/** Final-output helpers for detached runs. */

import type { RunStatus, StepOutput, StepStatus, TeamStepSpec } from "./types.ts";

export const FINAL_INLINE_PREVIEW_CHARS = 6000;

interface StepFinalArtifactInput {
	runId: string;
	objective: string;
	step: TeamStepSpec;
	status: StepStatus;
	startedAt: string | undefined;
	endedAt: string;
	text: string;
	assistantFinals: string[];
}

export function buildStepFinalArtifact(input: StepFinalArtifactInput): string {
	return [
		"# agent_team step final",
		"",
		`runId: ${input.runId}`,
		`objective: ${input.objective}`,
		`stepId: ${input.step.id}`,
		`status: ${input.status}`,
		`agentRef: ${input.step.agent.ref}`,
		`agentSource: ${input.step.agent.source}`,
		`startedAt: ${input.startedAt ?? ""}`,
		`endedAt: ${input.endedAt}`,
		"",
		formatStepFinalBody(input.text, input.assistantFinals),
	].join("\n");
}

function formatStepFinalBody(text: string, assistantFinals: string[]): string {
	if (assistantFinals.length === 1) return assistantFinals[0] ?? "";
	if (assistantFinals.length > 1) return formatAssistantFinalMessages(assistantFinals);
	return fallbackFinalText(text);
}

export function formatAssistantFinalMessages(texts: string[]): string {
	return texts.map((text, index) => [`## Assistant final ${index + 1}`, "", text].join("\n")).join("\n\n");
}

function fallbackFinalText(text: string): string {
	return ["## Final text", "", text].join("\n");
}

export function boundedFinalPreview(text: string): string {
	if (text.length <= FINAL_INLINE_PREVIEW_CHARS) return text;
	return `${text.slice(0, FINAL_INLINE_PREVIEW_CHARS)}\n\n[agent_team preview truncated; full final is in the artifact file.]`;
}

export function boundedTextPreview(text: string, maxBytes: number): string {
	if (Buffer.byteLength(text, "utf8") <= maxBytes) return text;
	const suffix = "\n\n[agent_team preview truncated by maxBytes.]";
	const budget = Math.max(1, maxBytes - Buffer.byteLength(suffix, "utf8"));
	return `${utf8Prefix(text, budget)}${suffix}`;
}

export function boundedStepOutput(output: StepOutput, maxBytes: number): StepOutput {
	if (output.text === undefined) return output;
	return { ...output, text: boundedTextPreview(output.text, maxBytes) };
}

function utf8Prefix(text: string, maxBytes: number): string {
	let bytes = 0;
	let end = 0;
	for (const char of text) {
		const next = Buffer.byteLength(char, "utf8");
		if (bytes + next > maxBytes) break;
		bytes += next;
		end += char.length;
	}
	return text.slice(0, end);
}

export function isTerminalStepStatus(status: StepStatus): boolean {
	return status === "succeeded" || status === "failed" || status === "blocked" || status === "timed_out" || status === "canceled";
}

export function isTerminalRunStatus(status: RunStatus): boolean {
	return status === "succeeded" || status === "mixed" || status === "failed" || status === "canceled" || status === "expired";
}