/*
  Copyright 2011-2020 David Robillard <d@drobilla.net>

  Permission to use, copy, modify, and/or 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.

  THIS 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 "node.h"

#include "base64.h"
#include "string_utils.h"
#include "system.h"

#include "serd/serd.h"

#include <assert.h>
#include <float.h>
#include <math.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifdef _WIN32
#  ifndef isnan
#    define isnan(x) _isnan(x)
#  endif
#  ifndef isinf
#    define isinf(x) (!_finite(x))
#  endif
#endif

static const size_t serd_node_align = 2 * sizeof(uint64_t);

static const SerdNodeFlags meta_mask = (SERD_HAS_DATATYPE | SERD_HAS_LANGUAGE);

static SerdNode*
serd_new_from_uri(SerdURIView uri, SerdURIView base);

static size_t
serd_uri_string_length(const SerdURIView* const uri)
{
  size_t len = uri->path_prefix.len;

#define ADD_LEN(field, n_delims)     \
  if ((field).len) {                 \
    len += (field).len + (n_delims); \
  }

  ADD_LEN(uri->path, 1)      // + possible leading `/'
  ADD_LEN(uri->scheme, 1)    // + trailing `:'
  ADD_LEN(uri->authority, 2) // + leading `//'
  ADD_LEN(uri->query, 1)     // + leading `?'
  ADD_LEN(uri->fragment, 1)  // + leading `#'

  return len + 2; // + 2 for authority `//'
}

static size_t
string_sink(const void* const buf, const size_t len, void* const stream)
{
  char** ptr = (char**)stream;
  memcpy(*ptr, buf, len);
  *ptr += len;
  return len;
}

static size_t
serd_node_pad_size(const size_t n_bytes)
{
  const size_t pad = sizeof(SerdNode) - (n_bytes + 2) % sizeof(SerdNode);
  return n_bytes + 2 + pad;
}

static const SerdNode*
serd_node_meta_c(const SerdNode* const node)
{
  return node + 1 + (serd_node_pad_size(node->length) / sizeof(SerdNode));
}

static const SerdNode*
serd_node_maybe_get_meta_c(const SerdNode* const node)
{
  return (node->flags & meta_mask) ? serd_node_meta_c(node) : NULL;
}

static SERD_PURE_FUNC
size_t
serd_node_total_size(const SerdNode* const node)
{
  return node ? (sizeof(SerdNode) + serd_node_pad_size(node->length) +
                 serd_node_total_size(serd_node_maybe_get_meta_c(node)))
              : 0;
}

SerdNode*
serd_node_malloc(const size_t        length,
                 const SerdNodeFlags flags,
                 const SerdNodeType  type)
{
  const size_t size = sizeof(SerdNode) + serd_node_pad_size(length);
  SerdNode*    node = (SerdNode*)serd_calloc_aligned(serd_node_align, size);

  node->length = 0;
  node->flags  = flags;
  node->type   = type;

  assert((intptr_t)node % serd_node_align == 0);
  return node;
}

void
serd_node_set(SerdNode** const dst, const SerdNode* const src)
{
  if (!src) {
    serd_free_aligned(*dst);
    *dst = NULL;
    return;
  }

  const size_t size = serd_node_total_size(src);
  if (!*dst || serd_node_total_size(*dst) < size) {
    serd_free_aligned(*dst);
    *dst = (SerdNode*)serd_calloc_aligned(serd_node_align, size);
  }

  assert(*dst);
  memcpy(*dst, src, size);
}

SerdNode*
serd_new_simple_node(const SerdNodeType type, const SerdStringView str)
{
  if (type != SERD_BLANK && type != SERD_CURIE && type != SERD_URI) {
    return NULL;
  }

