID); err != nil {
-		return nil, err
-	}
-
-	c := make(chan models.SummaryItemContainer)
-	for _, t := range types {
-		go srv.aggregateBy(heartbeats, t, user, c)
-	}
-
 	for i := 0; i < len(types); i++ {
-		item := <-c
+		item := <-typedAggregations
 		switch item.Type {
 		case models.SummaryProject:
 			projectItems = item.Items
@@ -101,31 +139,16 @@ func (srv *SummaryService) Construct(from, to time.Time, user *models.User, reco
 			machineItems = item.Items
 		}
 	}
-	close(c)
 
-	realFrom, realTo := from, to
-	if len(existingSummaries) > 0 {
-		realFrom = existingSummaries[0].FromTime.T()
-		realTo = existingSummaries[len(existingSummaries)-1].ToTime.T()
-
-		for _, summary := range existingSummaries {
-			summary.FillUnknown()
-		}
-	}
-	if len(heartbeats) > 0 {
-		t1, t2 := time.Time(heartbeats[0].Time), time.Time(heartbeats[len(heartbeats)-1].Time)
-		if t1.After(realFrom) && t1.Before(time.Date(realFrom.Year(), realFrom.Month(), realFrom.Day()+1, 0, 0, 0, 0, realFrom.Location())) {
-			realFrom = t1
-		}
-		if t2.Before(realTo) && t2.After(time.Date(realTo.Year(), realTo.Month(), realTo.Day()-1, 0, 0, 0, 0, realTo.Location())) {
-			realTo = t2
-		}
+	if heartbeats.Len() > 0 {
+		from = time.Time(heartbeats.First().Time)
+		to = time.Time(heartbeats.Last().Time)
 	}
 
-	aggregatedSummary := &models.Summary{
+	summary := &models.Summary{
 		UserID:           user.ID,
-		FromTime:         models.CustomTime(realFrom),
-		ToTime:           models.CustomTime(realTo),
+		FromTime:         models.CustomTime(from),
+		ToTime:           models.CustomTime(to),
 		Projects:         projectItems,
 		Languages:        languageItems,
 		Editors:          editorItems,
@@ -133,123 +156,32 @@ func (srv *SummaryService) Construct(from, to time.Time, user *models.User, reco
 		Machines:         machineItems,
 	}
 
-	allSummaries := []*models.Summary{aggregatedSummary}
-	allSummaries = append(allSummaries, existingSummaries...)
-
-	summary, err := mergeSummaries(allSummaries)
-	if err != nil {
-		return nil, err
-	}
-
-	if cacheKey != "" {
-		srv.cache.SetDefault(cacheKey, summary)
-	}
+	summary.FillUnknown()
 
 	return summary, nil
 }
 
-func (srv *SummaryService) PostProcessWrapped(summary *models.Summary, err error) (*models.Summary, error) {
-	if err != nil {
-		return nil, err
-	}
-	return srv.PostProcess(summary), nil
-}
+// CRUD methods
 
-func (srv *SummaryService) PostProcess(summary *models.Summary) *models.Summary {
-	updatedSummary := &models.Summary{
-		ID:       summary.ID,
-		UserID:   summary.UserID,
-		FromTime: summary.FromTime,
-		ToTime:   summary.ToTime,
-	}
-
-	processAliases := func(origin []*models.SummaryItem) []*models.SummaryItem {
-		target := make([]*models.SummaryItem, 0)
-
-		findItem := func(key string) *models.SummaryItem {
-			for _, item := range target {
-				if item.Key == key {
-					return item
-				}
-			}
-			return nil
-		}
-
-		for _, item := range origin {
-			// Add all "top-level" items, i.e. such without aliases
-			if key, _ := srv.aliasService.GetAliasOrDefault(summary.UserID, item.Type, item.Key); key == item.Key {
-				target = append(target, item)
-			}
-		}
-
-		for _, item := range origin {
-			// Add all remaining projects and merge with their alias
-			if key, _ := srv.aliasService.GetAliasOrDefault(summary.UserID, item.Type, item.Key); key != item.Key {
-				if targetItem := findItem(key); targetItem != nil {
-					targetItem.Total += item.Total
-				} else {
-					target = append(target, &models.SummaryItem{
-						ID:        item.ID,
-						SummaryID: item.SummaryID,
-						Type:      item.Type,
-						Key:       key,
-						Total:     item.Total,
-					})
-				}
-			}
-		}
-
-		return target
-	}
-
-	// Resolve aliases
-	updatedSummary.Projects = processAliases(summary.Projects)
-	updatedSummary.Editors = processAliases(summary.Editors)
-	updatedSummary.Languages = processAliases(summary.Languages)
-	updatedSummary.OperatingSystems = processAliases(summary.OperatingSystems)
-	updatedSummary.Machines = processAliases(summary.Machines)
-
-	return updatedSummary
-}
-
-func (srv *SummaryService) Insert(summary *models.Summary) error {
-	return srv.repository.Insert(summary)
-}
-
-func (srv *SummaryService) GetByUserWithin(user *models.User, from, to time.Time) ([]*models.Summary, error) {
-	return srv.repository.GetByUserWithin(user, from, to)
-}
-
-// Will return *models.Index objects with only user_id and to_time filled
-func (srv *SummaryService) GetLatestByUser() ([]*models.Summary, error) {
-	return srv.repository.GetLatestByUser()
+func (srv *SummaryService) GetLatestByUser() ([]*models.TimeByUser, error) {
+	return srv.repository.GetLastByUser()
 }
 
