import * as React from 'react'
import { useState } from 'react'
import { Text } from '@anthropic/ink'
import { logEvent } from '../../services/analytics/index.js'
import {
  formatGrantAmount,
  getCachedOverageCreditGrant,
  refreshOverageCreditGrantCache,
} from '../../services/api/overageCreditGrant.js'
import { getGlobalConfig, saveGlobalConfig } from '../../utils/config.js'
import { truncate } from '../../utils/format.js'
import type { FeedConfig } from './Feed.js'

const MAX_IMPRESSIONS = 3

/**
 * Whether to show the overage credit upsell on any surface.
 *
 * Eligibility comes entirely from the backend GET /overage_credit_grant
 * response — the CLI doesn't replicate tier/threshold/role checks. The
 * backend returns available: false for Team members who aren't admins,
 * so they don't see an upsell they can't act on.
 *
 * isEligibleForOverageCreditGrant — just the backend eligibility. Use for
 *   persistent reference surfaces (/usage) where the info should show
 *   whenever eligible, no impression cap.
 * shouldShowOverageCreditUpsell — adds the 3-impression cap and
 *   hasVisitedExtraUsage dismiss. Use for promotional surfaces
 *   (welcome feed, tips).
 */
export function isEligibleForOverageCreditGrant(): boolean {
  const info = getCachedOverageCreditGrant()
  if (!info || !info.available || info.granted) return false
  return formatGrantAmount(info) !== null
}

export function shouldShowOverageCreditUpsell(): boolean {
  if (!isEligibleForOverageCreditGrant()) return false

  const config = getGlobalConfig()
  if (config.hasVisitedExtraUsage) return false
  if ((config.overageCreditUpsellSeenCount ?? 0) >= MAX_IMPRESSIONS)
    return false

  return true
}

/**
 * Kick off a background fetch if the cache is empty. Safe to call
 * unconditionally on mount — it no-ops if cache is fresh.
 */
export function maybeRefreshOverageCreditCache(): void {
  if (getCachedOverageCreditGrant() !== null) return
  void refreshOverageCreditGrantCache()
}

export function useShowOverageCreditUpsell(): boolean {
  const [show] = useState(() => {
    maybeRefreshOverageCreditCache()
    return shouldShowOverageCreditUpsell()
  })
  return show
}

export function incrementOverageCreditUpsellSeenCount(): void {
  let newCount = 0
  saveGlobalConfig(prev => {
    newCount = (prev.overageCreditUpsellSeenCount ?? 0) + 1
    return {
      ...prev,
      overageCreditUpsellSeenCount: newCount,
    }
  })
  logEvent('tengu_overage_credit_upsell_shown', { seen_count: newCount })
}

// Copy from "OC & Bulk Overages copy" doc (#6 — CLI /usage)
function getUsageText(amount: string): string {
  return `${amount} in extra usage for third-party apps · /extra-usage`
}

// Copy from "OC & Bulk Overages copy" doc (#4 — CLI Welcome screen).
// Char budgets: title ≤19, subtitle ≤48.
const FEED_SUBTITLE = 'On us. Works on third-party apps · /extra-usage'

function getFeedTitle(amount: string): string {
  return `${amount} in extra usage`
}

type Props = { maxWidth?: number; twoLine?: boolean }

export function OverageCreditUpsell({
  maxWidth,
  twoLine,
}: Props): React.ReactNode {
  const info = getCachedOverageCreditGrant()
  if (!info) return null
  const amount = formatGrantAmount(info)
  if (!amount) return null

  if (twoLine) {
    const title = getFeedTitle(amount)
    return (
      <>
        <Text color="claude">
          {maxWidth ? truncate(title, maxWidth) : title}
        </Text>
        <Text dimColor>
          {maxWidth ? truncate(FEED_SUBTITLE, maxWidth) : FEED_SUBTITLE}
        </Text>
      </>
    )
  }

  const text = getUsageText(amount)
  const display = maxWidth ? truncate(text, maxWidth) : text
  const highlightLen = Math.min(getFeedTitle(amount).length, display.length)

  return (
    <Text dimColor>
      <Text color="claude">{display.slice(0, highlightLen)}</Text>
      {display.slice(highlightLen)}
    </Text>
  )
}

/**
 * Feed config for the homescreen rotating feed. Mirrors
 * createGuestPassesFeed in feedConfigs.tsx.
 *
 * Copy from "OC & Bulk Overages copy" doc (#4 — CLI Welcome screen).
 * Char budgets: title ≤19, subtitle ≤48.
 */
export function createOverageCreditFeed(): FeedConfig {
  const info = getCachedOverageCreditGrant()
  const amount = info ? formatGrantAmount(info) : null
  const title = amount ? getFeedTitle(amount) : 'extra usage credit'
  return {
    title,
    lines: [],
    customContent: {
      content: <Text dimColor>{FEED_SUBTITLE}</Text>,
      width: Math.max(title.length, FEED_SUBTITLE.length),
    },
  }
}