// ── What the three Events screens say, and what they let staff press ───────
//
// EVENTS.md §I. None of this is a boundary. `events/spec.js` on the server
// decides what may be saved, and the six control statements decide what may
// happen to a run — every one of them is a compare-and-set that re-checks the
// status this file only *predicted*. What is here is the part that would be
// wrong silently: a form that drops an authored step, a params box that posts a
// string where the action declared an int, and above all a console that offers a
// button the server is going to refuse.
//
// **The controls are modelled here rather than inline in the console for one
// reason: they can be tested against the server's rules.** A button that 409s is
// not a bug the way a wrong write is, but it is the failure mode an operator
// meets at 2am while the thing they are trying to stop keeps running — so the
// guards are written twice on purpose and the copy is checked.

// **The condition builder is borrowed, not rebuilt.** §I says the step editor
// reuses "the condition builder, exactly" — and a phase's advance gate is
// literally the engagement grammar, validated on the server by
// `engagement/conditions.js`. Importing the row helpers is what keeps this screen
// from becoming a second opinion about a grammar core owns.
import { conditionRowsFrom, conditionsFromRows, coerceLiteral } from './engagementRules.js'

// A run that is over. Verbatim `eventRuns.db`'s TERMINAL.
export const TERMINAL_RUN_STATUSES = ['completed', 'cancelled', 'failed', 'missed']

export const isTerminalRun = (status) => TERMINAL_RUN_STATUSES.includes(status)

/** A step waiting on a human: `running`, with nothing holding it. */
export const isParked = (step) => Boolean(step && step.status === 'running' && step.parked)

/**
 * The highest `seq` of a step in this phase that is not still `pending` — the
 * furthest the phase has got — or null when none of it has been attempted.
 *
 * The same rule as the server's `lastStartedSeq`, over the step list the console
 * already has, and used only to decide whether to OFFER retry. The near miss is
 * worth keeping in view: "the lowest step that is not finished" looks like the
 * same thing and is not, because the runner steps OVER a failed step. Under that
 * rule a phase that carried on past an `on_failure: skip` failure and then paused
 * at a later one would offer retry on the wrong step.
 */
export function lastStartedSeqOf(steps, phase) {
  const started = (steps || [])
    .filter((s) => s.phase === phase && s.status !== 'pending')
    .map((s) => Number(s.seq))
  return started.length ? Math.max(...started) : null
}

/**
 * Which run-level controls to offer.
 *
 * `pause` is `starting`/`running` only: a `scheduled` occurrence that should not
 * happen is cancelled, not paused. `cancel` is everything non-terminal — "this
 * is not happening" is a decision made before a run starts as often as during
 * one.
 *
 * **`advance` is offered only when the phase is genuinely waiting on its gate**,
 * which is the same test the server makes and is stated here in the same words
 * on purpose: this decides what is *offered*, the server decides what is
 * *allowed*, and a button that is present and always refused is the "control
 * that answers 409 and does nothing" this feature has refused twice. The gate
 * must be open-and-unsatisfied AND no step of the phase may still be pending or
 * running — a phase held by a step is held by the step, and skip is its control.
 */
export function runControlsFor(run, gates = [], steps = []) {
  if (!run) return { pause: false, resume: false, cancel: false, advance: false }
  const terminal = isTerminalRun(run.status)
  const gate = (gates || []).find((g) => g.phase === run.currentPhase)
  const stepOpen = (steps || []).some(
    (s) => s.phase === run.currentPhase && ['pending', 'running'].includes(s.status),
  )
  return {
    pause: ['starting', 'running'].includes(run.status),
    resume: run.status === 'paused',
    cancel: !terminal,
    advance: run.status === 'running' && Boolean(gate) && !gate.satisfied && !stepOpen,
  }
}

/**
 * Which step-level controls to offer, for one step of one run.
 *
 * `retry` carries the guard worth restating: only while the run is PAUSED, only
 * on a `failed` step of the phase the run is currently in, and only when that
 * step is the furthest one the phase has reached. A failed step under an
 * `on_failure` of `skip` is one the run has already moved past, and re-queueing
 * it would put a pending row behind the runner's cursor, where it would sit for
 * ever.
 */
export function stepControlsFor(run, step, steps) {
  const none = { confirm: false, skip: false, retry: false }
  if (!run || !step) return none
  if (isTerminalRun(run.status)) return none

  const parked = isParked(step)
  const furthest = step.phase === run.currentPhase ? lastStartedSeqOf(steps, step.phase) : null

  return {
    confirm: parked,
    skip: parked || step.status === 'pending',
    retry:
      run.status === 'paused' &&
      step.status === 'failed' &&
      step.phase === run.currentPhase &&
      furthest !== null &&
      Number(furthest) === Number(step.seq),
  }
}