 func (srv *SummaryService) DeleteByUser(userId string) error {
 	return srv.repository.DeleteByUser(userId)
 }
 
-func (srv *SummaryService) aggregateBy(heartbeats []*models.Heartbeat, summaryType uint8, user *models.User, c chan models.SummaryItemContainer) {
+func (srv *SummaryService) Insert(summary *models.Summary) error {
+	return srv.repository.Insert(summary)
+}
+
+// Private summary generation and utility methods
+
+func (srv *SummaryService) aggregateBy(heartbeats []*models.Heartbeat, summaryType uint8, c chan models.SummaryItemContainer) {
 	durations := make(map[string]time.Duration)
 
 	for i, h := range heartbeats {
-		var key string
-		switch summaryType {
-		case models.SummaryProject:
-			key = h.Project
-		case models.SummaryEditor:
-			key = h.Editor
-		case models.SummaryLanguage:
-			key = h.Language
-		case models.SummaryOS:
-			key = h.OperatingSystem
-		case models.SummaryMachine:
-			key = h.Machine
-		}
-
-		if key == "" {
-			key = models.UnknownSummaryKey
-		}
+		key := h.GetKey(summaryType)
 
 		if _, ok := durations[key]; !ok {
 			durations[key] = time.Duration(0)
@@ -287,43 +219,7 @@ func (srv *SummaryService) aggregateBy(heartbeats []*models.Heartbeat, summaryTy
 	c <- models.SummaryItemContainer{Type: summaryType, Items: items}
 }
 
-func getMissingIntervals(from, to time.Time, existingSummaries []*models.Summary) []*Interval {
-	if len(existingSummaries) == 0 {
-		return []*Interval{{from, to}}
-	}
-
-	intervals := make([]*Interval, 0)
-
-	// Pre
-	if from.Before(existingSummaries[0].FromTime.T()) {
-		intervals = append(intervals, &Interval{from, existingSummaries[0].FromTime.T()})
-	}
-
-	// Between
-	for i := 0; i < len(existingSummaries)-1; i++ {
-		t1, t2 := existingSummaries[i].ToTime.T(), existingSummaries[i+1].FromTime.T()
-		if t1.Equal(t2) {
-			continue
-		}
-
-		// round to end of day / start of day, assuming that summaries are always generated on a per-day basis
-		td1 := time.Date(t1.Year(), t1.Month(), t1.Day()+1, 0, 0, 0, 0, t1.Location())
-		td2 := time.Date(t2.Year(), t2.Month(), t2.Day(), 0, 0, 0, 0, t2.Location())
-		// one or more day missing in between?
-		if td1.Before(td2) {
-			intervals = append(intervals, &Interval{existingSummaries[i].ToTime.T(), existingSummaries[i+1].FromTime.T()})
-		}
-	}
-
-	// Post
-	if to.After(existingSummaries[len(existingSummaries)-1].ToTime.T()) {
-		intervals = append(intervals, &Interval{existingSummaries[len(existingSummaries)-1].ToTime.T(), to})
-	}
-
-	return intervals
-}
-
-func mergeSummaries(summaries []*models.Summary) (*models.Summary, error) {
+func (srv *SummaryService) mergeSummaries(summaries []*models.Summary) (*models.Summary, error) {
 	if len(summaries) < 1 {
 		return nil, errors.New("no summaries given")
 	}
@@ -353,11 +249,11 @@ func mergeSummaries(summaries []*models.Summary) (*models.Summary, error) {
 			maxTime = s.ToTime.T()
 		}
 
