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

const ALLOWED_RICH_TEXT_TAGS = ['b', 'strong', 'i', 'em', 'u', 'br', 'p', 'div', 'ul', 'ol', 'li'];
const DEFAULT_FONT_SIZE = 32;

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[^>]*)?>$/i);
    if (!match) {
      return '';
    }
    const closing = Boolean(match[1]);
    const name = String(match[2] || '').toLowerCase();
    if (!ALLOWED_RICH_TEXT_TAGS.includes(name)) {
      return '';
    }
    if (name === 'br') {
      return '<br>';
    }
    return closing ? `</${name}>` : `<${name}>`;
  });
}

async function fetchSlideById(pool, id) {
  const [slides] = await pool.query(`
    SELECT s.id, s.title, s.body, s.template_id, s.content_json, s.media_path, s.media_type, s.thumbnail_path, s.created_at, s.modified_at,
           st.name AS template_name, cs.name AS canvas_size_name, cs.width AS canvas_width, cs.height AS canvas_height
    FROM slides s
    LEFT JOIN slide_templates st ON st.id = s.template_id
    LEFT JOIN 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 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 buildTemplateContent(template, body, filesByField, existingContent) {
  const content = {};
  template.regions.forEach((region) => {
    if (region.region_type === 'image') {
      const uploaded = filesByField[`region_image_${region.id}`];
      const existing = body[`existing_region_image_${region.id}`];
      content[region.region_key] = {
        type: 'image',
        value: uploaded ? `/media/uploads/${uploaded.filename}` : String(existing || '').trim() || ((existingContent && existingContent[region.region_key]) ? existingContent[region.region_key].value : '')
      };
    } else if (region.region_type === 'webpage') {
      const submitted = body[`region_webpage_${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 === '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_${region.id}`];
      const current = existingContent && existingContent[region.region_key] ? existingContent[region.region_key].value : '';
      content[region.region_key] = {
        type: 'html',
        value: submitted === undefined ? current : String(submitted || '')
      };
    } else if (region.region_type === 'rss') {
      const submitted = body[`region_text_${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));
      content[region.region_key] = {
        type: 'rss',
        value: submitted === undefined ? String(current.value || '') : String(submitted || ''),
        feed_id: feedId === undefined || feedId === null || feedId === '' ? (current.feed_id || null) : Number(feedId),
        item_number: 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_${region.id}`];
      const parsedItemNumber = Math.max(1, Number(itemNumber || current.item_number || 1));
      content[region.region_key] = {
        type: 'api',
        value: submitted === undefined ? String(current.value || '') : String(submitted || ''),
        source_id: sourceId === undefined || sourceId === null || sourceId === '' ? (current.source_id || null) : Number(sourceId),
        item_number: Number.isFinite(parsedItemNumber) && parsedItemNumber > 0 ? parsedItemNumber : 1,
        variable_name: 'item',
        font_family: style.font_family,
        font_size: style.font_size,
        font_color: style.font_color
      };
    } else {
      const submitted = body[`region_text_${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: 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 = String(req.body.title || '').trim();
  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) {
    return {
      title,
      body: existingSlide ? existingSlide.body : null,
      templateId: template.id,
      contentJson: JSON.stringify(buildTemplateContent(template, req.body, filesByField, existingContent)),
      mediaPath: null,
      mediaType: null
    };
  }

  return {
    title,
    body: existingSlide ? existingSlide.body : null,
    templateId: null,
    contentJson: existingSlide ? existingSlide.content_json : null,
    mediaPath: existingSlide ? existingSlide.media_path : null,
    mediaType: existingSlide ? existingSlide.media_type : null
  };
}

module.exports = {
  fetchSlideById,
  buildSlidePayload
};