#pragma once

#ifndef _CWALK_H_
#define _CWALK_H_

#include <stdbool.h>
#include <stddef.h>

/**
 * A segment represents a single component of a path. For instance, on linux a
 * path might look like this "/var/log/", which consists of two segments "var"
 * and "log".
 */
struct cwk_segment {
	const char *path;
	const char *segments;
	const char *begin;
	const char *end;
	size_t size;
};

/**
 * The segment type can be used to identify whether a segment is a special
 * segment or not.
 *
 * CWK_NORMAL - normal folder or file segment
 * CWK_CURRENT - "./" current folder segment
 * CWK_BACK - "../" relative back navigation segment
 */
enum cwk_segment_type {
	CWK_NORMAL,
	CWK_CURRENT,
	CWK_BACK
};

/**
 * @brief Determines the style which is used for the path parsing and
 * generation.
 */
enum cwk_path_style {
	CWK_STYLE_WINDOWS,
	CWK_STYLE_UNIX
};

/**
 * @brief Generates an absolute path based on a base.
 *
 * This function generates an absolute path based on a base path and another
 * path. It is guaranteed to return an absolute path. If the second submitted
 * path is absolute, it will override the base path. The result will be written
 * to a buffer, which might be truncated if the buffer is not large enough to
 * hold the full path. However, the truncated result will always be
 * null-terminated. The returned value is the amount of characters which the
 * resulting path would take if it was not truncated (excluding the
 * null-terminating character).
 *
 * @param base The base path on which the relative path will be applied.
 * @param path The relative path which will be applied on the base path.
 * @param buffer The buffer where the result will be written to.
 * @param buffer_size The size of the result buffer.
 * @return Returns the total amount of characters of the new absolute path.
 */
size_t cwk_path_get_absolute(const char *base, const char *path, char *buffer,
			     size_t buffer_size);

/**
 * @brief Generates a relative path based on a base.
 *
 * This function generates a relative path based on a base path and another
 * path. It determines how to get to the submitted path, starting from the base
 * directory. The result will be written to a buffer, which might be truncated
 * if the buffer is not large enough to hold the full path. However, the
 * truncated result will always be null-terminated. The returned value is the
 * amount of characters which the resulting path would take if it was not
 * truncated (excluding the null-terminating character).
 *
 * @param base_directory The base path from which the relative path will start.
 * @param path The target path where the relative path will point to.
 * @param buffer The buffer where the result will be written to.
 * @param buffer_size The size of the result buffer.
 * @return Returns the total amount of characters of the full path.
 */
size_t cwk_path_get_relative(const char *base_directory, const char *path,
			     char *buffer, size_t buffer_size);

/**
 * @brief Joins two paths together.
 *
 * This function generates a new path by combining the two submitted paths. It
 * will remove double separators, and unlike cwk_path_get_absolute it permits
 * the use of two relative paths to combine. The result will be written to a
 * buffer, which might be truncated if the buffer is not large enough to hold
 * the full path. However, the truncated result will always be null-terminated.
 * The returned value is the amount of characters which the resulting path would
 * take if it was not truncated (excluding the null-terminating character).
 *
 * @param path_a The first path which comes first.
 * @param path_b The second path which comes after the first.
 * @param buffer The buffer where the result will be written to.
 * @param buffer_size The size of the result buffer.
 * @return Returns the total amount of characters of the full, combined path.
 */
size_t cwk_path_join(const char *path_a, const char *path_b, char *buffer,
		     size_t buffer_size);

/**
 * @brief Joins multiple paths together.
 *
 * This function generates a new path by joining multiple paths together. It
 * will remove double separators, and unlike cwk_path_get_absolute it permits
 * the use of multiple relative paths to combine. The last path of the submitted
 * string array must be set to NULL. The result will be written to a buffer,
 * which might be truncated if the buffer is not large enough to hold the full
 * path. However, the truncated result will always be null-terminated. The
 * returned value is the amount of characters which the resulting path would
 * take if it was not truncated (excluding the null-terminating character).
 *
 * @param paths An array of paths which will be joined.
 * @param buffer The buffer where the result will be written to.
 * @param buffer_size The size of the result buffer.
 * @return Returns the total amount of characters of the full, combined path.
 */
size_t cwk_path_join_multiple(const char **paths, char *buffer,
			      size_t buffer_size);