-		finalSummary.Projects = mergeSummaryItems(finalSummary.Projects, s.Projects)
-		finalSummary.Languages = mergeSummaryItems(finalSummary.Languages, s.Languages)
-		finalSummary.Editors = mergeSummaryItems(finalSummary.Editors, s.Editors)
-		finalSummary.OperatingSystems = mergeSummaryItems(finalSummary.OperatingSystems, s.OperatingSystems)
-		finalSummary.Machines = mergeSummaryItems(finalSummary.Machines, s.Machines)
+		finalSummary.Projects = srv.mergeSummaryItems(finalSummary.Projects, s.Projects)
+		finalSummary.Languages = srv.mergeSummaryItems(finalSummary.Languages, s.Languages)
+		finalSummary.Editors = srv.mergeSummaryItems(finalSummary.Editors, s.Editors)
+		finalSummary.OperatingSystems = srv.mergeSummaryItems(finalSummary.OperatingSystems, s.OperatingSystems)
+		finalSummary.Machines = srv.mergeSummaryItems(finalSummary.Machines, s.Machines)
 	}
 
 	finalSummary.FromTime = models.CustomTime(minTime)
@@ -366,7 +262,7 @@ func mergeSummaries(summaries []*models.Summary) (*models.Summary, error) {
 	return finalSummary, nil
 }
 
-func mergeSummaryItems(existing []*models.SummaryItem, new []*models.SummaryItem) []*models.SummaryItem {
+func (srv *SummaryService) mergeSummaryItems(existing []*models.SummaryItem, new []*models.SummaryItem) []*models.SummaryItem {
 	items := make(map[string]*models.SummaryItem)
 
 	// Build map from existing
@@ -396,11 +292,46 @@ func mergeSummaryItems(existing []*models.SummaryItem, new []*models.SummaryItem
 	return itemList
 }
 
-func getHash(times []time.Time, user *models.User) string {
-	digest := md5.New()
-	for _, t := range times {
-		digest.Write([]byte(strconv.Itoa(int(t.Unix()))))
+func (srv *SummaryService) getMissingIntervals(from, to time.Time, summaries []*models.Summary) []*models.Interval {
+	if len(summaries) == 0 {
+		return []*models.Interval{{from, to}}
+	}
+
+	intervals := make([]*models.Interval, 0)
+
+	// Pre
+	if from.Before(summaries[0].FromTime.T()) {
+		intervals = append(intervals, &models.Interval{from, summaries[0].FromTime.T()})
+	}
+
+	// Between
+	for i := 0; i < len(summaries)-1; i++ {
+		t1, t2 := summaries[i].ToTime.T(), summaries[i+1].FromTime.T()
+		if t1.Equal(t2) {
+			continue
+		}
+
+		// round to end of day / start of day, assuming that summaries are always generated on a per-day basis
+		td1 := time.Date(t1.Year(), t1.Month(), t1.Day()+1, 0, 0, 0, 0, t1.Location())
+		td2 := time.Date(t2.Year(), t2.Month(), t2.Day(), 0, 0, 0, 0, t2.Location())
+		// one or more day missing in between?
+		if td1.Before(td2) {
+			intervals = append(intervals, &models.Interval{summaries[i].ToTime.T(), summaries[i+1].FromTime.T()})
+		}
+	}
+
+	// Post
+	if to.After(summaries[len(summaries)-1].ToTime.T()) {
+		intervals = append(intervals, &models.Interval{summaries[len(summaries)-1].ToTime.T(), to})
+	}
+
+	return intervals
+}
+
+func (srv *SummaryService) getHash(args ...string) string {
+	digest := md5.New()
+	for _, a := range args {
+		digest.Write([]byte(a))
 	}
-	digest.Write([]byte(user.ID))
 	return string(digest.Sum(nil))
 }