// ── Expansion and the calendar (EVENTS_PLAN.md Phase 4) ────────────────────
//
// The phase's shipped claim: **a published definition with a recurrence produces
// occurrences on its own, and the calendar shows the ones that exist beside the
// ones that will.** The arithmetic underneath is proved separately in
// `eventRecurrence.test.js`; this file is about the two decisions the org lead
// took on 2026-09-02 and the properties they imply:
//
//   • occurrences become REAL ROWS inside a fourteen-day horizon, and beyond it
//     the calendar projects rather than materialising
//   • a projection is never emitted for an instant a run already occupies — so
//     the fortnight inside the horizon is not drawn twice, and a CANCELLED
//     occurrence does not come back as a forecast
//   • expansion looks forward from `now - grace` only, so an occurrence nobody
//     could ever have seen is not invented retroactively
//   • only `ready` definitions expand: publishing IS the schedule switch (§E)
//     and archiving is how an operator turns one off
//   • expansion is idempotent, because it runs every fifteen seconds for ever
//
// Stubbed at the `.db` layer, the shape `eventRunner.test.js` uses.

process.env.DB_HOST = '127.0.0.1'
process.env.DB_PORT = '59999'

const { test, beforeEach, afterEach, after } = require('node:test')
const assert = require('node:assert/strict')

const registries = require('../src/modules/registries')
const runner = require('../src/utils/eventRunner')
const calendarModel = require('../src/model/events/eventCalendar.model')
const definitionsDb = require('../src/model/events/eventDefinitions.db')
const runsDb = require('../src/model/events/eventRuns.db')
const stepsDb = require('../src/model/events/eventRunSteps.db')
const logDb = require('../src/model/events/eventRunLog.db')
// Phase 6: `runsModel.create` prices the version against the switchboard and
// seeds the run's budget, so expansion now reaches two more tables. Unstubbed
// they are a ten-second ECONNREFUSED per occurrence.
const settingsDb = require('../src/model/events/eventActionSettings.db')
const budgetDb = require('../src/model/events/eventRunBudget.db')
const versionsDb = require('../src/model/events/eventVersions.db')
const db = require('../src/utils/db')

after(() => db.close())

// A Tuesday. Chosen so a "friday" schedule has its first occurrence three days
// out — inside the horizon, but not today, which is what keeps "materialised"
// and "due" from being confusable in these fixtures.
const NOW = new Date('2026-09-01T12:00:00Z')

const SPEC = {
  schedule: { kind: 'weekly', days: ['friday'], time: '20:00' },
  phases: [{ key: 'main', label: 'Main', steps: [] }],
}

let store
const originals = {}
for (const [name, mod] of [
  ['definitionsDb', definitionsDb],
  ['runsDb', runsDb],
  ['stepsDb', stepsDb],
  ['logDb', logDb],
  ['versionsDb', versionsDb],
  ['settingsDb', settingsDb],
  ['budgetDb', budgetDb],
]) {
  originals[name] = { mod, fns: { ...mod } }
}

const restoreOriginals = () => {
  for (const { mod, fns } of Object.values(originals)) Object.assign(mod, fns)
}

const clone = (o) => JSON.parse(JSON.stringify(o))

/** One `ready` definition with a published version carrying `spec`. */
function addDefinition(id, overrides = {}) {
  const definition = {
    id,
    title: `Event ${id}`,
    slug: `event-${id}`,
    state: 'ready',
    timezone: 'UTC',
    grace_seconds: 900,
    concurrency_key: null,
    current_version_id: id * 100,
    series_id: null,
    series_name: null,
    series_slug: null,
    spec: clone(SPEC),
    ...overrides,
  }
  store.definitions.set(id, definition)
  store.versions.set(definition.current_version_id, {
    id: definition.current_version_id,
    definition_id: id,
    version: 1,
    spec: definition.spec,
    // Verified by default (Phase 6). §K holds a scheduled occurrence of a version
    // nobody has dry-run, so an unverified fixture would make every test in this
    // file assert nothing about recurrence and everything about that one gate.
    // The gate has its own test below, where an occurrence is what is being
    // measured rather than what is in the way.
    verified_at: new Date('2026-08-01T00:00:00Z'),
    verified_by: 1,
    ...(overrides.version || {}),
  })
  return definition
}

function installStubs() {
  store = { definitions: new Map(), versions: new Map(), runs: [], steps: [], log: [], nextRunId: 1 }

