/*
  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 "serd/serd.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

SerdNode
serd_node_from_string(SerdType type, const char* str)
{
  if (!str) {
    return SERD_NODE_NULL;
  }

  SerdNodeFlags  flags   = 0;
  const size_t   n_bytes = serd_strlen(str, &flags);
  const SerdNode ret     = {str, n_bytes, flags, type};
  return ret;
}

SerdNode
serd_node_from_substring(SerdType type, const char* str, const size_t len)
{
  if (!str) {
    return SERD_NODE_NULL;
  }

  SerdNodeFlags  flags   = 0;
  const size_t   n_bytes = serd_substrlen(str, len, &flags);
  const SerdNode ret     = {str, n_bytes, flags, type};
  return ret;
}

SerdNode
serd_node_copy(const SerdNode* node)
{
  if (!node || !node->buf) {
    return SERD_NODE_NULL;
  }

  SerdNode copy = *node;
  char*    buf  = (char*)malloc(copy.n_bytes + 1);
  memcpy(buf, node->buf, copy.n_bytes + 1);
  copy.buf = buf;
  return copy;
}

bool
serd_node_equals(const SerdNode* a, const SerdNode* b)
{
  return (a == b) ||
         (a->type == b->type && a->n_bytes == b->n_bytes &&
          ((a->buf == b->buf) || !memcmp(a->buf, b->buf, a->n_bytes + 1)));
}

static size_t
serd_uri_string_length(const SerdURIView* uri)
{
  size_t len = uri->path_base.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* buf, size_t len, void* stream)
{
  char** ptr = (char**)stream;
  memcpy(*ptr, buf, len);
  *ptr += len;
  return len;
}

SerdNode
serd_node_new_uri_from_node(const SerdNode*    uri_node,
                            const SerdURIView* base,
                            SerdURIView*       out)
{
  return (uri_node->type == SERD_URI && uri_node->buf)
           ? serd_node_new_uri_from_string(uri_node->buf, base, out)
           : SERD_NODE_NULL;
}

SerdNode
serd_node_new_uri_from_string(const char*        str,
                              const SerdURIView* base,
                              SerdURIView*       out)
{
  if (!str || str[0] == '\0') {
    // Empty URI => Base URI, or nothing if no base is given
    return base ? serd_node_new_uri(base, NULL, out) : SERD_NODE_NULL;
  }

  SerdURIView uri;
  serd_uri_parse(str, &uri);
  return serd_node_new_uri(&uri, base, out); // Resolve/Serialise
}

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

  switch (c) {
  // unreserved:
  case '-':
  case '.':
  case '_':
  case '~':
  // pchar:
  case ':':
  case '@':
  // separator:
  case '/':
  // sub-delimeters:
  case '!':
  case '$':
  case '&':
  case '\'':
  case '(':
  case ')':
  case '*':
  case '+':
  case ',':
  case ';':
  case '=':
    return true;
  default:
    return false;
  }
}

SerdNode
serd_node_new_file_uri(const char* path, const char* hostname, SerdURIView* out)
{
  const size_t path_len     = strlen(path);
  const size_t hostname_len = hostname ? strlen(hostname) : 0;
  const bool   is_windows   = is_windows_path(path);
  size_t       uri_len      = 0;
  char*        uri          = NULL;

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

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

    if (hostname) {
      memcpy(uri + 7, hostname, 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[i] == '\\') {
      serd_buffer_sink("/", 1, &buffer);
    } else if (path[i] == '%') {
      serd_buffer_sink("%%", 2, &buffer);
    } else if (is_uri_path_char(path[i])) {
      serd_buffer_sink(path + 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[i]);
      serd_buffer_sink(escape_str, 3, &buffer);
    }
  }
  serd_buffer_sink_finish(&buffer);

  if (out) {
    serd_uri_parse((const char*)buffer.buf, out);
  }

  return serd_node_from_substring(
    SERD_URI, (const char*)buffer.buf, buffer.len);
}

SerdNode
serd_node_new_uri(const SerdURIView* uri,
                  const SerdURIView* base,
                  SerdURIView*       out)
{
  SerdURIView abs_uri = *uri;
  if (base) {
    serd_uri_resolve(uri, base, &abs_uri);
  }

  const size_t len        = serd_uri_string_length(&abs_uri);
  char*        buf        = (char*)malloc(len + 1);
  SerdNode     node       = {buf, len, 0, SERD_URI};
  char*        ptr        = buf;
  const size_t actual_len = serd_uri_serialise(&abs_uri, string_sink, &ptr);

  buf[actual_len] = '\0';
  node.n_bytes    = actual_len;

  if (out) {
    serd_uri_parse(buf, out); // TODO: cleverly avoid double parse
  }

  return node;
}

SerdNode
serd_node_new_relative_uri(const SerdURIView* uri,
                           const SerdURIView* base,
                           const SerdURIView* root,
                           SerdURIView*       out)
{
  const size_t uri_len  = serd_uri_string_length(uri);
  const size_t base_len = serd_uri_string_length(base);
  char*        buf      = (char*)malloc(uri_len + base_len + 1);
  SerdNode     node     = {buf, 0, 0, SERD_URI};
  char*        ptr      = buf;
  const size_t actual_len =
    serd_uri_serialise_relative(uri, base, root, string_sink, &ptr);

  buf[actual_len] = '\0';
  node.n_bytes    = actual_len;

  if (out) {
    serd_uri_parse(buf, out); // TODO: cleverly avoid double parse
  }

  return node;
}

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

SerdNode
serd_node_new_decimal(double d, unsigned frac_digits)
{
  if (isnan(d) || isinf(d)) {
    return SERD_NODE_NULL;
  }

  const double   abs_d      = fabs(d);
  const unsigned int_digits = serd_digits(abs_d);
  char*          buf        = (char*)calloc(int_digits + frac_digits + 3, 1);
  SerdNode       node       = {buf, 0, 0, SERD_LITERAL};
  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.n_bytes = (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.n_bytes = (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_node_new_integer(int64_t i)
{
  uint64_t       abs_i  = (i < 0) ? -i : i;
  const unsigned digits = serd_digits((double)abs_i);
  char*          buf    = (char*)calloc(digits + 2, 1);
  SerdNode       node   = {(const char*)buf, 0, 0, SERD_LITERAL};

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

  node.n_bytes = (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_node_new_blob(const void* buf, size_t size, bool wrap_lines)
{
  const size_t len  = serd_base64_get_length(size, wrap_lines);
  uint8_t*     str  = (uint8_t*)calloc(len + 2, 1);
  SerdNode     node = {(const char*)str, len, 0, SERD_LITERAL};

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

void
serd_node_free(SerdNode* node)
{
  if (node && node->buf) {
    free((char*)node->buf);
    node->buf = NULL;
  }
}