import urllib
import urllib2
import json
import random
from urllib2 import URLError
import sys
import time
import threading

COMPILER_PATH = "interface/HUTN"

MODE_UNCONNECTED = 0
MODE_UNAUTHORIZED = 1
MODE_MODELLING = 2
MODE_SERVICE = 6

# Bind to the compiler (might have to update path manually!)
sys.path.append(COMPILER_PATH)
from hutn_compiler.compiler import main as do_compile

# Exceptions
class ModelverseException(Exception):
    pass

class UnknownError(ModelverseException):
    pass

class UnknownIdentifier(ModelverseException):
    pass

class CompilationError(ModelverseException):
    pass

class NoSuchAttribute(ModelverseException):
    pass

class UnknownModel(ModelverseException):
    pass

class ConnectionError(ModelverseException):
    pass

class ModelExists(ModelverseException):
    pass

class PermissionDenied(ModelverseException):
    pass

class InvalidMode(ModelverseException):
    pass

class InterfaceMismatch(ModelverseException):
    pass

class UnknownMetamodellingHierarchy(ModelverseException):
    pass

# Helper functions and configuration: do not use yourself!
taskname = None
address = None
last_output = None
mode = MODE_UNCONNECTED
prev_mode = None
current_model = None
registered_metamodels = {}

def _check_type(value):
    if not isinstance(value, (int, long, float, str, unicode, bool)):
        raise UnsupportedValue("%s : %s" % (value, str(type(value))))

def _check_type_list(value):
    if isinstance(value, list):
        [_check_type(i) for i in value]
    else:
        _check_type(value)

def _goto_mode(new_mode, model_name=None):
    global mode

    if mode == new_mode:
        return
    else:
        # Go to a mode that we have no automatic transfer to: raise exception
        raise InvalidMode("Required mode: %s, current mode: %s" % (new_mode, mode))

def _input(value, port=None):
    # Ugly json encoding of primitives
    if port is None:
        port = taskname
    if isinstance(value, type([])):
        value = json.dumps(value)
        urllib2.urlopen(urllib2.Request(address, urllib.urlencode({"op": "set_input", "data": value, "taskname": port}))).read()
    else:
        value = json.dumps(value)
        #print("Set input: " + str(value))
        urllib2.urlopen(urllib2.Request(address, urllib.urlencode({"op": "set_input", "value": value, "taskname": port}))).read()

def _input_raw(value, taskname):
    # Ugly json encoding of primitives
    urllib2.urlopen(urllib2.Request(address, urllib.urlencode({"op": "set_input", "value": value, "taskname": taskname}))).read()

def _compile_AL(code):
    # Compile an action language file and send the compiled code
    code_fragments = code.split("\n")
    code_fragments = [i for i in code_fragments if i.strip() != ""]
    code_fragments = [i.replace("    ", "\t") for i in code_fragments]
    initial_tabs = min([len(i) - len(i.lstrip("\t")) for i in code_fragments])
    code_fragments = [i[initial_tabs:] for i in code_fragments]
    code_fragments.append("")
    code = "\n".join(code_fragments)

    with open(".code.alc", "w") as f:
        f.write(code)
        f.flush()

    compiled = do_compile(".code.alc", COMPILER_PATH + "/grammars/actionlanguage.g", "CS")
    return compiled

def _compile_model(code):
    # Compile a model and send the compiled graph
    # First change multiple spaces to a tab
    code_fragments = code.split("\n")
    code_fragments = [i for i in code_fragments if i.strip() != ""]
    code_fragments = [i.replace("    ", "\t") for i in code_fragments]
    initial_tabs = min([len(i) - len(i.lstrip("\t")) for i in code_fragments])
    code_fragments = [i[initial_tabs:] for i in code_fragments]
    code_fragments.append("")
    code = "\n".join(code_fragments)

    with open(".model.mvc", "w") as f:
        f.write(code)
        f.flush()

    return do_compile(".model.mvc", COMPILER_PATH + "/grammars/modelling.g", "M")

def _output(expected=None,port=None):
    if port is None:
        port = taskname
    try:
        global last_output
        last_output = json.loads(urllib2.urlopen(urllib2.Request(address, urllib.urlencode({"op": "get_output", "taskname": port}))).read())
        #print("[OUT] %s" % last_output)
    except:
        raise UnknownError()
    if expected is not None and last_output != expected:
        raise InterfaceMismatch(_last_output(), expected)
    return last_output

