feat: add Glicko2 rating system support

2026-03-31 03:38:16 -07:00
parent cfd36d375c
commit e3137085c8
1 changed files with 452 additions and 0 deletions
@@ -0,0 +1,452 @@
+import type { PrismaClient } from '@prisma/client';
+
+// Import Glicko2 using require to avoid TypeScript issues with the module declaration
+const Glicko2 = require('glicko2').Glicko2;
+
+/**
+ * Glicko2 Rating Utilities
+ * 
+ * Provides functions for calculating Glicko2 ratings
+ * Glicko2 is a rating system that accounts for rating reliability (deviation)
+ */
+
+// Glicko2 settings
+const settings = {
+  tau: 0.5, // constrains volatility
+  rating: 1500,
+  rd: 350,
+  vol: 0.06
+};
+
+/**
+ * Create a new Glicko2 instance
+ * @returns Glicko2 instance
+ */
+export function createGlicko2Instance() {
+  return new Glicko2(settings);
+}
+
+/**
+ * Create a new Glicko2 player
+ * @returns Glicko2 player object
+ */
+export function createGlicko2Player() {
+  const glicko = createGlicko2Instance();
+  return glicko.makePlayer();
+}
+
+/**
+ * Convert Prisma Glicko2 rating to Glicko2 player
+ * @param ratingRecord Prisma Glicko2Rating record
+ * @returns Glicko2 player object
+ */
+export function toGlicko2Player(ratingRecord: {
+  rating: number;
+  deviation: number;
+  volatility: number;
+}) {
+  const glicko = new Glicko2(settings);
+  return glicko.makePlayer(
+    ratingRecord.rating,
+    ratingRecord.deviation,
+    ratingRecord.volatility
+  );
+}
+
+/**
+ * Convert Glicko2 player to Prisma Glicko2 rating format
+ * @param player Glicko2 player object
+ * @returns Object with rating, deviation, and volatility
+ */
+export function fromGlicko2Player(player: any): {
+  rating: number;
+  deviation: number;
+  volatility: number;
+} {
+  return {
+    rating: player.getRating(),
+    deviation: player.getRd(),
+    volatility: player.getVol()
+  };
+}
+
+/**
+ * Calculate Glicko2 ratings for a match
+ * @param team1Players Array of Glicko2 players for team 1
+ * @param team2Players Array of Glicko2 players for team 2
+ * @param team1Won Whether team 1 won
+ * @param team2Won Whether team 2 won
+ * @param isTie Whether the match was a tie
+ * @returns Updated player ratings
+ */
+export function calculateGlicko2Ratings(
+  team1Players: any[],
+  team2Players: any[],
+  team1Won: boolean,
+  team2Won: boolean,
+  isTie: boolean
+): { player: any; newRating: number; newDeviation: number; newVolatility: number }[] {
+  const glicko = new Glicko2(settings);
+  
+  // Convert players to Glicko2 format if needed
+  const processedTeam1 = team1Players.map(p => 
+    typeof p.getRating === 'function' ? p : glicko.makePlayer(p.rating, p.deviation, p.volatility)
+  );
+  const processedTeam2 = team2Players.map(p => 
+    typeof p.getRating === 'function' ? p : glicko.makePlayer(p.rating, p.deviation, p.volatility)
+  );
+
+  // Create matches in Glicko2 format
+  // Glicko2 expects matches as [player1, player2, outcome]
+  // where outcome is 1 for player1 win, 0.5 for draw, 0 for player2 win
+  const matches: [any, any, number][] = [];
+  
+  // For team matches, we create individual matchups between players
+  // This is a simplified approach - in practice, you might want a more sophisticated model
+  for (const p1 of processedTeam1) {
+    for (const p2 of processedTeam2) {
+      let outcome: number;
+      if (isTie) {
+        outcome = 0.5; // Draw
+      } else if (team1Won) {
+        outcome = 1; // Team 1 player wins
+      } else {
+        outcome = 0; // Team 2 player wins
+      }
+      matches.push([p1, p2, outcome]);
+    }
+  }
+
+  // Update ratings
+  glicko.updateRatings(matches);
+
+  // Return updated players
+  return [
+    ...processedTeam1.map(p => ({
+      player: p,
+      newRating: p.getRating(),
+      newDeviation: p.getRd(),
+      newVolatility: p.getVol()
+    })),
+    ...processedTeam2.map(p => ({
+      player: p,
+      newRating: p.getRating(),
+      newDeviation: p.getRd(),
+      newVolatility: p.getVol()
+    }))
+  ];
+}
+
+/**
+ * Update player Glicko2 statistics after a match
+ * @param prisma Prisma client instance
+ * @param matchData Match data with player IDs and results
+ * @returns Promise<void>
+ */
+export async function updateGlicko2Ratings(
+  prisma: PrismaClient,
+  matchData: {
+    team1Players: number[];
+    team2Players: number[];
+    team1Won: boolean;
+    team2Won: boolean;
+    isTie: boolean;
+  }
+): Promise<void> {
+  const { team1Players, team2Players, team1Won, team2Won, isTie } = matchData;
+