// ── The definition form ────────────────────────────────────────────────────

export const BLANK_PHASE_KEY = 'phase'

const nextPhaseKey = (phases) => {
  const used = new Set((phases || []).map((p) => p.key))
  for (let n = 1; n < 100; n++) {
    const key = n === 1 ? BLANK_PHASE_KEY : `${BLANK_PHASE_KEY}-${n}`
    if (!used.has(key)) return key
  }
  return `${BLANK_PHASE_KEY}-${Date.now()}`
}

/**
 * A new step, with its params PREFILLED from the action's declared examples.
 *
 * Every param carries a required `example` — that requirement is the reason this
 * works — so a fresh `core.announce` step arrives with the right keys and
 * plausible values rather than empty. Phase 13 turned the box into a form and
 * this stayed exactly as it was: a form whose fields start at the declared
 * example is a step an author edits rather than one they compose.
 */
export function blankStep(action) {
  const params = {}
  for (const p of action?.params || []) {
    if (p.required || p.example !== undefined) params[p.name] = p.example
  }
  return {
    actionId: action?.id || '',
    label: action?.label || '',
    onFailure: '',
    paramsText: JSON.stringify(params, null, 2),
  }
}

export function blankPhase(phases) {
  return { key: nextPhaseKey(phases), label: 'New phase', steps: [], advance: blankAdvance() }
}

/**
 * The advance gate as the FORM holds it (Phase 5) — three fields that are
 * always present and mostly empty, rather than a discriminated union the form
 * has to rebuild every time the dropdown moves.
 *
 * `kind: ''` is "no condition", which is what nearly every phase is and what
 * every phase was before this. The form keeps a half-typed `on` gate's trigger
 * while the author looks at `after`, because a dropdown that discards what was
 * typed under the other option is one an operator learns to be afraid of.
 */
export function blankAdvance() {
  return { kind: '', after: '30m', on: '', count: 1, ...blankWhere() }
}

/**
 * The `where` predicate as the BUILDER holds it (Phase 13).
 *
 * `whereText` survives beside the rows and is not vestigial: it is what a
 * predicate the builder cannot render is shown as, and what is posted for one.
 * See `whereFormFrom`.
 */
export function blankWhere() {
  return { whereOp: 'and', whereRows: [], whereEditable: true, whereText: '' }
}

export const ADVANCE_KINDS = [
  { value: '', label: 'When its steps are done' },
  { value: 'after', label: 'After a fixed delay' },
  { value: 'on', label: 'When something happens in the game' },
]

/** The stored gate, as the form's fields. */
export function advanceFormFrom(advance) {
  const blank = blankAdvance()
  if (!advance) return blank
  if (advance.after !== undefined) return { ...blank, kind: 'after', after: advance.after }
  return {
    ...blank,
    kind: 'on',
    on: advance.on || '',
    count: advance.count ?? 1,
    ...whereFormFrom(advance.where),
  }
}

/**
 * A stored `where` tree → the builder's flat rows (Phase 13).
 *
 * **This is `conditionRowsFrom` and it is deliberately the same function**, not a
 * second one shaped like it. The grammar behind a phase gate is the engagement
 * condition grammar — the server validates it with `engagement/conditions.js`
 * and renders the diagnosis panel's sentence with the same labels — so an editor
 * here that re-decided what a tree looks like would be the second implementation
 * §I refuses on the read side for exactly this reason.
 *
 * A tree the flat editor cannot hold (`A and (B or C)`) comes back
 * `whereEditable: false` and is SHOWN as its JSON rather than silently
 * flattened: `A and B and C` fires on different events, and an author would have
 * no way to know the save had done it to them.
 */
export function whereFormFrom(where) {
  const blank = blankWhere()
  if (!where) return blank
  const rows = conditionRowsFrom(where)
  return {
    whereOp: rows.op,
    whereRows: rows.rows,
    whereEditable: rows.editable,
    whereText: JSON.stringify(where, null, 2),
  }
}

