"use client";

import { useCallback, useEffect, useState } from "react";
import {
  ExternalLink,
  Loader2,
  MessageSquare,
  RefreshCw,
  Send,
  Sparkles,
} from "lucide-react";
import { Badge } from "@/components/ui/badge";
import { Button } from "@/components/ui/button";
import { Card, CardContent, CardHeader, CardTitle, CardDescription } from "@/components/ui/card";
import { EmptyState } from "@/components/layout/empty-state";
import { PageHeader } from "@/components/layout/page-header";
import { InlineAlert } from "@/components/ui/inline-alert";
import { Textarea } from "@/components/ui/textarea";
import { notify } from "@/lib/notifications/store";
import { useCapabilities } from "@/lib/capabilities/context";
import { useActionFeedback } from "@/lib/use-action-feedback";
import { THREADS_MAX_CHARS } from "@/lib/utils";

interface ReplyDraft {
  id: string;
  text: string;
  rationale?: string | null;
  status: string;
  publishedAt?: string | null;
  createdAt: string;
}

interface InboundReply {
  id: string;
  text: string;
  authorName?: string | null;
  permalink?: string | null;
  postedAt?: string | null;
  likeCount?: number | null;
  sentiment?: string | null;
  intent?: string | null;
  status: string;
  createdAt: string;
  published: {
    id: string;
    text: string;
    permalink?: string | null;
    publishedAt?: string | null;
  } | null;
  replyDrafts: ReplyDraft[];
}

const statusLabels: Record<string, { label: string; variant: "warning" | "secondary" | "success" }> = {
  NEW: { label: "待處理", variant: "warning" },
  DRAFTED: { label: "已生成草稿", variant: "secondary" },
  REPLIED: { label: "已回覆", variant: "success" },
};

const sentimentLabels: Record<string, string> = {
  positive: "正面",
  neutral: "中性",
  negative: "負面",
  question: "提問",
  lead: "潛在客戶",
};

export default function EngagementPage() {
  const [replies, setReplies] = useState<InboundReply[]>([]);
  const [loading, setLoading] = useState(true);
  const [busy, setBusy] = useState<string | null>(null);
  const [draftTexts, setDraftTexts] = useState<Record<string, string>>({});
  const { feedback, clearFeedback, showError, showSuccess } = useActionFeedback();
  const { isReady } = useCapabilities();
  const threadsApiReady = isReady("threadsApi");
  const aiReady = isReady("ai");

  const load = useCallback(async (silent = false) => {
    if (!silent) setLoading(true);
    try {
      const res = await fetch("/api/engagement/replies");
      const data = await res.json().catch(() => ({}));
      if (!res.ok) {
        showError(data.error ?? "無法載入留言", "載入失敗");
        setReplies([]);
        return;
      }
      setReplies(data.replies ?? []);
      setDraftTexts(
        Object.fromEntries(
          (data.replies ?? []).flatMap((reply: InboundReply) =>
            reply.replyDrafts.map((draft) => [draft.id, draft.text])
          )
        )
      );
    } catch {
      showError("網路連線異常，請稍後再試", "載入失敗");
      setReplies([]);
    } finally {
      if (!silent) setLoading(false);
    }
  }, [showError]);

  useEffect(() => {
    load();
  }, [load]);

  async function syncReplies() {
    setBusy("sync");
    try {
      const res = await fetch("/api/engagement/replies", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ sync: true }),
      });
      const data = await res.json().catch(() => ({}));
      if (!res.ok) {
        showError(data.error ?? "同步失敗", "同步留言失敗");
        return;
      }
      showSuccess("已從 Threads 同步留言");
      load(true);
    } catch {
      showError("網路連線異常，請稍後再試", "同步留言失敗");
    } finally {
      setBusy(null);
    }
  }

  async function generateDraft(replyId: string) {
    setBusy(`gen-${replyId}`);
    try {
      const res = await fetch(`/api/engagement/replies/${replyId}/generate`, {
        method: "POST",
      });
      const data = await res.json().catch(() => ({}));
      if (!res.ok) {
        notify({ type: "error", title: "生成回覆失敗", message: data.error });
        return;
      }
      notify({ type: "success", title: "已生成回覆草稿" });
      load(true);
    } catch {
      notify({ type: "error", title: "生成回覆失敗", message: "網路連線異常，請稍後再試" });
    } finally {
      setBusy(null);
    }
  }