  Object.assign(definitionsDb, {
    findSchedulable: async () =>
      [...store.definitions.values()]
        .filter((d) => d.state === 'ready' && d.current_version_id)
        .map((d) => ({ ...d, version_spec: store.versions.get(d.current_version_id)?.spec || null })),
    getById: async (id) => store.definitions.get(id) || null,
    list: async () => [...store.definitions.values()],
  })

  Object.assign(versionsDb, { getById: async (id) => store.versions.get(id) || null })

  Object.assign(runsDb, {
    materialise: async (run) => {
      const at = new Date(run.scheduled_for).getTime()
      // The unique index, in memory: one row per (definition, scope, instant).
      const clash = store.runs.find(
        (r) => r.definition_id === run.definition_id && r.scope === (run.scope || '') && new Date(r.scheduled_for).getTime() === at,
      )
      if (clash) return null
      const id = store.nextRunId++
      const definition = store.definitions.get(run.definition_id)
      store.runs.push({
        ...run,
        id,
        scope: run.scope || '',
        status: 'scheduled',
        health: 'ok',
        waiting_steps: 0,
        definition_title: definition?.title,
        definition_slug: definition?.slug,
        series_id: definition?.series_id ?? null,
        series_name: definition?.series_name ?? null,
        series_slug: definition?.series_slug ?? null,
        version_number: 1,
      })
      return id
    },
    getById: async (id) => store.runs.find((r) => r.id === id) || null,
    findOccurrence: async (definitionId, scope, at) =>
      store.runs.find(
        (r) => r.definition_id === definitionId && r.scope === (scope || '') && new Date(r.scheduled_for).getTime() === new Date(at).getTime(),
      ) || null,
    listInWindow: async ({ from, to, status = null, scope = null, seriesId = null }) =>
      store.runs
        .filter((r) => {
          const at = new Date(r.scheduled_for).getTime()
          if (at < new Date(from).getTime() || at >= new Date(to).getTime()) return false
          if (status && r.status !== status) return false
          if (scope !== null && scope !== undefined && r.scope !== scope) return false
          if (seriesId && Number(r.series_id) !== Number(seriesId)) return false
          return true
        })
        .sort((a, b) => new Date(a.scheduled_for) - new Date(b.scheduled_for)),
  })

  Object.assign(stepsDb, { materialisePhase: async () => [] })
  Object.assign(logDb, { write: async (line) => { store.log.push(line); return 1 } })

  // Phase 6. No stored switch anywhere in this file: an empty switchboard is a
  // fresh deployment, and expansion is not what this file is measuring.
  Object.assign(settingsDb, { byIds: async () => new Map(), get: async () => null })
  Object.assign(budgetDb, { seed: async () => 0, forRun: async () => [] })
}

beforeEach(() => {
  registries._reset()
  registries.registerCore()
  installStubs()
})

afterEach(restoreOriginals)

const instants = () => store.runs.map((r) => new Date(r.scheduled_for).toISOString()).sort()

// ── Expansion ──────────────────────────────────────────────────────────────

test('a weekly definition materialises exactly the occurrences inside the horizon', async () => {
  addDefinition(1)
  const created = await runner.expandSchedules(NOW)

  // 1 September 2026 is a Tuesday. Fridays inside 14 days: the 4th and the 11th.
  assert.equal(created, 2)
  assert.deepEqual(instants(), ['2026-09-04T20:00:00.000Z', '2026-09-11T20:00:00.000Z'])
})

test('expansion is idempotent — running it again creates nothing', async () => {
  // The property the whole design leans on: this runs every fifteen seconds for
  // ever. `INSERT IGNORE` against the occurrence key is what makes that free,
  // and a second call that created rows would be a duplicate event, not a
  // duplicate row.
  addDefinition(1)
  assert.equal(await runner.expandSchedules(NOW), 2)
  assert.equal(await runner.expandSchedules(NOW), 0)
  assert.equal(await runner.expandSchedules(new Date(NOW.getTime() + 60_000)), 0)
  assert.equal(store.runs.length, 2)
})

