import 'dart:convert';
import 'dart:typed_data';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart' show rootBundle;
import 'package:flutter_quill/flutter_quill.dart' as quill;
import 'package:pdf/widgets.dart' as pw;
import 'package:pdf/pdf.dart' as pdf;
import 'package:printing/printing.dart';

import '../../models/it_service_request.dart';
import '../../models/it_service_request_assignment.dart';
import '../../models/office.dart';
import '../../models/profile.dart';
import '../../utils/app_time.dart';

/// Build PDF bytes for IT Service Request Form.
Future<Uint8List> buildItServiceRequestPdfBytes({
  required ItServiceRequest request,
  required List<ItServiceRequestAssignment> assignments,
  required Map<String, Profile> profileById,
  required Map<String, Office> officeById,
  pdf.PdfPageFormat? format,
}) async {
  final logoData = await rootBundle.load('assets/crmc_logo.png');
  final logoImage = pw.MemoryImage(logoData.buffer.asUint8List());

  final regularFontData = await rootBundle.load(
    'assets/fonts/Roboto-Regular.ttf',
  );
  final boldFontData = await rootBundle.load('assets/fonts/Roboto-Bold.ttf');
  final regularFont = pw.Font.ttf(regularFontData);
  final boldFont = pw.Font.ttf(boldFontData);

  final doc = pw.Document();

  final officeName = request.officeId != null
      ? officeById[request.officeId]?.name ?? ''
      : '';
  final assignedStaff = assignments
      .map((a) => profileById[a.userId]?.fullName ?? a.userId)
      .toList();
  final eventDetailsText = _plainFromDelta(request.eventDetails);
  final remarksText = _plainFromDelta(request.remarks);
  final selectedServices = request.services;
  final othersText = request.servicesOther ?? '';
  final eventNameWithDetails = eventDetailsText.isEmpty
      ? request.eventName
      : '${request.eventName}: $eventDetailsText';

  final dateTimeReceivedStr = request.dateTimeReceived != null
      ? '${AppTime.formatDate(request.dateTimeReceived!)} ${AppTime.formatTime(request.dateTimeReceived!)}'
      : '';
  final dateTimeCheckedStr = request.dateTimeChecked != null
      ? '${AppTime.formatDate(request.dateTimeChecked!)} ${AppTime.formatTime(request.dateTimeChecked!)}'
      : '';

  final eventDateStr = request.eventDate != null
      ? '${AppTime.formatDate(request.eventDate!)} ${AppTime.formatTime(request.eventDate!)}'
      : '';
  final eventEndStr = request.eventEndDate != null
      ? ' to ${AppTime.formatDate(request.eventEndDate!)} ${AppTime.formatTime(request.eventEndDate!)}'
      : '';
  final dryRunDateStr = request.dryRunDate != null
      ? '${AppTime.formatDate(request.dryRunDate!)} ${AppTime.formatTime(request.dryRunDate!)}'
      : '';
  final dryRunEndStr = request.dryRunEndDate != null
      ? ' to ${AppTime.formatDate(request.dryRunEndDate!)} ${AppTime.formatTime(request.dryRunEndDate!)}'
      : '';

  final smallStyle = pw.TextStyle(fontSize: 8);
  final labelStyle = pw.TextStyle(fontSize: 10);
  final boldLabelStyle = pw.TextStyle(
    fontSize: 10,
    fontWeight: pw.FontWeight.bold,
  );
  final headerItalicStyle = pw.TextStyle(
    fontSize: 10,
    fontStyle: pw.FontStyle.italic,
  );
  final headerBoldStyle = pw.TextStyle(
    fontSize: 11,
    fontWeight: pw.FontWeight.bold,
  );

