/*
 * v.js
 * Copyright (C) 2024 veypi <i@veypi.com>
 *
 * Distributed under terms of the GPL license.
 */

(function () {
  'use strict';

  const config = { childList: true, subtree: true };

  const callback = function (mutationsList, observer) {
    for (let mutation of mutationsList) {
      if (mutation.type === 'childList') {
        // console.log(mutation)
        // console.log('A child node has been added or removed.');
      }
    }
  };

  const observer = new MutationObserver(callback);

  var cacheUrl = {}
  var pendingRequests = {};

  async function fetchFileWithCache(url) {
    if (cacheUrl[url]) {
      return Promise.resolve(cacheUrl[url]);
    }
    if (pendingRequests[url]) {
      return pendingRequests[url];
    }
    const promise = fetch(url)
      .then(response => {
        if (!response.ok) {
          throw new Error(`HTTP error! status: ${response.status}`);
        }
        return response.text();
      })
      .then(txt => {
        cacheUrl[url] = txt;
        return txt;
      })
      .catch(error => {
        console.error('Error fetching the file:', error);
        delete pendingRequests[url];
        throw error;
      })
      .finally(() => {
        delete pendingRequests[url];
      });
    pendingRequests[url] = promise;
    return promise;
  }


  function extractBodyAndScript(htmlString) {
    const bodyMatch = htmlString.match(/<body[^>]*>([\s\S]*)<\/body>/i);
    const bodyContent = bodyMatch ? bodyMatch[1] : '';

    let scriptMatches = htmlString.match(/<script[^>]*>([\s\S]*?)<\/script>/ig);


    let scriptContents = []
    let srcReg = /<script\s+[^>]*src=["']([^"']+)["'][^>]*>/
    for (let s of scriptMatches) {
      let match = srcReg.exec(s)
      if (match && match.length) {
        // handle src script
        // console.log(match[1])
      } else {
        scriptContents.push(s.replace(/<script[^>]*>|<\/script>/ig, ''))
      }
    }
    return {
      bodyContent,
      scriptContents
    };
  }

  /*
  * @param {HTMLElement} node
  * @return {Promise<void>}
   * */
  async function setupRef(node, data, itercount = 0) {
    console.log(itercount)
    if (itercount > 100) {
      log.warn('infinite loop')
      return
    }
    const ref = node.getAttribute('ref')
    node.setAttribute('tag', ref)
    node.removeAttribute('ref')
    const txt = await fetchFileWithCache(ref + ".html")
    let ast = extractBodyAndScript(txt)

    let div = document.createElement('div')
    div.innerHTML = ast.bodyContent

    handleSlots(node, div)
    // 
    node.innerHTML = div.innerHTML

    let resp = new Function("{vnode,data}", ast.scriptContents.join('\n'))({ vnode: node, data: data })

    for (let n of node.querySelectorAll("div[ref]")) {
      // 确保子元素先加载完
      await setupRef(n, resp?.data || {}, itercount + 1)
    }
  }

  function handleSlots(origin, template) {
    // handle slots
    let originSnap = { '': [] }
    let i = 0
    let child
    while (child = origin.children.item(i)) {
      i++
      let slotname = child.getAttribute ? child.getAttribute('slot') || '' : ''
      if (slotname !== '') {
        child.removeAttribute('slot')
        originSnap[slotname] = child
      } else {
        originSnap[''].push(child)
      }
    }

    app.b = originSnap
    let slots = template.querySelectorAll('slot')
    slots.forEach((slot) => {
      let slotname = slot.getAttribute('name') || ''
      let snap = originSnap[slotname]
      if (snap && snap.length !== 0) {
        if (slotname === '') {
          slot.replaceWith(...snap)
        } else {
          slot.replaceWith(snap)
        }
      } else {
        slot.replaceWith(...slot.childNodes)
      }
    })
  }

  document.addEventListener('DOMContentLoaded', () => {
    console.log('DOMContentLoaded');
    const node = document.getElementById('app');
    observer.observe(node, config);
    const sync = () => {
      let test = node.querySelectorAll("div[ref]")
      test.forEach(n => setupRef(n, app))
    }
    sync()
    // setInterval(sync, 10)
  });

})();