/**
 * @file di/encoding/me.h
 * Generic matching engine
 */
#ifndef DI_ENCODING_ME_H__
#define DI_ENCODING_ME_H__

#ifdef __cplusplus
extern "C" {
#endif

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

#include <di/buffer.h>

#ifdef __cplusplus
#define DI_ME_ITEM_STR(_s) reinterpret_cast < const uint8_t * > (_s), sizeof(_s) - 1
#else
#define DI_ME_ITEM_STR(_s) .s = (const uint8_t *)_s, .size = sizeof(_s) - 1
#endif

/**
 * Matching engine item state
 */
enum di_me_item_states {
	DI_ME_STATE_NO_MATCH    = 0, /**< Item not matched */
	DI_ME_STATE_UNMATCHABLE = 1, /**< Item is unmatchable */
	DI_ME_STATE_CAN_MATCH   = 2, /**< Item can match */
	DI_ME_STATE_MATCHED     = 3  /**< Item is matched */
};

/**
 * Matching engine item flags
 */
enum di_me_item_flags {
	DI_ME_ITEM_FLAGS_DEFAULTS   = 0,        /**< Default flags are used from di_me_ctx.cfg.flags */
	DI_ME_ITEM_FLAG_CB_ON_MATCH = (1 << 0), /**< Execute callback on match */
	DI_ME_ITEM_FLAG_CB_ON_RESET = (1 << 1)  /**< Execute callback on reset */
};

/**
 * Matching engine context
 */
struct di_me_ctx {
	struct di_buffer reader;
	struct di_buffer linebuffer;
	struct di_buffer cc; /** Carbon copy buffer */

	/** Configuration */
	struct cfg {
		uint8_t flags;              /**< Default item flags */
		uint8_t reset_char;         /**< Statemachine reset character */
		void *private_data;         /**< Private data field for callback context */
	} cfg;

	struct match {
		const struct di_me_item *item; /**< Current matched item */
		size_t pos;                    /**< Current position of match */
		char *str;                     /**< Matched item string in linbuffer */
	} match;

	struct items {
		const struct di_me_item *list; /**< Items to match */
		enum di_me_item_states *state; /**< Items state */
		size_t n;                      /**< Items count */
	} items;
};

/**
 * Matching item
 */
struct di_me_item {
	const uint8_t *s;                  /**< Item string */
	const size_t size;                 /**< String size */
	uint8_t flags;                     /**< Item flags, when set to DI_ME_ITEM_FLAGS_DEFAULTS.
										* di_me_ctx.cfg.flags is used
										*/
	void (*cb)(struct di_me_ctx *ctx); /**< Item match callback */
};

/**
 * Reset matching engine
 * - Clear ctx->cfg.linebuffer.data
 * - Set all ctx->item->flags to default when set to DI_ME_ITEM_FLAGS_DEFAULTS
 * - Set all ctx->items state to NOMATCH
 * - Set ctx->pos = 0
 * - Set ctx->match_prev
 * - Set ctx->match = NULL
 */
void di_me_reset(struct di_me_ctx *ctx);

/**
 * Feed the matching engine data with size
 */
void di_me_feed(struct di_me_ctx *ctx, void *data, size_t n);

/** Count amount of ocurrences of character in string */
size_t di_me_char_count(const char *str, char c);

/** Replace first ocurrence of s in string
 * @param str String (null terminated)
 * @param s   List of characters to search for (null terminated)
 * @param c   Character of replacement
 */
void di_me_chrrep(char *str, const char *s, char c);

#ifdef __cplusplus
}
#endif

#endif /* DI_ENCODING_ME_H__ */