import * as plugins from './smartxml.plugins.js';

/**
 * A lightweight chainable XML builder that provides a fluent API
 * for programmatically constructing XML documents.
 */
export class XmlBuilder {
  private stack: any[] = [];
  private current: any = null;
  private rootElement: any = null;

  /**
   * Creates a new XML builder instance
   * @param input Optional: object to convert to XML, or XML string to parse
   */
  constructor(input?: any) {
    if (input) {
      if (typeof input === 'string') {
        // Parse XML string using fast-xml-parser
        const parser = new plugins.fastXmlParser.XMLParser({
          preserveOrder: true,
          ignoreAttributes: false,
        });
        this.rootElement = parser.parse(input);
        this.current = this.rootElement;
      } else if (typeof input === 'object') {
        // Accept object input
        this.rootElement = input;
        this.current = input;
      }
    }
  }

  /**
   * Static factory method for creating instances
   */
  static create(input?: any): XmlBuilder {
    return new XmlBuilder(input);
  }

  /**
   * Add an element
   * @param name Element name
   * @param attributes Optional attributes object
   */
  public ele(name: string, attributes?: Record<string, any>): this {
    if (!this.current) {
      // First element becomes root
      this.rootElement = {};
      this.current = this.rootElement;
    }

    const newElement: any = {};

    // Add attributes with @_ prefix (fast-xml-parser format)
    if (attributes) {
      for (const [key, value] of Object.entries(attributes)) {
        newElement[`@_${key}`] = value;
      }
    }

    // Check if this property already exists
    if (this.current[name]) {
      // Convert to array if not already
      if (!Array.isArray(this.current[name])) {
        this.current[name] = [this.current[name]];
      }
      this.current[name].push(newElement);
      this.stack.push(this.current);
      this.current = newElement;
    } else {
      this.current[name] = newElement;
      this.stack.push(this.current);
      this.current = newElement;
    }

    return this;
  }

  /**
   * Add text content to current element
   * @param content Text content
   */
  public txt(content: string | number): this {
    if (this.current) {
      // Check if current element already has properties
      const hasProperties = Object.keys(this.current).length > 0;
      if (hasProperties) {
        // Use #text format for mixed content
        this.current['#text'] = String(content);
      } else {
        // For simple text-only elements, we can use direct assignment
        // But to maintain consistency, we'll use #text
        this.current['#text'] = String(content);
      }
    }
    return this;
  }

  /**
   * Add attribute to current element
   * @param name Attribute name
   * @param value Attribute value
   */
  public att(name: string, value: any): this {
    if (this.current) {
      this.current[`@_${name}`] = value;
    }
    return this;
  }

  /**
   * Move up to parent element
   */
  public up(): this {
    if (this.stack.length > 0) {
      this.current = this.stack.pop();
    }
    return this;
  }

  /**
   * Get the root element (for navigation)
   */
  public root(): this {
    if (this.stack.length > 0) {
      this.current = this.stack[0];
      this.stack = [];
    }
    return this;
  }

  /**
   * Add a comment
   * @param content Comment text
   */
  public com(content: string): this {
    // Comments in fast-xml-parser format
    if (this.current) {
      if (!this.current['#comment']) {
        this.current['#comment'] = [];
      }
      if (!Array.isArray(this.current['#comment'])) {
        this.current['#comment'] = [this.current['#comment']];
      }
      this.current['#comment'].push(content);
    }
    return this;
  }

  /**
   * Serialize the XML document
   * @param options Serialization options
   */
  public end(options?: { prettyPrint?: boolean; format?: string }): string | any {
    const opts = options || {};

    if (opts.format === 'object') {
      return this.rootElement;
    }

    // Use fast-xml-parser to build XML
    const builder = new plugins.fastXmlParser.XMLBuilder({
      ignoreAttributes: false,
      attributeNamePrefix: '@_',
      format: opts.prettyPrint !== false,
      indentBy: '  ',
    });

    const xml = builder.build(this.rootElement || {});
    return '<?xml version="1.0" encoding="UTF-8"?>\n' + xml;
  }

  /**
   * Convert to string (alias for end)
   */
  public toString(): string {
    return this.end() as string;
  }
}