const test = require('node:test');
const assert = require('node:assert/strict');

const FlowController = require('../../src/flow/flowController');

function makeLogger() {
  const calls = { debug: [], info: [], warn: [], error: [] };
  return {
    calls,
    debug: (m) => calls.debug.push(m),
    info:  (m) => calls.info.push(m),
    warn:  (m) => calls.warn.push(m),
    error: (m) => calls.error.push(m),
  };
}

function makeHost({
  mode = 'auto',
  allowedActions = new Set(['execsequence', 'execmovement', 'flowmovement', 'emergencystop', 'statuscheck', 'entermaintenance', 'exitmaintenance']),
  allowedSources = true,
  setpointError,
} = {}) {
  const logger = makeLogger();
  const host = {
    logger,
    currentMode: mode,
    unitPolicy: {
      canonical: { flow: 'm3/s' },
      output:    { flow: 'm3/h' },
      convert: (val, from, to, label) => {
        host.calls.convertUnit.push({ val, from, to, label });
        return val * 1000; // pretend m3/h -> m3/s factor
      },
    },
    isValidActionForMode: (action) => allowedActions.has(action),
    isValidSourceForMode: () => allowedSources,
    calls: { executeSequence: [], setpoint: [], calcCtrl: [], convertUnit: [] },
    async executeSequence(seq) { host.calls.executeSequence.push(seq); return { ran: seq }; },
    async setpoint(sp) {
      host.calls.setpoint.push(sp);
      if (setpointError) throw setpointError;
      return { moved: sp };
    },
    calcCtrl: (canonicalFlow) => { host.calls.calcCtrl.push(canonicalFlow); return canonicalFlow / 2; },
  };
  return host;
}

test('handle("parent","execSequence","startup") triggers executeSequence', async () => {
  const host = makeHost();
  const fc = new FlowController({ host });
  const result = await fc.handle('parent', 'execSequence', 'startup');
  assert.deepEqual(host.calls.executeSequence, ['startup']);
  assert.deepEqual(result, { ran: 'startup' });
});

test('handle("parent","execMovement",50) invokes setpoint(50)', async () => {
  const host = makeHost();
  const fc = new FlowController({ host });
  const result = await fc.handle('parent', 'execMovement', 50);
  assert.deepEqual(host.calls.setpoint, [50]);
  assert.deepEqual(result, { moved: 50 });
});

test('handle("parent","flowMovement",X) converts unit -> calcCtrl -> setpoint', async () => {
  const host = makeHost();
  const fc = new FlowController({ host });
  await fc.handle('parent', 'flowMovement', 36);
  assert.equal(host.calls.convertUnit.length, 1);
  assert.equal(host.calls.convertUnit[0].from, 'm3/h');
  assert.equal(host.calls.convertUnit[0].to, 'm3/s');
  assert.deepEqual(host.calls.calcCtrl, [36 * 1000]);
  assert.deepEqual(host.calls.setpoint, [(36 * 1000) / 2]);
});

test('handle("parent","emergencyStop") fires executeSequence("emergencystop") and logs warn', async () => {
  const host = makeHost();
  const fc = new FlowController({ host });
  await fc.handle('parent', 'emergencyStop');
  assert.deepEqual(host.calls.executeSequence, ['emergencystop']);
  assert.ok(host.logger.calls.warn.some((m) => /Emergency stop activated/.test(m)));
});

test('handle rejects non-string action', async () => {
  const host = makeHost();
  const fc = new FlowController({ host });
  await fc.handle('parent', 123, 'x');
  assert.deepEqual(host.calls.executeSequence, []);
  assert.deepEqual(host.calls.setpoint, []);
  assert.ok(host.logger.calls.error.some((m) => /Action must be string/.test(m)));
});

test('handle bails out when action not allowed for mode', async () => {
  const host = makeHost({ allowedActions: new Set(['statuscheck']) });
  const fc = new FlowController({ host });
  await fc.handle('parent', 'execSequence', 'startup');
  assert.deepEqual(host.calls.executeSequence, []);
});

test('handle bails out when source not allowed for mode', async () => {
  const host = makeHost({ allowedSources: false });
  const fc = new FlowController({ host });
  await fc.handle('externalApi', 'execSequence', 'startup');
  assert.deepEqual(host.calls.executeSequence, []);
});

test('handle catches downstream errors and logs them (does not propagate)', async () => {
  const host = makeHost({ setpointError: new Error('boom') });
  const fc = new FlowController({ host });
  const result = await fc.handle('parent', 'execMovement', 12);
  assert.equal(result, undefined);
  assert.ok(host.logger.calls.error.some((m) => /Error handling input/.test(m)));
});

test('handle returns a success envelope for statuscheck', async () => {
  const host = makeHost();
  const fc = new FlowController({ host });
  const out = await fc.handle('parent', 'statusCheck');
  assert.equal(out.status, true);
  assert.ok(out.feedback.includes('statuscheck'));
});

test('handle warns on unimplemented action', async () => {
  const host = makeHost({ allowedActions: new Set(['weirdaction']) });
  const fc = new FlowController({ host });
  await fc.handle('parent', 'weirdAction');
  assert.ok(host.logger.calls.warn.some((m) => /is not implemented/.test(m)));
});

test('constructor validates host', () => {
  assert.throws(() => new FlowController({}), /ctx\.host is required/);
});