import { useEffect, useRef, useState } from "react";
import { attachFile, requestUploadUrl, sendMessage, uploadToPresignedUrl } from "../api/chats";
import { useAuthStore } from "../store/authStore";
import { useChatStore } from "../store/chatStore";
import { buildWsUrl } from "../utils/ws";

export function MessageComposer() {
  const activeChatId = useChatStore((s) => s.activeChatId);
  const prependMessage = useChatStore((s) => s.prependMessage);
  const accessToken = useAuthStore((s) => s.accessToken);
  const [text, setText] = useState("");
  const wsRef = useRef<WebSocket | null>(null);
  const recorderRef = useRef<MediaRecorder | null>(null);
  const chunksRef = useRef<BlobPart[]>([]);
  const [isUploading, setIsUploading] = useState(false);
  const [uploadProgress, setUploadProgress] = useState(0);
  const [uploadError, setUploadError] = useState<string | null>(null);
  const [selectedFile, setSelectedFile] = useState<File | null>(null);
  const [selectedType, setSelectedType] = useState<"file" | "image" | "video" | "audio">("file");
  const [previewUrl, setPreviewUrl] = useState<string | null>(null);
  const [isRecording, setIsRecording] = useState(false);

  useEffect(() => {
    return () => {
      if (previewUrl) {
        URL.revokeObjectURL(previewUrl);
      }
    };
  }, [previewUrl]);

  function getWs(): WebSocket | null {
    if (!accessToken || !activeChatId) {
      return null;
    }
    if (wsRef.current && wsRef.current.readyState === WebSocket.OPEN) {
      return wsRef.current;
    }
    const wsUrl = buildWsUrl(accessToken);
    wsRef.current = new WebSocket(wsUrl);
    return wsRef.current;
  }

  async function handleSend() {
    if (!activeChatId || !text.trim()) {
      return;
    }
    const message = await sendMessage(activeChatId, text.trim(), "text");
    prependMessage(activeChatId, message);
    setText("");
    const ws = getWs();
    ws?.send(JSON.stringify({ event: "typing_stop", payload: { chat_id: activeChatId } }));
  }

  async function handleUpload(file: File, messageType: "file" | "image" | "video" | "audio" | "voice" = "file") {
    if (!activeChatId) {
      return;
    }
    setIsUploading(true);
    setUploadProgress(0);
    setUploadError(null);
    try {
      const upload = await requestUploadUrl(file);
      await uploadToPresignedUrl(upload.upload_url, upload.required_headers, file, setUploadProgress);
      const message = await sendMessage(activeChatId, upload.file_url, messageType);
      await attachFile(message.id, upload.file_url, file.type || "application/octet-stream", file.size);
      prependMessage(activeChatId, message);
    } catch {
      setUploadError("Upload failed. Please try again.");
    } finally {
      setIsUploading(false);
    }
  }

  function inferType(file: File): "file" | "image" | "video" | "audio" {
    if (file.type.startsWith("image/")) {
      return "image";
    }
    if (file.type.startsWith("video/")) {
      return "video";
    }
    if (file.type.startsWith("audio/")) {
      return "audio";
    }
    return "file";
  }

  async function startRecord() {
    try {
      const stream = await navigator.mediaDevices.getUserMedia({ audio: true });
      const recorder = new MediaRecorder(stream);
      chunksRef.current = [];
      recorder.ondataavailable = (e) => chunksRef.current.push(e.data);
      recorder.onstop = async () => {
        const blob = new Blob(chunksRef.current, { type: "audio/webm" });
        const file = new File([blob], `voice-${Date.now()}.webm`, { type: "audio/webm" });
        setIsRecording(false);
        await handleUpload(file, "voice");
      };
      recorderRef.current = recorder;
      recorder.start();
      setIsRecording(true);
    } catch {
      setUploadError("Microphone access denied.");
    }
  }

  function stopRecord() {
    recorderRef.current?.stop();
    recorderRef.current = null;
    setIsRecording(false);
  }

  function selectFile(file: File) {
    setUploadError(null);
    setSelectedFile(file);
    const fileType = inferType(file);
    setSelectedType(fileType);
    if (previewUrl) {
      URL.revokeObjectURL(previewUrl);
    }
    if (fileType === "image" || fileType === "video") {
      setPreviewUrl(URL.createObjectURL(file));
    } else {
      setPreviewUrl(null);
    }
  }

