/**
 * Shared pure utility functions used across screener, portfolio, and safe-buys pages.
 * All functions are stateless and framework-agnostic.
 */

// ── Signal ordering ───────────────────────────────────────────────────────────

export type Signal =
  | '✅ Strong Buy'
  | '⚡ Momentum'
  | '🔄 Neutral'
  | '⚠️  Speculation'
  | '❌ Avoid';

const SIGNAL_ORDER: Record<string, number> = {
  '✅ Strong Buy':   0,
  '⚡ Momentum':     1,
  '🔄 Neutral':      2,
  '⚠️  Speculation': 3,
  '❌ Avoid':        4,
};

/** Returns sort order for a signal string (lower = stronger). Unknown signals → 5. */
export function sigOrd(signal: string | null | undefined): number {
  return SIGNAL_ORDER[signal ?? ''] ?? 5;
}

/** Sorts an array of screener result rows by signal strength (strongest first). */
export function sorted<T extends { signal?: string | null }>(arr: T[]): T[] {
  return [...(arr ?? [])].sort((a, b) => sigOrd(a.signal) - sigOrd(b.signal));
}

// ── Verdict label helpers ─────────────────────────────────────────────────────

/**
 * Converts a long verdict label into a short display string.
 * e.g. "🟢 BUY (High Conviction)" → "Strong"
 */
export function verdictShort(label: string | null | undefined): string {
  if (!label) return '—';
  if (label.includes('High Conviction')) return 'Strong';
  if (label.includes('Speculative'))     return 'Speculative';
  if (label.includes('BUY'))             return 'Buy';
  if (label.includes('Efficient'))       return 'Efficient';
  if (label.includes('Attractive'))      return 'Attractive';
  if (label.includes('Neutral'))         return 'Hold';
  if (label.includes('REJECT'))          return 'Reject';
  if (label.includes('Avoid'))           return 'Avoid';
  return label.replace(/[🟢🟡🔴]/u, '').trim();
}

/**
 * Returns a CSS colour class ('green' | 'yellow' | 'red') based on
 * the emoji prefix of a verdict label.
 */
export function vClass(label: string | null | undefined): 'green' | 'yellow' | 'red' {
  if (label?.startsWith('🟢')) return 'green';
  if (label?.startsWith('🟡')) return 'yellow';
  return 'red';
}

// ── Number formatters ─────────────────────────────────────────────────────────

/** Formats a P/E ratio — e.g. 22.5 → "22.5x", null → "—" */
export function fmtPE(v: number | null | undefined): string {
  return v != null ? v + 'x' : '—';
}

/** Full currency format — e.g. 1234.5 → "$1,234.50" */
export function fmt(n: number | null | undefined): string {
  return n != null
    ? new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' }).format(n)
    : '—';
}

/** Compact currency format (no cents) — e.g. 1234.5 → "$1,235" */
export function fmtShort(n: number | null | undefined): string {
  return n != null
    ? new Intl.NumberFormat('en-US', {
        style: 'currency',
        currency: 'USD',
        maximumFractionDigits: 0,
      }).format(n)
    : '—';
}

/**
 * Returns 'green' for non-negative G/L percentage, 'red' otherwise.
 * Accepts string (e.g. "12.5") or number.
 */
export function glClass(pct: string | number | null | undefined): 'green' | 'red' {
  return parseFloat(String(pct ?? 0)) >= 0 ? 'green' : 'red';
}

/**
 * Returns a CSS colour class for a portfolio advice string based on its emoji prefix.
 * 🟢 → 'green', 🟡 → 'yellow', 🟠 → 'orange', 🔴 → 'red', else 'gray'.
 */
export function advClass(advice: string | null | undefined): 'green' | 'yellow' | 'orange' | 'red' | 'gray' {
  if (advice?.includes('🟢')) return 'green';
  if (advice?.includes('🟡')) return 'yellow';
  if (advice?.includes('🟠')) return 'orange';
  if (advice?.includes('🔴')) return 'red';
  return 'gray';
}