// Slide data access helpers, including rich-text normalization and payload building.

const { fetchTemplateById } = require('./templates');
const { parseJsonSafe, validateMaxLength } = require('./utils');

const TITLE_MAX_LENGTH = 255;
const { buildQrCodeContent } = require('./qr-code');

const DEFAULT_FONT_SIZE = 32;

const ALLOWED_RICH_TEXT_TAGS = ['a', 'b', 'blockquote', 'br', 'code', 'div', 'em', 'figure', 'figcaption', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'hr', 'i', 'img', 'li', 'ol', 'p', 'pre', 'span', 'strong', 'sub', 'sup', 'table', 'tbody', 'td', 'th', 'thead', 'tr', 'u', 'ul'];

function sanitizeRichTextAttributes(tagName, attrText) {
  const allowedAttributes = {
    a: ['href', 'title', 'target', 'rel', 'class', 'style'],
    blockquote: ['class', 'style'],
    div: ['class', 'style'],
    figure: ['class', 'style'],
    figcaption: ['class', 'style'],
    h1: ['class', 'style'],
    h2: ['class', 'style'],
    h3: ['class', 'style'],
    h4: ['class', 'style'],
    h5: ['class', 'style'],
    h6: ['class', 'style'],
    img: ['src', 'alt', 'title', 'width', 'height', 'class', 'style', 'loading', 'decoding'],
    li: ['class', 'style'],
    ol: ['class', 'style', 'start'],
    p: ['class', 'style'],
    pre: ['class', 'style'],
    span: ['class', 'style'],
    table: ['class', 'style'],
    td: ['class', 'style', 'colspan', 'rowspan'],
    th: ['class', 'style', 'colspan', 'rowspan', 'scope'],
    tr: ['class', 'style'],
    ul: ['class', 'style']
  };
  const allowed = allowedAttributes[tagName] || [];
  if (!allowed.length) {
    return '';
  }

  const attrs = [];
  String(attrText || '').replace(/([a-zA-Z0-9:-]+)(?:\s*=\s*("([^"]*)"|'([^']*)'|([^\s"'>/=`]+)))?/g, (_full, key, _valuePart, doubleQuoted, singleQuoted, bareValue) => {
    const lowerKey = String(key || '').toLowerCase();
    if (!allowed.includes(lowerKey)) {
      return '';
    }

    const value = doubleQuoted !== undefined ? doubleQuoted : singleQuoted !== undefined ? singleQuoted : bareValue !== undefined ? bareValue : '';
    if (lowerKey === 'href' && /^(?:\s*javascript:|\s*data:)/i.test(String(value || ''))) {
      return '';
    }
    if (lowerKey === 'style' && /(?:expression\s*\(|javascript:|url\s*\()/i.test(String(value || ''))) {
      return '';
    }
    if (lowerKey === 'target') {
      const targetValue = String(value || '').trim();
      if (targetValue === '_blank') {
        attrs.push(' target="_blank"');
        if (!attrs.includes(' rel="noreferrer noopener"')) {
          attrs.push(' rel="noreferrer noopener"');
        }
        return '';
      }
    }
    attrs.push(' ' + lowerKey + '="' + String(value || '').replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;').replace(/'/g, '&#39;') + '"');
    return '';
  });

  return attrs.join('');
}

function sanitizeRichText(html) {
  let output = String(html || '');
  output = output.replace(/<script[\s\S]*?<\/script>/gi, '');
  output = output.replace(/<style[\s\S]*?<\/style>/gi, '');
  return output.replace(/<[^>]+>/g, (tag) => {
    const match = tag.match(/^<\s*(\/?)\s*([a-z0-9]+)([\s\S]*?)(\/?)>$/i);
    if (!match) {
      return '';
    }
    const closing = Boolean(match[1]);
    const name = String(match[2] || '').toLowerCase();
    const attrText = String(match[3] || '');
    if (!ALLOWED_RICH_TEXT_TAGS.includes(name)) {
      return '';
    }
    if (closing) {
      return `</${name}>`;
    }
    return `<${name}${sanitizeRichTextAttributes(name, attrText)}>`;
  });
}

