#ifndef _AST_EXPR_EXPR_H_
#define _AST_EXPR_EXPR_H_

#include "../ctx.h"
#include "../node.h"

#include <blue/core/queue.h>

struct ivy_ast_node;
struct ivy_ast_msg_node;

enum expr_type {
	EXPR_TYPE_NONE = 0,
	/* if-else, while/for, match, etc (any expression that ends with an
	 * 'end' keyword */
	EXPR_TYPE_STMT,
	/* arithmetic and message-sending expressions (any expression that ends
	 * implicitly or with an expression separator */
	EXPR_TYPE_ARITH,
};

enum expr_subtype {
	EXPR_SUBTYPE_NONE = 0,
	/* generic parenthesis-enclosed arithmetic expressions */
	EXPR_SUBTYPE_PAREN,
	/* any kind of message */
	EXPR_SUBTYPE_MSG,
	/* keyword messages */
	EXPR_SUBTYPE_KEYWORD_MSG,
	/* expression delimited by labels */
	EXPR_SUBTYPE_KEYWORD_ARG,
	/* complex messages */
	EXPR_SUBTYPE_COMPLEX_MSG,
	/* message cascade operation */
	EXPR_SUBTYPE_CASCADE,
};

enum expr_component {
	EXPR_CMP_NONE = 0,
	EXPR_CMP_OPERATOR,
	EXPR_CMP_OPERAND,
	EXPR_CMP_MSG,
};

struct expr_parser_state {
	struct parser_state s_base;
	enum expr_type s_type;
	enum expr_subtype s_sub_type;

	/* this is a return statement (prefixed with a caret) */
	bool s_return;

	/* for arithmetic expressions, this records whether the previous
	 * component (either a token or parenthesised group of tokens) is an
	 * operator, operand, or message */
	enum expr_component s_prev_component;
	/* the token type/keyword type/symbol type of the last token that was
	 * encountered */
	unsigned int s_prev_token;
	/* if this is an arithmetic expression, this variable is the depth
	 * of parentheses that this sub-expression is at */
	unsigned int s_paren_depth;

	/* if this expression is parsing a sub-component of a larger expression,
	 * the depth of the expression is recorded here. */
	unsigned int s_subexpr_depth;

	/* when this is set, the expression will be terminated when the
	 * specified token is encountered. the token that terminated the
	 * expression will not be consumed. */
	unsigned int s_terminator;

	b_queue s_output_queue;
	b_queue s_operator_stack;

	/* these variables are for keyword-message expressions */
	struct ivy_ast_node *s_recipient;
	struct ivy_ast_msg_node *s_msg;
	b_queue s_labels;

	union {
		/* for keyword-messages, this is a list of arg values. */
		b_queue s_args;
		/* for cascade operators, this is a list of messages to send to the recipient. */
		b_queue s_cascade_msg;
	};
};

/* general functions */

extern struct token_parse_result expr_finalise(
	struct ivy_parser *ctx, struct expr_parser_state *state,
	enum ivy_operator_precedence min_precedence, struct ivy_ast_node **expr);
extern struct token_parse_result expr_finalise_and_return(
	struct ivy_parser *ctx, struct expr_parser_state *state);

/* arithmetic parser callbacks */

extern void arith_push_operator(
	struct expr_parser_state *state, struct ivy_ast_node *node);
extern enum ivy_status arith_push_operand(
	struct expr_parser_state *state, struct ivy_token *tok);

extern enum ivy_status arith_add_child(
	struct parser_state *parent, struct ivy_ast_node *child);

extern struct token_parse_result arith_parse_ident(
	struct ivy_parser *ctx, struct ivy_token *tok);
extern struct token_parse_result arith_parse_operand(
	struct ivy_parser *ctx, struct ivy_token *tok);
extern struct token_parse_result arith_parse_operator(
	struct ivy_parser *ctx, struct ivy_token *tok);
extern struct token_parse_result arith_parse_label(
	struct ivy_parser *ctx, struct ivy_token *tok);
extern struct token_parse_result arith_parse_left_paren(
	struct ivy_parser *ctx, struct ivy_token *tok);
extern struct token_parse_result arith_parse_right_paren(
	struct ivy_parser *ctx, struct ivy_token *tok);
extern struct token_parse_result arith_parse_semicolon(
	struct ivy_parser *ctx, struct ivy_token *tok);
extern struct token_parse_result arith_parse_dot(
	struct ivy_parser *ctx, struct ivy_token *tok);
extern struct token_parse_result arith_parse_bang(
	struct ivy_parser *ctx, struct ivy_token *tok);
extern struct token_parse_result arith_parse_caret(
	struct ivy_parser *ctx, struct ivy_token *tok);
extern struct token_parse_result arith_parse_comma(
	struct ivy_parser *ctx, struct ivy_token *tok);
extern struct token_parse_result arith_parse_equal_right_angle(
	struct ivy_parser *ctx, struct ivy_token *tok);
extern struct token_parse_result arith_parse_in(
	struct ivy_parser *ctx, struct ivy_token *tok);
extern struct token_parse_result arith_parse_do(
	struct ivy_parser *ctx, struct ivy_token *tok);

/* statement parser callbacks */

extern struct token_parse_result stmt_parse_for(
	struct ivy_parser *ctx, struct ivy_token *tok);
extern struct token_parse_result stmt_parse_while(
	struct ivy_parser *ctx, struct ivy_token *tok);
extern struct token_parse_result stmt_parse_match(
	struct ivy_parser *ctx, struct ivy_token *tok);
extern struct token_parse_result stmt_parse_if(
	struct ivy_parser *ctx, struct ivy_token *tok);
extern struct token_parse_result stmt_parse_then(
	struct ivy_parser *ctx, struct ivy_token *tok);
struct token_parse_result stmt_parse_else(
	struct ivy_parser *ctx, struct ivy_token *tok);
struct token_parse_result stmt_parse_end(
	struct ivy_parser *ctx, struct ivy_token *tok);

#endif