"use client";

import { AnimatePresence } from "framer-motion";
import React, { useEffect, useRef, useState } from "react";
import QueryInput from "../home/queryinput";
import { cn } from "@repo/ui/lib/utils";
import { motion } from "framer-motion";
import { useRouter } from "next/navigation";
import { ChatHistory, sourcesZod } from "@repo/shared-types";
import {
  Accordion,
  AccordionContent,
  AccordionItem,
  AccordionTrigger,
} from "@repo/ui/shadcn/accordion";
import Markdown from "react-markdown";
import remarkGfm from "remark-gfm";
import remarkMath from "remark-math";
import rehypeKatex from "rehype-katex";
import rehypeHighlight from "rehype-highlight";
import { code, p } from "./markdownRenderHelpers";
import { codeLanguageSubset } from "@/lib/constants";
import { toast } from "sonner";
import Link from "next/link";
import { createChatObject } from "@/app/actions/doers";
import { ClipboardIcon } from "@heroicons/react/24/outline";
import { SendIcon } from "lucide-react";

function ChatWindow({
  q,
  spaces,
  initialChat = [
    {
      question: q,
      answer: {
        parts: [],
        sources: [],
      },
    },
  ],
  threadId,
}: {
  q: string;
  spaces: { id: string; name: string }[];
  initialChat?: ChatHistory[];
  threadId: string;
}) {
  const [layout, setLayout] = useState<"chat" | "initial">(
    initialChat.length > 1 ? "chat" : "initial",
  );
  const [chatHistory, setChatHistory] = useState<ChatHistory[]>(initialChat);

  const removeJustificationFromText = (text: string) => {
    // remove everything after the first "<justification>" word
    const justificationLine = text.indexOf("<justification>");
    if (justificationLine !== -1) {
      // Add that justification to the last chat message
      const lastChatMessage = chatHistory[chatHistory.length - 1];
      if (lastChatMessage) {
        lastChatMessage.answer.justification = text.slice(justificationLine);
      }
      return text.slice(0, justificationLine);
    }
    return text;
  };

  const router = useRouter();

  const getAnswer = async (query: string, spaces: string[]) => {
    const sourcesFetch = await fetch(
      `/api/chat?q=${query}&spaces=${spaces}&sourcesOnly=true&threadId=${threadId}`,
      {
        method: "POST",
        body: JSON.stringify({ chatHistory }),
      },
    );

    // TODO: handle this properly
    const sources = await sourcesFetch.json();

    const sourcesParsed = sourcesZod.safeParse(sources);

    if (!sourcesParsed.success) {
      console.error(sourcesParsed.error);
      toast.error("Something went wrong while getting the sources");
      return;
    }
    window.scrollTo({
      top: document.documentElement.scrollHeight,
      behavior: "smooth",
    });

    const updateChatHistoryAndFetch = async () => {
      // Step 1: Update chat history with the assistant's response
      await new Promise((resolve) => {
        setChatHistory((prevChatHistory) => {
          const newChatHistory = [...prevChatHistory];
          const lastAnswer = newChatHistory[newChatHistory.length - 1];
          if (!lastAnswer) {
            resolve(undefined);
            return prevChatHistory;
          }

          const filteredSourceUrls = new Set(
            sourcesParsed.data.metadata.map((source) => source.url),
          );
          const uniqueSources = sourcesParsed.data.metadata.filter((source) => {
            if (filteredSourceUrls.has(source.url)) {
              filteredSourceUrls.delete(source.url);
              return true;
            }
            return false;
          });

          lastAnswer.answer.sources = uniqueSources.map((source) => ({
            title: source.title ?? "Untitled",
            type: source.type ?? "page",
            source: source.url ?? "https://supermemory.ai",
            content: source.description ?? "No content available",
            numChunks: sourcesParsed.data.metadata.filter(
              (f) => f.url === source.url,
            ).length,
          }));

          resolve(newChatHistory);
          return newChatHistory;
        });
      });

      // Step 2: Fetch data from the API
      const resp = await fetch(
        `/api/chat?q=${query}&spaces=${spaces}&threadId=${threadId}`,
        {
          method: "POST",
          body: JSON.stringify({ chatHistory, sources: sourcesParsed.data }),
        },
      );