function stripEditorOnlyMarkup(value) {
  return String(value || '')
    .replace(/<pre[^>]*class="[^"]*api-region-sample-preview[^"]*"[^>]*>[\s\S]*?<\/pre>/gi, '')
    .replace(/<details[^>]*class="[^"]*api-region-sample-accordion[^"]*"[^>]*>[\s\S]*?<\/details>/gi, '')
    .trim();
}

function normalizeEditorMarkup(value) {
  return String(value === undefined || value === null ? '' : value).trim();
}

async function fetchSlideById(pool, id) {
  const [slides] = await pool.query(`
    SELECT s.id, s.title, s.template_id, s.content_json, s.thumbnail_path, s.created_at, s.modified_at,
           st.name AS template_name, st.canvas_size_id, cs.name AS canvas_size_name, cs.width AS canvas_width, cs.height AS canvas_height
    FROM c_slides s
    LEFT JOIN c_templates st ON st.id = s.template_id
    LEFT JOIN c_canvas_sizes cs ON cs.id = st.canvas_size_id
    WHERE s.id = ?
  `, [id]);
  if (!slides.length) {
    return null;
  }
  const slide = slides[0];
  slide.content = parseJsonSafe(slide.content_json) || {};
  if (slide.template_id) {
    slide.template = await fetchTemplateById(pool, slide.template_id);
  }
  return slide;
}

function getFilesByField(files) {
  const map = {};
  (files || []).forEach((file) => {
    map[file.fieldname] = file;
  });
  return map;
}

function getSubmittedValue(body, key, fallback) {
  if (body && Object.prototype.hasOwnProperty.call(body, key)) {
    return String(body[key] || '').trim();
  }

  return fallback;
}

function sanitizeTextColor(value, fallback) {
  const raw = String(value || '').trim();
  if (/^#[0-9a-fA-F]{6}$/.test(raw) || /^#[0-9a-fA-F]{3}$/.test(raw)) {
    return raw;
  }
  return fallback || '#000000';
}

function sanitizeFontSize(value, fallback) {
  const raw = String(value || '').trim();
  const parsed = Math.round(Number(raw.replace(/[^0-9.]/g, '')));
  if (Number.isFinite(parsed) && parsed > 0) {
    return parsed;
  }
  return Math.max(8, Number(fallback || DEFAULT_FONT_SIZE));
}

function getTextRegionStyle(body, region, existingContent) {
  const existing = existingContent && existingContent[region.region_key] ? existingContent[region.region_key] : {};
  const fontFamily = String(body[`region_font_family_${region.id}`] || existing.font_family || region.font_family || 'Arial').trim() || 'Arial';
  const fontSize = sanitizeFontSize(body[`region_font_size_${region.id}`], existing.font_size || DEFAULT_FONT_SIZE);
  const fontColor = sanitizeTextColor(body[`region_font_color_${region.id}`] || existing.font_color || region.font_color || '#000000');
  return {
    font_family: fontFamily,
    font_size: fontSize,
    font_color: fontColor
  };
}

function getQrRegionStyle(body, region, existingContent) {
  const existing = existingContent && existingContent[region.region_key] ? existingContent[region.region_key] : {};
  const styleKeys = [
    'qr_margin',
    'qr_background_color',
    'qr_background_transparent',
    'qr_background_color_mode',
    'qr_background_gradient_type',
    'qr_background_gradient_rotation',
    'qr_background_gradient_color_1',
    'qr_background_gradient_color_2',
    'qr_dots_color',
    'qr_dots_type',
    'qr_dots_color_mode',
    'qr_dots_gradient_type',
    'qr_dots_gradient_rotation',
    'qr_dots_gradient_color_1',
    'qr_dots_gradient_color_2',
    'qr_corners_square_color',
    'qr_corners_square_type',
    'qr_corners_square_color_mode',
    'qr_corners_square_gradient_type',
    'qr_corners_square_gradient_rotation',
    'qr_corners_square_gradient_color_1',
    'qr_corners_square_gradient_color_2',
    'qr_corners_dot_color',
    'qr_corners_dot_type',
    'qr_corners_dot_color_mode',
    'qr_corners_dot_gradient_type',
    'qr_corners_dot_gradient_rotation',
    'qr_corners_dot_gradient_color_1',
    'qr_corners_dot_gradient_color_2',
    'qr_image',
    'qr_image_size',
    'qr_image_margin',
    'qr_image_hide_background_dots',
    'qr_border_radius'
  ];
  const style = {};

