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

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

#include <glm/gtc/matrix_transform.hpp>

#include "GLFW/glfw3.h"

namespace Engine {

    void Camera::Update(Window& window, ECS::TransformComponent& t, f32 deltaTime)
    {
        // 鼠标旋转：直接写实体旋转（yaw → rotation.y，pitch → rotation.x）
        if (m_MouseLookEnabled)
        {
            f32 mouseDX = 0, mouseDY = 0;
            window.GetMouseDelta(mouseDX, mouseDY);

            if (mouseDX != 0 || mouseDY != 0)
            {
                glm::vec3 rot = t.GetRotation();
                rot.y += mouseDX * m_MouseSensitivity;
                rot.x = glm::clamp(
                    rot.x - mouseDY * m_MouseSensitivity, -89.0f, 89.0f);
                t.SetRotation(rot);
            }
        }

        // 基向量由实体旋转决定（本地 -Z 为视线方向；应用顺序 Y→X，
        // 与 TransformComponent::Compose 一致；roll 不参与 FPS 相机）
        const glm::vec3& rot = t.GetRotation();
        const glm::mat3 r = static_cast<glm::mat3>(
            glm::rotate(glm::mat4(1.0f), glm::radians(rot.y),
                        glm::vec3(0, 1, 0)) *
            glm::rotate(glm::mat4(1.0f), glm::radians(rot.x),
                        glm::vec3(1, 0, 0)));
        const glm::vec3 forward = r * glm::vec3(0, 0, -1);
        const glm::vec3 right   = r * glm::vec3(1, 0, 0);

        f32 speed = m_MoveSpeed * deltaTime;
        if (window.IsKeyPressed(GLFW_KEY_W)) { t.SetPosition(t.GetPosition() + forward * speed); }
        if (window.IsKeyPressed(GLFW_KEY_S)) { t.SetPosition(t.GetPosition() - forward * speed); }
        if (window.IsKeyPressed(GLFW_KEY_A)) { t.SetPosition(t.GetPosition() - right * speed); }
        if (window.IsKeyPressed(GLFW_KEY_D)) { t.SetPosition(t.GetPosition() + right * speed); }
        if (window.IsKeyPressed(GLFW_KEY_SPACE)) { t.SetPosition(t.GetPosition() + glm::vec3(0, speed, 0)); }
        if (window.IsKeyPressed(GLFW_KEY_LEFT_SHIFT)) { t.SetPosition(t.GetPosition() - glm::vec3(0, speed, 0)); }
    }

    glm::mat4 Camera::GetView(const ECS::TransformComponent& t) const
    {
        // 相机作为实体：视图 = 世界矩阵的逆（无重复位姿状态）
        return glm::inverse(t.World());
    }

    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