fix(openai): fix duplicate cost tracking, local timezone day boundary, and add missing docstrings

- Remove duplicate addToTotalSessionCost call in message_stop handler
- Fix startOfDay() to use local date components instead of UTC
- Add JSDoc to all functions missing docstrings for 80%+ coverage

Signed-off-by: guunergooner <tongchao0923@gmail.com>

Author: guunergooner

src/services/api/openai/__tests__/queryModelOpenAI.test.ts

@@ -37,6 +37,7 @@ function makeMessageStart(overrides: Record<string, any> = {}): BetaRawMessageSt
   } as any
 }
 
+/** Build a content_block_start event for the given block type */
 function makeContentBlockStart(index: number, type: 'text' | 'tool_use' | 'thinking', extra: Record<string, any> = {}): BetaRawMessageStreamEvent {
   const block =
     type === 'text'
@@ -47,22 +48,27 @@ function makeContentBlockStart(index: number, type: 'text' | 'tool_use' | 'think
   return { type: 'content_block_start', index, content_block: { ...block, ...extra } } as any
 }
 
+/** Build a text_delta content_block_delta event */
 function makeTextDelta(index: number, text: string): BetaRawMessageStreamEvent {
   return { type: 'content_block_delta', index, delta: { type: 'text_delta', text } } as any
 }
 
+/** Build an input_json_delta content_block_delta event */
 function makeInputJsonDelta(index: number, json: string): BetaRawMessageStreamEvent {
   return { type: 'content_block_delta', index, delta: { type: 'input_json_delta', partial_json: json } } as any
 }
 
+/** Build a thinking_delta content_block_delta event */
 function makeThinkingDelta(index: number, thinking: string): BetaRawMessageStreamEvent {
   return { type: 'content_block_delta', index, delta: { type: 'thinking_delta', thinking } } as any
 }
 
+/** Build a content_block_stop event */
 function makeContentBlockStop(index: number): BetaRawMessageStreamEvent {
   return { type: 'content_block_stop', index } as any
 }
 
+/** Build a message_delta event with stop_reason and output_tokens */
 function makeMessageDelta(stopReason: string, outputTokens: number): BetaRawMessageStreamEvent {
   return {
     type: 'message_delta',
@@ -71,6 +77,7 @@ function makeMessageDelta(stopReason: string, outputTokens: number): BetaRawMess
   } as any
 }
 
+/** Build a message_stop event */
 function makeMessageStop(): BetaRawMessageStreamEvent {
   return { type: 'message_stop' } as any
 }

src/services/api/openai/__tests__/streamAdapter.test.ts

@@ -29,6 +29,7 @@ function makeChunk(overrides: Partial<ChatCompletionChunk> & any = {}): ChatComp
   } as ChatCompletionChunk
 }
 
+/** Collect all emitted Anthropic events from the stream adapter for assertion */
 async function collectEvents(chunks: ChatCompletionChunk[]) {
   const events: any[] = []
   for await (const event of adaptOpenAIStreamToAnthropic(mockStream(chunks), 'gpt-4o')) {

src/services/api/openai/index.ts

@@ -382,15 +382,6 @@ export async function* queryModelOpenAI(
         }
       }
 
-      // Track cost and token usage (matching the Anthropic path in claude.ts)
-      if (
-        event.type === 'message_stop' &&
-        usage.input_tokens + usage.output_tokens > 0
-      ) {
-        const costUSD = calculateUSDCost(openaiModel, usage as any)
-        addToTotalSessionCost(costUSD, usage as any, options.model)
-      }
-
       // Also yield as StreamEvent for real-time display (matching Anthropic path)
       yield {
         type: 'stream_event',

src/utils/formatBriefTimestamp.ts

@@ -76,6 +76,7 @@ function getLocale(): string | undefined {
   }
 }
 
+/** Return the epoch-ms of the start of the local calendar day for `d`. */
 function startOfDay(d: Date): number {
-  return Date.UTC(d.getUTCFullYear(), d.getUTCMonth(), d.getUTCDate())
+  return new Date(d.getFullYear(), d.getMonth(), d.getDate()).getTime()
 }