import React, {
  Dispatch,
  SetStateAction,
  useCallback,
  useState,
  memo,
  useRef,
} from "react";
import axios from "axios";
import { ArrowUpTrayIcon } from "@heroicons/react/24/outline";
import { compact } from "lodash";

import LoadingText from "./LoadingText";
import { FileLite } from "../types/file";
import FileViewerList from "./FileViewerList";

type FileUploadAreaProps = {
  handleSetFiles: Dispatch<SetStateAction<FileLite[]>>;
  maxNumFiles: number;
  maxFileSizeMB: number;
};

function FileUploadArea(props: FileUploadAreaProps) {
  const handleSetFiles = props.handleSetFiles;

  const [files, setFiles] = useState<FileLite[]>([]);
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState("");
  const [dragOver, setDragOver] = useState(false);
  const dropzoneRef = useRef<HTMLLabelElement>(null);

  const handleFileChange = useCallback(
    async (selectedFiles: FileList | null) => {
      if (selectedFiles && selectedFiles.length > 0) {
        setError("");

        if (files.length + selectedFiles.length > props.maxNumFiles) {
          setError(`You can only upload up to ${props.maxNumFiles} files.`);
          if (dropzoneRef.current) {
            (dropzoneRef.current as any).value = "";
          }
          return;
        }

        setLoading(true);

        const uploadedFiles = await Promise.all(
          Array.from(selectedFiles).map(async (file) => {
            // Check the file type
            if (
              file.type.match(
                /(text\/plain|application\/(pdf|msword|vnd\.openxmlformats-officedocument\.wordprocessingml\.document)|text\/(markdown|x-markdown))/
              ) && // AND file isn't too big
              file.size < props.maxFileSizeMB * 1024 * 1024
            ) {
              // Check if the file name already exists in the files state
              if (files.find((f) => f.name === file.name)) {
                return null; // Skip this file
              }

              const formData = new FormData();
              formData.append("file", file);
              formData.append("filename", file.name);

              try {
                const processFileResponse = await axios.post(
                  "/api/process-file",
                  formData,
                  {
                    headers: {
                      "Content-Type": "multipart/form-data",
                    },
                  }
                );

                if (processFileResponse.status === 200) {
                  const text = processFileResponse.data.text;
                  const meanEmbedding = processFileResponse.data.meanEmbedding;
                  const chunks = processFileResponse.data.chunks;

                  const fileObject: FileLite = {
                    name: file.name,
                    url: URL.createObjectURL(file),
                    type: file.type,
                    size: file.size,
                    expanded: false,
                    embedding: meanEmbedding,
                    chunks,
                    extractedText: text,
                  };
                  console.log(fileObject);

                  return fileObject;
                } else {
                  console.log("Error creating file embedding");
                  return null;
                }
              } catch (err: any) {
                console.log(`Error creating file embedding: ${err}`);
                return null;
              }
            } else {
              alert(
                `Invalid file type or size. Only TXT, PDF, DOCX or MD are allowed, up to ${props.maxFileSizeMB}MB.`
              );
              return null; // Skip this file
            }
          })
        );

        // Filter out any null values from the uploadedFiles array
        const validFiles = compact(uploadedFiles);

        // Set the files state with the valid files and the existing files
        setFiles((prevFiles) => [...prevFiles, ...validFiles]);
        handleSetFiles((prevFiles) => [...prevFiles, ...validFiles]);

        setLoading(false);
      }
    },
    [files, handleSetFiles, props.maxFileSizeMB, props.maxNumFiles]
  );

  const handleDragEnter = useCallback((event: React.DragEvent) => {
    event.preventDefault();
    setDragOver(true);
  }, []);

  const handleDragOver = useCallback((event: React.DragEvent) => {
    event.preventDefault();
  }, []);

  const handleDragLeave = useCallback((event: React.DragEvent) => {
    event.preventDefault();
    setDragOver(false);
  }, []);

  const handleDrop = useCallback(
    (event: React.DragEvent) => {
      event.preventDefault();
      setDragOver(false);
      const droppedFiles = event.dataTransfer.files;
      handleFileChange(droppedFiles);
    },
    [handleFileChange]
  );

  return (
    <div className="flex items-center justify-center w-full flex-col">
      <label
        htmlFor="dropzone-file"
        className={`flex flex-col shadow items-center justify-center w-full h-36 border-2 border-gray-300 border-dashed rounded-lg cursor-pointer bg-gray-50 hover:bg-gray-100 relative ${
          dragOver ? "border-blue-500 bg-blue-50" : ""
        }`}
        ref={dropzoneRef}
        onDragEnter={handleDragEnter}
        onDragOver={handleDragOver}
        onDragLeave={handleDragLeave}
        onDrop={handleDrop}
      >
        <div className="flex flex-col items-center justify-center pt-5 pb-6">
          {loading ? (
            <LoadingText text="Uploading..." />
          ) : (
            <div className="text-gray-500 flex flex-col items-center text-center">
              <ArrowUpTrayIcon className="w-7 h-7 mb-4" />
              <p className="mb-2 text-sm">
                <span className="font-semibold">Click to upload</span> or drag
                and drop
              </p>
              <p className="text-xs">
                TXT, PDF, DOCX or MD (max {props.maxFileSizeMB}MB per file)
              </p>
              <p className="text-xs mt-1">
                You can upload up to {props.maxNumFiles - files.length} more{" "}
                {props.maxNumFiles - files.length === 1 ? "file" : "files"}
              </p>
              <input
                id="dropzone-file"
                type="file"
                className="hidden"
                multiple
                onChange={(event) => handleFileChange(event.target.files)}
              />
            </div>
          )}
        </div>
      </label>

      {error && (
        <div className="flex items-center justify-center w-full mt-4">
          <p className="text-sm text-red-500">{error}</p>
        </div>
      )}

      <FileViewerList files={files} title="Uploaded Files" />
    </div>
  );
}

export default memo(FileUploadArea);