/*
 * AutoPilotController.js
 *
 * @author realor
 */

import { Controller } from './Controller.js'
import { Solid } from '../core/Solid.js'
import * as THREE from '../lib/three.module.js'

class AutoPilotController extends Controller {
    constructor(object, name) {
        super(object, name)

        this.distance = 0
        this.maxVelocity = 1
        this.maxAcceleration = 1
        this.vehiclesGroup = 'vehicles'
        this.trafficLightsGroup = 'trafficLights'

        this._animate = this.animate.bind(this)

        this._position0 = this.object.position.clone()
        this._direction = new THREE.Vector3()
        this.object.updateMatrix()
        this.object.updateMatrixWorld()

        var te = this.object.matrix.elements
        this._direction.set(te[4], te[5], te[6]).normalize() // relative to parent

        this._vector1 = new THREE.Vector3()
        this._vector2 = new THREE.Vector3(0, 1, 0) // y axis
        this.object.localToWorld(this._vector1)
        this.object.localToWorld(this._vector2)
        this._directionWorld = new THREE.Vector3()
        this._directionWorld.subVectors(this._vector2, this._vector1).normalize()

        this._velocity = 0
        this._acceleration = 0
        this._sleep = 0
    }

    onStart() {
        const application = this.application
        this._vehicles = application.scene.getObjectByName(this.vehiclesGroup)
        this._trafficLights = application.scene.getObjectByName(this.trafficLightsGroup)

        application.updateVisibility(this.object, true)

        application.addEventListener('animation', this._animate)
    }

    onStop() {
        const application = this.application
        application.removeEventListener('animation', this._animate)
    }

    animate(event) {
        if (this._sleep > 0) {
            this._sleep -= event.delta
            if (this._sleep <= 0) {
                // reset position, velocity and acceleration
                this.object.position.copy(this._position0)
                this._velocity = 0
                this._acceleration = 0
                this.object.visible = true
            }
        } else {
            var safetyDistance = 8
            var reductionDistance = 15

            var vehicle = this.getClosestVehicle()
            var trafficLight = this.getClosestTrafficLight()
            var obstacle = vehicle.distance < trafficLight.distance ? vehicle : trafficLight

            console.info(obstacle)

            if (obstacle.distance >= reductionDistance || this._velocity < obstacle.velocity) {
                if (obstacle.distance > safetyDistance) {
                    this._acceleration = parseFloat(this.maxAcceleration)
                }
            } // match velocities
            else {
                var vdelta = this._velocity - obstacle.velocity
                this._acceleration = -(vdelta * vdelta) / Math.max(obstacle.distance - safetyDistance, 0.01)
            }
            this._velocity += this._acceleration * event.delta

            if (this._velocity > this.maxVelocity) {
                this._velocity = parseFloat(this.maxVelocity)
            } else if (this._velocity < 0) {
                this._velocity = 0
            }

            var delta = this._velocity * event.delta
            // TODO: add v-axis vector
            this.object.position.x += delta * this._direction.x
            this.object.position.y += delta * this._direction.y
            this.object.position.z += delta * this._direction.z

            if (this.object.position.distanceTo(this._position0) > this.distance) {
                this._sleep = Math.random() * 10
                this.object.visible = false
            }
            var changeEvent = { type: 'nodeChanged', objects: [this.object], source: this }
            this.application.notifyEventListeners('scene', changeEvent)
        }
    }

    getClosestVehicle() {
        var minDistance = 1000
        var velocity = 0
        var closestVehicle = null
        if (this._vehicles) {
            var position = new THREE.Vector3()
            this.object.localToWorld(position)
            var vehiclePosition = new THREE.Vector3()
            var vector = new THREE.Vector3()

            var children = this._vehicles.children
            for (var i = 0; i < children.length; i++) {
                var vehicle = children[i]
                if (vehicle !== this.object && vehicle.visible && vehicle instanceof Solid) {
                    vehiclePosition.set(0, 0, 0)
                    vehicle.localToWorld(vehiclePosition)
                    vector.subVectors(vehiclePosition, position)
                    var vehicleDistance = vector.length()
                    if (vehicleDistance < minDistance) {
                        var linearDistance = vector.dot(this._directionWorld)
                        if (linearDistance > 0) {
                            // is not behind
                            var margin = Math.sqrt(vehicleDistance * vehicleDistance - linearDistance * linearDistance)
                            if (margin < 2) {
                                // car width
                                closestVehicle = vehicle
                                minDistance = vehicleDistance
                                if (vehicle.controllers && vehicle.controllers[0] && vehicle.controllers[0]._velocity) {
                                    velocity = vehicle.controllers[0]._velocity
                                } else {
                                    velocity = 0
                                }
                            }
                        }
                    }
                }
            }
        }
        return { distance: minDistance, velocity: velocity, object: closestVehicle }
    }

    getClosestTrafficLight() {
        var minDistance = 1000
        var closestLight = null
        if (this._trafficLights) {
            var position = new THREE.Vector3()
            this.object.localToWorld(position)
            var lightPosition = new THREE.Vector3()
            var lightDirection = new THREE.Vector3()
            var vector = new THREE.Vector3()

            var children = this._trafficLights.children
            for (var i = 0; i < children.length; i++) {
                var light = children[i]
                if (light.userData['Dynamic'] && light.userData['Dynamic']['state'] > 1) {
                    // not green
                    lightPosition.set(0, 0, 0)
                    light.localToWorld(lightPosition)
                    vector.subVectors(lightPosition, position)
                    var lightDistance = vector.length()
                    if (lightDistance < minDistance) {
                        vector.normalize()
                        if (vector.dot(this._directionWorld) > 0.8) {
                            // light is in front of us
                            this._vector1.set(0, 0, 0)
                            this._vector2.set(0, 1, 0) // y axis
                            light.localToWorld(this._vector1)
                            light.localToWorld(this._vector2)
                            lightDirection.subVectors(this._vector2, this._vector1).normalize()
                            if (lightDirection.dot(this._directionWorld) < -0.8) {
                                // light looks at car
                                minDistance = lightDistance
                                closestLight = light
                            }
                        }
                    }
                }
            }
        }
        return { distance: minDistance, velocity: 0, object: closestLight }
    }
}

Controller.addClass(AutoPilotController)

export { AutoPilotController }