// ── Event definitions — the save path ──────────────────────────────────────
//
// EVENTS.md §D and "Versioning, and editing a live event". A definition is
// operator-authored data, and this file is the boundary that decides whether a
// version of it may exist. The authoring UI (Phase 3, then Phase 13) will
// re-check some of this for the sake of a good inline error; that second copy is
// expected to drift, so this one is the one that decides, and a definition
// arriving by any other route gets the same answer.
//
// **The three rules with teeth, and each is a rule about time rather than about
// shape:**
//
// 1. Publishing SNAPSHOTS. It copies the working spec into an immutable
//    `event_versions` row and points `current_version_id` at it. Editing
//    afterwards is free and does not touch the row a live run pinned.
// 2. A dormant step blocks a PUBLISH and never a SAVE. An uninstalled module
//    must not make an author's work uneditable, and it must not let a version be
//    published that names a verb nobody can perform.
// 3. Archiving is what "delete" means here. `event_runs.version_id` RESTRICTs, so
//    a hard delete of a definition that has ever run is refused by the database
//    anyway — and the row's history is the thing an audit reads.

const db = require('./eventDefinitions.db')
const versionsDb = require('./eventVersions.db')
const runsDb = require('./eventRuns.db')
const logDb = require('./eventRunLog.db')
const seriesDb = require('./eventSeries.db')
const spec = require('../../events/spec')
const authorize = require('../../events/authorize')
const verifier = require('../../events/verify')
const registries = require('../../modules/registries')
const { slugify, uniqueSlug } = require('../teams/teamSlug')
const { cleanBody } = require('../../utils/sanitizeHtml')

const MAX_TITLE = 200
const MAX_SUMMARY = 500
const MAX_URL = 500
const MAX_CONCURRENCY_KEY = 190

// A day either side of §D's default. Below a minute the grace window cannot
// survive a single slow boot; above a day a "missed" occurrence would start
// silently the following afternoon, which is the exact behaviour §E forbids.
const MIN_GRACE_SECONDS = 60
const MAX_GRACE_SECONDS = 86_400

/**
 * IANA zone names, checked against the platform's own database rather than a
 * list. `Intl.DateTimeFormat` throws `RangeError` on an unknown zone, and Node
 * ships the full tzdata — so this is the same check Phase 4's occurrence
 * arithmetic will make, asked one screen earlier where an operator can fix it.
 */
function isTimezone(tz) {
  try {
    Intl.DateTimeFormat(undefined, { timeZone: tz })
    return true
  } catch {
    return false
  }
}

const isPlainObject = (v) => v !== null && typeof v === 'object' && !Array.isArray(v)

const trimOrNull = (v, max) => {
  if (v === undefined || v === null) return null
  const s = String(v).trim()
  return s === '' ? null : s.slice(0, max)
}

/**
 * Validate an incoming definition against the registries and the schema.
 *
 * `{ ok: true, definition }` with a normalised row ready for insert/update, or
 * `{ ok: false, errors }` listing every problem rather than the first.
 *
 * `existing` is the row being edited, or null on a create. It is what lets a
 * dormant step survive: the ids already in the saved spec widen what the spec
 * validator will accept, so an uninstall is never destructive after the fact.
 */
async function validate(input, { existing = null } = {}) {
  const errors = []
  const body = isPlainObject(input) ? input : {}

  const title = trimOrNull(body.title, MAX_TITLE)
  if (!title) errors.push('title is required')

  const summary = trimOrNull(body.summary, MAX_SUMMARY)
  const imageUrl = trimOrNull(body.imageUrl, MAX_URL)
  const concurrencyKey = trimOrNull(body.concurrencyKey, MAX_CONCURRENCY_KEY)

