import re
from src import EventManager, ModuleManager, utils
from . import outs

COMMAND_METHOD = "command-method"
COMMAND_METHODS = ["PRIVMSG", "NOTICE"]

REGEX_ARG_NUMBER = re.compile(r"\$(\d+)(-?)")

MSGID_TAG = utils.irc.MessageTag("msgid", "draft/msgid")

def _command_method_validate(s):
    if s.upper() in COMMAND_METHODS:
        return s.upper()

@utils.export("channelset", {"setting": "command-prefix",
    "help": "Set the command prefix used in this channel"})
@utils.export("serverset", {"setting": "command-prefix",
    "help": "Set the command prefix used on this server"})
@utils.export("serverset", {"setting": "command-method",
    "help": "Set the method used to respond to commands",
    "validate": _command_method_validate})
@utils.export("channelset", {"setting": "command-method",
    "help": "Set the method used to respond to commands",
    "validate": _command_method_validate})
@utils.export("channelset", {"setting": "hide-prefix",
    "help": "Disable/enable hiding prefix in command reponses",
    "validate": utils.bool_or_none})
@utils.export("channelset", {"setting": "commands",
    "help": "Disable/enable responding to commands in-channel",
    "validate": utils.bool_or_none})
@utils.export("channelset", {"setting": "prefixed-commands",
    "help": "Disable/enable responding to prefixed commands in-channel",
    "validate": utils.bool_or_none})
class Module(ModuleManager.BaseModule):
    def on_load(self):
        self.exports.add("is-ignored", self._is_ignored)

    @utils.hook("new.user|channel")
    def new(self, event):
        if "user" in event:
            target = event["user"]
        else:
            target = event["channel"]
        target.last_stdout = None
        target.last_stderr = None

    def has_command(self, command):
        return command.lower() in self.events.on("received").on(
            "command").get_children()
    def get_hooks(self, command):
        return self.events.on("received.command").on(command
            ).get_hooks()

    def is_highlight(self, server, s):
        if s and s[-1] in [":", ","]:
            s = s[:-1]
        return server.is_own_nickname(s)

    def _get_aliases(self, server):
        return server.get_setting("command-aliases", {})
    def _set_aliases(self, server, aliases):
        server.set_setting("command-aliases", aliases)

    def _alias_arg_replace(self, s, args_split):
        for match in REGEX_ARG_NUMBER.finditer(s):
            index = int(match.group(1))
            continuous = match.group(2) == "-"

            if index >= len(args_split):
                raise IndexError("Unknown alias arg index")

            if continuous:
                replace = " ".join(args_split[index:])
            else:
                replace = args_split[index]
            s = s.replace(match.group(0), replace)
        return s.split(" ")

    def _command_method(self, target, server):
        return target.get_setting(COMMAND_METHOD,
            server.get_setting(COMMAND_METHOD, "PRIVMSG")).upper()

    def _is_ignored(self, server, user, command):
        if user.get_setting("ignore", False):
            return True
        elif user.get_setting("ignore-%s" % command, False):
            return True
        elif server.get_setting("ignore-%s" % command, False):
            return True
        return False

    def message(self, event, command, args_index=1):
        args_split = event["message_split"][args_index:]
        if not self.has_command(command):
            aliases = self._get_aliases(event["server"])
            if command.lower() in aliases:
                command, _, new_args = aliases[command.lower()].partition(" ")

                try:
                    args_split = self._alias_arg_replace(new_args, args_split)
                except IndexError:
                    return

        if self.has_command(command):
            if self._is_ignored(event["server"], event["user"], command):
                return

            hook = None
            target = None
            for potential_hook in self.get_hooks(command):
                alias_of = self._get_alias_of(potential_hook)
                if alias_of:
                    if self.has_command(alias_of):
                        potential_hook = self.get_hooks(alias_of)[0]
                    else:
                        raise ValueError(
                            "'%s' is an alias of unknown command '%s'"
                           % (command.lower(), alias_of.lower()))

