// Row 154 (#1648, Q168): the editor view. A ProseMirror EditorView over model.mjs's schema, a toolbar, a
// link bar, and the keymap. Everything is built with DOM calls (createElement, textContent, setAttribute);
// there is no string-to-markup sink in this file.
import { EditorState } from 'prosemirror-state';
import { EditorView } from 'prosemirror-view';
import { history, undo, redo } from 'prosemirror-history';
import { keymap } from 'prosemirror-keymap';
import { baseKeymap, toggleMark, setBlockType, wrapIn, chainCommands, exitCode } from 'prosemirror-commands';
import { wrapInList, splitListItem, liftListItem, sinkListItem } from 'prosemirror-schema-list';
import { InputRule, inputRules, textblockTypeInputRule, wrappingInputRule, undoInputRule } from 'prosemirror-inputrules';
import { schema, parse, serialise, linkTarget } from './model.mjs';

const { paragraph, heading, code_block, blockquote, bullet_list, ordered_list, list_item, hard_break, horizontal_rule } = schema.nodes;
const { strong, em, code, link } = schema.marks;

const inCode = state => state.selection.$from.parent.type.spec.code;

function markActive(state, type) {
  const { from, $from, to, empty } = state.selection;
  return empty ? !!type.isInSet(state.storedMarks || $from.marks()) : state.doc.rangeHasMark(from, to, type);
}

// -------------------------------------------------------------------------------- commands
const insertBreak = chainCommands(exitCode, (state, dispatch) => {
  if (dispatch) dispatch(state.tr.replaceSelectionWith(hard_break.create()).scrollIntoView());
  return true;
});
const insertRule = (state, dispatch) => {
  if (dispatch) dispatch(state.tr.replaceSelectionWith(horizontal_rule.create()).scrollIntoView());
  return true;
};
const heading_ = level => setBlockType(heading, { level });

// The link bar: set the target on the selection, or remove the link. The gate decides; a refused target
// changes nothing and the bar says so.
function applyLink(view, raw) {
  const { state } = view, { from, to, empty } = state.selection;
  if (raw === '') {
    if (!empty) view.dispatch(state.tr.removeMark(from, to, link));
    return true;
  }
  const href = linkTarget(raw);
  if (!href || empty) return false;
  view.dispatch(state.tr.removeMark(from, to, link).addMark(from, to, link.create({ href })));
  return true;
}

// -------------------------------------------------------------------------------- input rules
const rules = [
  textblockTypeInputRule(/^(#{1,6})\s$/, heading, m => ({ level: m[1].length })),
  textblockTypeInputRule(/^```$/, code_block),
  wrappingInputRule(/^\s*>\s$/, blockquote),
  wrappingInputRule(/^\s*([-+*])\s$/, bullet_list),
  wrappingInputRule(/^(\d+)\.\s$/, ordered_list, m => ({ order: +m[1] }), (m, node) => node.childCount + node.attrs.order === +m[1]),
  new InputRule(/^(?:---|___)$/, (state, match, start, end) => state.tr.replaceRangeWith(start, end, horizontal_rule.create()).scrollIntoView()),
];

// -------------------------------------------------------------------------------- toolbar
const BUTTONS = [
  ['strong', 'B', 'Bold (Ctrl+B)', toggleMark(strong), s => markActive(s, strong)],
  ['em', 'I', 'Italic (Ctrl+I)', toggleMark(em), s => markActive(s, em)],
  ['code', '</>', 'Code (Ctrl+`)', toggleMark(code), s => markActive(s, code)],
  ['link', 'Link', 'Link (Ctrl+K)', null, s => markActive(s, link)],
  ['h1', 'H1', 'Heading 1', heading_(1), s => s.selection.$from.parent.hasMarkup(heading, { level: 1 })],
  ['h2', 'H2', 'Heading 2', heading_(2), s => s.selection.$from.parent.hasMarkup(heading, { level: 2 })],
  ['h3', 'H3', 'Heading 3', heading_(3), s => s.selection.$from.parent.hasMarkup(heading, { level: 3 })],
  ['p', 'Text', 'Paragraph', setBlockType(paragraph), s => s.selection.$from.parent.type === paragraph],
  ['ul', '• List', 'Bulleted list', wrapInList(bullet_list), () => false],
  ['ol', '1. List', 'Numbered list', wrapInList(ordered_list), () => false],
  ['quote', '❝', 'Quote', wrapIn(blockquote), () => false],
  ['codeblock', '{ }', 'Code block', setBlockType(code_block), s => s.selection.$from.parent.type === code_block],
  ['rule', '―', 'Horizontal rule', insertRule, () => false],
  ['undo', 'Undo', 'Undo (Ctrl+Z)', undo, () => false],
  ['redo', 'Redo', 'Redo (Ctrl+Y)', redo, () => false],
];

