#!/usr/bin/env python

from __future__ import print_function

from collections import defaultdict
from os import listdir
from os.path import abspath, basename, dirname, isdir, isfile, join, realpath, relpath, splitext
import re
from subprocess import Popen, PIPE
import sys
from threading import Timer

# Runs the tests.
WREN_DIR = dirname(dirname(realpath(__file__)))
WREN_APP = join(WREN_DIR, 'bin', 'wrend')
TEST_APP = join(WREN_DIR, 'build', 'debug', 'test', 'wrend')

EXPECT_PATTERN = re.compile(r'// expect: ?(.*)')
EXPECT_ERROR_PATTERN = re.compile(r'// expect error(?! line)')
EXPECT_ERROR_LINE_PATTERN = re.compile(r'// expect error line (\d+)')
EXPECT_RUNTIME_ERROR_PATTERN = re.compile(r'// expect runtime error: (.+)')
ERROR_PATTERN = re.compile(r'\[.* line (\d+)\] Error')
STACK_TRACE_PATTERN = re.compile(r'\[main line (\d+)\] in')
STDIN_PATTERN = re.compile(r'// stdin: (.*)')
SKIP_PATTERN = re.compile(r'// skip: (.*)')
NONTEST_PATTERN = re.compile(r'// nontest')

passed = 0
failed = 0
num_skipped = 0
skipped = defaultdict(int)
expectations = 0


class Test:
  def __init__(self, path):
    self.path = path
    self.output = []
    self.compile_errors = set()
    self.runtime_error_line = 0
    self.runtime_error_message = None
    self.exit_code = 0
    self.input_bytes = None
    self.failures = []


  def parse(self):
    global num_skipped
    global skipped
    global expectations

    input_lines = []
    line_num = 1
    with open(self.path, 'r') as file:
      for line in file:
        match = EXPECT_PATTERN.search(line)
        if match:
          self.output.append((match.group(1), line_num))
          expectations += 1

        match = EXPECT_ERROR_PATTERN.search(line)
        if match:
          self.compile_errors.add(line_num)

          # If we expect a compile error, it should exit with EX_DATAERR.
          self.exit_code = 65
          expectations += 1

        match = EXPECT_ERROR_LINE_PATTERN.search(line)
        if match:
          self.compile_errors.add(int(match.group(1)))

          # If we expect a compile error, it should exit with EX_DATAERR.
          self.exit_code = 65
          expectations += 1

        match = EXPECT_RUNTIME_ERROR_PATTERN.search(line)
        if match:
          self.runtime_error_line = line_num
          self.runtime_error_message = match.group(1)
          # If we expect a runtime error, it should exit with EX_SOFTWARE.
          self.exit_code = 70
          expectations += 1

        match = STDIN_PATTERN.search(line)
        if match:
          input_lines.append(match.group(1))

        match = SKIP_PATTERN.search(line)
        if match:
          num_skipped += 1
          skipped[match.group(1)] += 1
          return False

        match = NONTEST_PATTERN.search(line)
        if match:
          # Not a test file at all, so ignore it.
          return False

        line_num += 1


    # If any input is fed to the test in stdin, concatenate it into one string.
    if input_lines:
      self.input_bytes = "\n".join(input_lines).encode("utf-8")

    # If we got here, it's a valid test.
    return True


  def run(self, app, type):
    # Invoke wren and run the test.
    test_arg = self.path
    if type == "api test":
      # Just pass the suite name to API tests.
      test_arg = basename(splitext(test_arg)[0])

    proc = Popen([app, test_arg], stdin=PIPE, stdout=PIPE, stderr=PIPE)

    # If a test takes longer than two seconds, kill it.
    #
    # This is mainly useful for running the tests while stress testing the GC,
    # which can make a few pathological tests much slower.
    timed_out = [False]
    def kill_process(p):
      timed_out[0] = True
      p.kill()

    timer = Timer(2, kill_process, [proc])

    try:
      timer.start()
      out, err = proc.communicate(self.input_bytes)

      if timed_out[0]:
        self.fail("Timed out.")
      else:
        self.validate(type == "example", proc.returncode, out, err)
    finally:
      timer.cancel()


  def validate(self, is_example, exit_code, out, err):
    if self.compile_errors and self.runtime_error_message:
      self.fail("Test error: Cannot expect both compile and runtime errors.")
      return

    try:
      out = out.decode("utf-8").replace('\r\n', '\n')
      err = err.decode("utf-8").replace('\r\n', '\n')
    except:
      self.fail('Error decoding output.')

    error_lines = err.split('\n')

    # Validate that an expected runtime error occurred.
    if self.runtime_error_message:
      self.validate_runtime_error(error_lines)
    else:
      self.validate_compile_errors(error_lines)

    self.validate_exit_code(exit_code, error_lines)

    # Ignore output from examples.
    if is_example: return

    self.validate_output(out)


  def validate_runtime_error(self, error_lines):
    if len(error_lines) < 2:
      self.fail('Expected runtime error "{0}" and got none.',
          self.runtime_error_message)
      return

    # Make sure we got the right error.
    if error_lines[0] != self.runtime_error_message:
      self.fail('Expected runtime error "{0}" and got:',
          self.runtime_error_message)
      self.fail(error_lines[0])

