import { useState } from 'react'
import { Link } from 'react-router-dom'
import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query'
import { Icon, ruleIcon } from '../components/Icon'
import { Empty, PageHead, SkeletonLines, SkeletonRows } from '../components/Page'
import { toast } from '../components/Toast'
import { describeRule } from '../express/parse'
import { locale, t, type Key } from '../i18n'
import {
  archiveSchedule, confirmProduction, isMine, isRunSchedule, knowledgeReadiness, listRuns, listSchedules, scheduleOwners, pauseSchedule, PLAN_ACTIVE, productionStatus, quoteProduction, resumeSchedule,
  planProgress, productionError, runNow as startRun, updateTopic, type ContentPlan, type Owners, type RunSummary, type Schedule,
} from '../express/schedules'

const STUDIO_URL: string = import.meta.env.VITE_STUDIO_URL

const fmt = (iso: string | null | undefined) => (iso
  ? new Intl.DateTimeFormat(locale(), { weekday: 'short', day: 'numeric', month: 'short', hour: '2-digit', minute: '2-digit' }).format(new Date(iso))
  : '–')

const RUN_STATUSES = new Set(['queued', 'planning', 'running', 'completed', 'failed', 'cancelled', 'paused_configuration', 'paused_budget'])
const runStatus = (s: string) => (RUN_STATUSES.has(s) ? t(`run.${s}` as Key) : s)
const RUN_ERRORS = new Set([
  'knowledge_not_ready', 'video_sources_unavailable', 'material_sources_unavailable', 'knowledge_search_failed',
  'organization_wallet', 'run_cap', 'monthly_cap', 'reservation_cap', 'price_changed', 'video_price_changed',
  'agent_not_active', 'run_access_revoked', 'required_tool_unavailable',
])
const ISSUE_REASONS = new Set([
  'document_processing', 'document_failed', 'graph_building', 'graph_not_ready', 'legacy_set_needs_conversion',
  'no_knowledge_sources', 'source_not_accessible', 'source_graph_not_ready', 'source_version_changed', 'snapshot_not_ready',
])
const WAITING_REASONS = new Set(['document_processing', 'graph_building', 'snapshot_not_ready'])
const runError = (code: string) => (RUN_ERRORS.has(code) ? t(`runErr.${code}` as Key) : code)
const issueReason = (reason: string) => (ISSUE_REASONS.has(reason) ? t(`issue.${reason}` as Key) : reason)
const isNotReady = (r: RunSummary) => r.safe_error_code === 'knowledge_not_ready' || r.has_readiness_issues

// Which schedules the page starts with; remembered per device.
type Scope = 'mine' | 'all'
const SCOPE_KEY = 'express.scheduleScope'
const savedScope = (): Scope => {
  try { return localStorage.getItem(SCOPE_KEY) === 'all' ? 'all' : 'mine' } catch { return 'mine' }
}

export function SchedulePage() {
  const schedules = useQuery({ queryKey: ['schedules'], queryFn: listSchedules, refetchInterval: 30_000 })
  const owners = useQuery({ queryKey: ['scheduleOwners'], queryFn: scheduleOwners, staleTime: 5 * 60_000 })
  const [scope, setScope] = useState<Scope>(savedScope)
  const choose = (next: Scope) => {
    setScope(next)
    try { localStorage.setItem(SCOPE_KEY, next) } catch { /* keep it for this visit only */ }
  }

  const all = schedules.data
  const mine = all && owners.data ? all.filter(s => isMine(s, owners.data)) : undefined
  // Members only ever see their own, so the switch appears only when someone else's schedules are listed.
  const mixed = !!all && !!mine && mine.length < all.length
  const shown = mixed && scope === 'mine' ? mine : all

  return (
    <>
      <PageHead title={t('sch.title')} description={t('sch.description')}
        actions={<Link className="btn primary" to="/instruction"><Icon name="plus" />{t('sch.newInstruction')}</Link>} />
      {mixed && (
        <div className="result-tabs" role="tablist">
          <button role="tab" aria-selected={scope === 'mine'} className={scope === 'mine' ? 'active' : undefined} onClick={() => choose('mine')}>
            {t('sch.mine')} <b>{mine.length}</b>
          </button>
          <button role="tab" aria-selected={scope === 'all'} className={scope === 'all' ? 'active' : undefined} onClick={() => choose('all')}>
            {t('sch.all')} <b>{all.length}</b>
          </button>
        </div>
      )}
      <div className="card">
        <div className="card-head"><h3>{t('sch.cardTitle')}</h3><Icon name="calendar" /></div>
        {schedules.isPending && <SkeletonRows label={t('sch.loading')} />}
        {schedules.isError && <Empty icon="info" title={t('sch.loadFailed')}>{schedules.error.message}</Empty>}
        {all?.length === 0 && <Empty icon="calendar" title={t('sch.empty')}>{t('sch.emptyCopy')}</Empty>}
        {mixed && shown?.length === 0 && <Empty icon="calendar" title={t('sch.emptyMine')}>{t('sch.emptyMineCopy')}</Empty>}
        {!!shown?.length && <div className="result-list">{shown.map(s => <ScheduleRow key={s.agent.id} schedule={s} owners={owners.data} />)}</div>}
      </div>
    </>
  )
}

