/**
 * Copyright(c) Live2D Inc. All rights reserved.
 *
 * Use of this source code is governed by the Live2D Open Software license
 * that can be found at https://www.live2d.com/eula/live2d-open-software-license-agreement_en.html.
 */

#include "TouchManager.h"

TouchManager::TouchManager()
    : lastX(0)
    , lastY(0)
    , lastX1(0)
    , lastY1(0)
    , lastX2(0)
    , lastY2(0)
    , lastTouchDist(0)
    , deltaX(0)
    , deltaY(0)
    , scale(1)
{ }

/*
 * タッチ開始時イベント
 * @param x
 * @param deviceY
 */
void TouchManager::touchesBegan(float x, float y)
{
    lastX = x;
    lastY = y;
    startX = x;
    startY = y;
    lastTouchDist = -1;
    flipAvailable = true;
    touchSingle = true;
}

/*
 * タッチ開始時イベント。
 * @param x1
 * @param y1
 * @param x2
 * @param y2
 */
void TouchManager::touchesBegan(float x1, float y1, float x2, float y2)
{
    float dist = distance(x1, y1, x2, y2);
    float centerX = (x1 + x2) * 0.5f;
    float centerY = (y1 + y2) * 0.5f;

    lastX1 = x1;
    lastY1 = y1;
    lastX2 = x2;
    lastY2 = y2;

    lastX = centerX;
    lastY = centerY;
    startX = centerX;
    startY = centerY;
    lastTouchDist = dist;
    flipAvailable = true;
    touchSingle = false;
}

void TouchManager::touchesMoved(axis::Point touches[], int num)
{
    // 前回のクリック位置に最も近いものを選びだす
    // pt1、pt2の両点への距離の和が最小となる点の組み合わせを総当たりで探す
    int index1, index2, minDist2 = 999999999;
    index1 = 0;
    index2 = 1;
    for (int i1 = 0; i1 < num; i1 ++)
    {
        axis::Point pp1 = touches[i1];

        for (int i2 = 0; i2 < num; i2++)
        {
            if (i1 == i2) continue ;

            axis::Point pp2 = touches[i2];

            int distTotal = ((lastX1 - pp1.x) * (lastX1 - pp1.x) + (lastY1 - pp1.y) * (lastY1 - pp1.y))
                    + ((lastX2 - pp2.x) * (lastX2 - pp2.x) + (lastY2 - pp2.y) * (lastY2 - pp2.y));

            if (distTotal < minDist2)
            {
                minDist2 = distTotal;
                index1 = i1;
                index2 = i2;
            }
        }
    }

    if (minDist2 > 70 * 70 * 2 && num > 2) return; // 処理しない
    // pt2に一番近い点
    axis::Point pt1 = touches[index1];
    axis::Point pt2 = touches[index2];

    touchesMoved(pt1.x, pt1.y, pt2.x, pt2.y);
}

/*
 * ドラッグ時のイベント
 * @param deviceX
 * @param deviceY
 */
void TouchManager::touchesMoved(float deviceX, float deviceY)
{
    lastX = deviceX;
    lastY = deviceY;
    lastTouchDist = -1;
    touchSingle = true;
}

/*
 * ドラッグ時のイベント
 * @param x1
 * @param y1
 * @param x2
 * @param y2
 */
void TouchManager::touchesMoved(float x1, float y1, float x2, float y2)
{
    float dist = distance(x1, y1, x2, y2);
    float centerX = (x1 + x2) * 0.5f;
    float centerY = (y1 + y2) * 0.5f;

    if (lastTouchDist > 0)
    {
        scale = (float)pow(dist / lastTouchDist, 0.75);
        deltaX = calcShift(x1 - lastX1, x2 - lastX2);
        deltaY = calcShift(y1 - lastY1, y2 - lastY2);
    }
    else
    {
        scale = 1;
        deltaX = 0;
        deltaY = 0;
    }

    lastX = centerX;
    lastY = centerY;
    lastX1 = x1;
    lastY1 = y1;
    lastX2 = x2;
    lastY2 = y2;
    lastTouchDist = dist;
    touchSingle = false;
}

/*
 * フリックした距離
 * @return
 */
float TouchManager::getFlickDistance()
{
    return distance(startX, startY, lastX, lastY);
}

/*
 * 点1から点2への距離を求める
 * @param p1x
 * @param p1y
 * @param p2x
 * @param p2y
 * @return
 */
float TouchManager::distance(float x1, float y1, float x2, float y2)
{
    return (float)sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));
}

/*
 * 二つの値から、移動量を求める。
 * 違う方向の場合は移動量０。同じ方向の場合は、絶対値が小さい方の値を参照する
 */
float TouchManager::calcShift(float v1, float v2)
{
    if ((v1 > 0) != (v2 > 0)) return 0;

    float fugou = v1 > 0 ? 1 : -1;
    float a1 = abs(v1);
    float a2 = abs(v2);
    return fugou * ((a1 < a2) ? a1 : a2);
}