  styleKeys.forEach((key) => {
    const fieldNames = [`region_${key}_${region.id}`, `${key}_${region.id}`];
    let fieldName = fieldNames[0];
    let hasSubmittedValue = false;
    let submitted;

    for (let index = 0; index < fieldNames.length; index += 1) {
      const candidate = fieldNames[index];
      if (Object.prototype.hasOwnProperty.call(body || {}, candidate)) {
        fieldName = candidate;
        hasSubmittedValue = true;
        submitted = body[candidate];
        break;
      }
    }

    const value = String(submitted || '').trim();

    if (key === 'qr_background_transparent' || key === 'qr_image_hide_background_dots') {
      style[key] = hasSubmittedValue;
      return;
    }

    if (key === 'qr_background_color_mode' || key === 'qr_dots_color_mode' || key === 'qr_corners_square_color_mode' || key === 'qr_corners_dot_color_mode' || key === 'qr_background_gradient_type' || key === 'qr_dots_gradient_type' || key === 'qr_corners_square_gradient_type' || key === 'qr_corners_dot_gradient_type') {
      style[key] = value === 'none' ? 'none' : value;
      return;
    }

    if (key === 'qr_image') {
      style[key] = value;
      return;
    }

    if (submitted === undefined) {
      if (existing[key] !== undefined && existing[key] !== null && String(existing[key]).trim() !== '') {
        style[key] = existing[key];
      }
      return;
    }

    if (value !== '') {
      if (key === 'qr_margin') {
        const parsedMargin = Number(value);
        if (Number.isFinite(parsedMargin)) {
          style[key] = Math.max(0, Math.round(parsedMargin));
        }
        return;
      }

      if (key === 'qr_image_size') {
        const parsedSize = Number(value);
        if (Number.isFinite(parsedSize)) {
          style[key] = Math.max(0, Math.min(1, parsedSize));
        }
        return;
      }

      if (key === 'qr_image_margin' || key === 'qr_border_radius') {
        const parsedImageMargin = Number(value);
        if (Number.isFinite(parsedImageMargin)) {
          style[key] = Math.max(0, Math.round(parsedImageMargin));
        }
        return;
      }

      style[key] = value;
    }
  });

  return style;
}

async function getRssFeedItemCount(pool, feedId) {
  const [rows] = await pool.query(
    'SELECT COUNT(*) AS count FROM i_rss_feed_items WHERE rss_feed_id = ?',
    [feedId]
  );

