/**
 * DocFast — Official Node.js SDK
 * https://docfast.dev
 */

export interface PdfMargin {
  top?: string;
  bottom?: string;
  left?: string;
  right?: string;
}

export interface HeaderFooter {
  content?: string;
  height?: string;
}

export interface PdfOptions {
  format?: 'A4' | 'Letter' | 'Legal' | 'A3' | 'A5' | 'Tabloid';
  landscape?: boolean;
  margin?: PdfMargin;
  header?: HeaderFooter;
  footer?: HeaderFooter;
  scale?: number;
  printBackground?: boolean;
}

export interface Template {
  id: string;
  name: string;
  description?: string;
}

export interface DocFastOptions {
  baseUrl?: string;
}

export class DocFastError extends Error {
  readonly status: number;
  readonly code?: string;

  constructor(message: string, status: number, code?: string) {
    super(message);
    this.name = 'DocFastError';
    this.status = status;
    this.code = code;
  }
}

export class DocFast {
  private readonly apiKey: string;
  private readonly baseUrl: string;

  constructor(apiKey: string, options?: DocFastOptions) {
    if (!apiKey) throw new Error('API key is required');
    this.apiKey = apiKey;
    this.baseUrl = options?.baseUrl?.replace(/\/+$/, '') ?? 'https://docfast.dev';
  }

  private async request(path: string, body: Record<string, unknown>): Promise<Buffer> {
    const res = await fetch(`${this.baseUrl}${path}`, {
      method: 'POST',
      headers: {
        'Authorization': `Bearer ${this.apiKey}`,
        'Content-Type': 'application/json',
      },
      body: JSON.stringify(body),
    });

    if (!res.ok) {
      let message = `HTTP ${res.status}`;
      let code: string | undefined;
      try {
        const err = await res.json() as { error?: string; code?: string };
        if (err.error) message = err.error;
        code = err.code;
      } catch {}
      throw new DocFastError(message, res.status, code);
    }

    const arrayBuffer = await res.arrayBuffer();
    return Buffer.from(arrayBuffer);
  }

  private async requestJson<T>(method: string, path: string): Promise<T> {
    const res = await fetch(`${this.baseUrl}${path}`, {
      method,
      headers: { 'Authorization': `Bearer ${this.apiKey}` },
    });

    if (!res.ok) {
      let message = `HTTP ${res.status}`;
      try {
        const err = await res.json() as { error?: string };
        if (err.error) message = err.error;
      } catch {}
      throw new DocFastError(message, res.status);
    }

    return res.json() as Promise<T>;
  }

  /** Convert HTML to PDF */
  async html(html: string, options?: PdfOptions): Promise<Buffer> {
    return this.request('/v1/convert/html', { html, options });
  }

  /** Convert Markdown to PDF */
  async markdown(markdown: string, options?: PdfOptions): Promise<Buffer> {
    return this.request('/v1/convert/markdown', { markdown, options });
  }

  /** Convert a URL to PDF */
  async url(url: string, options?: PdfOptions): Promise<Buffer> {
    return this.request('/v1/convert/url', { url, options });
  }

  /** List available templates */
  async templates(): Promise<Template[]> {
    return this.requestJson<Template[]>('GET', '/v1/templates');
  }

  /** Render a template to PDF */
  async renderTemplate(id: string, data: Record<string, unknown>, options?: PdfOptions): Promise<Buffer> {
    return this.request(`/v1/templates/${encodeURIComponent(id)}/render`, { data, options });
  }
}

export default DocFast;