"use client"

import {
  ActionBarPrimitive,
  BranchPickerPrimitive,
  ComposerPrimitive,
  MessagePrimitive,
  ThreadPrimitive,
  ThreadListItemPrimitive,
  ThreadListPrimitive,
  useMessage,
} from "@assistant-ui/react";
import type { FC } from "react";
import {
  ArrowDownIcon,
  CheckIcon,
  ChevronLeftIcon,
  ChevronRightIcon,
  CopyIcon,
  PencilIcon,
  RefreshCwIcon,
  SendHorizontalIcon,
  ArchiveIcon,
  PlusIcon,
} from "lucide-react";
import { cn } from "@/lib/utils";
import { Dispatch, SetStateAction, useState } from "react";
import { Button } from "@/components/ui/button";
import { ScrollArea } from "../ui/scroll-area";
import { TooltipIconButton } from "@/components/assistant-ui/tooltip-icon-button";
import { MemoryUI } from "./memory-ui";
import MarkdownRenderer from "../mem0/markdown";
import React from "react";
import {
  AlertDialog,
  AlertDialogAction,
  AlertDialogCancel,
  AlertDialogContent,
  AlertDialogDescription,
  AlertDialogFooter,
  AlertDialogHeader,
  AlertDialogTitle,
  AlertDialogTrigger,
} from "@/components/ui/alert-dialog";

interface ThreadProps {
  sidebarOpen: boolean;
  setSidebarOpen: Dispatch<SetStateAction<boolean>>;
  onResetUserId?: () => void;
}

export const Thread: FC<ThreadProps> = ({ sidebarOpen, setSidebarOpen, onResetUserId }) => {
  const [resetDialogOpen, setResetDialogOpen] = useState(false);

  return (
    <ThreadPrimitive.Root
      className="bg-[#f8fafc] dark:bg-zinc-900 box-border h-full flex flex-col overflow-hidden relative"
      style={{
        ["--thread-max-width" as string]: "42rem",
      }}
    >
      {/* Mobile sidebar overlay */}
      {sidebarOpen && (
        <div 
          className="fixed inset-0 bg-black/40 z-30 md:hidden"
          onClick={() => setSidebarOpen(false)}
        ></div>
      )}

      {/* Mobile sidebar drawer */}
      <div className={cn(
        "fixed inset-y-0 left-0 z-40 w-[85%] bg-white dark:bg-zinc-900 transform transition-transform duration-300 ease-in-out md:hidden",
        sidebarOpen ? "translate-x-0" : "-translate-x-full"
      )}>
        <div className="h-full flex flex-col">
          <div className="flex items-center justify-between border-b dark:text-white border-[#e2e8f0] dark:border-zinc-800 p-4">
            <h2 className="font-medium">Recent Chats</h2>
            <div className="flex items-center gap-2">
              {onResetUserId && (
                <AlertDialog open={resetDialogOpen} onOpenChange={setResetDialogOpen}>
                  <AlertDialogTrigger asChild>
                    <TooltipIconButton
                      tooltip="Reset Memory"
                      className="hover:text-[#4f46e5] text-[#475569] dark:text-zinc-300 dark:hover:text-[#6366f1] size-8 p-0"
                      variant="ghost"
                    >
                      <RefreshCwIcon className="w-4 h-4" />
                    </TooltipIconButton>
                  </AlertDialogTrigger>
                  <AlertDialogContent className="bg-white dark:bg-zinc-900 border-[#e2e8f0] dark:border-zinc-800">
                    <AlertDialogHeader>
                      <AlertDialogTitle className="text-[#1e293b] dark:text-white">Reset Memory</AlertDialogTitle>
                      <AlertDialogDescription className="text-[#475569] dark:text-zinc-300">
                        This will permanently delete all your chat history and memories. This action cannot be undone.
                      </AlertDialogDescription>
                    </AlertDialogHeader>
                    <AlertDialogFooter>
                      <AlertDialogCancel className="text-[#475569] dark:text-zinc-300 hover:bg-[#eef2ff] dark:hover:bg-zinc-800">Cancel</AlertDialogCancel>
                      <AlertDialogAction
                        onClick={() => {
                          onResetUserId();
                          setResetDialogOpen(false);
                        }}
                        className="bg-[#4f46e5] hover:bg-[#4338ca] dark:bg-[#6366f1] dark:hover:bg-[#4f46e5] text-white"
                      >
                        Reset
                      </AlertDialogAction>
                    </AlertDialogFooter>
                  </AlertDialogContent>
                </AlertDialog>
              )}
              <Button 
                variant="ghost" 
                size="sm" 
                onClick={() => setSidebarOpen(false)}
                className="text-[#475569] dark:text-zinc-300 hover:bg-[#eef2ff] dark:hover:bg-zinc-800 h-8 w-8 p-0"
              >
                ✕
              </Button>
            </div>
          </div>
          <div className="flex-1 overflow-y-auto p-3">
            <ThreadListPrimitive.Root className="flex flex-col items-stretch gap-1.5 h-full dark:text-white">
              <ThreadListPrimitive.New asChild>
                <Button
                  className="hover:bg-[#eef2ff] dark:hover:bg-zinc-800 dark:data-[active]:bg-zinc-800 flex items-center justify-start gap-1 rounded-lg px-2.5 py-2 text-start bg-[#4f46e5] text-white dark:bg-[#6366f1]"
                  variant="default"
                >
                  <PlusIcon className="w-4 h-4" />
                  New Thread
                </Button>
              </ThreadListPrimitive.New>
              <div className="mt-4 mb-2">
                <h2 className="text-sm font-medium text-[#475569] dark:text-zinc-300 px-2.5">Recent Chats</h2>
              </div>
              <ThreadListPrimitive.Items components={{ ThreadListItem }} />
            </ThreadListPrimitive.Root>
          </div>
        </div>
      </div>

