//
// Created by atdunbg on 2026/9/22.
//

#include <Engine/Renderer/Camera.h>
#include <Engine/Core/Window.h>

#include <glm/gtc/matrix_transform.hpp>

#include "GLFW/glfw3.h"

namespace Engine {

    void Camera::Update(Window& window, f32 deltaTime)
    {
        // 鼠标旋转（需显式启用，配合 cursor capture 使用）
        if (m_MouseLookEnabled)
        {
            f32 mouseDX = 0, mouseDY = 0;
            window.GetMouseDelta(mouseDX, mouseDY);

            if (mouseDX != 0 || mouseDY != 0)
            {
                m_Yaw += mouseDX * m_MouseSensitivity;
                m_Pitch -= mouseDY * m_MouseSensitivity;
                m_Pitch = glm::clamp(m_Pitch, -89.0f, 89.0f);
            }
        }

        UpdateBasis();

        f32 speed = m_MoveSpeed * deltaTime;
        if (window.IsKeyPressed(GLFW_KEY_W)) m_Position += m_Forward * speed;
        if (window.IsKeyPressed(GLFW_KEY_S)) m_Position -= m_Forward * speed;
        if (window.IsKeyPressed(GLFW_KEY_A)) m_Position -= m_Right * speed;
        if (window.IsKeyPressed(GLFW_KEY_D)) m_Position += m_Right * speed;
        if (window.IsKeyPressed(GLFW_KEY_SPACE)) m_Position.y += speed;
        if (window.IsKeyPressed(GLFW_KEY_LEFT_SHIFT)) m_Position.y -= speed;
    }

    void Camera::UpdateBasis()
    {
        m_Forward.x = cosf(glm::radians(m_Yaw)) * cosf(glm::radians(m_Pitch));
        m_Forward.y = sinf(glm::radians(m_Pitch));
        m_Forward.z = sinf(glm::radians(m_Yaw)) * cosf(glm::radians(m_Pitch));
        m_Forward = glm::normalize(m_Forward);

        m_Right = glm::normalize(glm::cross(m_Forward, glm::vec3(0, 1, 0)));
        m_Up = glm::normalize(glm::cross(m_Right, m_Forward));
    }

    glm::mat4 Camera::GetView() const
    {
        return glm::lookAt(m_Position, m_Position + m_Forward, m_Up);
    }

    glm::mat4 Camera::GetProjection(f32 aspect, f32 nearZ, f32 farZ) const
    {
        auto proj = glm::perspective(glm::radians(45.0f), aspect, nearZ, farZ);
        proj[1][1] *= -1.0f; // Vulkan Y 翻转

        // Vulkan clip 深度 [0,1]：z' = 0.5*z_clip + 0.5*w_clip。
        // perspective 的 w_clip = -z_eye，偏移折算进 z 系数
        //（注意：与 ortho 的公式不同，ortho 的 w=1 才能直接加到 [3][2]）
        proj[2][2] = proj[2][2] * 0.5f - 0.5f;
        proj[3][2] *= 0.5f;
        return proj;
    }

} // namespace Engine