"""
This file is part of pilang.

pilang is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

pilang is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with pilang.  If not, see <https://www.gnu.org/licenses/>.
"""
import sys
import errors
import rtypes


class builtin:
    def __init__(self, environ):
        self.commands = {
            "ret": self.cmd_ret,
            "get": self.cmd_get,
            "len": self.cmd_len,
            "catch": self.cmd_catch,
            "exit": self.cmd_exit,
            "marker": self.cmd_marker,
            "printnnl": self.cmd_printnnl,
            "print": self.cmd_print,
            "input": self.cmd_input,
            "set": self.cmd_set,
            "inc": self.cmd_inc,
            "dec": self.cmd_dec,
            "del": self.cmd_del,
            "eval": self.cmd_eval,
            "cmp": self.cmd_cmp,
            "lower": self.cmd_lower
            }
        self.environ = environ
    
    def processor(self, command, args):
        try:
            return self.commands[command](args)
        except KeyError:
            return errors.nochsuchcmd
    
    def cmd_ret(self, args):
        return " ".join(args)
    
    def cmd_get(self, args):
        if len(args) != 2:
            return errors.badarguments
        try:
            return args[0][int(round(float(args[1])))]
        except:
            return errors.badarguments
    
    def cmd_len(self, args):
        result = 0
        for arg in args:
            result += len(arg)
        return str(result)
    
    def cmd_catch(self, args):
        if args == []:
            self.environ.catch = not self.environ.catch
        else:
            if args[0].lower() == "true":
                self.environ.catch = True
            elif args[0].lower() == "false":
                self.environ.catch = False
            else:
                return errors.badarguments
    
    def cmd_exit(self, args):
        try:
            sys.exit(int(args[0]))
        except ValueError:
            return errors.badarguments
        except IndexError:
            return errors.badarguments
    
    def cmd_marker(self, args):
        if len(args) != 2:
            return errors.badarguments
        if args[0] == "set":
            raise rtypes.goto(marker=str(args[1]), define=True)
        elif args[0] == "goto":
            raise rtypes.goto(marker=str(args[1]), define=False)
        else:
            return errors.badarguments
    
    def cmd_printnnl(self, args):
        return self.cmd_print(args, nonline=True)
    
    def cmd_print(self, args, nonline=False):
        for arg in args:
            print(arg, end="", flush=nonline)
        if not nonline:
            print()
        return rtypes.success
    
    def cmd_input(self, args):
        self.cmd_print(args, nonline=True)
        try:
            return input()
        except EOFError:
            print()
            return errors.inputeof
    
    def cmd_set(self, args):
        if len(args) != 2:
            return errors.badarguments
        self.environ.variables[args[0]] = args[1]
        return rtypes.success
    
    def cmd_inc(self, args):
        if len(args) == 1:
            args.append(1)
        if not len(args) == 2:
            return errors.badarguments
        try:
            self.environ.variables[args[0]] = str(float(self.environ.variables[args[0]]) + float(args[1]))
        except KeyError:
            return errors.badarguments
        return rtypes.success
    
    def cmd_dec(self, args):
        if len(args) < 2:
            args.append(1)
        return self.cmd_inc(args[0], -args[1])
    
    def cmd_del(self, args):
        # Check if variable exists
        for arg in args:
            if not arg in self.environ.variables.keys():
                return errors.nosuchvariable
        # Actually do that stuff
        for arg in args:
            del self.environ.variables[arg]
        return rtypes.success
    
    def cmd_lower(self, args):
        return str(args[0].lower())
    
    def cmd_cmp(self, args):
        # Check
        try:
            action, var1, var2, *commands = args
            if action == "equal":
                matches = str(var1) == str(var2)
            elif action == "nonequal":
                matches = str(var1) != str(var2)
            elif action == "bigger":
                matches = float(var1) > float(var2)
            elif action == "smaller":
                matches = float(var1) < float(var2)
            elif action in ["isnum", "isnotnum"]:
                try:
                    float(var1)
                    float(var2)
                    matches = True
                except ValueError:
                    matches = False
                if action == "isnotnum":
                    matches = not matches
            else:
                return errors.badarguments
            if commands == []:
                return matches
        except ValueError:
            return errors.badarguments
        # Evaluate list of commands if comparisation matches
        if matches:
            return self.cmd_eval(commands)
        else:
            return rtypes.fail
    
    def cmd_eval(self, args):
        for command in args:
            lastres = self.environ.evaluate(command)
        return lastres


def adder(registerer):
    registerer(builtin)