import type { FileAttachmentDto } from "@mrp/shared";
import { permissions } from "@mrp/shared";
import { useEffect, useState } from "react";

import { useAuth } from "../../auth/AuthProvider";
import { api, ApiError } from "../../lib/api";

interface CrmAttachmentsPanelProps {
  ownerType: string;
  ownerId: string;
  onAttachmentCountChange?: (count: number) => void;
}

function formatFileSize(sizeBytes: number) {
  if (sizeBytes < 1024) {
    return `${sizeBytes} B`;
  }

  if (sizeBytes < 1024 * 1024) {
    return `${(sizeBytes / 1024).toFixed(1)} KB`;
  }

  return `${(sizeBytes / (1024 * 1024)).toFixed(1)} MB`;
}

export function CrmAttachmentsPanel({ ownerType, ownerId, onAttachmentCountChange }: CrmAttachmentsPanelProps) {
  const { token, user } = useAuth();
  const [attachments, setAttachments] = useState<FileAttachmentDto[]>([]);
  const [status, setStatus] = useState("Loading attachments...");
  const [isUploading, setIsUploading] = useState(false);
  const [deletingAttachmentId, setDeletingAttachmentId] = useState<string | null>(null);

  const canReadFiles = user?.permissions.includes(permissions.filesRead) ?? false;
  const canWriteFiles = user?.permissions.includes(permissions.filesWrite) ?? false;

  useEffect(() => {
    if (!token || !canReadFiles) {
      return;
    }

    api
      .getAttachments(token, ownerType, ownerId)
      .then((nextAttachments) => {
        setAttachments(nextAttachments);
        onAttachmentCountChange?.(nextAttachments.length);
        setStatus(
          nextAttachments.length === 0 ? "No attachments uploaded yet." : `${nextAttachments.length} attachment(s) available.`
        );
      })
      .catch((error: unknown) => {
        const message = error instanceof ApiError ? error.message : "Unable to load attachments.";
        setStatus(message);
      });
  }, [canReadFiles, onAttachmentCountChange, ownerId, ownerType, token]);

  async function handleUpload(event: React.ChangeEvent<HTMLInputElement>) {
    const file = event.target.files?.[0];
    if (!file || !token || !canWriteFiles) {
      return;
    }

    setIsUploading(true);
    setStatus("Uploading attachment...");

    try {
      const attachment = await api.uploadFile(token, file, ownerType, ownerId);
      setAttachments((current) => {
        const nextAttachments = [attachment, ...current];
        onAttachmentCountChange?.(nextAttachments.length);
        return nextAttachments;
      });
      setStatus("Attachment uploaded.");
    } catch (error: unknown) {
      const message = error instanceof ApiError ? error.message : "Unable to upload attachment.";
      setStatus(message);
    } finally {
      setIsUploading(false);
      event.target.value = "";
    }
  }

  async function handleOpen(attachment: FileAttachmentDto) {
    if (!token) {
      return;
    }

    try {
      const blob = await api.getFileContentBlob(token, attachment.id);
      const objectUrl = window.URL.createObjectURL(blob);
      window.open(objectUrl, "_blank", "noopener,noreferrer");
      window.setTimeout(() => window.URL.revokeObjectURL(objectUrl), 60_000);
    } catch (error: unknown) {
      const message = error instanceof ApiError ? error.message : "Unable to open attachment.";
      setStatus(message);
    }
  }

  async function handleDelete(attachment: FileAttachmentDto) {
    if (!token || !canWriteFiles) {
      return;
    }

    setDeletingAttachmentId(attachment.id);
    setStatus(`Deleting ${attachment.originalName}...`);

    try {
      await api.deleteAttachment(token, attachment.id);
      setAttachments((current) => {
        const nextAttachments = current.filter((item) => item.id !== attachment.id);
        onAttachmentCountChange?.(nextAttachments.length);
        return nextAttachments;
      });
      setStatus("Attachment deleted.");
    } catch (error: unknown) {
      const message = error instanceof ApiError ? error.message : "Unable to delete attachment.";
      setStatus(message);
    } finally {
      setDeletingAttachmentId(null);
    }
  }

  return (
    <article className="min-w-0 rounded-[28px] border border-line/70 bg-surface/90 p-4 shadow-panel 2xl:p-5">
      <div className="flex flex-col gap-3 lg:flex-row lg:items-start lg:justify-between">
        <div>
          <p className="text-xs font-semibold uppercase tracking-[0.24em] text-muted">Attachments</p>
          <h4 className="mt-2 text-lg font-bold text-text">Shared files</h4>
          <p className="mt-2 text-sm text-muted">
            Drawings, customer markups, vendor documents, and other reference files linked to this record.
          </p>
        </div>
        {canWriteFiles ? (
          <label className="inline-flex cursor-pointer items-center justify-center rounded-2xl bg-brand px-2 py-2 text-sm font-semibold text-white">
            {isUploading ? "Uploading..." : "Upload file"}
            <input className="hidden" type="file" onChange={handleUpload} disabled={isUploading} />
          </label>
        ) : null}
      </div>
      <div className="mt-5 rounded-2xl border border-line/70 bg-page/70 px-2 py-2 text-sm text-muted">{status}</div>
      {!canReadFiles ? (
        <div className="mt-5 rounded-3xl border border-dashed border-line/70 bg-page/60 px-4 py-8 text-center text-sm text-muted">
          You do not have permission to view file attachments.
        </div>
      ) : attachments.length === 0 ? (
        <div className="mt-5 rounded-3xl border border-dashed border-line/70 bg-page/60 px-4 py-8 text-center text-sm text-muted">
          No attachments have been added to this record yet.
        </div>
      ) : (
        <div className="mt-5 space-y-3">
          {attachments.map((attachment) => (
            <div
              key={attachment.id}
              className="flex flex-col gap-2 rounded-3xl border border-line/70 bg-page/60 px-2 py-2 lg:flex-row lg:items-center lg:justify-between"
            >
              <div className="min-w-0">
                <p className="truncate text-sm font-semibold text-text">{attachment.originalName}</p>
                <p className="mt-1 text-xs text-muted">
                  {attachment.mimeType} · {formatFileSize(attachment.sizeBytes)} · {new Date(attachment.createdAt).toLocaleString()}
                </p>
              </div>
              <div className="flex shrink-0 gap-3">
                <button
                  type="button"
                  onClick={() => handleOpen(attachment)}
                  className="rounded-2xl border border-line/70 px-4 py-2 text-sm font-semibold text-text"
                >
                  Open
                </button>
                {canWriteFiles ? (
                  <button
                    type="button"
                    onClick={() => handleDelete(attachment)}
                    disabled={deletingAttachmentId === attachment.id}
                    className="rounded-2xl border border-rose-400/40 px-4 py-2 text-sm font-semibold text-rose-700 disabled:cursor-not-allowed disabled:opacity-60 dark:text-rose-300"
                  >
                    {deletingAttachmentId === attachment.id ? "Deleting..." : "Delete"}
                  </button>
                ) : null}
              </div>
            </div>
          ))}
        </div>
      )}
    </article>
  );
}