  async function saveDraft(draftId: string) {
    setBusy(`save-${draftId}`);
    try {
      const res = await fetch(`/api/engagement/reply-drafts/${draftId}`, {
        method: "PATCH",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ text: draftTexts[draftId], status: "EDITED" }),
      });
      const data = await res.json().catch(() => ({}));
      if (!res.ok) {
        showError(data.error ?? "無法儲存草稿", "儲存失敗");
        return;
      }
      showSuccess("草稿已儲存");
      load(true);
    } catch {
      showError("網路連線異常，請稍後再試", "儲存失敗");
    } finally {
      setBusy(null);
    }
  }

  async function publishDraft(draftId: string) {
    setBusy(`publish-${draftId}`);
    try {
      const res = await fetch(`/api/engagement/reply-drafts/${draftId}/publish`, {
        method: "POST",
      });
      const data = await res.json().catch(() => ({}));
      if (!res.ok) {
        notify({ type: "error", title: "發布回覆失敗", message: data.error });
        return;
      }
      notify({ type: "success", title: "回覆已發布到 Threads" });
      load(true);
    } catch {
      notify({ type: "error", title: "發布回覆失敗", message: "網路連線異常，請稍後再試" });
    } finally {
      setBusy(null);
    }
  }

  async function copyText(text: string) {
    try {
      await navigator.clipboard.writeText(text);
      showSuccess("已複製回覆");
    } catch {
      showError("無法複製，請手動選取文字", "複製失敗");
    }
  }

  const pendingCount = replies.filter((r) => r.status === "NEW").length;

  return (
    <div>
      <PageHeader
        eyebrow="03 / ENGAGEMENT"
        title="互動經營"
        description="同步 Threads 貼文底下的留言，用 AI 分析情緒並生成回覆草稿，再一鍵發布回覆。"
        action={
          <Button
            size="lg"
            onClick={syncReplies}
            disabled={busy === "sync" || !threadsApiReady}
            title={!threadsApiReady ? "需先在連線設定綁定 Threads API" : undefined}
          >
            {busy === "sync" ? <Loader2 className="h-4 w-4 animate-spin" /> : <RefreshCw className="h-4 w-4" />}
            同步留言
          </Button>
        }
      />

      {feedback && (
        <InlineAlert
          type={feedback.type}
          title={feedback.title}
          message={feedback.message}
          onDismiss={clearFeedback}
          className="mb-4"
        />
      )}

      {!threadsApiReady && (
        <InlineAlert
          type="info"
          title="Threads API 尚未連線"
          message="同步留言與發布回覆需要 Threads 官方 API。可先綁定後再使用，或手動複製回覆至 Threads。"
          className="mb-4"
        />
      )}

      {loading ? (
        <div className="space-y-4">
          {[0, 1, 2].map((i) => (
            <div key={i} className="skeleton h-56 animate-pulse" />
          ))}
        </div>
      ) : replies.length === 0 ? (
        <EmptyState
          icon={MessageSquare}
          title="尚無留言紀錄"
          description={
            threadsApiReady
              ? "點上方「同步留言」從 Threads 拉取最新留言。"
              : "請先到連線設定綁定 Threads API，再同步留言。"
          }
          action={
            threadsApiReady ? (
              <Button onClick={syncReplies} disabled={busy === "sync"}>
                {busy === "sync" ? <Loader2 className="h-4 w-4 animate-spin" /> : <RefreshCw className="h-4 w-4" />}
                立即同步
              </Button>
            ) : (
              <Button asChild variant="outline">
                <a href="/connections">前往連線設定</a>
              </Button>
            )
          }
        />
      ) : (
        <div className="space-y-4">
          {pendingCount > 0 && (
            <div className="flex items-center gap-2 text-sm text-muted-foreground">
              <Badge variant="warning">{pendingCount} 則待處理</Badge>
            </div>
          )}

