#define PETSC_DESIRE_FEATURE_TEST_MACROS /* for strdup() */
#include <petsc/private/petscimpl.h>     /*I  "petscsys.h"  I*/

#if defined(PETSC_HAVE_YAML)
  #include <yaml.h> /* use external LibYAML */
#else
  #include <../src/sys/yaml/include/yaml.h>
#endif

PETSC_INTERN PetscErrorCode PetscOptionsSetValue_Private(PetscOptions, const char[], const char[], int *, PetscOptionSource);
PETSC_INTERN PetscErrorCode PetscOptionsInsertStringYAML_Private(PetscOptions, const char[], PetscOptionSource);

static MPI_Comm petsc_yaml_comm = MPI_COMM_NULL; /* only used for parallel error handling */

static inline MPI_Comm PetscYAMLGetComm(void)
{
  return PetscLikely(petsc_yaml_comm != MPI_COMM_NULL) ? petsc_yaml_comm : (petsc_yaml_comm = PETSC_COMM_SELF);
}

static inline MPI_Comm PetscYAMLSetComm(MPI_Comm comm)
{
  MPI_Comm prev   = PetscYAMLGetComm();
  petsc_yaml_comm = comm;
  return prev;
}

#define TAG(node) ((const char *)((node)->tag))
#define STR(node) ((const char *)((node)->data.scalar.value))
#define SEQ(node) ((node)->data.sequence.items)
#define MAP(node) ((node)->data.mapping.pairs)

static PetscErrorCode PetscParseLayerYAML(PetscOptions options, yaml_document_t *doc, yaml_node_t *node, PetscOptionSource source)
{
  MPI_Comm comm                        = PetscYAMLGetComm();
  char     name[PETSC_MAX_OPTION_NAME] = "", prefix[PETSC_MAX_OPTION_NAME] = "";

  PetscFunctionBegin;
  if (node->type == YAML_SCALAR_NODE && !STR(node)[0]) PetscFunctionReturn(PETSC_SUCCESS); /* empty */
  PetscCheck(node->type == YAML_MAPPING_NODE, comm, PETSC_ERR_SUP, "Unsupported YAML node type: expected mapping");
  for (yaml_node_pair_t *pair = MAP(node).start; pair < MAP(node).top; pair++) {
    yaml_node_t *keynode = yaml_document_get_node(doc, pair->key);
    yaml_node_t *valnode = yaml_document_get_node(doc, pair->value);
    PetscBool    isMergeKey, isDummyKey, isIncludeTag;

    PetscCheck(keynode, comm, PETSC_ERR_LIB, "Corrupt YAML document");
    PetscCheck(valnode, comm, PETSC_ERR_LIB, "Corrupt YAML document");
    PetscCheck(keynode->type == YAML_SCALAR_NODE, comm, PETSC_ERR_SUP, "Unsupported YAML node type: expected scalar");

    /* "<<" is the merge key: don't increment the prefix */
    PetscCall(PetscStrcmp(STR(keynode), "<<", &isMergeKey));
    if (isMergeKey) {
      if (valnode->type == YAML_SEQUENCE_NODE) {
        for (yaml_node_item_t *item = SEQ(valnode).start; item < SEQ(valnode).top; item++) {
          yaml_node_t *itemnode = yaml_document_get_node(doc, *item);
          PetscCheck(itemnode, comm, PETSC_ERR_LIB, "Corrupt YAML document");
          PetscCheck(itemnode->type == YAML_MAPPING_NODE, comm, PETSC_ERR_SUP, "Unsupported YAML node type: expected mapping");
          PetscCall(PetscParseLayerYAML(options, doc, itemnode, source));
        }
      } else if (valnode->type == YAML_MAPPING_NODE) {
        PetscCall(PetscParseLayerYAML(options, doc, valnode, source));
      } else SETERRQ(comm, PETSC_ERR_SUP, "Unsupported YAML node type: expected sequence or mapping");
      continue; /* to next pair */
    }

