from tkinter import *
from R2Graph import *
import math
import numpy as np
from sklearn.tree import DecisionTreeRegressor

def main():
    points = []
    mouseButtons = []
    objectIDs = []
    funcDrawn = False
    
    scaleX = 40.; scaleY = 40.
    root = Tk()
    root.title("Plot Function")
    root.geometry("800x600")
    panel = Frame(root)
    drawButton = Button(panel, text="Draw")
    clearButton = Button(panel, text="Clear")
    drawArea = Canvas(root, bg="white")
    panel.pack(side=TOP, fill=X)
    drawButton.pack(side=LEFT, padx=4, pady=4)    
    clearButton.pack(side=LEFT, padx=4, pady=4)
    drawArea.pack(side=TOP, fill=BOTH, expand=True, padx=4, pady=4)

    degree = 1    
    treeModel = None
    depth = 3
    
    w = np.zeros(depth + 1)
    
    degreeLabel = Label(panel, text="Degree:")
    degreeScale = Scale(panel, from_=1, to=10, orient=HORIZONTAL)
    degreeScale.set(degree)
    
    depthLabel = Label(panel, text="Depth:")
    depthScale = Scale(panel, from_=2, to=20, orient=HORIZONTAL)
    depthScale.set(depth)
    
    degreeLabel.pack(side=LEFT, padx=4, pady=4)
    degreeScale.pack(side=LEFT, padx=4, pady=4)
    depthLabel.pack(side=LEFT, padx=4, pady=4)
    depthScale.pack(side=LEFT, padx=4, pady=4)
    
    root.update()
    
    def map(t):
        w = drawArea.winfo_width()
        h = drawArea.winfo_height()
        centerX = w/2.
        centerY = h/2.
        x = centerX + t.x*scaleX
        y = centerY - t.y*scaleY
        return (x, y)
        
    def invmap(p):
        w = drawArea.winfo_width()
        h = drawArea.winfo_height()
        centerX = w/2.
        centerY = h/2.
        x = (p[0] - centerX)/scaleX
        y = (centerY - p[1])/scaleY
        return R2Point(x, y)
        
    def xMin():
        w = drawArea.winfo_width()
        return (-(w/scaleX)/2.)
    def xMax():
        return (-xMin())
    def yMin():
        w = drawArea.winfo_height()
        return (-(w/scaleY)/2.)
    def yMax():
        return (-yMin())
        
    def drawGrid():
        ix0 = int(xMin())
        ix1 = int(xMax())
        x = ix0
        while x <= ix1:
            if x != 0:
                p0 = map(R2Point(x, yMin()))
                p1 = map(R2Point(x, yMax()))
                drawArea.create_line(p0, p1, fill="lightGray", width=1)
            x += 1

        iy0 = int(yMin())
        iy1 = int(yMax())
        y = iy0
        while y <= iy1:
            if y != 0:
                p0 = map(R2Point(xMin(), y))
                p1 = map(R2Point(xMax(), y))
                drawArea.create_line(p0, p1, fill="lightGray", width=1)
            y += 1
            
        # Draw x-axis
        drawArea.create_line(
            map(R2Point(xMin(), 0.)), map(R2Point(xMax(), 0.)),
            fill="black", width=2
        )    
        # Draw y-axis
        drawArea.create_line(
            map(R2Point(0., yMin())), map(R2Point(0., yMax())),
            fill="black", width=2
        )
        
    def func(x):
        if treeModel == None:
            return 0.
        X = np.array([[x]])
        y = treeModel.predict(X)[0]
        return y
        
    def mse(x):
        nonlocal w
        if treeModel == None:
            return 0.
        return np.polyval(w, x)

    def plotFunction(f, color="blue", width = 1):
        t = R2Point(xMin(), f(xMin()))
        dx = 0.05
        path = []
        while t.x <= xMax():
            path.append(map(t))
            t.x += dx
            t.y = f(t.x)
        lineID = drawArea.create_line(path, fill=color, width=width)
        objectIDs.append(lineID)
        
    def onMouseRelease(e):
        # print("Mouse release event:", e)
        p = (e.x, e.y)
        t = invmap(p)
        points.append(t)
        mouseButtons.append(e.num)
        drawPoint(t, e.num)
        
    def drawPoint(t, mouseButton = 1):
        vx = R2Vector(0.1, 0.)
        vy = R2Vector(0., 0.1)
        color = "red"
        if mouseButton == 2:
            color = "green"
        elif mouseButton == 3:
            color = "magenta"
        '''
        lineID = drawArea.create_line(
            map(t - vx), map(t + vx), fill=color, width=3
        )
        objectIDs.append(lineID)    
        lineID = drawArea.create_line(
            map(t - vy), map(t + vy), fill=color, width=3
        )    
        objectIDs.append(lineID)
        '''
        pointID = drawArea.create_oval(
            map(t - vx + vy), map(t + vx - vy), 
            fill=color, outline=color
        )
        
    def drawPoints():
        for i in range(len(points)):
            drawPoint(points[i], mouseButtons[i])
        
    def onDraw():
        nonlocal treeModel, depth, w, degree, funcDrawn
        degree = degreeScale.get()                
        x = np.array(
            [[p.x] for p in points]
        )
        y = np.array(
            [p.y for p in points]
        )
        depth = depthScale.get()
        treeModel = DecisionTreeRegressor(max_depth = depth)
        treeModel.fit(x, y)
        
        # MSE function
        X = np.array(
            [      
                [p.x**d for d in range(degree, -1, -1)]
                for p in points
            ]
        )
        w = np.linalg.pinv(X) @ y       
        
        clearPicture()
        drawPoints()
        plotFunction(func, color = "green", width = 3)
        plotFunction(mse, color = "blue", width = 1)
        funcDrawn = True
        
    def clearPicture():
        for i in objectIDs:
            drawArea.delete(i)
        objectIDs.clear()
            
    def onClear():
        nonlocal funcDrawn
        clearPicture()
        points.clear()
        mouseButtons.clear()
        funcDrawn = False
        treeModel = None
        
    def onConfigure(e):
        drawArea.delete("all")
        drawGrid()
        drawPoints()        
        if funcDrawn:
            plotFunction(func, color = "green", width = 3)
            plotFunction(mse, color = "blue", width = 1)

    drawButton.configure(command = onDraw)
    clearButton.configure(command = onClear)
    drawArea.bind("<ButtonRelease-1>", onMouseRelease)
    drawArea.bind("<ButtonRelease-2>", onMouseRelease)
    drawArea.bind("<ButtonRelease-3>", onMouseRelease)
    drawArea.bind("<Configure>", onConfigure)
    
    drawGrid()
    # plotFunction(func)
    
    root.mainloop()
    
if __name__ == "__main__":
    main()