"use client";

import {
  CheckIcon,
  CopyIcon,
  DownloadIcon,
  ExternalLinkIcon,
  Loader2,
  Trash2Icon,
} from "lucide-react";
import { useEffect, useState } from "react";
import { toast } from "sonner";

import { Button } from "@/components/ui/button";
import {
  Dialog,
  DialogContent,
  DialogDescription,
  DialogHeader,
  DialogTitle,
} from "@/components/ui/dialog";
import { Input } from "@/components/ui/input";
import { useI18n } from "@/core/i18n/hooks";
import type {
  SharePreview,
  ThreadShare,
  ThreadShareMode,
} from "@/core/thread-shares/api";
import { buildPublicShareUrl, extractShareCode } from "@/core/thread-shares/api";
import {
  useCreateShare,
  useImportShare,
  usePreviewShare,
  useRevokeShare,
} from "@/core/thread-shares/hooks";
import { cn } from "@/lib/utils";

function errorMessage(err: unknown): string {
  return err instanceof Error ? err.message : String(err);
}

/**
 * Dialog that produces a share link for a single conversation. Two modes:
 *
 * - `import` — mints a short code; a recipient enters it in the import dialog
 *   to copy the conversation into their own account.
 * - `view` — mints a public, read-only link that anyone can open without
 *   logging in (a static page; viewers cannot send new messages).
 */
export function ShareConversationDialog({
  threadId,
  open,
  onOpenChange,
}: {
  threadId: string | null;
  open: boolean;
  onOpenChange: (open: boolean) => void;
}) {
  const { t } = useI18n();
  const tx = t.threadShare;
  const createShare = useCreateShare();
  const revokeShare = useRevokeShare();
  const [mode, setMode] = useState<ThreadShareMode>("view");
  const [share, setShare] = useState<ThreadShare | null>(null);
  const [copied, setCopied] = useState(false);

  // Reset to the default mode (read-only link) every time the dialog opens.
  useEffect(() => {
    if (open) setMode("view");
  }, [open, threadId]);

  // Mint / reuse the link whenever the dialog opens or the mode changes.
  useEffect(() => {
    if (!open || !threadId) return;
    setShare(null);
    setCopied(false);
    createShare
      .mutateAsync({ threadId, mode })
      .then(setShare)
      .catch((err) => toast.error(errorMessage(err)));
    // createShare is stable enough; re-running only on open/threadId/mode is intended.
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [open, threadId, mode]);

  const isView = mode === "view";
  const publicUrl =
    isView && share ? buildPublicShareUrl(share.share_code) : "";

  async function handleCopy() {
    if (!share) return;
    const text = isView ? publicUrl : share.share_code;
    try {
      await navigator.clipboard.writeText(text);
      setCopied(true);
      toast.success(isView ? "链接已复制" : tx.codeCopied);
      setTimeout(() => setCopied(false), 1500);
    } catch {
      toast.error(t.clipboard.failedToCopyToClipboard);
    }
  }

  async function handleRevoke() {
    if (!share || !window.confirm(tx.revokeConfirm)) return;
    try {
      await revokeShare.mutateAsync(share.share_code);
      toast.success(tx.revokeSuccess);
      onOpenChange(false);
    } catch (err) {
      toast.error(errorMessage(err));
    }
  }

  return (
    <Dialog open={open} onOpenChange={onOpenChange}>
      <DialogContent className="sm:max-w-md">
        <DialogHeader>
          <DialogTitle>{tx.shareTitle}</DialogTitle>
          <DialogDescription>
            {isView
              ? "生成一个只读链接，任何人无需登录都能查看这个对话，但不能继续提问。"
              : tx.shareDescription}
          </DialogDescription>
        </DialogHeader>

        {/* Mode selector */}
        <div className="bg-muted flex gap-1 rounded-lg p-1">
          {(
            [
              { value: "view" as const, label: "只读链接" },
              { value: "import" as const, label: "导入副本" },
            ]
          ).map((option) => (
            <button
              key={option.value}
              type="button"
              onClick={() => setMode(option.value)}
              className={cn(
                "flex-1 rounded-md px-3 py-1.5 text-sm transition-colors",
                mode === option.value
                  ? "bg-background text-foreground shadow-sm"
                  : "text-muted-foreground hover:text-foreground",
              )}
            >
              {option.label}
            </button>
          ))}
        </div>

