From 860a237faae4c46b07a5c23792a8285563e0d516 Mon Sep 17 00:00:00 2001
From: "David Vereb (Home)" <dvereb@dvereb.com>
Date: Mon, 1 Apr 2019 17:14:30 -0500
Subject: [PATCH] Easier to understand number generation for hard problems. 
 Initial support for input and checking correctness.

---
 Problem.cpp | 72 ++++++++++++++++++++++++++++++++++++++---------------
 Problem.h   | 15 ++++++++++-
 2 files changed, 66 insertions(+), 21 deletions(-)

diff --git a/Problem.cpp b/Problem.cpp
index e6c9d13..9f08507 100644
--- a/Problem.cpp
+++ b/Problem.cpp
@@ -2,6 +2,7 @@
 
 #include <cmath>
 #include <locale.h>
+#include <syslog.h>
 
 bool Problem::seeded = false;
 
@@ -83,17 +84,6 @@ void Problem::GenerateNumbers(PROBLEM_TYPE type, unsigned short max_digits)
 			number_bottom += temp_number_bottom * (pow(10, digit));
 		}
 		break;
-	case HARD_ADDITION:
-		for(auto digit = 0; digit < digits; ++digit)
-		{
-			unsigned short temp_number_top = rand() % 10;
-			unsigned short temp_number_bottom = rand() % 10;
-
-			// Place into correct digit posititon:
-			number_top += temp_number_top * (pow(10, digit));
-			number_bottom += temp_number_bottom * (pow(10, digit));
-		}
-		break;
 	case EASY_SUBTRACTION:
 		for(auto digit = 0; digit < digits; ++digit)
 		{
@@ -110,16 +100,13 @@ void Problem::GenerateNumbers(PROBLEM_TYPE type, unsigned short max_digits)
 			number_bottom += temp_number_bottom * (pow(10, digit));
 		}
 		break;
+	case HARD_ADDITION:
+		number_top    = rand() % int(pow(10, digits));
+		number_bottom = rand() % int(pow(10, digits));
+		break;
 	case HARD_SUBTRACTION:
-		for(auto digit = 0; digit < digits; ++digit)
-		{
-			unsigned short temp_number_top = rand() % 10;
-			unsigned short temp_number_bottom = rand() % 10;
-
-			// Place into correct digit posititon:
-			number_top += temp_number_top * (pow(10, digit));
-			number_bottom += temp_number_bottom * (pow(10, digit));
-		}
+		number_top    = rand() % int(pow(10, digits));
+		number_bottom = rand() % int(pow(10, digits));
 		// NOTE(dev): don't allow negative numbers:
 		if(number_bottom > number_top)
 		{
@@ -152,3 +139,48 @@ void Problem::GenerateWindow(unsigned win_x, unsigned win_y)
 	if(!win)
 		return;
 }
+
+int Problem::Input() const
+{
+	int rtn = 0;
+	try {
+		rtn = std::stoi(input.c_str());
+	} catch (const std::exception &e) {
+		syslog(LOG_USER|LOG_DEBUG, "%s:%d:%s Invalid std::stoi: %s",
+		       __FILE__,__LINE__,__PRETTY_FUNCTION__,e.what());
+		exit(-1); // INVALID INPUT!!!
+	}
+	return rtn;
+}
+
+void Problem::Input(char character)
+{
+	// TODO(dev): ASSERT
+	if(character < '0' || character > '9')
+		exit(-1);
+
+	if(input_style == INPUT_STYLE::INPUT_PREPEND)
+		input = std::to_string(character) + input;
+	else
+		input += std::to_string(character);
+}
+
+bool Problem::Correct() const
+{
+	// NOTE(dev): I know I don't need "break;", but it just makes me happier knowing they're there.
+	switch(problem_type)
+	{
+	case EASY_ADDITION:
+	case HARD_ADDITION:
+		return number_top + number_bottom == Input();
+		break;
+	case EASY_SUBTRACTION:
+	case HARD_SUBTRACTION:
+		return number_top - number_bottom == Input();
+		break;
+	};
+
+	// TODO(dev): Assert that all conditions are handled!
+	exit(-1);
+	return false;
+}
diff --git a/Problem.h b/Problem.h
index 80fb105..06bed60 100644
--- a/Problem.h
+++ b/Problem.h
@@ -1,13 +1,14 @@
 #ifndef DVEREB_PROBLEM_H
 #define DVEREB_PROBLEM_H
 
+#include <string>
 #include <cstdlib>
 #include <ncurses.h>
 
 enum PROBLEM_TYPE
 {
 	// NOTE(dev): EASY means each digit can be handled without carryover.
-	//             e.g. 33 + 46 is easy because 6+3 < 10 and 3+4 is < 10.
+	//             e.g. 33 + 46 is easy because 3+6 < 10 and 3+4 is < 10.
 	//            HARD means you might have to carry over.
 	//             e.g. 33 + 97 is hard because 7 + 3 = 10, carry the 1, 9 + 3 + 1 = 13, 130.
 	EASY_ADDITION = 1,
@@ -16,6 +17,12 @@ enum PROBLEM_TYPE
 	HARD_SUBTRACTION,
 };
 
+enum INPUT_STYLE
+{
+	INPUT_PREPEND = 1,
+	INPUT_APPEND,
+};
+
 class Problem
 {
 public:
@@ -23,6 +30,8 @@ public:
 	~Problem();
 
 	void Draw(bool selected);
+	void Input(char character);
+	bool Correct() const;
 
 private:
 	Problem() = delete;
@@ -35,6 +44,10 @@ private:
 	int number_top;
 	int number_bottom;
 
+	INPUT_STYLE input_style = INPUT_STYLE::INPUT_PREPEND;
+	int Input() const;
+	std::string input;
+
 	// Helper Functions:
 	void GenerateNumbers(PROBLEM_TYPE type, unsigned short max_digits);
 	void GenerateWindow(unsigned win_x, unsigned win_y);