// --------- Preload scripts loading ---------
function domReady(condition = ['complete', 'interactive']) {
  return new Promise((resolve) => {
    if (condition.includes(document.readyState)) {
      resolve(true)
    }
    else {
      document.addEventListener('readystatechange', () => {
        if (condition.includes(document.readyState)) {
          resolve(true)
        }
      })
    }
  })
}

const safeDOM = {
  append(parent, child) {
    if (!Array.from(parent.children).find(e => e === child)) {
      parent.appendChild(child)
    }
  },
  remove(parent, child) {
    if (Array.from(parent.children).find(e => e === child)) {
      parent.removeChild(child)
    }
  },
}

/**
 * https://tobiasahlin.com/spinkit
 * https://connoratherton.com/loaders
 * https://projects.lukehaas.me/css-loaders
 * https://matejkustec.github.io/SpinThatShit
 */
function useLoading() {
  const className = 'electron-loading'
  const loginStyles = `
  .${className}-core {
    font-size: 30px;
    text-indent: -9999em;
    overflow: hidden;
    width: 1em;
    height: 1em;
    border-radius: 50%;
    margin: 72px auto;
    position: relative;
    -webkit-transform: translateZ(0);
    -ms-transform: translateZ(0);
    transform: translateZ(0);
    -webkit-animation: electron-loading-dots 1.7s infinite ease, electron-loading-spin 1.7s infinite ease;
    animation: electron-loading-dots 1.7s infinite ease, electron-loading-spin 1.7s infinite ease;
  }

  @-webkit-keyframes electron-loading-dots {
    0% {
      box-shadow: 0 -0.83em 0 -0.4em, 0 -0.83em 0 -0.42em, 0 -0.83em 0 -0.44em, 0 -0.83em 0 -0.46em, 0 -0.83em 0 -0.477em;
    }
    5%,
    95% {
      box-shadow: 0 -0.83em 0 -0.4em, 0 -0.83em 0 -0.42em, 0 -0.83em 0 -0.44em, 0 -0.83em 0 -0.46em, 0 -0.83em 0 -0.477em;
    }
    10%,
    59% {
      box-shadow: 0 -0.83em 0 -0.4em, -0.087em -0.825em 0 -0.42em, -0.173em -0.812em 0 -0.44em, -0.256em -0.789em 0 -0.46em, -0.297em -0.775em 0 -0.477em;
    }
    20% {
      box-shadow: 0 -0.83em 0 -0.4em, -0.338em -0.758em 0 -0.42em, -0.555em -0.617em 0 -0.44em, -0.671em -0.488em 0 -0.46em, -0.749em -0.34em 0 -0.477em;
    }
    38% {
      box-shadow: 0 -0.83em 0 -0.4em, -0.377em -0.74em 0 -0.42em, -0.645em -0.522em 0 -0.44em, -0.775em -0.297em 0 -0.46em, -0.82em -0.09em 0 -0.477em;
    }
    100% {
      box-shadow: 0 -0.83em 0 -0.4em, 0 -0.83em 0 -0.42em, 0 -0.83em 0 -0.44em, 0 -0.83em 0 -0.46em, 0 -0.83em 0 -0.477em;
    }
  }

  @keyframes electron-loading-dots {
    0% {
      box-shadow: 0 -0.83em 0 -0.4em, 0 -0.83em 0 -0.42em, 0 -0.83em 0 -0.44em, 0 -0.83em 0 -0.46em, 0 -0.83em 0 -0.477em;
    }
    5%,
    95% {
      box-shadow: 0 -0.83em 0 -0.4em, 0 -0.83em 0 -0.42em, 0 -0.83em 0 -0.44em, 0 -0.83em 0 -0.46em, 0 -0.83em 0 -0.477em;
    }
    10%,
    59% {
      box-shadow: 0 -0.83em 0 -0.4em, -0.087em -0.825em 0 -0.42em, -0.173em -0.812em 0 -0.44em, -0.256em -0.789em 0 -0.46em, -0.297em -0.775em 0 -0.477em;
    }
    20% {
      box-shadow: 0 -0.83em 0 -0.4em, -0.338em -0.758em 0 -0.42em, -0.555em -0.617em 0 -0.44em, -0.671em -0.488em 0 -0.46em, -0.749em -0.34em 0 -0.477em;
    }
    38% {
      box-shadow: 0 -0.83em 0 -0.4em, -0.377em -0.74em 0 -0.42em, -0.645em -0.522em 0 -0.44em, -0.775em -0.297em 0 -0.46em, -0.82em -0.09em 0 -0.477em;
    }
    100% {
      box-shadow: 0 -0.83em 0 -0.4em, 0 -0.83em 0 -0.42em, 0 -0.83em 0 -0.44em, 0 -0.83em 0 -0.46em, 0 -0.83em 0 -0.477em;
    }
  }

  @-webkit-keyframes electron-loading-spin {
    0% {
      -webkit-transform: rotate(0deg);
      transform: rotate(0deg);
    }
    100% {
      -webkit-transform: rotate(360deg);
      transform: rotate(360deg);
    }
  }

  @keyframes electron-loading-spin {
    0% {
      -webkit-transform: rotate(0deg);
      transform: rotate(0deg);
    }
    100% {
      -webkit-transform: rotate(360deg);
      transform: rotate(360deg);
    }
  }

  .${className}-wrap {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 3000;
    background: white;
    color: #028D71;
  }

  .${className}-text {
    margin-top: -45px;
  }
    `

  const styleEl = document.createElement('style')
  styleEl.id = `${className}-style`
  styleEl.innerHTML = loginStyles

  const divEl = document.createElement('div')
  divEl.className = `${className}-wrap`
  divEl.innerHTML = `
    <div class="${className}-core"></div>
    <div class="${className}-text"> 初始化服务中...</div>
  `

  return {
    appendLoading() {
      safeDOM.append(document.head, styleEl)
      safeDOM.append(document.body, divEl)
    },
    removeLoading() {
      safeDOM.remove(document.head, styleEl)
      safeDOM.remove(document.body, divEl)
    },
  }
}

// ----------------------------------------------------------------------

const { appendLoading, removeLoading } = useLoading()
domReady().then(appendLoading)

window.onmessage = (ev) => {
  ev.data.payload === 'removeLoading' && removeLoading()
}

setTimeout(removeLoading, 4999)