/**
 * @brief Determines the root of a path.
 *
 * This function determines the root of a path by finding it's length. The root
 * always starts at the submitted path. If the path has no root, the length will
 * be set to zero.
 *
 * @param path The path which will be inspected.
 * @param length The output of the root length.
 */
void cwk_path_get_root(const char *path, size_t *length);

/**
 * @brief Changes the root of a path.
 *
 * This function changes the root of a path. It does not normalize the result.
 * The result will be written to a buffer, which might be truncated if the
 * buffer is not large enough to hold the full path. However, the truncated
 * result will always be null-terminated. The returned value is the amount of
 * characters which the resulting path would take if it was not truncated
 * (excluding the null-terminating character).
 *
 * @param path The original path which will get a new root.
 * @param new_root The new root which will be placed in the path.
 * @param buffer The output buffer where the result is written to.
 * @param buffer_size The size of the output buffer where the result is written
 * to.
 * @return Returns the total amount of characters of the new path.
 */
size_t cwk_path_change_root(const char *path, const char *new_root,
			    char *buffer, size_t buffer_size);

/**
 * @brief Determine whether the path is absolute or not.
 *
 * This function checks whether the path is an absolute path or not. A path is
 * considered to be absolute if the root ends with a separator.
 *
 * @param path The path which will be checked.
 * @return Returns true if the path is absolute or false otherwise.
 */
bool cwk_path_is_absolute(const char *path);

/**
 * @brief Determine whether the path is relative or not.
 *
 * This function checks whether the path is a relative path or not. A path is
 * considered to be relative if the root does not end with a separator.
 *
 * @param path The path which will be checked.
 * @return Returns true if the path is relative or false otherwise.
 */
bool cwk_path_is_relative(const char *path);

/**
 * @brief Gets the basename of a file path.
 *
 * This function gets the basename of a file path. A pointer to the beginning of
 * the basename will be returned through the basename parameter. This pointer
 * will be positioned on the first letter after the separator. The length of the
 * file path will be returned through the length parameter. The length will be
 * set to zero and the basename to NULL if there is no basename available.
 *
 * @param path The path which will be inspected.
 * @param basename The output of the basename pointer.
 * @param length The output of the length of the basename.
 */
void cwk_path_get_basename(const char *path, const char **basename,
			   size_t *length);

/**
 * @brief Changes the basename of a file path.
 *
 * This function changes the basename of a file path. This function will not
 * write out more than the specified buffer can contain. However, the generated
 * string is always null-terminated - even if not the whole path is written out.
 * The function returns the total number of characters the complete buffer would
 * have, even if it was not written out completely. The path may be the same
 * memory address as the buffer.
 *
 * @param path The original path which will be used for the modified path.
 * @param new_basename The new basename which will replace the old one.
 * @param buffer The buffer where the changed path will be written to.
 * @param buffer_size The size of the result buffer where the changed path is
 * written to.
 * @return Returns the size which the complete new path would have if it was not
 * truncated.
 */
size_t cwk_path_change_basename(const char *path, const char *new_basename,
				char *buffer, size_t buffer_size);

/**
 * @brief Gets the dirname of a file path.
 *
 * This function determines the dirname of a file path and returns the length up
 * to which character is considered to be part of it. If no dirname is found,
 * the length will be set to zero. The beginning of the dirname is always equal
 * to the submitted path pointer.
 *
 * @param path The path which will be inspected.
 * @param length The length of the dirname.
 */
void cwk_path_get_dirname(const char *path, size_t *length);

