import Link from 'next/link'
import { Card } from '@/libs/frontend-ui-primitives'
import EntityBadge from '@/components/common/EntityBadge'
import type { ChainActivityContext } from '@/utils/activityContext'
import { formatRelativeAge, formatTimestamp } from '@/utils/format'
import { Explain, useUiMode } from './UiModeContext'

function resolveTone(state: ChainActivityContext['state']): 'success' | 'warning' | 'neutral' {
  switch (state) {
    case 'active':
      return 'success'
    case 'low':
    case 'inactive':
      return 'warning'
    default:
      return 'neutral'
  }
}

function resolveLabel(state: ChainActivityContext['state']): string {
  switch (state) {
    case 'active':
      return 'active'
    case 'low':
      return 'low activity'
    case 'inactive':
      return 'inactive'
    default:
      return 'unknown'
  }
}

function renderHeadline(context: ChainActivityContext): string {
  if (context.transaction_visibility_unavailable) {
    return 'Transaction index freshness is currently unavailable, while chain-head visibility remains live.'
  }
  if (context.state === 'unknown') {
    return 'Recent activity context is temporarily unavailable.'
  }
  if (context.state === 'active') {
    return 'Recent transactions are close to the visible chain tip.'
  }
  if (context.head_is_idle) {
    return 'The chain head is advancing, but the latest visible transaction is older than the current tip.'
  }
  return 'Recent transaction activity is sparse right now.'
}

export default function ActivityContextPanel({
  context,
  title = 'Chain Activity Context',
}: {
  context: ChainActivityContext
  title?: string
}) {
  const { mode } = useUiMode()
  const tone = resolveTone(context.state)
  const dualTimelineLabel =
    context.latest_block_timestamp && context.latest_transaction_timestamp
      ? `${formatRelativeAge(context.latest_block_timestamp)} head · ${formatRelativeAge(context.latest_transaction_timestamp)} latest tx`
      : 'Dual timeline unavailable'

  return (
    <Card className="border border-sky-200 bg-sky-50/60 dark:border-sky-900/40 dark:bg-sky-950/20" title={title}>
      <div className="flex flex-col gap-4">
        <div className="flex flex-col gap-3 lg:flex-row lg:items-start lg:justify-between">
          <div>
            <div className="text-base font-semibold text-gray-900 dark:text-white">{renderHeadline(context)}</div>
            <Explain>
              <p className="mt-2 text-sm leading-6 text-gray-600 dark:text-gray-400">
                Use the transaction tip and last non-empty block below to distinguish a quiet chain from a broken explorer.
              </p>
            </Explain>
          </div>
          <EntityBadge label={resolveLabel(context.state)} tone={tone} />
        </div>

        <div className="grid gap-3 sm:grid-cols-2 xl:grid-cols-4">
          <div className="rounded-2xl border border-white/50 bg-white/70 p-4 dark:border-white/10 dark:bg-black/10">
            <div className="text-xs font-semibold uppercase tracking-wide text-gray-500 dark:text-gray-400">Latest Block</div>
            <div className="mt-2 text-xl font-semibold text-gray-900 dark:text-white">
              {context.latest_block_number != null ? `#${context.latest_block_number}` : 'Unknown'}
            </div>
            <div className="mt-1 text-sm text-gray-600 dark:text-gray-400">
              {formatRelativeAge(context.latest_block_timestamp)}
            </div>
          </div>
          <div className="rounded-2xl border border-white/50 bg-white/70 p-4 dark:border-white/10 dark:bg-black/10">
            <div className="text-xs font-semibold uppercase tracking-wide text-gray-500 dark:text-gray-400">Latest Transaction</div>
            <div className="mt-2 text-xl font-semibold text-gray-900 dark:text-white">
              {context.latest_transaction_block_number != null ? `#${context.latest_transaction_block_number}` : 'Unknown'}
            </div>
            <div className="mt-1 text-sm text-gray-600 dark:text-gray-400">
              {formatRelativeAge(context.latest_transaction_timestamp)}
            </div>
          </div>
          <div className="rounded-2xl border border-white/50 bg-white/70 p-4 dark:border-white/10 dark:bg-black/10">
            <div className="text-xs font-semibold uppercase tracking-wide text-gray-500 dark:text-gray-400">Last Non-Empty Block</div>
            <div className="mt-2 text-xl font-semibold text-gray-900 dark:text-white">
              {context.last_non_empty_block_number != null ? `#${context.last_non_empty_block_number}` : 'Unknown'}
            </div>
            <div className="mt-1 text-sm text-gray-600 dark:text-gray-400">
              {formatRelativeAge(context.last_non_empty_block_timestamp)}
            </div>
          </div>
          <div className="rounded-2xl border border-white/50 bg-white/70 p-4 dark:border-white/10 dark:bg-black/10">
            <div className="text-xs font-semibold uppercase tracking-wide text-gray-500 dark:text-gray-400">Block Gap</div>
            <div className="mt-2 text-xl font-semibold text-gray-900 dark:text-white">
              {context.block_gap_to_latest_transaction != null ? context.block_gap_to_latest_transaction.toLocaleString() : 'Unknown'}
            </div>
            <div className="mt-1 text-sm text-gray-600 dark:text-gray-400">
              {mode === 'guided'
                ? 'Difference between the current tip and the latest visible transaction block.'
                : dualTimelineLabel}
            </div>
          </div>
        </div>

        <div className="flex flex-wrap gap-4 text-sm text-gray-600 dark:text-gray-400">
          {context.latest_transaction_block_number != null ? (
            <Link href={`/blocks/${context.latest_transaction_block_number}`} className="text-primary-600 hover:underline">
              Open latest transaction block →
            </Link>
          ) : null}
          {context.last_non_empty_block_number != null ? (
            <Link href={`/blocks/${context.last_non_empty_block_number}`} className="text-primary-600 hover:underline">
              Open last non-empty block →
            </Link>
          ) : null}
          {context.latest_transaction_timestamp ? (
            <span>Latest visible transaction time: {formatTimestamp(context.latest_transaction_timestamp)}</span>
          ) : null}
        </div>
      </div>
    </Card>
  )
}