function createdBy(schedule: Schedule, owners: Owners) {
  if (isMine(schedule, owners)) return t('sch.byYou')
  const name = schedule.agent.created_by_user_id != null ? owners.names.get(schedule.agent.created_by_user_id) : undefined
  return name ? t('sch.by', { name }) : t('sch.byUnknown')
}

function ScheduleRow({ schedule, owners }: { schedule: Schedule; owners?: Owners }) {
  const { agent, rule, active } = schedule
  const queryClient = useQueryClient()
  const [editing, setEditing] = useState(false)
  const [topic, setTopic] = useState(rule.topic)
  const [open, setOpen] = useState(false)
  const [producing, setProducing] = useState(false)
  const refresh = () => queryClient.invalidateQueries({ queryKey: ['schedules'] })
  const video = rule.type === 'content' && rule.kind === 'video'
  // Content kinds run as weekly production plans; research and video as one run per slot.
  const production = !isRunSchedule(rule)

  const toggle = useMutation({ mutationFn: () => (active ? pauseSchedule(agent.id) : resumeSchedule(schedule)), onSuccess: refresh })
  const retopic = useMutation({ mutationFn: () => updateTopic(schedule, topic), onSuccess: () => { setEditing(false); refresh() } })
  const archive = useMutation({ mutationFn: () => archiveSchedule(agent.id), onSuccess: () => { toast(t('sch.deleted')); refresh() } })
  const runNow = useMutation({
    mutationFn: () => startRun(agent.id),
    onSuccess: () => {
      toast(t(video ? 'sch.videoStarted' : 'sch.runStarted'))
      setOpen(true)
      queryClient.invalidateQueries({ queryKey: ['runs', agent.id] })
      queryClient.invalidateQueries({ queryKey: ['results'] })
    },
  })
  const error = toggle.error ?? retopic.error ?? archive.error ?? runNow.error
  const busy = toggle.isPending || retopic.isPending || archive.isPending || runNow.isPending

  return (
    <div className="schedule-row">
      <div className="result-row">
        <span className="rule-icon"><Icon name={ruleIcon(rule)} /></span>
        <div style={{ minWidth: 0, flex: 1 }}>
          <b>{describeRule(rule)}</b>
          {owners && <div className="schedule-owner"><small><Icon name="user" />{createdBy(schedule, owners)}</small></div>}
          <div><small>{production
            ? <ProductionLine agentId={agent.id} active={active} />
            : t(video ? 'sch.nextVideo' : 'sch.nextResearch', { when: active ? fmt(agent.next_run_at) : t('sch.paused') })}</small></div>
          {editing && (
            <form className="topic-edit" onSubmit={e => { e.preventDefault(); retopic.mutate() }}>
              <input aria-label={t('sch.newTopic')} value={topic} placeholder={t('ins.topicPlaceholder')} autoFocus onChange={e => setTopic(e.target.value)} />
              <button className="btn small primary" disabled={busy}>{t('common.save')}</button>
              <button type="button" className="btn small" onClick={() => { setEditing(false); setTopic(rule.topic) }}>{t('common.cancel')}</button>
            </form>
          )}
          {error && <span className="error">{error.message}</span>}
        </div>
        <span className={`status ${active ? 'ready' : 'draft'}`}><i className="dot"></i>{active ? t('sch.active') : t('sch.paused')}</span>
      </div>
      <div className="schedule-actions">
        {!editing && <button className="btn small" disabled={busy} onClick={() => setEditing(true)}>{t('sch.changeTopic')}</button>}
        <button className="btn small" disabled={busy} onClick={() => toggle.mutate()}>{active ? t('sch.pause') : t('sch.resume')}</button>
        {!production && active && <button className="btn small" disabled={busy} onClick={() => runNow.mutate()}>{t(video ? 'sch.videoNow' : 'sch.runNow')}</button>}
        {production && active && !producing && <button className="btn small" disabled={busy} onClick={() => setProducing(true)}>{t('sch.produceNow')}</button>}
        <button className="btn small" onClick={() => setOpen(o => !o)}>{open ? t('sch.hideHistory') : t('sch.history')}</button>
        <button className="btn small danger" disabled={busy}
          onClick={() => confirm(t('sch.deleteConfirm', { name: describeRule(rule) })) && archive.mutate()}>{t('sch.delete')}</button>
      </div>
      {production && !producing && <ProductionProgress agentId={agent.id} />}
      {producing && production && <ProducePanel schedule={schedule} onClose={() => setProducing(false)} />}
      {open && <RunHistory agentId={agent.id} />}
    </div>
  )
}