    /* "$$*" are treated as dummy keys, we use them for !include tags and to define anchors */
    PetscCall(PetscStrbeginswith(STR(keynode), "$$", &isDummyKey));
    if (isDummyKey) {
      PetscCall(PetscStrendswith(TAG(valnode), "!include", &isIncludeTag));
      if (isIncludeTag) { /* TODO: add proper support relative paths */
        PetscCall(PetscOptionsInsertFileYAML(comm, options, STR(valnode), PETSC_TRUE));
      }
      continue; /* to next pair */
    }

    if (valnode->type == YAML_SCALAR_NODE) {
      PetscCall(PetscSNPrintf(name, sizeof(name), "-%s", STR(keynode)));
      PetscCall(PetscOptionsSetValue_Private(options, name, STR(valnode), NULL, source));

    } else if (valnode->type == YAML_SEQUENCE_NODE) {
      PetscSegBuffer seg;
      char          *buf, *strlist;
      PetscBool      addSep = PETSC_FALSE;

      PetscCall(PetscSegBufferCreate(sizeof(char), PETSC_MAX_PATH_LEN, &seg));
      for (yaml_node_item_t *item = SEQ(valnode).start; item < SEQ(valnode).top; item++) {
        yaml_node_t *itemnode = yaml_document_get_node(doc, *item);
        const char  *itemstr  = NULL;
        size_t       itemlen;

        PetscCheck(itemnode, comm, PETSC_ERR_LIB, "Corrupt YAML document");

        if (itemnode->type == YAML_SCALAR_NODE) {
          itemstr = STR(itemnode);

        } else if (itemnode->type == YAML_MAPPING_NODE) {
          yaml_node_pair_t *kvn = itemnode->data.mapping.pairs.start;
          yaml_node_pair_t *top = itemnode->data.mapping.pairs.top;

          PetscCheck(top - kvn <= 1, comm, PETSC_ERR_SUP, "Unsupported YAML node value: expected a single key:value pair");
          if (top - kvn > 0) {
            yaml_node_t *kn = yaml_document_get_node(doc, kvn->key);
            yaml_node_t *vn = yaml_document_get_node(doc, kvn->value);

            PetscCheck(kn, comm, PETSC_ERR_LIB, "Corrupt YAML document");
            PetscCheck(vn, comm, PETSC_ERR_LIB, "Corrupt YAML document");
            PetscCheck(kn->type == YAML_SCALAR_NODE, comm, PETSC_ERR_SUP, "Unsupported YAML node type: expected scalar");

            PetscCall(PetscStrcmp(STR(kn), "<<", &isMergeKey));
            PetscCheck(!isMergeKey, comm, PETSC_ERR_SUP, "Unsupported YAML node value: merge key '<<' not supported here");

            PetscCall(PetscStrbeginswith(STR(kn), "$$", &isDummyKey));
            if (isDummyKey) continue;
            itemstr = STR(kn);
          }

          PetscCall(PetscSNPrintf(prefix, sizeof(prefix), "%s_", STR(keynode)));
          PetscCall(PetscOptionsPrefixPush(options, prefix));
          PetscCall(PetscParseLayerYAML(options, doc, itemnode, source));
          PetscCall(PetscOptionsPrefixPop(options));

        } else SETERRQ(comm, PETSC_ERR_SUP, "Unsupported YAML node type: expected scalar or mapping");

        PetscCall(PetscStrlen(itemstr, &itemlen));
        if (itemlen) {
          if (addSep) {
            PetscCall(PetscSegBufferGet(seg, 1, &buf));
            PetscCall(PetscArraycpy(buf, ",", 1));
          }
          PetscCall(PetscSegBufferGet(seg, itemlen, &buf));
          PetscCall(PetscArraycpy(buf, itemstr, itemlen));
          addSep = PETSC_TRUE;
        }
      }
      PetscCall(PetscSegBufferGet(seg, 1, &buf));
      PetscCall(PetscArrayzero(buf, 1));
      PetscCall(PetscSegBufferExtractAlloc(seg, &strlist));
      PetscCall(PetscSegBufferDestroy(&seg));

      PetscCall(PetscSNPrintf(name, sizeof(name), "-%s", STR(keynode)));
      PetscCall(PetscOptionsSetValue_Private(options, name, strlist, NULL, source));
      PetscCall(PetscFree(strlist));

