#!/usr/bin/python3
# -*- coding: utf-8 -*-

"""
:mod: module
:author: `Éric W`
:date: 2016, october

"""

def usage():
    print('Usage: {:s} <bdd> <n>'.format(sys.argv[0]))
    print('where')
    print('\t<bdd> is a text file whose lines are valid sudoku grids descriptions')
    print('\t<n> is the line number to extract in file <bdd>')
    print('\nExample: with the grid on line 7 of the file bdd/sudokus.bdd')
    print('$ {:s} bdd/sudokus.bdd 7'.format(sys.argv[0]))
    exit(1)
    
if __name__ == '__main__':
    import sys
    import sudoku_grid, sudoku_solver

    if len(sys.argv) != 3:
        print('Argument missing.')
        usage()
    else:
        filename = sys.argv[1]
        try:
            n = int(sys.argv[2])
        except ValueError:
            print('Second argument must be an integer >=0.')
            usage()
        try:
            with open(filename, 'r') as input:
                lines = input.readlines()
        except FileNotFoundError:
            print('No such file {:s}'.format(filename))
            usage()
        try:
            line = lines[n].rstrip('\n')
        except IndexError:
            print('File {:s} has no line number {:d}.'.format(filename, n))
            usage()
        strgrid = line.split(':')[-1]
        try:
            grid = sudoku_grid.SudokuGrid(strgrid)
        except sudoku_grid.SudokuGridError:
            print("Line number {:d} of file {:s} has no valid sudoku's grid description".format(n, filename,))
            usage()
        print('Sudoku to solve')
        grid.pretty_print()
        sols = sudoku_solver.solve(grid)
        nb_sols = len(sols)
        print('Number of solution(s): {:d}'.format(nb_sols))
        print('--')
        for i in range(nb_sols):
            print('Solution {:d}'.format(i + 1))
            sols[i].pretty_print()
            print('--')
        
    exit(0)