import ejs from 'ejs';
import log4js from 'log4js';
import posthtml from 'posthtml';

import { documentTemplateModel } from '../database/schemas/management/documenttemplate.schema.js';
import '../database/schemas/management/documentsize.schema.js';
// Load configuration
import { loadConfig } from '../config.js';
import fs from 'fs';
import dayjs from 'dayjs';
import utc from 'dayjs/plugin/utc.js';
import timezone from 'dayjs/plugin/timezone.js';
import { fileURLToPath } from 'url';
import { dirname, join } from 'path';
import { getObject, listObjects } from '../database/database.js';
import { getModelByName } from '../utils.js';
import { generatePDF } from './pdffactory.js';
const __filename = fileURLToPath(import.meta.url);
const __dirname = dirname(__filename);

// Extend plugins
dayjs.extend(utc);
dayjs.extend(timezone);

const config = loadConfig();

const logger = log4js.getLogger('Template Manager');
logger.level = config.server.logLevel;

let baseTemplate;
let baseCSS;
let previewTemplate;
let renderTemplateEjs;
let contentPlaceholder;
let previewPaginationScript;

async function loadTemplates() {
  // Synchronously load files
  baseTemplate = fs.readFileSync(
    join(__dirname, '/assets/basetemplate.ejs'),
    'utf8'
  );
  baseCSS = fs.readFileSync(join(__dirname, '/assets/styles.css'), 'utf8');
  previewTemplate = fs.readFileSync(
    join(__dirname, '/assets/previewtemplate.ejs'),
    'utf8'
  );
  renderTemplateEjs = fs.readFileSync(
    join(__dirname, '/assets/rendertemplate.ejs'),
    'utf8'
  );
  contentPlaceholder = fs.readFileSync(
    join(__dirname, '/assets/contentplaceholder.ejs'),
    'utf8'
  );
  previewPaginationScript = fs.readFileSync(
    join(__dirname, '/assets/previewpagination.js'),
    'utf8'
  );
}

loadTemplates();

function getNodeStyles(attributes) {
  var styles = '';
  if (attributes?.padding) {
    styles += `padding: ${attributes.padding};`;
  }
  if (attributes?.width) {
    styles += `width: ${attributes.width};`;
  }
  if (attributes?.height) {
    styles += `height: ${attributes.height};`;
  }
  if (attributes?.maxWidth) {
    styles += `max-width: ${attributes.maxWidth};`;
  }
  if (attributes?.maxHeight) {
    styles += `max-height: ${attributes.maxHeight};`;
  }
  if (attributes?.gap && attributes?.vertical != 'true') {
    styles += `column-gap: ${attributes.gap};`;
  }
  if (attributes?.gap && attributes?.vertical == 'true') {
    styles += `row-gap: ${attributes.gap};`;
  }
  if (attributes?.justify) {
    styles += `justify-content: ${attributes.justify};`;
  }
  if (attributes?.align) {
    styles += `align-items: ${attributes.align};`;
  }
  if (attributes?.border) {
    styles += `border: ${attributes.border};`;
  }
  if (attributes?.borderRadius) {
    styles += `border-radius: ${attributes.borderRadius};`;
  }
  if (attributes?.vertical == 'true') {
    styles += `flex-direction: column;`;
  }
  if (attributes?.grow) {
    styles += `flex-grow: ${attributes.grow};`;
  }
  if (attributes?.shrink) {
    styles += `flex-shrink: ${attributes.shrink};`;
  }
  if (attributes?.color) {
    styles += `color: ${attributes.color};`;
  }
  if (attributes?.background) {
    styles += `background: ${attributes.background};`;
  }
  if (attributes?.scale) {
    styles += `transform: scale(${attributes.scale});`;
  }
  if (attributes?.textAlign) {
    styles += `text-align: ${attributes.textAlign};`;
  }
  if (attributes?.textSize) {
    styles += `font-size: ${attributes.textSize};`;
  }
  if (attributes?.wordWrap) {
    styles += `word-wrap: ${attributes.wordWrap};`;
  }
  return styles;
}