+  // Get current ratings for all players
+  const playerRecords = new Map<number, {
+    rating: number;
+    deviation: number;
+    volatility: number;
+  }>();
+  
+  for (const playerId of [...team1Players, ...team2Players]) {
+    try {
+      const ratingRecord = await (prisma as any).glicko2Rating.findUnique({
+        where: { playerId },
+      });
+      
+      if (ratingRecord) {
+        playerRecords.set(playerId, {
+          rating: ratingRecord.rating,
+          deviation: ratingRecord.deviation,
+          volatility: ratingRecord.volatility
+        });
+      } else {
+        playerRecords.set(playerId, {
+          rating: 1500,
+          deviation: 350,
+          volatility: 0.06
+        });
+      }
+    } catch (error) {
+      // If the model doesn't exist yet, use default
+      playerRecords.set(playerId, {
+        rating: 1500,
+        deviation: 350,
+        volatility: 0.06
+      });
+    }
+  }
+
+  // Convert to Glicko2 players
+  const glicko = new Glicko2(settings);
+  const team1GlickoPlayers = team1Players.map(id => {
+    const record = playerRecords.get(id)!;
+    return glicko.makePlayer(record.rating, record.deviation, record.volatility);
+  });
+  const team2GlickoPlayers = team2Players.map(id => {
+    const record = playerRecords.get(id)!;
+    return glicko.makePlayer(record.rating, record.deviation, record.volatility);
+  });
+
+  // Calculate new ratings
+  const updatedPlayers = calculateGlicko2Ratings(
+    team1GlickoPlayers,
+    team2GlickoPlayers,
+    team1Won,
+    team2Won,
+    isTie
+  );
+
+  // Update database
+  // The updatedPlayers array contains both teams, so we need to match them back to player IDs
+  let playerIndex = 0;
+  
+  for (const playerId of [...team1Players, ...team2Players]) {
+    const updated = updatedPlayers[playerIndex];
+    await (prisma as any).glicko2Rating.upsert({
+      where: { playerId },
+      update: {
+        rating: updated.newRating,
+        deviation: updated.newDeviation,
+        volatility: updated.newVolatility,
+        gamesPlayed: { increment: 1 },
+        wins: team1Players.includes(playerId) && team1Won ? { increment: 1 } : 
+              team2Players.includes(playerId) && team2Won ? { increment: 1 } : undefined,
+        losses: (team1Players.includes(playerId) && team2Won && !isTie) ||
+                (team2Players.includes(playerId) && team1Won && !isTie) ? { increment: 1 } : undefined,
+        draws: isTie ? { increment: 1 } : undefined,
+        lastUpdated: new Date(),
+      },
+      create: {
+        playerId,
+        rating: updated.newRating,
+        deviation: updated.newDeviation,
+        volatility: updated.newVolatility,
+        gamesPlayed: 1,
+        wins: team1Players.includes(playerId) && team1Won ? 1 : 
+              team2Players.includes(playerId) && team2Won ? 1 : 0,
+        losses: (team1Players.includes(playerId) && team2Won && !isTie) ||
+                (team2Players.includes(playerId) && team1Won && !isTie) ? 1 : 0,
+        draws: isTie ? 1 : 0,
+        lastUpdated: new Date(),
+      },
+    });
+    playerIndex++;
+  }
+}
+
+/**
+ * Recalculate all Glicko2 ratings from match history
+ * @param prisma Prisma client instance
+ * @returns Object with counts of affected records
+ */
+export async function recalculateAllGlicko2(prisma: PrismaClient) {
+  // Get all matches in chronological order
+  const matches = await prisma.match.findMany({
+    orderBy: { playedAt: 'asc' },
+    include: {
+      team1P1: true,
+      team1P2: true,
+      team2P1: true,
+      team2P2: true,
+    },
+  });
+
+  // Reset all Glicko2 ratings
+  await (prisma as any).glicko2Rating.updateMany({
+    data: {
+      rating: 1500,
+      deviation: 350,
+      volatility: 0.06,
+      gamesPlayed: 0,
+      wins: 0,
+      losses: 0,
+      draws: 0,
+    },
+  });
+
+  // Initialize in-memory tracking
+  const playerRatings = new Map<number, {
+    rating: number;
+    deviation: number;
+    volatility: number;
+  }>();
+
+  // Initialize Glicko2 system
+  const glicko = new Glicko2(settings);
+
+  // Process each match
+  for (const match of matches) {
+    const { team1P1, team1P2, team2P1, team2P2, team1Score, team2Score } = match;
+
+    // Get current ratings
+    const getOrCreatePlayer = (playerId: number) => {
+      if (!playerRatings.has(playerId)) {
+        playerRatings.set(playerId, {
+          rating: 1500,
+          deviation: 350,
+          volatility: 0.06
+        });
+      }
+      const record = playerRatings.get(playerId)!;
