// post_feed.js — LinkedIn Feed Smart Comment Generator
// Operates ONLY on linkedin.com/feed pages — fully independent from content.js

(function () {
  'use strict';

  const BUTTON_CLASS = 'lja-comment-btn';
  const BOX_CLASS = 'lja-comment-box';

  // ─── Utility: get stored settings ────────────────────────────────────────
  function getSettings() {
    return new Promise(resolve => {
      if (!chrome || !chrome.storage) {
        resolve({});
        return;
      }
      chrome.storage.sync.get(['apiKey', 'language'], (syncData) => {
        if (syncData && syncData.apiKey) {
          resolve(syncData);
        } else {
          chrome.storage.local.get(['apiKey', 'language'], (localData) => {
            resolve(localData || {});
          });
        }
      });
    });
  }

  // ─── Extract post text from a feed item ──────────────────────────────────
  function extractPostText(postEl) {
    const selectors = [
      '[data-testid="expandable-text-box"]', // New LinkedIn UI
      '.feed-shared-update-v2__description .break-words span[dir]',
      '.feed-shared-text-view span[dir]',
      '.update-components-text span[dir]',
      '.feed-shared-update-v2__description',
      '.feed-shared-text',
    ];
    for (const sel of selectors) {
      const el = postEl.querySelector(sel);
      if (el) {
        // Strip out the "... more" text if it exists
        const text = el.textContent.replace(/…\s*more/gi, '').trim();
        if (text.length > 20) return text;
      }
    }
    return null;
  }

  // ─── Find the action bar in a post ───────────────────────────────────────
  function findActionBar(postEl) {
    const selectors = [
      '.feed-shared-social-action-bar',
      '.social-actions-bar',
      '[data-urn] .feed-shared-social-action-bar',
    ];
    for (const sel of selectors) {
      const el = postEl.querySelector(sel);
      if (el) return el;
    }
    
    // New UI fallback: find the comment button SVG and get its parent container
    const commentSvg = postEl.querySelector('svg#comment-small, svg[data-test-icon="comment-small"]');
    if (commentSvg) {
      const btn = commentSvg.closest('button');
      if (btn && btn.parentNode) {
        return btn.parentNode; // This is the action bar container
      }
    }
    return null;
  }

  // ─── Find comment input field ─────────────────────────────────────────────
  function findCommentInput(postEl) {
    const selectors = [
      '.comments-comment-box__form-container .ql-editor',
      '.comments-comment-texteditor .ql-editor',
      '.ql-editor[contenteditable="true"]',
      '[contenteditable="true"][role="textbox"]',
      'div[contenteditable="true"]'
    ];
    for (const sel of selectors) {
      const el = postEl.querySelector(sel);
      if (el) return el;
    }
    return null;
  }

  // ─── Fill comment input (handles LinkedIn's Quill editor) ────────────────
  function fillCommentInput(inputEl, text) {
    inputEl.focus();
    inputEl.innerHTML = '';
    document.execCommand('insertText', false, text);
    inputEl.dispatchEvent(new InputEvent('input', { bubbles: true, data: text }));
    inputEl.dispatchEvent(new Event('change', { bubbles: true }));
  }

  // ─── Create the comment suggestion box ───────────────────────────────────
  function createCommentBox(postEl, commentText) {
    const existing = postEl.querySelector('.' + BOX_CLASS);
    if (existing) existing.remove();

    const isRTL = /[\u0600-\u06FF]/.test(commentText);

    const box = document.createElement('div');
    box.className = BOX_CLASS;
    box.innerHTML = `
      <div class="lja-cb-header">
        <span class="lja-cb-icon">🤖</span>
        <span class="lja-cb-title">Smart Comment</span>
        <button class="lja-cb-close" title="Close">✕</button>
      </div>
      <textarea
        class="lja-cb-text"
        dir="${isRTL ? 'rtl' : 'ltr'}"
        style="text-align: ${isRTL ? 'right' : 'left'}"
      >${commentText}</textarea>
      <div class="lja-cb-actions">
        <button class="lja-cb-copy">📋 Copy</button>
        <button class="lja-cb-paste">✅ Paste into Comment</button>
        <button class="lja-cb-regen">🔄 Regenerate</button>
      </div>
    `;

    box.querySelector('.lja-cb-close').addEventListener('click', () => box.remove());