    # Make sure the stack trace has the right line. Skip over any lines that
    # come from builtin libraries.
    stack_lines = error_lines[1:]
    for stack_line in stack_lines:
      match = STACK_TRACE_PATTERN.search(stack_line)
      if match: break

    if not match:
      self.fail('Expected stack trace and got:')
      for stack_line in stack_lines:
        self.fail(stack_line)
    else:
      stack_line = int(match.group(1))
      if stack_line != self.runtime_error_line:
        self.fail('Expected runtime error on line {0} but was on line {1}.',
            self.runtime_error_line, stack_line)


  def validate_compile_errors(self, error_lines):
    # Validate that every compile error was expected.
    found_errors = set()
    for line in error_lines:
      match = ERROR_PATTERN.search(line)
      if match:
        error_line = float(match.group(1))
        if error_line in self.compile_errors:
          found_errors.add(error_line)
        else:
          self.fail('Unexpected error:')
          self.fail(line)
      elif line != '':
        self.fail('Unexpected output on stderr:')
        self.fail(line)

    # Validate that every expected error occurred.
    for line in self.compile_errors - found_errors:
      self.fail('Missing expected error on line {0}.', line)


  def validate_exit_code(self, exit_code, error_lines):
    if exit_code == self.exit_code: return

    self.fail('Expected return code {0} and got {1}. Stderr:',
        self.exit_code, exit_code)
    self.failures += error_lines


  def validate_output(self, out):
    # Remove the trailing last empty line.
    out_lines = out.split('\n')
    if out_lines[-1] == '':
      del out_lines[-1]

    index = 0
    for line in out_lines:
      if sys.version_info < (3, 0):
        line = line.encode('utf-8')

      if index >= len(self.output):
        self.fail('Got output "{0}" when none was expected.', line)
      elif self.output[index][0] != line:
        self.fail('Expected output "{0}" on line {1} and got "{2}".',
            self.output[index][0], self.output[index][1], line)
      index += 1

    while index < len(self.output):
      self.fail('Missing expected output "{0}" on line {1}.',
          self.output[index][0], self.output[index][1])
      index += 1


  def fail(self, message, *args):
    if args:
      message = message.format(*args)
    self.failures.append(message)


def color_text(text, color):
  """Converts text to a string and wraps it in the ANSI escape sequence for
  color, if supported."""

  # No ANSI escapes on Windows.
  if sys.platform == 'win32':
    return str(text)

  return color + str(text) + '\033[0m'


def green(text):  return color_text(text, '\033[32m')
def pink(text):   return color_text(text, '\033[91m')
def red(text):    return color_text(text, '\033[31m')
def yellow(text): return color_text(text, '\033[33m')


def walk(dir, callback, ignored=None):
  """
  Walks [dir], and executes [callback] on each file unless it is [ignored].
  """

  if not ignored:
    ignored = []
  ignored += [".",".."]

  dir = abspath(dir)
  for file in [file for file in listdir(dir) if not file in ignored]:
    nfile = join(dir, file)
    if isdir(nfile):
      walk(nfile, callback)
    else:
      callback(nfile)


def print_line(line=None):
  # Erase the line.
  print('\033[2K', end='')
  # Move the cursor to the beginning.
  print('\r', end='')
  if line:
    print(line, end='')
    sys.stdout.flush()


def run_script(app, path, type):
  global passed
  global failed
  global num_skipped

  if (splitext(path)[1] != '.wren'):
    return

  # Check if we are just running a subset of the tests.
  if len(sys.argv) == 2:
    this_test = relpath(path, join(WREN_DIR, 'test'))
    if not this_test.startswith(sys.argv[1]):
      return

  # Update the status line.
  print_line('Passed: ' + green(passed) +
             ' Failed: ' + red(failed) +
             ' Skipped: ' + yellow(num_skipped))

  # Make a nice short path relative to the working directory.

  # Normalize it to use "/" since, among other things, wren expects its argument
  # to use that.
  path = relpath(path).replace("\\", "/")

  # Read the test and parse out the expectations.
  test = Test(path)

  if not test.parse():
    # It's a skipped or non-test file.
    return

  test.run(app, type)

  # Display the results.
  if len(test.failures) == 0:
    passed += 1
  else:
    failed += 1
    print_line(red('FAIL') + ': ' + path)
    print('')
    for failure in test.failures:
      print('      ' + pink(failure))
    print('')


def run_test(path, example=False):
  run_script(WREN_APP, path, "test")


def run_api_test(path):
  run_script(TEST_APP, path, "api test")


def run_example(path):
  # The guess number requires user input.
  if "guess_number" in path: return
  run_script(WREN_APP, path, "example")


walk(join(WREN_DIR, 'test'), run_test, ignored=['api', 'benchmark'])
walk(join(WREN_DIR, 'test', 'api'), run_api_test)
walk(join(WREN_DIR, 'example'), run_example)

print_line()
if failed == 0:
  print('All ' + green(passed) + ' tests passed (' + str(expectations) +
        ' expectations).')
else:
  print(green(passed) + ' tests passed. ' + red(failed) + ' tests failed.')

for key in sorted(skipped.keys()):
  print('Skipped ' + yellow(skipped[key]) + ' tests: ' + key)

if failed != 0:
  sys.exit(1)
