#!/usr/bin/python
from imohash.imohash import hashfile as _imohash
import argparse
import hashlib
import os
import psutil
import sqlite3

# https://stackoverflow.com/a/17782753
def file_hash(path, block_size=4096*8):
    '''
    Block size directly depends on the block size of your filesystem
    to avoid performances issues
    Here I have blocks of 4096 octets (Default NTFS)
    '''
    _hash = hashlib.blake2b()
    if os.path.getsize(path) < psutil.virtual_memory().available:
        split = False
    else:
        split = True
    with open(path,'rb') as f:
        if split:
            for chunk in iter(lambda: f.read(block_size), b''):
                _hash.update(chunk)
        else:
            bytes = f.read()
            _hash.update(bytes)
    return _hash.digest()

def hashify(top):
    old_dir = os.getcwd()
    os.chdir(top)
    ret = []
    imo_hashes = set()
    for root,dirs,files in os.walk('.'):
        try:
            for file in files:
                filepath = os.path.join(root,file)
                imohash = _imohash(filepath)
                real_hash = None
                if imohash in imo_hashes:
                    print(filepath)
                    real_hash = file_hash(filepath)
                else:
                    imo_hashes.add(imohash)
                ret.append(
                    (
                        filepath,
                        imohash,
                        real_hash
                    )
                )
        except PermissionError:
            print('Access denied:',root)
        except Exception as e:
            print(e,file)
    os.chdir(old_dir)
    #print(imo_hashes)
    return ret

def __init_database__(path):
    con = sqlite3.connect(path)
    cur = con.cursor()
    cur.execute('CREATE TABLE IF NOT EXISTS `paths` (`path` TEXT, `imohash` BLOB, `blake` BLOB, UNIQUE(`path`, `imohash`, `blake`));')
    con.commit()
    return con

def backup(top,db_path):
    paths = hashify(top)
    con = __init_database__(db_path)
    cur = con.cursor()
    cur.executemany('INSERT OR IGNORE INTO `paths` VALUES (?,?,?);',paths)
    con.commit()

if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument('dir')
    parser.add_argument('-d','--database',default='fs.db')
    args = parser.parse_args()
    __init_database__(args.database)
    backup(args.dir,args.database)