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| 1 | +import { BailianError, ExitCode, type LocalizedText } from "bailian-cli-core"; |
| 2 | +import { parseModelStreamEvent } from "./model-stream.ts"; |
| 3 | + |
| 4 | +export interface ChatStreamUpdate { |
| 5 | + content: string; |
| 6 | + reasoning: string; |
| 7 | +} |
| 8 | + |
| 9 | +export interface ChatStreamToolCall { |
| 10 | + id: string; |
| 11 | + type: "function"; |
| 12 | + function: { name: string; arguments: string }; |
| 13 | +} |
| 14 | + |
| 15 | +export interface ChatStreamResult { |
| 16 | + content: string; |
| 17 | + tool_calls?: ChatStreamToolCall[]; |
| 18 | + finish_reason: string | null; |
| 19 | +} |
| 20 | + |
| 21 | +interface PendingToolCall { |
| 22 | + id: string; |
| 23 | + name: string; |
| 24 | + arguments: string; |
| 25 | +} |
| 26 | + |
| 27 | +function asRecord(value: unknown): Record<string, unknown> | undefined { |
| 28 | + return value !== null && typeof value === "object" && !Array.isArray(value) |
| 29 | + ? (value as Record<string, unknown>) |
| 30 | + : undefined; |
| 31 | +} |
| 32 | + |
| 33 | +/** Aggregate Chat Completions SSE deltas with completion and tool-call checks. */ |
| 34 | +export function createChatCompletionStreamAccumulator(localize: (text: LocalizedText) => string): { |
| 35 | + readonly completed: boolean; |
| 36 | + accept(event: { event?: string; data: string }): ChatStreamUpdate; |
| 37 | + finish(): ChatStreamResult; |
| 38 | +} { |
| 39 | + let completed = false; |
| 40 | + let content = ""; |
| 41 | + let finishReason: string | null = null; |
| 42 | + const toolCalls = new Map<number, PendingToolCall>(); |
| 43 | + |
| 44 | + const missingIndexError = () => |
| 45 | + new BailianError( |
| 46 | + localize({ |
| 47 | + "en-US": "Tool call delta is missing a valid index.", |
| 48 | + "zh-CN": "工具调用增量缺少有效的 index。", |
| 49 | + }), |
| 50 | + ExitCode.GENERAL, |
| 51 | + ); |
| 52 | + |
| 53 | + const conflictingIdError = () => |
| 54 | + new BailianError( |
| 55 | + localize({ |
| 56 | + "en-US": "Tool call index returned conflicting ids.", |
| 57 | + "zh-CN": "同一工具调用 index 返回了不同的 id。", |
| 58 | + }), |
| 59 | + ExitCode.GENERAL, |
| 60 | + ); |
| 61 | + |
| 62 | + const acceptToolCallDelta = (fragment: unknown): void => { |
| 63 | + const delta = asRecord(fragment); |
| 64 | + if (!delta) throw missingIndexError(); |
| 65 | + |
| 66 | + const index = delta.index; |
| 67 | + if (typeof index !== "number" || !Number.isInteger(index) || index < 0) { |
| 68 | + throw missingIndexError(); |
| 69 | + } |
| 70 | + |
| 71 | + const entry = toolCalls.get(index) ?? { id: "", name: "", arguments: "" }; |
| 72 | + if (typeof delta.id === "string" && delta.id) { |
| 73 | + if (entry.id && entry.id !== delta.id) throw conflictingIdError(); |
| 74 | + entry.id = delta.id; |
| 75 | + } |
| 76 | + |
| 77 | + const functionDelta = asRecord(delta.function); |
| 78 | + if (typeof functionDelta?.name === "string") entry.name += functionDelta.name; |
| 79 | + if (typeof functionDelta?.arguments === "string") entry.arguments += functionDelta.arguments; |
| 80 | + |
| 81 | + toolCalls.set(index, entry); |
| 82 | + }; |
| 83 | + |
| 84 | + return { |
| 85 | + get completed() { |
| 86 | + return completed; |
| 87 | + }, |
| 88 | + |
| 89 | + accept(event: { event?: string; data: string }): ChatStreamUpdate { |