function toolbar(getView, openLink) {
  const bar = document.createElement('div');
  bar.className = 'ed-toolbar';
  bar.setAttribute('role', 'toolbar');
  bar.setAttribute('aria-label', 'Formatting');
  const items = BUTTONS.map(([id, label, title, command, active]) => {
    const b = document.createElement('button');
    b.type = 'button';
    b.className = 'ed-btn';
    b.dataset.cmd = id;
    b.title = title;
    b.setAttribute('aria-label', title);
    b.textContent = label;
    // mousedown keeps the editor selection; the command runs on click
    b.addEventListener('mousedown', e => e.preventDefault());
    b.addEventListener('click', () => {
      const view = getView();
      if (!view || view.editable === false) return;
      if (id === 'link') openLink(); else command(view.state, view.dispatch, view);
      if (id !== 'link') view.focus();
    });
    bar.appendChild(b);
    return { b, command, active };
  });
  const sync = state => {
    for (const { b, command, active } of items) {
      b.classList.toggle('on', !!active(state));
      b.disabled = command ? !command(state) : false;
      b.setAttribute('aria-pressed', b.classList.contains('on') ? 'true' : 'false');
    }
  };
  return { bar, sync };
}

function linkBar(getView) {
  const form = document.createElement('form');
  form.className = 'ed-linkbar';
  form.hidden = true;
  const input = document.createElement('input');
  input.type = 'text';
  input.className = 'ed-link-input';
  input.setAttribute('aria-label', 'Link target (http, https or a relative path)');
  input.placeholder = 'https://… or a relative path; empty removes the link';
  input.autocomplete = 'off';
  input.spellcheck = false;
  const ok = document.createElement('button');
  ok.type = 'submit';
  ok.className = 'ed-btn';
  ok.textContent = 'Set';
  const cancel = document.createElement('button');
  cancel.type = 'button';
  cancel.className = 'ed-btn';
  cancel.textContent = 'Cancel';
  const note = document.createElement('span');
  note.className = 'ed-link-note';
  note.setAttribute('role', 'status');
  form.append(input, ok, cancel, note);
  const close = () => { form.hidden = true; note.textContent = ''; getView()?.focus(); };
  cancel.addEventListener('click', close);
  input.addEventListener('keydown', e => { if (e.key === 'Escape') { e.preventDefault(); close(); } });
  form.addEventListener('submit', e => {
    e.preventDefault();
    e.stopPropagation(); // the Console's own submit handler is for the save form
    const view = getView();
    if (!view) return;
    if (applyLink(view, input.value.trim())) close();
    else note.textContent = 'That target is not allowed. Use http, https or a relative path, and select the text first.';
  });
  const open = () => {
    const view = getView();
    if (!view) return;
    const { from, to, empty, $from } = view.state.selection;
    if (empty && !markActive(view.state, link)) { form.hidden = false; input.value = ''; note.textContent = 'Select the text to link first.'; return; }
    const at = view.state.doc.rangeHasMark(from, to, link) ? view.state.doc.nodeAt(from)?.marks.find(m => m.type === link) : null;
    input.value = at ? at.attrs.href : '';
    note.textContent = '';
    form.hidden = false;
    input.focus();
    input.select();
  };
  return { form, open };
}

// -------------------------------------------------------------------------------- the editor
/// mount(host, {text, editable, onChange}) -> { text(), setText(text), destroy(), focus(), view }
export function mount(host, { text = '', editable = true, onChange = () => {} } = {}) {
  let view = null;
  const getView = () => view;
  const wrap = document.createElement('div');
  wrap.className = 'ed-wrap';
  const link_ = linkBar(getView);
  const tools = toolbar(getView, link_.open);
  const surface = document.createElement('div');
  surface.className = 'ed-surface';
  if (editable) wrap.append(tools.bar, link_.form);
  wrap.appendChild(surface);
  host.appendChild(wrap);

  const keys = {
    'Mod-z': undo, 'Mod-y': redo, 'Shift-Mod-z': redo, Backspace: undoInputRule,
    'Mod-b': toggleMark(strong), 'Mod-i': toggleMark(em), 'Mod-`': toggleMark(code),
    'Mod-k': () => { link_.open(); return true; },
    'Shift-Enter': insertBreak, 'Mod-Enter': insertBreak,
    Enter: splitListItem(list_item),
    Tab: sinkListItem(list_item), 'Shift-Tab': liftListItem(list_item),
  };
  const fresh = src => EditorState.create({
    schema, doc: parse(src),
    plugins: [inputRules({ rules }), keymap(keys), keymap(baseKeymap), history()],
  });

  view = new EditorView(surface, {
    state: fresh(text),
    editable: () => editable,
    attributes: { 'aria-label': 'Document', 'aria-multiline': 'true', role: 'textbox', spellcheck: 'true', 'data-field': 'doc-visual' },
    dispatchTransaction(tr) {
      const next = view.state.apply(tr);
      view.updateState(next);
      tools.sync(next);
      if (tr.docChanged) onChange();
    },
    // Pasted and dropped content goes through the schema's parse rules only; nothing here adds to them.
  });
  tools.sync(view.state);

  return {
    view,
    text: () => serialise(view.state.doc),
    setText(src) { view.updateState(fresh(src)); tools.sync(view.state); },
    focus: () => view.focus(),
    destroy() { view.destroy(); wrap.remove(); },
  };
}