feat(compare): add ModelStats type and aggregateModelStats

src/compare-stats.ts

@@ -0,0 +1,63 @@
+import type { ProjectSummary } from './types.js'
+
+export type ModelStats = {
+  model: string
+  calls: number
+  cost: number
+  outputTokens: number
+  inputTokens: number
+  cacheReadTokens: number
+  cacheWriteTokens: number
+  totalTurns: number
+  editTurns: number
+  oneShotTurns: number
+  retries: number
+  selfCorrections: number
+  firstSeen: string
+  lastSeen: string
+}
+
+export function aggregateModelStats(projects: ProjectSummary[]): ModelStats[] {
+  const byModel = new Map<string, ModelStats>()
+
+  const ensure = (model: string): ModelStats => {
+    let s = byModel.get(model)
+    if (!s) {
+      s = { model, calls: 0, cost: 0, outputTokens: 0, inputTokens: 0, cacheReadTokens: 0, cacheWriteTokens: 0, totalTurns: 0, editTurns: 0, oneShotTurns: 0, retries: 0, selfCorrections: 0, firstSeen: '', lastSeen: '' }
+      byModel.set(model, s)
+    }
+    return s
+  }
+
+  for (const project of projects) {
+    for (const session of project.sessions) {
+      for (const turn of session.turns) {
+        if (turn.assistantCalls.length === 0) continue
+        const primaryModel = turn.assistantCalls[0]!.model
+        if (primaryModel === '<synthetic>') continue
+
+        const ms = ensure(primaryModel)
+        ms.totalTurns++
+        if (turn.hasEdits) ms.editTurns++
+        if (turn.hasEdits && turn.retries === 0) ms.oneShotTurns++
+        ms.retries += turn.retries
+
+        for (const call of turn.assistantCalls) {
+          if (call.model === '<synthetic>') continue
+          const cs = call.model === primaryModel ? ms : ensure(call.model)
+          cs.calls++
+          cs.cost += call.costUSD
+          cs.outputTokens += call.usage.outputTokens
+          cs.inputTokens += call.usage.inputTokens
+          cs.cacheReadTokens += call.usage.cacheReadInputTokens
+          cs.cacheWriteTokens += call.usage.cacheCreationInputTokens
+
+          if (!cs.firstSeen || call.timestamp < cs.firstSeen) cs.firstSeen = call.timestamp
+          if (!cs.lastSeen || call.timestamp > cs.lastSeen) cs.lastSeen = call.timestamp
+        }
+      }
+    }
+  }
+
+  return [...byModel.values()].sort((a, b) => b.cost - a.cost)
+}