      <ScrollArea className="flex-1">
        <div className="flex h-full flex-col items-center px-4 pt-8 justify-end">
          <ThreadWelcome />

          <ThreadPrimitive.Messages
            components={{
              UserMessage: UserMessage,
              EditComposer: EditComposer,
              AssistantMessage: AssistantMessage,
            }}
          />

          <ThreadPrimitive.If empty={false}>
            <div className="min-h-8 flex-grow" />
          </ThreadPrimitive.If>
        </div>
      </ScrollArea>

      <div className="sticky bottom-0 mt-3 flex w-full max-w-[var(--thread-max-width)] flex-col items-center justify-end rounded-t-lg bg-inherit px-4 pb-4 mx-auto">
        <ThreadScrollToBottom />
        <Composer />
      </div>
    </ThreadPrimitive.Root>
  );
};

const ThreadScrollToBottom: FC = () => {
  return (
    <ThreadPrimitive.ScrollToBottom asChild>
      <TooltipIconButton
        tooltip="Scroll to bottom"
        variant="outline"
        className="absolute -top-8 rounded-full disabled:invisible bg-white dark:bg-zinc-800 border-[#e2e8f0] dark:border-zinc-700 hover:bg-[#eef2ff] dark:hover:bg-zinc-700"
      >
        <ArrowDownIcon className="text-[#475569] dark:text-zinc-300" />
      </TooltipIconButton>
    </ThreadPrimitive.ScrollToBottom>
  );
};

const ThreadWelcome: FC = () => {
  return (
    <ThreadPrimitive.Empty>
      <div className="flex w-full max-w-[var(--thread-max-width)] flex-grow flex-col">
        <div className="flex w-full flex-grow flex-col items-center justify-start h-[calc(100vh-23rem)] md:h-[calc(100vh-18rem)]">
          <div className="flex flex-col items-center justify-center h-full">
            <div className="text-5xl font-bold text-[#1e293b] dark:text-white mb-2">
              Mem0 Demo
            </div>
            <p className="text-center text-sm text-[#1e293b] dark:text-white mb-2 w-3/4">
            A personalized AI chat app powered by Mem0 that remembers your preferences, facts, and memories.
            </p>
          </div>
        </div>
        <div className="flex flex-col items-center justify-center">
        <p className="mt-4 font-medium text-[#1e293b] dark:text-white">
            How can I help you today?
          </p>
        <ThreadWelcomeSuggestions />
        </div>
      </div>
    </ThreadPrimitive.Empty>
  );
};

