#!/usr/bin/env python3

# requires fusepy package

import os
import sys
import errno
import stat
import time
import subprocess
from datetime import datetime
from fuse import FUSE, FuseOSError, Operations

class GlitterFS(Operations):
    
    def __init__(self):
        self.files = {}
        self.data = {}
        self.fd = 0 # file descriptor

        now = time.time()
        self.files['/'] = {
            'st_mode': stat.S_IFDIR | 0o755, # dir and permissions in octal
            'st_ctime': now, # creation time
            'st_mtime': now, # modification time
            'st_atime': now, # access time
            'st_nlink': 2,  # number of hard links, for dirs: . and ..
            'st_size': 0 # size in bytes
        }
        

    def getattr(self, path, fh=None):
        if path not in self.files:
            raise FuseOSError(errno.ENOENT)
        return self.files[path]


    # generator - based
    def readdir(self, path, fh):
        yield '.'
        yield '..'

        if path == '/':
            path = ''  # For easier concatenation

        for name in self.files:
            if name != '/' and name.startswith(path + '/') \
            and '/' not in name[len(path) + 1:]: # only base files of directory
                yield name[len(path) + 1:]

    
    def mkdir(self, path, mode):
        now = time.time()
        self.files[path] = {
            'st_mode': stat.S_IFDIR | mode,
            'st_ctime': now,
            'st_mtime': now,
            'st_atime': now,
            'st_nlink': 2,
            'st_size': 0
        }
        # Update parent's link count
        parent = os.path.dirname(path)
        self.files[parent]['st_nlink'] += 1
        return 0

    
    def open(self, path, flags):
        self.fd += 1
        return self.fd


    def create(self, path, mode, fi=None):
        now = time.time()
        self.files[path] = {
            'st_mode': stat.S_IFREG | mode,
            'st_ctime': now,
            'st_mtime': now,
            'st_atime': now,
            'st_nlink': 1,
            'st_size': 37000, # will not call 'read' on size = 0
        }
        self.fd += 1

        # Load file Contents
        filename = os.path.basename(path)
        filename = filename.replace(" ", "%20")

        imgname = subprocess.run(
            "curl -L " +
            f"'https://www.gigaglitters.com/procesing.php?text={filename}' " +
            r"| sed -nE 's/.*<img src=\/created\/(.*.gif)>.*/\1/p'",
            shell=True, capture_output=True).stdout.decode('utf-8').strip()

        out = subprocess.run(
            f"curl --output - 'https://www.gigaglitters.com/created/{imgname}'",
            shell=True, capture_output=True).stdout

        self.data[path] = out

        return self.fd


    def read(self, path, size, offset, fh):
        print(offset, size, fh)
        return self.data[path][offset:offset+size]


    def write(self, path, data, offset, fh):
        return len(data)
    

    def truncate(self, path, length, fh=None):
        pass


    def unlink(self, path):
        if path in self.files:
            del self.files[path]
        if path in self.data:
            del self.data[path]


    def rmdir(self, path):
        # Check if directory is empty
        for name in self.files:
            if name != path and name.startswith(path + '/'):
                raise FuseOSError(errno.ENOTEMPTY)
        
        # Remove directory and update parent
        parent = os.path.dirname(path)
        self.files[parent]['st_nlink'] -= 1
        del self.files[path]
    

    def chmod(self, path, mode):
        if path in self.files:
            self.files[path]['st_mode'] = (self.files[path]['st_mode'] & ~0o777) | mode
            self.files[path]['st_mtime'] = time.time()

    
    def utimens(self, path, times=None):
        if path in self.files:
            now = time.time()
            atime, mtime = times if times else (now, now)
            self.files[path]['st_atime'] = atime
            self.files[path]['st_mtime'] = mtime


def main(mountpoint):
    FUSE(GlitterFS(), mountpoint, nothreads=True, foreground=True)


if __name__ == '__main__':
    if len(sys.argv) != 2:
        print(f"Usage: {sys.argv[0]} <mountpoint>")
        sys.exit(1)
    
    mountpoint = sys.argv[1]
    print(f"Mounting synthetic filesystem at {mountpoint}")
    main(mountpoint)