// Content schedules report this week's progress from the engine's production period. Each row
// asks for its own, so it is read once a minute; starting a production refreshes it at once.
const useProduction = (agentId: number) => useQuery({
  queryKey: ['production', agentId],
  queryFn: () => productionStatus(agentId),
  refetchInterval: 60_000,
  staleTime: 60_000,
})

function ProductionLine({ agentId, active }: { agentId: number; active: boolean }) {
  const status = useProduction(agentId)
  const s = status.data
  if (!s) return <>{status.isError ? status.error.message : t('sch.loadingProgress')}</>
  if (!s.planning_available) {
    return <span className="error">{t('sch.planningOff')}</span>
  }
  if (!active) return <>{t('sch.paused')}</>
  const p = s.period
  return <>{p ? t('sch.thisWeek', { ready: p.ready, target: p.target, failed: p.failed ? t('sch.thisWeekFailed', { n: p.failed }) : '' }) : t('sch.waitingFirst')}</>
}

// Starts this week's production early: quote the planning step, show its price, then confirm it.
// The latest production of this schedule, step by step: topics → creating → done.
function ProductionProgress({ agentId }: { agentId: number }) {
  const plan = useProduction(agentId).data?.plans[0]
  if (!plan || plan.status === 'quoted' || plan.status === 'cancelled') return null
  const { total, ready, failed, shortfall } = planProgress(plan)
  const step = plan.status === 'planning' ? 0 : plan.status === 'running' || plan.status === 'paused' ? 2 : plan.status === 'completed' ? 3 : 1
  const steps = [t('prod.stepTopics'), t('prod.stepStart'), t('prod.stepCreate', { ready, total }), t('prod.stepDone')]
  const finished = plan.status === 'completed' || plan.status === 'failed'

  return (
    <div className={`production-progress${finished ? ' finished' : ''}`} role="status" aria-live="polite">
      <div className="production-head">
        {!finished && <span className="spinner" aria-hidden="true" />}
        <b>{finished ? t('prod.lastTitle') : t('prod.runningTitle', { n: plan.target })}</b>
        {plan.status !== 'planning' && total > 0 && <span className="production-count">{t('prod.count', { ready, total })}</span>}
      </div>
      {plan.status === 'failed' ? (
        <span className="error">{t('prod.failed', { code: plan.error_code ?? '–' })}</span>
      ) : (
        <ol className="production-steps">
          {steps.map((label, i) => (
            <li key={i} className={i < step ? 'done' : i === step ? (finished ? 'done' : 'current') : undefined}>{label}</li>
          ))}
        </ol>
      )}
      {!!total && plan.status !== 'planning' && <div className="production-bar"><i style={{ width: `${Math.round(((ready + failed) / total) * 100)}%` }} /></div>}
      {(failed > 0 || (shortfall > 0 && plan.status !== 'planning')) && (
        <small>{[failed ? t('prod.someFailed', { n: failed }) : '', shortfall ? t('prod.shortfall', { n: shortfall }) : ''].filter(Boolean).join(' ')}</small>
      )}
      {(ready > 0 || plan.status === 'running') && <Link className="text-btn" to="/results">{t('prod.viewResults')} <Icon name="arrow-right" /></Link>}
    </div>
  )
}

function ProducePanel({ schedule: { agent, rule }, onClose }: { schedule: Schedule; onClose: () => void }) {
  const queryClient = useQueryClient()
  const status = useProduction(agent.id)
  const period = status.data?.period
  const remaining = period ? Math.max(0, period.target - period.claimed) : agent.content_goal?.weekly_target ?? 0
  const [count, setCount] = useState(rule.type === 'content' ? rule.count : 1)
  const n = Math.min(Math.max(1, count), Math.max(1, remaining))
  const quote = useMutation({ mutationFn: () => quoteProduction(agent.id, n) })
  const start = useMutation({
    mutationFn: (plan: ContentPlan) => confirmProduction(agent.id, plan),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['production', agent.id] })
      queryClient.invalidateQueries({ queryKey: ['results'] })
      onClose()
    },
  })
  const error = quote.error ?? start.error
  const running = status.data?.plans.some(p => PLAN_ACTIVE.has(p.status))

