// filter.test.mjs — TDD contract tests for filterTasks
//
// filterTasks is defined inline here to establish the expected behaviour.
// Once filterTasks is added to web/app.js (or a shared module), remove the
// inline definition and import it instead.
//
// Run with: node --test web/test/filter.test.mjs

import { describe, it } from 'node:test';
import assert from 'node:assert/strict';

// ── Implementation under contract ─────────────────────────────────────────────
// Remove this block once filterTasks is exported from app.js / a shared module.

const HIDE_STATES = new Set(['COMPLETED', 'FAILED']);

function filterTasks(tasks, hideCompletedFailed = false) {
  if (!hideCompletedFailed) return tasks;
  return tasks.filter(t => !HIDE_STATES.has(t.state));
}

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

function makeTask(state) {
  return { id: state, name: `task-${state}`, state };
}

// ── Tests ──────────────────────────────────────────────────────────────────────

describe('filterTasks', () => {
  it('removes COMPLETED tasks when hideCompletedFailed=true', () => {
    const tasks = [makeTask('COMPLETED'), makeTask('PENDING')];
    const result = filterTasks(tasks, true);
    assert.ok(!result.some(t => t.state === 'COMPLETED'), 'COMPLETED should be excluded');
    assert.equal(result.length, 1);
  });

  it('removes FAILED tasks when hideCompletedFailed=true', () => {
    const tasks = [makeTask('FAILED'), makeTask('RUNNING')];
    const result = filterTasks(tasks, true);
    assert.ok(!result.some(t => t.state === 'FAILED'), 'FAILED should be excluded');
    assert.equal(result.length, 1);
  });

  it('returns all tasks when hideCompletedFailed=false', () => {
    const tasks = [
      makeTask('COMPLETED'),
      makeTask('FAILED'),
      makeTask('PENDING'),
      makeTask('RUNNING'),
    ];
    const result = filterTasks(tasks, false);
    assert.equal(result.length, 4, 'all tasks should be returned');
    assert.deepEqual(result, tasks);
  });

  it('returns all tasks when hideCompletedFailed is omitted (default false)', () => {
    const tasks = [makeTask('COMPLETED'), makeTask('FAILED'), makeTask('QUEUED')];
    const result = filterTasks(tasks);
    assert.equal(result.length, 3);
  });

  it('includes PENDING, QUEUED, RUNNING, TIMED_OUT, CANCELLED, BUDGET_EXCEEDED when hiding', () => {
    const activeStates = ['PENDING', 'QUEUED', 'RUNNING', 'TIMED_OUT', 'CANCELLED', 'BUDGET_EXCEEDED'];
    const tasks = activeStates.map(makeTask);
    const result = filterTasks(tasks, true);
    assert.equal(result.length, activeStates.length, 'all non-terminal active states should be kept');
    for (const state of activeStates) {
      assert.ok(result.some(t => t.state === state), `${state} should be included`);
    }
  });

  it('returns an empty array when given an empty array', () => {
    assert.deepEqual(filterTasks([], true), []);
    assert.deepEqual(filterTasks([], false), []);
  });
});