/*
   Copyright (c) 2014 Anton Titov.

   Copyright (c) 2014 pCloud Ltd.  All rights reserved.

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions
   are met: Redistributions of source code must retain the above
   copyright notice, this list of conditions and the following
   disclaimer.  Redistributions in binary form must reproduce the
   above copyright notice, this list of conditions and the following
   disclaimer in the documentation and/or other materials provided
   with the distribution.  Neither the name of pCloud Ltd nor the
   names of its contributors may be used to endorse or promote
   products derived from this software without specific prior written
   permission.

   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL pCloud
   Ltd BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
   OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
   USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
   DAMAGE.
*/

#include "pintervaltree.h"
#include "pmem.h"
#include "pdbg.h"

static psync_interval_tree_t *psync_interval_tree_new(uint64_t from,
                                                      uint64_t to) {
  psync_interval_tree_t *tree = pmem_malloc(PMEM_SUBSYS_OTHER, sizeof(psync_interval_tree_t));
  tree->from = from;
  tree->to = to;
  return psync_interval_tree_element(
      ptree_get_add_after(PSYNC_TREE_EMPTY, NULL, &tree->tree));
}

static psync_interval_tree_t *psync_interval_new(uint64_t from, uint64_t to) {
  psync_interval_tree_t *tree = pmem_malloc(PMEM_SUBSYS_OTHER, sizeof(psync_interval_tree_t));
  tree->from = from;
  tree->to = to;
  return tree;
}

static psync_interval_tree_t *
psync_interval_tree_consume_intervals(psync_interval_tree_t *tree,
                                      psync_interval_tree_t *e) {
  psync_interval_tree_t *next;
  while ((next = psync_interval_tree_get_next(e))) {
    if (next->from > e->to)
      break;
    psync_interval_tree_del(&tree, next);
    if (next->to >= e->to) {
      e->to = next->to;
      pmem_free(PMEM_SUBSYS_OTHER, next);
      break;
    }
    pmem_free(PMEM_SUBSYS_OTHER, next);
  }
  return tree;
}

static psync_interval_tree_t *
psync_interval_tree_get_add(psync_interval_tree_t *tree, uint64_t from,
                            uint64_t to) {
  //  pdbg_logf(D_NOTICE, "adding interval %lu %lu", from, to);
  pdbg_assert(to > from);
  if (unlikely(!tree))
    return psync_interval_tree_new(from, to);
  else {
    psync_interval_tree_t *e, *e2;
    e = tree;
    while (1) {
      pdbg_assert(from <= to);
      if (e->from <= from && e->to >= from) {
        if (e->to >= to)
          return tree;
        e->to = to;
        return psync_interval_tree_consume_intervals(tree, e);
      } else if (e->from > from) {
        if (e->tree.left)
          e = psync_interval_tree_element(e->tree.left);
        else if (e->from <= to && e->to >= to) {
          e->from = from;
          return tree;
        } else {
          e2 = psync_interval_new(from, to);
          return psync_interval_tree_consume_intervals(
              psync_interval_tree_element(
                  ptree_get_add_before(&tree->tree, &e->tree, &e2->tree)),
              e2);
        }
      } else {
        pdbg_assert(e->to < from);
        if (e->tree.right)
          e = psync_interval_tree_element(e->tree.right);
        else {
          e2 = psync_interval_new(from, to);
          return psync_interval_tree_consume_intervals(
              psync_interval_tree_element(
                  ptree_get_add_after(&tree->tree, &e->tree, &e2->tree)),
              e2);
        }
      }
    }
  }
}

void psync_interval_tree_add(psync_interval_tree_t **tree, uint64_t from,
                             uint64_t to) {
  *tree = psync_interval_tree_get_add(*tree, from, to);
}

void psync_interval_tree_remove(psync_interval_tree_t **tree, uint64_t from,
                                uint64_t to) {
  psync_interval_tree_t *tr, *ntr;
  tr = psync_interval_tree_first_interval_containing_or_after(*tree, from);
  while (tr) {
    if (tr->from < from && tr->to > to) {
      // the only case we have to split interval
      ptree_add_after((psync_tree **)tree, &tr->tree,
                           &psync_interval_new(to, tr->to)->tree);
      tr->to = from;
      break;
    }
    ntr = psync_interval_tree_get_next(tr);
    if (from <= tr->from && tr->from < to) {
      tr->from = to;
      if (tr->from >= tr->to)
        psync_interval_tree_del(tree, tr);
    } else if (tr->from < from)
      tr->to = from;
    else
      break;
    tr = ntr;
  }
}

static void free_interval_tree_node(psync_interval_tree_t *e) {
  pmem_free(PMEM_SUBSYS_OTHER, e);
}

void psync_interval_tree_free(psync_interval_tree_t *tree) {
  if (tree)
    ptree_for_each_element_call_safe(&tree->tree, psync_interval_tree_t, tree, free_interval_tree_node);
}

static psync_interval_tree_t *
psync_interval_tree_get_cut_end(psync_interval_tree_t *tree, uint64_t end) {
  psync_interval_tree_t *last, *prev;
  last = psync_interval_tree_get_last(tree);
  while (last && last->to > end) {
    if (last->from < end) {
      last->to = end;
      break;
    }
    prev = psync_interval_tree_get_prev(last);
    tree = psync_interval_tree_element(
        ptree_get_del(&tree->tree, &last->tree));
    pmem_free(PMEM_SUBSYS_OTHER, last);
    last = prev;
  }
  return tree;
}

void psync_interval_tree_cut_end(psync_interval_tree_t **tree, uint64_t end) {
  *tree = psync_interval_tree_get_cut_end(*tree, end);
}