feat: 添加gemini协议适配 (#125)

* feat: 添加gemini协议适配

* Remove unrelated local files from Gemini PR

src/services/api/gemini/streamAdapter.ts

@@ -0,0 +1,244 @@
+import type { BetaRawMessageStreamEvent } from '@anthropic-ai/sdk/resources/beta/messages/messages.mjs'
+import { randomUUID } from 'crypto'
+import type { GeminiPart, GeminiStreamChunk } from './types.js'
+
+export async function* adaptGeminiStreamToAnthropic(
+  stream: AsyncIterable<GeminiStreamChunk>,
+  model: string,
+): AsyncGenerator<BetaRawMessageStreamEvent, void> {
+  const messageId = `msg_${randomUUID().replace(/-/g, '').slice(0, 24)}`
+  let started = false
+  let stopped = false
+  let nextContentIndex = 0
+  let openTextLikeBlock:
+    | { index: number; type: 'text' | 'thinking' }
+    | null = null
+  let sawToolUse = false
+  let finishReason: string | undefined
+  let inputTokens = 0
+  let outputTokens = 0
+
+  for await (const chunk of stream) {
+    const usage = chunk.usageMetadata
+    if (usage) {
+      inputTokens = usage.promptTokenCount ?? inputTokens
+      outputTokens =
+        (usage.candidatesTokenCount ?? 0) + (usage.thoughtsTokenCount ?? 0)
+    }
+
+    if (!started) {
+      started = true
+      yield {
+        type: 'message_start',
+        message: {
+          id: messageId,
+          type: 'message',
+          role: 'assistant',
+          content: [],
+          model,
+          stop_reason: null,
+          stop_sequence: null,
+          usage: {
+            input_tokens: inputTokens,
+            output_tokens: 0,
+            cache_creation_input_tokens: 0,
+            cache_read_input_tokens: 0,
+          },
+        },
+      } as BetaRawMessageStreamEvent
+    }
+
+    const candidate = chunk.candidates?.[0]
+    const parts = candidate?.content?.parts ?? []
+
+    for (const part of parts) {
+      if (part.functionCall) {
+        if (openTextLikeBlock) {
+          yield {
+            type: 'content_block_stop',
+            index: openTextLikeBlock.index,
+          } as BetaRawMessageStreamEvent
+          openTextLikeBlock = null
+        }
+
+        sawToolUse = true
+        const toolIndex = nextContentIndex++
+        const toolId = `toolu_${randomUUID().replace(/-/g, '').slice(0, 24)}`
+        yield {
+          type: 'content_block_start',
+          index: toolIndex,
+          content_block: {
+            type: 'tool_use',
+            id: toolId,
+            name: part.functionCall.name || '',
+            input: {},
+          },
+        } as BetaRawMessageStreamEvent
+
+        if (part.thoughtSignature) {
+          yield {
+            type: 'content_block_delta',
+            index: toolIndex,
+            delta: {
+              type: 'signature_delta',
+              signature: part.thoughtSignature,
+            },
+          } as BetaRawMessageStreamEvent
+        }
+
+        if (part.functionCall.args && Object.keys(part.functionCall.args).length > 0) {
+          yield {
+            type: 'content_block_delta',
+            index: toolIndex,
+            delta: {
+              type: 'input_json_delta',
+              partial_json: JSON.stringify(part.functionCall.args),
+            },
+          } as BetaRawMessageStreamEvent
+        }
+
+        yield {
+          type: 'content_block_stop',
+          index: toolIndex,
+        } as BetaRawMessageStreamEvent
+        continue
+      }
+
+      const textLikeType = getTextLikeBlockType(part)
+      if (textLikeType) {
+        if (!openTextLikeBlock || openTextLikeBlock.type !== textLikeType) {
+          if (openTextLikeBlock) {
+            yield {
+              type: 'content_block_stop',
+              index: openTextLikeBlock.index,
+            } as BetaRawMessageStreamEvent
+          }
+
+          openTextLikeBlock = {
+            index: nextContentIndex++,
+            type: textLikeType,
+          }
+
+          yield {
+            type: 'content_block_start',
+            index: openTextLikeBlock.index,
+            content_block:
+              textLikeType === 'thinking'
+                ? {
+                    type: 'thinking',
+                    thinking: '',
+                    signature: '',
+                  }
+                : {
+                    type: 'text',
+                    text: '',
+                  },
+          } as BetaRawMessageStreamEvent
+        }
+
+        if (part.text) {
+          yield {
+            type: 'content_block_delta',
+            index: openTextLikeBlock.index,
+            delta:
+              textLikeType === 'thinking'
+                ? {
+                    type: 'thinking_delta',
+                    thinking: part.text,
+                  }
+                : {
+                    type: 'text_delta',
+                    text: part.text,
+                  },
+          } as BetaRawMessageStreamEvent
+        }
+
+        if (part.thoughtSignature) {
+          yield {
+            type: 'content_block_delta',
+            index: openTextLikeBlock.index,
+            delta: {
+              type: 'signature_delta',
+              signature: part.thoughtSignature,
+            },
+          } as BetaRawMessageStreamEvent
+        }
+
+        continue
+      }
+
+      if (part.thoughtSignature && openTextLikeBlock) {
+        yield {
+          type: 'content_block_delta',
+          index: openTextLikeBlock.index,
+          delta: {
+            type: 'signature_delta',
+            signature: part.thoughtSignature,
+          },
+        } as BetaRawMessageStreamEvent
+      }
+    }
+
+    if (candidate?.finishReason) {
+      finishReason = candidate.finishReason
+    }
+  }
+
+  if (!started) {
+    return
+  }
+
+  if (openTextLikeBlock) {
+    yield {
+      type: 'content_block_stop',
+      index: openTextLikeBlock.index,
+    } as BetaRawMessageStreamEvent
+  }
+
+  if (!stopped) {
+    yield {
+      type: 'message_delta',
+      delta: {
+        stop_reason: mapGeminiFinishReason(finishReason, sawToolUse),
+        stop_sequence: null,
+      },
+      usage: {
+        output_tokens: outputTokens,
+      },
+    } as BetaRawMessageStreamEvent
+
+    yield {
+      type: 'message_stop',
+    } as BetaRawMessageStreamEvent
+    stopped = true
+  }
+}
+
+function getTextLikeBlockType(
+  part: GeminiPart,
+): 'text' | 'thinking' | null {
+  if (typeof part.text !== 'string') {
+    return null
+  }
+  return part.thought ? 'thinking' : 'text'
+}
+
+function mapGeminiFinishReason(
+  reason: string | undefined,
+  sawToolUse: boolean,
+): string {
+  switch (reason) {
+    case 'MAX_TOKENS':
+      return 'max_tokens'
+    case 'STOP':
+    case 'FINISH_REASON_UNSPECIFIED':
+    case 'SAFETY':
+    case 'RECITATION':
+    case 'BLOCKLIST':
+    case 'PROHIBITED_CONTENT':
+    case 'SPII':
+    case 'MALFORMED_FUNCTION_CALL':
+    default:
+      return sawToolUse ? 'tool_use' : 'end_turn'
+  }
+}