      // Step 3: Read the response stream and update the chat history
      const reader = resp.body?.getReader();
      let done = false;
      while (!done && reader) {
        const { value, done: d } = await reader.read();
        if (d) {
          setChatHistory((prevChatHistory) => {
            createChatObject(threadId, prevChatHistory);
            return prevChatHistory;
          });
        }
        done = d;

        const txt = new TextDecoder().decode(value);
        setChatHistory((prevChatHistory) => {
          const newChatHistory = [...prevChatHistory];
          const lastAnswer = newChatHistory[newChatHistory.length - 1];
          if (!lastAnswer) return prevChatHistory;

          window.scrollTo({
            top: document.documentElement.scrollHeight,
            behavior: "smooth",
          });

          lastAnswer.answer.parts.push({ text: txt });
          return newChatHistory;
        });
      }
    };

    updateChatHistoryAndFetch();
  };

  useEffect(() => {
    if (q.trim().length > 0 || chatHistory.length > 0) {
      setLayout("chat");
      const lastChat = chatHistory.length > 0 ? chatHistory.length - 1 : 0;
      const startGenerating = chatHistory[lastChat]?.answer.parts[0]?.text
        ? false
        : true;
      if (startGenerating) {
        getAnswer(
          q,
          spaces.map((s) => `${s}`),
        );
      }
    } else {
      router.push("/home");
    }
  }, []);

  return (
    <div className="h-full">
      <AnimatePresence mode="popLayout">
        {layout === "initial" ? (
          <motion.div
            exit={{ opacity: 0 }}
            key="initial"
            className="max-w-3xl h-full justify-center items-center flex mx-auto w-full flex-col"
          >
            <div className="w-full h-96">
              <QueryInput
                handleSubmit={() => {}}
                initialQuery={q}
                initialSpaces={[]}
                disabled
              />
            </div>
          </motion.div>
        ) : (
          <div
            className="max-w-3xl z-10 mx-auto relative h-full overflow-y-auto no-scrollbar"
            key="chat"
          >
            <div className="w-full pt-24 mb-40">
              {chatHistory.map((chat, idx) => (
                <div key={idx} className="space-y-16">
                  <div
                    className={`mt-8 ${idx != chatHistory.length - 1 ? "pb-2 border-b border-b-gray-400" : ""}`}
                  >
                    <h2
                      className={cn(
                        "text-white transition-all transform translate-y-0 opacity-100 duration-500 ease-in-out font-semibold text-xl",
                      )}
                    >
                      {chat.question}
                    </h2>

                    <div className="flex flex-col">
                      {/* Related memories */}
                      <div
                        className={`space-y-4 ${chat.answer.sources.length > 0 || chat.answer.parts.length === 0 ? "flex" : "hidden"}`}
                      >
                        <Accordion
                          defaultValue={
                            idx === chatHistory.length - 1 ? "memories" : ""
                          }
                          type="single"
                          collapsible
                        >
                          <AccordionItem value="memories">
                            <AccordionTrigger className="text-foreground-menu">
                              Related Memories
                            </AccordionTrigger>
                            {/* TODO: fade out content on the right side, the fade goes away when the user scrolls */}
                            <AccordionContent
                              className="flex items-center no-scrollbar overflow-auto gap-4 relative max-w-3xl no-scrollbar"
                              defaultChecked
                            >
                              {/* Loading state */}
                              {chat.answer.sources.length > 0 ||
                                (chat.answer.parts.length === 0 && (
                                  <>
                                    {[1, 2, 3, 4].map((_, idx) => (
                                      <div
                                        key={`loadingState-${idx}`}
                                        className="w-[350px] shrink-0 p-4 gap-2 rounded-2xl flex flex-col bg-secondary animate-pulse"
                                      >
                                        <div className="bg-slate-700 h-2 rounded-full w-1/2"></div>
                                        <div className="bg-slate-700 h-2 rounded-full w-full"></div>
                                      </div>
                                    ))}
                                  </>
                                ))}
                              {chat.answer.sources.map((source, idx) => (
                                <Link
                                  href={source.source}
                                  key={idx}
                                  className="w-[350px] shrink-0 p-4 gap-2 rounded-2xl flex flex-col bg-secondary"
                                >
                                  <div className="flex justify-between text-foreground-menu text-sm">
                                    <span>{source.type}</span>

                                    {source.numChunks > 1 && (
                                      <span>{source.numChunks} chunks</span>
                                    )}
                                  </div>
                                  <div className="text-base">
                                    {source.title}
                                  </div>
                                  <div className="text-xs line-clamp-2">
                                    {source.content.length > 100
                                      ? source.content.slice(0, 100) + "..."
                                      : source.content}
                                  </div>
                                </Link>
                              ))}
                            </AccordionContent>
                          </AccordionItem>
                        </Accordion>
                      </div>

