using Core.Input;
using TowerDefense.Level;
using TowerDefense.Towers;
using TowerDefense.UI.HUD;
using UnityEngine;
using UnityInput = UnityEngine.Input;
using State = TowerDefense.UI.HUD.GameUI.State;

namespace TowerDefense.Input
{
    [RequireComponent(typeof(GameUI))]
    public class TowerDefenseKeyboardMouseInput : KeyboardMouseInput
    {
        /// <summary>
        /// Cached eference to gameUI
        /// </summary>
        GameUI m_GameUI;

        /// <summary>
        /// 是否处于拖动状态。
        /// </summary>
        protected bool isInDragState = false;

        /// <summary>
        /// Register input events
        /// </summary>
        protected override void OnEnable()
        {
            base.OnEnable();

            m_GameUI = GetComponent<GameUI>();

            if (InputController.instanceExists)
            {
                InputController controller = InputController.instance;

                controller.tapped += OnTap;
                controller.mouseMoved += OnMouseMoved;

                // River Add for Mouse Start Drag & Draged.
                controller.startedDrag += OnStartDrag;
                controller.dragged += this.OnDrag;
                controller.released += this.OnEndDrag;
            }
        }


        /// <summary>
        /// Deregister input events
        /// </summary>
        protected override void OnDisable()
        {
            if (!InputController.instanceExists)
            {
                return;
            }

            InputController controller = InputController.instance;

            controller.tapped -= OnTap;
            controller.mouseMoved -= OnMouseMoved;

            controller.startedDrag -= this.OnStartDrag;
            controller.dragged -= this.OnDrag;
            controller.released -= this.OnEndDrag;
        }

        /// <summary>
        /// Handle camera panning behaviour
        /// </summary>
        protected override void Update()
        {
            base.Update();

            // Escape handling
            if (UnityInput.GetKeyDown(KeyCode.Escape))
            {
                switch (m_GameUI.state)
                {
                    case State.Normal:
                        if (m_GameUI.isTowerSelected)
                        {
                            m_GameUI.DeselectTower();
                        }
                        else
                        {
                            m_GameUI.Pause();
                        }
                        break;
                    case State.BuildingWithDrag:
                    case State.Building:
                        m_GameUI.CancelGhostPlacement();
                        break;
                }
            }

            // place towers with keyboard numbers
            if (LevelManager.instanceExists)
            {
                int towerLibraryCount = LevelManager.instance.towerLibrary.Count;

                // find the lowest value between 9 (keyboard numbers)
                // and the amount of towers in the library
                int count = Mathf.Min(9, towerLibraryCount);
                KeyCode highestKey = KeyCode.Alpha1 + count;

                for (var key = KeyCode.Alpha1; key < highestKey; key++)
                {
                    // add offset for the KeyCode Alpha 1 index to find correct keycodes
                    if (UnityInput.GetKeyDown(key))
                    {
                        Tower controller = LevelManager.instance.towerLibrary[key - KeyCode.Alpha1];
                        if (m_GameUI.isBuilding)
                        {
                            m_GameUI.CancelGhostPlacement();
                        }
                        GameUI.instance.SetToBuildMode(controller);
                        GameUI.instance.TryMoveGhost(InputController.instance.basicMouseInfo);
                        break;
                    }
                }

                // special case for 0 mapping to index 9
                if (count < 10 && UnityInput.GetKeyDown(KeyCode.Alpha0))
                {
                    Tower controller = LevelManager.instance.towerLibrary[9];
                    GameUI.instance.SetToBuildMode(controller);
                    GameUI.instance.TryMoveGhost(InputController.instance.basicMouseInfo);
                }
            }
        }

        /// <summary>
        /// Ghost follows pointer
        /// </summary>
        void OnMouseMoved(PointerInfo pointer)
        {
            // We only respond to mouse info
            var mouseInfo = pointer as MouseCursorInfo;

            if ((mouseInfo != null) && (m_GameUI.isBuilding))
            {
                m_GameUI.TryMoveGhost(pointer, false);
            }
        }

        protected virtual void OnStartDrag(PointerActionInfo pointer)
        {
            // select towers
            m_GameUI.TrySelectTower(pointer);
            // River: 为了开始拖动后可以直接显示GhostTower
            m_GameUI.TryMoveGhost(pointer, false);

            this.isInDragState = true;
        }

        protected override void OnDrag(PointerActionInfo pointer)
        {
            if ((pointer != null) && (m_GameUI.isBuilding))
            {
                m_GameUI.TryMoveGhost(pointer, false);
            }
        }

        protected void OnEndDrag(PointerActionInfo pointer)
        {
            // EndDrag 只能放置相关的GhostTower.
            if (this.isInDragState)
                m_GameUI.onEndTowerDrag(pointer);
            //m_GameUI.TryPlaceTower(pointer);

            this.isInDragState = false;
        }


        /// <summary>
        /// Select towers or position ghosts
        /// </summary>
        void OnTap(PointerActionInfo pointer)
        {
            // We only respond to mouse info
            var mouseInfo = pointer as MouseButtonInfo;

            if (mouseInfo != null && !mouseInfo.startedOverUI)
            {
                if (m_GameUI.isBuilding)
                {
                    if (mouseInfo.mouseButtonId == 0) // LMB confirms
                    {
                        if (m_GameUI.TryPlaceTower(pointer))
                        {
                            // 开启相应的兵线:
                            Tower tw = m_GameUI.FindTowerWithGridIdx(m_GameUI.currentGrid.x, m_GameUI.currentGrid.y);
                            if ((tw != null) && (tw.bInAttackMode))
                                LevelManager.instance.startWaveLine(m_GameUI.currentGrid.x, false, tw.ElfId);
                        }
                    }
                    else // RMB cancels
                    {
                        m_GameUI.CancelGhostPlacement();
                    }
                }
                else
                {
                    if (mouseInfo.mouseButtonId == 0)
                    {
                        // select towers
                        m_GameUI.TrySelectTower(pointer);
                        // River: 为了TAP后立刻显示出来相关的Ghost.
                        m_GameUI.TryMoveGhost(pointer, false);

                    }
                }
            }
        }
    }
}