/**
 * Git worktree list parser — pure functions, no pi SDK dependencies.
 *
 * Parses raw `git worktree list` output into structured entries.
 */

import path from "path";

// ─── Type Definitions ──────────────────────────────────────────────

/** A single worktree entry parsed from `git worktree list`. */
export interface WorktreeEntry {
	/** Full path to the worktree directory. */
	path: string;
	/** Short commit hash checked out in this worktree. */
	commit: string;
	/** Branch name, or "(detached)" for detached HEAD. */
	branch: string;
	/** Whether this worktree is the current working directory. */
	isCurrent: boolean;
}

// ─── Parser ────────────────────────────────────────────────────────

/**
 * Parse raw `git worktree list` output into structured entries.
 *
 * Expected format (whitespace-separated):
 *   /path/to/repo    abc1234 [main]
 *   /tmp/feature-x   def5678 [feature-x]
 *   /tmp/detached    fedcba HEAD
 *
 * @param rawOutput - Raw stdout from `git worktree list`
 * @param currentDir - Current working directory for comparison
 * @returns Array of parsed worktree entries
 */
export function parseWorktreeList(rawOutput: string, currentDir: string): WorktreeEntry[] {
	const lines = rawOutput.trim().split("\n").filter((line) => line.trim());

	return lines.map((line) => {
		// Split on whitespace: path, commit_hash, [branch] or HEAD
		const parts = line.trim().split(/\s+/);

		// Guard against malformed lines — need at least 3 tokens (path, commit, branch/HEAD)
		if (parts.length < 3) {
			return null;
		}

		const worktreePath = parts[0];
		const commitHash = parts[1];
		const branchRaw = parts.slice(2).join(" ");

		// Validate: branch must be in brackets [name] or HEAD for detached
		if (!branchRaw.match(/^\[.+\]$/) && !branchRaw.match(/^HEAD$/)) {
			return null;
		}

		// Extract branch name from brackets, or mark as detached
		const bracketMatch = branchRaw.match(/^\[(.+)\]$/);
		const branchName = bracketMatch ? bracketMatch[1] : "(detached)";

		return {
			path: worktreePath,
			commit: commitHash,
			branch: branchName,
			isCurrent: path.resolve(worktreePath) === path.resolve(currentDir),
		};
	}).filter((entry): entry is WorktreeEntry => entry !== null);
}