  doc.addPage(
    pw.MultiPage(
      pageFormat: format ?? pdf.PdfPageFormat.a4,
      margin: const pw.EdgeInsets.symmetric(horizontal: 40, vertical: 28),
      theme: pw.ThemeData.withFont(
        base: regularFont,
        bold: boldFont,
        italic: regularFont,
        boldItalic: boldFont,
      ),
      footer: (pw.Context ctx) => pw.Container(
        alignment: pw.Alignment.centerRight,
        child: pw.Text('MC-IHO-F-17 Rev. 0', style: pw.TextStyle(fontSize: 8)),
      ),
      build: (pw.Context ctx) => [
        // ── Header ──
        pw.Row(
          mainAxisAlignment: pw.MainAxisAlignment.center,
          crossAxisAlignment: pw.CrossAxisAlignment.center,
          children: [
            pw.Container(width: 64, height: 64, child: pw.Image(logoImage)),
            pw.SizedBox(width: 12),
            pw.Column(
              mainAxisSize: pw.MainAxisSize.min,
              crossAxisAlignment: pw.CrossAxisAlignment.center,
              children: [
                pw.Text(
                  'Republic of the Philippines',
                  style: headerItalicStyle,
                ),
                pw.Text('Department of Health', style: headerItalicStyle),
                pw.Text(
                  'COTABATO REGIONAL AND MEDICAL CENTER',
                  style: headerBoldStyle,
                ),
                pw.SizedBox(height: 6),
                pw.Text(
                  'INTEGRATED HOSPITAL OPERATIONS AND MANAGEMENT PROGRAM',
                  style: pw.TextStyle(
                    fontSize: 9,
                    fontWeight: pw.FontWeight.bold,
                  ),
                ),
                pw.Text(
                  'IHOMP',
                  style: pw.TextStyle(
                    fontSize: 9,
                    fontWeight: pw.FontWeight.bold,
                  ),
                ),
              ],
            ),
          ],
        ),
        pw.SizedBox(height: 14),

        // ── Title ──
        pw.Center(
          child: pw.Text(
            'IT SERVICE REQUEST FORM',
            style: pw.TextStyle(fontSize: 13, fontWeight: pw.FontWeight.bold),
          ),
        ),
        pw.SizedBox(height: 14),

        // ── Note + Date/Time Received/Checked ──
        pw.Row(
          crossAxisAlignment: pw.CrossAxisAlignment.start,
          children: [
            pw.Expanded(
              flex: 3,
              child: pw.Text(
                '* Ensure availability of venue, power supply, sound system, '
                'microphone, power point presentation, videos, music and '
                'other necessary files needed for the event of activity.',
                style: pw.TextStyle(
                  fontSize: 8,
                  fontStyle: pw.FontStyle.italic,
                ),
              ),
            ),
            pw.SizedBox(width: 16),
            pw.Expanded(
              flex: 2,
              child: pw.Column(
                crossAxisAlignment: pw.CrossAxisAlignment.start,
                children: [
                  _underlineField(
                    'Date/Time Received:',
                    dateTimeReceivedStr,
                    style: labelStyle,
                  ),
                  pw.SizedBox(height: 6),
                  _underlineField(
                    'Date/Time Checked:',
                    dateTimeCheckedStr,
                    style: labelStyle,
                  ),
                ],
              ),
            ),
          ],
        ),
        pw.SizedBox(height: 14),

        // ── Services ──
        pw.Text('Services', style: boldLabelStyle),
        pw.SizedBox(height: 6),
        // Row 1: FB Live Stream, Technical Assistance, Others
        pw.Row(
          children: [
            pw.Expanded(
              child: _checkbox(
                'FB Live Stream',
                selectedServices.contains(ItServiceType.fbLiveStream),
                style: labelStyle,
              ),
            ),
            pw.Expanded(
              child: _checkbox(
                'Technical Assistance',
                selectedServices.contains(ItServiceType.technicalAssistance),
                style: labelStyle,
              ),
            ),
            pw.Expanded(
              child: _checkbox(
                'Others${othersText.isNotEmpty ? ' ($othersText)' : ''}',
                selectedServices.contains(ItServiceType.others),
                style: labelStyle,
              ),
            ),
          ],
        ),
        pw.SizedBox(height: 2),
        // Row 2: Video Recording, WiFi
        pw.Row(
          children: [
            pw.Expanded(
              child: _checkbox(
                'Video Recording',
                selectedServices.contains(ItServiceType.videoRecording),
                style: labelStyle,
              ),
            ),
            pw.Expanded(
              child: _checkbox(
                'WiFi',
                selectedServices.contains(ItServiceType.wifi),
                style: labelStyle,
              ),
            ),
            pw.Expanded(child: pw.SizedBox()),
          ],
        ),
        pw.SizedBox(height: 14),

        // ── Event/Activity Details ──
        pw.Text('Event/Activity Details', style: boldLabelStyle),
        _underlineField('Event Name', eventNameWithDetails, style: labelStyle),
        pw.SizedBox(height: 14),

