fixin.me/app/javascript/controllers/drag_controller.js

import { Controller } from "@hotwired/stimulus"

// Shared across all instances — drag spans multiple elements
let lastEnterTime

export default class extends Controller {
  static values = {
    dragPath: String,
    dropId: String,
    dropIdParam: String
  }

  start(event) {
    lastEnterTime = event.timeStamp
    this.element.closest("table").querySelectorAll("thead tr").forEach(tr => {
      tr.toggleAttribute("hidden")
    })
    event.dataTransfer.setData("text/plain", this.dragPathValue)
    const rect = this.element.getBoundingClientRect()
    event.dataTransfer.setDragImage(this.element, event.x - rect.left, event.y - rect.top)
    event.dataTransfer.dropEffect = "move"
  }

  end(event) {
    this.leave(event)
    this.element.closest("table").querySelectorAll("thead tr").forEach(tr => {
      tr.toggleAttribute("hidden")
    })
  }

  enter(event) {
    this.leave(event)
    lastEnterTime = event.timeStamp
    document.getElementById(this.dropIdValue)?.classList.add("dropzone")
  }

  over(event) {
    event.preventDefault()
  }

  leave(event) {
    if (event.timeStamp <= lastEnterTime) return
    this.element.closest("table").querySelectorAll(".dropzone").forEach(tr => {
      tr.classList.remove("dropzone")
    })
  }

  drop(event) {
    event.preventDefault()
    const id = this.dropIdValue.split("_").pop()
    const form = document.createElement('form')
    form.action = event.dataTransfer.getData("text/plain")
    form.method = 'post'
    form.dataset.turboStream = 'true'
    const input = document.createElement('input')
    input.type = 'hidden'; input.name = this.dropIdParamValue; input.value = id
    form.appendChild(input)
    form.addEventListener('turbo:submit-end', () => form.remove())
    document.body.appendChild(form)
    form.requestSubmit()
  }
}