const ThreadWelcomeSuggestions: FC = () => {
  return (
    <div className="mt-3 flex w-full items-stretch justify-center gap-4 dark:text-white">
      <ThreadPrimitive.Suggestion
        className="hover:bg-[#eef2ff] dark:hover:bg-zinc-800 flex max-w-sm grow basis-0 flex-col items-center justify-center rounded-[2rem] border border-[#e2e8f0] dark:border-zinc-700 p-3 transition-colors ease-in"
        prompt="I like to travel to "
        method="replace"
      >
        <span className="line-clamp-2 text-ellipsis text-sm font-semibold">Travel</span>
      </ThreadPrimitive.Suggestion>
      <ThreadPrimitive.Suggestion
        className="hover:bg-[#eef2ff] dark:hover:bg-zinc-800 flex max-w-sm grow basis-0 flex-col items-center justify-center rounded-[2rem] border border-[#e2e8f0] dark:border-zinc-700 p-3 transition-colors ease-in"
        prompt="I like to eat "
        method="replace"
      >
        <span className="line-clamp-2 text-ellipsis text-sm font-semibold">Food</span>
      </ThreadPrimitive.Suggestion>
      <ThreadPrimitive.Suggestion
        className="hover:bg-[#eef2ff] dark:hover:bg-zinc-800 flex max-w-sm grow basis-0 flex-col items-center justify-center rounded-[2rem] border border-[#e2e8f0] dark:border-zinc-700 p-3 transition-colors ease-in"
        prompt="I am working on "
        method="replace"
      >
        <span className="line-clamp-2 text-ellipsis text-sm font-semibold">Project details</span>
      </ThreadPrimitive.Suggestion>
    </div>
  );
};

const Composer: FC = () => {
  return (
    <ComposerPrimitive.Root className="focus-within:border-[#4f46e5]/20 dark:focus-within:border-[#6366f1]/20 flex w-full flex-wrap items-end rounded-full border border-[#e2e8f0] dark:border-zinc-700 bg-white dark:bg-zinc-800 px-2.5 shadow-sm transition-colors ease-in">
      <ComposerPrimitive.Input
        rows={1}
        autoFocus
        placeholder="Message to Mem0..."
        className="placeholder:text-zinc-400 dark:placeholder:text-zinc-500 max-h-40 flex-grow resize-none border-none bg-transparent px-2 py-4 text-sm outline-none focus:ring-0 disabled:cursor-not-allowed text-[#1e293b] dark:text-zinc-200"
      />
      <ComposerAction />
    </ComposerPrimitive.Root>
  );
};

const ComposerAction: FC = () => {
  return (
    <>
      <ThreadPrimitive.If running={false}>
        <ComposerPrimitive.Send asChild>
          <TooltipIconButton
            tooltip="Send"
            variant="default"
            className="my-2.5 size-8 p-2 transition-opacity ease-in bg-[#4f46e5] dark:bg-[#6366f1] hover:bg-[#4338ca] dark:hover:bg-[#4f46e5] text-white rounded-full"
          >
            <SendHorizontalIcon />
          </TooltipIconButton>
        </ComposerPrimitive.Send>
      </ThreadPrimitive.If>
      <ThreadPrimitive.If running>
        <ComposerPrimitive.Cancel asChild>
          <TooltipIconButton
            tooltip="Cancel"
            variant="default"
            className="my-2.5 size-8 p-2 transition-opacity ease-in bg-[#4f46e5] dark:bg-[#6366f1] hover:bg-[#4338ca] dark:hover:bg-[#4f46e5] text-white rounded-full"
          >
            <CircleStopIcon />
          </TooltipIconButton>
        </ComposerPrimitive.Cancel>
      </ThreadPrimitive.If>
    </>
  );
};

const UserMessage: FC = () => {
  return (
    <MessagePrimitive.Root className="grid auto-rows-auto grid-cols-[minmax(72px,1fr)_auto] gap-y-2 [&:where(>*)]:col-start-2 w-full max-w-[var(--thread-max-width)] py-4">
      <UserActionBar />

