"""
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, os
from types import ModuleType
import errors
import rtypes
from rstrings import rstrings


class environment_class:
    def __init__(self):
        self.variables = {}
        self.catch = False
environment = environment_class()

class main_class:
    def __init__(self):
        self.modules = {}
        self.commands = {}
        self.environment = environment
        environment.evaluate = self.run_command
        # Load and import modules
        for module in os.listdir("modules"):
            if module[-3:] == ".py" or module[-4:] == ".pyc":
                self.import_module(f"modules/{module}")
    
    def is_error(self, robj):
        try:
            return robj.__name__ in errors.__dict__.keys()
        except AttributeError:
            return False
    
    def get_rstring(self, robj, errorsonly=True):
        iserr = False
        try:
            if not "errorsonly" in self.__dict__.keys():
                self.errorsonly = errorsonly
            if isinstance(robj,type):
                if self.is_error(robj):
                    iserr = True
                if self.errorsonly and not self.is_error(robj):
                    return None
                try:
                    return rstrings[robj.__name__]
                except KeyError:
                    return "py." + robj.__name__
            else:
                return robj
        finally:
            if environment.catch and iserr:
                environment.catch = False
                raise RuntimeError(self.get_rstring(robj))
    
    def import_module(self, path):
        with open(path) as file:
            modcode = file.read()
        mod = ModuleType(path)
        exec(modcode, mod.__dict__)
        return mod.adder(self.add_module)
    
    def add_module(self, module_class):
        modulename = module_class.__name__
        self.modules[modulename] = module_class(environment)
        for command in self.modules[modulename].commands:
            self.commands[command] = self.modules[modulename]
    
    def run_command(self, commandstr):
        try: commandstr, _ = commandstr.split("#", 1) # Split off comments
        except ValueError: pass
        commandstr = commandstr.lstrip()
        if commandstr == "":             # Empty command (does nothing)
            return
        elif commandstr.startswith("~"): # Variable
            try:
                return environment.variables[commandstr[1:]]
            except KeyError:
                return errors.nosuchvariable
        else:                          # Actual command
            try: command, argsstr = commandstr.split(" ", 1)
            except ValueError: command, argsstr = (commandstr, "")
            try: commandsplit = command.split(".", 1)
            except ValueError: commandsplit = [command]
            # Get module to parse command
            if len(commandsplit) == 1: # Non-exact command
                try:
                    module = self.commands[command]
                except KeyError:
                    return errors.nochsuchcmd
            else:                      # Exact command
                try:
                    module = self.modules[commandsplit[0]]
                except KeyError:
                    return errors.nosuchmodule
                command = commandsplit[1]
                if not command in self.commands.keys():
                    return errors.nochsuchcmd
            # Split arguments if required
            argsstr += ","
            args = []
            if argsstr != ",":
                currarg = ""
                instring = False
                arginstring = False
                charig = False
                skipall = False
                for char in argsstr:
                    if skipall:
                        continue
                    elif char == '"' and not charig:
                        instring = not instring
                        if currarg == "":
                            arginstring = True
                    elif char == "#" and  not charig and not instring:
                        skipall = True
                    elif char == ',' and not charig and not instring:
                        if len(currarg) != 0 and currarg[0] == "$" and not arginstring:
                            currarg = self.get_rstring(self.run_command(currarg[1:]))
                        args.append(currarg)
                        currarg = ""
                        arginstring = False
                    elif char == "\\" and not charig:
                        charig = True
                    else:
                        currarg += char
                        charig = False
            else:
                pass
            # Run command
            #print([command] + [args])
            return module.processor(command, args)