/*
  Copyright (c) 2007 Stefan Kurtz <kurtz@zbh.uni-hamburg.de>
  Copyright (c) 2007 Center for Bioinformatics, University of Hamburg

  Permission to use, copy, modify, and distribute this software for any
  purpose with or without fee is hereby granted, provided that the above
  copyright notice and this permission notice appear in all copies.

  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

#include "core/assert_api.h"
#include "core/arraydef.h"
#include "core/chardef.h"
#include "core/divmodmul.h"
#include "core/format64.h"
#include "core/intbits.h"
#include "core/encseq.h"
#include "core/ma_api.h"
#include "merger-trie.h"

#define MTRIE_ISLEAF(NODE) ((NODE)->firstchild == NULL)
#ifdef WITHTRIEIDENT
#ifdef WITHTRIESHOW
#define SHOWNODERELATIONS(NODE)\
        shownoderelations(__LINE__,#NODE,NODE)
#else
#define SHOWNODERELATIONS(NODE) /* Nothing */
#endif
#else
#define SHOWNODERELATIONS(NODE) /* Nothing */
#endif

#define SETFIRSTCHILD(NODE,VALUE)\
        (NODE)->firstchild = VALUE;\
        if ((VALUE) != NULL)\
        {\
          (VALUE)->parent = NODE;\
        }

#define SETFIRSTCHILDNULL(NODE)\
        (NODE)->firstchild = NULL

typedef struct
{
  Mergertrienode *previous,
           *current;
} Nodepair;

static GtUchar getfirstedgechar(const Mergertrierep *trierep,
                              const Mergertrienode *node,
                              GtUword prevdepth)
{
  Encseqreadinfo *eri = trierep->encseqreadinfo + node->suffixinfo.idx;

  if (MTRIE_ISLEAF(node) &&
      node->suffixinfo.startpos + prevdepth >=
      gt_encseq_total_length(eri->encseqptr))
  {
    return (GtUchar) SEPARATOR;
  }
  return gt_encseq_get_encoded_char(eri->encseqptr, /* Random access */
                        node->suffixinfo.startpos + prevdepth,
                        eri->readmode);
}

static int mtrie_comparecharacters(GtUchar cc1,unsigned int idx1,
                                   GtUchar cc2,unsigned int idx2)
{
  if (ISSPECIAL(cc1))
  {
    if (ISSPECIAL(cc2))
    {
      if (idx1 <= idx2)
      {
        return -1;  /* cc1 < cc2 */
      } else
      {
        return 1;  /* cc1 > cc2 */
      }
    } else
    {
      return 1; /* cc1 > cc2 */
    }
  } else
  {
    if (ISSPECIAL(cc2))
    {
      return -1;  /* cc1 < cc2 */
    } else
    {
      if (cc1 < cc2)
      {
        return -1;  /* cc1 < cc2 */
      } else
      {
        if (cc1 > cc2)
        {
          return 1;  /* cc1 > cc2 */
        } else
        {
          return 0; /* cc1 == cc2 */
        }
      }
    }
  }
}

#ifdef WITHTRIEIDENT
static void showmergertrie2(const Mergertrierep *trierep,
                            const GtUchar *characters,
                            unsigned int level,
                            const Mergertrienode *node)
{
  GtUchar cc = 0;
  GtUword pos, endpos;
  Mergertrienode *current;

  for (current = node->firstchild;
       current != NULL;
       current = current->rightsibling)
  {
    printf("%*.*s",(int) (6 * level),(int) (6 * level)," ");
    if (MTRIE_ISLEAF(current))
    {
      endpos = gt_encseq_total_length(
                                 trierep->encseqtable[current->suffixinfo.idx]);
    } else
    {
      endpos = current->suffixinfo.startpos + current->depth;
    }
    for (pos = current->suffixinfo.startpos + node->depth;
         pos < endpos; pos++)
    {
      cc = gt_encseq_get_encoded_char( /* just for testing */
              trierep->enseqreadinfo[current->suffixinfo.idx].encseqptr,
              pos,
              trierep->enseqreadinfo[current->suffixinfo.idx].readmode);
      if (ISSPECIAL(cc))
      {
        printf("#\n");
        break;
      }
      printf("%c",characters[(int) cc]);
    }
    if (MTRIE_ISLEAF(current))
    {
      if (!ISSPECIAL(cc))
      {
        printf("~\n");
      }
    } else
    {
      printf(" d="GT_WU",i=" Formatuint64_t "\n",
            current->depth,
            PRINTuint64_tcast(current->suffixinfo.ident));
      showmergertrie2(trierep,characters,level+1,current);
    }
  }
}

void mergertrie_show(const Mergertrierep *trierep,
                     const GtUchar *characters)
{
  if (trierep->root != NULL)
  {
    showmergertrie2(trierep,characters,0,trierep->root);
  }
}

