'use strict';

/**
 * @typedef {import('micromark-util-types').Code} Code
 * @typedef {import('micromark-util-types').InitialConstruct} InitialConstruct
 * @typedef {import('micromark-util-types').Initializer} Initializer
 * @typedef {import('micromark-util-types').Resolver} Resolver
 * @typedef {import('micromark-util-types').State} State
 * @typedef {import('micromark-util-types').TokenizeContext} TokenizeContext
 */

const resolver = {
  resolveAll: createResolver()
};
const string = initializeFactory('string');
const text = initializeFactory('text');

/**
 * @param {'string' | 'text'} field
 * @returns {InitialConstruct}
 */
function initializeFactory(field) {
  return {
    tokenize: initializeText,
    resolveAll: createResolver(
      field === 'text' ? resolveAllLineSuffixes : undefined
    )
  }

  /**
   * @this {TokenizeContext}
   * @type {Initializer}
   */
  function initializeText(effects) {
    const self = this;
    const constructs = this.parser.constructs[field];
    const text = effects.attempt(constructs, start, notText);
    return start

    /** @type {State} */
    function start(code) {
      return atBreak(code) ? text(code) : notText(code)
    }

    /** @type {State} */
    function notText(code) {
      if (code === null) {
        effects.consume(code);
        return
      }
      effects.enter('data');
      effects.consume(code);
      return data
    }

    /** @type {State} */
    function data(code) {
      if (atBreak(code)) {
        effects.exit('data');
        return text(code)
      }

      // Data.
      effects.consume(code);
      return data
    }

    /**
     * @param {Code} code
     * @returns {boolean}
     */
    function atBreak(code) {
      if (code === null) {
        return true
      }
      const list = constructs[code];
      let index = -1;
      if (list) {
        // Always populated by defaults.

        while (++index < list.length) {
          const item = list[index];
          if (!item.previous || item.previous.call(self, self.previous)) {
            return true
          }
        }
      }
      return false
    }
  }
}

/**
 * @param {Resolver | undefined} [extraResolver]
 * @returns {Resolver}
 */
function createResolver(extraResolver) {
  return resolveAllText

  /** @type {Resolver} */
  function resolveAllText(events, context) {
    let index = -1;
    /** @type {number | undefined} */
    let enter;

    // A rather boring computation (to merge adjacent `data` events) which
    // improves mm performance by 29%.
    while (++index <= events.length) {
      if (enter === undefined) {
        if (events[index] && events[index][1].type === 'data') {
          enter = index;
          index++;
        }
      } else if (!events[index] || events[index][1].type !== 'data') {
        // Don’t do anything if there is one data token.
        if (index !== enter + 2) {
          events[enter][1].end = events[index - 1][1].end;
          events.splice(enter + 2, index - enter - 2);
          index = enter + 2;
        }
        enter = undefined;
      }
    }
    return extraResolver ? extraResolver(events, context) : events
  }
}

/**
 * A rather ugly set of instructions which again looks at chunks in the input
 * stream.
 * The reason to do this here is that it is *much* faster to parse in reverse.
 * And that we can’t hook into `null` to split the line suffix before an EOF.
 * To do: figure out if we can make this into a clean utility, or even in core.
 * As it will be useful for GFMs literal autolink extension (and maybe even
 * tables?)
 *
 * @type {Resolver}
 */
function resolveAllLineSuffixes(events, context) {
  let eventIndex = 0; // Skip first.

  while (++eventIndex <= events.length) {
    if (
      (eventIndex === events.length ||
        events[eventIndex][1].type === 'lineEnding') &&
      events[eventIndex - 1][1].type === 'data'
    ) {
      const data = events[eventIndex - 1][1];
      const chunks = context.sliceStream(data);
      let index = chunks.length;
      let bufferIndex = -1;
      let size = 0;
      /** @type {boolean | undefined} */
      let tabs;
      while (index--) {
        const chunk = chunks[index];
        if (typeof chunk === 'string') {
          bufferIndex = chunk.length;
          while (chunk.charCodeAt(bufferIndex - 1) === 32) {
            size++;
            bufferIndex--;
          }
          if (bufferIndex) break
          bufferIndex = -1;
        }
        // Number
        else if (chunk === -2) {
          tabs = true;
          size++;
        } else if (chunk === -1) {
          // Empty
        } else {
          // Replacement character, exit.
          index++;
          break
        }
      }
      if (size) {
        const token = {
          type:
            eventIndex === events.length || tabs || size < 2
              ? 'lineSuffix'
              : 'hardBreakTrailing',
          start: {
            line: data.end.line,
            column: data.end.column - size,
            offset: data.end.offset - size,
            _index: data.start._index + index,
            _bufferIndex: index
              ? bufferIndex
              : data.start._bufferIndex + bufferIndex
          },
          end: Object.assign({}, data.end)
        };
        data.end = Object.assign({}, token.start);
        if (data.start.offset === data.end.offset) {
          Object.assign(data, token);
        } else {
          events.splice(
            eventIndex,
            0,
            ['enter', token, context],
            ['exit', token, context]
          );
          eventIndex += 2;
        }
      }
      eventIndex++;
    }
  }
  return events
}

exports.resolver = resolver;
exports.string = string;
exports.text = text;
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