using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class AI : Character
{
    public List<Cell> frontier = new List<Cell>();
    public List<Cell> explored = new List<Cell>();
    public int sensingRange = 6;        //感知范围
    public int attackRange = 1;         //攻击范围
    public int attackCost = 4;          //攻击消耗
    public AISkill skill;
    Character goal = null;
    Cell cell;
    float timer = 0.5f;
    public IEnumerator ApplyAI()
    {
        //Debug.Log("StartAI");
        if(FindNearestEnemy() > sensingRange)                   //观测周围是否有敌人
            yield return null;
        //Debug.Log("The goal is " + goal.transform.position.x + "," + goal.transform.position.y);
        RaycastHit2D hit = Physics2D.Raycast(transform.position,Vector2.up,1.0f,LayerMask.GetMask("Cells"));
        cell = hit.collider.GetComponent<Cell>();
        cell.parent = null;
        cell.gCost = 0;
        cell.hCost = 1000;
        frontier.Add(cell);
        yield return StartCoroutine(SearchEnemy());                    //发现敌人并向敌人移动
        //TestThePath(path);
    }
    IEnumerator SearchEnemy()
    {
        int nearestCell = 1000;
        List<Cell> path = new List<Cell>();
        Cell endNode = null;
        while(frontier.Count != 0)
        {
            Cell node = LowestCost();                   //总是找出fCost最低的节点
            //Debug.Log("Node =" + node.transform.position.x + "," + node.transform.position.y);
            frontier.Remove(node);
            //若找到目标所在Cell，则返回其父结点
            if(node.currentCharacter != null && node.currentCharacter.groupNumber != groupNumber)
            {
                //Debug.Log(node.transform.position.x + "," + node.transform.position.y);
                endNode = node.parent;
                break;
            }
            //Debug.Log("node is " + node.transform.position.x + "," +node.transform.position.y + " hCost is " + node.hCost);
            //找到离目标预测最近的单元格
            if(node.hCost < nearestCell)
            {
                endNode = node;
                nearestCell = node.hCost;
            }
            explored.Add(node);
            List<Cell> neighbors = node.GetNeighbor();
            foreach (var neighbor in neighbors)
            {
                if(!frontier.Contains(neighbor) && !explored.Contains(neighbor))
                {
                    if(neighbor.currentCharacter != null && neighbor.currentCharacter.groupNumber == groupNumber)
                        continue;
                    neighbor.parent = node;
                    neighbor.CalculateCosts(goal.transform.position);
                    if(neighbor.gCost <= maxMovement)
                        frontier.Add(neighbor);
                }
            }
        }
        // if(endNode != null)
        //     Debug.Log("endNode is " + endNode.transform.position.x + "," +endNode.transform.position.y);
        int count = 0;
        // if(!found)
        //     endNode = frontier[frontier.Count - 1];
        while(endNode != null)
        {
            path.Add(endNode);
            endNode = endNode.parent;
            count ++;
            if(count > 10) break;
        }
        frontier.Clear();
        explored.Clear();
        //if(found == true)
        {
            for(int i = 0; i < attackRange - 1; i++)
                path.RemoveAt(0);
            path.Reverse();
            if(path.Count > 0)
                path.RemoveAt(0);
            //Debug.Log("path.Count = " + path.Count);
        }
        yield return StartCoroutine(ActionAI(path));
    }
    void TestThePath(List<Cell> path)   //测试用函数
    {
        Debug.Log("The path :");
        foreach(var node in path)
        {
            Debug.Log(node.transform.position.x + "," + node.transform.position.y);
        }
    }
    int FindNearestEnemy()      //找到最近距离的敌人
    {
        int minDistance = 1000;
        GameObject[] pieces = GameManager.instance.pieces;
        foreach(var piece in pieces)
        {
            Character character = piece.GetComponent<Character>();
            int distance = GameSettlement.Manhattan(transform.position,character.transform.position);
            if(character.groupNumber != groupNumber && distance < minDistance)
            {
                minDistance = distance;
                goal = character;
            }
        }
        //Debug.Log("minDistance = " + minDistance);
        return minDistance;
    }
    Cell LowestCost()       //找出frontier里fCost最低的节点
    {
        Cell lowestCost = frontier[0];
        foreach(var node in frontier)
        {
            if(node.fCost < lowestCost.fCost)
                lowestCost = node;
        }
        return lowestCost;
    }
    IEnumerator ActionAI(List<Cell> path)
    {
        Selected();
        //移动阶段
        foreach(var node in path)
        {
            Vector2 position1 = cell.transform.position;
            Vector2 position2 = node.transform.position;
            float deltaX = position2.x - position1.x;
            float deltaY = position2.y - position1.y;
            Vector2 deviation = new Vector2(deltaX,deltaY);
            yield return StartCoroutine(Move(deviation, 0.1f));
            cell = node;
        }
        //攻击阶段
        if(GameSettlement.Manhattan(goal.transform.position,transform.position) <= attackRange)
            while(currentMovement >= attackCost)
            {
                yield return new WaitForSeconds(0.2f);
                AIAttack();
            }
        yield return new WaitForSeconds(2 * timer);
        Cancel();
    }
    void AIAttack()
    {
        if(skill.CheckRequest(currentMana, currentMovement, goal))
        {
            Debug.Log("AISkill released");
            skill.ApplySkill(this, goal);
            return;
        }
        int damage = GameSettlement.AIAttackSettlement(this, goal);
        goal.ChangeHealth(damage);
        goal.ChangePoise(-str);
        ChangeMovement(-attackCost);
        ChangeMana(inte/3 + san/5);
        //buffManager.ApplyActiveSpecial(goal);
        goal.buffManager.ApplyPassiveSpecial(this);
    }
    public override void Selected()         //AI不需要武器
    {
        if(GameManager.instance.selected != null) return;
        if(GameManager.instance.currentGroup != groupNumber)
            return;
        animator.SetFloat("selected", 1);
        GameManager.instance.SetSelected(gameObject.GetComponent<Character>());
        movementBar.SetMovementActive(true);
    }
    public override void Cancel()       //AI不需要武器
    {
        animator.SetFloat("selected", 0);
        GameManager.instance.SetSelected(null);
        movementBar.SetMovementActive(false);
    }
    protected override void OnMouseOver()
    {
        //鼠标右键点击查看角色信息
        if(Input.GetMouseButton(1) && GameManager.instance.GetSelected() == null)
        {
            GameManager.instance.CheckDetailInformation(str,inte,dex,san,vig,def,
            currentHealth,maxHealth,currentPoise,maxPoise,currentMana,maxMana);
        }
    }
}