#include "BracketCheck.h"
#include "Stack.h"

BracketCheck::BracketCheck() { _stack = new Stack(); }
BracketCheck::~BracketCheck() { delete _stack; }

BracketCheck::BracketCheck(const std::string& s) : BracketCheck() {
	for (char x : s) parse(std::string(1, x));
}

void BracketCheck::parse(const std::string& input) {
	if (!_valid) return;
	// match brackets
	switch(input[0]) {
		case '{': case '(': case '[': {
			_stack->push(input);
			break;
		}
		case '}': case ')': case ']': {
			char open_bracket = _stack->pop()[0];
			if (open_bracket == '{' && input[0] == '}') {
				// _stack->pop(); // } is used to close blocks
				break;
			}
			if (open_bracket == '(' && input[0] == ')') break;
			if (open_bracket == '[' && input[0] == ']') break;
			_valid = false;
			break;
		}
	}

	// check block ordering
	switch(input[0]) {
		case 'I': {
			break;
		}
		case 'E': {
			if (_stack->size() == 0) { _valid = false; break; }
			if (_stack->peek()[0] != 'I') _valid = false;
			break;
		}
		case 'D': {
			break;
		}
		case 'W': {
			if (_stack->size() > 0 && _stack->peek()[0] == 'D') { _stack->pop(); }
			break;
		}
	}

	// add blocks to stack
	switch(input[0]) {
		case 'I': case 'E': case 'D': case 'W': {
			_stack->push(input);
		}
	}
}

bool BracketCheck::input_valid() {
	while (_stack->size() > 0) {
		char remainder = _stack->pop()[0];
		switch(remainder) {
			case '{': case '(': case '[': case 'D':
				return false;
		}
	}
	return _valid;
}