"""
GUI for letter rotation encoding of strings
With slow encoding that makes GUI unresponsive!
MCS 260 Fall 2020 Lecture 38 (2pm)
"""
import tkinter
import tkinter.ttk
import rotcode
import time

class EncoderApp(tkinter.Tk):
    """GUI for controlling rotcode.rotate"""
    def __init__(self):
        """Initialize the window and add widgets"""
        super().__init__()  # Actually makes the main window
        self.title("LaserCode 9 Series X+")

        self.input_text = tkinter.StringVar()
        self.input_text.trace_add("write",lambda a,b,c:self.recalculate_output())
        self.output_text = tkinter.StringVar()

        self.input_label = tkinter.ttk.Label(self,text="Input:")
        self.input_label.grid(row=0,column=0,sticky="w",padx=8,pady=4)

        self.output_label = tkinter.ttk.Label(self,text="Output:")
        self.output_label.grid(row=1,column=0,sticky="w",padx=8,pady=4)

        self.input_entry = tkinter.ttk.Entry(self,width=50,textvariable=self.input_text)
        self.input_entry.grid(row=0,column=1,columnspan=2,sticky="ew",padx=8,pady=4)

        self.output_entry = tkinter.ttk.Entry(self,width=50,state="readonly",textvariable=self.output_text)
        self.output_entry.grid(row=1,column=1,columnspan=2,sticky="ew",padx=8,pady=4)

        self.steps_label = tkinter.ttk.Label(self,text="Steps:")
        self.steps_label.grid(row=2,column=0,sticky="w",padx=8,pady=4)

        self.steps = tkinter.IntVar()
        self.steps.trace_add("write",lambda a,b,c:self.recalculate_output())
        self.steps.trace_add("write",lambda a,b,c:self.update_steps_indicator())

        self.steps_slider = tkinter.ttk.Scale(self,from_=0,to=25,variable=self.steps)
        self.steps_slider.grid(row=2,column=1,sticky="ew",padx=8,pady=4)

        self.steps_indicator_content = tkinter.StringVar()

        self.steps_indicator = tkinter.ttk.Label(self,textvariable=self.steps_indicator_content,width=2)
        self.steps_indicator.grid(row=2,column=2,sticky="w",padx=8,pady=4)

        self.reverse_flag = tkinter.IntVar()
        self.reverse_flag.trace_add("write",lambda a,b,c:self.recalculate_output())

        self.reverse_check = tkinter.ttk.Checkbutton(self,text="Reverse string",variable=self.reverse_flag)
        self.reverse_check.grid(row=3,column=1,sticky="w",padx=8,pady=4)

        self.exit_button = tkinter.ttk.Button(self,text="Exit",command=exit)
        self.exit_button.grid(row=3,column=2,sticky="e",padx=8,pady=4)

        # Initialize the steps indicator to whatever the initial
        # value of the step slider is.
        self.update_steps_indicator()

    def update_steps_indicator(self):
        """Make steps indicator label consistent with the slider position"""
        self.steps_indicator_content.set(str(self.steps.get()))

    def recalculate_output(self):
        """callback for changes to input text entry box"""
        s = self.input_text.get()
        senc = rotcode.rotate(s,self.steps.get())
        time.sleep(1)
        if self.reverse_flag.get():
            # Reverse the encoded string
            senc = senc[::-1]
        self.output_text.set(senc)

app = EncoderApp()
app.mainloop()