-- Select the first cell in the set {A1 : I9}.
-- Check if the cell is free.
-- If that cell is not free, chose the next cell in the set {A1 : I9}.
-- Repeat until you find an available cell.
-- Set the available cell to be the active cell.
-- Select with the lowest number if the set {1 : 9}.
-- Check if that number is used in the current “row”, “column” or “3 x 3 cell”.
-- If the number is used, chose the next lowest number and see if that is available.
-- Repeat until you find an available number.
-- Once you find an available number, check if there is more than one available number.
-- If there is, populate the active cell with the lowest of them.
-- If there is not, populate the active cell with the available number.
-- If there is no available number, backtrack to the last place where you have more than 1 available number and use the next highest number.
-- Repeat until there are no available cells.


with ada.text_io, ada.integer_text_io, ada.command_line;
use ada.text_io, ada.integer_text_io, ada.command_line;



procedure sudoku is
	subtype counter is integer range 1..9;
	subtype row is integer range 1..9;
	subtype col is integer range 1..9;
	type board is array (row, col) of integer;
	input_file: file_type;
	placeholder: integer;

	puzzle: board := (others=>(others=> 0));


	function handle_arguments return boolean is
	begin
		if argument_count <1 then
			put("Please enter in atleast one argument into Cmd line!");
			return false;
		end if;
		if argument_count =1 then
			begin
			open(file=>input_file, name=>argument(1), mode=>in_file);

			exception
			when name_error=>
				put("File name provided will not open..");
				return false;
			end;
		end if;
		return true;
	end handle_arguments;

--Check each row
	function check_row (data: in board; target_row: in row)
	return boolean is
		seen: array (row) of boolean :=(others=> false);
		current_value: integer;
	begin
		for c in Data'range (2) loop
		current_value := data(target_row, c);
			if current_value in row then
				if seen(current_value) then
					return false;
				end if;
				seen(current_value) := true;
			end if;
		end loop;
		return true;
	end check_row;

--Check each col
	function check_col (data: in board; target_col: in col)
	return boolean is
		seen: array (col) of boolean :=(others=>false);
		current_value: integer;
	begin
		for r in data'range (1) loop
			current_value:= data(target_col, r);
			if current_value in col then
				if seen(current_value) then
					return false;
				end if;
				seen(current_value):= true;
			end if;
		end loop;
		return true;
	end check_col;

--Check each box
	function check_box (data: in board; target_row: in row; target_col: in col)
	return boolean is
		seen: array(counter) of boolean := (others=> false);
		current_value: integer;
		row_offset: constant integer:= ((target_row-1) /3) *3;
		col_offset: constant integer:= ((target_col-1) /3) *3;
	begin
		for box_row in 1..3 loop
			for box_col in 1..3 loop
				current_value := data(row_offset + box_row, col_offset + box_col);
				if current_value in counter then
					if seen(current_value) then
						return false;
					end if;
					seen (current_value):= true;
				end if;
			end loop;
		end loop;
		return true;
	end check_box;

--Check to make sure each value is valid
	-- function valid_value (data: in board) return boolean is
		-- result : boolean:= true;
	-- begin
		-- for r in data'range (1) loop
			-- result:= result and check_row(data,r);
--Solve
	--procedure solve (data: in out board) is
	--	solved: boolean := false;


--Ouput board
		procedure output_board (data: in board) is
		begin
			for r in data'range (1) loop
				for c in data'range (2) loop
					put(data(r,c));
				end loop;
				new_line;
			end loop;
		end output_board;

begin
	--Handling the input arguments and opening
	if handle_arguments = true then
	put("Original puzzle: ");
	new_line;
	for r in row loop
		put("|");
		for c in col loop
			get(input_file, placeholder);
				if placeholder not in counter then
					puzzle(r,c):= 0;
				else
					puzzle(r,c) := placeholder;
				end if;
			put(placeholder);
		end loop;
		put("|");
		new_line;
	 end loop;

	end if;
end sudoku;