        // ── 4-column: Event Date/Time, Dry Run, Contact Person, Contact Number ──
        pw.Row(
          crossAxisAlignment: pw.CrossAxisAlignment.start,
          children: [
            pw.Expanded(
              child: pw.Column(
                crossAxisAlignment: pw.CrossAxisAlignment.start,
                children: [
                  pw.Text('Event Date and Time', style: smallStyle),
                  pw.SizedBox(height: 4),
                  _underlinedText(
                    '$eventDateStr$eventEndStr',
                    style: smallStyle,
                  ),
                ],
              ),
            ),
            pw.SizedBox(width: 8),
            pw.Expanded(
              child: pw.Column(
                crossAxisAlignment: pw.CrossAxisAlignment.start,
                children: [
                  pw.Text('Dry Run Date and Time', style: smallStyle),
                  pw.SizedBox(height: 4),
                  _underlinedText(
                    '$dryRunDateStr$dryRunEndStr',
                    style: smallStyle,
                  ),
                ],
              ),
            ),
            pw.SizedBox(width: 8),
            pw.Expanded(
              child: pw.Column(
                crossAxisAlignment: pw.CrossAxisAlignment.start,
                children: [
                  pw.Text('Contact Person', style: smallStyle),
                  pw.SizedBox(height: 4),
                  _underlinedText(
                    request.contactPerson ?? '',
                    style: smallStyle,
                  ),
                ],
              ),
            ),
            pw.SizedBox(width: 8),
            pw.Expanded(
              child: pw.Column(
                crossAxisAlignment: pw.CrossAxisAlignment.start,
                children: [
                  pw.Text('Contact Number', style: smallStyle),
                  pw.SizedBox(height: 4),
                  _underlinedText(
                    request.contactNumber ?? '',
                    style: smallStyle,
                  ),
                ],
              ),
            ),
          ],
        ),
        pw.SizedBox(height: 14),

        // ── IT Staff/s Assigned ──
        pw.Text('IT Staff/s Assigned', style: boldLabelStyle),
        pw.SizedBox(height: 4),
        // Show each staff on a separate underlined row, or empty lines
        if (assignedStaff.isNotEmpty)
          ...assignedStaff.map(
            (name) => pw.Padding(
              padding: const pw.EdgeInsets.only(bottom: 4),
              child: _underlinedText(name, style: labelStyle),
            ),
          )
        else ...[
          _underlinedText('', style: labelStyle),
          pw.SizedBox(height: 4),
          _underlinedText('', style: labelStyle),
        ],
        pw.SizedBox(height: 14),

        // ── Remarks ──
        pw.Text('Remarks:', style: boldLabelStyle),
        pw.SizedBox(height: 4),
        pw.Container(
          width: double.infinity,
          constraints: const pw.BoxConstraints(minHeight: 60),
          padding: const pw.EdgeInsets.all(4),
          child: pw.Text(remarksText, style: labelStyle),
        ),
        pw.SizedBox(height: 28),

        // ── Signature blocks ──
        pw.Row(
          crossAxisAlignment: pw.CrossAxisAlignment.start,
          children: [
            // Left: Requested by
            pw.Expanded(
              child: pw.Column(
                crossAxisAlignment: pw.CrossAxisAlignment.start,
                children: [
                  pw.Text('Requested by:', style: labelStyle),
                  pw.SizedBox(height: 36),
                  pw.Container(
                    width: double.infinity,
                    decoration: const pw.BoxDecoration(
                      border: pw.Border(bottom: pw.BorderSide(width: 0.8)),
                    ),
                    padding: const pw.EdgeInsets.only(bottom: 2),
                    child: pw.Center(
                      child: pw.Text(
                        request.requestedBy ?? '',
                        style: boldLabelStyle,
                      ),
                    ),
                  ),
                  pw.SizedBox(height: 2),
                  pw.Center(
                    child: pw.Text(
                      'Signature over printed name',
                      style: smallStyle,
                    ),
                  ),
                  pw.SizedBox(height: 10),
                  _underlineField('Department:', officeName, style: labelStyle),
                  pw.SizedBox(height: 6),
                  _underlineField(
                    'Date:',
                    AppTime.formatDate(request.createdAt),
                    style: labelStyle,
                  ),
                ],
              ),
            ),
            pw.SizedBox(width: 40),
            // Right: Approved by
            pw.Expanded(
              child: pw.Column(
                crossAxisAlignment: pw.CrossAxisAlignment.start,
                children: [
                  pw.Text('Approved by:', style: labelStyle),
                  pw.SizedBox(height: 36),
                  pw.Container(
                    width: double.infinity,
                    decoration: const pw.BoxDecoration(
                      border: pw.Border(bottom: pw.BorderSide(width: 0.8)),
                    ),
                    padding: const pw.EdgeInsets.only(bottom: 2),
                    child: pw.Center(
                      child: pw.Text(
                        request.approvedBy ?? '',
                        style: boldLabelStyle,
                      ),
                    ),
                  ),
                  pw.SizedBox(height: 2),
                  pw.Center(
                    child: pw.Text('IHOMP \u2013 Head', style: smallStyle),
                  ),
                  pw.SizedBox(height: 10),
                  _underlineField(
                    'Date:',
                    request.approvedAt != null
                        ? AppTime.formatDate(request.approvedAt!)
                        : '',
                    style: labelStyle,
                  ),
                ],
              ),
            ),
          ],
        ),
        pw.SizedBox(height: 12),
      ],
    ),
  );