  SerdNodeFlags flags  = 0;
  const size_t  length = str.buf ? serd_strlen(str.buf, &flags) : 0;
  SerdNode*     node   = serd_node_malloc(length, flags, type);

  if (node) {
    if (str.buf) {
      memcpy(serd_node_buffer(node), str.buf, length);
    }

    node->length = length;
  }

  return node;
}

SerdNode*
serd_new_string(const SerdStringView str)
{
  SerdNodeFlags flags  = 0;
  const size_t  length = serd_substrlen(str.buf, str.len, &flags);
  SerdNode*     node   = serd_node_malloc(length, flags, SERD_LITERAL);

  memcpy(serd_node_buffer(node), str.buf, str.len);
  node->length = length;

  return node;
}

SerdNode*
serd_new_literal(const SerdStringView str,
                 const SerdStringView datatype_uri,
                 const SerdStringView lang)
{
  SerdNodeFlags flags  = 0;
  const size_t  length = serd_substrlen(str.buf, str.len, &flags);
  const size_t  len    = serd_node_pad_size(length);

  SerdNode* node = NULL;
  if (lang.len) {
    const size_t total_len = len + sizeof(SerdNode) + lang.len;

    node = serd_node_malloc(total_len, flags | SERD_HAS_LANGUAGE, SERD_LITERAL);
    node->length = length;
    memcpy(serd_node_buffer(node), str.buf, length);

    SerdNode* lang_node = node + 1 + (len / sizeof(SerdNode));
    lang_node->type     = SERD_LITERAL;
    lang_node->length   = lang.len;
    memcpy(serd_node_buffer(lang_node), lang.buf, lang.len);

  } else if (datatype_uri.len) {
    const size_t total_len = len + sizeof(SerdNode) + datatype_uri.len;

    node = serd_node_malloc(total_len, flags | SERD_HAS_DATATYPE, SERD_LITERAL);
    node->length = length;
    memcpy(serd_node_buffer(node), str.buf, length);

    SerdNode* datatype_node = node + 1 + (len / sizeof(SerdNode));
    datatype_node->type     = SERD_URI;
    datatype_node->length   = datatype_uri.len;
    memcpy(serd_node_buffer(datatype_node), datatype_uri.buf, datatype_uri.len);

  } else {
    node = serd_node_malloc(length, flags, SERD_LITERAL);
    memcpy(serd_node_buffer(node), str.buf, length);
    node->length = length;
  }

  return node;
}

SerdNode*
serd_new_blank(const SerdStringView str)
{
  return serd_new_simple_node(SERD_BLANK, str);
}

SerdNode*
serd_new_curie(const SerdStringView str)
{
  return serd_new_simple_node(SERD_CURIE, str);
}

SerdNode*
serd_node_copy(const SerdNode* node)
{
  if (!node) {
    return NULL;
  }

  const size_t size = serd_node_total_size(node);
  SerdNode*    copy = (SerdNode*)serd_calloc_aligned(serd_node_align, size);
  memcpy(copy, node, size);
  return copy;
}

bool
serd_node_equals(const SerdNode* const a, const SerdNode* const b)
{
  if (a == b) {
    return true;
  }

  if (!a || !b || a->length != b->length || a->flags != b->flags ||
      a->type != b->type) {
    return false;
  }

  const size_t length = a->length;
  if (!!memcmp(serd_node_string(a), serd_node_string(b), length)) {
    return false;
  }

  const SerdNodeFlags flags = a->flags;
  if (flags & meta_mask) {
    const SerdNode* const am = serd_node_meta_c(a);
    const SerdNode* const bm = serd_node_meta_c(b);

    return am->length == bm->length && am->type == bm->type &&
           !memcmp(serd_node_string(am), serd_node_string(bm), am->length);
  }

  return true;
}

SerdNode*
serd_new_uri(const SerdStringView str)
{
  return serd_new_simple_node(SERD_URI, str);
}

