/* link script support */

/*

	label opcode operand



 */

#include <string>
#include <unordered_map>
#include <stdexcept>

#include <cctype>
#include <cstdio>
#include <cstdint>

#include <err.h>

#include "script.h"


/*!re2c
    re2c:define:YYCTYPE = char;
    re2c:yyfill:enable = 0;

    // :-~ includes ; which interferes with comments.
	ident = [:<-~][0-~]*;
	ws = [ \t];
	eof = "\x00";

	number_prefix = [%$0-9];
	ident_prefix = [:-~];
	string_prefix = ['"];
*/

namespace {
	std::unordered_map<std::string, opcode_t> opcodes = {
		#define x(op) { #op, OP_##op },

		#include "ops.h"
		#undef x

		/* aliases */
		{ "AUX", OP_ADR },
		{ "REZ", OP_RES },
		{ "LIN", OP_LNK },
		{ "KIN", OP_KND },
		{ "=",   OP_EQ }
	};

}




static int x_number_operand(const char *YYCURSOR) {
	const char *iter = YYCURSOR;
	// const char *YYMARKER = nullptr;
	uint32_t rv = 0;
	/*!re2c
		* { throw std::invalid_argument("bad operand"); }

		'%' [01]+ {
			++iter;
			for(;iter < YYCURSOR; ++iter) {
				rv <<= 1;
				rv |= *iter - '0';
			}
			goto exit;		
		}

		'$' [A-Fa-f0-9]+ {
			++iter;
			for(;iter < YYCURSOR; ++iter) {
				char c = *iter | 0x20;
				rv <<= 4;
				if (c <= '9') rv |= c - '0';
				else rv |= c - 'a' + 10;
			}
			goto exit;		
		}

		[0-9]+ {
			for(;iter < YYCURSOR; ++iter) {
				rv *= 10;
				rv += *iter - '0';
			}
			goto exit;		
	
		}
	*/
exit:
	char c = *YYCURSOR;
	if (isspace(c) || c == 0) return rv;

	throw std::invalid_argument("bad operand");
}

static std::string x_label_operand(const char *YYCURSOR, bool insensitive) {
	const char *iter = YYCURSOR;
	// const char *YYMARKER = nullptr;
	std::string rv;
	/*!re2c
		* { throw std::invalid_argument("bad operand"); }

		ident {
			rv = std::string(iter, YYCURSOR);
			if (insensitive)
				for (char &c : rv) rv = std::toupper(c);
			goto exit;
		}
	*/
exit:
	char c = *YYCURSOR;
	if (isspace(c) || c == 0) {
		//look up symbol, verify it's an absolute value, etc
		return rv;
	}
	throw std::invalid_argument("bad operand");	
}

static std::string x_string_operand(const char *YYCURSOR) {
	const char *iter = YYCURSOR;
	std::string rv;
	/*!re2c
		* { throw std::invalid_argument("bad operand"); }

		['] [^']* ['] | ["] [^"]* ["] {
			rv = std::string(iter+1, YYCURSOR-1);
			goto exit;
		}

	*/
exit:
	char c = *YYCURSOR;
	if (isspace(c) || c == 0) return rv;
	throw std::invalid_argument("bad operand");	
}

uint32_t number_operand(const char *YYCURSOR, const std::unordered_map<std::string, uint32_t> &map, int flags) {

	const char *cp = YYCURSOR;
	// const char *YYMARKER = nullptr;
	/*!re2c
		* { throw std::invalid_argument("bad operand"); }
		[;*] | eof {
			if (flags & OP_REQUIRED)
				throw std::invalid_argument("missing operand");
			return 0;			
		}

		number_prefix {
			return x_number_operand(cp);
		}

		ident_prefix {
			std::string s = x_label_operand(cp, flags & OP_INSENSITIVE);
			auto iter = map.find(s);
			if (iter == map.end()) throw std::runtime_error("Bad symbol");
			return iter->second;
		}
	*/
}


int ovr_operand(const char *YYCURSOR) {
	int rv = 0;
	const char *YYMARKER = nullptr;

	/*!re2c
		* { throw std::invalid_argument("bad operand"); }
		[;*] | eof {
			return OVR_NONE;
		}
		'ALL' {
			rv = OVR_ALL;
		}
		'OFF' {
			rv = OVR_OFF;
		}
	*/

	char c = *YYCURSOR;
	if (isspace(c) || c == 0) return rv;

	throw std::invalid_argument("bad operand");
}

std::string label_operand(const char *YYCURSOR, int flags) {
	const char *cp = YYCURSOR;
	// const char *YYMARKER = nullptr;
	/*!re2c
		* { throw std::invalid_argument("bad operand"); }
		[;*] | eof {
			if (flags & OP_REQUIRED)
				throw std::invalid_argument("missing operand");
			return std::string();
		}
		ident_prefix {
			return x_label_operand(cp, flags & OP_INSENSITIVE);
		}
	*/
}


std::string path_operand(const char *YYCURSOR, int flags) {
	std::string rv;
	const char *iter = YYCURSOR;
	// const char *YYMARKER = nullptr;
	/*!re2c
		* { throw std::invalid_argument("bad operand"); }

		[;*] | eof {
			if (flags & OP_REQUIRED)
				throw std::invalid_argument("missing operand");
			return rv;
		}
		string_prefix {
			return x_string_operand(iter);
		}

		// don't allow leading quotes, eof, or comment chars
		. [^ \t]* {
			rv = std::string(iter, YYCURSOR);
			goto exit;
		}

	*/

exit:
	char c = *YYCURSOR;
	if (isspace(c) || c == 0) return rv;

	throw std::invalid_argument("bad operand");
}

std::string string_operand(const char *YYCURSOR, int flags) {
	const char *cp = YYCURSOR;
	// const char *YYMARKER = nullptr;
	/*!re2c
		* { throw std::invalid_argument("bad operand"); }

		[;*] | eof {
			if (flags & OP_REQUIRED)
				throw std::invalid_argument("missing operand");
			return std::string();
		}
		string_prefix {
			return x_string_operand(cp);
		}

	*/
}



void no_operand(const char *YYCURSOR) {
	/*!re2c
		* { throw std::invalid_argument("bad operand"); }
		[;*] | eof { return; }
	*/
}


void parse_line(const char *YYCURSOR) {

	label_t label;
	opcode_t opcode = OP_NONE;

	const char *iter = YYCURSOR;
	const char *YYMARKER = nullptr;

	/*!re2c

		* { throw std::invalid_argument("bad label"); }
		[;*] | eof {
			return;
		}
		ws { goto opcode; }
		ident / (ws|eof) {
			label = std::string(iter, YYCURSOR);
			goto opcode;	
		}

	*/


opcode:

	while (isspace(*YYCURSOR)) ++YYCURSOR;
	iter = YYCURSOR;

	/*!re2c

		* { throw std::invalid_argument("bad opcode"); }
		[;*]|eof { return; }

		'=' / (ws|eof) { opcode = OP_EQ; goto operand; }

		[A-Za-z]+ / (ws|eof) {
			size_t l = YYCURSOR - iter;
			if (l > 3) l = 3;
			std::string s(iter, iter + l);
			for (char &c : s) c = std::toupper(c);
			auto iter = opcodes.find(s);
			if (iter == opcodes.end()) {
				throw std::invalid_argument("bad opcode");
			}
			opcode = iter->second;
			goto operand;
		}
	*/

operand:

	while (isspace(*YYCURSOR)) ++YYCURSOR;
	iter = YYCURSOR;

	void evaluate(label_t label, opcode_t opcode, const char *);

	evaluate(label, opcode, YYCURSOR);
}