def _last_output():
    return last_output

# Raise common exceptions
def _handle_output(requested=None, split=None):
    value = _output()
    if value.startswith("Model exists: "):
        raise ModelExists(value.split(": ", 1)[1])
    elif value.startswith("Permission denied"):
        raise PermissionDenied(value.split(": ", 1)[1])
    elif value.startswith("Model not found: "):
        raise UnknownModel(value.split(": ", 1)[1])
    elif value.startswith("Element not found: "):
        raise UnknownIdentifier(value.split(": ", 1)[1])
    elif value.startswith("Element exists: "):
        raise ElementExists(value.split(": ", 1)[1])
    elif value.startswith("Attribute not found: "):
        raise NoSuchAttribute(value.split(": ", 1)[1])
    elif requested is not None and value.startswith(requested):
        if split is None:
            return value
        else:
            splitted = value.strip().split(split, 1)
            if len(splitted) == 1:
                return ""
            else:
                return splitted[1].rstrip()
    else:
        raise InterfaceMismatch(value)
    
def _model_modify(model_name, metamodel_name):
    """Modify an existing model."""
    global mode
    global prev_mode

    if mode == MODE_MANUAL:
        prev_mode = MODE_MANUAL
        mode = MODE_MODIFY
        return None

    _goto_mode(MODE_MODELLING)
    prev_mode = MODE_MODELLING

    _input(["model_modify", model_name, metamodel_name])
    _handle_output("Success")
    global current_model
    current_model = model_name
    # Mode has changed
    mode = MODE_MODIFY
    _output("Model loaded, ready for commands!")

def _model_exit():
    """Leave model modify mode."""
    global mode
    global prev_mode

    if prev_mode == MODE_MANUAL:
        mode = MODE_MANUAL
        return

    if mode != MODE_MODIFY:
        raise InvalidMode()

    _input("exit")
    _output("Success")
    mode = MODE_MODELLING

def alter_context(model_name, metamodel_name):
    global registered_metamodels
    registered_metamodels[model_name] = metamodel_name

# Main MvC operations
def init(address_param="127.0.0.1:8001", timeout=20.0):
    """Starts up the connection to the Modelverse."""
    global mode
    global address
    global taskname
    address = "http://%s" % address_param
    start_time = time.time()
    taskname = random.random()
    while 1:
        try:
            _input_raw('"%s"' % taskname, "task_manager")
            mode = MODE_UNAUTHORIZED
            break
        except URLError as e:
            if time.time() - start_time > timeout:
                raise ConnectionError(e.reason)
            else:
                time.sleep(0.1)

def login(username, password):
    """Log in a user, if user doesn't exist, it is created."""
    global mode
    _goto_mode(MODE_UNAUTHORIZED)

    _output("Log on as which user?")
    _input(username)
    if _output() == "Password for existing user?":
        _input(password)
        if _output() == "Welcome to the Model Management Interface v2.0!":
            _output("Use the 'help' command for a list of possible commands")
            _input("quiet")
            mode = MODE_MODELLING
        elif _last_output() == "Wrong password!":
            raise PermissionDenied()
        else:
            raise InterfaceMismatch(_last_output())
    elif _last_output() == "This is a new user: please give password!":
        _input(password)
        _output("Please repeat the password")
        _input(password)
        if _output() == "Passwords match!":
            _output("Welcome to the Model Management Interface v2.0!")
            _output("Use the 'help' command for a list of possible commands")
            _input("quiet")
            mode = MODE_MODELLING
        elif _last_output() == "Not the same password!":
            # We just sent the same password, so it should be identical, unless the interface changed
            raise InterfaceMismatch(_last_output())
        else:
            raise InterfaceMismatch(_last_output())
    else:
        raise InterfaceMismatch(_last_output())

def service_register(name, function):
    """Register a function as a service with a specific name."""

    def service_process(port):
        while 1:
            thrd = threading.Thread(target=function, args=[service_get(port)])
            thrd.daemon = True
            thrd.start()

    global mode
    _goto_mode(MODE_MODELLING)

    _input(["service_register", name])

    # Now we are in service-mode
    mode = MODE_SERVICE
    port = _handle_output("Success: ", split=" ")

    # Process events in the background!
    threading.Thread(target=service_process, args=[port]).start()

def service_stop():
    """Stop the currently executing process."""
    _goto_mode(MODE_SERVICE)
    _input("service_stop")
    _handle_output("Success")

    global mode
    mode = MODE_MODELLING

def service_get(port):
    """Get the values on the specified port."""
    _goto_mode(MODE_SERVICE)

    return _output(port=port)

def service_set(port, value):
    """Set a value on a specified port."""
    _check_type_list(value)
    _goto_mode(MODE_SERVICE)

    _input(value, port=port)

def service_poll(port):
    """Checks whether or not the Modelverse side has any input ready to be processed."""
    raise NotImplementedError()