# Copyright 2014 BitPay Inc.
# Copyright 2016 The Bitcoin Core developers
# Distributed under the MIT software license, see the accompanying
# file COPYING or http://www.opensource.org/licenses/mit-license.php.
from __future__ import division,print_function,unicode_literals
import subprocess
import os
import json
import sys
import binascii
import difflib
import logging

def parse_output(a, fmt):
    """Parse the output according to specified format.

    Raise an error if the output can't be parsed."""
    if fmt == 'json': # json: compare parsed data
        return json.loads(a)
    elif fmt == 'hex': # hex: parse and compare binary data
        return binascii.a2b_hex(a.strip())
    else:
        raise NotImplementedError("Don't know how to compare %s" % fmt)

def bctest(testDir, testObj, exeext):
    """Runs a single test, comparing output and RC to expected output and RC.

    Raises an error if input can't be read, executable fails, or output/RC
    are not as expected. Error is caught by bctester() and reported.
    """
    # Get the exec names and arguments
    execprog = testObj['exec'] + exeext
    execargs = testObj['args']
    execrun = [execprog] + execargs

    # Read the input data (if there is any)
    stdinCfg = None
    inputData = None
    if "input" in testObj:
        filename = testDir + "/" + testObj['input']
        inputData = open(filename).read()
        stdinCfg = subprocess.PIPE

    # Read the expected output data (if there is any)
    outputFn = None
    outputData = None
    if "output_cmp" in testObj:
        outputFn = testObj['output_cmp']
        outputType = os.path.splitext(outputFn)[1][1:] # output type from file extension (determines how to compare)
        try:
            outputData = open(testDir + "/" + outputFn).read()
        except:
            logging.error("Output file " + outputFn + " can not be opened")
            raise
        if not outputData:
            logging.error("Output data missing for " + outputFn)
            raise Exception

    # Run the test
    proc = subprocess.Popen(execrun, stdin=stdinCfg, stdout=subprocess.PIPE, stderr=subprocess.PIPE,universal_newlines=True)
    try:
        outs = proc.communicate(input=inputData)
    except OSError:
        logging.error("OSError, Failed to execute " + execprog)
        raise

    if outputData:
        # Parse command output and expected output
        try:
            a_parsed = parse_output(outs[0], outputType)
        except Exception as e:
            logging.error('Error parsing command output as %s: %s' % (outputType,e))
            raise
        try:
            b_parsed = parse_output(outputData, outputType)
        except Exception as e:
            logging.error('Error parsing expected output %s as %s: %s' % (outputFn,outputType,e))
            raise
        # Compare data
        if a_parsed != b_parsed:
            logging.error("Output data mismatch for " + outputFn + " (format " + outputType + ")")
            raise Exception
        # Compare formatting
        if outs[0] != outputData:
            error_message = "Output formatting mismatch for " + outputFn + ":\n"
            error_message += "".join(difflib.context_diff(outputData.splitlines(True),
                                                          outs[0].splitlines(True),
                                                          fromfile=outputFn,
                                                          tofile="returned"))
            logging.error(error_message)
            raise Exception

    # Compare the return code to the expected return code
    wantRC = 0
    if "return_code" in testObj:
        wantRC = testObj['return_code']
    if proc.returncode != wantRC:
        logging.error("Return code mismatch for " + outputFn)
        raise Exception


    if "error_txt" in testObj:
        want_error = testObj["error_txt"]
        # Compare error text
        # TODO: ideally, we'd compare the strings exactly and also assert
        # That stderr is empty if no errors are expected. However, bitcoin-tx
        # emits DISPLAY errors when running as a windows application on
        # linux through wine. Just assert that the expected error text appears
        # somewhere in stderr.
        if want_error not in outs[1]:
            logging.error("Error mismatch:\n" + "Expected: " + want_error + "\nReceived: " + outs[1].rstrip())
            raise Exception


def bctester(testDir, input_basename, buildenv):
    """ Loads and parses the input file, runs all tests and reports results"""
    input_filename = testDir + "/" + input_basename
    raw_data = open(input_filename).read()
    input_data = json.loads(raw_data)

    failed_testcases = []

    for testObj in input_data:
        try:
            bctest(testDir, testObj, buildenv.exeext)
            logging.info("PASSED: " + testObj["description"])
        except:
            logging.info("FAILED: " + testObj["description"])
            failed_testcases.append(testObj["description"])

    if failed_testcases:
        logging.error("FAILED TESTCASES: [" + ", ".join(failed_testcases) + "]")
        sys.exit(1)
    else:
        sys.exit(0)