+      return glicko.makePlayer(record.rating, record.deviation, record.volatility);
+    };
+
+    const p1 = getOrCreatePlayer(team1P1.id);
+    const p2 = getOrCreatePlayer(team1P2.id);
+    const p3 = getOrCreatePlayer(team2P1.id);
+    const p4 = getOrCreatePlayer(team2P2.id);
+
+    const team1Won = team1Score > team2Score;
+    const team2Won = team2Score > team1Score;
+    const isTie = team1Score === team2Score;
+
+    // Create matches
+    const matchesToUpdate: [any, any, number][] = [];
+    const outcome = isTie ? 0.5 : team1Won ? 1 : 0;
+    
+    // Create matchups between all players
+    [p1, p2].forEach(p1Player => {
+      [p3, p4].forEach(p2Player => {
+        matchesToUpdate.push([p1Player, p2Player, outcome]);
+      });
+    });
+
+    // Update ratings
+    glicko.updateRatings(matchesToUpdate);
+
+    // Update in-memory ratings
+    playerRatings.set(team1P1.id, {
+      rating: p1.getRating(),
+      deviation: p1.getRd(),
+      volatility: p1.getVol()
+    });
+    playerRatings.set(team1P2.id, {
+      rating: p2.getRating(),
+      deviation: p2.getRd(),
+      volatility: p2.getVol()
+    });
+    playerRatings.set(team2P1.id, {
+      rating: p3.getRating(),
+      deviation: p3.getRd(),
+      volatility: p3.getVol()
+    });
+    playerRatings.set(team2P2.id, {
+      rating: p4.getRating(),
+      deviation: p4.getRd(),
+      volatility: p4.getVol()
+    });
+
+    // Update database records
+    await (prisma as any).glicko2Rating.upsert({
+      where: { playerId: team1P1.id },
+      update: {
+        rating: p1.getRating(),
+        deviation: p1.getRd(),
+        volatility: p1.getVol(),
+        gamesPlayed: { increment: 1 },
+        wins: team1Won ? { increment: 1 } : undefined,
+        losses: !team1Won && !isTie ? { increment: 1 } : undefined,
+        draws: isTie ? { increment: 1 } : undefined,
+      },
+      create: {
+        playerId: team1P1.id,
+        rating: p1.getRating(),
+        deviation: p1.getRd(),
+        volatility: p1.getVol(),
+        gamesPlayed: 1,
+        wins: team1Won ? 1 : 0,
+        losses: !team1Won && !isTie ? 1 : 0,
+        draws: isTie ? 1 : 0,
+      },
+    });
+
+    await (prisma as any).glicko2Rating.upsert({
+      where: { playerId: team1P2.id },
+      update: {
+        rating: p2.getRating(),
+        deviation: p2.getRd(),
+        volatility: p2.getVol(),
+        gamesPlayed: { increment: 1 },
+        wins: team1Won ? { increment: 1 } : undefined,
+        losses: !team1Won && !isTie ? { increment: 1 } : undefined,
+        draws: isTie ? { increment: 1 } : undefined,
+      },
+      create: {
+        playerId: team1P2.id,
+        rating: p2.getRating(),
+        deviation: p2.getRd(),
+        volatility: p2.getVol(),
+        gamesPlayed: 1,
+        wins: team1Won ? 1 : 0,
+        losses: !team1Won && !isTie ? 1 : 0,
+        draws: isTie ? 1 : 0,
+      },
+    });
+
+    await (prisma as any).glicko2Rating.upsert({
+      where: { playerId: team2P1.id },
+      update: {
+        rating: p3.getRating(),
+        deviation: p3.getRd(),
+        volatility: p3.getVol(),
+        gamesPlayed: { increment: 1 },
+        wins: team2Won ? { increment: 1 } : undefined,
+        losses: !team2Won && !isTie ? { increment: 1 } : undefined,
+        draws: isTie ? { increment: 1 } : undefined,
+      },
+      create: {
+        playerId: team2P1.id,
+        rating: p3.getRating(),
+        deviation: p3.getRd(),
+        volatility: p3.getVol(),
+        gamesPlayed: 1,
+        wins: team2Won ? 1 : 0,
+        losses: !team2Won && !isTie ? 1 : 0,
+        draws: isTie ? 1 : 0,
+      },
+    });
+
+    await (prisma as any).glicko2Rating.upsert({
+      where: { playerId: team2P2.id },
+      update: {
+        rating: p4.getRating(),
+        deviation: p4.getRd(),
+        volatility: p4.getVol(),
+        gamesPlayed: { increment: 1 },
+        wins: team2Won ? { increment: 1 } : undefined,
+        losses: !team2Won && !isTie ? { increment: 1 } : undefined,
+        draws: isTie ? { increment: 1 } : undefined,
+      },
+      create: {
+        playerId: team2P2.id,
+        rating: p4.getRating(),
+        deviation: p4.getRd(),
+        volatility: p4.getVol(),
+        gamesPlayed: 1,
+        wins: team2Won ? 1 : 0,
+        losses: !team2Won && !isTie ? 1 : 0,
+        draws: isTie ? 1 : 0,
+      },
+    });
+  }
+
+  return {
+    matchesProcessed: matches.length,
+    playersUpdated: playerRatings.size,
+  };
+}