# difference_of_squares_final.py
from manim import *

class SquareDifference(Scene):
    def construct(self):
        # 高清配置
        config.frame_width = 16
        config.frame_height = 9
        config.pixel_height = 1440
        config.pixel_width = 2560
        
        # 参数配置
        a = 4
        b = 1
        colors = {
            "a": "#1F77B4",
            "b": "#FF7F0E",
            "text": "#FFFFFF",
            "bg": "#2E2E2E"
        }
        self.camera.background_color = colors["bg"]
        step_delay = 2.5

        # ========== 标题部分 ==========
        title = Text("东师理想数学课件生成助手", 
                   font_size=48,
                   color=colors["text"],
                   weight=BOLD,
                   stroke_width=8,
                   stroke_color=BLACK)
        
        sub_title = Text("平方差公式可视化演示", 
                       font_size=32, 
                       color=colors["text"],
                       stroke_width=4,
                       stroke_color=BLACK).next_to(title, DOWN)
        
        self.play(
            Write(title, run_time=1.5),
            FadeIn(sub_title, shift=UP),
            run_time=2
        )
        self.wait(step_delay)
        self.play(
            FadeOut(title, shift=UP),
            FadeOut(sub_title, shift=DOWN),
            run_time=1.5
        )

        # ========== 公式推导部分 ==========
        formula_steps = VGroup(
            MathTex("(", "a", "+", "b", ")(", "a", "-", "b", ")", font_size=40),
            MathTex("=", "a", "^2", "-", "b", "^2", font_size=40),
            MathTex("=", f"{a**2}", "-", f"{b**2}", font_size=40),
            MathTex("=", f"{(a+b)*(a-b)}", font_size=48, color=GREEN)
        ).arrange(DOWN, aligned_edge=LEFT, buff=0.8)
        
        formula_board = SurroundingRectangle(
            formula_steps, 
            color=WHITE, 
            stroke_width=2,
            fill_color=BLACK,
            fill_opacity=0.7,
            corner_radius=0.2
        )
        
        self.play(
            DrawBorderThenFill(formula_board),
            FadeIn(formula_steps, shift=UP),
            run_time=2
        )
        self.wait(step_delay)

        # ========== 坐标系部分（最终修复） ==========
        # 使用新版背景线直接生成网格
        axes = Axes(
            x_range=[0, a+b+1, 1],
            y_range=[0, a+b+1, 1],
            x_length=8,
            y_length=6,
            axis_config={
                "color": colors["text"],
                "stroke_width": 3,
                "include_numbers": True
            }
        ).shift(DOWN*0.5)
        

        # 大正方形动画
        big_square = Rectangle(
            width=a+b,
            height=a+b,
            color=colors["a"],
            fill_opacity=0.4,
            stroke_width=4
        ).move_to(axes.c2p((a+b)/2, (a+b)/2))
        
        self.play(
            formula_board.animate.scale(0.8).to_edge(UP, buff=0.5),
            Create(axes, run_time=2),
            DrawBorderThenFill(big_square),
            run_time=2
        )
        self.wait(step_delay)


        # ========== 剩余动画部分 ==========
        # 垂直分割线
        v_line = Line(
            start=axes.c2p(a, 0),
            end=axes.c2p(a, a+b),
            color=colors["text"],
            stroke_width=4
        )
        v_label = MathTex("a", 
                        color=colors["text"],
                        stroke_width=3,
                        stroke_color=BLACK).next_to(v_line, RIGHT, buff=0.2)
        
        # 水平分割线
        h_line = Line(
            start=axes.c2p(0, a),
            end=axes.c2p(a+b, a),
            color=colors["text"],
            stroke_width=4
        )
        h_label = MathTex("a", 
                        color=colors["text"],
                        stroke_width=3,
                        stroke_color=BLACK).next_to(h_line, UP, buff=0.2)
        
        self.play(
            Create(v_line),
            Write(v_label),
            Create(h_line),
            Write(h_label),
            run_time=2
        )
        self.wait(step_delay)

        # ========== 面积计算部分 ==========
        part_a = Rectangle(
            width=a,
            height=a,
            color=colors["a"],
            fill_opacity=0.6
        ).move_to(axes.c2p(a/2, a/2))
        
        part_b = Rectangle(
            width=b,
            height=a+b,
            color=colors["b"],
            fill_opacity=0.6
        ).move_to(axes.c2p(a + b/2, (a+b)/2))
        
        self.play(
            Transform(big_square, part_a),
            FadeIn(part_b),
            run_time=2
        )
        self.wait(step_delay)

        # 移动并计算面积差
        moved_part = part_b.copy().shift(DOWN*b)
        area_diff = Rectangle(
            width=b,
            height=2*b,
            color=RED,
            fill_opacity=0.3
        ).move_to(axes.c2p(a + b/2, a - b))
        
        self.play(
            part_b.animate.shift(DOWN*b),
            FadeIn(area_diff),
            run_time=2
        )
        self.wait(step_delay)

        # ========== 最终联动 ==========
        final_formula = formula_steps[-1].copy()
        final_formula.generate_target()
        final_formula.target.scale(1.5).move_to(ORIGIN)
        
        self.play(
            MoveToTarget(final_formula),
            FadeOut(axes),
            FadeOut(part_a),
            FadeOut(part_b),
            FadeOut(area_diff),
            run_time=2
        )
        self.wait(step_delay*2)

        # 结束动画
        self.play(
            final_formula.animate.scale(0.5).to_edge(DOWN, buff=1),
            run_time=1.5
        )
        self.wait(2)

        # 版权信息
        copyright = Text("© 东师理想 版权所有", 
                      font_size=24, 
                      color=colors["text"],
                      stroke_width=2,
                      stroke_color=BLACK).to_edge(DOWN, buff=0.3)
        self.play(Write(copyright), run_time=1)
        self.wait(3)