// Copyright 2011-2020 David Robillard <d@drobilla.net>
// SPDX-License-Identifier: ISC

#ifndef SERD_URI_UTILS_H
#define SERD_URI_UTILS_H

#include "serd/serd.h"

#include "string_utils.h"

#include <stdbool.h>
#include <stdint.h>
#include <string.h>

static inline bool
chunk_equals(const SerdChunk* a, const SerdChunk* b)
{
  return a->len == b->len &&
         !strncmp((const char*)a->buf, (const char*)b->buf, a->len);
}

static inline size_t
uri_path_len(const SerdURI* uri)
{
  return uri->path_base.len + uri->path.len;
}

static inline uint8_t
uri_path_at(const SerdURI* uri, size_t i)
{
  return (i < uri->path_base.len) ? uri->path_base.buf[i]
                                  : uri->path.buf[i - uri->path_base.len];
}

/**
   Return the index of the first differing character after the last root slash,
   or zero if `uri` is not under `root`.
*/
static inline SERD_PURE_FUNC size_t
uri_rooted_index(const SerdURI* uri, const SerdURI* root)
{
  if (!root || !root->scheme.len ||
      !chunk_equals(&root->scheme, &uri->scheme) ||
      !chunk_equals(&root->authority, &uri->authority)) {
    return 0;
  }

  bool         differ          = false;
  const size_t path_len        = uri_path_len(uri);
  const size_t root_len        = uri_path_len(root);
  size_t       last_root_slash = 0;
  for (size_t i = 0; i < path_len && i < root_len; ++i) {
    const uint8_t u = uri_path_at(uri, i);
    const uint8_t r = uri_path_at(root, i);

    differ = differ || u != r;
    if (r == '/') {
      last_root_slash = i;
      if (differ) {
        return 0;
      }
    }
  }

  return last_root_slash + 1;
}

/** Return true iff `uri` shares path components with `root` */
static inline SERD_PURE_FUNC bool
uri_is_related(const SerdURI* uri, const SerdURI* root)
{
  return uri_rooted_index(uri, root) > 0;
}

/** Return true iff `uri` is within the base of `root` */
static inline SERD_PURE_FUNC bool
uri_is_under(const SerdURI* uri, const SerdURI* root)
{
  const size_t index = uri_rooted_index(uri, root);
  return index > 0 && uri->path.len > index;
}

static inline bool
is_uri_scheme_char(const int c)
{
  switch (c) {
  case ':':
  case '+':
  case '-':
  case '.':
    return true;
  default:
    return is_alpha(c) || is_digit(c);
  }
}

#endif // SERD_URI_UTILS_H