#!/usr/bin/python3

import shutil
import sqlite3
import os
import getpass
from Whatsapp_Chat_Exporter.utility import WhatsAppIdentifier
from Whatsapp_Chat_Exporter.bplist import BPListReader
try:
    from iphone_backup_decrypt import EncryptedBackup, RelativePath
except ModuleNotFoundError:
    support_encrypted = False
else:
    support_encrypted = True


def extract_encrypted(base_dir, password, identifiers, decrypt_chunk_size):
    print("Trying to decrypt the iOS backup...", end="")
    backup = EncryptedBackup(
        backup_directory=base_dir,
        passphrase=password,
        cleanup=False,
        check_same_thread=False,
        decrypt_chunk_size=decrypt_chunk_size
    )
    print("Done\nDecrypting WhatsApp database...", end="")
    try:
        backup.extract_file(
            relative_path=RelativePath.WHATSAPP_MESSAGES,
            domain_like=identifiers.DOMAIN,
            output_filename=identifiers.MESSAGE
        )
        backup.extract_file(
            relative_path=RelativePath.WHATSAPP_CONTACTS,
            domain_like=identifiers.DOMAIN,
            output_filename=identifiers.CONTACT
        )
    except ValueError:
        print("Failed to decrypt backup: incorrect password?")
        exit(7)
    except FileNotFoundError:
        print("Essential WhatsApp files are missing from the iOS backup.")
        exit(6)
    else:
        print("Done")

    def extract_progress_handler(file_id, domain, relative_path, n, total_files):
        if n % 100 == 0:
            print(f"Decrypting and extracting files...({n}/{total_files})", end="\r")   
        return True

    backup.extract_files(
        domain_like=identifiers.DOMAIN,
        output_folder=identifiers.DOMAIN,
        preserve_folders=True,
        filter_callback=extract_progress_handler
    )
    print(f"All required files are decrypted and extracted.          ", end="\n")
    return backup


def is_encrypted(base_dir):
    with sqlite3.connect(os.path.join(base_dir, "Manifest.db")) as f:
        c = f.cursor()
        try:
            c.execute("""SELECT count()
                    FROM Files
                    """)
        except sqlite3.OperationalError as e:
            raise e  # These error cannot be used to determine if the backup is encrypted
        except sqlite3.DatabaseError:
            return True
        else:
            return False


def extract_media(base_dir, identifiers, decrypt_chunk_size):
    if is_encrypted(base_dir):
        if not support_encrypted:
            print("You don't have the dependencies to handle encrypted backup.")
            print("Read more on how to deal with encrypted backup:")
            print("https://github.com/KnugiHK/Whatsapp-Chat-Exporter/blob/main/README.md#usage")
            return False
        print("Encryption detected on the backup!")
        password = getpass.getpass("Enter the password for the backup:")
        extract_encrypted(base_dir, password, identifiers, decrypt_chunk_size)
    else:
        wts_db = os.path.join(base_dir, identifiers.MESSAGE[:2], identifiers.MESSAGE)
        contact_db = os.path.join(base_dir, identifiers.CONTACT[:2], identifiers.CONTACT)
        if not os.path.isfile(wts_db):
            if identifiers is WhatsAppIdentifier:
                print("WhatsApp database not found.")
            else:
                print("WhatsApp Business database not found.")
            exit()
        else:
            shutil.copyfile(wts_db, identifiers.MESSAGE)
        if not os.path.isfile(contact_db):
            print("Contact database not found.")
            exit()
        else:
            shutil.copyfile(contact_db, identifiers.CONTACT)
        _wts_id = identifiers.DOMAIN
        with sqlite3.connect(os.path.join(base_dir, "Manifest.db")) as manifest:
            manifest.row_factory = sqlite3.Row
            c = manifest.cursor()
            c.execute(
                f"""SELECT count()
                    FROM Files
                    WHERE domain = '{_wts_id}'"""
            )
            total_row_number = c.fetchone()[0]
            print(f"Extracting WhatsApp files...(0/{total_row_number})", end="\r")
            c.execute(f"""SELECT fileID,
                                relativePath,
                                flags,
                                file AS metadata,
                                ROW_NUMBER() OVER(ORDER BY relativePath) AS _index
                        FROM Files
                        WHERE domain = '{_wts_id}'
                        ORDER BY relativePath""")
            if not os.path.isdir(_wts_id):
                os.mkdir(_wts_id)
            row = c.fetchone()
            while row is not None:
                if row["relativePath"] == "":
                    row = c.fetchone()
                    continue
                destination = os.path.join(_wts_id, row["relativePath"])
                hashes = row["fileID"]
                folder = hashes[:2]
                flags = row["flags"]
                if flags == 2:
                    try:
                        os.mkdir(destination)
                    except FileExistsError:
                        pass
                elif flags == 1:
                    shutil.copyfile(os.path.join(base_dir, folder, hashes), destination)
                    metadata = BPListReader(row["metadata"]).parse()
                    creation = metadata["$objects"][1]["Birth"]
                    modification = metadata["$objects"][1]["LastModified"]
                    os.utime(destination, (modification, modification))
                if row["_index"] % 100 == 0:
                    print(f"Extracting WhatsApp files...({row['_index']}/{total_row_number})", end="\r")
                row = c.fetchone()
            print(f"Extracting WhatsApp files...({total_row_number}/{total_row_number})", end="\n")