import 'dart:io';
import 'package:flutter/material.dart' show debugPrint;
import 'package:flutter/services.dart';
import 'package:pdf/pdf.dart';
import 'package:pdf/widgets.dart' as pw;
import 'package:path_provider/path_provider.dart';
import 'package:crypto/crypto.dart';
import 'package:intl/intl.dart';
import '../models/invoice_models.dart';
import 'company_repository.dart';
import 'activity_log_repository.dart';

/// PDFドキュメントの構築（プレビューと実保存の両方で使用）
Future<pw.Document> buildInvoiceDocument(Invoice invoice) async {
  final pdf = pw.Document();

  // フォントのロード
  final fontData = await rootBundle.load("assets/fonts/ipaexg.ttf");
  final ttf = pw.Font.ttf(fontData);
  final boldTtf = pw.Font.ttf(fontData);

  final dateFormatter = DateFormat('yyyy年MM月dd日');
  final amountFormatter = NumberFormat("#,###");

  // 自社情報の取得
  final companyRepo = CompanyRepository();
  final companyInfo = await companyRepo.getCompanyInfo();

  // 印影画像のロード
  pw.MemoryImage? sealImage;
  if (companyInfo.sealPath != null) {
    final file = File(companyInfo.sealPath!);
    if (await file.exists()) {
      final bytes = await file.readAsBytes();
      sealImage = pw.MemoryImage(bytes);
    }
  }

  pdf.addPage(
    pw.MultiPage(
      pageFormat: PdfPageFormat.a4,
      margin: const pw.EdgeInsets.all(32),
      theme: pw.ThemeData.withFont(base: ttf, bold: boldTtf),
      build: (context) => [
        // タイトル
        pw.Header(
          level: 0,
          child: pw.Row(
            mainAxisAlignment: pw.MainAxisAlignment.spaceBetween,
            children: [
              pw.Text(invoice.documentTypeName, style: pw.TextStyle(fontSize: 28, fontWeight: pw.FontWeight.bold)),
              pw.Column(
                crossAxisAlignment: pw.CrossAxisAlignment.end,
                children: [
                  pw.Text("番号: ${invoice.invoiceNumber}"),
                  pw.Text("発行日: ${dateFormatter.format(invoice.date)}"),
                ],
              ),
            ],
          ),
        ),
        pw.SizedBox(height: 20),

        // 宛名と自社情報
        pw.Row(
          crossAxisAlignment: pw.CrossAxisAlignment.start,
          children: [
            pw.Expanded(
              child: pw.Column(
                crossAxisAlignment: pw.CrossAxisAlignment.start,
                children: [
                  pw.Container(
                    decoration: const pw.BoxDecoration(
                      border: pw.Border(bottom: pw.BorderSide(width: 1)),
                    ),
                    child: pw.Text(invoice.customer.invoiceName,
                      style: const pw.TextStyle(fontSize: 18)),
                  ),
                  pw.SizedBox(height: 10),
                  pw.Text(invoice.documentType == DocumentType.receipt 
                    ? "上記の金額を正に領収いたしました。" 
                    : (invoice.documentType == DocumentType.estimation 
                        ? "下記の通り、お見積り申し上げます。" 
                        : "下記の通り、ご請求申し上げます。")),
                ],
              ),
            ),
            pw.Expanded(
              child: pw.Stack(
                alignment: pw.Alignment.topRight,
                children: [
                  pw.Column(
                    crossAxisAlignment: pw.CrossAxisAlignment.end,
                    children: [
                      pw.Text(companyInfo.name, style: pw.TextStyle(fontSize: 14, fontWeight: pw.FontWeight.bold)),
                      if (companyInfo.zipCode != null) pw.Text("〒${companyInfo.zipCode}"),
                      if (companyInfo.address != null) pw.Text(companyInfo.address!),
                      if (companyInfo.tel != null) pw.Text("TEL: ${companyInfo.tel}"),
                    ],
                  ),
                  if (sealImage != null)
                    pw.Positioned(
                      right: 10,
                      top: 0,
                      child: pw.Opacity(
                        opacity: 0.8,
                        child: pw.Image(sealImage, width: 40, height: 40),
                      ),
                    ),
                ],
              ),
            ),
          ],
        ),
        pw.SizedBox(height: 30),

        // 合計金額表示
        pw.Container(
          padding: const pw.EdgeInsets.all(8),
          decoration: const pw.BoxDecoration(color: PdfColors.grey200),
          child: pw.Row(
            mainAxisAlignment: pw.MainAxisAlignment.spaceBetween,
            children: [
              pw.Text(
                invoice.documentType == DocumentType.receipt 
                  ? (companyInfo.taxDisplayMode == 'hidden' ? "領収金額" : "領収金額 (税込)") 
                  : (companyInfo.taxDisplayMode == 'hidden' ? "合計金額" : "合計金額 (税込)"), 
                style: const pw.TextStyle(fontSize: 16)),
              pw.Text("￥${amountFormatter.format(invoice.totalAmount)} -",
                style: pw.TextStyle(fontSize: 20, fontWeight: pw.FontWeight.bold)),
            ],
          ),
        ),
        pw.SizedBox(height: 20),