                is_channel = "channel" in event
                if not is_channel and potential_hook.kwargs.get("channel_only"):
                    continue
                if is_channel and potential_hook.kwargs.get("private_only"):
                    continue

                hook = potential_hook
                target = event["user"] if not is_channel else event["channel"]
                break

            if not hook:
                return

            module_name = self._get_prefix(hook) or ""
            if not module_name and hasattr(hook.function, "__self__"):
                module_name = hook.function.__self__._name

            msgid = MSGID_TAG.get_value(event["tags"])
            statusmsg = "".join(event.get("statusmsg", []))
            stdout = outs.StdOut(event["server"], module_name, target, msgid,
                statusmsg)
            stderr = outs.StdErr(event["server"], module_name, target, msgid,
                statusmsg)
            command_method = self._command_method(target, event["server"])

            if hook.kwargs.get("remove_empty", True):
                args_split = list(filter(None, args_split))

            min_args = hook.kwargs.get("min_args")
            if min_args and len(args_split) < min_args:
                command_prefix = ""
                if is_channel:
                    command_prefix = self._command_prefix(event["server"],
                        target)
                usage = self._get_usage(hook, command, command_prefix)
                if usage:
                    stderr.write("Not enough arguments, usage: %s" %
                        usage).send(command_method)
                else:
                    stderr.write("Not enough arguments (minimum: %d)" %
                        min_args).send(command_method)
            else:
                returns = self.events.on("preprocess.command").call_unsafe(
                    hook=hook, user=event["user"], server=event["server"],
                    target=target, is_channel=is_channel, tags=event["tags"],
                    args_split=args_split)

                hard_fail = False
                force_success = False
                error = None
                for returned in returns:
                    if returned == utils.consts.PERMISSION_HARD_FAIL:
                        hard_fail = True
                        break
                    elif returned == utils.consts.PERMISSION_FORCE_SUCCESS:
                        force_success = True
                    elif returned:
                        error = returned

                if hard_fail or (not force_success and error):
                    if error:
                        stderr.write(error).send(command_method)
                        target.buffer.skip_next()
                    return

                args = " ".join(args_split)
                server = event["server"]
                user = event["user"]

                new_event = self.events.on("received.command").on(command
                    ).make_event(user=user, server=server, target=target,
                    args=args, tags=event["tags"], args_split=args_split,
                    stdout=stdout, stderr=stderr, command=command.lower(),
                    is_channel=is_channel)

                self.log.trace("calling command '%s': %s",
                    [command, new_event.kwargs])
                try:
                    hook.call(new_event)
                except utils.EventError as e:
                    stderr.write(str(e))

                if not hook.kwargs.get("skip_out", False):
                    command_method = self._command_method(
                        target, event["server"])
                    stdout.send(command_method)
                    stderr.send(command_method)
                    target.last_stdout = stdout
                    target.last_stderr = stderr
            target.buffer.skip_next()
        event.eat()

    def _command_prefix(self, server, channel):
        return channel.get_setting("command-prefix",
            server.get_setting("command-prefix", "!"))

    @utils.hook("received.message.channel", priority=EventManager.PRIORITY_LOW)
    def channel_message(self, event):
        if event["action"]:
            return

        commands_enabled = event["channel"].get_setting("commands", True)
        if not commands_enabled:
            return
        prefixed_commands = event["channel"].get_setting("prefixed-commands", True)

        command_prefix = self._command_prefix(event["server"], event["channel"])
        if event["message_split"][0].startswith(command_prefix):
            if not prefixed_commands:
                return
            command = event["message_split"][0].replace(
                command_prefix, "", 1).lower()
            self.message(event, command)
        elif len(event["message_split"]) > 1 and self.is_highlight(
                event["server"], event["message_split"][0]):
            command = event["message_split"][1].lower()
            self.message(event, command, 2)

