import {
  DEV_PLAN_TASK_STATUS_LABELS,
  DEV_PLAN_TASK_TYPE_LABELS,
  type DevPlanTaskStatusDto,
  type DevPlanTaskTypeDto,
} from '@dukang/shared-types';
import ExcelJS from 'exceljs';
import * as fs from 'fs';
import * as path from 'path';
import PDFDocument from 'pdfkit';
import {
  Document,
  HeadingLevel,
  ImageRun,
  Packer,
  Paragraph,
  Table,
  TableCell,
  TableRow,
  TextRun,
  WidthType,
} from 'docx';

const EXPORT_HEADERS = [
  '任务编号',
  '类型',
  '状态',
  '内容',
  '关联工单',
  '创建人',
  '创建时间',
  '完成时间',
  '附件',
] as const;

export type DevPlanTaskExportRow = {
  taskNo: string;
  type: string;
  status: string;
  content: string;
  supportTicketNo: string;
  creatorName: string;
  createdAt: string;
  completedAt: string;
  attachmentUrls: string[];
};

export type DevPlanExportFormat = 'markdown' | 'docx' | 'xlsx' | 'pdf';

export function mapTaskToExportRow(task: {
  taskNo: string;
  type: DevPlanTaskTypeDto;
  status: DevPlanTaskStatusDto;
  content: string;
  supportTicketNo?: string | null;
  creatorName?: string | null;
  createdAt: string;
  completedAt?: string | null;
  attachmentUrls?: string[] | null;
}): DevPlanTaskExportRow {
  return {
    taskNo: task.taskNo,
    type: DEV_PLAN_TASK_TYPE_LABELS[task.type] ?? task.type,
    status: DEV_PLAN_TASK_STATUS_LABELS[task.status] ?? task.status,
    content: task.content,
    supportTicketNo: task.supportTicketNo ?? '',
    creatorName: task.creatorName ?? '',
    createdAt: task.createdAt.slice(0, 19).replace('T', ' '),
    completedAt: task.completedAt ? task.completedAt.slice(0, 19).replace('T', ' ') : '',
    attachmentUrls: task.attachmentUrls ?? [],
  };
}

function rowToCells(row: DevPlanTaskExportRow): string[] {
  return [
    row.taskNo,
    row.type,
    row.status,
    row.content,
    row.supportTicketNo,
    row.creatorName,
    row.createdAt,
    row.completedAt,
    row.attachmentUrls.join(' '),
  ];
}

function resolvePdfFontPath(): string {
  const candidates = [
    process.env.EXPORT_PDF_FONT_PATH,
    path.join(process.cwd(), 'assets', 'fonts', 'NotoSansSC-Regular.otf'),
    path.join(process.cwd(), 'assets', 'fonts', 'simhei.ttf'),
    path.join(process.cwd(), 'assets', 'fonts', 'msyh.ttc'),
    path.join(process.cwd(), 'dist', 'assets', 'fonts', 'simhei.ttf'),
    '/usr/share/fonts/truetype/noto/NotoSansCJK-Regular.ttc',
    'C:\\Windows\\Fonts\\simhei.ttf',
    'C:\\Windows\\Fonts\\msyh.ttc',
  ].filter(Boolean) as string[];
  for (const candidate of candidates) {
    if (fs.existsSync(candidate)) return candidate;
  }
  throw new Error('未找到可用于 PDF 的中文字体，请将字体文件放到 server/dukang-api/assets/fonts/');
}

export function buildDevPlanMarkdown(rows: DevPlanTaskExportRow[]): Buffer {
  const lines: string[] = ['# 开发计划任务导出', ''];
  rows.forEach((row, index) => {
    lines.push(`## ${index + 1}. ${row.taskNo} [${row.type}] ${row.status}`);
    lines.push('');
    lines.push(row.content);
    lines.push('');
    if (row.supportTicketNo) lines.push(`- 关联工单：${row.supportTicketNo}`);
    if (row.creatorName) lines.push(`- 创建人：${row.creatorName}`);
    lines.push(`- 创建时间：${row.createdAt}`);
    if (row.completedAt) lines.push(`- 完成时间：${row.completedAt}`);
    if (row.attachmentUrls.length) {
      lines.push('- 附件：');
      for (const url of row.attachmentUrls) {
        lines.push(`  ![附件](${url})`);
        lines.push(`  ${url}`);
      }
    }
    lines.push('');
  });
  return Buffer.from(lines.join('\n'), 'utf8');
}