/**
 * @brief Gets the extension of a file path.
 *
 * This function extracts the extension portion of a file path. A pointer to
 * the beginning of the extension will be returned through the extension
 * parameter if an extension is found and true is returned. This pointer will be
 * positioned on the dot. The length of the extension name will be returned
 * through the length parameter. If no extension is found both parameters won't
 * be touched and false will be returned.
 *
 * @param path The path which will be inspected.
 * @param extension The output of the extension pointer.
 * @param length The output of the length of the extension.
 * @return Returns true if an extension is found or false otherwise.
 */
bool cwk_path_get_extension(const char *path, const char **extension,
			    size_t *length);

/**
 * @brief Determines whether the file path has an extension.
 *
 * This function determines whether the submitted file path has an extension.
 * This will evaluate to true if the last segment of the path contains a dot.
 *
 * @param path The path which will be inspected.
 * @return Returns true if the path has an extension or false otherwise.
 */
bool cwk_path_has_extension(const char *path);

/**
 * @brief Changes the extension of a file path.
 *
 * This function changes the extension of a file name. The function will append
 * an extension if the basename does not have an extension, or use the extension
 * as a basename if the path does not have a basename. This function will not
 * write out more than the specified buffer can contain. However, the generated
 * string is always null-terminated - even if not the whole path is written out.
 * The function returns the total number of characters the complete buffer would
 * have, even if it was not written out completely. The path may be the same
 * memory address as the buffer.
 *
 * @param path The path which will be used to make the change.
 * @param new_extension The extension which will be placed within the new path.
 * @param buffer The output buffer where the result will be written to.
 * @param buffer_size The size of the output buffer where the result will be
 * written to.
 * @return Returns the total size which the output would have if it was not
 * truncated.
 */
size_t cwk_path_change_extension(const char *path, const char *new_extension,
				 char *buffer, size_t buffer_size);

/**
 * @brief Creates a normalized version of the path.
 *
 * This function creates a normalized version of the path within the specified
 * buffer. This function will not write out more than the specified buffer can
 * contain. However, the generated string is always null-terminated - even if
 * not the whole path is written out. The function returns the total number of
 * characters the complete buffer would have, even if it was not written out
 * completely. The path may be the same memory address as the buffer.
 *
 * The following will be true for the normalized path:
 * 1) "../" will be resolved.
 * 2) "./" will be removed.
 * 3) double separators will be fixed with a single separator.
 * 4) separator suffixes will be removed.
 *
 * @param path The path which will be normalized.
 * @param buffer The buffer where the new path is written to.
 * @param buffer_size The size of the buffer.
 * @return The size which the complete normalized path has if it was not
 * truncated.
 */
size_t cwk_path_normalize(const char *path, char *buffer, size_t buffer_size);

/**
 * @brief Finds common portions in two paths.
 *
 * This function finds common portions in two paths and returns the number
 * characters from the beginning of the base path which are equal to the other
 * path.
 *
 * @param path_base The base path which will be compared with the other path.
 * @param path_other The other path which will compared with the base path.
 * @return Returns the number of characters which are common in the base path.
 */
size_t cwk_path_get_intersection(const char *path_base, const char *path_other);

/**
 * @brief Gets the first segment of a path.
 *
 * This function finds the first segment of a path. The position of the segment
 * is set to the first character after the separator, and the length counts all
 * characters until the next separator (excluding the separator).
 *
 * @param path The path which will be inspected.
 * @param segment The segment which will be extracted.
 * @return Returns true if there is a segment or false if there is none.
 */
bool cwk_path_get_first_segment(const char *path, struct cwk_segment *segment);

/**
 * @brief Gets the last segment of the path.
 *
 * This function gets the last segment of a path. This function may return false
 * if the path doesn't contain any segments, in which case the submitted segment
 * parameter is not modified. The position of the segment is set to the first
 * character after the separator, and the length counts all characters until the
 * end of the path (excluding the separator).
 *
 * @param path The path which will be inspected.
 * @param segment The segment which will be extracted.
 * @return Returns true if there is a segment or false if there is none.
 */
bool cwk_path_get_last_segment(const char *path, struct cwk_segment *segment);