/** The editor's working state, from what `GET /admin/events/:id` returned. */
export function formFromDefinition(event) {
  const spec = event?.spec || {}
  return {
    title: event?.title || '',
    summary: event?.summary || '',
    body: event?.body || '',
    imageUrl: event?.imageUrl || '',
    seriesId: event?.seriesId ? String(event.seriesId) : '',
    seriesOrder: event?.seriesOrder ?? 0,
    concurrencyKey: event?.concurrencyKey || '',
    graceSeconds: event?.graceSeconds ?? 900,
    timezone: event?.timezone || 'UTC',
    // Whether the public calendar announces it (Phase 14a). `?? true` rather
    // than `|| true`: a definition an operator has deliberately unlisted sends
    // `false`, and `||` would quietly re-list it on the next save.
    listed: event?.listed ?? true,
    // Whether the public calendar announces it (Phase 14a). `?? true` rather
    // than `|| true`: a definition an operator has deliberately unlisted sends
    // `false`, and `||` would quietly re-list it on the next save.
    listed: event?.listed ?? true,
    ...scheduleFormFrom(spec.schedule),
    phases: (spec.phases || []).map((p) => ({
      key: p.key || '',
      label: p.label || '',
      advance: advanceFormFrom(p.advance),
      steps: (p.steps || []).map((s) => ({
        actionId: s.actionId || '',
        label: s.label || '',
        onFailure: s.onFailure || '',
        dormant: Boolean(s.dormant),
        actionVersion: s.actionVersion,
        paramsText: JSON.stringify(s.params || {}, null, 2),
      })),
    })),
  }
}

/**
 * One phase's advance gate, as the spec shape — or null when it has none.
 *
 * **Whether the predicate is VALID is still the server's answer.** The builder
 * coerces each literal to the type the trigger DECLARED — which is not a second
 * validator but the thing that makes the first one's error useful: every value
 * in an HTML input is a string, and `{ cmp: 'gt', value: \"5\" }` against an `int`
 * variable is refused by `engagement/conditions.js`, rightly, at which point the
 * author is reading an error about JSON rather than about what they typed.
 *
 * A predicate the builder could not render round-trips through `whereText`
 * unchanged. That is the point of keeping the text: the alternative to posting it
 * back verbatim is dropping an author's tree because this screen could not draw
 * it.
 */
export function advancePayload(advance, where, errors, variables = []) {
  if (!advance || !advance.kind) return null
  if (advance.kind === 'after') return { after: advance.after }

  const out = { on: advance.on, count: Number(advance.count) || 1 }
  if (advance.whereEditable === false) {
    const text = String(advance.whereText || '').trim()
    if (text) {
      try {
        out.where = JSON.parse(text)
      } catch (err) {
        errors.push(`${where}, advance condition: ${err.message}`)
      }
    }
    return out
  }

  const built = conditionsFromRows(advance.whereOp || 'and', advance.whereRows || [], variables)
  if (built) out.where = built
  return out
}

/**
 * The form, as a request body — or the list of everything wrong with it.
 *
 * Only the JSON parse is checked here, and only because a params box whose text
 * is not JSON cannot be turned into a request at all. **Everything else is left
 * to the server**: unknown params, wrong types, missing required ones, bad phase
 * keys and duplicate keys all come back from `POST`/`PUT` as a list, and
 * re-deciding any of them here would be a second validator drifting from the one
 * that matters.
 *
 * `onFailure` is omitted when the author has not chosen one, so the server
 * applies the action's risk-class default rather than being told a value the
 * form invented.
 */
export function payloadFromForm(form, { triggersById = new Map() } = {}) {
  const errors = []
  const phases = (form.phases || []).map((phase, pi) => {
    const where = advancePayload(
      phase.advance,
      `Phase ${pi + 1} "${phase.label || phase.key}"`,
      errors,
      // The declared types the builder coerces against. A trigger nothing
      // registers has none, and every literal then stays the string it was typed
      // as — which is right: the gate is dormant, the server carries its `where`
      // through unvalidated, and inventing types for it here would edit a
      // predicate nobody can currently check.
      triggersById.get(phase.advance?.on)?.variables || [],
    )
    return {
    key: phase.key,
    label: phase.label,
    // Omitted rather than sent as null when there is no gate, which is what
    // `events/spec.js` stores for the same reason: a spec full of
    // `"advance": null` makes the first phase to gain one look like an edit to
    // every phase in the version diff.
    ...(where ? { advance: where } : {}),
    steps: (phase.steps || []).map((step, si) => {
      const out = { actionId: step.actionId }
      if (step.label) out.label = step.label
      if (step.onFailure) out.onFailure = step.onFailure
      const parsed = parseParams(step.paramsText)
      if (parsed.error) {
        errors.push(`Phase ${pi + 1} "${phase.label || phase.key}", step ${si + 1}: ${parsed.error}`)
      } else {
        out.params = parsed.params
      }
      return out
    }),
    }
  })