async function transformCustomElements(content) {
  const result = await posthtml([
    tree =>
      tree.match({ tag: 'Title1' }, node => ({
        ...node,
        tag: 'h1',
        attrs: { class: 'documentTitle' }
      })),
    tree =>
      tree.match({ tag: 'Title2' }, node => ({
        ...node,
        tag: 'h2',
        attrs: { class: 'documentTitle' }
      })),
    tree =>
      tree.match({ tag: 'Title3' }, node => ({
        ...node,
        tag: 'h3',
        attrs: { class: 'documentText' }
      })),
    tree =>
      tree.match({ tag: 'Title4' }, node => ({
        ...node,
        tag: 'h4',
        attrs: { class: 'documentText' }
      })),
    tree =>
      tree.match({ tag: 'Text' }, node => ({
        ...node,
        tag: 'p',
        attrs: { class: 'documentText', style: getNodeStyles(node.attrs) }
      })),
    tree =>
      tree.match({ tag: 'Bold' }, node => ({
        ...node,
        tag: 'strong',
        attrs: {
          style: 'font-weight: bold;',
          class: 'documentBoldText',
          style: getNodeStyles(node.attrs)
        }
      })),
    tree =>
      tree.match({ tag: 'Barcode' }, node => {
        return {
          tag: 'div',
          content: [
            {
              tag: 'svg',
              attrs: {
                class: 'documentBarcode',
                'jsbarcode-displayValue': 'false',
                'jsbarcode-value': node.content[0],
                'jsbarcode-format': node.attrs.format,
                'jsbarcode-width': node.attrs.barcodeWidth,
                'jsbarcode-margin': 0
              }
            }
          ],
          attrs: {
            class: 'documentBarcodeContainer',
            style: getNodeStyles(node.attrs)
          }
        };
      }),
    tree =>
      tree.match({ tag: 'Container' }, node => ({
        ...node,
        tag: 'div',
        attrs: {
          class: 'documentContainer',
          style: getNodeStyles(node.attrs)
        }
      })),
    tree =>
      tree.match({ tag: 'Flex' }, node => {
        return {
          ...node,
          tag: 'div',
          attrs: {
            class: 'documentFlex',
            style: getNodeStyles(node.attrs)
          }
        };
      }),
    tree =>
      tree.match({ tag: 'Divider' }, node => {
        return {
          ...node,
          tag: 'hr',
          attrs: {
            class: 'documentDivider',
            style: getNodeStyles(node.attrs)
          }
        };
      }),
    tree =>
      tree.match({ tag: 'ProgressBar' }, node => {
        return {
          ...node,
          tag: 'div',
          attrs: {
            class: 'documentProgressBar',
            style: getNodeStyles(node.attrs)
          },
          content: [
            {
              tag: 'div',
              attrs: {
                class: 'documentProgressBarInner',
                style: `width: ${Math.round((node.content[0] || 0) * 100)}%`
              }
            }
          ]
        };
      }),

    tree =>
      tree.match({ tag: 'DateTime' }, node => {
        const dateTime = dayjs.utc(node.content[0]);
        return {
          content: [dateTime.format('YYYY-MM-DD hh:mm:ss')],
          tag: 'span',
          attrs: {
            class: 'documentDateTime',
            style: getNodeStyles(node.attrs)
          }
        };
      }),
    tree =>
      tree.match({ tag: 'Table' }, node => {
        return {
          ...node,
          tag: 'table',
          attrs: {
            class: 'documentTable',
            style: getNodeStyles(node.attrs)
          }
        };
      }),
    tree =>
      tree.match({ tag: 'Row' }, node => {
        const rowType = node.attrs?.type?.toLowerCase() || '';

        // Transform Col children based on the row type (header/footer/body)
        const transformCols = content => {
          if (!Array.isArray(content)) return content;
          return content.map(child => {
            if (typeof child === 'string' || child == null) {
              return child;
            }
            if (child.tag !== 'Col') {
              return child;
            }

            const baseAttrs = {
              ...child.attrs,
              style: getNodeStyles(child.attrs)
            };

            if (rowType === 'header') {
              // Header row columns become table headers
              return {
                ...child,
                tag: 'th',
                attrs: baseAttrs
              };
            }

            // Footer and body rows both use <td>; footer is distinguished by the row class
            return {
              ...child,
              tag: 'td',
              attrs: baseAttrs
            };
          });
        };

        const content = transformCols(node.content);

        if (rowType === 'header') {
          return {
            ...node,
            tag: 'tr',
            content,
            attrs: {
              class: 'documentTableRowHeader',
              style: getNodeStyles(node.attrs)
            }
          };
        }

        if (rowType === 'footer') {
          return {
            ...node,
            tag: 'tr',
            content,
            attrs: {
              class: 'documentTableRowFooter',
              style: getNodeStyles(node.attrs)
            }
          };
        }

        return {
          ...node,
          tag: 'tr',
          content,
          attrs: {
            class: 'documentTableRow',
            style: getNodeStyles(node.attrs)
          }
        };
      })
  ]).process(content);

  return result.html;
}

export class TemplateManager {
  constructor() {
    this.fc = {
      listObjects: this.listObjects.bind(this),
      getObject: this.getObject.bind(this),
      formatDate: this.formatDate.bind(this)
    };
  }
  /**
   * Previews an EJS template by rendering it with provided data
   * @param {string} templateString - The EJS template as a string
   * @param {Object} data - Data object to pass to the template
   * @param {Object} options - EJS rendering options
   * @returns {Promise<string>} The rendered HTML string
   */
  async renderTemplate(
    id,
    content,
    data = {},
    scale = 1,
    options = {},
    preview = true
  ) {
    try {
      // Set default options for EJS rendering
      const defaultOptions = {
        async: true,
        ...options
      };
      logger.debug('Rendering template:', id);

      const documentTemplate = await getObject({
        model: documentTemplateModel,
        id,
        populate: [
          { path: 'documentSize' },
          { path: 'parent', strictPopulate: false }
        ],
        cached: true
      });

      if (documentTemplate == null) {
        return { error: 'Document template not found.' };
      }

      const documentSize = documentTemplate.documentSize;
      if (documentSize == null) {
        return { error: 'Document template size not found.' };
      }