                      {/* Summary */}
                      <div>
                        <div className="text-foreground-menu py-2">Summary</div>
                        <div className="text-base">
                          {/* Loading state */}
                          {(chat.answer.parts.length === 0 ||
                            chat.answer.parts.join("").length === 0) && (
                            <div className="animate-pulse flex space-x-4">
                              <div className="flex-1 space-y-3 py-1">
                                <div className="h-2 bg-slate-700 rounded"></div>
                                <div className="h-2 bg-slate-700 rounded"></div>
                              </div>
                            </div>
                          )}

                          <Markdown
                            remarkPlugins={[remarkGfm, [remarkMath]]}
                            rehypePlugins={[
                              rehypeKatex,
                              [
                                rehypeHighlight,
                                {
                                  detect: true,
                                  ignoreMissing: true,
                                  subset: codeLanguageSubset,
                                },
                              ],
                            ]}
                            components={{
                              code: code as any,
                              p: p as any,
                            }}
                            className="flex flex-col gap-2 text-base"
                          >
                            {removeJustificationFromText(
                              chat.answer.parts
                                .map((part) => part.text)
                                .join(""),
                            )}
                          </Markdown>

                          <div className="mt-3 relative -left-2 flex items-center gap-1">
                            {/* TODO: speak response */}
                            {/* <button className="group h-8 w-8 flex justify-center items-center active:scale-75 duration-200">
                              <SpeakerWaveIcon className="size-[18px] group-hover:text-primary" />
                            </button> */}
                            {/* copy response */}
                            <button
                              onClick={() =>
                                navigator.clipboard.writeText(
                                  chat.answer.parts
                                    .map((part) => part.text)
                                    .join(""),
                                )
                              }
                              className="group h-8 w-8 flex justify-center items-center active:scale-75 duration-200"
                            >
                              <ClipboardIcon className="size-[18px] group-hover:text-primary" />
                            </button>
                            <button
                              onClick={async () => {
                                const isWebShareSupported =
                                  navigator.share !== undefined;
                                if (isWebShareSupported) {
                                  try {
                                    await navigator.share({
                                      title: "Your Share Title",
                                      text: "Your share text or description",
                                      url: "https://your-url-to-share.com",
                                    });
                                  } catch (e) {
                                    console.error("Error sharing:", e);
                                  }
                                } else {
                                  console.error("web share is not supported!");
                                }
                              }}
                              className="group h-8 w-8 flex justify-center items-center active:scale-75 duration-200"
                            >
                              <SendIcon className="size-[18px] group-hover:text-primary" />
                            </button>
                          </div>
                        </div>
                      </div>
                      {/* Justification */}
                      {chat.answer.justification &&
                        chat.answer.justification.length && (
                          <div
                            className={`${chat.answer.justification && chat.answer.justification.length > 0 ? "flex" : "hidden"}`}
                          >
                            <Accordion
                              defaultValue={""}
                              type="single"
                              collapsible
                            >
                              <AccordionItem value="justification">
                                <AccordionTrigger className="text-foreground-menu">
                                  Justification
                                </AccordionTrigger>
                                <AccordionContent
                                  className="relative flex gap-2 max-w-3xl overflow-auto no-scrollbar"
                                  defaultChecked
                                >
                                  {chat.answer.justification.length > 0
                                    ? chat.answer.justification
                                        .replaceAll("<justification>", "")
                                        .replaceAll("</justification>", "")
                                    : "No justification provided."}
                                </AccordionContent>
                              </AccordionItem>
                            </Accordion>
                          </div>
                        )}
                    </div>
                  </div>
                </div>
              ))}
            </div>

            <div className="fixed bottom-4 w-full max-w-3xl">
              <QueryInput
                mini
                className="w-full shadow-md"
                initialQuery={""}
                initialSpaces={[]}
                handleSubmit={async (q, spaces) => {
                  setChatHistory((prevChatHistory) => {
                    return [
                      ...prevChatHistory,
                      {
                        question: q,
                        answer: {
                          parts: [],
                          sources: [],
                        },
                      },
                    ];
                  });
                  await getAnswer(
                    q,
                    spaces.map((s) => `${s.id}`),
                  );
                }}
              />
            </div>
          </div>
        )}
      </AnimatePresence>
    </div>
  );
}

export default ChatWindow;