// Run: node --test frontend/src/shared/appWebviewBudget.test.ts
import { test } from 'node:test';
import assert from 'node:assert/strict';
import {
  requestAppSlot,
  releaseAppSlot,
  MAX_LIVE_APP_WEBVIEWS as MAX,
} from './appWebviewBudget.ts';

// The module holds shared state, so every test fills, asserts, then releases its own keys to leave a clean slate.
function fill(prefix: string, n: number, basePriority: number): string[] {
  const keys: string[] = [];
  for (let i = 0; i < n; i++) {
    const k = `${prefix}${i}`;
    assert.equal(requestAppSlot(k, basePriority + i, false), true, `slot ${i} should be granted below cap`);
    keys.push(k);
  }
  return keys;
}
function release(keys: string[]): void {
  for (const k of keys) releaseAppSlot(k);
}

test('grants every request below the cap', () => {
  const keys = fill('a', MAX, 10);
  release(keys);
});

test('denies a farther card once the cap is full', () => {
  const keys = fill('b', MAX, 10);
  assert.equal(requestAppSlot('b-far', 9999, false), false, 'a card farther than all live cards is denied');
  release([...keys, 'b-far']);
});

test('a closer card evicts the farthest, and the evicted one is then denied', () => {
  const keys = fill('c', MAX, 100); // priorities 100..100+MAX-1; farthest is the last
  assert.equal(requestAppSlot('c-near', 1, false), true, 'a closer card takes a slot by eviction');
  // The farthest original (highest priority) was evicted; re-requesting it now fails (still full, still farthest).
  const evicted = `c${MAX - 1}`;
  assert.equal(requestAppSlot(evicted, 100 + MAX - 1, false), false, 'the evicted farthest card cannot re-enter');
  release([...keys, 'c-near']);
});

test('pinned cards bypass the cap and are never evicted', () => {
  const keys = fill('d', MAX, 10);
  assert.equal(requestAppSlot('d-pin', 0, true), true, 'pinned card is admitted past a full cap');
  // A pinned card does not consume an evictable slot, so an unpinned farther card is still denied.
  assert.equal(requestAppSlot('d-far', 9999, false), false, 'unpinned farther card still denied with a pin present');
  // Another pin also admitted.
  assert.equal(requestAppSlot('d-pin2', 0, true), true, 'second pinned card also admitted');
  release([...keys, 'd-pin', 'd-pin2', 'd-far']);
});

test('releasing a slot lets a previously-denied card in', () => {
  const keys = fill('e', MAX, 10);
  assert.equal(requestAppSlot('e-wait', 9999, false), false, 'denied while full');
  releaseAppSlot(keys[0]);
  assert.equal(requestAppSlot('e-wait', 9999, false), true, 'admitted after a slot frees');
  release([keys[1], keys[2], keys[3], keys[4], keys[5], 'e-wait'].filter(Boolean));
});

test('re-requesting an already-live card just updates it, no extra slot', () => {
  const keys = fill('f', MAX, 10);
  assert.equal(requestAppSlot(keys[0], 5, false), true, 'existing card re-request is idempotent');
  assert.equal(requestAppSlot('f-far', 9999, false), false, 'still full after a re-request');
  release([...keys, 'f-far']);
});