// Note Editor: manages review notes with auto-save and three-level scoping
// Scopes: overall (page-level), file (per-file), suggestion (per-suggestion)
const NoteEditor = {
    repoId: null,
    analysisId: null,
    _saveTimers: {},  // debounce timers by key
    _notes: {},       // loaded notes keyed by "scope:scopeKey"

    /**
     * Initialize the note editor for a review page.
     * @param {number} repoId - Repository ID
     * @param {number} analysisId - Analysis ID (from the most recent review)
     */
    init(repoId, analysisId) {
        this.repoId = repoId;
        this.analysisId = analysisId;
        this._notes = {};
        this._saveTimers = {};

        // Bind existing note editor placeholders (from diff-viewer suggestion cards)
        this._bindPlaceholders();

        // Watch for new placeholders added dynamically (from SSE streaming)
        this._observeNewPlaceholders();
    },

    /**
     * Load all notes for the current analysis and populate editors.
     */
    async loadNotes() {
        if (!this.analysisId) return;

        try {
            const resp = await fetch(`/api/repos/${this.repoId}/review/notes?analysis_id=${this.analysisId}`);
            if (!resp.ok) return;
            const notes = await resp.json();

            // Index notes
            notes.forEach(n => {
                const key = n.scope + ':' + (n.scope_key || '');
                this._notes[key] = n;
            });

            // Populate all existing editors
            this._populateAllEditors();
        } catch (err) {
            console.error('Failed to load notes:', err);
        }
    },

    /**
     * Save a note (upsert). Debounced to avoid rapid-fire requests.
     */
    saveNote(scope, scopeKey, content) {
        const key = scope + ':' + (scopeKey || '');

        // Clear existing timer for this key
        if (this._saveTimers[key]) {
            clearTimeout(this._saveTimers[key]);
        }

        // Debounce: wait 800ms after last keystroke
        this._saveTimers[key] = setTimeout(async () => {
            delete this._saveTimers[key];

            try {
                const resp = await fetch(`/api/repos/${this.repoId}/review/notes`, {
                    method: 'POST',
                    headers: { 'Content-Type': 'application/json' },
                    body: JSON.stringify({
                        analysis_id: this.analysisId,
                        scope: scope,
                        scope_key: scopeKey || '',
                        content: content,
                    }),
                });

                if (resp.ok) {
                    const note = await resp.json();
                    this._notes[key] = note;

                    // Update save indicator
                    const indicator = document.querySelector(`[data-note-key="${key}"] .note-save-indicator`);
                    if (indicator) {
                        indicator.textContent = '已保存';
                        indicator.classList.remove('text-gray-400');
                        indicator.classList.add('text-green-500');
                        setTimeout(() => {
                            indicator.textContent = '';
                            indicator.classList.remove('text-green-500');
                        }, 2000);
                    }
                }
            } catch (err) {
                console.error('Failed to save note:', err);
            }
        }, 800);
    },

    /**
     * Create a note editor HTML for a given scope.
     * @param {string} scope - 'overall', 'file', or 'suggestion'
     * @param {string} scopeKey - empty for overall, filename for file, suggestionId for suggestion
     * @returns {string} HTML string
     */
    createEditorHTML(scope, scopeKey) {
        const key = scope + ':' + (scopeKey || '');
        const existing = this._notes[key];
        const content = existing ? existing.content : '';
        const placeholder = this._getPlaceholder(scope);

        return `
            <div class="note-editor mt-2" data-note-key="${key}" data-scope="${scope}" data-scope-key="${scopeKey || ''}">
                <div class="flex items-center justify-between mb-1">
                    <span class="text-xs text-gray-400">💬 备注 (Markdown)</span>
                    <span class="note-save-indicator text-xs"></span>
                </div>
                <textarea
                    class="note-textarea"
                    placeholder="${placeholder}"
                    rows="2"
                    oninput="NoteEditor.onInput(this, '${scope}', '${scopeKey || ''}')"
                >${this._escapeHtml(content)}</textarea>
            </div>`;
    },

    /**
     * Render a standalone "overall" note editor section (for the review page).
     */
    renderOverallEditor() {
        if (!this.analysisId) return '';
        return `
            <div id="overall-note-section" class="bg-white rounded-lg shadow-md p-6 mb-6">
                <h2 class="text-lg font-semibold text-gray-900 mb-3">📝 整体备注</h2>
                ${this.createEditorHTML('overall', '')}
            </div>`;
    },

