/**
 * Pure performance level definitions for leadership evaluations.
 *
 * This module has no Payload imports — it is safe to use from server actions,
 * integration tests, and (later) frontend components. The UI renders these as
 * bar/gradient displays; `score` drives the numeric aggregation and `color`
 * the per-level accent.
 */

export interface PerformanceLevel {
  /** Stable identifier stored on evaluation docs. */
  id: string;
  /** Human-readable label, e.g. shown as "OPERATOR PERFORMANCE LEVEL: EXCELLENT". */
  label: string;
  /** Numeric score (0–100) used for aggregate bar/percentage display. */
  score: number;
  /** Hex color for UI bars/gradients. */
  color: string;
}

/**
 * The performance scale, best to worst. At least five levels are required by the
 * leadership-evaluations feature; six are defined so the top of the scale has room
 * above "EXCELLENT" without collapsing distinctions.
 */
export const PERFORMANCE_LEVELS = [
  { id: "exceptional", label: "EXCEPTIONAL", score: 100, color: "#34d399" },
  { id: "excellent", label: "EXCELLENT", score: 85, color: "#4ade80" },
  { id: "proficient", label: "PROFICIENT", score: 70, color: "#a3e635" },
  { id: "adequate", label: "ADEQUATE", score: 55, color: "#fbbf24" },
  { id: "moderate", label: "MODERATE", score: 40, color: "#94a3b8" },
  { id: "under-review", label: "UNDER REVIEW", score: 25, color: "#f87171" },
] as const satisfies readonly PerformanceLevel[];

export type PerformanceLevelId = (typeof PERFORMANCE_LEVELS)[number]["id"];

const LEVEL_IDS: ReadonlySet<string> = new Set(PERFORMANCE_LEVELS.map((l) => l.id));

/** Type guard for runtime-validated level ids (DB/API input). */
export function isPerformanceLevelId(value: unknown): value is PerformanceLevelId {
  return typeof value === "string" && LEVEL_IDS.has(value);
}

/** Resolve a level definition by id, or null when unknown. */
export function getPerformanceLevel(id: string): PerformanceLevel | null {
  return PERFORMANCE_LEVELS.find((l) => l.id === id) ?? null;
}

export function getLeadershipDisplayLabel(level: Pick<PerformanceLevel, "id" | "label">): string {
  return level.id === "under-review" ? "NEEDS WORK" : level.label;
}