    @utils.hook("received.message.private", priority=EventManager.PRIORITY_LOW)
    def private_message(self, event):
        if event["message_split"] and not event["action"]:
            command = event["message_split"][0].lower()
            self.message(event, command)

    def _get_help(self, hook):
        return hook.get_kwarg("help", None) or hook.docstring.description
    def _get_usage(self, hook, command, command_prefix=""):
        command = "%s%s" % (command_prefix, command)
        usage = hook.get_kwarg("usage", None)
        if usage:
            usages = [usage]
        else:
            usages = hook.docstring.var_items.get("usage", None)

        if usages:
            return " | ".join(
                "%s %s" % (command, usage) for usage in usages)
        return usage

    def _all_command_hooks(self):
        all_hooks = {}
        for child_name in self.events.on("received.command").get_children():
            hooks = self.events.on("received.command").on(child_name
                ).get_hooks()
            if hooks:
                all_hooks[child_name.lower()] = hooks[0]
        return all_hooks

    def _get_prefix(self, hook):
        return hook.get_kwarg("prefix", None)
    def _get_alias_of(self, hook):
        return hook.get_kwarg("alias_of", None)

    @utils.hook("received.command.help")
    def help(self, event):
        """
        :help: Show help for a given command
        :usage: [module [command]]
        """
        if event["args"]:
            module_name = event["args_split"][0]
            module = self.bot.modules.from_name(module_name)
            if module == None:
                raise utils.EventError("No such module '%s'" % module_name)

            if len(event["args_split"]) == 1:
                commands = []
                for command, command_hook in self._all_command_hooks().items():
                    if (command_hook.context == module.context and
                            not self._get_alias_of(command_hook)):
                        commands.append(command)

                event["stdout"].write("Commands for %s module: %s" % (
                    module.name, ", ".join(commands)))
            else:
                requested_command = event["args_split"][1].lower()
                available_commands = self._all_command_hooks()
                if requested_command in available_commands:
                    command_hook = available_commands[requested_command]
                    help = self._get_help(command_hook)

                    if help:
                        event["stdout"].write("%s: %s" % (
                            requested_command, help))
                    else:
                        event["stderr"].write("No help available for %s" %
                            requested_command)

                else:
                    event["stderr"].write("Unknown command '%s'" %
                        requested_command)
        else:
            contexts = {}
            for command, command_hook in self._all_command_hooks().items():
                if not command_hook.context in contexts:
                    module = self.bot.modules.from_context(command_hook.context)
                    contexts[module.context] = module.name

            modules_available = sorted(contexts.values())
            event["stdout"].write("Modules: %s" % ", ".join(modules_available))

    @utils.hook("received.command.usage", min_args=1)
    def usage(self, event):
        """
        :help: Show the usage for a given command
        :usage: <command>
        """
        command_prefix = ""
        if event["is_channel"]:
            command_prefix = self._command_prefix(event["server"],
                event["target"])

        command = event["args_split"][0].lower()
        if command in self.events.on("received").on(
                "command").get_children():
            hooks = self.events.on("received.command").on(command).get_hooks()
            usage = self._get_usage(hooks[0], command, command_prefix)

            if usage:
                event["stdout"].write("Usage: %s" % usage)
            else:
                event["stderr"].write("No usage help available for %s" % command)
        else:
            event["stderr"].write("Unknown command '%s'" % command)

    @utils.hook("received.command.more", skip_out=True)
    def more(self, event):
        """
        :help: Show more output from the last command
        """
        if event["target"].last_stdout and event["target"].last_stdout.has_text():
            event["target"].last_stdout.send(
                self._command_method(event["target"], event["server"]))

    @utils.hook("received.command.ignore", min_args=1)
    def ignore(self, event):
        """
        :help: Ignore commands from a given user
        :usage: <nickname> [command]
        :permission: ignore
        """
        setting = "ignore"
        for_str = ""
        if len(event["args_split"]) > 1:
            command = event["args_split"][1].lower()
            setting = "ignore-%s" % command
            for_str = " for '%s'" % command

        user = event["server"].get_user(event["args_split"][0])
        if user.get_setting(setting, False):
            event["stderr"].write("I'm already ignoring '%s'%s" %
                (user.nickname, for_str))
        else:
            user.set_setting(setting, True)
            event["stdout"].write("Now ignoring '%s'%s" %
                (user.nickname, for_str))

