/**
 * Rule registry system
 */

import type { PruneRule } from "./types";

/**
 * Global registry of available pruning rules
 */
const ruleRegistry = new Map<string, PruneRule>();

/**
 * Register a pruning rule
 */
export function registerRule(rule: PruneRule): void {
	// Validate rule has required fields
	if (!rule.name) {
		throw new Error("Rule must have a name");
	}

	if (!rule.prepare && !rule.process) {
		throw new Error(`Rule "${rule.name}" must have at least one of: prepare, process`);
	}

	// Warn if duplicate (but allow override)
	if (ruleRegistry.has(rule.name)) {
		console.warn(`[pi-dcp] Overriding existing rule: ${rule.name}`);
	}

	ruleRegistry.set(rule.name, rule);
}

/**
 * Get rule by name
 */
export function getRule(name: string): PruneRule | undefined {
	return ruleRegistry.get(name);
}

/**
 * Resolve rule reference (string name or inline object)
 */
export function resolveRule(ruleRef: string | PruneRule): PruneRule {
	// If already an object, validate and return
	if (typeof ruleRef === "object") {
		if (!ruleRef.name) {
			throw new Error("Inline rule must have a name");
		}
		if (!ruleRef.prepare && !ruleRef.process) {
			throw new Error(`Inline rule "${ruleRef.name}" must have at least one of: prepare, process`);
		}
		return ruleRef;
	}

	// String reference - lookup in registry
	const rule = ruleRegistry.get(ruleRef);
	if (!rule) {
		throw new Error(`Rule not found: ${ruleRef}. Available rules: ${Array.from(ruleRegistry.keys()).join(", ")}`);
	}

	return rule;
}

/**
 * Get all registered rules
 */
export function getAllRules(): PruneRule[] {
	return Array.from(ruleRegistry.values());
}

/**
 * Get all registered rule names
 */
export function getRuleNames(): string[] {
	return Array.from(ruleRegistry.keys());
}