'use strict';

const common = require('../common');
const assert = require('assert');

function findInGraph(graph, type, n) {
  let found = 0;
  for (let i = 0; i < graph.length; i++) {
    const node = graph[i];
    if (node.type === type) found++;
    if (found === n) return node;
  }
}

function pruneTickObjects(activities) {
  // Remove one TickObject on each pass until none is left anymore
  // not super efficient, but simplest especially to handle
  // multiple TickObjects in a row
  const tickObject = {
    found: true,
    index: null,
    data: null,
  };

  if (!Array.isArray(activities))
    return activities;

  while (tickObject.found) {
    for (let i = 0; i < activities.length; i++) {
      if (activities[i].type === 'TickObject') {
        tickObject.index = i;
        break;
      } else if (i + 1 >= activities.length) {
        tickObject.found = false;
      }
    }

    if (tickObject.found) {
      // Point all triggerAsyncIds that point to the tickObject
      // to its triggerAsyncId and finally remove it from the activities
      tickObject.data = activities[tickObject.index];
      const triggerId = {
        new: tickObject.data.triggerAsyncId,
        old: tickObject.data.uid,
      };

      activities.forEach(function repointTriggerId(x) {
        if (x.triggerAsyncId === triggerId.old)
          x.triggerAsyncId = triggerId.new;
      });

      activities.splice(tickObject.index, 1);
    }
  }
  return activities;
}

module.exports = common.mustCallAtLeast(function verifyGraph(hooks, graph) {
  pruneTickObjects(hooks);

  // Map actual ids to standin ids defined in the graph
  const idtouid = {};
  const uidtoid = {};
  const typeSeen = {};
  const errors = [];

  const activities = pruneTickObjects(hooks.activities);
  activities.forEach(processActivity);

  function processActivity(x) {
    typeSeen[x.type] ||= 0;
    typeSeen[x.type]++;

    const node = findInGraph(graph, x.type, typeSeen[x.type]);
    if (node == null) return;

    idtouid[node.id] = x.uid;
    uidtoid[x.uid] = node.id;
    if (node.triggerAsyncId == null) return;

    const tid = idtouid[node.triggerAsyncId];
    if (x.triggerAsyncId === tid) return;

    errors.push({
      id: node.id,
      expectedTid: node.triggerAsyncId,
      actualTid: uidtoid[x.triggerAsyncId],
    });
  }

  if (errors.length) {
    errors.forEach((x) =>
      console.error(
        `'${x.id}' expected to be triggered by '${x.expectedTid}', ` +
        `but was triggered by '${x.actualTid}' instead.`,
      ),
    );
  }
  assert.strictEqual(errors.length, 0);

  // Verify that all expected types are present (but more/others are allowed)
  const expTypes = { __proto__: null };
  for (let i = 0; i < graph.length; i++) {
    expTypes[graph[i].type] ??= 0;
    expTypes[graph[i].type]++;
  }

  for (const type in expTypes) {
    assert.ok(typeSeen[type] >= expTypes[type],
              `Type '${type}': expecting: ${expTypes[type]} ` +
              `found: ${typeSeen[type]}`);
  }
}, 0);