import 'dart:convert';

import 'package:flutter/material.dart';
import 'package:flutter_quill/flutter_quill.dart' as quill;

/// Convert a stored Delta JSON or plain text string to trimmed plain text.
/// - Delta JSON (starts with '[') is decoded and converted to plain text
/// - Non-JSON strings are returned trimmed as-is
/// - null returns empty string
String deltaJsonToPlainText(String? stored) {
  if (stored == null) return '';
  final trimmed = stored.trim();
  if (trimmed.isEmpty) return '';
  if (trimmed.startsWith('[')) {
    try {
      final decoded = jsonDecode(trimmed);
      if (decoded is List) {
        final doc = quill.Document.fromJson(decoded);
        return doc.toPlainText().trim();
      }
    } catch (_) {}
  }
  return trimmed;
}

/// Parses a stored Delta-JSON string into a [quill.QuillController], or returns
/// an empty one. Callers own the controller and must dispose it.
quill.QuillController quillControllerFromDelta(String? deltaJson) {
  if (deltaJson != null && deltaJson.isNotEmpty) {
    try {
      final decoded = jsonDecode(deltaJson);
      if (decoded is List) {
        return quill.QuillController(
          document: quill.Document.fromJson(decoded),
          selection: const TextSelection.collapsed(offset: 0),
        );
      }
    } catch (_) {}
  }
  return quill.QuillController.basic();
}

/// Serializes a controller's document to a Delta-JSON string for storage.
String quillToDeltaJson(quill.QuillController controller) =>
    jsonEncode(controller.document.toDelta().toJson());

/// The controller's plain text (trimmed) — for empty checks and previews.
String quillPlainText(quill.QuillController controller) =>
    controller.document.toPlainText().trim();

/// Bordered rich-text editor with a minimal toolbar (bold/italic/underline +
/// bullet/numbered lists). The caller owns [controller] and disposes it.
class QuillFieldEditor extends StatelessWidget {
  const QuillFieldEditor({
    super.key,
    required this.controller,
    this.placeholder,
    this.height = 140,
  });

  final quill.QuillController controller;
  final String? placeholder;
  final double height;

  @override
  Widget build(BuildContext context) {
    final cs = Theme.of(context).colorScheme;
    return Container(
      height: height,
      clipBehavior: Clip.antiAlias,
      decoration: BoxDecoration(
        border: Border.all(color: cs.outlineVariant),
        borderRadius: BorderRadius.circular(8),
      ),
      child: Column(
        children: [
          SizedBox(
            height: 40,
            child: quill.QuillSimpleToolbar(
              controller: controller,
              config: const quill.QuillSimpleToolbarConfig(
                multiRowsDisplay: false,
                showAlignmentButtons: false,
                showBackgroundColorButton: false,
                showCenterAlignment: false,
                showColorButton: false,
                showDividers: false,
                showFontFamily: false,
                showFontSize: false,
                showHeaderStyle: false,
                showIndent: false,
                showInlineCode: false,
                showLeftAlignment: false,
                showLink: false,
                showQuote: false,
                showRightAlignment: false,
                showSearchButton: false,
                showCodeBlock: false,
                showDirection: false,
                showJustifyAlignment: false,
                showListCheck: false,
                showSubscript: false,
                showSuperscript: false,
                showStrikeThrough: false,
                showSmallButton: false,
                showClearFormat: false,
                showRedo: false,
                showUndo: false,
              ),
            ),
          ),
          const Divider(height: 1),
          Expanded(
            child: Padding(
              padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 6),
              child: quill.QuillEditor.basic(
                controller: controller,
                config: quill.QuillEditorConfig(
                  placeholder: placeholder,
                  expands: true,
                ),
              ),
            ),
          ),
        ],
      ),
    );
  }
}

/// Renders a stored value read-only. Interprets a Delta-JSON string as rich
/// text; falls back to a plain [Text] for legacy plain-string values.
class QuillReadOnly extends StatelessWidget {
  const QuillReadOnly(this.deltaOrText, {super.key, this.style});

  final String deltaOrText;
  final TextStyle? style;

  @override
  Widget build(BuildContext context) {
    final trimmed = deltaOrText.trim();
    if (trimmed.startsWith('[')) {
      try {
        final decoded = jsonDecode(trimmed);
        if (decoded is List) {
          final controller = quill.QuillController(
            document: quill.Document.fromJson(decoded),
            selection: const TextSelection.collapsed(offset: 0),
          );
          return IgnorePointer(
            child: quill.QuillEditor.basic(
              controller: controller,
              config: const quill.QuillEditorConfig(
                showCursor: false,
                autoFocus: false,
              ),
            ),
          );
        }
      } catch (_) {}
    }
    return Text(deltaOrText, style: style);
  }
}