# tk_softbody.py
# still has an instability issues?

import tkinter as tk
import math

WIDTH, HEIGHT = 600, 600
softbodies = []
dragged_body = None
drag_offset_x = 0
drag_offset_y = 0

def create_softbody(x, y, radius, points_count):
    body_points = []
    body_springs = []
    
    for i in range(points_count):
        angle = 2 * math.pi * i / points_count
        px = x + radius * math.cos(angle)
        py = y + radius * math.sin(angle)
        body_points.append({'x': px, 'y': py, 'oldx': px, 'oldy': py, 'pinned': False})
    
    for i in range(points_count):
        p1 = body_points[i]
        p2 = body_points[(i + 1) % points_count]
        body_springs.append({'p1': p1, 'p2': p2, 'length': math.hypot(p2['x']-p1['x'], p2['y']-p1['y'])})
    
    for i in range(points_count // 2):
        p1 = body_points[i]
        p2 = body_points[i + points_count // 2]
        body_springs.append({'p1': p1, 'p2': p2, 'length': math.hypot(p2['x']-p1['x'], p2['y']-p1['y'])})
    
    return {
        'points': body_points,
        'springs': body_springs,
        'radius': radius,
        'flip_count': 0,
        'last_area': 0,
        'original_points': [{'x': px, 'y': py} for px, py in [(p['x'], p['y']) for p in body_points]]
    }

def calculate_area(points):
    area = 0.0
    n = len(points)
    for i in range(n):
        x_i = points[i]['x']
        y_i = points[i]['y']
        x_j = points[(i+1)%n]['x']
        y_j = points[(i+1)%n]['y']
        area += (x_i * y_j) - (x_j * y_i)
    return abs(area) / 2.0

def reset_body(body):
    cx = sum(p['x'] for p in body['points']) / len(body['points'])
    cy = sum(p['y'] for p in body['points']) / len(body['points'])
    
    for i, point in enumerate(body['points']):
        original = body['original_points'][i]
        point['x'] = cx + (original['x'] - body['original_points'][0]['x'])
        point['y'] = cy + (original['y'] - body['original_points'][0]['y'])
        point['oldx'] = point['x']
        point['oldy'] = point['y']
    
    body['flip_count'] = 0
    body['last_area'] = calculate_area(body['points'])

def update_physics():
    for body in softbodies:
        current_area = calculate_area(body['points'])
        
        if body['last_area'] > 0 and current_area < body['last_area'] * 0.3:  # Significant area reduction
            body['flip_count'] += 1
        else:
            body['flip_count'] = max(0, body['flip_count'] - 0.1)
        
        body['last_area'] = current_area
        
        if body['flip_count'] >= 2:
            reset_body(body)
            continue
        
        for point in body['points']:
            if not point['pinned']:
                vx = (point['x'] - point['oldx']) * 0.99
                vy = (point['y'] - point['oldy']) * 0.99
                point['oldx'] = point['x']
                point['oldy'] = point['y']
                point['x'] += vx
                point['y'] += vy
                point['y'] += 0.5
                
                if point['x'] < 5: point['x'], point['oldx'] = 5, point['x'] + vx*0.5
                if point['x'] > WIDTH-5: point['x'], point['oldx'] = WIDTH-5, point['x'] + vx*0.5
                if point['y'] < 5: point['y'], point['oldy'] = 5, point['y'] + vy*0.5
                if point['y'] > HEIGHT-5: point['y'], point['oldy'] = HEIGHT-5, point['y'] + vy*0.5
    
    for _ in range(3):
        for body in softbodies:
            for spring in body['springs']:
                p1 = spring['p1']
                p2 = spring['p2']
                dx = p2['x'] - p1['x']
                dy = p2['y'] - p1['y']
                distance = math.hypot(dx, dy)
                diff = 0
                if distance:
                    diff = (spring['length'] - distance) / distance
                if not p1['pinned']:
                    p1['x'] -= dx * diff * 0.5
                    p1['y'] -= dy * diff * 0.5
                if not p2['pinned']:
                    p2['x'] += dx * diff * 0.5
                    p2['y'] += dy * diff * 0.5
    
    for i, body1 in enumerate(softbodies):
        for j, body2 in enumerate(softbodies):
            if i != j:
                for point in body1['points']:
                    for other_point in body2['points']:
                        dx = other_point['x'] - point['x']
                        dy = other_point['y'] - point['y']
                        distance = math.hypot(dx, dy)
                        if distance < 10:
                            if distance == 0: distance = 0.001
                            force = (10 - distance) / distance * 0.5
                            point['x'] -= dx * force
                            point['y'] -= dy * force

def draw():
    canvas.delete("all")
    for body in softbodies:
        for spring in body['springs']:
            p1 = spring['p1']
            p2 = spring['p2']
            canvas.create_line(p1['x'], p1['y'], p2['x'], p2['y'], fill="#d0d0ff", width=2)
        
        for point in body['points']:
            color = "red" if point['pinned'] else "#4444ff"
            canvas.create_oval(point['x']-3, point['y']-3, point['x']+3, point['y']+3, fill=color, outline="")

def physics_loop():
    update_physics()
    draw()
    root.after(1, physics_loop)

def on_click(event):
    global dragged_body, drag_offset_x, drag_offset_y
    for body in softbodies:
        cx = sum(p['x'] for p in body['points']) / len(body['points'])
        cy = sum(p['y'] for p in body['points']) / len(body['points'])
        if math.hypot(event.x - cx, event.y - cy) < body['radius']:
            dragged_body = body
            drag_offset_x = event.x - cx
            drag_offset_y = event.y - cy
            for point in body['points']:
                point['pinned'] = True
            return

def on_drag(event):
    global dragged_body, drag_offset_x, drag_offset_y
    if dragged_body:
        cx = sum(p['x'] for p in dragged_body['points']) / len(dragged_body['points'])
        cy = sum(p['y'] for p in dragged_body['points']) / len(dragged_body['points'])
        new_cx = event.x - drag_offset_x
        new_cy = event.y - drag_offset_y
        dx = new_cx - cx
        dy = new_cy - cy
        for point in dragged_body['points']:
            point['x'] += dx
            point['y'] += dy
            point['oldx'] = point['x']
            point['oldy'] = point['y']

def on_release(event):
    global dragged_body
    if dragged_body:
        for point in dragged_body['points']:
            point['pinned'] = False
        dragged_body = None

root = tk.Tk()
canvas = tk.Canvas(root, width=WIDTH, height=HEIGHT, bg='white')
canvas.pack()

softbodies = [
    create_softbody(200, 200, 50, 12),
    create_softbody(400, 400, 70, 16)
]

canvas.bind("<Button-1>", on_click)
canvas.bind("<B1-Motion>", on_drag)
canvas.bind("<ButtonRelease-1>", on_release)

physics_loop()
root.mainloop()