| 90 | + let contentDelta = ""; |
| 91 | + let reasoningDelta = ""; |
| 92 | + |
| 93 | + if (event.data === "[DONE]") { |
| 94 | + completed = true; |
| 95 | + return { content: "", reasoning: "" }; |
| 96 | + } |
| 97 | + |
| 98 | + const parsed = parseModelStreamEvent(event); |
| 99 | + if (!parsed) return { content: "", reasoning: "" }; |
| 100 | + |
| 101 | + const choices = Array.isArray(parsed.choices) ? parsed.choices : []; |
| 102 | + for (const choiceValue of choices) { |
| 103 | + const choice = asRecord(choiceValue); |
| 104 | + if (!choice) continue; |
| 105 | + |
| 106 | + const delta = asRecord(choice.delta); |
| 107 | + if (delta) { |
| 108 | + if (typeof delta.reasoning_content === "string" && delta.reasoning_content) { |
| 109 | + reasoningDelta += delta.reasoning_content; |
| 110 | + } |
| 111 | + if (typeof delta.content === "string" && delta.content) { |
| 112 | + contentDelta += delta.content; |
| 113 | + content += delta.content; |
| 114 | + } |
| 115 | + if (Array.isArray(delta.tool_calls)) { |
| 116 | + for (const fragment of delta.tool_calls) acceptToolCallDelta(fragment); |
| 117 | + } |
| 118 | + } |
| 119 | + |
| 120 | + if (typeof choice.finish_reason === "string" && choice.finish_reason) { |
| 121 | + if (finishReason === null) finishReason = choice.finish_reason; |
| 122 | + completed = true; |
| 123 | + } |
| 124 | + } |
| 125 | + |
| 126 | + return { content: contentDelta, reasoning: reasoningDelta }; |
| 127 | + }, |
| 128 | + |
| 129 | + finish(): ChatStreamResult { |
| 130 | + if (!completed) { |
| 131 | + throw new BailianError( |
| 132 | + localize({ |
| 133 | + "en-US": |
| 134 | + "Stream disconnected before completion: stream closed before [DONE] or finish_reason.", |
| 135 | + "zh-CN": "流在完成前断开：未收到 [DONE] 或 finish_reason。", |
| 136 | + }), |
| 137 | + ExitCode.GENERAL, |
| 138 | + ); |
| 139 | + } |
| 140 | + |
| 141 | + const sorted = [...toolCalls.entries()] |
| 142 | + .sort(([left], [right]) => left - right) |
| 143 | + .map(([, call]) => call); |
| 144 | + |
| 145 | + const seenIds = new Set<string>(); |
| 146 | + const tool_calls: ChatStreamToolCall[] = []; |
| 147 | + for (const call of sorted) { |
| 148 | + if (!call.id || !call.name) { |
| 149 | + throw new BailianError( |
| 150 | + localize({ |
| 151 | + "en-US": "Tool call is missing a required id or function name.", |
| 152 | + "zh-CN": "工具调用缺少必需的 id 或 function.name。", |
| 153 | + }), |
| 154 | + ExitCode.GENERAL, |
| 155 | + ); |
| 156 | + } |
| 157 | + if (seenIds.has(call.id)) { |
| 158 | + throw new BailianError( |
| 159 | + localize({ |
| 160 | + "en-US": "Duplicate tool call id across indexes.", |
| 161 | + "zh-CN": "不同工具调用 index 返回了重复的 id。", |
| 162 | + }), |
| 163 | + ExitCode.GENERAL, |
| 164 | + ); |
| 165 | + } |
| 166 | + seenIds.add(call.id); |
| 167 | + tool_calls.push({ |
| 168 | + id: call.id, |
| 169 | + type: "function", |
| 170 | + function: { name: call.name, arguments: call.arguments }, |
| 171 | + }); |
| 172 | + } |
| 173 | + |
| 174 | + const result: ChatStreamResult = { |
| 175 | + content, |
| 176 | + finish_reason: finishReason, |
| 177 | + }; |
| 178 | + if (tool_calls.length > 0) result.tool_calls = tool_calls; |
| 179 | + return result; |
| 180 | + }, |
| 181 | + }; |
| 182 | +} |
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