/**
 * @brief Advances to the next segment.
 *
 * This function advances the current segment to the next segment. If there are
 * no more segments left, the submitted segment structure will stay unchanged
 * and false is returned.
 *
 * @param segment The current segment which will be advanced to the next one.
 * @return Returns true if another segment was found or false otherwise.
 */
bool cwk_path_get_next_segment(struct cwk_segment *segment);

/**
 * @brief Moves to the previous segment.
 *
 * This function moves the current segment to the previous segment. If the
 * current segment is the first one, the submitted segment structure will stay
 * unchanged and false is returned.
 *
 * @param segment The current segment which will be moved to the previous one.
 * @return Returns true if there is a segment before this one or false
 * otherwise.
 */
bool cwk_path_get_previous_segment(struct cwk_segment *segment);

/**
 * @brief Gets the type of the submitted path segment.
 *
 * This function inspects the contents of the segment and determines the type of
 * it. Currently, there are three types CWK_NORMAL, CWK_CURRENT and CWK_BACK. A
 * CWK_NORMAL segment is a normal folder or file entry. A CWK_CURRENT is a "./"
 * and a CWK_BACK a "../" segment.
 *
 * @param segment The segment which will be inspected.
 * @return Returns the type of the segment.
 */
enum cwk_segment_type cwk_path_get_segment_type(
	const struct cwk_segment *segment);

/**
 * @brief Changes the content of a segment.
 *
 * This function overrides the content of a segment to the submitted value and
 * outputs the whole new path to the submitted buffer. The result might require
 * less or more space than before if the new value length differs from the
 * original length. The output is truncated if the new path is larger than the
 * submitted buffer size, but it is always null-terminated. The source of the
 * segment and the submitted buffer may be the same.
 *
 * @param segment The segment which will be modifier.
 * @param value The new content of the segment.
 * @param buffer The buffer where the modified path will be written to.
 * @param buffer_size The size of the output buffer.
 * @return Returns the total size which would have been written if the output
 * was not truncated.
 */
size_t cwk_path_change_segment(struct cwk_segment *segment, const char *value,
			       char *buffer, size_t buffer_size);

/**
 * @brief Checks whether the submitted pointer points to a separator.
 *
 * This function simply checks whether the submitted pointer points to a
 * separator, which has to be null-terminated (but not necessarily after the
 * separator). The function will return true if it is a separator, or false
 * otherwise.
 *
 * @param symbol A pointer to a string.
 * @return Returns true if it is a separator, or false otherwise.
 */
bool cwk_path_is_separator(const char *str);

/**
 * @brief Guesses the path style.
 *
 * This function guesses the path style based on a submitted path-string. The
 * guessing will look at the root and the type of slashes contained in the path
 * and return the style which is more likely used in the path.
 *
 * @param path The path which will be inspected.
 * @return Returns the style which is most likely used for the path.
 */
enum cwk_path_style cwk_path_guess_style(const char *path);

/**
 * @brief Configures which path style is used.
 *
 * This function configures which path style is used. The following styles are
 * currently supported.
 *
 * CWK_STYLE_WINDOWS: Use backslashes as a separator and volume for the root.
 * CWK_STYLE_UNIX: Use slashes as a separator and a slash for the root.
 *
 * @param style The style which will be used from now on.
 */
void cwk_path_set_style(enum cwk_path_style style);

/**
 * @brief Gets the path style configuration.
 *
 * This function gets the style configuration which is currently used for the
 * paths. This configuration determines how paths are parsed and generated.
 *
 * @return Returns the current path style configuration.
 */
enum cwk_path_style cwk_path_get_style(void);

#endif /* _CWALK_H_ */