      <div className="bg-[#4f46e5] text-sm dark:bg-[#6366f1] text-white max-w-[calc(var(--thread-max-width)*0.8)] break-words rounded-3xl px-5 py-2.5 col-start-2 row-start-2">
        <MessagePrimitive.Content />
      </div>

      <BranchPicker className="col-span-full col-start-1 row-start-3 -mr-1 justify-end" />
    </MessagePrimitive.Root>
  );
};

const UserActionBar: FC = () => {
  return (
    <ActionBarPrimitive.Root
      hideWhenRunning
      autohide="not-last"
      className="flex flex-col items-end col-start-1 row-start-2 mr-3 mt-2.5"
    >
      <ActionBarPrimitive.Edit asChild>
        <TooltipIconButton
          tooltip="Edit"
          className="text-[#475569] dark:text-zinc-300 hover:text-[#4f46e5] dark:hover:text-[#6366f1] hover:bg-[#eef2ff] dark:hover:bg-zinc-800"
        >
          <PencilIcon />
        </TooltipIconButton>
      </ActionBarPrimitive.Edit>
    </ActionBarPrimitive.Root>
  );
};

const EditComposer: FC = () => {
  return (
    <ComposerPrimitive.Root className="bg-[#eef2ff] dark:bg-zinc-800 my-4 flex w-full max-w-[var(--thread-max-width)] flex-col gap-2 rounded-xl">
      <ComposerPrimitive.Input className="text-[#1e293b] dark:text-zinc-200 flex h-8 w-full resize-none bg-transparent p-4 pb-0 outline-none" />

      <div className="mx-3 mb-3 flex items-center justify-center gap-2 self-end">
        <ComposerPrimitive.Cancel asChild>
          <Button
            variant="ghost"
            className="text-[#475569] dark:text-zinc-300 hover:bg-[#eef2ff]/50 dark:hover:bg-zinc-700/50"
          >
            Cancel
          </Button>
        </ComposerPrimitive.Cancel>
        <ComposerPrimitive.Send asChild>
          <Button className="bg-[#4f46e5] dark:bg-[#6366f1] hover:bg-[#4338ca] dark:hover:bg-[#4f46e5] text-white rounded-[2rem]">
            Send
          </Button>
        </ComposerPrimitive.Send>
      </div>
    </ComposerPrimitive.Root>
  );
};

const AssistantMessage: FC = () => {
  const content = useMessage((m) => m.content);
  const markdownText = React.useMemo(() => {
    if (!content) return '';
    if (typeof content === 'string') return content;
    if (Array.isArray(content) && content.length > 0 && 'text' in content[0]) {
      return content[0].text || '';
    }
    return '';
  }, [content]);

  return (
    <MessagePrimitive.Root className="grid grid-cols-[auto_auto_1fr] grid-rows-[auto_1fr] relative w-full max-w-[var(--thread-max-width)] py-4">
      <div className="text-[#1e293b] dark:text-zinc-200 max-w-[calc(var(--thread-max-width)*0.8)] break-words leading-7 col-span-2 col-start-2 row-start-1 my-1.5 bg-white dark:bg-zinc-800 rounded-3xl px-5 py-2.5 border border-[#e2e8f0] dark:border-zinc-700 shadow-sm">
        <MemoryUI />
        <MarkdownRenderer 
          markdownText={markdownText}
          showCopyButton={true}
          isDarkMode={document.documentElement.classList.contains('dark')}
        />
      </div>

