// Prevent double-install (if injected by manifest + programmatically)
if (window.__dewemoji_cs_installed) {
    // already installed in this page context
    // Optional: console.debug('[Dewemoji] content.js already installed');
} else {
    window.__dewemoji_cs_installed = true;
    // (keep the rest of your file below as-is)

    // Throttle to animation frame to avoid excessive work on rapid events
    function rafThrottle(fn){
      let scheduled = false;
      return function(...args){
        if (scheduled) return;
        scheduled = true;
        requestAnimationFrame(() => { scheduled = false; fn.apply(this,args); });
      };
    }

    let lastEditable = null;    // HTMLElement (input/textarea/contenteditable root)
    let lastRange = null;       // Range for contenteditable
    let lastStart = 0, lastEnd = 0;

    let lastInsertOK = null;        // true | false | null
    let lastInsertMessage = "";     // short note like "Inserted into input"
    let _insertingLock = false;

    // Find nearest contenteditable root
    function nearestEditableRoot(node) {
    let el = node instanceof Element ? node : node?.parentElement;
    while (el) {
        if (el.isContentEditable) return el;
        el = el.parentElement;
    }
    return null;
    }

    function isTextInput(el) {
    return el && (
        el.tagName === 'TEXTAREA' ||
        (el.tagName === 'INPUT' && /^(text|search|email|url|tel|password|number)?$/i.test(el.type))
    );
    }

    function captureCaret() {
    const active = document.activeElement;
    if (isTextInput(active)) {
        lastEditable = active;
        lastStart = active.selectionStart ?? active.value.length;
        lastEnd = active.selectionEnd ?? active.value.length;
        lastRange = null; // not used for inputs
        return;
    }

    const root = nearestEditableRoot(active);
    if (root) {
        lastEditable = root;
        const sel = window.getSelection();
        if (sel && sel.rangeCount > 0) {
        // clone so we can restore after panel steals focus
        lastRange = sel.getRangeAt(0).cloneRange();
        }
        return;
    }

    // Not in an editable element
    lastEditable = null;
    lastRange = null;
    }

    captureCaret();

    // Use a non-throttled handler for focusin so we snapshot *before* focus leaves to the side panel.
    document.addEventListener('focusin', captureCaret, true);

    // Throttled handlers for noisy updates
    const captureCaretThrottled = rafThrottle(captureCaret);
    document.addEventListener('keyup', captureCaretThrottled, true);
    document.addEventListener('mouseup', captureCaretThrottled, true);
    document.addEventListener('selectionchange', captureCaretThrottled, true);

    // Extra safety: when the page is about to hide (e.g., side panel opens), keep the last known caret
    document.addEventListener('visibilitychange', () => { if (document.visibilityState === 'hidden') captureCaret(); }, true);

    // Attempt to insert text at the last saved position
    function insertAtCaret(text) {
        if (!text) return false;

        // guard: ignore if a prior insert is still finishing
        if (_insertingLock) return false;
        _insertingLock = true;
        setTimeout(() => { _insertingLock = false; }, 180);

        // --- RECOVERY: if we don't have a saved target, try to rebuild from current selection
        if (!lastEditable || !document.contains(lastEditable)) {
            const sel = window.getSelection && window.getSelection();
            if (sel && sel.rangeCount > 0) {
            const root = nearestEditableRoot(sel.anchorNode);
            if (root) {
                lastEditable = root;
                lastRange = sel.getRangeAt(0).cloneRange();
            }
        }
    }

    if (!lastEditable || !document.contains(lastEditable)){
        lastInsertOK = false;
        lastInsertMessage = "No editable target";
        return false;
    };

    // Re-focus target first (side panel blurred it)
    lastEditable.focus();

    // (A) Plain inputs / textareas
    if (isTextInput(lastEditable)) {
        const el = lastEditable;
        const val = el.value ?? '';
        const start = el.selectionStart ?? lastStart ?? val.length;
        const end   = el.selectionEnd ?? lastEnd ?? start;
        el.value = val.slice(0, start) + text + val.slice(end);
        const pos = start + text.length;
        try { el.setSelectionRange(pos, pos); } catch {}
        el.dispatchEvent(new Event('input', { bubbles: true }));
        // console.log('[Dewemoji DEBUG] Inserted into input/textarea');
        // when insertion succeeds in input/textarea
        lastInsertOK = true;
        lastInsertMessage = "Inserted into input/textarea";
        return true;
    }

    // (B) contenteditable roots (Lexical/Draft/React)
    const sel = window.getSelection();
    sel.removeAllRanges();

    if (lastRange) {
        // restore exact caret
        const r = lastRange.cloneRange();
        sel.addRange(r);
    } else {
        // fallback: caret at end of root
        const r = document.createRange();
        r.selectNodeContents(lastEditable);
        r.collapse(false);
        sel.addRange(r);
    }

    // First try execCommand (still supported by many editors)
    let insertedCE = document.execCommand('insertText', false, text);
    if (!insertedCE) {
        // Manual Range insertion
        if (sel.rangeCount > 0) {
            const r = sel.getRangeAt(0);
            r.deleteContents();
            r.insertNode(document.createTextNode(text));
            // move caret to end
            r.setStart(r.endContainer, r.endOffset);
            r.collapse(true);
            sel.removeAllRanges();
            sel.addRange(r);
            insertedCE = true;
        }
    }

    try {
        lastEditable.dispatchEvent(new InputEvent('input', {
        data: text,
        inputType: 'insertText',
        bubbles: true,
        cancelable: true,
        composed: true
        }));
    } catch {
        lastEditable.dispatchEvent(new Event('input', { bubbles: true }));
    }

    captureCaret(); // refresh snapshot

    // mark success if we inserted either way
    if (insertedCE) {
    lastInsertOK = true;
    lastInsertMessage = "Inserted into contenteditable";
    return true;
    }

    // if we got here, we didn't manage to insert
    lastInsertOK = false;
    lastInsertMessage = "Insert failed in contenteditable";
    return false;
    }

    // Message bridge
    chrome.runtime.onMessage.addListener((msg, _sender, sendResponse) => {

        if (msg?.type === 'dewemoji_ping') {
        sendResponse({ ok: true });
        return;
        }
        if (msg?.type === 'dewemoji_insert') {
        const ok = insertAtCaret(msg.text);
        sendResponse({ ok });
        return;
        }
        if (msg?.type === 'dewemoji_diag') {
        // Report what we currently know
        const active = document.activeElement;
        const type =
            active && (active.tagName === 'TEXTAREA' || active.tagName === 'INPUT')
            ? active.tagName.toLowerCase()
            : (active && active.isContentEditable) ? 'contenteditable' : null;
    
        let hasRange = false;
        if (type === 'contenteditable') {
            const sel = window.getSelection();
            hasRange = !!(sel && sel.rangeCount > 0);
        } else if (type) {
            hasRange = true; // inputs/textarea use selectionStart/End
        }
    
        sendResponse({
            ok: true,
            activeType: type,           // 'input' | 'textarea' | 'contenteditable' | null
            hasRange,                   // whether we have a caret/selection
            lastInsertOK,               // last insertion result (or null if none yet)
            lastInsertMessage           // text summary
        });
        return; // sync
        }
    });
}