  // The storyline. Sanitized on write, exactly as a wiki page and a forum post
  // are: it is author-supplied HTML that ends up on a public page.
  const storyline = body.body === undefined || body.body === null ? null : cleanBody(String(body.body))

  const timezone = trimOrNull(body.timezone, 64) || existing?.timezone || 'UTC'
  if (!isTimezone(timezone)) errors.push(`timezone: "${timezone}" is not an IANA zone name`)

  const graceRaw = body.graceSeconds === undefined ? (existing?.grace_seconds ?? 900) : body.graceSeconds
  const graceSeconds = Number(graceRaw)
  if (
    !Number.isInteger(graceSeconds) ||
    graceSeconds < MIN_GRACE_SECONDS ||
    graceSeconds > MAX_GRACE_SECONDS
  ) {
    errors.push(`graceSeconds must be an integer ${MIN_GRACE_SECONDS}..${MAX_GRACE_SECONDS}`)
  }

  let seriesId = null
  if (body.seriesId !== undefined && body.seriesId !== null && body.seriesId !== '') {
    seriesId = Number(body.seriesId)
    if (!Number.isInteger(seriesId) || seriesId < 1) {
      errors.push('seriesId must be an integer')
      seriesId = null
    } else if (!(await seriesDb.exists(seriesId))) {
      // Checked here as well as by the foreign key, because a 1452 reaching a
      // controller is a 500 and this is a 400 an author can act on.
      errors.push(`seriesId ${seriesId} does not exist`)
      seriesId = null
    }
  } else if (existing) {
    seriesId = existing.series_id
  }

  const seriesOrderRaw = body.seriesOrder === undefined ? (existing?.series_order ?? 0) : body.seriesOrder
  const seriesOrder = Number(seriesOrderRaw)
  if (!Number.isInteger(seriesOrder)) errors.push('seriesOrder must be an integer')

  // Whether this event is announced on the public calendar (Phase 14a). It is
  // NOT whether it may run: `state` answers that, and the two are separate
  // precisely because publishing is what makes a definition runnable — an
  // unlisted event still schedules, still runs and is still on the admin
  // calendar. A missing key means "leave it as it was", and a NEW definition
  // defaults to listed, which is the column's own default and the ordinary
  // case; unlisting is the deliberate act.
  const listed = body.listed === undefined ? (existing ? Boolean(existing.listed) : true) : Boolean(body.listed)

  // ── the spec ──
  const rawSpec = body.spec === undefined ? existing?.spec ?? spec.emptySpec() : body.spec
  const known = existing?.spec ? spec.actionIdsIn(existing.spec) : []
  const checked = spec.validate(rawSpec, { knownActionIds: known })
  if (!checked.ok) errors.push(...checked.errors)

  // ── the slug ──
  //
  // Derived from the title on create and FROZEN afterwards, like a Team's: the
  // public event page lives at it, and a retitle must not break a link somebody
  // posted in Discord. An author who genuinely needs a different address makes a
  // new definition.
  let slug = existing?.slug || null
  if (!slug) {
    const stem = slugify(title || '') || 'event'
    const taken = (await db.list()).map((d) => d.slug)
    slug = uniqueSlug(stem, taken, { fallback: 'event' })
  }

  if (errors.length) return { ok: false, errors }

  return {
    ok: true,
    definition: {
      title,
      slug,
      summary,
      body: storyline,
      image_url: imageUrl,
      owner_module: existing?.owner_module ?? null,
      series_id: seriesId,
      series_order: seriesOrder,
      concurrency_key: concurrencyKey,
      grace_seconds: graceSeconds,
      timezone,
      listed,
      spec: checked.spec,
    },
  }
}

/** Create a draft. */
async function create(input, userId, { role = null } = {}) {
  const result = await validate(input)
  if (!result.ok) return result
  const floor = checkRoleFloor(result.definition.spec, role)
  if (floor) return floor
  const id = await db.insert({ ...result.definition, created_by: userId })
  return { ok: true, id, definition: await db.getById(id) }
}