      // Validate content parameter
      if (content == null || typeof content !== 'string') {
        return { error: 'Template content is required and must be a string.' };
      }

      // Make sure data has default undefefined values and then merge with data
      var templateData = {};
      if (documentTemplate.global == true) {
        templateData = { content: contentPlaceholder, fc: this.fc };
      } else {
        const objectType = documentTemplate?.objectType;
        const model = getModelByName(objectType);
        const defaultKeys = Object.keys(model.schema.obj);
        const defaultValues = {};
        for (const key of defaultKeys) {
          defaultValues[key] = null;
        }
        templateData = { ...defaultValues, ...data, fc: this.fc };
      }

      // Render the template
      const templateContent = await ejs.render(
        content,
        templateData,
        defaultOptions
      );

      var templateWithParentContent;

      if (documentTemplate.parent != undefined) {
        // Validate parent content
        if (
          documentTemplate.parent.content == null ||
          typeof documentTemplate.parent.content !== 'string'
        ) {
          return {
            error: 'Parent template content is required and must be a string.'
          };
        }
        templateWithParentContent = await ejs.render(
          documentTemplate.parent.content,
          { content: templateContent, fc: this.fc },
          defaultOptions
        );
      } else {
        templateWithParentContent = templateContent;
      }

      // Validate rendered content before transformation
      if (
        templateWithParentContent == null ||
        typeof templateWithParentContent !== 'string'
      ) {
        return { error: 'Failed to render template content.' };
      }

      const templateHtml = await transformCustomElements(
        templateWithParentContent
      );

      // Validate transformed HTML
      if (templateHtml == null || typeof templateHtml !== 'string') {
        return { error: 'Failed to transform template content.' };
      }

      var innerHtml = null;

      if (preview == true) {
        innerHtml = await ejs.render(
          previewTemplate,
          { content: templateHtml },
          defaultOptions
        );
      } else {
        innerHtml = await ejs.render(
          renderTemplateEjs,
          { content: templateHtml },
          defaultOptions
        );
      }

      // Validate inner HTML
      if (innerHtml == null || typeof innerHtml !== 'string') {
        return { error: 'Failed to render inner template content.' };
      }

      const baseHtml = await ejs.render(
        baseTemplate,
        {
          content: innerHtml,
          width: documentSize.width,
          height: documentSize.height,
          scale: `${scale}`,
          baseCSS: baseCSS,
          previewPaginationScript: preview ? previewPaginationScript : ''
        },
        defaultOptions
      );

      const previewObject = {
        html: baseHtml,
        width: documentSize.width,
        height: documentSize.height
      };

      return previewObject;
    } catch (error) {
      logger.warn('Error whilst previewing template:', error.message);
      return { error: error.message };
    }
  }

  /**
   * Validates if a template string is valid EJS syntax
   * @param {string} templateString - The EJS template as a string
   * @returns {boolean} True if template is valid, false otherwise
   */
  validateTemplate(templateString) {
    try {
      // Try to compile the template to check for syntax errors
      ejs.compile(templateString);
      return true;
    } catch (error) {
      return false;
    }
  }

  /**
   * Renders a template to PDF format
   * @param {string} id - The document template ID
   * @param {string} content - The template content
   * @param {Object} data - Data object to pass to the template
   * @param {number} scale - Scale factor for rendering
   * @param {Object} options - EJS rendering options
   * @returns {Promise<Object>} Object containing PDF buffer or error
   */
  async renderPDF(id, content, data = {}, options = {}) {
    try {
      logger.debug('Rendering PDF for template:', id);

      const renderedTemplate = await this.renderTemplate(
        id,
        content,
        data,
        1,
        options,
        false
      );

      if (renderedTemplate.error != undefined) {
        return { error: renderedTemplate.error };
      }
      const baseHtml = renderedTemplate.html;

      // Generate PDF using PDF factory
      const pdfBuffer = await generatePDF(baseHtml, {
        width: renderedTemplate.width,
        height: renderedTemplate.height
      });

      const pdfObject = {
        pdf: pdfBuffer
      };
      return pdfObject;
    } catch (error) {
      logger.warn('Error whilst rendering PDF:', error.message);
      return { error: error.message };
    }
  }

  async listObjects(objectType, filter = {}, populate = []) {
    const model = getModelByName(objectType);
    if (model == undefined) {
      throw new Error('Farm Control: Object type not found.');
    }
    const objects = await listObjects({
      model,
      filter,
      populate
    });
    return objects;
  }

  formatDate(date, format) {
    return dayjs(date).format(format);
  }

  async getObject(objectType, id) {
    const model = getModelByName(objectType);
    if (model == undefined) {
      throw new Error('Farm Control: Object type not found.');
    }
    const object = await getObject({ model, id, cached: true });
    return object;
  }
}