/*
  Copyright (c) 2015, Matthias Schiffer <mschiffer@universe-factory.net>
  All rights reserved.

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are met:

    1. Redistributions of source code must retain the above copyright notice,
       this list of conditions and the following disclaimer.
    2. Redistributions in binary form must reproduce the above copyright notice,
       this list of conditions and the following disclaimer in the documentation
       and/or other materials provided with the distribution.

  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/


#include "output_source.hpp"

#include <cstring>


namespace solar {

void output_source_t::emit_header_include() {
#ifdef _WIN32
	const char sep = '\\';
#else
	const char sep = '/';
#endif

	const char *slash = std::strrchr(header_filename, sep);
	const char *basename = slash ? slash+1 : header_filename;

	write_line("#include \"", basename, "\"");
}

void output_source_t::emit_type_symbol_value() {
	block_t symbol_value(this, "typedef union ", prefixed("symbol_value"));

	write_line_(variable_t({prefixed("token_value_t"), "token"}));

	for (const auto &nonterm : get_generator()->get_nonterminals()) {
		const std::string &type = get_generator()->get_grammar().get_nonterm_type(nonterm);

		if (!type.empty())
			write_line_(variable_t({type, "symbol_" + nonterm}));
	}

	symbol_value.close_(" ", prefixed("symbol_value_t"));
}

void output_source_t::emit_type_context_state() {
	block_t context_state(this, "typedef struct ", prefixed("context_state"));

	write_line_(variable_t({"unsigned", "state"}));
	write_line_(variable_t({prefixed("symbol_value_t"), "value"}));

	context_state.close_(" ", prefixed("context_state_t"));
}

void output_source_t::emit_type_context() {
	block_t context(this, "struct ", prefixed("context"));

	write_line_(variable_t({"unsigned", "top"}));
	write_line_(variable_t({prefixed("context_state_t"), combine("stack[", stack_size, "]")}));

	context.close_();
}

void output_source_t::emit_types() {
	emit_type_symbol_value();
	write_line();

	emit_type_context_state();
	write_line();

	emit_type_context();
	write_line();
}

void output_source_t::emit_alloc() {
	block_t alloc(this, sig_alloc());
	write_line_(prefixed("context_t *"), "parser = (", prefixed("context_t *"), ")alloc_func(sizeof(", prefixed("context_t"), "))");
	write_line_("parser->top = 0");
	write_line_("parser->stack[0].state = 0");
	write_line_("return parser");
}

void output_source_t::emit_free() {
	block_t free_(this, sig_free());
	write_line_("free_func(parser)");
}

codegen_t::function_t output_source_t::sig_reduction(unsigned rule_id) {
	const rule_t &rule = get_generator()->get_grammar().rules[rule_id];
	const item_t &item = rule.item;
	const std::string &type = get_generator()->get_grammar().get_nonterm_type(item.get_lhs());

	function_t sig("static inline " + (type.empty() ? "void" : type), prefixed(combine("reduce_", rule_id)));

	for (unsigned i = 0; i < rule.variables.size(); i++) {
		const auto &var = rule.variables[i];

		if (var.first.empty())
			continue;

		sig.add_arg(get_generator()->get_grammar().get_type(item.get_rhs()[i]), var.first);
	}

	for (const auto &arg : get_generator()->get_grammar().extra_args)
		sig.add_arg(arg);

	return sig;
}

void output_source_t::emit_reduction(unsigned rule_id) {
	function_t sig = sig_reduction(rule_id);
	write_line(sig, " {", get_generator()->get_grammar().rules[rule_id].action, "}");
	write_line();
}

void output_source_t::emit_reductions() {
	const auto &rules = get_generator()->get_grammar().rules;

	for (size_t i = 0; i < rules.size(); i++) {
		if (!rules[i].action.empty())
			emit_reduction(i);
	}
}

void output_source_t::emit_gotos(const std::string &lhs) {
	std::map<unsigned, std::set<unsigned>> gotos;

	for (size_t state = 0; state < get_generator()->get_state_count(); state++) {
		auto it = get_generator()->get_gotos().find({state, lhs});
		if (it == get_generator()->get_gotos().end())
			continue;

		std::set<unsigned> &states = gotos.insert({it->second, std::set<unsigned>()}).first->second;
		states.insert(state);
	}

	if (gotos.size() == 1) {
		write_line_("parser->stack[++parser->top].state = ", gotos.begin()->first);
	}
	else {
		block_t switch_state(this, "switch (parser->stack[parser->top].state)");

		for (const auto &entry : gotos) {
			for (unsigned state : entry.second)
				write_case(state);
			write_line_("parser->stack[++parser->top].state = ", entry.first);
			write_line_("break");
			write_line();
		}
	}
}

void output_source_t::emit_states() {
	for (size_t state = 0; state < get_generator()->get_state_count(); state++) {
		write_case(state);
		emit_state(state);
		write_line_("break");
		write_line();
	}
}

void output_source_t::emit_do_push() {
	function_t do_push_sig("static int", prefixed("do_push"));
	do_push_sig.add_arg(prefixed("context_t *"), "parser");
	do_push_sig.add_arg("int", "token");
	for (const auto &arg : get_generator()->get_grammar().extra_args)
		do_push_sig.add_arg(arg);

	block_t do_push(this, do_push_sig);

	write_line_(prefixed("symbol_value_t"), " result");
	write_line();

	block_t while_1(this, "while (1)");
	block_t switch_state(this, "switch (parser->stack[parser->top].state)");

	emit_states();
}

void output_source_t::emit_push() {
	block_t push(this, sig_push());
	write_line_("int ret = parse_do_push(parser, token, grammar)");
	write_line();
	write_line("if (ret > 0)");
	_write_line_("parser->stack[parser->top-1].value.token = *value");
	write_line();
	write_line_("return ret");

}

void output_source_t::write() {
	emit_header_include();
	write_line();

	if (!get_generator()->get_grammar().source_block.empty()) {
		write_line(get_generator()->get_grammar().source_block);
		write_line();
	}

	if (!get_generator()->get_grammar().ns.empty()) {
		for (const std::string &ns : get_generator()->get_grammar().ns)
			write_line("namespace ", ns, " {");

		write_line();
	}

	emit_types();
	write_line();

	emit_alloc();
	write_line();
	emit_free();
	write_line();
	write_line();

	emit_reductions();
	write_line();

	emit_do_push();
	write_line();

	emit_push();

	if (!get_generator()->get_grammar().ns.empty()) {
		write_line();

		for (size_t i = 0; i < get_generator()->get_grammar().ns.size(); i++)
			write_line("}");
	}
}

}