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

  return {
    ok: true,
    payload: {
      title: form.title,
      summary: form.summary || null,
      body: form.body || null,
      imageUrl: form.imageUrl || null,
      seriesId: form.seriesId ? Number(form.seriesId) : null,
      seriesOrder: Number(form.seriesOrder) || 0,
      concurrencyKey: form.concurrencyKey || null,
      graceSeconds: Number(form.graceSeconds),
      timezone: form.timezone,
      listed: Boolean(form.listed),
      listed: Boolean(form.listed),
      spec: { schedule: scheduleFromForm(form), phases },
    },
  }
}


// ── The schedule (Phase 4) ─────────────────────────────────────────────────
//
// The four closed shapes of §E, mirrored so the form can render one and the
// preview can describe it. `events/spec.js` and `events/recurrence.js` remain
// the deciders — this is what makes the form a form rather than a text box, and
// it is the whole reason the schedule is not a cron string: a closed set has a
// dropdown, and an operator can proofread a dropdown.

export const WEEKDAYS = [
  'sunday',
  'monday',
  'tuesday',
  'wednesday',
  'thursday',
  'friday',
  'saturday',
]

export const SCHEDULE_KINDS = [
  { value: 'manual', label: 'Started by hand' },
  { value: 'once', label: 'Once, at a set time' },
  { value: 'weekly', label: 'Weekly, on chosen days' },
  { value: 'monthly', label: 'Monthly, on the nth weekday' },
]

// 1..4 and "last". There is no fifth: every month has a first through fourth of
// every weekday, and "last" is what a month with five Fridays makes different
// from "fourth" (org lead, 2026-09-02).
export const MONTHLY_NTHS = [
  { value: 1, label: 'First' },
  { value: 2, label: 'Second' },
  { value: 3, label: 'Third' },
  { value: 4, label: 'Fourth' },
  { value: -1, label: 'Last' },
]

const capitalise = (s) => String(s || '').charAt(0).toUpperCase() + String(s || '').slice(1)

/**
 * A schedule in words, in the event's own zone.
 *
 * The server says the same thing in `events/recurrence.js#describe`, and the two
 * are allowed to differ on wording but not on meaning — this one is what an
 * author reads while they are still typing, before anything has been saved.
 */
export function describeSchedule(schedule, timezone = 'UTC') {
  if (!schedule || typeof schedule !== 'object') return 'No schedule'
  const nth = MONTHLY_NTHS.find((n) => n.value === Number(schedule.nth))
  switch (schedule.kind) {
    case 'manual':
      return 'Started by hand — nothing happens until an admin presses Start'
    case 'once': {
      if (!schedule.at) return 'Once — no date chosen yet'
      return `Once, on ${String(schedule.at).replace('T', ' at ')} (${timezone})`
    }
    case 'weekly': {
      const days = (schedule.days || []).map(capitalise)
      if (!days.length || !schedule.time) return 'Weekly — choose days and a time'
      const list =
        days.length === 1
          ? days[0]
          : `${days.slice(0, -1).join(', ')} and ${days[days.length - 1]}`
      return `Every ${list} at ${schedule.time} (${timezone})`
    }
    case 'monthly': {
      if (!nth || !schedule.weekday || !schedule.time) {
        return 'Monthly — choose a week, a weekday and a time'
      }
      return `The ${nth.label.toLowerCase()} ${capitalise(schedule.weekday)} of every month at ${schedule.time} (${timezone})`
    }
    default:
      return 'No schedule'
  }
}