test('only `ready` definitions expand — publishing is the switch, archiving turns it off', async () => {
  addDefinition(1, { state: 'draft' })
  addDefinition(2, { state: 'archived' })
  addDefinition(3, { state: 'ready' })
  await runner.expandSchedules(NOW)
  assert.deepEqual([...new Set(store.runs.map((r) => r.definition_id))], [3])
})

test('a draft edit cannot materialise anything — the VERSION spec is what expands', async () => {
  // The definition's working copy says daily; the published version says weekly.
  // A half-typed recurrence an author is midway through must never produce a run.
  const definition = addDefinition(1)
  definition.spec = {
    schedule: { kind: 'weekly', days: ['sunday', 'monday', 'tuesday', 'wednesday', 'thursday', 'friday', 'saturday'], time: '20:00' },
    phases: SPEC.phases,
  }
  await runner.expandSchedules(NOW)
  assert.equal(store.runs.length, 2)
})

test('a manual definition expands to nothing at all', async () => {
  addDefinition(1, { spec: { schedule: { kind: 'manual' }, phases: SPEC.phases } })
  store.versions.get(100).spec = store.definitions.get(1).spec
  assert.equal(await runner.expandSchedules(NOW), 0)
  assert.equal(store.runs.length, 0)
})

test('an occurrence older than the grace window is never materialised at all', async () => {
  // Not materialised-then-swept. A row nobody could ever have seen or cancelled
  // is not history, and writing one would put a `missed` event on the calendar
  // for a date on which this deployment had no such event. The horizon is what
  // makes the missed sweep meaningful instead: a real outage finds rows already
  // there, because they were written a fortnight early.
  addDefinition(1, { grace_seconds: 900 })
  // A Monday, three days after the Friday occurrence — far outside the grace.
  await runner.expandSchedules(new Date('2026-09-07T12:00:00Z'))
  assert.ok(!instants().includes('2026-09-04T20:00:00.000Z'))
})

test('an occurrence still inside the grace window IS materialised', async () => {
  // The case this rule exists for: a definition published four minutes before
  // its own first occurrence. `now - grace` is the window start, so the
  // occurrence that has only just passed is still created and still startable.
  addDefinition(1, { grace_seconds: 3600 })
  await runner.expandSchedules(new Date('2026-09-04T20:10:00Z'))
  assert.ok(instants().includes('2026-09-04T20:00:00.000Z'))
})

test('a DST-adjusted occurrence records WHY its clock reads oddly', async () => {
  // Discovering daylight saving at 3am on the last Sunday in October is the
  // failure this line exists to prevent.
  addDefinition(1, {
    timezone: 'Europe/Berlin',
    spec: { schedule: { kind: 'weekly', days: ['sunday'], time: '02:30' }, phases: SPEC.phases },
  })
  store.versions.get(100).spec = store.definitions.get(1).spec

  await runner.expandSchedules(new Date('2026-03-22T12:00:00Z'))
  const adjusted = store.log.find((l) => l.detail?.dstAdjusted)
  assert.equal(adjusted.detail.dstAdjusted, 'gap')
  assert.equal(adjusted.detail.timezone, 'Europe/Berlin')
  assert.ok(instants().includes('2026-03-29T01:00:00.000Z'))
})

test('a definition whose spec is nonsense is skipped, and the sweep carries on', async () => {
  // A spec written straight into the database with a shape the validator would
  // have refused is a bad row, not a bad tick.
  addDefinition(1, { spec: { schedule: { kind: 'weekly', days: ['froday'], time: '20:00' }, phases: SPEC.phases } })
  store.versions.get(100).spec = store.definitions.get(1).spec
  addDefinition(2)

  const created = await runner.expandSchedules(NOW)
  assert.equal(created, 2)
  assert.deepEqual([...new Set(store.runs.map((r) => r.definition_id))], [2])
})

test('every materialised occurrence is marked as coming from the schedule', async () => {
  // `started_by` is NULL for a scheduled occurrence and for one an admin started
  // whose account has since gone, so the log is the only place the two are told
  // apart.
  addDefinition(1)
  await runner.expandSchedules(NOW)
  const created = store.log.filter((l) => l.kind === 'run.created' && l.detail?.source)
  assert.equal(created.length, 2)
  for (const line of created) {
    assert.equal(line.detail.source, 'schedule')
    assert.equal(line.detail.by, null)
  }
})

