import * as kiwi from '@lume/kiwi'
import Attribute from './Attribute.js'

/**
 * A SubView is automatically generated when constraints are added to a View.
 *
 * @namespace SubView
 */
class SubView {
	declare _name
	declare _type
	declare _solver
	declare _attr
	declare _intrinsicWidth: number
	declare _intrinsicHeight: number

	constructor(options) {
		this._name = options.name
		this._type = options.type
		this._solver = options.solver
		this._attr = {}
		if (!options.name) {
			this._attr[Attribute.LEFT] = new kiwi.Variable()
			this._solver.addConstraint(new kiwi.Constraint(this._attr[Attribute.LEFT], kiwi.Operator.Eq, 0))
			this._attr[Attribute.TOP] = new kiwi.Variable()
			this._solver.addConstraint(new kiwi.Constraint(this._attr[Attribute.TOP], kiwi.Operator.Eq, 0))
			this._attr[Attribute.ZINDEX] = new kiwi.Variable()
			this._solver.addConstraint(new kiwi.Constraint(this._attr[Attribute.ZINDEX], kiwi.Operator.Eq, 0))
		}
	}
	toJSON() {
		return {
			name: this.name,
			left: this.left,
			top: this.top,
			width: this.width,
			height: this.height,
		}
	}
	toString() {
		JSON.stringify(this.toJSON(), undefined, 2)
	}

	/**
	 * Name of the sub-view.
	 * @readonly
	 * @type {String}
	 */
	get name() {
		return this._name
	}

	/**
	 * Left value (`Attribute.LEFT`).
	 * @readonly
	 * @type {Number}
	 */
	get left() {
		return this._getAttrValue(Attribute.LEFT)
	}

	/**
	 * Right value (`Attribute.RIGHT`).
	 * @readonly
	 * @type {Number}
	 */
	get right() {
		return this._getAttrValue(Attribute.RIGHT)
	}

	/**
	 * Width value (`Attribute.WIDTH`).
	 * @type {Number}
	 */
	get width() {
		return this._getAttrValue(Attribute.WIDTH)
	}

	/**
	 * Height value (`Attribute.HEIGHT`).
	 * @readonly
	 * @type {Number}
	 */
	get height() {
		return this._getAttrValue(Attribute.HEIGHT)
	}

	/**
	 * Intrinsic width of the sub-view.
	 *
	 * Use this property to explicitely set the width of the sub-view, e.g.:
	 * ```javascript
	 * var view = new AutoLayout.View(AutoLayout.VisualFormat.parse('|[child1][child2]|'), {
	 *   width: 500
	 * });
	 * view.subViews.child1.intrinsicWidth = 100;
	 * console.log('child2 width: ' + view.subViews.child2.width); // 400
	 * ```
	 *
	 * @type {Number}
	 */
	get intrinsicWidth(): number {
		return this._intrinsicWidth
	}
	set intrinsicWidth(value: number) {
		if (value !== undefined && value !== this._intrinsicWidth) {
			const attr = this._getAttr(Attribute.WIDTH)
			if (this._intrinsicWidth === undefined) {
				this._solver.addEditVariable(attr, kiwi.Strength.create(this._name ? 998 : 999, 1000, 1000))
			}
			this._intrinsicWidth = value
			this._solver.suggestValue(attr, value)
			this._solver.updateVariables()
		}
	}

	/**
	 * Intrinsic height of the sub-view.
	 *
	 * See `intrinsicWidth`.
	 *
	 * @type {Number}
	 */
	get intrinsicHeight(): number {
		return this._intrinsicHeight
	}
	set intrinsicHeight(value: number) {
		if (value !== undefined && value !== this._intrinsicHeight) {
			const attr = this._getAttr(Attribute.HEIGHT)
			if (this._intrinsicHeight === undefined) {
				this._solver.addEditVariable(attr, kiwi.Strength.create(this._name ? 998 : 999, 1000, 1000))
			}
			this._intrinsicHeight = value
			this._solver.suggestValue(attr, value)
			this._solver.updateVariables()
		}
	}

	/**
	 * Top value (`Attribute.TOP`).
	 * @readonly
	 * @type {Number}
	 */
	get top() {
		return this._getAttrValue(Attribute.TOP)
	}

	/**
	 * Bottom value (`Attribute.BOTTOM`).
	 * @readonly
	 * @type {Number}
	 */
	get bottom() {
		return this._getAttrValue(Attribute.BOTTOM)
	}

	/**
	 * Horizontal center (`Attribute.CENTERX`).
	 * @readonly
	 * @type {Number}
	 */
	get centerX() {
		return this._getAttrValue(Attribute.CENTERX)
	}

	/**
	 * Vertical center (`Attribute.CENTERY`).
	 * @readonly
	 * @type {Number}
	 */
	get centerY() {
		return this._getAttrValue(Attribute.CENTERY)
	}

	/**
	 * Z-index (`Attribute.ZINDEX`).
	 * @readonly
	 * @type {Number}
	 */
	get zIndex() {
		return this._getAttrValue(Attribute.ZINDEX)
	}

	/**
	 * Returns the type of the sub-view.
	 * @readonly
	 * @type {String}
	 */
	get type() {
		return this._type
	}

	/**
	 * Gets the value of one of the attributes.
	 *
	 * @param {String|Attribute} attr Attribute name (e.g. 'right', 'centerY', Attribute.TOP).
	 * @return {Number} value or `undefined`
	 */
	getValue(attr) {
		return this._attr[attr] ? this._attr[attr].value() : undefined
	}

	/**
	 * @private
	 */
	_getAttr(attr) {
		if (this._attr[attr]) {
			return this._attr[attr]
		}
		this._attr[attr] = new kiwi.Variable()
		switch (attr) {
			case Attribute.RIGHT:
				this._getAttr(Attribute.LEFT)
				this._getAttr(Attribute.WIDTH)
				this._solver.addConstraint(
					new kiwi.Constraint(
						this._attr[attr],
						kiwi.Operator.Eq,
						this._attr[Attribute.LEFT].plus(this._attr[Attribute.WIDTH]),
					),
				)
				break
			case Attribute.BOTTOM:
				this._getAttr(Attribute.TOP)
				this._getAttr(Attribute.HEIGHT)
				this._solver.addConstraint(
					new kiwi.Constraint(
						this._attr[attr],
						kiwi.Operator.Eq,
						this._attr[Attribute.TOP].plus(this._attr[Attribute.HEIGHT]),
					),
				)
				break
			case Attribute.CENTERX:
				this._getAttr(Attribute.LEFT)
				this._getAttr(Attribute.WIDTH)
				this._solver.addConstraint(
					new kiwi.Constraint(
						this._attr[attr],
						kiwi.Operator.Eq,
						this._attr[Attribute.LEFT].plus(this._attr[Attribute.WIDTH].divide(2)),
					),
				)
				break
			case Attribute.CENTERY:
				this._getAttr(Attribute.TOP)
				this._getAttr(Attribute.HEIGHT)
				this._solver.addConstraint(
					new kiwi.Constraint(
						this._attr[attr],
						kiwi.Operator.Eq,
						this._attr[Attribute.TOP].plus(this._attr[Attribute.HEIGHT].divide(2)),
					),
				)
				break
		}
		this._solver.updateVariables()
		return this._attr[attr]
	}

	/**
	 * @private
	 */
	_getAttrValue(attr) {
		return this._getAttr(attr).value()
	}
}

export default SubView