#ifndef MYCLIB_STRING_H
#define MYCLIB_STRING_H

#include <stddef.h>
#include <threads.h>

/**
 * @brief Thread-safe dynamic string structure.
 */
typedef struct string {
	char *data;		 /**< Pointer to null-terminated string data */
	size_t size;	 /**< Current length (excluding null terminator) */
	size_t capacity; /**< Allocated capacity including null terminator */
	mtx_t lock;		 /**< Mutex for thread safety */
} string_s;

/**
 * @brief Create a new string initialized with the given text.
 *
 * @param text Initial text.
 * @param initial_capacity Initial buffer capacity (including null terminator). Pass 0 to
 * auto-calculate.
 * @return Pointer to the new string, or NULL on failure.
 */
string_s *string_new(const char *text, size_t initial_capacity);

/**
 * @brief Free the string and its resources.
 *
 * @param string String to free (safe to call with NULL).
 */
void string_free(string_s *string);

/**
 * @brief Append text to the string.
 *
 * @param string String to modify.
 * @param text Text to append.
 * @return 0 on success, -1 on failure.
 */
int string_append(string_s *string, const char *text);

/**
 * @brief Extend by adding another string.
 *
 * @param destination Destination string.
 * @param source Source string.
 * @return 0 on success, -1 on failure.
 */
int string_extend(string_s *destination, string_s *source);

/**
 * @brief Clear the string content without freeing the memory.
 *
 * @param string String to clear.
 * @return 0 on success, -1 on failure.
 */
int string_clear(string_s *string);

/**
 * @brief Get the current length of the string.
 *
 * @param string String to query.
 * @return Length excluding null terminator, or 0 if NULL.
 */
size_t string_len(string_s *string);

/**
 * @brief Get the total allocated capacity of the string buffer.
 *
 * @param string String to query.
 * @return Capacity in bytes (including null terminator), or 0 if NULL.
 */
size_t string_cap(string_s *string);

/**
 * @brief Get a pointer to a null-terminated C-string.
 *
 * @param string String to read.
 * @return Pointer to string->data.
 *
 * @note See string_lock().
 */
char *string_cstr(string_s *string);

/**
 * @brief Create a heap-allocated copy of the string content.
 *
 * @param string String to copy.
 * @return Newly allocated null-terminated buffer, or NULL on failure.
 *
 * @note The caller is responsible for freeing the returned buffer with free().
 * See string_lock().
 */
char *string_copy(string_s *string);

/**
 * @brief Lock the string for safe reading or writing.
 *
 * @param string String to lock.
 * @return 0 on success, -1 on failure.
 *
 * @note Use this before calling string_cstr() if you want a stable pointer.
 */
int string_lock(string_s *string);

/**
 * @brief Unlock a previously locked string.
 *
 * @param string String to unlock.
 * @return 0 on success, -1 on failure.
 */
int string_unlock(string_s *string);

/**
 * @brief Compare two strings.
 *
 * @param s1 First string.
 * @param s2 Second string.
 * @return -123 on failure or same as strcmp().
 */
int string_compare(string_s *s1, string_s *s2);

/**
 * @brief Convert the string to uppercase.
 *
 * @param string String to modify.
 * @return 0 on success, -1 on failure.
 */
int string_toupper(string_s *string);

/**
 * @brief Convert the string to lowercase.
 *
 * @param string String to modify.
 * @return 0 on success, -1 on failure.
 */
int string_tolower(string_s *string);

/**
 * @brief Find a substring inside a string.
 *
 * @param string String where to search.
 * @param substring Substring to search.
 * @return Index of the first occurrence, -1 on failure.
 */
int string_find(string_s *string, const char *substring);

/**
 * @brief Create a formatted string (like printf).
 *
 * @param fmt Format string.
 * @param ... Arguments for format.
 * @return New string, or NULL on failure.
 */
string_s *string_format(const char *fmt, ...);

/**
 * @brief Insert text at a specific position.
 *
 * @param string String to modify.
 * @param index Position where to insert.
 * @param text Text to insert.
 * @return 0 on success, -1 on failure.
 */
int string_insert(string_s *string, size_t index, const char *text);

/**
 * @brief Replace all occurrences of a substring with another.
 *
 * @param string String to modify.
 * @param old_text Substring to replace.
 * @param new_text Replacement text.
 * @return 0 on success, -1 on failure.
 */
int string_replace(string_s *string, const char *old_text, const char *new_text);

/**
 * @brief Remove part of the string.
 *
 * @param string String to modify.
 * @param index Starting position.
 * @param length Number of characters to remove.
 * @return 0 on success, -1 on failure.
 */
int string_remove(string_s *string, size_t index, size_t length);

#endif /* MYCLIB_STRING_H */