    box.querySelector('.lja-cb-copy').addEventListener('click', function () {
      const text = box.querySelector('.lja-cb-text').value;
      navigator.clipboard.writeText(text).then(() => {
        this.textContent = '✅ Copied!';
        setTimeout(() => { this.textContent = '📋 Copy'; }, 1500);
      });
    });

    box.querySelector('.lja-cb-paste').addEventListener('click', function () {
      const text = box.querySelector('.lja-cb-text').value;

      const commentTrigger = postEl.querySelector(
        '.comment-button, [aria-label*="comment" i], [data-control-name="comment"], svg#comment-small'
      );
      let btnToClick = commentTrigger;
      if (btnToClick && btnToClick.tagName.toLowerCase() === 'svg') {
         btnToClick = btnToClick.closest('button') || btnToClick;
      }
      if (btnToClick) btnToClick.click();

      setTimeout(() => {
        const inputEl = findCommentInput(postEl);
        if (inputEl) {
          fillCommentInput(inputEl, text);
          this.textContent = '✅ Done!';
          setTimeout(() => { this.textContent = '✅ Paste into Comment'; }, 1500);
        } else {
          navigator.clipboard.writeText(text);
          this.textContent = '📋 Copied! Paste manually';
        }
      }, 500);
    });

    box.querySelector('.lja-cb-regen').addEventListener('click', async function () {
      box.remove();
      await generateComment(postEl);
    });

    const actionBar = findActionBar(postEl);
    if (actionBar) {
      actionBar.parentNode.insertBefore(box, actionBar.nextSibling);
    } else {
      postEl.appendChild(box);
    }
  }

  // ─── Core: call server and generate comment ───────────────────────────────
  async function generateComment(postEl) {
    const settings = await getSettings();
    if (!settings || !settings.apiKey) {
      alert('Please set your Gemini API key in the extension popup first.\n(Debug: Key not found in storage)');
      return;
    }

    const postText = extractPostText(postEl);
    if (!postText) {
      alert('Could not read post text. The post might be an image or video.');
      return;
    }

    const btn = postEl.querySelector('.' + BUTTON_CLASS);
    if (btn) {
      btn.disabled = true;
      btn.innerHTML = '<span class="lja-spinner"></span> Thinking...';
    }

    try {
      const response = await chrome.runtime.sendMessage({
        type: 'GEMINI_REQUEST',
        payload: {
          apiKey: settings.apiKey,
          action: 'generateComment',
          postText: postText
        }
      });

      if (!response.success) {
        throw new Error(response.error || 'Unknown error');
      }

      const commentText = response.data.comment || response.data;
      createCommentBox(postEl, commentText);

    } catch (e) {
      console.error('[LJA Feed]', e);
      alert('Comment generation failed: ' + e.message);
    } finally {
      if (btn) {
        btn.disabled = false;
        btn.innerHTML = '💬 Smart Comment';
      }
    }
  }

  // ─── Inject button into a single post ────────────────────────────────────
  function injectButton(postEl) {
    if (postEl.querySelector('.' + BUTTON_CLASS)) return; // Already injected

    const actionBar = findActionBar(postEl);
    if (!actionBar) return;

    if (!extractPostText(postEl)) return; // Skip non-text posts silently

    const btn = document.createElement('button');
    btn.className = BUTTON_CLASS;
    btn.innerHTML = '💬 Smart Comment';
    btn.title = 'Generate an AI-powered comment for this post';

    btn.addEventListener('click', (e) => {
      e.stopPropagation();
      e.preventDefault();
      generateComment(postEl);
    });

    actionBar.appendChild(btn);
  }

  // ─── Process all posts on the page ───────────────────────────────────────
  function processAllPosts() {
    // Check both classic LinkedIn UI and the new React/hash-class UI
    const posts = document.querySelectorAll(
      '.feed-shared-update-v2, .occludable-update, [data-urn*="activity"], [role="listitem"]'
    );
    posts.forEach(injectButton);
  }

  // ─── MutationObserver: watch for new posts (infinite scroll) ─────────────
  let observerTimer;
  const observer = new MutationObserver(() => {
    // Throttle the DOM scanning to prevent heavy performance hits on React updates
    if (observerTimer) return;
    observerTimer = setTimeout(() => {
      processAllPosts();
      observerTimer = null;
    }, 500);
  });

  // ─── Initialize ──────────────────────────────────────────────────────────
  function init() {
    processAllPosts();
    observer.observe(document.body, { childList: true, subtree: true });
  }

  if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', init);
  } else {
    init();
    setTimeout(init, 2000); // Fallback for delayed SPA renders
  }
})();