import assert from 'node:assert/strict';
import test from 'node:test';
import {
  buildCursorBillingTokenState,
  extractCursorAgentDisplayText,
  normalizeCursorAgentUsage,
  parseCursorAgentUsage,
} from './cursor-agent-usage.mjs';

const SAMPLE_STREAM_JSON = [
  '{"type":"system","subtype":"init","cwd":"/tmp","session_id":"abc","model":"Auto"}',
  '{"type":"user","message":{"role":"user","content":[{"type":"text","text":"reply with exactly: ok"}]}}',
  '{"type":"assistant","message":{"role":"assistant","content":[{"type":"text","text":"ok"}]}}',
  '{"type":"result","subtype":"success","duration_ms":13064,"result":"ok","usage":{"inputTokens":7765,"outputTokens":64,"cacheReadTokens":5427,"cacheWriteTokens":0}}',
].join('\n');

test('parseCursorAgentUsage reads result usage from stream-json stdout', () => {
  const usage = parseCursorAgentUsage(SAMPLE_STREAM_JSON);
  assert.deepEqual(usage, {
    inputTokens: 7765,
    outputTokens: 64,
    cacheReadTokens: 5427,
    cacheWriteTokens: 0,
  });
});

test('normalizeCursorAgentUsage includes cache write tokens in billable input', () => {
  const usage = normalizeCursorAgentUsage({
    inputTokens: 1000,
    outputTokens: 200,
    cacheWriteTokens: 300,
  });
  assert.deepEqual(usage, {
    inputTokens: 1300,
    outputTokens: 200,
    cacheReadTokens: 0,
    cacheWriteTokens: 300,
  });
});

test('extractCursorAgentDisplayText prefers result text', () => {
  assert.equal(extractCursorAgentDisplayText(SAMPLE_STREAM_JSON), 'ok');
});

test('buildCursorBillingTokenState accumulates on prior session billing', () => {
  const tokenState = buildCursorBillingTokenState(
    { inputTokens: 1000, outputTokens: 200 },
    { lastInputTokens: 5000, lastOutputTokens: 800 },
  );
  assert.deepEqual(tokenState, {
    accumulatedInputTokens: 6000,
    accumulatedOutputTokens: 1000,
  });
});