      <AssistantActionBar />

      <BranchPicker className="col-start-2 row-start-2 -ml-2 mr-2" />
    </MessagePrimitive.Root>
  );
};

const AssistantActionBar: FC = () => {
  return (
    <ActionBarPrimitive.Root
      hideWhenRunning
      autohideFloat="single-branch"
      className="text-[#475569] dark:text-zinc-300 flex gap-1 col-start-3 row-start-2 ml-1 data-[floating]:bg-white data-[floating]:dark:bg-zinc-800 data-[floating]:absolute data-[floating]:rounded-md data-[floating]:border data-[floating]:border-[#e2e8f0] data-[floating]:dark:border-zinc-700 data-[floating]:p-1 data-[floating]:shadow-sm"
    >
      <ActionBarPrimitive.Copy asChild>
        <TooltipIconButton
          tooltip="Copy"
          className="hover:text-[#4f46e5] dark:hover:text-[#6366f1] hover:bg-[#eef2ff] dark:hover:bg-zinc-700"
        >
          <MessagePrimitive.If copied>
            <CheckIcon />
          </MessagePrimitive.If>
          <MessagePrimitive.If copied={false}>
            <CopyIcon />
          </MessagePrimitive.If>
        </TooltipIconButton>
      </ActionBarPrimitive.Copy>
      <ActionBarPrimitive.Reload asChild>
        <TooltipIconButton
          tooltip="Refresh"
          className="hover:text-[#4f46e5] dark:hover:text-[#6366f1] hover:bg-[#eef2ff] dark:hover:bg-zinc-700"
        >
          <RefreshCwIcon />
        </TooltipIconButton>
      </ActionBarPrimitive.Reload>
    </ActionBarPrimitive.Root>
  );
};

const BranchPicker: FC<BranchPickerPrimitive.Root.Props> = ({
  className,
  ...rest
}) => {
  return (
    <BranchPickerPrimitive.Root
      hideWhenSingleBranch
      className={cn("text-[#475569] dark:text-zinc-300 inline-flex items-center text-xs", className)}
      {...rest}
    >
      <BranchPickerPrimitive.Previous asChild>
        <TooltipIconButton
          tooltip="Previous"
          className="hover:text-[#4f46e5] dark:hover:text-[#6366f1] hover:bg-[#eef2ff] dark:hover:bg-zinc-700"
        >
          <ChevronLeftIcon />
        </TooltipIconButton>
      </BranchPickerPrimitive.Previous>
      <span className="font-medium">
        <BranchPickerPrimitive.Number /> / <BranchPickerPrimitive.Count />
      </span>
      <BranchPickerPrimitive.Next asChild>
        <TooltipIconButton
          tooltip="Next"
          className="hover:text-[#4f46e5] dark:hover:text-[#6366f1] hover:bg-[#eef2ff] dark:hover:bg-zinc-700"
        >
          <ChevronRightIcon />
        </TooltipIconButton>
      </BranchPickerPrimitive.Next>
    </BranchPickerPrimitive.Root>
  );
};

const CircleStopIcon = () => {
  return (
    <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 16" fill="currentColor" width="16" height="16">
      <rect width="10" height="10" x="3" y="3" rx="2" />
    </svg>
  );
};

// Component for reuse in mobile drawer
const ThreadListItem: FC = () => {
  return (
    <ThreadListItemPrimitive.Root className="data-[active]:bg-[#eef2ff] hover:bg-[#eef2ff] dark:hover:bg-zinc-800 dark:data-[active]:bg-zinc-800 focus-visible:bg-[#eef2ff] dark:focus-visible:bg-zinc-800 focus-visible:ring-[#4f46e5] flex items-center gap-2 rounded-lg transition-all focus-visible:outline-none focus-visible:ring-2">
      <ThreadListItemPrimitive.Trigger className="flex-grow px-3 py-2 text-start">
        <p className="text-sm">
          <ThreadListItemPrimitive.Title fallback="New Chat" />
        </p>
      </ThreadListItemPrimitive.Trigger>
      <ThreadListItemPrimitive.Archive asChild>
        <TooltipIconButton
          className="hover:text-[#4f46e5] text-[#475569] dark:text-zinc-300 dark:hover:text-[#6366f1] ml-auto mr-3 size-4 p-0"
          variant="ghost"
          tooltip="Archive thread"
        >
          <ArchiveIcon />
        </TooltipIconButton>
      </ThreadListItemPrimitive.Archive>
    </ThreadListItemPrimitive.Root>
  );
};