/**
 * The schedule half of the editor's working state.
 *
 * Every shape's fields are kept side by side rather than cleared when the kind
 * changes, so an author who clicks Weekly, then Monthly, then back has not lost
 * the days they picked. `scheduleFromForm` reads only the fields the chosen kind
 * uses, which is what keeps the request body a clean single shape.
 */
export function scheduleFormFrom(schedule) {
  const s = schedule || {}
  return {
    scheduleKind: s.kind || 'manual',
    scheduleAt: s.kind === 'once' ? s.at || '' : '',
    scheduleDays: s.kind === 'weekly' ? s.days || [] : [],
    scheduleNth: s.kind === 'monthly' ? String(s.nth) : '1',
    scheduleWeekday: s.kind === 'monthly' ? s.weekday || 'friday' : 'friday',
    scheduleTime: s.kind === 'weekly' || s.kind === 'monthly' ? s.time || '20:00' : '20:00',
  }
}

/** The schedule the form describes, as the spec object the server expects. */
export function scheduleFromForm(form) {
  switch (form.scheduleKind) {
    case 'once':
      return { kind: 'once', at: form.scheduleAt }
    case 'weekly':
      return { kind: 'weekly', days: form.scheduleDays || [], time: form.scheduleTime }
    case 'monthly':
      return {
        kind: 'monthly',
        nth: Number(form.scheduleNth),
        weekday: form.scheduleWeekday,
        time: form.scheduleTime,
      }
    default:
      return { kind: 'manual' }
  }
}

/**
 * What a calendar entry is, and therefore what may be done with it.
 *
 * A `run` is a row: it has a console and somebody can cancel it. A `projected`
 * entry is arithmetic the runner has not reached yet — there is nothing to open
 * and nothing to stop, and an operator who treats one as a booking has been
 * misled by the UI rather than by the server.
 */
export const isProjected = (entry) => entry?.kind === 'projected'

/** An empty box is `{}`, not a parse error — a step may legitimately take none. */
export function parseParams(text) {
  const raw = (text || '').trim()
  if (!raw) return { params: {} }
  let value
  try {
    value = JSON.parse(raw)
  } catch (err) {
    return { error: `the params are not valid JSON (${err.message})` }
  }
  if (value === null || typeof value !== 'object' || Array.isArray(value)) {
    return { error: 'the params must be a JSON object' }
  }
  return { params: value }
}

// ── Step params, as a form (Phase 13) ─────────────────────────────
//
// §I: the step editor is *"the condition builder, exactly — core serves a
// catalog, the module declared the schema, core renders a form it does not
// understand"*. Phase 3 shipped the raw JSON box as an explicit placeholder for
// this, and everything the form needs was already in the catalog: a param's
// name, type, whether it is required, its description, its example, and the
// option source behind it.
//
// **The JSON stays as the storage and as the escape hatch, and both halves of
// that matter.** As storage, because `payloadFromForm` already builds a request
// out of it and a second representation would be two things to keep in step. As
// an escape hatch, because a form can only render what the declaration
// describes — and a step may legitimately hold something it does not.
//
// The rule for when the form gives way is the CONDITION BUILDER'S rule, which is
// the reason this reads as a port of it rather than as a new idea: a value the
// editor cannot round-trip is SHOWN rather than silently rewritten. Flattening
// `A and (B or C)` there and dropping an undeclared param here are the same
// mistake — a save that looks clean and means something else.

/** The two ways a step's params are edited. */
export const PARAM_FORM = 'form'
export const PARAM_JSON = 'json'

/**
 * Can this step's params be rendered as a form without losing anything?
 *
 * `{ ok: true }`, or `{ ok: false, reason }` naming what the form cannot hold.
 * Three things make one, and none of them is an error — each is a step that has
 * to be edited as JSON:
 *
 *   • **the action is dormant.** There is no declaration, so there are no fields.
 *     A form here would render nothing and look like a step with no params.
 *   • **a param the action does not declare.** The save refuses it by name, which
 *     is what the author needs to see — and a form that dropped it would post a
 *     step that saves cleanly having deleted something they typed.
 *   • **a value no single control can hold** — an object or an array against a
 *     scalar declaration.
 */
export function paramsRenderable(action, params) {
  if (!action) return { ok: false, reason: 'the module that registered this action is not installed' }
  const declared = new Map((action.params || []).map((p) => [p.name, p]))
  for (const [name, value] of Object.entries(params || {})) {
    if (!declared.has(name)) {
      return { ok: false, reason: `this step carries "${name}", which ${action.id} does not declare` }
    }
    if (value !== null && typeof value === 'object') {
      return { ok: false, reason: `"${name}" holds a ${Array.isArray(value) ? 'list' : 'structure'}, which no single field can hold` }
    }
  }
  return { ok: true }
}