  return Number(rows && rows[0] && rows[0].count) || 0;
}

async function buildTemplateContent(pool, template, body, filesByField, existingContent) {
  const content = {};
  for (const region of template.regions) {
    if (region.region_type === 'image') {
      const uploaded = filesByField[`region_image_${region.id}`];
      const existing = body[`existing_region_image_${region.id}`];
      const current = existingContent && existingContent[region.region_key] ? existingContent[region.region_key].value : '';
      content[region.region_key] = {
        type: 'image',
        value: uploaded ? `/media/uploads/${uploaded.filename}` : getSubmittedValue(body, `existing_region_image_${region.id}`, current)
      };
    } else if (region.region_type === 'video') {
      const uploaded = filesByField[`region_video_${region.id}`];
      const existing = body[`existing_region_video_${region.id}`];
      const durationValue = body[`existing_region_video_duration_${region.id}`];
      const existingDuration = existingContent && existingContent[region.region_key] ? Number(existingContent[region.region_key].duration_seconds || 0) : 0;
      const parsedDuration = Number(durationValue || existingDuration || 0);
      const normalizedDuration = Math.round(parsedDuration * 1000) / 1000;
      const current = existingContent && existingContent[region.region_key] ? existingContent[region.region_key].value : '';
      content[region.region_key] = {
        type: 'video',
        value: uploaded ? `/media/uploads/${uploaded.filename}` : getSubmittedValue(body, `existing_region_video_${region.id}`, current),
        duration_seconds: Number.isFinite(normalizedDuration) && normalizedDuration > 0 ? normalizedDuration : null
      };
    } else if (region.region_type === 'webpage') {
      const submitted = body[`region_webpage_${region.id}`];
      const current = existingContent && existingContent[region.region_key] ? existingContent[region.region_key].value : '';
      content[region.region_key] = {
        type: 'webpage',
        value: submitted === undefined ? current : String(submitted || '').trim()
      };
    } else if (region.region_type === 'qr-code') {
      const uploadedImage = filesByField[`region_qr_image_${region.id}`];
      const submitted = body[`region_qr_code_${region.id}`];
      const submittedSvg = body[`region_qr_svg_${region.id}`];
      const submittedPreview = body[`region_qr_preview_${region.id}`];
      const existingImage = body[`existing_region_qr_image_${region.id}`];
      const current = existingContent && existingContent[region.region_key] ? existingContent[region.region_key] : {};
      const nextValue = submitted === undefined ? String(current.value !== undefined ? current.value : current.qr_code || '').trim() : String(submitted || '').trim();
      const qrStyle = getQrRegionStyle(body, region, existingContent);
      delete qrStyle.qr_image;
      content[region.region_key] = {
        type: 'qr-code',
        value: nextValue,
        qr_svg: submittedSvg === undefined ? String(current.qr_svg || '').trim() : String(submittedSvg || '').trim(),
        qr_preview: submittedPreview === undefined ? String(current.qr_preview || '').trim() : String(submittedPreview || '').trim(),
        qr_image: uploadedImage ? `/media/uploads/${uploadedImage.filename}` : String(existingImage === undefined ? String(current.qr_image || '').trim() : String(existingImage || '').trim()),
        ...qrStyle
      };
    } else if (region.region_type === 'rtmp') {
      const submitted = body[`region_rtmp_${region.id}`];
      const current = existingContent && existingContent[region.region_key] ? existingContent[region.region_key] : {};
      content[region.region_key] = {
        type: 'rtmp',
        value: submitted === undefined ? String(current.value || '').trim() : String(submitted || '').trim(),
        disable_audio: Boolean(body[`region_disable_audio_${region.id}`])
      };
    } else if (region.region_type === 'html') {
      const submitted = body[`region_html_${region.id}`];
      const current = existingContent && existingContent[region.region_key] ? existingContent[region.region_key].value : '';
      content[region.region_key] = {
        type: 'html',
        value: submitted === undefined ? current : String(submitted || '')
      };
    } else if (region.region_type === 'time-date') {
      const submitted = body[`region_text_${region.id}`];
      const current = existingContent && existingContent[region.region_key] ? existingContent[region.region_key] : {};
      const timezoneValue = body[`region_timezone_${region.id}`];
      content[region.region_key] = {
        type: 'time-date',
        value: submitted === undefined ? String(current.value !== undefined ? current.value : current.text !== undefined ? current.text : '') : String(submitted || ''),
        timezone: timezoneValue === undefined || timezoneValue === null ? String(current.timezone || current.time_zone || '') : String(timezoneValue || '').trim()
      };
    } else if (region.region_type === 'timetable') {
      const current = existingContent && existingContent[region.region_key] && typeof existingContent[region.region_key] === 'object' ? existingContent[region.region_key] : {};
      const suffix = '_' + region.id;
      const generic = {};
      const submittedText = body[`region_text_${region.id}`];
      const normalizedText = submittedText === undefined ? String(current.text !== undefined ? current.text : current.value !== undefined ? current.value : '') : String(submittedText || '');

