import { defineInterceptor } from '../core/interceptors.ts';
import { thenMaybe } from '../core/results.ts';
import type { AnyPadroneBuilder, CommandTypesBase } from '../types/index.ts';

// ── Helpers ─────────────────────────────────────────────────────────────

function formatDuration(ms: number): string {
  if (ms < 1000) return `${ms.toFixed(0)}ms`;
  if (ms < 60_000) return `${(ms / 1000).toFixed(2)}s`;
  const mins = Math.floor(ms / 60_000);
  const secs = ((ms % 60_000) / 1000).toFixed(2);
  return `${mins}m ${secs}s`;
}

// ── Interceptor ─────────────────────────────────────────────────────────

const timingMeta = { id: 'padrone:timing', name: 'padrone:timing', order: -1002 } as const;

function createTimingInterceptor(enabledByDefault: boolean) {
  return defineInterceptor(timingMeta, () => {
    let enabled = enabledByDefault;
    let startTime = 0;

    return {
      parse(_ctx, next) {
        return thenMaybe(next(), (res) => {
          if ('timing' in res.rawArgs) {
            enabled = res.rawArgs.timing !== false;
            delete res.rawArgs.timing;
          }
          if ('time' in res.rawArgs) {
            enabled = res.rawArgs.time !== false;
            delete res.rawArgs.time;
          }
          return res;
        });
      },
      start(_ctx, next) {
        startTime = performance.now();
        return next();
      },
      shutdown(ctx, next) {
        return thenMaybe(next(), (res) => {
          if (enabled) {
            const elapsed = performance.now() - startTime;
            ctx.runtime.error(`\nDone in ${formatDuration(elapsed)}`);
          }
          return res;
        });
      },
    };
  });
}

// ── Extension ───────────────────────────────────────────────────────────

export interface PadroneTimingOptions {
  /** Enable timing by default without requiring `--time` flag. Default: `false`. */
  enabled?: boolean;
}

/**
 * Extension that tracks command execution time.
 *
 * - `--time` / `--timing` → enables timing output
 * - `--no-time` / `--no-timing` → disables timing output
 *
 * Pass `{ enabled: true }` to enable timing by default (can be disabled via `--no-time`).
 *
 * Usage:
 * ```ts
 * // Opt-in via flag
 * createPadrone('my-cli').extend(padroneTiming())
 *
 * // Always on, opt-out via --no-time
 * createPadrone('my-cli').extend(padroneTiming({ enabled: true }))
 * ```
 */
export function padroneTiming(options?: PadroneTimingOptions): <T extends CommandTypesBase>(builder: T) => T {
  return ((builder: AnyPadroneBuilder) => builder.intercept(createTimingInterceptor(options?.enabled ?? false))) as any;
}