/**
 * Which mode should this step open in?
 *
 * The author's own choice wins whenever the form COULD render the step — an
 * author who switched to JSON stays in JSON. What they cannot do is stay in a
 * form that would lose something, so an unrenderable step is forced to JSON
 * whatever the choice was, and the reason is returned so the screen can say it.
 */
export function paramsMode(step, action) {
  const parsed = parseParams(step?.paramsText)
  if (parsed.error) return { mode: PARAM_JSON, forced: true, reason: parsed.error }
  const renderable = paramsRenderable(action, parsed.params)
  if (!renderable.ok) return { mode: PARAM_JSON, forced: true, reason: renderable.reason }
  return { mode: step?.paramsMode === PARAM_JSON ? PARAM_JSON : PARAM_FORM, forced: false, reason: null }
}

/** One declared param's current value, as the control holds it. */
export function paramValue(step, name) {
  const parsed = parseParams(step?.paramsText)
  if (parsed.error) return undefined
  return parsed.params[name]
}

/**
 * Write one param, and give back the whole box.
 *
 * **An empty field REMOVES the key rather than posting an empty string**, and
 * that is the server's own reading rather than a convenience: `checkParams`
 * treats `undefined`, `null` and `''` alike — absent — so a required param left
 * blank comes back as *"is required"*, which is the error the author needs,
 * instead of as a type complaint about `""`.
 *
 * **A value that does not parse is passed through as typed.** `coerceLiteral` is
 * the engagement builder's, unchanged, and its rule is the one that matters
 * here too: half of `-` is not a number, and turning it into `NaN` or `0` while
 * somebody is still typing would either post a value they never wrote or make
 * the field impossible to type a negative into. The server's type check then
 * names the param.
 *
 * Re-serialising the whole object rather than splicing text, for `pickParam`'s
 * reason: a string edit that produced valid-looking JSON with a duplicate key
 * would be a value the editor and the server read differently.
 */
export function setParam(step, name, raw, type) {
  const parsed = parseParams(step?.paramsText)
  if (parsed.error) return step?.paramsText || '{}'
  const next = { ...parsed.params }
  if (raw === '' || raw === undefined || raw === null) delete next[name]
  else next[name] = coerceLiteral(type, raw)
  return JSON.stringify(next, null, 2)
}

/**
 * A stored `datetime` as a `datetime-local` input wants it, and back.
 *
 * The server normalises a datetime param to an ISO string (`conditions.js`
 * `checkLiteral`), and the input needs `YYYY-MM-DDTHH:mm` with no zone. The
 * slice is the whole conversion in one direction; in the other the input's own
 * text is a moment `new Date()` parses, so it is posted as typed and the server
 * does the normalising — one implementation of what a datetime is, and it is
 * not this one.
 */
export const datetimeInputValue = (value) => (typeof value === 'string' ? value.slice(0, 16) : '')

/**
 * Everything the meter needs out of the form, and nothing else.
 *
 * The price route takes a spec, not a definition: no title, no schedule, no
 * series. Sending the whole payload would put a document in front of a route
 * that reads two fields of it — and would fail the moment the rest of the form
 * is mid-edit, which is exactly when the meter is being read.
 *
 * A step whose params do not parse is sent with none rather than dropped, so a
 * half-typed JSON box costs its own step's draw and not the phase's.
 */
export function priceBodyFrom(form) {
  return {
    phases: (form?.phases || []).map((phase) => ({
      key: phase.key || null,
      steps: (phase.steps || []).map((step) => ({
        actionId: step.actionId || '',
        params: parseParams(step.paramsText).params || {},
      })),
    })),
  }
}

/**
 * Is this plan worth pricing at all?
 *
 * A meter that fires on an empty form asks the server what nothing costs, on
 * every keystroke of the title field. One step with an action chosen is the
 * threshold, because that is the first moment there is an answer.
 */
export const worthPricing = (form) =>
  (form?.phases || []).some((p) => (p.steps || []).some((s) => s.actionId))

