"use client"

import { useMemo, useState, type ReactNode } from "react"
import {
  Alert,
  AlertDescription,
  AlertTitle,
} from "@/components/reui/alert"
import { Badge } from "@/components/reui/badge"
import { Frame, FramePanel } from "@/components/reui/frame"
import { Button } from "@/components/ui/button"
import { ScrollArea } from "@/components/ui/scroll-area"
import {
  Sheet,
  SheetClose,
  SheetContent,
  SheetDescription,
  SheetFooter,
  SheetHeader,
  SheetTitle,
} from "@/components/ui/sheet"
import { Tabs, TabsList, TabsTrigger } from "@/components/ui/tabs"
import {
  CheckIcon,
  CopyIcon,
  DownloadIcon,
  LoaderCircleIcon,
  RefreshCwIcon,
  TriangleAlertIcon,
} from "lucide-react"
import { cn } from "@/lib/utils"
import { toast } from "sonner"

export type CodeExportFormat = {
  id: string
  label: string
  filename: string
  code: string
  /** Empty / unavailable — show warning instead of code */
  emptyMessage?: string
  /** Content came from live device fetch */
  isLive?: boolean
}

function downloadText(filename: string, content: string) {
  const blob = new Blob([content], { type: "text/plain;charset=utf-8" })
  const url = URL.createObjectURL(blob)
  const a = document.createElement("a")
  a.href = url
  a.download = filename
  a.click()
  URL.revokeObjectURL(url)
}

function highlightLine(line: string): string {
  const trimmed = line.trimStart()
  if (line.startsWith("#") || trimmed.startsWith(";")) return "text-muted-foreground"
  if (trimmed.startsWith("[")) return "text-info"
  if (trimmed.startsWith("/")) return "text-info"
  if (/^\s+[a-zA-Z]/.test(line) || /^[A-Za-z][\w-]*=/.test(line)) return "text-foreground"
  return "text-foreground/90"
}

function CodeBlock({ code, className }: { code: string; className?: string }) {
  const lines = code.length ? code.split("\n") : [""]
  return (
    <pre className={cn("px-4 py-3.5 text-[12px] font-mono leading-[1.65] whitespace-pre-wrap break-all select-all", className)}>
      {lines.map((line, i) => (
        <span key={i} className={cn("block", highlightLine(line))}>
          {line || " "}
        </span>
      ))}
    </pre>
  )
}

export interface CodeExportSheetProps {
  open: boolean
  onClose: () => void
  title: string
  description?: ReactNode
  formats: CodeExportFormat[]
  /** Initial format id when sheet opens */
  initialFormatId?: string
  /** Optional live fetch from device */
  onLiveFetch?: (formatId: string) => void
  liveBusy?: boolean
  /** Short CTA — keep laconic */
  liveLabel?: string
  className?: string
  /** Extra content under format tabs (e.g. meta strip) */
  returnFocus?: () => HTMLElement | null
  beforeCode?: ReactNode
}

/**
 * Shared code export Sheet — ReUI Frame + sticky footer.
 * Preview DNA: https://reui.io/preview/base/sheet-8 · Frame https://reui.io/docs/components/base/frame
 * Alert: https://reui.io/docs/components/base/alert
 */
function CodeExportSheet({
  open,
  onClose,
  title,
  description,
  formats,
  initialFormatId,
  onLiveFetch,
  liveBusy,
  liveLabel = "С роутера",
  className,
  beforeCode,
  returnFocus,
}: CodeExportSheetProps) {
  const firstId = formats[0]?.id ?? "default"
  const initialTab = initialFormatId && formats.some(format => format.id === initialFormatId) ? initialFormatId : firstId
  const resetKey = JSON.stringify([open, initialTab])
  const [previousKey, setPreviousKey] = useState(resetKey)
  const [tab, setTab] = useState(initialTab)
  const [copiedCode, setCopiedCode] = useState<string | null>(null)
  if (previousKey !== resetKey) {
    setPreviousKey(resetKey)
    if (open) { setTab(initialTab); setCopiedCode(null) }
  }

  const active = useMemo(
    () => formats.find((f) => f.id === tab) ?? formats[0],
    [formats, tab],
  )

  const code = active?.code ?? ""
  const copied = !!code && copiedCode === code
  const emptyMessage = active?.emptyMessage
  const filename = active?.filename ?? "export.txt"
  const canCopy = Boolean(code) && !emptyMessage
  const isLive = Boolean(active?.isLive)
  const showTabs = formats.length > 1

