import {
    _decorator, Camera, Component, EventMouse, EventTouch, Input, input, sys, Vec2, view,
} from 'cc';
import { CAMERA_ORTHO_HALF, DESIGN_WIDTH } from '../core/GridConstants';
import { getEmbeddedOrthoHalf } from '../core/EmbeddedView';

const { ccclass } = _decorator;

/** 与 UIMain 相同：165×165 按钮 + 右侧 20px 边距，按 2560 设计宽缩到 960 */
const HUD_BTN = Math.round(165 * DESIGN_WIDTH / 2560);
const HUD_PAD_RIGHT = Math.round(20 * DESIGN_WIDTH / 2560);
const HUD_RIGHT_SLACK = 8;

function markMapViewDirty(): void {
    (globalThis as { __tfrhPreserveMapView?: boolean }).__tfrhPreserveMapView = true;
}

function clearMapViewDirty(): void {
    (globalThis as { __tfrhPreserveMapView?: boolean }).__tfrhPreserveMapView = false;
}

/** 对齐 Unity ViewController：Orthographic 缩放与拖拽 */
@ccclass('ViewController')
export class ViewController extends Component {
    static instance: ViewController | null = null;

    /** Unity zoomSpeed=2 → 世界半高步进 200 */
    zoomSpeed = 200;
    /** Unity minZoom=3, maxZoom=10（×100 世界单位） */
    minOrtho = 300;
    maxOrtho = 1000;

    private camera: Camera | null = null;
    private dragOrigin = new Vec2();
    private readonly uiLoc = new Vec2();
    private dragging = false;

    onLoad() {
        if (ViewController.instance && ViewController.instance !== this) {
            this.destroy();
            return;
        }
        ViewController.instance = this;
        this.camera = this.getComponent(Camera);
        if (this.camera && this.camera.orthoHeight <= 0) {
            this.camera.orthoHeight = CAMERA_ORTHO_HALF;
        }
        input.on(Input.EventType.TOUCH_START, this.onTouchStart, this);
        input.on(Input.EventType.TOUCH_MOVE, this.onTouchMove, this);
        input.on(Input.EventType.TOUCH_END, this.onTouchEnd, this);
        input.on(Input.EventType.TOUCH_CANCEL, this.onTouchEnd, this);
        input.on(Input.EventType.MOUSE_DOWN, this.onMouseDown, this);
        input.on(Input.EventType.MOUSE_MOVE, this.onMouseMove, this);
        input.on(Input.EventType.MOUSE_UP, this.onMouseUp, this);
    }

    onDestroy() {
        if (ViewController.instance === this) ViewController.instance = null;
        input.off(Input.EventType.TOUCH_START, this.onTouchStart, this);
        input.off(Input.EventType.TOUCH_MOVE, this.onTouchMove, this);
        input.off(Input.EventType.TOUCH_END, this.onTouchEnd, this);
        input.off(Input.EventType.TOUCH_CANCEL, this.onTouchEnd, this);
        input.off(Input.EventType.MOUSE_DOWN, this.onMouseDown, this);
        input.off(Input.EventType.MOUSE_MOVE, this.onMouseMove, this);
        input.off(Input.EventType.MOUSE_UP, this.onMouseUp, this);
    }

    zoomIn() {
        const cam = this.camera;
        if (!cam || cam.orthoHeight <= this.minOrtho) return;
        cam.orthoHeight = Math.max(this.minOrtho, cam.orthoHeight - this.zoomSpeed);
        markMapViewDirty();
    }

    zoomOut() {
        const cam = this.camera;
        if (!cam || cam.orthoHeight >= this.maxOrtho) return;
        cam.orthoHeight = Math.min(this.maxOrtho, cam.orthoHeight + this.zoomSpeed);
        markMapViewDirty();
    }

    resetZoom() {
        const cam = this.camera;
        if (!cam) return;
        cam.orthoHeight = getEmbeddedOrthoHalf();
        cam.node.setPosition(0, 0, cam.node.position.z);
        clearMapViewDirty();
    }

    private usingMouseInput(): boolean {
        return !sys.isMobile && sys.hasFeature(sys.Feature.EVENT_MOUSE);
    }

    private onTouchStart(e: EventTouch) {
        // 桌面端鼠标会同时模拟 touch，只走 MOUSE_* 以免双倍位移、并过滤非左键
        if (this.usingMouseInput()) return;
        e.getUILocation(this.uiLoc);
        if (this.isPointerOnUI(this.uiLoc)) return;
        this.dragging = true;
        this.dragOrigin.set(this.uiLoc);
    }

    private onTouchEnd() {
        if (this.usingMouseInput()) return;
        this.dragging = false;
    }

    private onTouchMove(e: EventTouch) {
        if (this.usingMouseInput() || !this.dragging) return;
        e.getUILocation(this.uiLoc);
        this.applyDrag(this.uiLoc);
        this.dragOrigin.set(this.uiLoc);
    }

    private onMouseDown(e: EventMouse) {
        if (e.getButton() !== EventMouse.BUTTON_LEFT) return;
        e.getUILocation(this.uiLoc);
        if (this.isPointerOnUI(this.uiLoc)) return;
        this.dragging = true;
        this.dragOrigin.set(this.uiLoc);
    }

    private onMouseUp() {
        this.dragging = false;
    }

    private onMouseMove(e: EventMouse) {
        if (!this.dragging) return;
        e.getUILocation(this.uiLoc);
        this.applyDrag(this.uiLoc);
        this.dragOrigin.set(this.uiLoc);
    }

    private applyDrag(cur: Vec2) {
        if (!this.camera) return;
        const dx = cur.x - this.dragOrigin.x;
        const dy = cur.y - this.dragOrigin.y;

        const ortho = this.camera.orthoHeight;
        const { width, height } = view.getVisibleSize();
        if (width <= 0 || height <= 0) return;
        const worldPerPixelX = (2 * ortho * (width / height)) / width;
        const worldPerPixelY = (2 * ortho) / height;

        const pos = this.camera.node.position;
        let nx = pos.x - dx * worldPerPixelX;
        let ny = pos.y - dy * worldPerPixelY;

        const limit = ortho - 20;
        if (Math.abs(nx) > limit) nx = pos.x;
        if (Math.abs(ny) > limit) ny = pos.y;

        this.camera.node.setPosition(nx, ny, pos.z);
        markMapViewDirty();
    }

    /** 仅拦截右侧 HUD 按钮列；坐标为 UI 空间（原点左下，与 visibleSize 一致） */
    private isPointerOnUI(loc: Vec2): boolean {
        const vis = view.getVisibleSize();
        const right = vis.width > 0 ? vis.width : DESIGN_WIDTH;
        return loc.x >= right - HUD_BTN - HUD_PAD_RIGHT - HUD_RIGHT_SLACK;
    }
}