          {replies.map((reply) => {
            const statusInfo = statusLabels[reply.status] ?? {
              label: reply.status,
              variant: "secondary" as const,
            };
            return (
              <Card key={reply.id}>
                <CardHeader>
                  <div className="flex flex-col gap-3 sm:flex-row sm:items-start sm:justify-between">
                    <div className="min-w-0">
                      <CardTitle className="flex flex-wrap items-center gap-2">
                        @{reply.authorName ?? "匿名"}
                        <Badge variant={statusInfo.variant}>{statusInfo.label}</Badge>
                        {reply.sentiment && (
                          <Badge variant="outline">
                            {sentimentLabels[reply.sentiment] ?? reply.sentiment}
                          </Badge>
                        )}
                      </CardTitle>
                      <CardDescription>
                        {reply.postedAt
                          ? new Date(reply.postedAt).toLocaleDateString("zh-TW", {
                              month: "short",
                              day: "numeric",
                              hour: "2-digit",
                              minute: "2-digit",
                            })
                          : ""}
                        {reply.likeCount != null && ` · ${reply.likeCount} 讚`}
                      </CardDescription>
                    </div>
                    <div className="flex flex-wrap gap-2">
                      {reply.status === "NEW" && (
                        <Button
                          size="sm"
                          variant="outline"
                          onClick={() => generateDraft(reply.id)}
                          disabled={busy === `gen-${reply.id}` || !aiReady}
                          title={!aiReady ? "需先設定 AI API Key" : undefined}
                        >
                          {busy === `gen-${reply.id}` ? (
                            <Loader2 className="h-3.5 w-3.5 animate-spin" />
                          ) : (
                            <Sparkles className="h-3.5 w-3.5" />
                          )}
                          生成回覆
                        </Button>
                      )}
                      {reply.permalink && (
                        <Button size="sm" variant="outline" asChild>
                          <a href={reply.permalink} target="_blank" rel="noreferrer">
                            <ExternalLink className="h-3.5 w-3.5" />
                            原留言
                          </a>
                        </Button>
                      )}
                    </div>
                  </div>
                </CardHeader>
                <CardContent className="space-y-4">
                  <div className="rounded-lg border border-border bg-muted/50 p-3">
                    <p className="text-[13px] leading-relaxed">{reply.text}</p>
                    {reply.intent && (
                      <p className="mt-2 text-xs text-muted-foreground">意圖分析：{reply.intent}</p>
                    )}
                  </div>

                  {reply.published && (
                    <div className="rounded-lg border border-dashed border-border p-3">
                      <p className="mb-1 text-[11px] font-medium uppercase tracking-wide text-muted-foreground">
                        你的貼文
                      </p>
                      <p className="line-clamp-2 text-[13px] leading-relaxed text-muted-foreground">
                        {reply.published.text}
                      </p>
                      {reply.published.permalink && (
                        <a
                          href={reply.published.permalink}
                          target="_blank"
                          rel="noreferrer"
                          className="mt-1 inline-flex items-center gap-1 text-[11px] text-primary hover:underline"
                        >
                          <ExternalLink className="h-3 w-3" />
                          查看貼文
                        </a>
                      )}
                    </div>
                  )}

                  {reply.replyDrafts.map((draft) => {
                    const value = draftTexts[draft.id] ?? draft.text;
                    const isPublished = draft.status === "PUBLISHED";
                    return (
                      <div key={draft.id} className="space-y-2 rounded-lg border border-border p-3">
                        <div className="flex items-center justify-between gap-2">
                          <div className="flex flex-wrap gap-1.5">
                            <Badge variant={isPublished ? "success" : "warning"}>
                              {isPublished ? "已發布" : "待發布"}
                            </Badge>
                          </div>
                          <span className="font-mono text-xs text-muted-foreground">
                            {value.length}/{THREADS_MAX_CHARS}
                          </span>
                        </div>
                        <Textarea
                          value={value}
                          rows={3}
                          onChange={(e) =>
                            setDraftTexts((prev) => ({ ...prev, [draft.id]: e.target.value }))
                          }
                        />
                        {draft.rationale && (
                          <p className="text-xs text-muted-foreground">{draft.rationale}</p>
                        )}
                        <div className="flex flex-wrap gap-2">
                          {!isPublished && (
                            <>
                              <Button
                                size="sm"
                                variant="outline"
                                onClick={() => saveDraft(draft.id)}
                                disabled={busy === `save-${draft.id}`}
                              >
                                儲存
                              </Button>
                              <Button
                                size="sm"
                                variant="outline"
                                onClick={() => copyText(value)}
                              >
                                複製
                              </Button>
                              <Button
                                size="sm"
                                onClick={() => publishDraft(draft.id)}
                                disabled={
                                  busy === `publish-${draft.id}` || !threadsApiReady
                                }
                                title={
                                  !threadsApiReady
                                    ? "需先在連線設定綁定 Threads API"
                                    : undefined
                                }
                              >
                                {busy === `publish-${draft.id}` ? (
                                  <Loader2 className="h-3.5 w-3.5 animate-spin" />
                                ) : (
                                  <Send className="h-3.5 w-3.5" />
                                )}
                                發布回覆
                              </Button>
                            </>
                          )}
                        </div>
                      </div>
                    );
                  })}
                </CardContent>
              </Card>
            );
          })}
        </div>
      )}
    </div>
  );
}