// commit-emission.ts — shared commit-emission shim
//
// Provides a single performCommit function that routes commit emission
// through either bypass (execSync — byte-identical to upstream pi-committer)
// or review (write message file + return pending) based on the mode argument.
//
// This module imports ONLY node builtins (child_process, fs, path) — zero
// project imports → no circular dependency risk, safe for worker fork.

import { execSync } from "node:child_process";
import { writeFileSync } from "node:fs";
import * as path from "node:path";

// ---------------------------------------------------------------------------
// Types
// ---------------------------------------------------------------------------

export type CommitMode = "review" | "bypass";

export interface CommitEmissionContext {
	/** Repository working directory. */
	dir: string;
	/** Final commit message (already validated). */
	message: string;
}

export interface CommitEmissionResult {
	/** true if the commit emission succeeded (committed OR handed off). */
	success: boolean;
	/** Commit hash. Present only on bypass success (committed). */
	hash?: string;
	/** true in review-mode — commit handed off to the model. */
	pending?: boolean;
	/** Path to the written message file (review-mode only). */
	messageFile?: string;
}

// ---------------------------------------------------------------------------
// performCommit
// ---------------------------------------------------------------------------

/**
 * Emit a commit in the given mode.
 *
 * - bypass: execSync("git commit -F -") — byte-identical to upstream pi-committer.
 * - review: write message to .git/gentle_committer_pending_msg, return pending.
 *
 * SYNCHRONOUS — both branches complete synchronously (execSync or writeFileSync).
 * No async needed; keeping it sync avoids touching call-site signatures.
 */
export function performCommit(
	mode: CommitMode,
	ctx: CommitEmissionContext,
): CommitEmissionResult {
	if (mode === "review") {
		// Review branch: write the message file and return pending.
		// The caller (tool handler) returns a directive to the model, which then
		// runs `git commit -F <file>` through the bash tool so gentle-ai's gate fires.
		const messageFile = path.join(
			ctx.dir,
			".git",
			"gentle_committer_pending_msg",
		);
		try {
			writeFileSync(messageFile, ctx.message, "utf-8");
		} catch (err) {
			throw new Error(
				`Failed to write review-mode message file: ${
					err instanceof Error ? err.message : String(err)
				}`,
			);
		}
		return { success: true, pending: true, messageFile };
	}

	// Bypass branch: byte-identical to the original execSync call at index.ts:1641.
	// Hash extraction is left to the CALLER (getHeadHash), keeping performCommit
	// focused on emission only — matches the current inline pattern exactly.
	// (The execSync call args are unchanged; the try/catch only adds error context.)
	try {
		execSync("git commit -F -", {
			cwd: ctx.dir,
			encoding: "utf-8",
			stdio: ["pipe", "pipe", "ignore"],
			input: ctx.message,
		});
	} catch (err) {
		throw new Error(
			`Failed to commit (bypass mode): ${
				err instanceof Error ? err.message : String(err)
			}`,
		);
	}
	return { success: true };
}