// stats.test.mjs — Unit tests for stats tab computation functions.
//
// Run with: node --test web/test/stats.test.mjs

import { describe, it } from 'node:test';
import assert from 'node:assert/strict';
import { computeTaskStats, computeExecutionStats } from '../app.js';

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

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

function makeExec(state, costUSD = 0, durationMs = null) {
  const started = new Date('2024-01-01T10:00:00Z');
  const finished = durationMs != null
    ? new Date(started.getTime() + durationMs).toISOString()
    : null;
  return {
    id: `exec-${Math.random()}`,
    task_id: 'task-1',
    task_name: 'Test Task',
    state,
    started_at: started.toISOString(),
    finished_at: finished,
    duration_ms: durationMs,
    cost_usd: costUSD,
    exit_code: state === 'completed' ? 0 : 1,
  };
}

// ── computeTaskStats ───────────────────────────────────────────────────────────

describe('computeTaskStats', () => {
  it('groups tasks by state', () => {
    const tasks = [
      makeTask('RUNNING'), makeTask('RUNNING'),
      makeTask('PENDING'),
      makeTask('COMPLETED'), makeTask('COMPLETED'), makeTask('COMPLETED'),
    ];
    const stats = computeTaskStats(tasks);
    assert.equal(stats.byState.RUNNING, 2);
    assert.equal(stats.byState.PENDING, 1);
    assert.equal(stats.byState.COMPLETED, 3);
  });

  it('only includes states that have tasks', () => {
    const tasks = [makeTask('RUNNING')];
    const stats = computeTaskStats(tasks);
    assert.equal(stats.byState.RUNNING, 1);
    assert.equal(stats.byState.PENDING, undefined);
    assert.equal(stats.byState.COMPLETED, undefined);
  });

  it('returns empty byState for empty task list', () => {
    const stats = computeTaskStats([]);
    assert.deepEqual(stats.byState, {});
  });

  it('counts all distinct states correctly', () => {
    const states = ['PENDING', 'QUEUED', 'RUNNING', 'READY', 'COMPLETED',
      'FAILED', 'TIMED_OUT', 'CANCELLED', 'BUDGET_EXCEEDED', 'BLOCKED'];
    const tasks = states.map(makeTask);
    const stats = computeTaskStats(tasks);
    for (const s of states) {
      assert.equal(stats.byState[s], 1, `expected count 1 for state ${s}`);
    }
  });
});

// ── computeExecutionStats ──────────────────────────────────────────────────────

describe('computeExecutionStats', () => {
  it('returns zeros for empty executions', () => {
    const stats = computeExecutionStats([]);
    assert.equal(stats.total, 0);
    assert.equal(stats.successRate, 0);
    assert.equal(stats.totalCostUSD, 0);
    assert.equal(stats.avgDurationMs, null);
    assert.deepEqual(stats.byOutcome, {});
  });

  it('calculates total correctly', () => {
    const execs = [makeExec('completed'), makeExec('failed'), makeExec('cancelled')];
    const stats = computeExecutionStats(execs);
    assert.equal(stats.total, 3);
  });

  it('calculates success rate as fraction of completed out of total', () => {
    const execs = [
      makeExec('completed'), makeExec('completed'), makeExec('completed'),
      makeExec('failed'),
    ];
    const stats = computeExecutionStats(execs);
    assert.equal(stats.successRate, 0.75);
  });

  it('returns success rate 0 when all executions failed', () => {
    const execs = [makeExec('failed'), makeExec('failed')];
    const stats = computeExecutionStats(execs);
    assert.equal(stats.successRate, 0);
  });

  it('returns success rate 1 when all executions completed', () => {
    const execs = [makeExec('completed'), makeExec('completed')];
    const stats = computeExecutionStats(execs);
    assert.equal(stats.successRate, 1);
  });

  it('sums total cost correctly', () => {
    const execs = [makeExec('completed', 0.5), makeExec('completed', 0.25), makeExec('failed', 0.1)];
    const stats = computeExecutionStats(execs);
    assert.ok(Math.abs(stats.totalCostUSD - 0.85) < 0.0001, `expected 0.85, got ${stats.totalCostUSD}`);
  });

  it('calculates average duration from executions with duration_ms', () => {
    const execs = [
      makeExec('completed', 0, 60000),  // 1 min
      makeExec('completed', 0, 120000), // 2 min
      makeExec('failed', 0, 30000),     // 30 sec
    ];
    const stats = computeExecutionStats(execs);
    assert.equal(stats.avgDurationMs, 70000); // (60000+120000+30000)/3
  });

  it('ignores executions without duration_ms in avg calculation', () => {
    const execs = [
      makeExec('completed', 0, 60000),
      makeExec('running', 0, null),     // still running, no duration
    ];
    const stats = computeExecutionStats(execs);
    assert.equal(stats.avgDurationMs, 60000);
  });

  it('returns null avgDurationMs when no executions have duration_ms', () => {
    const execs = [makeExec('running', 0, null)];
    const stats = computeExecutionStats(execs);
    assert.equal(stats.avgDurationMs, null);
  });

  it('groups executions by outcome in byOutcome', () => {
    const execs = [
      makeExec('completed'), makeExec('completed'),
      makeExec('failed'),
      makeExec('cancelled'),
    ];
    const stats = computeExecutionStats(execs);
    assert.equal(stats.byOutcome.completed, 2);
    assert.equal(stats.byOutcome.failed, 1);
    assert.equal(stats.byOutcome.cancelled, 1);
  });
});