import os;
import utils

class Menu():

    def __init__(self, options: list, title: str = None, cursor: str = "> ", cursor_pos: int = 0, preview_body_function = None, preview_title_function = None, preview_args: list = None, preview_ratio: float = 0.5, circular: bool = True, skip_empty_option: bool = False, quit_button: bool = False):
        self.options = options;
        self.title = title;
        self.cursor = cursor;
        self.cursor_pos = cursor_pos;
        self.cursor_pos_x = 0;
        self.preview_body_function = preview_body_function;
        self.preview_title_function = preview_title_function;
        if (preview_args == None):
            self.preview_args = options;
        else:
            self.preview_args = preview_args;
        self.circular = circular;
        self.skip_empty_option = skip_empty_option;
        self.size = len(options)
        self.preview_ratio = preview_ratio;

    def _up(self):
        if (self.circular == False):
            if (self.cursor_pos != 0):
                self.cursor_pos = self.cursor_pos - 1
        else:
            self.cursor_pos = (self.cursor_pos - 1) % self.size;
        if (self.skip_empty_option == True):
            if (self.options[self.cursor_pos] == None
                or self.options[self.cursor_pos] == ""):
                self._up()
        self.cursor_pos_x = 0;

    def _down(self):
        if (self.circular == False):
            if (self.cursor_pos != self.size - 1):
                self.cursor_pos = self.cursor_pos + 1
        else:
            self.cursor_pos = (self.cursor_pos + 1) % self.size;
        if (self.skip_empty_option == True):
            if (self.options[self.cursor_pos] == None
                or self.options[self.cursor_pos] == ""):
                self._down()
        self.cursor_pos_x = 0;

    def _left(self):
        if (self.cursor_pos_x > 0):
            self.cursor_pos_x = self.cursor_pos_x - 1;

    def _right(self):
        self.cursor_pos_x = self.cursor_pos_x + 1;


    def show(self):
        while (True):
            self._display_menu();
            key = self._get_input()
            if (key == "up"):
                self._up()
            elif (key == "down"):
                self._down()
            if (key == "left"):
                self._left()
            elif (key == "right"):
                self._right()
            elif (key == "enter"):
                return (self.cursor_pos)

    def _display_menu(self):
        self._clear();
        size = os.get_terminal_size();
        size_x = size.columns;
        size_y = size.lines - 2;
        preview = self._preview();
        content_size, preview_size = utils.get_sizes(self.size,
                                                     preview.count("\n") + 1,
                                                     size_y,
                                                     self.preview_ratio)
        min_y, max_y, display_pos = utils.render(self.cursor_pos,
                                                 0,
                                                 self.size,
                                                 content_size // 2,
                                                 self.options)
        for i, option in enumerate(self.options[min_y:max_y]):
            element = option
            if (i == display_pos):
                min_x, max_x, display_pos_x = utils.render(self.cursor_pos_x,
                                                        0,
                                                        len(element),
                                                        len(element) // 2,
                                                        option)
                line = self.cursor + element[min_x:max_x]
            else:
                line = " " * len(self.cursor) + element
            print(line)
        print(preview)
    
    def _preview(self):
        if (len(self.preview_args) < self.cursor_pos):
            return 
        title = ""
        if (self.preview_title_function != None):
            title = self.preview_title_function(self.preview_args[self.cursor_pos])
        elif (self.preview_body_function != None):
            body = self.preview_body_function(self.preview_args[self.cursor_pos])
            return (title + "\n" + body);


    def _clear(self):
        os.system("clear")

    def _get_input(self) -> str:
        flag_have_getch = False
        flag_have_msvcrt = False
        try :
            import getch
            flag_have_getch = True
            first_char = getch.getch()
            if first_char == '\x1b': #arrow keys
                a=getch.getch()
                b=getch.getch()
                return {'[A': 'up', '[B': 'down', '[C': 'right', '[D': 'left' }[a+b]
            if ord(first_char) == 10:
                return  'enter'
            if ord(first_char) == 32:
                return  'space'
            else:
                return first_char #normal keys like abcd 1234
        except :
            pass
        
        try:
            import msvcrt
            flag_have_msvcrt = True
            key = msvcrt.getch()  # get keypress
            if key == b'\x1b':  # Esc key to exit
                return 'esc'
            elif key == b'\r':  # Enter key to select
                return 'enter'
            elif key == b'\x48':  # Up or Down arrow
                return  'up'
            elif key == b'\x50':  # Up or Down arrow
                return 'down'
            else:
                return key.decode('utf-8')
        except:
            pass
        
        if flag_have_getch == False and flag_have_msvcrt == False:
            print('\nErr:\tcan\'t get input \nFix:\tpip install getch')
            exit()
            first_char = getch.getch()
            print (first_char)
            if first_char == '\x1b': #arrow keys
                a=getch.getch()
                b=getch.getch()
                return {'[A': 'up', '[B': 'down', '[C': 'right', '[D': 'left' }[a+b]
            if ord(first_char) == 10:
                return  'enter'
            if ord(first_char) == 32:
                return  'space'

def preview(lst):
    return ("je suis la")

menu = Menu("fdddddddddddddddddddddddddddddddddddddddddddddddddddddddda", preview_body_function=preview);
menu.show()