    } else if (valnode->type == YAML_MAPPING_NODE) {
      PetscCall(PetscSNPrintf(prefix, sizeof(prefix), "%s_", STR(keynode)));
      PetscCall(PetscOptionsPrefixPush(options, prefix));
      PetscCall(PetscParseLayerYAML(options, doc, valnode, source));
      PetscCall(PetscOptionsPrefixPop(options));

    } else SETERRQ(comm, PETSC_ERR_SUP, "Unsupported YAML node type: expected scalar, sequence or mapping");
  }
  PetscFunctionReturn(PETSC_SUCCESS);
}

PetscErrorCode PetscOptionsInsertStringYAML_Private(PetscOptions options, const char in_str[], PetscOptionSource source)
{
  MPI_Comm        comm = PetscYAMLGetComm();
  yaml_parser_t   parser;
  yaml_document_t doc;
  yaml_node_t    *root;
  int             err;

  PetscFunctionBegin;
  if (!in_str) in_str = "";
  err = !yaml_parser_initialize(&parser);
  PetscCheck(!err, comm, PETSC_ERR_LIB, "YAML parser initialization error");
  yaml_parser_set_input_string(&parser, (const unsigned char *)in_str, strlen(in_str));
  do {
    err = !yaml_parser_load(&parser, &doc);
    PetscCheck(!err, comm, PETSC_ERR_LIB, "YAML parser loading error");
    root = yaml_document_get_root_node(&doc);
    if (root) PetscCall(PetscParseLayerYAML(options, &doc, root, source));
    yaml_document_delete(&doc);
  } while (root);
  yaml_parser_delete(&parser);
  PetscFunctionReturn(PETSC_SUCCESS);
}
/*@C
  PetscOptionsInsertStringYAML - Inserts YAML-formatted options into the options database from a string

  Logically Collective

  Input Parameters:
+ options - options database, use `NULL` for default global database
- in_str  - YAML-formatted string options

  Level: intermediate

.seealso: `PetscOptionsSetValue()`, `PetscOptionsView()`, `PetscOptionsHasName()`, `PetscOptionsGetInt()`,
          `PetscOptionsGetReal()`, `PetscOptionsGetString()`, `PetscOptionsGetIntArray()`, `PetscOptionsBool()`,
          `PetscOptionsName()`, `PetscOptionsBegin()`, `PetscOptionsEnd()`, `PetscOptionsHeadBegin()`,
          `PetscOptionsStringArray()`, `PetscOptionsRealArray()`, `PetscOptionsScalar()`,
          `PetscOptionsBoolGroupBegin()`, `PetscOptionsBoolGroup()`, `PetscOptionsBoolGroupEnd()`,
          `PetscOptionsFList()`, `PetscOptionsEList()`, `PetscOptionsInsertFile()`, `PetscOptionsInsertFileYAML()`
@*/
PetscErrorCode PetscOptionsInsertStringYAML(PetscOptions options, const char in_str[])
{
  PetscFunctionBegin;
  PetscCall(PetscOptionsInsertStringYAML_Private(options, in_str, PETSC_OPT_CODE));
  PetscFunctionReturn(PETSC_SUCCESS);
}

/*@C
  PetscOptionsInsertFileYAML - Insert a YAML-formatted file in the options database

  Collective

  Input Parameters:
+ comm    - the processes that will share the options (usually `PETSC_COMM_WORLD`)
. options - options database, use `NULL` for default global database
. file    - name of file
- require - if `PETSC_TRUE` will generate an error if the file does not exist

  Level: intermediate

  Notes:
  PETSc will generate an error condition that stops the program if a YAML error
  is detected, hence the user should check that the YAML file is valid before
  supplying it, for instance at <http://www.yamllint.com> .

  Uses `PetscOptionsInsertStringYAML()`.