    @utils.hook("received.command.unignore", min_args=1)
    def unignore(self, event):
        """
        :help: Unignore commands from a given user
        :usage: <nickname> [command]
        :permission: unignore
        """
        setting = "ignore"
        for_str = ""
        if len(event["args_split"]) > 1:
            command = event["args_split"][1].lower()
            setting = "ignore-%s" % command
            for_str = " for '%s'" % command

        user = event["server"].get_user(event["args_split"][0])
        if not user.get_setting(setting, False):
            event["stderr"].write("I'm not ignoring '%s'%s" %
                (user.nickname, for_str))
        else:
            user.del_setting(setting)
            event["stdout"].write("Removed ignore for '%s'%s" %
                (user.nickname, for_str))

    @utils.hook("received.command.serverignore", in_args=1)
    def server_ignore(self, event):
        """
        :permission: server-ignore
        """
        command = event["args_split"][0].lower()
        setting = "ignore-%s" % command

        if event["server"].get_setting(setting, False):
            event["stderr"].write("I'm already ignoring '%s' for %s" %
                (command, str(event["server"])))
        else:
            event["server"].set_setting(setting, True)
            event["stdout"].write("Now ignoring '%s' for %s" %
                (command, str(event["server"])))

    @utils.hook("received.command.serverunignore", in_args=1)
    def server_unignore(self, event):
        """
        :permission: server-unignore
        """
        command = event["args_split"][0].lower()
        setting = "ignore-%s" % command

        if not event["server"].get_setting(setting, False):
            event["stderr"].write("I'm not ignoring '%s' for %s" %
                (command, str(event["server"])))
        else:
            event["server"].del_setting(setting)
            event["stdout"].write("No longer ignoring '%s' for %s" %
                (command, str(event["server"])))

    @utils.hook("send.stdout")
    def send_stdout(self, event):
        stdout = outs.StdOut(event["server"], event["module_name"],
            event["target"], event.get("msgid", None),
            event.get("statusmsg", ""))

        if event.get("hide_prefix", False):
            stdout.hide_prefix()

        stdout.write(event["message"]).send(
            self._command_method(event["target"], event["server"]))
        if stdout.has_text():
            event["target"].last_stdout = stdout
    @utils.hook("send.stderr")
    def send_stderr(self, event):
        stderr = outs.StdErr(event["server"], event["module_name"],
            event["target"], event.get("msgid", None),
            event.get("statusmsg", ""))

        if event.get("hide_prefix", False):
            stderr.hide_prefix()

        stderr.write(event["message"]).send(
            self._command_method(event["target"], event["server"]))
        if stderr.has_text():
            event["target"].last_stderr = stderr

    @utils.hook("received.command.alias", min_args=2)
    def add_alias(self, event):
        """
        :help: Add a command alias
        :usage: <alias> <command> <args...>
        :permission: command-alias
        """
        alias = event["args_split"][0].lower()
        command = " ".join(event["args_split"][1:])
        aliases = self._get_aliases(event["server"])
        aliases[alias] = command
        self._set_aliases(event["server"], aliases)
        event["stdout"].write("Added '%s' alias" % alias)

    @utils.hook("received.command.removealias", min_args=1)
    def remove_alias(self, event):
        """
        :help: Remove a command alias
        :usage: <alias>
        :permission: command-alias
        """
        alias = event["args_split"][0].lower()
        aliases = self._get_aliases(event["server"])

        if not alias in aliases:
            raise utils.EventError("No '%s' alias" % alias)

        del aliases[alias]
        self._set_aliases(event["server"], aliases)
        event["stdout"].write("Removed '%s' alias" % alias)