#include <assert.h>

#include <stdbool.h>

#include <stdlib.h>

#include "node.h"

#include "cmark.h"

#include "iterator.h"

static const int S_leaf_mask =

    (1 << CMARK_NODE_HTML_BLOCK) | (1 << CMARK_NODE_THEMATIC_BREAK) |

    (1 << CMARK_NODE_CODE_BLOCK) | (1 << CMARK_NODE_TEXT) |

    (1 << CMARK_NODE_SOFTBREAK) | (1 << CMARK_NODE_LINEBREAK) |

    (1 << CMARK_NODE_CODE) | (1 << CMARK_NODE_HTML_INLINE);

cmark_iter *cmark_iter_new(cmark_node *root) {

  if (root == NULL) {

    return NULL;

  }

  cmark_mem *mem = root->mem;

  cmark_iter *iter = (cmark_iter *)mem->calloc(1, sizeof(cmark_iter));

  iter->mem = mem;

  iter->root = root;

  iter->cur.ev_type = CMARK_EVENT_NONE;

  iter->cur.node = NULL;

  iter->next.ev_type = CMARK_EVENT_ENTER;

  iter->next.node = root;

  return iter;

}

void cmark_iter_free(cmark_iter *iter) { iter->mem->free(iter); }

static bool S_is_leaf(cmark_node *node) {

  return ((1 << node->type) & S_leaf_mask) != 0;

}

cmark_event_type cmark_iter_next(cmark_iter *iter) {

  cmark_event_type ev_type = iter->next.ev_type;

  cmark_node *node = iter->next.node;

  iter->cur.ev_type = ev_type;

  iter->cur.node = node;

  if (ev_type == CMARK_EVENT_DONE) {

    return ev_type;

  }

  /* roll forward to next item, setting both fields */

  if (ev_type == CMARK_EVENT_ENTER && !S_is_leaf(node)) {

    if (node->first_child == NULL) {

      /* stay on this node but exit */

      iter->next.ev_type = CMARK_EVENT_EXIT;

    } else {

      iter->next.ev_type = CMARK_EVENT_ENTER;

      iter->next.node = node->first_child;

    }

  } else if (node == iter->root) {

    /* don't move past root */

    iter->next.ev_type = CMARK_EVENT_DONE;

    iter->next.node = NULL;

  } else if (node->next) {

    iter->next.ev_type = CMARK_EVENT_ENTER;

    iter->next.node = node->next;

  } else if (node->parent) {

    iter->next.ev_type = CMARK_EVENT_EXIT;

    iter->next.node = node->parent;

  } else {

    assert(false);

    iter->next.ev_type = CMARK_EVENT_DONE;

    iter->next.node = NULL;

  }

  return ev_type;

}

void cmark_iter_reset(cmark_iter *iter, cmark_node *current,

                      cmark_event_type event_type) {

  iter->next.ev_type = event_type;

  iter->next.node = current;

  cmark_iter_next(iter);

}

cmark_node *cmark_iter_get_node(cmark_iter *iter) { return iter->cur.node; }

cmark_event_type cmark_iter_get_event_type(cmark_iter *iter) {

  return iter->cur.ev_type;

}

cmark_node *cmark_iter_get_root(cmark_iter *iter) { return iter->root; }

void cmark_consolidate_text_nodes(cmark_node *root) {

  if (root == NULL) {

    return;

  }

  cmark_iter *iter = cmark_iter_new(root);

  cmark_strbuf buf = CMARK_BUF_INIT(iter->mem);

  cmark_event_type ev_type;

  cmark_node *cur, *tmp, *next;

  while ((ev_type = cmark_iter_next(iter)) != CMARK_EVENT_DONE) {

    cur = cmark_iter_get_node(iter);

    if (ev_type == CMARK_EVENT_ENTER && cur->type == CMARK_NODE_TEXT &&

        cur->next && cur->next->type == CMARK_NODE_TEXT) {

      cmark_strbuf_clear(&buf);

      cmark_strbuf_put(&buf, cur->data, cur->len);

      tmp = cur->next;

      while (tmp && tmp->type == CMARK_NODE_TEXT) {

        cmark_iter_next(iter); // advance pointer

        cmark_strbuf_put(&buf, tmp->data, tmp->len);

        cur->end_column = tmp->end_column;

        next = tmp->next;

        cmark_node_free(tmp);

        tmp = next;

      }

      iter->mem->free(cur->data);

      cur->len = buf.size;

      cur->data = cmark_strbuf_detach(&buf);

    }

  }

  cmark_strbuf_free(&buf);

  cmark_iter_free(iter);

}