/**
 * Edit a definition.
 *
 * An `archived` definition is not editable. That is the one state check here,
 * and it is a real one rather than a formality: archiving is how a definition is
 * retired, and a retired definition that can still be edited is a definition
 * somebody will edit and then wonder why it never runs.
 */
async function save(id, input, userId, { role = null } = {}) {
  const existing = await db.getById(id)
  if (!existing) return { ok: false, status: 404, errors: ['no such event definition'] }
  if (existing.state === 'archived') {
    return { ok: false, status: 409, errors: ['an archived definition cannot be edited'] }
  }
  const result = await validate(input, { existing })
  if (!result.ok) return result
  const floor = checkRoleFloor(result.definition.spec, role)
  if (floor) return floor
  await db.update(id, { ...result.definition, updated_by: userId })
  return { ok: true, id, definition: await db.getById(id) }
}

/**
 * Publish: snapshot the working spec into an immutable version and go `ready`.
 *
 * The spec is re-validated here against the registries as they stand RIGHT NOW,
 * not trusted from the save that wrote it. A module uninstalled between the two
 * is the whole reason: the save was legitimate, and publishing a version whose
 * steps name a verb nobody can perform would be a run that fails at dispatch
 * with the world half-changed.
 */
async function publish(id, userId) {
  const existing = await db.getById(id)
  if (!existing) return { ok: false, status: 404, errors: ['no such event definition'] }
  if (existing.state === 'archived') {
    return { ok: false, status: 409, errors: ['an archived definition cannot be published'] }
  }

  const checked = spec.validate(existing.spec, {
    knownActionIds: spec.actionIdsIn(existing.spec),
  })
  if (!checked.ok) return { ok: false, status: 400, errors: checked.errors }

  const publishable = spec.publishable(checked.spec)
  if (!publishable.ok) {
    return {
      ok: false,
      status: 409,
      errors: [
        `cannot publish: no module registers ${publishable.dormant.join(', ')}`,
      ],
    }
  }
  if (!checked.spec.phases.some((p) => p.steps.length)) {
    // An empty event publishes cleanly and then does nothing, which looks like a
    // broken run rather than an empty one. Refusing costs an author one click and
    // saves an operator a diagnosis.
    return { ok: false, status: 400, errors: ['cannot publish: no phase has any steps'] }
  }

  const version = await versionsDb.nextVersion(id)
  const versionId = await versionsDb.insert(id, version, checked.spec, userId)
  await db.markReady(id, versionId, userId)

  // Occurrences already materialised ahead of their instant move to the new
  // version; ones that have begun do not (org lead, 2026-09-02). Logged per run
  // rather than only counted, because "which version did this run actually use"
  // is the first question an audit asks and the pin is no longer immutable while
  // a run is still `scheduled`.
  const pending = await runsDb.listScheduledFor(id)
  const stale = pending.filter((r) => Number(r.version_id) !== Number(versionId))
  const repinned = stale.length ? await runsDb.repinScheduled(id, versionId) : 0
  for (const run of stale) {
    await logDb.write({
      runId: run.id,
      kind: 'run.status',
      detail: {
        to: 'scheduled',
        repinned: true,
        fromVersionId: run.version_id,
        toVersionId: versionId,
        toVersion: version,
        by: userId,
      },
    })
  }

  return { ok: true, versionId, version, repinned, definition: await db.getById(id) }
}

/**
 * Archive.
 *
 * Refused while a run of this definition is still in flight — not because the
 * database would object (it would not; archiving is an UPDATE), but because the
 * screen the run is on reads its title and state from here, and retiring a
 * definition mid-run makes the console describe something that is no longer
 * supposed to exist. Cancel the run, then archive.
 */
async function archive(id, userId) {
  const existing = await db.getById(id)
  if (!existing) return { ok: false, status: 404, errors: ['no such event definition'] }
  if (existing.state === 'archived') return { ok: true, definition: existing }

  const active = await runsDb.countActiveForDefinition(id)
  if (active > 0) {
    return {
      ok: false,
      status: 409,
      errors: [`cannot archive: ${active} run(s) of this definition are still in flight`],
    }
  }
  await db.archive(id, userId)
  return { ok: true, definition: await db.getById(id) }
}

