#!/usr/bin/env python3
import sys
import os
import subprocess
import re
import readline


class c:
    black = ''
    red = '\033[0;31m'
    b_red = '\033[1;31m'
    yellow = '\033[1;33m'
    green = '\033[0;32m'
    b_green = '\033[1;32m'
    cyan = '\033[0;36m'
    b_cyan = '\033[1;36m'
    purple = '\033[1;35m'
    blue = '\033[0;34m'
    b_blue = '\033[1;34m'
    white = '\033[1;37m'
    end = '\033[0m'


def validate_filename(filename):
    if re.match(r'^[\w.\-]{1,100}', filename):
        return True
    return False


def validate_path(path):
    if not path[0] in ['.','~','/']:
        path = './{}'.format(path)
    temp = path.split('/')
    temp.pop()
    temp = '/'.join(temp)
    loc = subprocess.run(['ls',temp], stdout=subprocess.PIPE, stderr=subprocess.PIPE)

    if loc.returncode > 0:
        return False

    if temp[-1] == '/':
        temp = temp[:-1]
    if filepath:
        temp = temp + '/' + path.split('/')[-1]
    return temp


def chalk(path):
    fn = path.split('/')[-1]
    valid_fn = validate_filename(fn)

    if not valid_fn:
        print('Invalid filename')
        sys.exit(2)

    valid_path = validate_path(path)
    if not valid_path:
        print('Invalid path')
        sys.exit(2)

    header = "{:7}      5   10   15   20   25   30   35   40   45   50   55   60   65\n{:7}  ....|....|....|....|....|....|....|....|....|....|....|....|....|".format(' ',' ')

    helptext = [
        "",
        "{}Commands are entered as the only entry for their row:{}".format(c.yellow, c.end),
        "  . - Finish writing/exit, will prompt for save",
        " !? - Print this help message",
        " !d - Display the contents of the file",
        " !# - Rewrite a line, # is replaced by line number e.g. !27",
        " !x - Delete line(s), prompt will request line or range",
        " !i - Insert line(s), prompt will request start point and optional quantity",
        ""
    ]

    content = []

    if os.path.exists(valid_path):
        with open(valid_path,'r') as f:
            content = f.read().split('\n')

    print('\n   Chalk 0.8 by sloum')
    print('\n{}   Writing:{} {}{}'.format(c.yellow, c.white, fn, c.end))
    print("   For a command list, enter {}!?\n{}".format(c.green, c.end))
    print(header)
    while True:
        ln = input('{:6} {}>{} '.format(len(content), c.yellow, c.end))
        if ln == '.':
            break
        elif ln == '!?':
            print('')
            for x in helptext:
                print('{:8} {}'.format(' ',x))
            print('')
            print(header)
        elif ln == '!d':
            print('')
            for i, x in enumerate(content):
                print('{:6} - {}{}{}'.format(i, c.green, x, c.end))
            print('')
            print(header)
        elif ln == '!x':
            print('\n{:8} {}Enter line to delete, for a range enter the start and\n{:8} end separated by a space. To cancel, enter -1.\n{:8} Deletion cannot be undone. Be careful.{}'.format(' ', c.cyan, ' ', ' ', c.end))
            delete = input('{:6} {}>{} '.format(' ', c.b_red, c.end))
            entry = delete.split(' ')
            try:
                beg = int(entry[0])
                end = beg + 1
                if len(entry) > 1:
                    end = int(entry[1]) + 1
                if beg < 0:
                    continue
                content = content[:beg] + content[end:]
            except:
                print('{}{:8} Invalid entry{}'.format(c.red, ' ', c.end))
            print('')
        elif ln == '!i':
            print('\n{:8} {}Enter the line number that you want the new line(s) to\n{:8} appear after.To insert multiple lines enter the starting\n{:8} point and the number of lines separated by a space. To cancel, enter -1{}'.format(' ', c.cyan, ' ', ' ', c.end))
            insert = input('{:6} {}>{} '.format(' ', c.b_green, c.end))
            entry = insert.split(' ')
            try:
                beg = int(entry[0]) + 1
                count = 1
                if len(entry) > 1:
                    count = int(entry[1])
                if beg < 0 or count < 1:
                    continue
                while count > 0:
                    content.insert(beg,'')
                    count -= 1
            except:
                print('{}{:8} Invalid entry{}'.format(c.red, ' ', c.end))
            print('')
        elif re.match(r'^\!\d+$',ln):
            try:
                row = int(ln[1:])
                print('{:8} {}Type !c to cancel line edit{}'.format(' ', c.yellow, c.end))
                print('{:>6} : {}'.format('old', content[row]))
                newln = input('{:6} {}>{} '.format(row, c.b_blue, c.end))
                if newln == '!c':
                    print('{:8} Cancelled...'.format(' '))
                else:
                    content[row] = newln
            except:
                print('{}{:8} Invalid entry!{}'.format(c.b_red, ' ', c.end))
            print('')
            print(header)
        else:
            content.append(ln)

    confirmation = ''
    while confirmation.lower() not in ['y','yes','n','no']:
        confirmation = input('{}Save {}?{} (Y/n) '.format(c.b_green, fn, c.end))
        if confirmation.lower()[0] == 'y':
            print('{}saving...{}'.format(c.white, c.end))
            text = '\n'.join(content)
            try:
                with open(valid_path, 'w') as f:
                    f.write(text)
                print('Done.\n')
            except:
                print('{}   You do not have permission to write to this file.{}'.format(c.red, c.end))
        else:
            print('{}exiting...{}\n'.format(c.white, c.end))


if __name__ == '__main__':
    args = sys.argv
    if len(args) < 2:
        print('Incorrect number of arguments.')
        sys.exit(1)
    filepath = args[1]
    chalk(filepath)