  async function sendSelectedFile() {
    if (!selectedFile) {
      return;
    }
    await handleUpload(selectedFile, selectedType);
    if (previewUrl) {
      URL.revokeObjectURL(previewUrl);
    }
    setSelectedFile(null);
    setPreviewUrl(null);
    setSelectedType("file");
    setUploadProgress(0);
  }

  function cancelSelectedFile() {
    if (previewUrl) {
      URL.revokeObjectURL(previewUrl);
    }
    setSelectedFile(null);
    setPreviewUrl(null);
    setSelectedType("file");
    setUploadProgress(0);
    setUploadError(null);
  }

  function formatBytes(size: number): string {
    if (size < 1024) {
      return `${size} B`;
    }
    if (size < 1024 * 1024) {
      return `${(size / 1024).toFixed(1)} KB`;
    }
    return `${(size / (1024 * 1024)).toFixed(1)} MB`;
  }

  return (
    <div className="border-t border-slate-700 bg-panel p-3">
      <div className="mb-2 flex gap-2">
        <input
          className="flex-1 rounded bg-slate-800 px-3 py-2"
          placeholder="Type message..."
          value={text}
          onChange={(e) => {
            setText(e.target.value);
            if (activeChatId) {
              const ws = getWs();
              ws?.send(JSON.stringify({ event: "typing_start", payload: { chat_id: activeChatId } }));
            }
          }}
        />
        <button className="rounded bg-accent px-3 py-2 font-semibold text-black" onClick={handleSend}>
          Send
        </button>
      </div>
      {selectedFile ? (
        <div className="mb-2 rounded border border-slate-700 bg-slate-900 p-3 text-sm">
          <div className="mb-2 font-semibold">Ready to send</div>
          <div className="mb-1 break-all text-slate-300">{selectedFile.name}</div>
          <div className="mb-2 text-xs text-slate-400">{formatBytes(selectedFile.size)}</div>
          {previewUrl && selectedType === "image" ? (
            <img className="mb-2 max-h-56 rounded object-contain" src={previewUrl} alt={selectedFile.name} />
          ) : null}
          {previewUrl && selectedType === "video" ? (
            <video className="mb-2 max-h-56 w-full rounded" src={previewUrl} controls muted />
          ) : null}
          {isUploading ? (
            <div className="mb-2">
              <div className="mb-1 text-xs text-slate-300">Uploading: {uploadProgress}%</div>
              <div className="h-2 rounded bg-slate-700">
                <div className="h-2 rounded bg-accent transition-all" style={{ width: `${uploadProgress}%` }} />
              </div>
            </div>
          ) : null}
          <div className="flex gap-2">
            <button
              className="rounded bg-accent px-3 py-1 font-semibold text-black disabled:opacity-50"
              onClick={() => void sendSelectedFile()}
              disabled={isUploading}
            >
              Send media
            </button>
            <button className="rounded bg-slate-700 px-3 py-1 disabled:opacity-50" onClick={cancelSelectedFile} disabled={isUploading}>
              Cancel
            </button>
          </div>
        </div>
      ) : null}
      {uploadError ? <div className="mb-2 text-sm text-red-400">{uploadError}</div> : null}
      <div className="flex items-center gap-2 text-sm">
        <label className="cursor-pointer rounded bg-slate-700 px-3 py-1">
          Upload
          <input
            className="hidden"
            type="file"
            disabled={isUploading}
            onChange={(e) => {
              const file = e.target.files?.[0];
              if (file) {
                selectFile(file);
              }
              e.currentTarget.value = "";
            }}
          />
        </label>
        <button className="rounded bg-slate-700 px-3 py-1 disabled:opacity-50" onClick={startRecord} disabled={isUploading || isRecording}>
          {isRecording ? "Recording..." : "Record Voice"}
        </button>
        <button className="rounded bg-slate-700 px-3 py-1 disabled:opacity-50" onClick={stopRecord} disabled={!isRecording}>
          Stop
        </button>
      </div>
    </div>
  );
}