    /**
     * Render a "PDF Export" button.
     */
    renderPDFButton() {
        return `
            <button onclick="NoteEditor.exportPDF()" id="btn-export-pdf"
                    class="px-4 py-2 bg-indigo-600 text-white rounded-md hover:bg-indigo-700 text-sm">
                📄 导出 PDF 报告
            </button>`;
    },

    /**
     * Trigger PDF export and download.
     */
    async exportPDF() {
        if (!this.analysisId) {
            alert('请先完成审查再导出 PDF');
            return;
        }

        const btn = document.getElementById('btn-export-pdf');
        if (btn) {
            btn.disabled = true;
            btn.textContent = '⏳ 生成中...';
        }

        try {
            const resp = await fetch(`/api/repos/${this.repoId}/review/pdf`, {
                method: 'POST',
                headers: { 'Content-Type': 'application/json' },
                body: JSON.stringify({
                    analysis_id: this.analysisId,
                    base: document.getElementById('base-ref')?.value || '',
                    head: document.getElementById('head-ref')?.value || '',
                }),
            });

            if (!resp.ok) {
                const err = await resp.json();
                throw new Error(err.error || 'PDF generation failed');
            }

            // Download the PDF
            const blob = await resp.blob();
            const url = URL.createObjectURL(blob);
            const a = document.createElement('a');
            a.href = url;
            a.download = `pr-helper-review-${new Date().toISOString().slice(0, 10)}.pdf`;
            document.body.appendChild(a);
            a.click();
            document.body.removeChild(a);
            URL.revokeObjectURL(url);
        } catch (err) {
            alert('PDF 导出失败: ' + err.message);
        } finally {
            if (btn) {
                btn.disabled = false;
                btn.textContent = '📄 导出 PDF 报告';
            }
        }
    },

    // ── Internal helpers ──────────────────────────────────────────

    _getPlaceholder(scope) {
        switch (scope) {
            case 'overall': return '添加整体备注...';
            case 'file': return '添加文件级备注...';
            case 'suggestion': return '添加备注...';
            default: return '添加备注...';
        }
    },

    _escapeHtml(text) {
        const div = document.createElement('div');
        div.textContent = text || '';
        return div.innerHTML;
    },

    onInput(textarea, scope, scopeKey) {
        // Update save indicator to "saving..."
        const key = scope + ':' + (scopeKey || '');
        const indicator = textarea.closest('.note-editor')?.querySelector('.note-save-indicator');
        if (indicator) {
            indicator.textContent = '保存中...';
            indicator.classList.remove('text-green-500');
            indicator.classList.add('text-gray-400');
        }

        this.saveNote(scope, scopeKey, textarea.value);
    },

    /**
     * Bind click/input handlers to existing note-editor-placeholder divs.
     */
    _bindPlaceholders() {
        document.querySelectorAll('.note-editor-placeholder').forEach(placeholder => {
            if (placeholder.dataset.initialized) return;
            placeholder.dataset.initialized = 'true';

            const scope = placeholder.dataset.scope || 'suggestion';
            const scopeKey = placeholder.dataset.scopeKey || '';

            placeholder.innerHTML = this.createEditorHTML(scope, scopeKey);
        });
    },

    /**
     * Populate all note editors with loaded content.
     */
    _populateAllEditors() {
        document.querySelectorAll('.note-editor').forEach(editor => {
            const key = editor.dataset.noteKey;
            const note = this._notes[key];
            if (note && note.content) {
                const textarea = editor.querySelector('.note-textarea');
                if (textarea && !textarea.value) {
                    textarea.value = note.content;
                }
            }
        });
    },

    /**
     * Observe DOM for new note-editor-placeholder elements (from SSE streaming).
     */
    _observeNewPlaceholders() {
        const observer = new MutationObserver((mutations) => {
            let hasNew = false;
            for (const mutation of mutations) {
                for (const node of mutation.addedNodes) {
                    if (node.nodeType !== 1) continue;
                    if (node.classList?.contains('note-editor-placeholder') ||
                        node.querySelector?.('.note-editor-placeholder')) {
                        hasNew = true;
                        break;
                    }
                }
                if (hasNew) break;
            }
            if (hasNew) {
                this._bindPlaceholders();
                this._populateAllEditors();
            }
        });

        observer.observe(document.body, { childList: true, subtree: true });
    },

    /**
     * Set the analysis ID (called after a review completes and analysis is saved).
     */
    setAnalysisId(id) {
        this.analysisId = id;
    },
};

window.NoteEditor = NoteEditor;