#ifndef SLC_H
#define SLC_H

/** A word starts right after this - a word is usually after this memory area */
struct wordstart {
	/* : */
	char colon;
	/* whitespace after ':', usually used to store the flags */
	uint8_t flags;
	/* char name[]; // The name of the word being defined. */
	/* char vars[]; // The local variables of the word. */
	/* char data[]; // The "body" of the word - either text source or after processing the threaded code of it (see flags) */
};

enum SLC_SYM_OP { SLC_SYM_SET, SLC_SYM_GET, SLC_SYM_ERASE };
enum SLC_STACK_OP { SLC_STACK_PUSH, SLC_STACK_POP, SLC_STACK_AT, SLC_STACK_COUNT, SLC_STACK_ERASE };
enum SLC_SESSION_OP { SLC_SESSION_ALLOC, SLC_SESSION_ERASE, SLC_SESSION_GET };
enum SLC_IO_OP {
	SLC_IO_OPEN,
	SLC_IO_OPEN_TMP,
	SLC_IO_REMOVE_TMPS,
	SLC_IO_CLOSE,
	SLC_IO_READ,
	SLC_IO_WRITE,
	SLC_IO_LOCK,
	SLC_IO_UNLOCK,
	SLC_IO_CMD,
};

/**
 * Function-abstraction for a "symbol-table".
 *
 * Operations:
 *
 * 		SLC_SYM_SET Saves a mapping from key->word in symbol table. word==NULL removes mapping. Returns ptr back or NULL on errors.
 * 		SLC_SYM_GET Gets the symbol at key (the word parameter is unused). Returns NULL if there is no word for the key.
 * 		SLC_SYM_ERASE Erases the symbol table so it becomes empty again. Can never fail, returns NULL.
 *
 * @param op Defines which operation the caller wants.
 * @param key The key (both for SET and GET)
 * @param word When adding a found word to the symbol table, the key will point to this word
 * @returns The word definition stored for the key, or NULL when it is not stored yet or op is SET and there was an error.
 */
typedef wordstart* (*sym)(SLC_SYM_OP op, char *key, wordstart *word);

/**
 * Function-abstraction for an integer "stack".
 *
 * Operations:
 * 
 * 		SLC_STACK_PUSH pushes the "elem" to the stack. Returns 1 if succeeded, otherwise 0.
 * 		SLC_STACK_POP pops the stack - does not return meaningful value, beware of underflowing!
 * 		SLC_STACK_AT returns the "param"th element down from the top of the stack
 * 		SLC_STACK_COUNT returns the number of elements in the stack
 * 		SLC_STACK_ERASE Makes the stack empty. Basically as if you would POP the COUNT times.
 *
 * @param op Defines which operation the caller wants.
 * @param param On SLC_STACK_PUSH, this is the element to push onto the stack, in case of SLC_STACK_AT, its the index.
 * @return The element at the given stack location in case of SLC_STACK_AT or the count in case of SLC_STACK_COUNT. Can show error!
 */
typedef uint32_t (*stack)(SLC_STACK_OP op, uint32_t param);

/**
 * Function-abstraction for an integer "session-storage".
 *
 * Operations:
 * 		SLC_SESSION_ALLOC allocates parameter amount of memory and returns an accessor index.
 * 		SLC_SESSION_ERASE erase the session storage (all of it)
 * 		SLC_SESSION_GET gets byte at the ith accessor index
 *
 * @param op Defines which operation the caller wants.
 * @param i Used on SESSION_GET and is the accessor index
 * @returns The accessor index in case of ALLOC (0xFFFFFFFF == -1 means error), on get it returns the store BYTE as uint32_t
 */
typedef uint32_t (*session)(SLC_SESSION_OP op, uint32_t i);

/**
 * Function-abstraction for io connectors.
 *
 * Operations:
 *
 * 		SLC_IO_OPEN Opens a PERSISTENT file with the given name. Returns the handle pointer (or NULL on error).
 * 		SLC_IO_CLOSE Closes a PERSISTENT file with the given handle.
 * 		SLC_IO_OPEN_TMP Opens a TEMPORARY file with the given name. Returns the handle pointer.
 * 		SLC_IO_CLOSE_TMP Removes the TEMPORARY file with the given handle.
 * 		SLC_IO_READ Reads a character from the given file handle. Returns pointer to the character that got read.
 * 		SLC_IO_WRITE Writes a character from the given file handle. The 'param' points to the character to write (1 byte)
 * 		SLC_IO_LOCK Locks the given file handle for exclusive reads and writes (others need to use lock/unlock too)
 * 		SLC_IO_UNLOCK Locks the given file handle for exclusive reads and writes (others need to use lock/unlock too)
 * 		SLC_IO_CMD Runs the given command on the operating system. The 'param' is the command (+args) and returned is std output.
 *
 * @param op Defines which operation the caller wants.
 * @param param The name or temporary name or command or the handle pointer parameter depending on op.
 * @returns A handle pointer or pointer to character to read / written or closed/unlocked handle (NULL on errors). Also cmd stdout.
 */
typedef const char* (*ioconn)(SLC_IO_OP op, const char *param);

/**
 * This function runs the main slc engine over a snippet of code.
 *
 * @param code The input source code to interpret / run.
 * @param symbol_table The symbol table to use
 * @param code_stack The code stack (return addresses) to use
 * @param data_stack The data stack (forth-like stack) to use
 * @param insert_stack Used for temporarily expanding the input stream (one word level above) with words
 * @param session_storage Can allocate and use arbitrary memory with this.
 * @param io_connector The engine uses this to open/close pipes/files and write/read them.
 */
void slc(
	const char *code,
	sym symbol_table,
	stack code_stack,
	stack data_stack,
	stack insert_stack,
	session session_storage,
	ioconn io_connector,
	const char *prefix,
	const char *ender,
	const char *varprefix,
) {
	// TODO
}

#ENDIF /* SLC_H */