import * as vscode from 'vscode';

export class Node {
    constructor(public label: string, public darkIcon: vscode.Uri | undefined = undefined, public lightIcon: vscode.Uri | undefined = undefined, public children: Node[] | undefined = undefined, public contextValue: string | undefined = undefined, public value: any | undefined = undefined) {}

    public serialize() : any {
        return {
            label: this.label,
            iconPath: (this.lightIcon&&this.darkIcon) ? {
                light: this.lightIcon?.fsPath,
                dark: this.darkIcon?.fsPath
            } : undefined,
            collapsibleState: this.children? vscode.TreeItemCollapsibleState.Collapsed : vscode.TreeItemCollapsibleState.None,
            contextValue: this.contextValue
        }
    }
}

export class Panel implements vscode.TreeDataProvider<Node> {

    private placeholder : Node[] = [];

    private _onDidChangeTreeData: vscode.EventEmitter<Node | undefined | null | void> = new vscode.EventEmitter<Node | undefined | null | void>();
    
    public readonly onDidChangeTreeData : vscode.Event<void | Node | null | undefined> | undefined;

    public set placeholderMessage(value: string) {
        this.placeholder = [new Node(value)];
    }

    constructor(public readonly name: string, public rootItems: Node[], placeholderMessage : string){
        this.placeholderMessage = placeholderMessage;
        this.onDidChangeTreeData = this._onDidChangeTreeData.event;  
        vscode.window.createTreeView(name, { treeDataProvider: this });
        this.UpdatePanel();
    }

    public UpdatePanel() : void {
        this._onDidChangeTreeData.fire();
    }

    getTreeItem(node: Node ): vscode.TreeItem | Thenable<vscode.TreeItem> {
        return node.serialize();
    }

    getChildren(node?: Node): Node[] {
        if(!node)
            if(this.rootItems.length>0)
                return this.rootItems;
            else
                return this.placeholder;
        else
            return node.children || [];
    }
}