import type { LlmStreamProgress, SessionEntry } from "../session";

type RunningProcesses = SessionEntry["processes"];

export type LoadingTextInput = {

progress: LlmStreamProgress | null;

processes?: RunningProcesses;

now: number;

};

const STALL_THRESHOLD_MS = 3000;

export function buildLoadingText(input: LoadingTextInput): string {

const { progress, processes, now } = input;

const processText = buildProcessLoadingText(processes, now);

if (processText) {

return processText;

}

if (!progress) {

return "Thinking...";

}

const startedAt = parseTimestamp(progress.startedAt);

if (startedAt === null) {

return "Thinking...";

}

const elapsedMs = Math.max(0, now - startedAt);

if (elapsedMs < STALL_THRESHOLD_MS) {

return "Thinking...";

}

const elapsedSeconds = Math.floor(elapsedMs / 1000);

const tokens = progress.formattedTokens || "0";

return `Thinking... (${elapsedSeconds}s) · ↓ ${tokens} tokens`;

}

function buildProcessLoadingText(processes: RunningProcesses | undefined, now: number): string | null {

if (!processes || processes.size === 0) {

return null;

}

const first = processes.values().next().value as { startTime: string; command: string } | undefined;

if (!first) {

return null;

}

return `(${formatElapsedTime(first.startTime, now)}) ${first.command}`;

}

function formatElapsedTime(startTimeIso: string, now: number): string {

const startTime = parseTimestamp(startTimeIso);

const elapsedMs = startTime === null ? 0 : Math.max(0, now - startTime);

const elapsedSeconds = Math.floor(elapsedMs / 1000);

const minutes = Math.floor(elapsedSeconds / 60);

const seconds = elapsedSeconds % 60;

if (minutes > 0) {

return `${minutes}m${seconds}s`;

}

return `${seconds}s`;

}

function parseTimestamp(value: string): number | null {

const parsed = Date.parse(value);

if (Number.isNaN(parsed)) {

return null;

}

return parsed;

}