/*
   Check the following:
   (1) for each branching node there exist at least 2 DONE
   (2) for each branching node the list of successors is strictly ordered
       according to the first character of the edge label DONE
   (3) there are no empty edge labels DONE
   (4) there are \(n+1\) leaves and for each leaf there is exactly one
       incoming edge DONE
*/

static void checkmergertrie2(Mergertrierep *trierep,
                             Mergertrienode *node,
                             Mergertrienode *father,
                             Bitsequence *leafused,
                             unsigned int *numberofbitsset)
{
  Mergertrienode *current, *previous;

  if (MTRIE_ISLEAF(node))
  {
    GtUword start = node->suffixinfo.startpos;
#ifndef NDEBUG
    if (ISIBITSET(leafused,start))
    {
      fprintf(stderr,"leaf "GT_WU" already found\n",start);
      exit(GT_EXIT_PROGRAMMING_ERROR);
    }
#endif
    SETIBIT(leafused,start);
    (*numberofbitsset)++;
  } else
  {
    gt_assert(node->depth == 0 || node->firstchild->rightsibling != NULL);
    if (father != NULL)
    {
      gt_assert(!MTRIE_ISLEAF(father));
#ifndef NDEBUG
      if (father->depth >= node->depth)
      {
        fprintf(stderr,"father.depth = "GT_WU" >= "GT_WU" = node.depth\n",
                       father->depth,
                       node->depth);
        exit(GT_EXIT_PROGRAMMING_ERROR);
      }
#endif
    }
    previous = NULL;
    for (current = node->firstchild; current != NULL;
        current = current->rightsibling)
    {
#ifndef NDEBUG
      if (previous != NULL)
      {
        if (mtrie_comparecharacters(
              getfirstedgechar(trierep,previous,node->depth),
              previous->suffixinfo.idx,
              getfirstedgechar(trierep,current,node->depth),
              current->suffixinfo.idx) >= 0)
        {
          fprintf(stderr,"nodes not correctly ordered\n");
          exit(GT_EXIT_PROGRAMMING_ERROR);
        }
      }
#endif
      checkmergertrie2(trierep,current,node,leafused,numberofbitsset);
      previous = current;
    }
  }
}

void mergertrie_check(Mergertrierep *trierep,unsigned int numberofleaves,
                      unsigned int maxleafnum,GtError *err)
{
  gt_error_check(err);
  if (trierep->root != NULL)
  {
    Bitsequence *leafused;
    unsigned int numberofbitsset = 0;

    INITBITTAB(leafused,maxleafnum+1);
    checkmergertrie2(trierep,trierep->root,NULL,leafused,&numberofbitsset);
#ifndef NDEBUG
    if (numberofbitsset != numberofleaves)
    {
      fprintf(stderr,"numberofbitsset = %u != %u = numberofleaves\n",
                      numberofbitsset,
                      numberofleaves);
      exit(GT_EXIT_PROGRAMMING_ERROR);
    }
#endif
    gt_free(leafused);
  }
}

#ifdef WITHTRIESHOW
static void shownode(const Mergertrienode *node)
{
  if (node == NULL)
  {
    printf("NULL");
  } else
  {
    printf("%s " Formatuint64_t,MTRIE_ISLEAF(node) ? "leaf" : "branch",
                   PRINTuint64_tcast(node->suffixinfo.ident));
  }
}

static void showsimplenoderelations(const Mergertrienode *node)
{
  shownode(node);
  printf(".firstchild=");
  shownode(node->firstchild);
  printf("; ");
  shownode(node);
  printf(".rightsibling=");
  shownode(node->rightsibling);
  printf("\n");
}

static void shownoderelations(int line,char *nodestring,
                              const Mergertrienode *node)
{
  printf("l. %d: %s: ",line,nodestring);
  showsimplenoderelations(node);
}