        // 明細テーブル
        pw.TableHelper.fromTextArray(
          headerStyle: pw.TextStyle(fontWeight: pw.FontWeight.bold),
          headerDecoration: const pw.BoxDecoration(color: PdfColors.grey300),
          cellHeight: 30,
          cellAlignments: {
            0: pw.Alignment.centerLeft,
            1: pw.Alignment.centerRight,
            2: pw.Alignment.centerRight,
            3: pw.Alignment.centerRight,
          },
          headers: ["品名 / 項目", "数量", "単価", "金額"],
          data: List<List<String>>.generate(
            invoice.items.length,
            (index) {
              final item = invoice.items[index];
              return [
                item.description,
                item.quantity.toString(),
                amountFormatter.format(item.unitPrice),
                amountFormatter.format(item.subtotal),
              ];
            },
          ),
        ),

        // 計算内訳
        pw.Row(
          mainAxisAlignment: pw.MainAxisAlignment.end,
          children: [
            pw.Container(
              width: 200,
              child: pw.Column(
                children: [
                  pw.SizedBox(height: 10),
                  _buildSummaryRow("小計 (税抜)", amountFormatter.format(invoice.subtotal)),
                  if (companyInfo.taxDisplayMode == 'normal')
                    _buildSummaryRow("消費税 (${(invoice.taxRate * 100).toInt()}%)", amountFormatter.format(invoice.tax)),
                  if (companyInfo.taxDisplayMode == 'text_only')
                    _buildSummaryRow("消費税", "（税別）"),
                  pw.Divider(),
                  _buildSummaryRow("合計", "￥${amountFormatter.format(invoice.totalAmount)}", isBold: true),
                ],
              ),
            ),
          ],
        ),

        // 備考
        if (invoice.notes != null && invoice.notes!.isNotEmpty) ...[
          pw.SizedBox(height: 40),
          pw.Text("備考:", style: pw.TextStyle(fontWeight: pw.FontWeight.bold)),
          pw.Container(
            width: double.infinity,
            padding: const pw.EdgeInsets.all(8),
            decoration: pw.BoxDecoration(border: pw.Border.all(color: PdfColors.grey400)),
            child: pw.Text(invoice.notes!),
          ),
        ],
      ],
      footer: (context) => pw.Container(
        alignment: pw.Alignment.centerRight,
        margin: const pw.EdgeInsets.only(top: 16),
        child: pw.Text(
          "Page ${context.pageNumber} / ${context.pagesCount}",
          style: const pw.TextStyle(color: PdfColors.grey),
        ),
      ),
    ),
  );

  return pdf;
}

/// A4サイズのプロフェッショナルな伝票PDFを生成し、保存する
Future<String?> generateInvoicePdf(Invoice invoice) async {
  try {
    final pdf = await buildInvoiceDocument(invoice);

    // 保存処理
    final Uint8List bytes = await pdf.save();
    final String hash = sha256.convert(bytes).toString().substring(0, 4);
    final String timeStr = DateFormat('yyyyMMdd_HHmmss').format(DateTime.now());
    String fileName = "${invoice.invoiceNumberPrefix}_${invoice.invoiceNumber}_${timeStr}_$hash.pdf";

    final directory = await getExternalStorageDirectory();
    if (directory == null) return null;

    final file = File("${directory.path}/$fileName");
    await file.writeAsBytes(bytes);

    // 生成をログに記録
    final logRepo = ActivityLogRepository();
    await logRepo.logAction(
      action: "GENERATE_PDF",
      targetType: "INVOICE",
      targetId: invoice.id,
      details: "PDF生成: $fileName (${invoice.documentTypeName})",
    );

    return file.path;
  } catch (e) {
    debugPrint("PDF Generation Error: $e");
    return null;
  }
}

pw.Widget _buildSummaryRow(String label, String value, {bool isBold = false}) {
  final style = pw.TextStyle(fontSize: 12, fontWeight: isBold ? pw.FontWeight.bold : null);
  return pw.Padding(
    padding: const pw.EdgeInsets.symmetric(vertical: 2),
    child: pw.Row(
      mainAxisAlignment: pw.MainAxisAlignment.spaceBetween,
      children: [
        pw.Text(label, style: style),
        pw.Text(value, style: style),
      ],
    ),
  );
}