using UnityEngine;

namespace BrewMonster
{
    /// <summary>
    /// Straight-line projectile movement.
    /// Mirrors C++ CGfxLinearMove exactly (A3DSkillGfxEvent2.cpp:22-52).
    /// 直线弹道移动，完全镜像C++ CGfxLinearMove。
    /// </summary>
    public class CGfxLinearMove : CGfxMoveBase
    {
        protected float m_fSpeed;
        private const float _fly_speed = 20.0f / 1000.0f; // units per ms, same as C++

        public CGfxLinearMove(GfxMoveMode mode) : base(mode) { }

        /// <summary>
        /// Initialize movement from host to target.
        /// 初始化从施法者到目标的移动。
        /// </summary>
        public override void StartMove(Vector3 vHost, Vector3 vTarget)
        {
            
            if (m_bArea)
            {
                CalcRange((vTarget - vHost).normalized);
                m_vPos = vHost + GetRandOff();
            }
            else
            {
                m_vPos = vHost;
            }

            m_vMoveDir = vTarget - m_vPos;
            float fDist = Normalize(ref m_vMoveDir);
            float fMax = _fly_speed * m_dwMaxFlyTime;


            if (fMax >= fDist)
            {
                m_fSpeed = _fly_speed;
            }
            else
            {
                m_fSpeed = fDist / m_dwMaxFlyTime;
            }
            
        }

        /// <summary>
        /// Tick movement. Returns true when target is hit.
        /// 更新移动。当命中目标时返回true。
        /// </summary>
        public override bool TickMove(uint dwDeltaTime, Vector3 vHostPos, Vector3 vTargetPos)
        {
            Vector3 oldPos = m_vPos;
            Vector3 vFlyDir = vTargetPos - m_vPos;
            float fDist = Normalize(ref vFlyDir);
            float fFlyDist = m_fSpeed * dwDeltaTime;


            if (fFlyDist >= fDist)
            {
                return true; // target hit / 命中目标
            }

            m_vPos += vFlyDir * fFlyDist;
            m_vMoveDir = vFlyDir;
            
            return false;
        }
    }
}