/*
 * Tree.js
 *
 * @author realor
 */

class Tree {
    constructor(element) {
        this.rootsElem = document.createElement('ul')
        element.appendChild(this.rootsElem)
        this.rootsElem.className = 'tree'
        this.roots = []
    }

    addNode(object, action, className) {
        const treeNode = new TreeNode(this, null, object, action, className)
        this.roots.push(treeNode)
        this.rootsElem.appendChild(treeNode.itemElem)

        return treeNode
    }

    getNodeLabel(value) {
        return value
    }

    clear() {
        this.rootsElem.innerHTML = ''
        this.roots = []
    }
}

class TreeNode {
    constructor(tree, parentTreeNode, value, action, className) {
        this.tree = tree
        this.parent = parentTreeNode
        this._value = value
        this.children = []
        this.itemElem = document.createElement('li')
        this.linkElem = document.createElement('a')
        this.linkElem.href = '#'
        this.itemElem.appendChild(this.linkElem)
        this.updateLabel()

        if (action) {
            this.linkElem.addEventListener('click', action)
        }
        this.childrenElem = null
        this.buttonElem = null
        if (className) this.itemElem.className = className
    }

    addNode(value, action, className) {
        if (this.childrenElem === null) {
            this.itemElem.innerHTML = ''
            this.itemElem.classList.add('collapsed')
            this.buttonElem = document.createElement('button')
            this.buttonElem.addEventListener('click', () => this.toggle())
            this.itemElem.appendChild(this.buttonElem)
            this.itemElem.appendChild(this.linkElem)
            this.childrenElem = document.createElement('ul')
            this.itemElem.appendChild(this.childrenElem)
        } else {
            this.buttonElem.style.display = ''
        }

        const treeNode = new TreeNode(this.tree, this, value, action, className)
        this.childrenElem.appendChild(treeNode.itemElem)
        this.children.push(treeNode)

        return treeNode
    }

    remove() {
        if (this.parent) {
            let index = this.parent.children.indexOf(this)
            if (index > -1) {
                this.parent.children.splice(index, 1)
                this.parent.childrenElem.removeChild(this.itemElem)

                if (this.parent.children.length === 0) {
                    this.parent.buttonElem.style.display = 'none'
                }
            }
        } // remove from tree.roots
        else {
            let index = this.tree.roots.indexOf(this)
            if (index > -1) {
                this.tree.roots.splice(index, 1)
                this.tree.rootsElem.removeChild(this.itemElem)
            }
        }
    }

    set value(value) {
        this._value = value
        this.updateLabel()
    }

    get value() {
        return this._value
    }

    addClass(className) {
        this.linkElem.classList.add(className)
    }

    removeClass(className) {
        this.linkElem.classList.remove(className)
    }

    updateLabel() {
        this.linkElem.innerHTML = this.tree.getNodeLabel(this._value)
    }

    isExpanded() {
        return this.itemElem.classList.contains('expanded')
    }

    isCollapsed() {
        return this.itemElem.classList.contains('collapsed')
    }

    toggle() {
        if (this.isExpanded()) {
            this.collapse()
        } else {
            this.expand()
        }
    }

    expand(levels = 1) {
        if (levels > 0) {
            this.itemElem.classList.remove('collapsed')
            this.itemElem.classList.add('expanded')
            levels--
            if (levels > 0) {
                for (let i = 0; i < this.children.length; i++) {
                    this.children[i].expand(levels)
                }
            }
        }
    }

    collapse(levels = 1) {
        if (levels > 0) {
            this.itemElem.classList.remove('expanded')
            this.itemElem.classList.add('collapsed')
            levels--
            if (levels > 0) {
                for (let i = 0; i < this.children.length; i++) {
                    this.children[i].collapse(levels)
                }
            }
        }
    }

    expandAncestors(makeVisible = false) {
        let curr = this.parent
        while (curr) {
            curr.expand()
            curr = curr.parent
        }
        if (makeVisible) {
            this.linkElem.scrollIntoView({ block: 'center', inline: 'nearest' })
        }
    }

    clear() {
        if (this.childrenElem) {
            this.childrenElem.innerHTML = ''
            this.buttonElem.style.display = 'none'
        }
        this.children = []
    }
}

export { Tree }