void mergertrie_showallnoderelations(const Mergertrienode *node)
{
  Mergertrienode *tmp;

  showsimplenoderelations(node);
  for (tmp = node->firstchild; tmp != NULL; tmp = tmp->rightsibling)
  {
    if (tmp->firstchild == NULL)
    {
      showsimplenoderelations(tmp);
    } else
    {
      mergertrie_showallnoderelations(tmp);
    }
  }
}
#endif
#endif

static Mergertrienode *newMergertrienode(Mergertrierep *trierep)
{
#ifdef WITHTRIEIDENT
#ifdef WITHTRIESHOW
  printf("# available trie nodes: %u; ",
          trierep->allocatedMergertrienode - trierep->nextfreeMergertrienode);
  printf("unused trie nodes: %u\n",trierep->nextunused);
#endif
#endif
  if (trierep->nextfreeMergertrienode >= trierep->allocatedMergertrienode)
  {
    gt_assert(trierep->nextunused > 0);
    trierep->nextunused--;
    return trierep->unusedMergertrienodes[trierep->nextunused];
  }
  return trierep->nodetable + trierep->nextfreeMergertrienode++;
}

static Mergertrienode *mtrie_makenewleaf(Mergertrierep *trierep,
                                   Suffixinfo *suffixinfo)
{
  Mergertrienode *newleaf;

#ifdef WITHTRIEIDENT
#ifdef WITHTRIESHOW
  printf("makenewleaf(" Formatuint64_t ")\n",
         PRINTuint64_tcast(suffixinfo->ident));
#endif
#endif
  newleaf = newMergertrienode(trierep);
  newleaf->suffixinfo = *suffixinfo;
  SETFIRSTCHILDNULL(newleaf);
  newleaf->rightsibling = NULL;
  SHOWNODERELATIONS(newleaf);
  return newleaf;
}

static Mergertrienode *mtrie_makeroot(Mergertrierep *trierep,
                                      Suffixinfo *suffixinfo)
{
  Mergertrienode *root, *newleaf;

#ifdef WITHTRIEIDENT
#ifdef WITHTRIESHOW
  printf("makeroot(" Formatuint64_t ")\n",PRINTuint64_tcast(suffixinfo->ident));
#endif
#endif
  root = newMergertrienode(trierep);
  root->parent = NULL;
  root->suffixinfo = *suffixinfo;
  root->depth = 0;
  root->rightsibling = NULL;
  newleaf = mtrie_makenewleaf(trierep,suffixinfo);
  SETFIRSTCHILD(root,newleaf);
  SHOWNODERELATIONS(root);
  return root;
}

static void makesuccs(Mergertrienode *newbranch,Mergertrienode *first,
                      Mergertrienode *second)
{
  second->rightsibling = NULL;
  first->rightsibling = second;
  SETFIRSTCHILD(newbranch,first);
  SHOWNODERELATIONS(second);
  SHOWNODERELATIONS(first);
  SHOWNODERELATIONS(newbranch);
}

static Mergertrienode *mtrie_makenewbranch(Mergertrierep *trierep,
                                     Suffixinfo *suffixinfo,
                                     GtUword currentdepth,
                                     Mergertrienode *oldnode)
{
  Mergertrienode *newbranch, *newleaf;
  GtUchar cc1, cc2;
  Encseqreadinfo *eri = trierep->encseqreadinfo + suffixinfo->idx;

#ifdef WITHTRIEIDENT
#ifdef WITHTRIESHOW
  printf("makenewbranch(ident=" Formatuint64_t ")\n",
          PRINTuint64_tcast(suffixinfo->ident));
#endif
#endif
  newbranch = newMergertrienode(trierep);
  newbranch->suffixinfo = *suffixinfo;
  newbranch->rightsibling = oldnode->rightsibling;
  cc1 = getfirstedgechar(trierep,oldnode,currentdepth);
  if (suffixinfo->startpos + currentdepth >=
      gt_encseq_total_length(eri->encseqptr))
  {
    cc2 = (GtUchar) SEPARATOR;
  } else
  {
    cc2 = gt_encseq_get_encoded_char(eri->encseqptr,
                         suffixinfo->startpos + currentdepth,
                         eri->readmode);
  }
  newleaf = mtrie_makenewleaf(trierep,suffixinfo);
  if (mtrie_comparecharacters(cc1,oldnode->suffixinfo.idx,
                        cc2,suffixinfo->idx) <= 0)
  {
    makesuccs(newbranch,oldnode,newleaf);
  } else
  {
    makesuccs(newbranch,newleaf,oldnode);
  }
  newbranch->depth = currentdepth;
  return newbranch;
}