      Object.keys(body || {}).forEach((key) => {
        if (!key.startsWith('region_') || !key.endsWith(suffix)) {
          return;
        }

        const field = key.slice('region_'.length, -suffix.length);
        if (!field || field === 'type' || field === 'key' || field === 'name' || field === 'label') {
          return;
        }

        generic[field] = body[key];
      });

      if (Object.prototype.hasOwnProperty.call(generic, 'timetable_display_mode')) {
        generic.display_mode = generic.timetable_display_mode;
        delete generic.timetable_display_mode;
      }

      if (Object.prototype.hasOwnProperty.call(generic, 'timetable_max_items')) {
        generic.max_items = generic.timetable_max_items;
        delete generic.timetable_max_items;
      }

      Object.keys(current).forEach((key) => {
        if (generic[key] === undefined) {
          generic[key] = current[key];
        }
      });

      delete generic.timetable_display_mode;
      delete generic.timetable_max_items;

      generic.text = normalizedText;
      generic.value = normalizedText;
      generic.type = region.region_type;
      content[region.region_key] = generic;
    } else if (region.region_type === 'rss') {
      const submitted = body[`region_text_${region.id}`];
      const current = existingContent && existingContent[region.region_key] ? existingContent[region.region_key] : {};
      const style = getTextRegionStyle(body, region, existingContent);
      const feedId = body[`region_rss_feed_id_${region.id}`];
      const itemNumber = body[`region_rss_item_number_${region.id}`];
      const parsedItemNumber = Math.max(1, Number(itemNumber || current.item_number || 1));
      const normalizedFeedId = feedId === undefined || feedId === null || feedId === '' ? Number(current.feed_id || 0) : Number(feedId);
      const itemCount = normalizedFeedId > 0 ? Math.max(1, await getRssFeedItemCount(pool, normalizedFeedId) || 1) : 1;
      content[region.region_key] = {
        type: 'rss',
        value: stripEditorOnlyMarkup(normalizeEditorMarkup(submitted === undefined ? String(current.value || '') : String(submitted || ''))),
        feed_id: feedId === undefined || feedId === null ? (current.feed_id || null) : (feedId === '' ? null : Number(feedId)),
        item_number: Math.min(itemCount, Number.isFinite(parsedItemNumber) && parsedItemNumber > 0 ? parsedItemNumber : 1),
        variable_name: 'item',
        font_family: style.font_family,
        font_size: style.font_size,
        font_color: style.font_color
      };
    } else if (region.region_type === 'api') {
      const submitted = body[`region_text_${region.id}`];
      const current = existingContent && existingContent[region.region_key] ? existingContent[region.region_key] : {};
      const style = getTextRegionStyle(body, region, existingContent);
      const sourceId = body[`region_api_source_id_${region.id}`];
      const itemNumber = body[`region_api_item_number_${region.id}`];
      const itemsPath = body[`region_api_items_path_${region.id}`];
      const parsedItemNumber = Math.max(1, Number(itemNumber || current.item_number || 1));
      content[region.region_key] = {
        type: 'api',
        value: stripEditorOnlyMarkup(normalizeEditorMarkup(submitted === undefined ? String(current.value || '') : String(submitted || ''))),
        source_id: sourceId === undefined || sourceId === null ? (current.source_id || null) : (sourceId === '' ? null : Number(sourceId)),
        item_number: Number.isFinite(parsedItemNumber) && parsedItemNumber > 0 ? parsedItemNumber : 1,
        items_path: itemsPath === undefined || itemsPath === null ? (current.items_path === undefined || current.items_path === null ? '' : String(current.items_path)) : String(itemsPath || '').trim(),
        variable_name: 'item',
        font_family: style.font_family,
        font_size: style.font_size,
        font_color: style.font_color
      };
    } else if (region.region_type === 'weather') {
      const current = existingContent && existingContent[region.region_key] ? existingContent[region.region_key] : {};
      const locationId = body[`region_weather_location_id_${region.id}`];
      const submittedForecastMode = body[`region_weather_forecast_mode_${region.id}`];
      const forecastMode = ['current', 'hourly'].includes(submittedForecastMode) ? submittedForecastMode : 'daily';
      const style = getTextRegionStyle(body, region, existingContent);
      content[region.region_key] = {
        type: 'weather',
        value: body[`region_text_${region.id}`] !== undefined ? String(body[`region_text_${region.id}`] || '') : String(current.value || ''),
        weather_location_id: locationId === undefined || locationId === null ? (current.weather_location_id || null) : (locationId === '' ? null : Number(locationId)),
        forecast_mode: body[`region_weather_forecast_mode_${region.id}`] === undefined ? (['current', 'hourly'].includes(current.forecast_mode) ? current.forecast_mode : 'daily') : forecastMode,
        font_family: style.font_family,
        font_size: style.font_size,
        font_color: style.font_color
      };
    } else if (!['text', 'image', 'video', 'webpage', 'qr-code', 'html', 'rtmp', 'rss', 'api', 'weather'].includes(String(region.region_type || '').trim())) {
      const current = existingContent && existingContent[region.region_key] && typeof existingContent[region.region_key] === 'object' ? existingContent[region.region_key] : {};
      const suffix = '_' + region.id;
      const generic = {};

