import type { ComplexityTier } from "../../shared/value-objects/complexity-tier.js";

export type RiskLevel = "low" | "medium" | "high";

export interface ComplexitySignals {
	taskCount: number;
	estimatedFilesAffected: number;
	newFilesCreated: number;
	modulesAffected: number;
	hasExternalIntegrations: boolean;
	requiresInvestigation: boolean;
	architectureImpact: boolean;
	unknownsSurfaced: number;
	riskLevel: RiskLevel;
}

export const classifyComplexity = (signals: ComplexitySignals): ComplexityTier => {
	// High risk forces SSS regardless of scope (security, auth, data integrity, public API)
	if (signals.riskLevel === "high") return "SSS";

	// SSS: external integrations, large scope, or many modules
	if (signals.hasExternalIntegrations) return "SSS";
	if (signals.taskCount >= 8 || signals.modulesAffected >= 4) return "SSS";

	// Medium risk forces SS minimum (internal API, config, database schema)
	if (signals.riskLevel === "medium") return "SS";

	// S-tier: ALL of these must be true — single-file, no new files, known root cause, low risk
	const isS =
		signals.estimatedFilesAffected <= 1 &&
		signals.newFilesCreated === 0 &&
		!signals.requiresInvestigation &&
		!signals.architectureImpact &&
		signals.unknownsSurfaced === 0;

	if (isS) return "S";

	// Default: SS (everything that isn't clearly S or SSS)
	return "SS";
};