static GtUword getlcp(const GtEncseq *encseq1,
                            GtReadmode readmode1,
                            GtUword start1, GtUword end1,
                            const GtEncseq *encseq2,
                            GtReadmode readmode2,
                            GtUword start2, GtUword end2)
{
  GtUword i1, i2;
  GtUchar cc1;

  for (i1=start1, i2=start2; i1 <= end1 && i2 <= end2; i1++, i2++)
  {
    cc1 = gt_encseq_get_encoded_char(/*XXX*/ encseq1,i1,readmode1);
    if (cc1 != gt_encseq_get_encoded_char(/*XXX*/ encseq2,i2,readmode2)
          || ISSPECIAL(cc1))
    {
      break;
    }
  }
  return i1 - start1;
}

static bool hassuccessor(const Mergertrierep *trierep,
                         Nodepair *np,
                         GtUword prevdepth,
                         const Mergertrienode *node,
                         GtUchar cc2,
                         unsigned int idx2)
{
  GtUchar cc1;
  int cmpresult;

  for (np->previous = NULL, np->current = node->firstchild;
      np->current != NULL;
      np->current = np->current->rightsibling)
  {
    cc1 = getfirstedgechar(trierep,np->current,prevdepth);
    cmpresult = mtrie_comparecharacters(cc1,np->current->suffixinfo.idx,cc2,
                                        idx2);
    if (cmpresult == 1)
    {
      return false;
    }
    if (cmpresult == 0)
    {
      return true;
    }
    np->previous = np->current;
  }
  return false;
}

void gt_mergertrie_insertsuffix(Mergertrierep *trierep,
                             Mergertrienode *node,
                             Suffixinfo *suffixinfo)
{
  if (trierep->root == NULL)
  {
    trierep->root = mtrie_makeroot(trierep,suffixinfo);
  } else
  {
    GtUword currentdepth, lcpvalue, totallength;
    Mergertrienode *currentnode, *newleaf, *newbranch, *succ;
    Nodepair np;
    GtUchar cc;
    Encseqreadinfo *eri = trierep->encseqreadinfo + suffixinfo->idx;

    gt_assert(!MTRIE_ISLEAF(node));
    currentnode = node;
    currentdepth = node->depth;
    totallength = gt_encseq_total_length(eri->encseqptr);
    while (true)
    {
      if (suffixinfo->startpos + currentdepth >= totallength)
      {
        cc = (GtUchar) SEPARATOR;
      } else
      {
        /* Random access */
        cc = gt_encseq_get_encoded_char(eri->encseqptr,
                                            suffixinfo->startpos + currentdepth,
                                            eri->readmode);
      }
      gt_assert(currentnode != NULL);
      gt_assert(!MTRIE_ISLEAF(currentnode));
      if (!hassuccessor(trierep,&np,currentdepth,currentnode,cc,
                        suffixinfo->idx))
      {
        newleaf = mtrie_makenewleaf(trierep,suffixinfo);
        newleaf->rightsibling = np.current;
        SHOWNODERELATIONS(newleaf);
        if (np.previous == NULL)
        {
          SETFIRSTCHILD(currentnode,newleaf);
          SHOWNODERELATIONS(currentnode);
        } else
        {
          np.previous->rightsibling = newleaf;
          SHOWNODERELATIONS(np.previous);
        }
        return;
      }
      succ = np.current;
      if MTRIE_ISLEAF(succ)
      {
        lcpvalue = getlcp(eri->encseqptr,
                          eri->readmode,
                          suffixinfo->startpos + currentdepth + 1,
                          gt_encseq_total_length(eri->encseqptr) - 1,
                          trierep->encseqreadinfo[succ->suffixinfo.idx].
                                encseqptr,
                          trierep->encseqreadinfo[succ->suffixinfo.idx].
                                readmode,
                          succ->suffixinfo.startpos + currentdepth + 1,
                          gt_encseq_total_length(
                              trierep->encseqreadinfo[succ->suffixinfo.idx].
                                        encseqptr) - 1);
        newbranch = mtrie_makenewbranch(trierep,
                                  suffixinfo,
                                  currentdepth + lcpvalue + 1,
                                  succ);
        if (np.previous == NULL)
        {
          SETFIRSTCHILD(currentnode,newbranch);
          SHOWNODERELATIONS(currentnode);
        } else
        {
          np.previous->rightsibling = newbranch;
          SHOWNODERELATIONS(np.previous);
        }
        return;
      }
      lcpvalue = getlcp(eri->encseqptr,
                        eri->readmode,
                        suffixinfo->startpos + currentdepth + 1,
                        gt_encseq_total_length(eri->encseqptr) - 1,
                        trierep->encseqreadinfo[succ->suffixinfo.idx].encseqptr,
                        trierep->encseqreadinfo[succ->suffixinfo.idx].readmode,
                        succ->suffixinfo.startpos + currentdepth + 1,
                        succ->suffixinfo.startpos + succ->depth - 1);
      if (currentdepth + lcpvalue + 1 < succ->depth)
      {
        newbranch = mtrie_makenewbranch(trierep,
                                  suffixinfo,
                                  currentdepth + lcpvalue + 1,
                                  succ);
        if (np.previous == NULL)
        {
          SETFIRSTCHILD(currentnode,newbranch);
          SHOWNODERELATIONS(currentnode);
        } else
        {
          np.previous->rightsibling = newbranch;
          SHOWNODERELATIONS(np.previous);
        }
        return;
      }
      currentnode = succ;
      currentdepth = currentnode->depth;
    }
  }
}

