/*
 * v2dom.ts
 * Copyright (C) 2024 veypi <i@veypi.com>
 * 2024-10-23 15:54
 * Distributed under terms of the GPL license.
 */

import proxy from "./proxy"


interface buildOpts<T> {
  id?: string
  typ?: string
  class?: string
  attrs?: attrs
  style?: string
  innerHtml?: string
  onclick?: any
  children?: childTyp<T>[]
  updator?: (p: HTMLElement) => void
  vbind?: [Object, string]
}

const typs = ['div', 'img', 'span', 'p', 'a', 'input']

type iterChild<T> = [T[], (d: T) => HTMLElement]
type childTyp<T> = HTMLElement | iterChild<T>
type computedFn = () => any
type attrs = { [key: string]: string | number | computedFn }
export default <T>(opts: buildOpts<T> | string, inner?: string | computedFn | childTyp<T>[], attrs?: attrs) => {
  if (typeof opts === 'string') {
    if (typs.indexOf(opts) >= 0) {
      opts = { typ: opts }
    } else {
      opts = { class: opts }
    }
  }
  let dom = document.createElement(opts.typ || 'div')
  if (inner) {
    if (typeof inner == 'string') {
      opts.innerHtml = inner
    } else if (typeof inner == 'function') {
      addListener(dom, () => {
        let res = inner()
        if (typeof res === 'string') {
          dom.innerHTML = res
        } else {
          dom.innerHTML = ''
          dom.appendChild(inner())
        }
      })
    } else {
      opts.children = inner
    }
  }
  if (attrs) {
    opts.attrs = attrs
  }
  if (opts.id) {
    dom.id = opts.id
  }
  if (opts.class) {
    dom.classList.add(...opts.class.split(' '))
  }
  if (opts.innerHtml) {
    dom.innerHTML = opts.innerHtml
  }
  if (opts.attrs) {
    for (let a in opts.attrs) {
      let attr = opts.attrs[a]
      if (typeof attr === 'function') {
        addListener(dom, () => {
          dom.setAttribute(a, attr())
        })
      } else {
        dom.setAttribute(a, String(attr))
      }
    }
  }
  if (opts.onclick) {
    dom.onclick = opts.onclick
  }
  if (opts.children) {
    let tmpID = ''
    for (let c of opts.children) {
      if (Object.prototype.toString.call(c) === '[object Array]') {
        const iterID = proxy.generateUniqueId()
        const iterLast = tmpID
        addListener(dom, () => {
          c = c as iterChild<T>
          let itemIDs: string[] = []
          for (let i = 0; i < c[0].length; i++) {
            let line = c[0][i]
            //@ts-ignore
            let itemID = line[proxy.DataID] || ''
            let nextID = ''
            if (i < c[0].length - 1) {
              //@ts-ignore
              nextID = c[0][i + 1][proxy.DataID] || ''
            }
            itemIDs.push(itemID)
            let inserted = -2
            let subdom: HTMLElement | null = null
            let beforeChild: HTMLElement | null = null
            for (let childID = 0; childID < dom.children.length; childID++) {
              let child = dom.children[childID]
              // console.log(`${inserted} ${childID} ${itemID} ${nextID}`)
              if (child.getAttribute('vbind-iter') === iterID) {
                if (child.getAttribute('vbind-proxy') === itemID) {
                  inserted = childID
                  subdom = child as HTMLElement
                } else if (child.getAttribute('vbind-proxy') === nextID && nextID != '') {
                  // 用于交换位置
                  if (inserted != childID - 1) {
                    beforeChild = child as HTMLElement
                  }
                }
              } else if (child.getAttribute('vbind-iterlast') === iterID) {
                if (inserted == -2) {
                  beforeChild = child as HTMLElement
                }
                // 找到第一个不是这个循环块的dom元素时退出
                break
              }
            }
            if (inserted == -2) {
              subdom = c[1](line)
              subdom.setAttribute('vbind-proxy', itemID)
              subdom.setAttribute('vbind-iter', iterID)
              if (iterLast != '') {
                subdom.setAttribute('vbind-iterlast', iterLast)
              }
              if (beforeChild) {
                dom.insertBefore(subdom, beforeChild)
                // console.log(`${iterID} insert new`, subdom)
              } else {
                // console.log(`${iterID} append new`, subdom)
                dom.appendChild(subdom)
              }
            } else if (beforeChild) {
              // console.log(`${iterID} insert old`, subdom)
              dom.insertBefore(subdom!, beforeChild)
            } else {
              // console.log(`${iterID} none`, subdom)
            }
          }
          for (let child of dom.children) {
            if (child.getAttribute('vbind-iter') === iterID && itemIDs.indexOf(child.getAttribute('vbind-proxy') || '') == -1) {
              dom.removeChild(child)
            }
          }
        })
        tmpID = iterID
      } else {
        c = c as HTMLElement
        if (tmpID != '') {
          c.setAttribute('vbind-iterlast', tmpID)
        }
        dom.appendChild(c)
      }
    }
  }
  if (opts.style) {
    const regex = /([a-zA-Z-]+)\s*:\s*([^;]+);?/g;
    let match: any
    while ((match = regex.exec(opts.style)) !== null) {
      const key = match[1].trim();
      const value = match[2].trim();
      dom.style.setProperty(key, value)
    }
  }
  dom.setAttribute('voa', '1')
  if (opts.updator) {
    addListener(dom, () => {
      opts.updator!(dom)
    })
  }
  if (opts.vbind && opts.typ === 'input') {
    dom.setAttribute('value', Reflect.get(opts.vbind[0], opts.vbind[1]))
    dom.addEventListener('input', (e) => {
      // @ts-ignore
      Reflect.set(opts.vbind[0], opts.vbind[1], e.target.value)
    })
  }
  return dom
}


function addListener(dom: HTMLElement, fn: () => void) {
  let fns = dom.getAttribute('vbind-fns')
  let fnid = proxy.Listen(fn)
  if (fns) {
    fns += ',' + fnid
  } else {
    fns = String(fnid)
  }
  dom.setAttribute('vbind-fns', fns)
}