        {!share ? (
          <div className="text-muted-foreground flex items-center gap-2 py-8 text-sm">
            <Loader2 className="size-4 animate-spin" />
            {tx.generating}
          </div>
        ) : (
          <div className="space-y-3">
            <div>
              <p className="text-muted-foreground mb-1 text-xs">
                {isView ? "只读链接" : tx.shareCodeLabel}
              </p>
              <div className="flex items-center gap-2">
                {isView ? (
                  <Input
                    readOnly
                    value={publicUrl}
                    onFocus={(e) => e.currentTarget.select()}
                    className="flex-1 font-mono text-xs"
                  />
                ) : (
                  <code className="bg-muted flex-1 rounded-md px-3 py-2 text-center font-mono text-lg tracking-[0.3em]">
                    {share.share_code}
                  </code>
                )}
                <Button variant="outline" onClick={() => void handleCopy()}>
                  {copied ? (
                    <CheckIcon className="size-4" />
                  ) : (
                    <CopyIcon className="size-4" />
                  )}
                  {isView ? "复制链接" : tx.copyCode}
                </Button>
              </div>
            </div>
            {isView ? (
              <div className="space-y-3">
                <p className="text-muted-foreground text-xs">
                  拿到链接的人都能查看这个对话的全部内容（只读），无法继续发送问题。撤销后链接立即失效。
                </p>
                <Button
                  variant="outline"
                  size="sm"
                  onClick={() => window.open(publicUrl, "_blank", "noopener")}
                >
                  <ExternalLinkIcon className="size-3.5" />
                  在新标签页打开
                </Button>
              </div>
            ) : (
              <p className="text-muted-foreground text-xs">{tx.shareHint}</p>
            )}
            <Button
              variant="ghost"
              size="sm"
              className="text-destructive hover:text-destructive"
              disabled={revokeShare.isPending}
              onClick={() => void handleRevoke()}
            >
              <Trash2Icon className="size-3.5" />
              {tx.revoke}
            </Button>
          </div>
        )}
      </DialogContent>
    </Dialog>
  );
}

/** Dialog where a user pastes a share code to import someone's conversation. */
export function ImportConversationsDialog({
  open,
  onOpenChange,
}: {
  open: boolean;
  onOpenChange: (open: boolean) => void;
}) {
  const { t } = useI18n();
  const tx = t.threadShare;
  const [input, setInput] = useState("");
  const [preview, setPreview] = useState<SharePreview | null>(null);
  const previewShare = usePreviewShare();
  const importShare = useImportShare();

  // Reset state whenever the dialog closes.
  useEffect(() => {
    if (!open) {
      setInput("");
      setPreview(null);
    }
  }, [open]);

  async function handlePreview() {
    const code = extractShareCode(input);
    if (!code) {
      toast.error(tx.emptyCode);
      return;
    }
    try {
      setPreview(await previewShare.mutateAsync(code));
    } catch (err) {
      setPreview(null);
      toast.error(errorMessage(err));
    }
  }

  async function handleImport() {
    const code = preview?.share_code ?? extractShareCode(input);
    if (!code) {
      toast.error(tx.emptyCode);
      return;
    }
    try {
      const result = await importShare.mutateAsync(code);
      if (result.imported > 0) {
        toast.success(tx.importSuccess);
      } else {
        toast.info(tx.alreadyImported);
      }
      onOpenChange(false);
    } catch (err) {
      toast.error(errorMessage(err));
    }
  }

  return (
    <Dialog open={open} onOpenChange={onOpenChange}>
      <DialogContent className="sm:max-w-md">
        <DialogHeader>
          <DialogTitle>{tx.importTitle}</DialogTitle>
          <DialogDescription>{tx.importDescription}</DialogDescription>
        </DialogHeader>

        <div className="flex gap-2">
          <Input
            value={input}
            onChange={(e) => {
              setInput(e.target.value);
              setPreview(null);
            }}
            placeholder={tx.codeInputPlaceholder}
            className="font-mono"
          />
          <Button
            variant="outline"
            onClick={() => void handlePreview()}
            disabled={previewShare.isPending || !input.trim()}
          >
            {previewShare.isPending && (
              <Loader2 className="size-4 animate-spin" />
            )}
            {tx.preview}
          </Button>
        </div>

        {preview && (
          <div className="space-y-2 rounded-lg border p-3 text-sm">
            <p className="font-medium">
              {tx.previewConversation.replace("{title}", preview.title)}
            </p>
            <p className="text-muted-foreground text-xs">
              {tx.previewFrom.replace("{user}", preview.shared_by)}
            </p>
            <Button
              className="w-full"
              onClick={() => void handleImport()}
              disabled={importShare.isPending}
            >
              {importShare.isPending ? (
                <Loader2 className="size-4 animate-spin" />
              ) : (
                <DownloadIcon className="size-4" />
              )}
              {importShare.isPending ? tx.importing : tx.doImport}
            </Button>
          </div>
        )}
      </DialogContent>
    </Dialog>
  );
}