import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
import { buildSummaryInstructions } from "./prompts.js";
import type { CompactionState } from "./state.js";
import type { CompactionMode, CurrentFocus } from "./types.js";
import { CONTINUATION_PROMPT } from "./types.js";

export interface LifecycleOptions {
	/** Whether to send the continuation prompt after successful auto-compaction. */
	sendContinuation?: boolean;
	/** Optional callback to persist state after onComplete/onError update lastCompactTokens. */
	persist?: () => void | Promise<void>;
}

/**
 * Unified compaction lifecycle for both manual and auto triggers.
 *
 * Handles state setup, ctx.compact() call, and onComplete/onError cleanup.
 * This replaces the 4 duplicated cleanup blocks that existed before.
 */
export function executeCompaction(
	mode: CompactionMode,
	focus: CurrentFocus,
	state: CompactionState,
	ctx: Parameters<Parameters<ExtensionAPI["on"]>[1]>[1],
	pi: ExtensionAPI,
	options?: LifecycleOptions,
): void {
	state.selectedMode = mode;
	state.isCompacting = true;

	ctx.compact({
		customInstructions: buildSummaryInstructions(mode, focus),
		onComplete: () => {
			state.isCompacting = false;
			state.selectedMode = null;
			state.lastTriggerAuto = false;
			state.lastCompactTime = state.lastCompaction?.timestamp ?? Date.now();
			state.echoInjected = false;
			const postUsage = ctx.getContextUsage();
			if (postUsage && typeof postUsage.tokens === "number") {
				state.lastCompactTokens = postUsage.tokens;
			}
			options?.persist?.();
			if (options?.sendContinuation) {
				pi.sendUserMessage(CONTINUATION_PROMPT, { deliverAs: "followUp" });
			}
		},
		onError: (error) => {
			state.isCompacting = false;
			state.selectedMode = null;
			state.lastTriggerAuto = false;
			state.lastCompactTokens = 0;
			state.echoInjected = false;
			state.clearPendingCompaction();
			options?.persist?.();
			if (ctx.hasUI) {
				ctx.ui.notify(`Compact+ compaction failed: ${error.message}`, "error");
			}
		},
	});
}