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pi-web/src/server/sessions/sessionNameGenerator.ts
T

130 lines
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TypeScript

import type { Api, AssistantMessage, AssistantMessageEventStream, Context, Model, SimpleStreamOptions } from "@earendil-works/pi-ai";
import type { ModelRegistry } from "@earendil-works/pi-coding-agent";
const SESSION_NAME_TIMEOUT_MS = 10_000;
const SESSION_NAME_MAX_INPUT_CHARS = 4_000;
const SESSION_NAME_MAX_LENGTH = 60;
const FALLBACK_SESSION_NAME_MAX_WORDS = 6;
const PI_AI_COMPAT_MODULE = ["@earendil-works/pi-ai", "compat"].join("/");
interface SessionNameApiProvider {
streamSimple(model: Model<Api>, context: Context, options?: SimpleStreamOptions): AssistantMessageEventStream;
}
interface PiAiProviderRegistryModule {
getApiProvider?: (api: Api) => SessionNameApiProvider | undefined;
}
type ModuleImporter = (specifier: string) => Promise<unknown>;
let piAiProviderRegistryModulePromise: Promise<PiAiProviderRegistryModule> | undefined;
export async function generateShortSessionName<TApi extends Api>(modelRegistry: ModelRegistry, model: Model<TApi>, firstMessage: string): Promise<string | undefined> {
const providerRegistry = await getPiAiProviderRegistryModule();
const provider = providerRegistry.getApiProvider?.(model.api);
if (provider === undefined) return undefined;
const auth = await modelRegistry.getApiKeyAndHeaders(model);
if (!auth.ok) return undefined;
const stream = provider.streamSimple(
model,
{
systemPrompt: "Generate a concise title for a coding-agent chat session. Return only the title, with no quotes or punctuation wrapper.",
messages: [{
role: "user",
content: `Create a 2-6 word title for this request:\n\n${truncateInput(firstMessage)}`,
timestamp: Date.now(),
}],
},
{
maxTokens: 24,
reasoning: "minimal",
signal: AbortSignal.timeout(SESSION_NAME_TIMEOUT_MS),
...(auth.apiKey === undefined ? {} : { apiKey: auth.apiKey }),
...(auth.headers === undefined ? {} : { headers: auth.headers }),
},
);
let streamedText = "";
let finalMessage: AssistantMessage | undefined;
for await (const event of stream) {
if (event.type === "text_delta") streamedText += event.delta;
if (event.type === "done") finalMessage = event.message;
if (event.type === "error") return undefined;
}
return cleanSessionName(finalMessage === undefined ? streamedText : textFromAssistant(finalMessage));
}
export function fallbackSessionName(firstMessage: unknown): string | undefined {
if (typeof firstMessage !== "string") return undefined;
return cleanSessionName(firstMessage
.replace(/<skill name="[^"]+" location="[^"]+">[\s\S]*?<\/skill>/g, "")
.replace(/```[\s\S]*?```/g, " ")
.replace(/[`*_#[\](){}<>]/g, " ")
.split(/\s+/)
.filter(Boolean)
.slice(0, FALLBACK_SESSION_NAME_MAX_WORDS)
.join(" "));
}
export function cleanSessionName(value: string): string | undefined {
const title = (value.split("\n", 1)[0] ?? "")
.replace(/^\s*(title|session title)\s*:\s*/i, "")
.replace(/^\s*["'`]+|["'`.]+\s*$/g, "")
.replace(/\s+/g, " ")
.trim()
.slice(0, SESSION_NAME_MAX_LENGTH)
.trim();
return title === "" ? undefined : title;
}
async function getPiAiProviderRegistryModule(importer: ModuleImporter = (specifier) => import(specifier)): Promise<PiAiProviderRegistryModule> {
piAiProviderRegistryModulePromise ??= loadPiAiProviderRegistryModule(importer);
return piAiProviderRegistryModulePromise;
}
async function loadPiAiProviderRegistryModule(importer: ModuleImporter): Promise<PiAiProviderRegistryModule> {
const compatModule = await importOptionalPiAiModule(PI_AI_COMPAT_MODULE, importer);
if (hasGetApiProvider(compatModule)) return compatModule;
const rootModule = await importer("@earendil-works/pi-ai");
if (hasGetApiProvider(rootModule)) return rootModule;
return {};
}
async function importOptionalPiAiModule(specifier: string, importer: ModuleImporter): Promise<unknown> {
try {
return await importer(specifier);
} catch (error) {
if (isModuleUnavailableError(error)) return undefined;
throw error;
}
}
function hasGetApiProvider(moduleValue: unknown): moduleValue is PiAiProviderRegistryModule {
return typeof moduleValue === "object"
&& moduleValue !== null
&& "getApiProvider" in moduleValue
&& typeof moduleValue.getApiProvider === "function";
}
function isModuleUnavailableError(error: unknown): boolean {
if (!(error instanceof Error)) return false;
const code = "code" in error ? error.code : undefined;
return code === "ERR_MODULE_NOT_FOUND" || code === "ERR_PACKAGE_PATH_NOT_EXPORTED";
}
function textFromAssistant(message: AssistantMessage): string {
return message.content
.filter((part) => part.type === "text")
.map((part) => part.text)
.join("");
}
function truncateInput(value: string): string {
return value.length <= SESSION_NAME_MAX_INPUT_CHARS ? value : `${value.slice(0, SESSION_NAME_MAX_INPUT_CHARS)}…`;
}