/**
 * The role floor on a spec's steps (§K, Phase 6).
 *
 * §K's table reads "any step whose action is above `notify` — `admin` only", and
 * the line falls between `inspect` and `change` for the reason the default-off
 * rule does (org lead, 2026-09-03): an `inspect` action reads state and writes
 * nothing, and an editor who cannot author a step that WAITS has an authoring
 * role that cannot author.
 *
 * Checked at SAVE rather than only at publish, which is the difference between
 * telling an editor now and telling them after they have written twelve steps.
 * Publish re-checks anyway — it re-checks everything, against the registries as
 * they stand at that moment — because an action's risk class is a module's
 * declaration and a module can be upgraded between the two.
 */
function worldChangingSteps(specValue) {
  const out = []
  for (const phase of specValue?.phases || []) {
    for (const step of phase.steps || []) {
      const action = registries.eventAction(step.actionId)
      if (action && authorize.changesWorld(action)) out.push(action)
    }
  }
  return out
}

function checkRoleFloor(specValue, role) {
  if (!role || role === 'admin') return null
  const blocked = worldChangingSteps(specValue)
  if (!blocked.length) return null
  const names = [...new Set(blocked.map((a) => `"${a.label}"`))]
  // Agreement, because this sentence is read by the person it refuses. The list
  // is almost always one long -- an editor adds one world-changing step and is
  // stopped -- so `"Spawn creatures" change the world` is the case that shows,
  // and it reads as a bug in the sentence rather than a rule about the step.
  const one = names.length === 1
  return {
    ok: false,
    status: 403,
    errors: [
      `${names.join(', ')} ${one ? 'changes' : 'change'} the world, so only an administrator may author a step that uses ${one ? 'it' : 'them'}`,
    ],
  }
}

/**
 * Dry-run a definition, and record the pass when there is a version to record it
 * on (Phase 6).
 *
 * The target follows the definition's state: a `ready` definition is verified
 * against the version that would actually run, a draft against the working spec
 * the author is still holding. See `events/verify.js` for why that is one act at
 * two moments rather than two rules.
 */
async function verify(id, user) {
  const existing = await db.getById(id)
  if (!existing) return { ok: false, status: 404, errors: ['no such event definition'] }
  if (existing.state === 'archived') {
    return { ok: false, status: 409, errors: ['an archived definition cannot be verified'] }
  }

  const version =
    existing.state === 'ready' && existing.current_version_id
      ? await versionsDb.getById(existing.current_version_id)
      : null
  const target = version?.spec || existing.spec
  if (!target?.phases?.length) {
    return { ok: false, status: 409, errors: ['this definition has no phases to verify'] }
  }

  const report = await verifier.verifySpec(target, { user })

  if (version && report.ok) {
    await versionsDb.markVerified(version.id, user?.id || null)
    // Written to every run already pinned to this version, because that is where
    // an operator asks the question: a scheduled occurrence that was being held
    // is now going to start, and the line saying why belongs on it.
    for (const run of await runsDb.listScheduledFor(id)) {
      if (Number(run.version_id) !== Number(version.id)) continue
      await logDb.write({
        runId: run.id,
        kind: 'version.verified',
        detail: { versionId: version.id, version: version.version, by: user?.id || null },
      })
    }
  }

  return {
    ok: true,
    report,
    // Which spec was verified, said plainly, because the two answer different
    // questions and a report that did not say would be read as the other one.
    target: version ? 'version' : 'draft',
    versionId: version?.id || null,
    version: version?.version || null,
    recorded: Boolean(version && report.ok),
  }
}

module.exports = {
  validate,
  create,
  save,
  publish,
  archive,
  verify,
  checkRoleFloor,
  isTimezone,
  MIN_GRACE_SECONDS,
  MAX_GRACE_SECONDS,
}