  if (status.isPending) return <div className="produce-panel"><SkeletonLines label={t('sch.loadingProgress')} /></div>
  return (
    <div className="produce-panel">
      {running ? (
        <p>{t('sch.alreadyProducing')}</p>
      ) : remaining === 0 ? (
        <p>{t('sch.weekFull')}</p>
      ) : quote.data ? (
        <p>{t('sch.produceQuote', { n: quote.data.target, credits: quote.data.planning_quote.credits ?? 0, budget: agent.content_goal?.weekly_budget ?? 0 })}</p>
      ) : (
        <label>{t('sch.produceHowMany', { max: remaining })}
          <input type="number" min={1} max={remaining} value={n} onChange={e => setCount(Number(e.target.value) || 1)} />
        </label>
      )}
      {error && <span className="error">{productionError(error.message)}</span>}
      <div className="produce-actions">
        {!running && remaining > 0 && (quote.data
          ? <button className="btn small primary" disabled={start.isPending} onClick={() => start.mutate(quote.data)}>{start.isPending ? t('sch.starting') : t('sch.startProduction')}</button>
          : <button className="btn small primary" disabled={quote.isPending} onClick={() => quote.mutate()}>{quote.isPending ? t('sch.checkingPrice') : t('sch.checkPrice')}</button>)}
        <button className="btn small" onClick={onClose}>{running || remaining === 0 ? t('res.close') : t('common.cancel')}</button>
      </div>
    </div>
  )
}

function RunHistory({ agentId }: { agentId: number }) {
  const runs = useQuery({
    queryKey: ['runs', agentId],
    queryFn: () => listRuns(agentId),
    refetchInterval: q => (q.state.data?.some(r => ['queued', 'planning', 'running'].includes(r.status)) ? 3000 : false),
  })
  if (runs.isPending) return <div className="run-history"><SkeletonLines count={3} label={t('sch.loadingHistory')} /></div>
  if (runs.isError) return <div className="run-history"><span className="error">{runs.error.message}</span></div>
  if (!runs.data.length) return <div className="run-history"><small>{t('sch.neverRan')}</small></div>
  const shown = runs.data.slice(0, 8)
  // Readiness is today's state, so it is shown once, under the newest run it stopped.
  const blockedId = shown.find(isNotReady)?.id
  return (
    <ul className="run-history">
      {shown.map(r => (
        <li key={r.id}>
          <span>{fmt(r.created_at)}</span>
          <span>{r.trigger_kind === 'scheduled' ? t('sch.scheduled') : t('sch.manual')}</span>
          <span className={`status ${r.status === 'completed' ? 'ready' : 'draft'}`}><i className="dot"></i>{runStatus(r.status)}</span>
          {r.budget_spent != null && <span>{t('common.credits', { n: r.budget_spent })}</span>}
          {r.safe_error_code && <span className="error" title={r.safe_error_code}>{runError(r.safe_error_code)}</span>}
          {r.source_outcome === 'no_new_sources' && <span>{t('sch.noNewSources')}</span>}
          {r.id === blockedId && <ReadinessIssues agentId={agentId} />}
        </li>
      ))}
    </ul>
  )
}

function ReadinessIssues({ agentId }: { agentId: number }) {
  const readiness = useQuery({
    queryKey: ['readiness', agentId],
    queryFn: () => knowledgeReadiness(agentId),
    // Processing and building finish on their own; keep the list current until they do.
    refetchInterval: q => (q.state.data?.issues.some(i => WAITING_REASONS.has(i.reason)) ? 5000 : false),
  })
  if (readiness.isPending) return <div className="run-issues"><SkeletonLines count={1} label={t('sch.loadingHistory')} /></div>
  if (readiness.isError) return <div className="run-issues"><span className="error">{readiness.error.message}</span></div>
  if (!readiness.data.issues.length) return <div className="run-issues"><small>{t('sch.blockedNone')}</small></div>
  return (
    <div className="run-issues">
      <strong>{t('sch.blockedBy')}</strong>
      <ul>
        {readiness.data.issues.map(issue => (
          <li key={`${issue.kind}-${issue.resource_id}`}>
            <span><b>{issue.title}</b> · {issueReason(issue.reason)}</span>
            <a href={`${STUDIO_URL}${issue.action_url}`} target="_blank" rel="noreferrer">{t('sch.fixInStudio')}</a>
          </li>
        ))}
      </ul>
    </div>
  )
}