#!/usr/bin/env python3

import os
import subprocess
import re
import sys
from argparse import ArgumentParser 

SOLUTIONS = '.solutions.txt'

exs = ['py', 'exe']
sol_pattern = re.compile(r'(\d+)_.+\.(?:{})'.format('|'.join(exs)))

matches = map(sol_pattern.fullmatch, os.listdir('.'))
fs = {int(m.group(1)) : m.group(0) for m in matches if m != None}
solved = sorted(fs.keys())

try:
    with open(SOLUTIONS) as f:
        lines = (line.split() for line in f.read().rstrip().split('\n'))
    solutions = {int(line[0]) : ' '.join(line[1:]) for line in lines}
except FileNotFoundError:
    solutions = dict()

try:
    subprocess.run(['pypy', '--version'],
                   stdout=subprocess.DEVNULL,
                   stderr=subprocess.DEVNULL)

    pypy_installed = True
except FileNotFoundError:
    print('warning : install pypy for faster solving time')
    pypy_installed = False

try:
    subprocess.run(['pypy3', '--version'],
                   stdout=subprocess.DEVNULL,
                   stderr=subprocess.DEVNULL)

    pypy3_installed = True
except FileNotFoundError:
    print('warning : install pypy3 for faster solving time')
    pypy3_installed = False


def print_bar(i, count):
    global print
    step = 1
    while count // step > 80:
        step += 1
    w = count // step
    j = i // step
    bar = '[{}{}] {}/{}'.format('#'*(j), '.'*(w - j), i, count)
    print(bar, end='\r')

    old_print = print
    def new_print(x, *args, **kwargs):
        global print
        print = old_print 
        print(x + ' '*(len(bar) - len(x)), *args, **kwargs)
    print = new_print


def get_cmd(fn):
    ext = fn.split('.')[-1]
    if ext == 'py':
        with open(fn) as f:
            fst_line = f.read().lstrip().split('\n')[0]
        if fst_line[:2] != '#!':
            return 'python '
        shebang = fst_line[2:]
        if pypy_installed:
            return shebang.replace('python', 'pypy') + ' ' 
        if pypy3_installed:
            return shebang.replace('python3', 'pypy3') + ' ' 
        return shebang
    return './' 



def run(fn, cmd=None):
    cmd = get_cmd(fn) if cmd==None else cmd

    proc = subprocess.run(cmd + fn, shell=True,
                          stdout=subprocess.PIPE,
                          stderr=subprocess.PIPE)
    if len(proc.stderr) > 0:
        if 'pypy' in cmd:
            #print('warning : pypy failed. trying cpython', file=sys.stderr)
            #print(proc.stderr)
            return run(fn, cmd = cmd.replace('pypy', 'python'))
        print('error : error while running solution')
        print(proc.stderr.decode('utf-8'), end='')

    return proc.stdout.decode('utf-8').rstrip().split('\n')[-1]
   
def solve_all():
    print('Num    Solution')
    print('---------------')
    for i, x in enumerate(solved, start=1):
        print_bar(i, len(fs))

        f = fs[x]
        r = run(f)
        if x in solutions.keys() and r != solutions[x]:
            wrong_err = 'error : wrong solution for {}, expected {}'
            print(wrong_err.format(x, solutions[x]))
        print('{:>3d}    {}'.format(x, r))

parser = ArgumentParser()
parser.description = \
"""Solves all Project Euler problems with provided solutions.
   A solution is an executable or python file in the same directory as this file,
   with a name of the format XXX_decription.[exe|py], where XXX is the number of
   the problem.
   The problems are available at https://projecteuler.net/"""

parser.add_argument('--get-solutions',
                    action='store_true',
                    help='downloads solutions for user')

def main():
    args = parser.parse_args()
    if args.get_solutions:
        print('Fetching solutions')
    else:
        solve_all()


if __name__ == '__main__':
    main()