From 04c3effcea7bfdff54243068734c0296b58eb789 Mon Sep 17 00:00:00 2001
From: Chris Cummer <chriscummer@me.com>
Date: Wed, 11 Apr 2018 13:32:13 -0700
Subject: [PATCH] Mark calendar start time conflicts

---
 gcal/client.go | 10 +++++-----
 gcal/widget.go | 53 +++++++++++++++++++++++++++++++++++++++-----------
 2 files changed, 47 insertions(+), 16 deletions(-)

diff --git a/gcal/client.go b/gcal/client.go
index 7da0aa8e..19f97f4a 100644
--- a/gcal/client.go
+++ b/gcal/client.go
@@ -58,6 +58,11 @@ func Fetch() (*calendar.Events, error) {
 
 /* -------------------- Unexported Functions -------------------- */
 
+func fromMidnight() time.Time {
+	now := time.Now()
+	return time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
+}
+
 // getClient uses a Context and Config to retrieve a Token
 // then generate a Client. It returns the generated Client.
 func getClient(ctx context.Context, config *oauth2.Config) *http.Client {
@@ -92,11 +97,6 @@ func getTokenFromWeb(config *oauth2.Config) *oauth2.Token {
 	return tok
 }
 
-func fromMidnight() time.Time {
-	now := time.Now()
-	return time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
-}
-
 // tokenCacheFile generates credential file path/filename.
 // It returns the generated credential path/filename.
 func tokenCacheFile() (string, error) {
diff --git a/gcal/widget.go b/gcal/widget.go
index ed7ede62..457e944a 100644
--- a/gcal/widget.go
+++ b/gcal/widget.go
@@ -67,11 +67,13 @@ func (widget *Widget) contentFrom(events *calendar.Events) string {
 
 	str := ""
 	for _, event := range events.Items {
+		conflict := widget.hasConflict(event, events)
+
 		str = str + fmt.Sprintf(
 			"%s [%s]%s[white]\n [%s]%s %s[white]\n\n",
 			widget.dayDivider(event, prevEvent),
 			widget.titleColor(event),
-			widget.eventSummary(event),
+			widget.eventSummary(event, conflict),
 			widget.descriptionColor(event),
 			widget.eventTimestamp(event),
 			widget.until(event),
@@ -96,12 +98,33 @@ func (widget *Widget) dayDivider(event, prevEvent *calendar.Event) string {
 	return ""
 }
 
-func (widget *Widget) eventSummary(event *calendar.Event) string {
-	if widget.eventIsNow(event) {
-		return fmt.Sprintf("%s %s", Config.UString("wtf.mods.gcal.currentIcon", "🔸"), event.Summary)
+func (widget *Widget) descriptionColor(event *calendar.Event) string {
+	ts, _ := time.Parse(time.RFC3339, event.Start.DateTime)
+
+	color := "white"
+	if (widget.eventIsNow(event) == false) && ts.Before(time.Now()) {
+		color = "grey"
 	}
 
-	return event.Summary
+	return color
+}
+
+func (widget *Widget) eventSummary(event *calendar.Event, conflict bool) string {
+	summary := event.Summary
+
+	if widget.eventIsNow(event) {
+		summary = fmt.Sprintf(
+			"%s %s",
+			Config.UString("wtf.mods.gcal.currentIcon", "🔸"),
+			event.Summary,
+		)
+	}
+
+	if conflict {
+		return fmt.Sprintf("%s %s", Config.UString("wtf.mods.gcal.conflictIcon", "🚨"), summary)
+	} else {
+		return event.Summary
+	}
 }
 
 func (widget *Widget) eventTimestamp(event *calendar.Event) string {
@@ -117,15 +140,23 @@ func (widget *Widget) eventIsNow(event *calendar.Event) bool {
 	return time.Now().After(startTime) && time.Now().Before(endTime)
 }
 
-func (widget *Widget) descriptionColor(event *calendar.Event) string {
-	ts, _ := time.Parse(time.RFC3339, event.Start.DateTime)
+// hasConflict returns TRUE if this event conflicts with another, FALSE if it does not
+// Very basic implementation. Should really operate on ranges
+func (widget *Widget) hasConflict(event *calendar.Event, events *calendar.Events) bool {
+	conflict := false
 
-	color := "white"
-	if (widget.eventIsNow(event) == false) && ts.Before(time.Now()) {
-		color = "grey"
+	for _, otherEvent := range events.Items {
+		if event == otherEvent {
+			continue
+		}
+
+		if event.Start.DateTime == otherEvent.Start.DateTime {
+			conflict = true
+			break
+		}
 	}
 
-	return color
+	return conflict
 }
 
 func (widget *Widget) titleColor(event *calendar.Event) string {