  return doc.save();
}

/// A checkbox with label, matching the form layout.
pw.Widget _checkbox(String label, bool checked, {pw.TextStyle? style}) {
  return pw.Row(
    mainAxisSize: pw.MainAxisSize.min,
    children: [
      pw.Container(
        width: 10,
        height: 10,
        decoration: pw.BoxDecoration(border: pw.Border.all(width: 0.8)),
        child: checked
            ? pw.Center(
                child: pw.Text(
                  'X',
                  style: pw.TextStyle(
                    fontSize: 7,
                    fontWeight: pw.FontWeight.bold,
                  ),
                ),
              )
            : null,
      ),
      pw.SizedBox(width: 4),
      pw.Text(label, style: style),
    ],
  );
}

/// A label followed by an underlined value, e.g. "Date/Time Received: ____"
pw.Widget _underlineField(String label, String value, {pw.TextStyle? style}) {
  return pw.Row(
    crossAxisAlignment: pw.CrossAxisAlignment.end,
    children: [
      pw.Text(label, style: style),
      pw.SizedBox(width: 4),
      pw.Expanded(
        child: pw.Container(
          decoration: const pw.BoxDecoration(
            border: pw.Border(bottom: pw.BorderSide(width: 0.8)),
          ),
          padding: const pw.EdgeInsets.only(bottom: 2),
          child: pw.Text(value, style: style),
        ),
      ),
    ],
  );
}

/// Text with an underline spanning the full width.
pw.Widget _underlinedText(String value, {pw.TextStyle? style}) {
  return pw.Container(
    width: double.infinity,
    decoration: const pw.BoxDecoration(
      border: pw.Border(bottom: pw.BorderSide(width: 0.5)),
    ),
    padding: const pw.EdgeInsets.only(bottom: 2),
    child: pw.Text(value, style: style),
  );
}

String _plainFromDelta(String? deltaJson) {
  if (deltaJson == null || deltaJson.trim().isEmpty) return '';
  dynamic decoded = deltaJson;
  for (var i = 0; i < 3; i++) {
    if (decoded is String) {
      try {
        decoded = jsonDecode(decoded);
        continue;
      } catch (_) {
        break;
      }
    }
    break;
  }

  if (decoded is Map && decoded['ops'] is List) {
    final ops = decoded['ops'] as List;
    final buf = StringBuffer();
    for (final op in ops) {
      if (op is Map) {
        final insert = op['insert'];
        if (insert is String) {
          buf.write(insert);
        }
      }
    }
    return buf.toString().trim();
  }

  if (decoded is List) {
    try {
      final doc = quill.Document.fromJson(decoded);
      return doc.toPlainText().trim();
    } catch (_) {
      return decoded.join();
    }
  }
  return decoded.toString();
}

/// Generate and share/print the IT Service Request PDF.
Future<void> generateItServiceRequestPdf({
  required BuildContext context,
  required ItServiceRequest request,
  required List<ItServiceRequestAssignment> assignments,
  required Map<String, Profile> profileById,
  required Map<String, Office> officeById,
  Uint8List? prebuiltBytes,
}) async {
  final bytes =
      prebuiltBytes ??
      await buildItServiceRequestPdfBytes(
        request: request,
        assignments: assignments,
        profileById: profileById,
        officeById: officeById,
      );
  await Printing.layoutPdf(
    onLayout: (_) async => bytes,
    name: 'ISR-${request.requestNumber ?? request.id}.pdf',
  );
}