SerdNode*
serd_new_parsed_uri(const SerdURIView uri)
{
  const size_t    len        = serd_uri_string_length(&uri);
  SerdNode* const node       = serd_node_malloc(len, 0, SERD_URI);
  char*           ptr        = serd_node_buffer(node);
  const size_t    actual_len = serd_write_uri(uri, string_sink, &ptr);

  serd_node_buffer(node)[actual_len] = '\0';
  node->length                       = actual_len;

  return node;
}

static SerdNode*
serd_new_from_uri(const SerdURIView uri, const SerdURIView base)
{
  const SerdURIView abs_uri    = serd_resolve_uri(uri, base);
  const size_t      len        = serd_uri_string_length(&abs_uri);
  SerdNode*         node       = serd_node_malloc(len, 0, SERD_URI);
  char*             ptr        = serd_node_buffer(node);
  const size_t      actual_len = serd_write_uri(abs_uri, string_sink, &ptr);

  serd_node_buffer(node)[actual_len] = '\0';
  node->length                       = actual_len;

  return node;
}

SerdNode*
serd_new_resolved_uri(const SerdStringView string, const SerdURIView base)
{
  const SerdURIView uri    = serd_parse_uri(string.buf);
  SerdNode* const   result = serd_new_from_uri(uri, base);

  if (!serd_uri_string_has_scheme(serd_node_string(result))) {
    serd_node_free(result);
    return NULL;
  }

  return result;
}

static bool
is_uri_path_char(const char c)
{
  if (is_alpha(c) || is_digit(c)) {
    return true;
  }

  switch (c) {
  // unreserved:
  case '-':
  case '.':
  case '_':
  case '~':
  case ':':

  case '@': // pchar
  case '/': // separator

  // sub-delimiters:
  case '!':
  case '$':
  case '&':
  case '\'':
  case '(':
  case ')':
  case '*':
  case '+':
  case ',':
  case ';':
  case '=':
    return true;
  default:
    return false;
  }
}

SerdNode*
serd_new_file_uri(const SerdStringView path, const SerdStringView hostname)
{
  const bool is_windows = is_windows_path(path.buf);
  size_t     uri_len    = 0;
  char*      uri        = NULL;

  if (path.buf[0] == '/' || is_windows) {
    uri_len = strlen("file://") + hostname.len + is_windows;
    uri     = (char*)calloc(uri_len + 1, 1);

    memcpy(uri, "file://", 7);

    if (hostname.len) {
      memcpy(uri + 7, hostname.buf, hostname.len + 1);
    }

    if (is_windows) {
      uri[7 + hostname.len] = '/';
    }
  }

  SerdBuffer buffer = {uri, uri_len};
  for (size_t i = 0; i < path.len; ++i) {
    if (is_windows && path.buf[i] == '\\') {
      serd_buffer_sink("/", 1, &buffer);
    } else if (path.buf[i] == '%') {
      serd_buffer_sink("%%", 2, &buffer);
    } else if (is_uri_path_char(path.buf[i])) {
      serd_buffer_sink(path.buf + i, 1, &buffer);
    } else {
      char escape_str[10] = {'%', 0, 0, 0, 0, 0, 0, 0, 0, 0};
      snprintf(
        escape_str + 1, sizeof(escape_str) - 1, "%X", (unsigned)path.buf[i]);
      serd_buffer_sink(escape_str, 3, &buffer);
    }
  }
  serd_buffer_sink_finish(&buffer);

  SerdNode* node =
    serd_new_uri(SERD_SUBSTRING((const char*)buffer.buf, buffer.len - 1));

  free(buffer.buf);
  return node;
}

static unsigned
serd_digits(const double abs)
{
  const double lg = ceil(log10(floor(abs) + 1.0));
  return lg < 1.0 ? 1U : (unsigned)lg;
}

SerdNode*
serd_new_decimal(const double d, const unsigned frac_digits)
{
  if (isnan(d) || isinf(d)) {
    return NULL;
  }

  const double    abs_d      = fabs(d);
  const unsigned  int_digits = serd_digits(abs_d);
  const size_t    len        = int_digits + frac_digits + 3;
  SerdNode* const node       = serd_node_malloc(len, 0, SERD_LITERAL);
  char* const     buf        = serd_node_buffer(node);
  const double    int_part   = floor(abs_d);

  // Point s to decimal point location
  char* s = buf + int_digits;
  if (d < 0.0) {
    *buf = '-';
    ++s;
  }