.seealso: `PetscOptionsSetValue()`, `PetscOptionsView()`, `PetscOptionsHasName()`, `PetscOptionsGetInt()`,
          `PetscOptionsGetReal()`, `PetscOptionsGetString()`, `PetscOptionsGetIntArray()`, `PetscOptionsBool()`,
          `PetscOptionsName()`, `PetscOptionsBegin()`, `PetscOptionsEnd()`, `PetscOptionsHeadBegin()`,
          `PetscOptionsStringArray()`, `PetscOptionsRealArray()`, `PetscOptionsScalar()`,
          `PetscOptionsBoolGroupBegin()`, `PetscOptionsBoolGroup()`, `PetscOptionsBoolGroupEnd()`,
          `PetscOptionsFList()`, `PetscOptionsEList()`, `PetscOptionsInsertFile()`, `PetscOptionsInsertStringYAML()`
@*/
PetscErrorCode PetscOptionsInsertFileYAML(MPI_Comm comm, PetscOptions options, const char file[], PetscBool require)
{
  int         yamlLength = -1;
  char       *yamlString = NULL;
  MPI_Comm    prev;
  PetscMPIInt rank;

  PetscFunctionBegin;
  PetscCallMPI(MPI_Comm_rank(comm, &rank));
  if (rank == 0) {
    char   fpath[PETSC_MAX_PATH_LEN];
    char   fname[PETSC_MAX_PATH_LEN];
    FILE  *fd;
    size_t rd;

    PetscCall(PetscStrreplace(PETSC_COMM_SELF, file, fpath, sizeof(fpath)));
    PetscCall(PetscFixFilename(fpath, fname));

    fd = fopen(fname, "r");
    if (fd) {
      fseek(fd, 0, SEEK_END);
      yamlLength = (int)ftell(fd);
      fseek(fd, 0, SEEK_SET);
      PetscCheck(yamlLength >= 0, PETSC_COMM_SELF, PETSC_ERR_FILE_OPEN, "Unable to query size of YAML file: %s", fname);
      PetscCall(PetscMalloc1(yamlLength + 1, &yamlString));
      rd = fread(yamlString, 1, (size_t)yamlLength, fd);
      PetscCheck(rd == (size_t)yamlLength, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read entire YAML file: %s", fname);
      yamlString[yamlLength] = 0;
      fclose(fd);
    }
  }

  PetscCallMPI(MPI_Bcast(&yamlLength, 1, MPI_INT, 0, comm));
  PetscCheck(!require || yamlLength >= 0, comm, PETSC_ERR_FILE_OPEN, "Unable to open YAML option file: %s", file);
  if (yamlLength < 0) PetscFunctionReturn(PETSC_SUCCESS);

  if (rank) PetscCall(PetscMalloc1(yamlLength + 1, &yamlString));
  PetscCallMPI(MPI_Bcast(yamlString, yamlLength + 1, MPI_CHAR, 0, comm));

  prev = PetscYAMLSetComm(comm);
  PetscCall(PetscOptionsInsertStringYAML_Private(options, yamlString, PETSC_OPT_FILE));
  (void)PetscYAMLSetComm(prev);

  PetscCall(PetscFree(yamlString));
  PetscFunctionReturn(PETSC_SUCCESS);
}

#if !defined(PETSC_HAVE_YAML)

  /*
#if !defined(PETSC_HAVE_STRDUP)
#define strdup(s) (char*)memcpy(malloc(strlen(s)+1),s,strlen(s)+1)
#endif
*/

  /* Embed LibYAML in this compilation unit */
  #include <../src/sys/yaml/src/api.c>
  #include <../src/sys/yaml/src/loader.c>
  #include <../src/sys/yaml/src/parser.c>
  #include <../src/sys/yaml/src/reader.c>

  /*
  Avoid compiler warnings like
    scanner.c, line 3181: warning: integer conversion resulted in a change of sign
                          *(string.pointer++) = '\xC2';

  Once yaml fixes them, we can remove the pragmas
*/
  #pragma GCC diagnostic push
  #pragma GCC diagnostic ignored "-Wsign-conversion"
  #include <../src/sys/yaml/src/scanner.c>
  #pragma GCC diagnostic pop

/* Silence a few unused-function warnings */
static PETSC_UNUSED void petsc_yaml_unused(void)
{
  (void)yaml_parser_scan;
  (void)yaml_document_get_node;
  (void)yaml_parser_set_encoding;
  (void)yaml_parser_set_input;
  (void)yaml_parser_set_input_file;
}

#endif
