/**
 * Copyright (C) 2022, Protein Bioinformatics Research Group, RCNS
 *
 * Licensed under CC BY-NC 4.0, see LICENSE file for more info.
 *
 * @author Gabor Tusnady <tusnady.gabor@ttk.hu>
 * @author Csongor Gerdan <gerdan.csongor@ttk.hu>
 */

import { PluginUIContext } from 'molstar/lib/mol-plugin-ui/context';
import { Quat, Vec3 } from 'molstar/lib/mol-math/linear-algebra';
import { PluginCommands } from 'molstar/lib/mol-plugin/commands';
import { Camera } from 'molstar/lib/mol-canvas3d/camera';
import { DebugUtil } from './debug-utils';

let initialSnapshot: Camera.Snapshot;

export function storeCameraSnapshot(plugin: PluginUIContext): void {
    if (!initialSnapshot) {
        initialSnapshot = plugin.canvas3d!.camera.getSnapshot();
        DebugUtil.log('initialSnapshot stored:', initialSnapshot);
    }
}

export function loadInitialSnapshot(plugin: PluginUIContext): void {
    if (!initialSnapshot) {
        DebugUtil.log('initialSnapshot is undefined');
    } else {
        DebugUtil.log('Loading initial snapshot:', initialSnapshot);
        PluginCommands.Camera.Reset(plugin, { snapshot: initialSnapshot });
    }
}

export async function rotateCamera(plugin: PluginUIContext) {
    function rot90q(v: Vec3, axis: Vec3 = Vec3.create(1, 0, 0)): Vec3 {
        const q = Quat.setAxisAngle(Quat(), axis, -Math.PI/2);
        return Vec3.transformQuat(Vec3(), v, q);
    }
    function sub(v: Vec3, u: Vec3): Vec3 {
        return Vec3.sub(Vec3(), v, u);
    }
    function add(v: Vec3, u: Vec3): Vec3 {
        return Vec3.add(Vec3(), v, u);
    }

    if (!plugin.canvas3d) {
        return;
    }

    const cam = plugin.canvas3d!.camera;
    const snapshot = cam.getSnapshot();
    const newSnapshot = {
        ...snapshot,
        // target + rotateBy90(postition - target)
        position: add(snapshot.target, rot90q(sub(snapshot.position, snapshot.target))),
        target: snapshot.target,
        up: Vec3.negUnitZ
    };
    const duration = 100;
    PluginCommands.Camera.Reset(plugin, { snapshot: newSnapshot, durationMs: duration }).then(() => {
        setTimeout(()=> {
            requestAnimationFrame(() => plugin.canvas3d?.requestCameraReset());
        }, duration + 50); // The 2nd reset needs some delay
    });

}