  // Write integer part (right to left)
  char*    t   = s - 1;
  uint64_t dec = (uint64_t)int_part;
  do {
    *t-- = (char)('0' + dec % 10);
  } while ((dec /= 10) > 0);

  *s++ = '.';

  // Write fractional part (right to left)
  double frac_part = fabs(d - int_part);
  if (frac_part < DBL_EPSILON) {
    *s++         = '0';
    node->length = (size_t)(s - buf);
  } else {
    uint64_t frac = (uint64_t)llround(frac_part * pow(10.0, (int)frac_digits));
    s += frac_digits - 1;
    unsigned i = 0;

    // Skip trailing zeros
    for (; i < frac_digits - 1 && !(frac % 10); ++i, --s, frac /= 10) {
    }

    node->length = (size_t)(s - buf) + 1u;

    // Write digits from last trailing zero to decimal point
    for (; i < frac_digits; ++i) {
      *s-- = (char)('0' + (frac % 10));
      frac /= 10;
    }
  }

  return node;
}

SerdNode*
serd_new_integer(const int64_t i)
{
  uint64_t       abs_i  = (i < 0) ? -i : i;
  const unsigned digits = serd_digits((double)abs_i);
  SerdNode*      node   = serd_node_malloc(digits + 2, 0, SERD_LITERAL);
  char*          buf    = serd_node_buffer(node);

  // Point s to the end
  char* s = buf + digits - 1;
  if (i < 0) {
    *buf = '-';
    ++s;
  }

  node->length = (size_t)(s - buf) + 1u;

  // Write integer part (right to left)
  do {
    *s-- = (char)('0' + (abs_i % 10));
  } while ((abs_i /= 10) > 0);

  return node;
}

SerdNode*
serd_new_blob(const void* const buf, const size_t size, const bool wrap_lines)
{
  if (!buf || !size) {
    return NULL;
  }

  const size_t len  = serd_base64_get_length(size, wrap_lines);
  SerdNode*    node = serd_node_malloc(len + 1, 0, SERD_LITERAL);
  uint8_t*     str  = (uint8_t*)serd_node_buffer(node);

  if (serd_base64_encode(str, buf, size, wrap_lines)) {
    node->flags |= SERD_HAS_NEWLINE;
  }

  node->length = len;
  return node;
}

SerdNodeType
serd_node_type(const SerdNode* const node)
{
  return node->type;
}

const char*
serd_node_string(const SerdNode* const node)
{
  return (const char*)(node + 1);
}

size_t
serd_node_length(const SerdNode* const node)
{
  return node->length;
}

SerdStringView
serd_node_string_view(const SerdNode* const node)
{
  const SerdStringView r = {(const char*)(node + 1), node->length};

  return r;
}

SerdURIView
serd_node_uri_view(const SerdNode* const node)
{
  return (node->type == SERD_URI) ? serd_parse_uri(serd_node_string(node))
                                  : SERD_URI_NULL;
}

SERD_PURE_FUNC
static const SerdNode*
serd_node_meta_node(const SerdNode* node)
{
  const size_t len = serd_node_pad_size(node->length);
  return node + 1 + (len / sizeof(SerdNode));
}

const SerdNode*
serd_node_datatype(const SerdNode* const node)
{
  if (!node || !(node->flags & SERD_HAS_DATATYPE)) {
    return NULL;
  }

  const SerdNode* const datatype = serd_node_meta_node(node);
  assert(datatype->type == SERD_URI || datatype->type == SERD_CURIE);
  return datatype;
}

const SerdNode*
serd_node_language(const SerdNode* const node)
{
  if (!node || !(node->flags & SERD_HAS_LANGUAGE)) {
    return NULL;
  }

  const SerdNode* const lang = serd_node_meta_node(node);
  assert(lang->type == SERD_LITERAL);
  return lang;
}

SerdNodeFlags
serd_node_flags(const SerdNode* const node)
{
  return node->flags;
}

void
serd_node_free(SerdNode* const node)
{
  serd_free_aligned(node);
}