"use client";

import { useState } from "react";
import { toast } from "sonner";

import { Button } from "@/components/ui/button";
import { Textarea } from "@/components/ui/textarea";
import { getBackendBaseURL } from "@/core/config";
import { useI18n } from "@/core/i18n/hooks";

type ThreadMemoryPanelProps = {
  threadId?: string;
};

export function ThreadMemoryPanel({ threadId }: ThreadMemoryPanelProps) {
  const [memorySummary, setMemorySummary] = useState("");
  const [memoryVersion, setMemoryVersion] = useState<number | null>(null);
  const [loadingSummary, setLoadingSummary] = useState(false);
  const [savingSummary, setSavingSummary] = useState(false);
  const [deletingMemory, setDeletingMemory] = useState(false);
  const { t } = useI18n();
  if (!threadId || threadId === "new") return null;

  const handleLoadMemorySummary = async () => {
    setLoadingSummary(true);
    try {
      const res = await fetch(
        `${getBackendBaseURL()}/api/threads/${encodeURIComponent(threadId)}/memory-summary`,
      );
      if (!res.ok) throw new Error(`HTTP ${res.status}`);
      const data = (await res.json()) as { summary: string; memoryVersion: number };
      setMemorySummary(data.summary ?? "");
      setMemoryVersion(data.memoryVersion ?? 0);
      toast.success(t.threadMemoryPanel.toastLoadSuccess);
    } catch {
      toast.error(t.threadMemoryPanel.toastLoadFailed);
    } finally {
      setLoadingSummary(false);
    }
  };

  const handleSaveMemorySummary = async () => {
    if (memoryVersion == null) return;
    setSavingSummary(true);
    try {
      const res = await fetch(
        `${getBackendBaseURL()}/api/threads/${encodeURIComponent(threadId)}/memory-summary`,
        {
          method: "POST",
          headers: { "Content-Type": "application/json" },
          body: JSON.stringify({ summary: memorySummary, memoryVersion }),
        },
      );
      if (res.status === 409) {
        toast.error(t.threadMemoryPanel.toastConflict);
        return;
      }
      if (!res.ok) throw new Error(`HTTP ${res.status}`);
      const data = (await res.json()) as { memoryVersion?: number };
      if (typeof data.memoryVersion === "number") setMemoryVersion(data.memoryVersion);
      toast.success(t.threadMemoryPanel.toastSaveSuccess);
    } catch {
      toast.error(t.threadMemoryPanel.toastSaveFailed);
    } finally {
      setSavingSummary(false);
    }
  };

  const handleDeleteMemory = async () => {
    setDeletingMemory(true);
    try {
      const res = await fetch(
        `${getBackendBaseURL()}/api/threads/${encodeURIComponent(threadId)}/memory`,
        { method: "DELETE" },
      );
      if (!res.ok) throw new Error(`HTTP ${res.status}`);
      setMemorySummary("");
      setMemoryVersion(0);
      toast.success(t.threadMemoryPanel.toastDeleteSuccess);
    } catch {
      toast.error(t.threadMemoryPanel.toastDeleteFailed);
    } finally {
      setDeletingMemory(false);
    }
  };

  return (
    <div className="w-[380px] space-y-2 rounded-lg border border-ws-divider bg-ws-surface-elevated p-3 shadow-lg">
      <div className="text-sm font-semibold">
        <span className="hidden sm:inline">{t.threadMemoryPanel.title}</span>
      </div>
      <div className="space-y-2">
        <div className="flex items-center gap-2">
          <Button
            size="sm"
            variant="outline"
            onClick={() => {
              void handleLoadMemorySummary();
            }}
            disabled={loadingSummary}
          >
            {loadingSummary ? t.threadMemoryPanel.loading : t.threadMemoryPanel.load}
          </Button>
          <Button
            size="sm"
            onClick={() => {
              void handleSaveMemorySummary();
            }}
            disabled={savingSummary || memoryVersion == null}
          >
            {savingSummary ? t.threadMemoryPanel.saving : t.threadMemoryPanel.save}
          </Button>
          <Button
            size="sm"
            variant="destructive"
            onClick={() => {
              void handleDeleteMemory();
            }}
            disabled={deletingMemory}
          >
            {deletingMemory ? t.threadMemoryPanel.removing : t.threadMemoryPanel.remove}
          </Button>
        </div>
        <div className="text-xs text-ws-text-subtle-strong">
          {t.threadMemoryPanel.threadId}: {threadId.slice(0, 8)}... |{" "}
          {t.threadMemoryPanel.version}:{" "}
          {memoryVersion == null ? t.threadMemoryPanel.unavailableVersion : memoryVersion}
        </div>
        <Textarea
          value={memorySummary}
          onChange={(e) => setMemorySummary(e.target.value)}
          placeholder={t.threadMemoryPanel.summaryPlaceholder}
          className="min-h-32 bg-white/80"
        />
      </div>
    </div>
  );
}