// ── Rendering what happened ────────────────────────────────────────────────

const STATUS_WORDS = {
  scheduled: 'Scheduled',
  starting: 'Starting',
  running: 'Running',
  paused: 'Paused',
  ending: 'Winding down',
  completed: 'Completed',
  cancelled: 'Cancelled',
  failed: 'Failed',
  missed: 'Missed',
}

export const runStatusWord = (status) => STATUS_WORDS[status] || status || 'unknown'

const KIND_WORDS = {
  'run.created': 'Occurrence created',
  'run.status': 'Run status',
  'run.health': 'Health',
  'run.blocked': 'Held off',
  'phase.entered': 'Phase entered',
  'phase.completed': 'Phase completed',
  'step.status': 'Step',
  'step.retry': 'Step retried',
  'step.parked': 'Waiting on a human',
  'phase.gate': 'Advance condition set',
  'condition.evaluated': 'Condition evaluated',
  'phase.advanced': 'Phase advanced',
  // Phase 6. "Refused" reads differently from "Step" on purpose: an operator
  // scanning a stopped run needs to see that nothing is broken.
  'step.refused': 'Refused',
  'run.budget': 'Caps',
  'version.verified': 'Dry run passed',
  note: 'Note',
}

export const logKindWord = (kind) => KIND_WORDS[kind] || kind

/**
 * One log line as a sentence.
 *
 * The `detail` of a human control carries `control` and `by`, which is what
 * separates "the runner paused this because a world write failed" from "somebody
 * pressed pause" — the two are the same transition and the console has to be
 * able to tell them apart at a glance.
 */
export function describeLogLine(line) {
  const d = line?.detail || {}
  const by = d.by ? ' by staff' : ''
  switch (line?.kind) {
    case 'run.status':
      return d.control
        ? `${runStatusWord(d.to)}${by} — ${d.control}${d.reason ? `: ${d.reason}` : ''}`
        : `${d.from ? `${runStatusWord(d.from)} → ` : ''}${runStatusWord(d.to)}${d.because ? ` (${d.because})` : ''}`
    case 'run.health':
      return `Health is now ${d.to}${d.because ? ` (${d.because})` : ''}`
    case 'run.blocked':
      return `Held: run ${d.heldBy} has the concurrency key "${d.concurrencyKey}"`
    case 'phase.entered':
      return `Entered ${line.phase} (${d.steps ?? '?'} steps)`
    case 'phase.completed':
      return `${line.phase} finished`
    case 'step.parked':
      return `${d.action} is waiting on a human`
    case 'step.retry':
      return `${d.action} failed, attempt ${d.attempt} of ${d.of}${d.error ? `: ${d.error}` : ''}`
    case 'step.status':
      return d.control
        ? `${d.action} → ${d.to}${by} — ${d.control}${d.note || d.reason ? `: ${d.note || d.reason}` : ''}`
        : `${d.action} → ${d.to}${d.error ? `: ${d.error}` : ''}`
    case 'run.created':
      return `Occurrence created from version ${d.version}${d.rehearsal ? ' (rehearsal)' : ''}`
    case 'phase.gate':
      return d.kind === 'after'
        ? `${line.phase} advances ${d.after} after it started`
        : `${line.phase} advances on ${d.needed} × ${d.trigger}${d.where ? ` where ${d.where}` : ''}`
    // Both outcomes are logged, and the near miss is the useful one: it is the
    // difference between "the boss did spawn, in the wrong region" and "no boss
    // has spawned", which look identical on every other line of this log.
    case 'condition.evaluated':
      return `${d.trigger} ${d.matched ? 'counted' : 'did not count'} — ${d.seen} of ${d.needed}${
        d.satisfied ? ', condition met' : ''
      }`
    case 'phase.advanced':
      return d.because === 'forced'
        ? `${line.phase} advanced by hand after ${d.waitedSeconds}s${d.reason ? `: ${d.reason}` : ''}`
        : `${line.phase} advanced on its ${d.because === 'elapsed' ? 'deadline' : 'condition'} after ${d.waitedSeconds}s`
    // Phase 6. `step.refused` is its own kind rather than a `step.status` for a
    // reason an operator feels at 2am: a refusal is not a failure, and the line
    // has to say which deployment rule stopped it -- the answer to "not enabled"
    // is a switch, and the answer to "over the cap" is a number.
    case 'step.refused':
      return `${d.action} refused: ${d.error}`
    case 'run.budget':
      return (d.dimensions || [])
        .map((x) => `${x.dimension} capped at ${x.cap === null ? 'nothing' : x.cap}${x.from ? ` (${x.from})` : ''}`)
        .join(', ') || 'no caps apply to this run'
    case 'version.verified':
      return `Version ${d.version} passed its dry run — scheduled occurrences may start`
    default:
      return logKindWord(line?.kind)
  }
}