Mergertrienode *gt_mergertrie_findsmallestnode(const Mergertrierep *trierep)
{
  Mergertrienode *node;

  gt_assert(trierep->root != NULL);
  for (node = trierep->root; node->firstchild != NULL; node = node->firstchild)
    /* Nothing */ ;
  return node;
}

void gt_mergertrie_deletesmallestpath(Mergertrienode *smallest,
                                   Mergertrierep *trierep)
{
  Mergertrienode *father, *son;

  for (son = smallest; son->parent != NULL; son = son->parent)
  {
    father = son->parent;
    if (son->firstchild == NULL)
    {
      SETFIRSTCHILD(father,son->rightsibling);
      SHOWNODERELATIONS(father);
      son->rightsibling = NULL;
    } else
    {
      if (son->firstchild->rightsibling != NULL)
      {
        break;
      }
      son->firstchild->rightsibling = father->firstchild->rightsibling;
      SETFIRSTCHILD(father,son->firstchild);
      SHOWNODERELATIONS(father);
      son->rightsibling = NULL;
      SETFIRSTCHILDNULL(son);
    }
#ifdef WITHTRIEIDENT
#ifdef WITHTRIESHOW
    printf("delete %s " Formatuint64_t "\n",
             MTRIE_ISLEAF(son) ? "leaf" : "branch",
             PRINTuint64_tcast(son->suffixinfo.ident));
#endif
#endif
    trierep->unusedMergertrienodes[trierep->nextunused++] = son;
  }
  if (trierep->root->firstchild == NULL)
  {
    trierep->unusedMergertrienodes[trierep->nextunused++] = trierep->root;
    trierep->root = NULL;
  }
}

void gt_mergertrie_initnodetable(Mergertrierep *trierep,
                              GtUword numofsuffixes,
                              unsigned int numofindexes)
{
  trierep->numofindexes = numofindexes;
  trierep->allocatedMergertrienode
    = (unsigned int) GT_MULT2(numofsuffixes + 1) + 1;
  trierep->nodetable = gt_malloc(sizeof *trierep->nodetable
                                 * trierep->allocatedMergertrienode);
  trierep->nextfreeMergertrienode = 0;
  trierep->root = NULL;
  trierep->nextunused = 0;
  trierep->unusedMergertrienodes
    = gt_malloc(sizeof *trierep->unusedMergertrienodes
                * trierep->allocatedMergertrienode);
}

void gt_mergertrie_delete(Mergertrierep *trierep)
{
  if (trierep != NULL)
  {
    gt_free(trierep->nodetable);
    gt_free(trierep->unusedMergertrienodes);
    gt_free(trierep->encseqreadinfo);
    trierep->encseqreadinfo = NULL;
  }
}