  async function handleCopy() {
    if (!canCopy) return
    setCopiedCode(null)
    try {
      await navigator.clipboard.writeText(code)
      setCopiedCode(code)
      setTimeout(() => setCopiedCode(null), 1800)
    } catch { setCopiedCode(null); toast.error("Не удалось скопировать. Повторите действие или скачайте файл.") }
  }

  return (
    <Sheet open={open} onOpenChange={(v) => { if (!v) onClose() }}>
      <SheetContent finalFocus={returnFocus}
        className={cn(
          "flex w-full flex-col gap-0 overflow-hidden p-0 sm:max-w-xl",
          className,
        )}
      >
        <SheetHeader className="shrink-0 gap-1 border-b px-5 pt-5 pb-4 pr-12">
          <SheetTitle className="text-base font-semibold tracking-tight">
            {title}
          </SheetTitle>
          {description ? (
            <SheetDescription className="font-mono text-xs">
              {description}
            </SheetDescription>
          ) : null}
        </SheetHeader>

        <div className="flex min-h-0 flex-1 flex-col gap-3 px-5 py-4">
          {showTabs ? (
            <Tabs
              value={tab}
              onValueChange={(v) => setTab(String(v))}
              className="shrink-0 gap-0"
            >
              <TabsList className="h-9 w-full">
                {formats.map((f) => (
                  <TabsTrigger key={f.id} value={f.id} className="flex-1 px-2 text-xs sm:text-sm">
                    {f.label}
                  </TabsTrigger>
                ))}
              </TabsList>
            </Tabs>
          ) : null}

          {onLiveFetch || beforeCode ? (
            <div className="flex shrink-0 flex-wrap items-center justify-between gap-2">
              <div className="flex min-w-0 flex-wrap items-center gap-2">
                {onLiveFetch ? (
                  <Badge
                    variant={isLive ? "success-light" : "secondary"}
                    size="sm"
                    radius="full"
                  >
                    {isLive ? "С роутера" : "Локально"}
                  </Badge>
                ) : null}
                {beforeCode}
              </div>
              {onLiveFetch ? (
                <Button
                  type="button"
                  variant="outline"
                  size="sm"
                  className="shrink-0"
                  disabled={liveBusy}
                  onClick={() => onLiveFetch(tab)}
                  aria-label="Подтянуть конфиг с роутера с private-key"
                >
                  {liveBusy ? (
                    <LoaderCircleIcon className="size-3.5 animate-spin" />
                  ) : (
                    <RefreshCwIcon className="size-3.5" />
                  )}
                  {liveBusy ? "Загрузка…" : liveLabel}
                </Button>
              ) : null}
            </div>
          ) : null}

          <Frame dense className="flex min-h-0 flex-1 flex-col">
            <FramePanel className="relative flex min-h-0 flex-1 flex-col overflow-hidden p-0">
              {emptyMessage ? (
                <div className="flex flex-1 items-center p-4">
                  <Alert variant="warning" className="w-full">
                    <TriangleAlertIcon />
                    <AlertTitle>Нет данных</AlertTitle>
                    <AlertDescription>{emptyMessage}</AlertDescription>
                  </Alert>
                </div>
              ) : (
                <ScrollArea className="h-full min-h-0 flex-1">
                  <div className="min-h-[min(52vh,22rem)]">
                    <CodeBlock code={code} />
                  </div>
                </ScrollArea>
              )}
            </FramePanel>
          </Frame>

          {onLiveFetch && !isLive ? (
            <p className="text-muted-foreground shrink-0 text-[11px] leading-snug">
              Локальный снимок. Подтяните с роутера, если нужен private-key с устройства.
            </p>
          ) : null}
        </div>

        <SheetFooter className="shrink-0 flex-row items-center justify-between gap-3 border-t px-5 py-3.5 sm:flex-row">
          <SheetClose
            render={
              <Button type="button" variant="ghost" className="shrink-0 px-3" />
            }
          >
            Закрыть
          </SheetClose>
          <div className="flex items-center gap-2">
            <Button
              type="button"
              variant="outline"
              size="default"
              disabled={!canCopy}
              onClick={() => downloadText(filename, code)}
            >
              <DownloadIcon className="size-4" />
              Файл
            </Button>
            <Button
              type="button"
              size="default"
              disabled={!canCopy}
              onClick={handleCopy}
              className="min-w-28"
            >
              {copied ? (
                <CheckIcon className="size-4 text-success" />
              ) : (
                <CopyIcon className="size-4" />
              )}
              {copied ? "Скопировано" : "Копировать"}
            </Button>
          </div>
        </SheetFooter>
      </SheetContent>
    </Sheet>
  )
}

export { CodeExportSheet, CodeBlock, downloadText }