Add field to Ranking model to track previous rank.

tournament/qualification_rankings.go

@@ -13,10 +13,10 @@ import (
 )
 
 // Determines the rankings from the stored match results, and saves them to the database.
-func CalculateRankings(database *model.Database) error {
+func CalculateRankings(database *model.Database, preservePreviousRank bool) (game.Rankings, error) {
 	matches, err := database.GetMatchesByType("qualification")
 	if err != nil {
-		return err
+		return nil, err
 	}
 	rankings := make(map[int]*game.Ranking)
 	for _, match := range matches {
@@ -25,7 +25,7 @@ func CalculateRankings(database *model.Database) error {
 		}
 		matchResult, err := database.GetMatchResultForMatch(match.Id)
 		if err != nil {
-			return err
+			return nil, err
 		}
 		if !match.Red1IsSurrogate {
 			addMatchResultToRankings(rankings, match.Red1, matchResult, true)
@@ -47,16 +47,33 @@ func CalculateRankings(database *model.Database) error {
 		}
 	}
 
+	// Retrieve old rankings so that we can display changes in rank as a result of this calculation.
+	oldRankings, err := database.GetAllRankings()
+	if err != nil {
+		return nil, err
+	}
+	oldRankingsMap := make(map[int]game.Ranking, len(oldRankings))
+	for _, ranking := range oldRankings {
+		oldRankingsMap[ranking.TeamId] = ranking
+	}
+
 	sortedRankings := sortRankings(rankings)
 	for rank, ranking := range sortedRankings {
-		ranking.Rank = rank + 1
+		sortedRankings[rank].Rank = rank + 1
+		if oldRank, ok := oldRankingsMap[ranking.TeamId]; ok {
+			if preservePreviousRank {
+				sortedRankings[rank].PreviousRank = oldRank.PreviousRank
+			} else {
+				sortedRankings[rank].PreviousRank = oldRank.Rank
+			}
+		}
 	}
 	err = database.ReplaceAllRankings(sortedRankings)
 	if err != nil {
-		return nil
+		return nil, err
 	}
 
-	return nil
+	return sortedRankings, nil
 }
 
 // Checks all the match results for yellow and red cards, and updates the team model accordingly.
@@ -140,7 +157,7 @@ func addMatchResultToRankings(rankings map[int]*game.Ranking, teamId int, matchR
 func sortRankings(rankings map[int]*game.Ranking) game.Rankings {
 	var sortedRankings game.Rankings
 	for _, ranking := range rankings {
-		sortedRankings = append(sortedRankings, ranking)
+		sortedRankings = append(sortedRankings, *ranking)
 	}
 	sort.Sort(sortedRankings)
 	return sortedRankings

tournament/qualification_rankings_test.go

@@ -13,17 +13,24 @@ func TestCalculateRankings(t *testing.T) {
 	database := setupTestDb(t)
 
 	setupMatchResultsForRankings(database)
-	err := CalculateRankings(database)
+	updatedRankings, err := CalculateRankings(database, false)
 	assert.Nil(t, err)
 	rankings, err := database.GetAllRankings()
 	assert.Nil(t, err)
+	assert.Equal(t, updatedRankings, rankings)
 	if assert.Equal(t, 6, len(rankings)) {
 		assert.Equal(t, 4, rankings[0].TeamId)
+		assert.Equal(t, 0, rankings[0].PreviousRank)
 		assert.Equal(t, 5, rankings[1].TeamId)
+		assert.Equal(t, 0, rankings[1].PreviousRank)
 		assert.Equal(t, 6, rankings[2].TeamId)
+		assert.Equal(t, 0, rankings[2].PreviousRank)
 		assert.Equal(t, 1, rankings[3].TeamId)
+		assert.Equal(t, 0, rankings[3].PreviousRank)
 		assert.Equal(t, 3, rankings[4].TeamId)
+		assert.Equal(t, 0, rankings[4].PreviousRank)
 		assert.Equal(t, 2, rankings[5].TeamId)
+		assert.Equal(t, 0, rankings[5].PreviousRank)
 	}
 
 	// Test after changing a match result.
@@ -31,17 +38,47 @@ func TestCalculateRankings(t *testing.T) {
 	matchResult3.RedScore, matchResult3.BlueScore = matchResult3.BlueScore, matchResult3.RedScore
 	err = database.CreateMatchResult(matchResult3)
 	assert.Nil(t, err)
-	err = CalculateRankings(database)
+	updatedRankings, err = CalculateRankings(database, false)
 	assert.Nil(t, err)
 	rankings, err = database.GetAllRankings()
 	assert.Nil(t, err)
+	assert.Equal(t, updatedRankings, rankings)
 	if assert.Equal(t, 6, len(rankings)) {
 		assert.Equal(t, 6, rankings[0].TeamId)
+		assert.Equal(t, 3, rankings[0].PreviousRank)
 		assert.Equal(t, 5, rankings[1].TeamId)
+		assert.Equal(t, 2, rankings[1].PreviousRank)
 		assert.Equal(t, 4, rankings[2].TeamId)
+		assert.Equal(t, 1, rankings[2].PreviousRank)
 		assert.Equal(t, 1, rankings[3].TeamId)
+		assert.Equal(t, 4, rankings[3].PreviousRank)
 		assert.Equal(t, 3, rankings[4].TeamId)
+		assert.Equal(t, 5, rankings[4].PreviousRank)
 		assert.Equal(t, 2, rankings[5].TeamId)
+		assert.Equal(t, 6, rankings[5].PreviousRank)
+	}
+
+	matchResult3 = model.BuildTestMatchResult(3, 4)
+	err = database.CreateMatchResult(matchResult3)
+	assert.Nil(t, err)
+	updatedRankings, err = CalculateRankings(database, true)
+	assert.Nil(t, err)
+	rankings, err = database.GetAllRankings()
+	assert.Nil(t, err)
+	assert.Equal(t, updatedRankings, rankings)
+	if assert.Equal(t, 6, len(rankings)) {
+		assert.Equal(t, 4, rankings[0].TeamId)
+		assert.Equal(t, 1, rankings[0].PreviousRank)
+		assert.Equal(t, 5, rankings[1].TeamId)
+		assert.Equal(t, 2, rankings[1].PreviousRank)
+		assert.Equal(t, 1, rankings[2].TeamId)
+		assert.Equal(t, 4, rankings[2].PreviousRank)
+		assert.Equal(t, 3, rankings[3].TeamId)
+		assert.Equal(t, 5, rankings[3].PreviousRank)
+		assert.Equal(t, 6, rankings[4].TeamId)
+		assert.Equal(t, 3, rankings[4].PreviousRank)
+		assert.Equal(t, 2, rankings[5].TeamId)
+		assert.Equal(t, 6, rankings[5].PreviousRank)
 	}
 }