// Shared editing operations for the desktop actor and Android content bridge.
export class InputEditor {
  constructor(win) { this.contentWindow=win; this.document=win.document; this.editing=false; }
  focus(element) { this.inputElement=element; }
  state() {
    const e=this.inputElement;
    const text=e.isContentEditable ? e.textContent : e.value;
    const selection=this.contentWindow.getSelection();
    let start=e.selectionStart ?? text.length, end=e.selectionEnd ?? start;
    if(e.isContentEditable && selection.rangeCount && e.contains(selection.anchorNode)) {
      const range=this.document.createRange();range.selectNodeContents(e);
      range.setEnd(selection.anchorNode,selection.anchorOffset);start=range.toString().length;
      range.setEnd(selection.focusNode,selection.focusOffset);end=range.toString().length;
      [start,end]=[Math.min(start,end),Math.max(start,end)];
    }
    return {type:e.isContentEditable?'contenteditable':e.localName,inputType:e.type || (e.classList.contains('recipient')?'tel':'text'),
      inputMode:e.inputMode || (e.classList.contains('recipient')?'tel':''),
      text:e.type==='password'?'':text,selectionStart:start,selectionEnd:end};
  }
  edit(p) {
    const e=this.inputElement,win=this.contentWindow;
    if(!e?.isConnected || this.document.hidden) throw Error('INPUT_CONTEXT_EXPIRED');
    this.editing=true;
    try {e.focus();} finally {this.editing=false;}
    // A touch can focus a new contenteditable while Gecko retains the previous
    // field's selection. execCommand follows that selection, not activeElement.
    if(e.isContentEditable) {
      const selection=win.getSelection();
      if(!e.contains(selection.anchorNode) || !e.contains(selection.focusNode)) {
        const range=this.document.createRange();
        range.selectNodeContents(e);range.collapse(false);
        selection.removeAllRanges();selection.addRange(range);
      }
    }
    if(p.operation==='key') {
      let key=typeof p.key==='object'?p.key.key:p.key;
      if(key===8 || key==='Backspace') this.document.execCommand('delete');
      else if(key===13 || key==='Enter') {
        const options={key:'Enter',code:'Enter',keyCode:13,charCode:13,which:13,bubbles:true,cancelable:true};
        const accepted=e.dispatchEvent(new win.KeyboardEvent('keydown',options)) && e.dispatchEvent(new win.KeyboardEvent('keypress',options));
        if(accepted && (e.isContentEditable || e.localName==='textarea')) this.document.execCommand('insertLineBreak');
        e.dispatchEvent(new win.KeyboardEvent('keyup',options));
      } else {
        const text=typeof key==='string'?key:String.fromCodePoint(p.charCode || key);
        if(text.length>16) throw Error('INVALID_VALUE');
        this.document.execCommand('insertText',false,text);
      }
    } else if(['selection','replace'].includes(p.operation)) {
      const state=this.state();
      const start=p.operation==='selection'?p.start:state.selectionStart+(p.offset||0);
      const length=p.length||0;
      if(!Number.isInteger(start)||!Number.isInteger(length)||start<0||length<0||start+length>(e.value ?? e.textContent).length) throw Error('INVALID_VALUE');
      if(e.isContentEditable) {
        const walker=this.document.createTreeWalker(e,win.NodeFilter.SHOW_TEXT);
        const points=[];let offset=0,node;
        while((node=walker.nextNode())) {points.push({node,start:offset,end:offset+node.length});offset+=node.length;}
        const point=index=>{const part=points.find(p=>index<=p.end);return part?[part.node,index-part.start]:[e,0];};
        const range=this.document.createRange();range.setStart(...point(start));range.setEnd(...point(start+length));
        win.getSelection().removeAllRanges();win.getSelection().addRange(range);
      } else e.setSelectionRange(start,start+length);
      if(p.operation==='replace') {
        if(typeof p.text!=='string'||p.text.length>4096) throw Error('INVALID_VALUE');
        this.document.execCommand('insertText',false,p.text);
      }
    } else throw Error('METHOD_NOT_SUPPORTED');
    return this.state();
  }
}