// ── The calendar ───────────────────────────────────────────────────────────

test('inside the horizon the calendar shows runs; beyond it, projections', async () => {
  addDefinition(1)
  await runner.expandSchedules(NOW)

  const result = await calendarModel.calendar({
    from: new Date('2026-09-01T00:00:00Z'),
    to: new Date('2026-10-01T00:00:00Z'),
    now: NOW,
  })

  const kinds = result.entries.map((e) => `${e.kind} ${new Date(e.scheduledFor).toISOString().slice(0, 10)}`)
  assert.deepEqual(kinds, [
    'run 2026-09-04',
    'run 2026-09-11',
    'projected 2026-09-18',
    'projected 2026-09-25',
  ])
  // The forecast is arithmetic and says so: no row, nothing to open.
  for (const entry of result.entries.filter((e) => e.kind === 'projected')) {
    assert.equal(entry.runId, null)
    assert.equal(entry.status, null)
  }
})

test('a projection is never drawn over an instant a run already occupies', async () => {
  addDefinition(1)
  await runner.expandSchedules(NOW)
  const result = await calendarModel.calendar({
    from: new Date('2026-09-01T00:00:00Z'),
    to: new Date('2026-09-15T00:00:00Z'),
    now: NOW,
  })
  assert.equal(result.entries.length, 2)
  assert.ok(result.entries.every((e) => e.kind === 'run'))
})

test('a CANCELLED occurrence does not come back as a forecast', async () => {
  // The same rule, and the case it earns its keep on. An operator who called an
  // event off must not find it on the calendar again ten seconds later looking
  // like it is still coming.
  addDefinition(1)
  await runner.expandSchedules(NOW)
  store.runs[0].status = 'cancelled'

  const result = await calendarModel.calendar({
    from: new Date('2026-09-01T00:00:00Z'),
    to: new Date('2026-09-15T00:00:00Z'),
    now: NOW,
  })
  const onTheDay = result.entries.filter((e) => new Date(e.scheduledFor).toISOString().startsWith('2026-09-04'))
  assert.equal(onTheDay.length, 1)
  assert.equal(onTheDay[0].kind, 'run')
  assert.equal(onTheDay[0].status, 'cancelled')
})

test('a status filter suppresses projections, because a forecast has no status', async () => {
  addDefinition(1)
  await runner.expandSchedules(NOW)
  const result = await calendarModel.calendar({
    from: new Date('2026-09-01T00:00:00Z'),
    to: new Date('2026-10-01T00:00:00Z'),
    status: 'scheduled',
    now: NOW,
  })
  assert.ok(result.entries.every((e) => e.kind === 'run'))
  assert.equal(result.entries.length, 2)
})

test('a series filter narrows runs and projections alike', async () => {
  addDefinition(1, { series_id: 7, series_name: 'Royal Spy Mission' })
  addDefinition(2, { series_id: 9, series_name: 'Something Else' })
  await runner.expandSchedules(NOW)

  const result = await calendarModel.calendar({
    from: new Date('2026-09-01T00:00:00Z'),
    to: new Date('2026-10-01T00:00:00Z'),
    seriesId: 7,
    now: NOW,
  })
  assert.ok(result.entries.length > 2)
  assert.ok(result.entries.every((e) => e.seriesName === 'Royal Spy Mission'))
  assert.ok(result.entries.some((e) => e.kind === 'projected'))
})

test('the window is bounded, inverted windows are refused, and the horizon is reported', async () => {
  const wide = await calendarModel.calendar({
    from: new Date('2026-01-01T00:00:00Z'),
    to: new Date('2027-01-01T00:00:00Z'),
    now: NOW,
  })
  assert.equal(wide.ok, false)
  assert.equal(wide.status, 400)
  assert.match(wide.errors.join(' '), /at most 92 days/)

  const inverted = await calendarModel.calendar({
    from: new Date('2026-09-10T00:00:00Z'),
    to: new Date('2026-09-01T00:00:00Z'),
    now: NOW,
  })
  assert.equal(inverted.ok, false)

  const fine = await calendarModel.calendar({
    from: new Date('2026-09-01T00:00:00Z'),
    to: new Date('2026-09-15T00:00:00Z'),
    horizonDays: 14,
    now: NOW,
  })
  assert.equal(fine.ok, true)
  assert.equal(fine.horizon.toISOString(), '2026-09-15T12:00:00.000Z')
})