#include <stdlib.h>	/* we need size_t */
#include <json.h>
#include <libestr.h>

/* error codes */
#define LN_NOMEM -1
#define LN_INVLDFDESCR -1
#define LN_WRONGPARSER -1000

/**
 * The library context descriptor.
 * This is used to permit multiple independent instances of the
 * library to be called within a single program. This is most
 * useful for plugin-based architectures.
 */
typedef struct ln_ctx_s* ln_ctx;

/* API */
/**
 * Return library version string.
 *
 * Returns the version of the currently used library.
 *
 * @return Zero-Terminated library version string.
 */
/* Note: this MUST NOT be inline to make sure the actual library
 * has the right version, not just what was used to compile!
 */
char *ln_version(void);

/**
 * Initialize a library context.
 *
 * To prevent memory leaks, ln_exitCtx() must be called on a library
 * context that is no longer needed.
 *
 * @return new library context or NULL if an error occured
 */
ln_ctx ln_initCtx(void);

/**
 * Discard a library context.
 *
 * Free's the ressources associated with the given library context. It
 * MUST NOT be accessed after calling this function.
 *
 * @param ctx The context to be discarded.
 *
 * @return Returns zero on success, something else otherwise.
 */
int ln_exitCtx(ln_ctx ctx);


/**
 * Set a debug message handler (callback).
 *
 * Liblognorm can provide helpful information for debugging
 * - it's internal processing
 * - the way a log message is being normalized
 *
 * It does so by emiting "interesting" information about its processing
 * at various stages. A caller can obtain this information by registering
 * an entry point. When done so, liblognorm will call the entry point
 * whenever it has something to emit. Note that debugging can be rather
 * verbose.
 *
 * The callback will be called with the following three parameters in that order:
 * - the caller-provided cookie
 * - a zero-terminated string buffer
 * - the length of the string buffer, without the trailing NUL byte
 *
 * @note
 * The provided callback function <b>must not</b> call any liblognorm
 * APIs except when specifically flagged as safe for calling by a debug
 * callback handler.
 *
 * @param[in] ctx The library context to apply callback to.
 * @param[in] cb The function to be called for debugging
 * @param[in] cookie Opaque cookie to be passed down to debug handler. Can be
 *                   used for some state tracking by the caller. This is defined as
 *                   void* to support pointers. To play it safe, a pointer should be
 *                   passed (but advantorous folks may also use an unsigned).
 *
 * @return Returns zero on success, something else otherwise.
 */
int ln_setDebugCB(ln_ctx ctx, void (*cb)(void*, const char*, size_t), void *cookie);


/**
 * enable or disable debug mode.
 *
 * @param[in] ctx context
 * @param[in] b boolean 0 - disable debug mode, 1 - enable debug mode
 */
void ln_enableDebug(ln_ctx ctx, int i);

/**
 * Reads a sample stored in buffer buf and creates a new ln_samp object
 * out of it.
 *
 * @note
 * It is the caller's responsibility to delete the newly
 * created ln_samp object if it is no longer needed.
 *
 * @param[ctx] ctx current library context
 * @param[buf] NULL terminated cstr containing the contents of the sample
 * @return Returns zero on success, something else otherwise.
 */
int
ln_loadSample(ln_ctx ctx, const char *buf);

/**
 * Load a (log) sample file.
 *
 * The file must contain log samples in syntactically correct format. Samples are added
 * to set already loaded in the current context. If there is a sample with duplicate
 * semantics, this sample will be ignored. Most importantly, this can \b not be used
 * to change tag assignments for a given sample.
 *
 * @param[in] ctx The library context to apply callback to.
 * @param[in] file Name of file to be loaded.
 *
 * @return Returns zero on success, something else otherwise.
 */
int ln_loadSamples(ln_ctx ctx, const char *file);

/**
 * Normalize a message.
 *
 * This is the main library entry point. It is called with a message
 * to normalize and will return a normalized in-memory representation
 * of it.
 *
 * If an error occurs, the function returns -1. In that case, an
 * in-memory event representation has been generated if event is
 * non-NULL. In that case, the event contains further error details in
 * normalized form.
 *
 * @note
 * This function works on byte-counted strings and as such is able to
 * process NUL bytes if they occur inside the message. On the other hand,
 * this means the the correct messages size, \b excluding the NUL byte,
 * must be provided.
 *
 * @param[in] ctx The library context to use.
 * @param[in] str The message string (see note above).
 * @param[in] strLen The length of the message in bytes.
 * @param[out] json_p A new event record or NULL if an error occured. <b>Must be
 *                   destructed if no longer needed.</b>
 *
 * @return Returns zero on success, something else otherwise.
 */
int ln_normalize(ln_ctx ctx, const char *str, size_t strLen, struct json_object **json_p);