      Object.keys(body || {}).forEach((key) => {
        if (!key.startsWith('region_') || !key.endsWith(suffix)) {
          return;
        }
        const field = key.slice('region_'.length, -suffix.length);
        if (!field || field === 'type' || field === 'key' || field === 'name' || field === 'label') {
          return;
        }
        generic[field] = body[key];
      });

      Object.keys(filesByField || {}).forEach((fieldName) => {
        if (!fieldName.startsWith('region_') || !fieldName.endsWith(suffix)) {
          return;
        }
        const field = fieldName.slice('region_'.length, -suffix.length);
        if (!field) {
          return;
        }
        generic[field] = `/media/uploads/${filesByField[fieldName].filename}`;
      });

      Object.keys(current).forEach((key) => {
        if (generic[key] === undefined) {
          generic[key] = current[key];
        }
      });

      generic.type = region.region_type;
      content[region.region_key] = generic;
    } else {
      const submitted = body[`region_text_${region.id}`];
      const current = existingContent && existingContent[region.region_key] ? existingContent[region.region_key].value : '';
      const style = getTextRegionStyle(body, region, existingContent);
      content[region.region_key] = {
        type: 'text',
        value: sanitizeRichText(stripEditorOnlyMarkup(normalizeEditorMarkup(submitted === undefined ? current : String(submitted || '')))),
        font_family: style.font_family,
        font_size: style.font_size,
        font_color: style.font_color
      };
    }
  }
  return content;
}

async function buildSlidePayload(pool, req, existingSlide) {
  const title = validateMaxLength(req.body.title || '', TITLE_MAX_LENGTH, 'Slide title');
  const templateId = req.body.template_id ? Number(req.body.template_id) : null;
  const filesByField = getFilesByField(req.files || []);
  const template = templateId ? await fetchTemplateById(pool, templateId) : null;
  const existingContent = existingSlide ? parseJsonSafe(existingSlide.content_json) || {} : {};

  if (!title) {
    const error = new Error('Slide title is required.');
    error.statusCode = 400;
    throw error;
  }

  if (templateId && !template) {
    const error = new Error('Template not found.');
    error.statusCode = 400;
    throw error;
  }

  if (template) {
    const content = await buildTemplateContent(pool, template, req.body, filesByField, existingContent);
    await Promise.all(Object.keys(content).map(async function (regionKey) {
      const region = template.regions.find(function (item) {
        return String(item.region_key || '').trim() === regionKey;
      });
      if (!region || region.region_type !== 'qr-code') {
        return;
      }

      content[regionKey] = await buildQrCodeContent(content[regionKey]);
    }));

    return {
      title,
      templateId: template.id,
      contentJson: JSON.stringify(content)
    };
  }

  return {
    title,
    templateId: null,
    contentJson: existingSlide ? existingSlide.content_json : null
  };
}

module.exports = {
  fetchSlideById,
  buildSlidePayload
};