/**
 * Copyright 2018 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *     http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// @ts-nocheck //TODO

/* MAIN */

// This is just a slightly customized version of htm: dynamic props are marked as such, indexes of dynamics are remembered //TODO

const MODE_SLASH = 0;
const MODE_TEXT = 1;
const MODE_WHITESPACE = 2;
const MODE_TAGNAME = 3;
const MODE_COMMENT = 4;
const MODE_PROP_SET = 5;
const MODE_PROP_APPEND = 6;

const htm = function(statics) {
  const fields = arguments;
  const h = this;

  let mode = MODE_TEXT;
  let buffer = '';
  let quote = '';
  let current = [0];
  let char, propName;

  const commit = (field?) => {
    if (mode === MODE_TEXT && (field || (buffer = buffer.replace(/^\s*\n\s*|\s*\n\s*$/g,'')))) {
      current.push(field ? fields[field] : buffer);
    }
    else if (mode === MODE_TAGNAME && (field || buffer)) {
        current[1] = field ? fields[field] : buffer;
      mode = MODE_WHITESPACE;
    }
    else if (mode === MODE_WHITESPACE && buffer === '...' && field) {
        current[2] = Object.assign(current[2] || {}, fields[field]);
    }
    else if (mode === MODE_WHITESPACE && buffer && !field) {
        (current[2] = current[2] || {})[buffer] = true;
    }
    else if (mode >= MODE_PROP_SET) {
      const prefix = field ? '$' : '';
      if (mode === MODE_PROP_SET) {
        (current[2] = current[2] || {})[prefix + propName] = field ? buffer ? (buffer + fields[field]) : fields[field] : buffer;
        mode = MODE_PROP_APPEND;
      }
      else if (field || buffer) {
        current[2][prefix + propName] += field ? buffer + fields[field] : buffer;
      }
    }

    buffer = '';
  };

  for (let i=0; i<statics.length; i++) {
    if (i) {
      if (mode === MODE_TEXT) {
        commit();
      }
      commit(i);
    }

    for (let j=0; j<statics[i].length;j++) {
      char = statics[i][j];

      if (mode === MODE_TEXT) {
        if (char === '<') {
          // commit buffer
          commit();
            current = [current, '', null];
          mode = MODE_TAGNAME;
        }
        else {
          buffer += char;
        }
      }
      else if (mode === MODE_COMMENT) {
        // Ignore everything until the last three characters are '-', '-' and '>'
        if (buffer === '--' && char === '>') {
          mode = MODE_TEXT;
          buffer = '';
        }
        else {
          buffer = char + buffer[0];
        }
      }
      else if (quote) {
        if (char === quote) {
          quote = '';
        }
        else {
          buffer += char;
        }
      }
      else if (char === '"' || char === "'") {
        quote = char;
      }
      else if (char === '>') {
        commit();
        mode = MODE_TEXT;
      }
      else if (!mode) {
        // Ignore everything until the tag ends
      }
      else if (char === '=') {
        mode = MODE_PROP_SET;
        propName = buffer;
        buffer = '';
      }
      else if (char === '/' && (mode < MODE_PROP_SET || statics[i][j+1] === '>')) {
        commit();
        if (mode === MODE_TAGNAME) {
          current = current[0];
        }
        mode = current;
          (current = current[0]).push(h.apply(null, mode.slice(1)));
        mode = MODE_SLASH;
      }
      else if (char === ' ' || char === '\t' || char === '\n' || char === '\r') {
        // <a disabled>
        commit();
        mode = MODE_WHITESPACE;
      }
      else {
        buffer += char;
      }

      if (mode === MODE_TAGNAME && buffer === '!--') {
        mode = MODE_COMMENT;
        current = current[0];
      }
    }
  }
  commit();

  return current.length > 2 ? current.slice(1) : current[1];
};

/* EXPORT */

export default htm;