# -*- coding: utf-8 -*-
# ===================================================
# ==================== META DATA ===================
# ==================================================
__author__ = "Daxeel Soni"
__url__ = "https://daxeel.github.io"
__email__ = "daxeelsoni44@gmail.com"
__license__ = "MIT"
__version__ = "0.1"
__maintainer__ = "Daxeel Soni"

# ==================================================
# ================= IMPORT MODULES =================
# ==================================================
import click
import urllib
import json
from blockchain.chain import Block, Blockchain
from colorama import Fore, Back, Style

# ==================================================
# ===== SUPPORTED COMMANDS LIST IN BLOCKSHELL ======
# ==================================================
SUPPORTED_COMMANDS = [
    'dotx',
    'allblocks',
    'getblock',
    'help',
    'modify',
    'verify',
]

def printLogo():
    print("""
  ____    _                  _       _____   _              _   _
 |  _ \  | |                | |     / ____| | |            | | | |
 | |_) | | |   ___     ___  | | __ | (___   | |__     ___  | | | |
 |  _ <  | |  / _ \   / __| | |/ /  \___ \  | '_ \   / _ \ | | | |
 | |_) | | | | (_) | | (__  |   <   ____) | | | | | |  __/ | | | |
 |____/  |_|  \___/   \___| |_|\_\ |_____/  |_| |_|  \___| |_| |_|

 > A command line utility for learning Blockchain concepts.
 > Type 'help' to see supported commands.
 > Project by Daxeel Soni - https://daxeel.github.io

    """)

def startShell():
    """
        Method to start Blockshell CLI
    """
    printLogo()
    # Start blockshell shell
    while True:
        cmd = input("[BlockShell] $ ")
        processInput(cmd)

# Init blockchain
coin = Blockchain()

# Create group of commands
@click.group()
def cli():
    """
        Create a group of commands for CLI
    """
    pass

# ==================================================
# ============= BLOCKSHELL CLI COMMAND =============
# ==================================================
@cli.command()
@click.option("--difficulty", default=3, help="Define difficulty level of blockchain.")
def init(difficulty):
    """Initialize local blockchain"""

    coin.writeBlocks()
    # Set difficulty of blockchain
    coin.difficulty = difficulty

    # Start blockshell shell
    startShell()

@cli.command()
@click.argument("filename", type=click.Path())
@click.option("--difficulty", default=3, help="Define difficulty level of blockchain.")
def load(filename, difficulty):
    """Load blockchain from file"""

    # Load blockchain from file
    coin.loadBlocks(filename)

    # Set difficulty of blockchain
    coin.difficulty = difficulty

    printSuccess(f"Blockchain loaded successfully. {len(coin.chain)} blocks loaded.")
    # Start blockshell shell
    startShell()

# Process input from Blockshell shell
def processInput(cmd):
    """
        Method to process user input from Blockshell CLI.
    """
    splitted = cmd.split(" ")
    userCmd = splitted[0]
    if len(splitted) and len(userCmd) > 0:
        if userCmd in SUPPORTED_COMMANDS:
            globals()[userCmd](splitted[1:])
        else:
            # error
            msg = "Command not found. Try help command for documentation"
            throwError(msg)


# ==================================================
# =========== BLOCKSHELL COMMAND METHODS ===========
# ==================================================
def dotx(args):
    """
        Do Transaction - Method to perform new transaction on blockchain.
    """
    print("Doing transaction...")
    coin.addBlock(Block.fromValues(int(args[0]), args[1], args[2], args[3]))

def allblocks(cmd):
    """
        Method to list all mined blocks.
    """
    print("")
    for eachBlock in coin.chain:
        print(eachBlock.hash)
    print("")

def getblock(args):
    """
        Method to fetch the details of block for given hash.
    """
    blockHash = args[0]
    for eachBlock in coin.chain:
        if eachBlock.hash == blockHash:
            print("")
            print(eachBlock.__dict__)
            print("")

def help(cmd):
    """
        Method to display supported commands in Blockshell
    """
    print("Commands:")
    print("   dotx <uid> <mail> <firstname> <lastname>                    Create new transaction")
    print("   allblocks                                                   Fetch all mined blocks in blockchain")
    print("   getblock <block hash>                                       Fetch information about particular block")
    print("   modify <block hash> <uid> <mail> <firstname> <lastname>     Modify a particular block keeping blockchain validity")
    print("   verify                                                      Verify blockchain integrity")

def modify(args):
    """
        Method to modify any block in blockchain.
    """
    if coin.modifyBlock(args[0], args[1], args[2], args[3], args[4]):
        printSuccess("Block modified successfully!")
    else:
        throwError("Block modification failed!")

def verify(cmd):
    """
        Method to verify the validity of blockchain.
    """
    chain_valid = coin.isChainValid()
    if chain_valid == 0:
        printSuccess("Blockchain is valid!")
    else:
        throwError(f"Blockchain is not valid! Error on block {chain_valid}. Altered Chain!")

def throwError(msg):
    """
        Method to throw an error from Blockshell.
    """
    print(f"{ Fore.RED }{ msg }{ Fore.RESET }")

def printSuccess(msg):
    """
        Method to print success message from Blockshell.
    """
    print(f"{ Fore.GREEN }{ msg }{ Fore.RESET }")