async function fetchImageBuffer(url: string): Promise<Buffer | null> {
  try {
    const res = await fetch(url, { signal: AbortSignal.timeout(8000) });
    if (!res.ok) return null;
    const buf = Buffer.from(await res.arrayBuffer());
    return buf.length > 0 && buf.length < 5 * 1024 * 1024 ? buf : null;
  } catch {
    return null;
  }
}

export async function buildDevPlanDocx(rows: DevPlanTaskExportRow[]): Promise<Buffer> {
  const children: (Paragraph | Table)[] = [
    new Paragraph({ text: '开发计划任务导出', heading: HeadingLevel.HEADING_1 }),
  ];

  for (const row of rows) {
    children.push(
      new Paragraph({
        text: `${row.taskNo} [${row.type}] ${row.status}`,
        heading: HeadingLevel.HEADING_2,
      }),
      new Paragraph({ children: [new TextRun(row.content)] }),
      new Paragraph({
        children: [
          new TextRun(`创建人：${row.creatorName || '—'}  创建：${row.createdAt}`),
        ],
      }),
    );
    if (row.supportTicketNo) {
      children.push(new Paragraph({ children: [new TextRun(`关联工单：${row.supportTicketNo}`)] }));
    }
    if (row.completedAt) {
      children.push(new Paragraph({ children: [new TextRun(`完成时间：${row.completedAt}`)] }));
    }
    for (const url of row.attachmentUrls) {
      const img = await fetchImageBuffer(url);
      if (img) {
        children.push(
          new Paragraph({
            children: [
              new ImageRun({
                data: img,
                transformation: { width: 320, height: 240 },
                type: 'png',
              }),
            ],
          }),
        );
      } else {
        children.push(new Paragraph({ children: [new TextRun(url)] }));
      }
    }
    children.push(new Paragraph({ text: '' }));
  }

  const doc = new Document({
    sections: [{ children }],
  });
  return Packer.toBuffer(doc);
}

export async function buildDevPlanXlsx(rows: DevPlanTaskExportRow[]): Promise<Buffer> {
  const workbook = new ExcelJS.Workbook();
  const sheet = workbook.addWorksheet('开发任务');
  sheet.addRow([...EXPORT_HEADERS]);
  for (const row of rows) {
    sheet.addRow(rowToCells(row));
  }
  sheet.columns.forEach((col, i) => {
    col.width = i === 3 || i === 8 ? 40 : 16;
  });
  const buffer = await workbook.xlsx.writeBuffer();
  return Buffer.from(buffer);
}

export async function buildDevPlanPdf(rows: DevPlanTaskExportRow[]): Promise<Buffer> {
  const fontPath = resolvePdfFontPath();
  const chunks: Buffer[] = [];

  return new Promise((resolve, reject) => {
    const doc = new PDFDocument({ size: 'A4', layout: 'landscape', margin: 24, bufferPages: true });
    doc.on('data', (chunk) => chunks.push(chunk as Buffer));
    doc.on('end', () => resolve(Buffer.concat(chunks)));
    doc.on('error', reject);
    doc.registerFont('zh', fontPath);
    doc.font('zh');

    const pageWidth = doc.page.width - doc.page.margins.left - doc.page.margins.right;
    const colWidths = [72, 48, 48, 180, 72, 56, 78, 78, 120];
    const scale = pageWidth / colWidths.reduce((s, w) => s + w, 0);
    const widths = colWidths.map((w) => w * scale);
    const rowHeight = 36;
    let y = doc.page.margins.top;

    const drawRow = (cells: string[], isHeader = false) => {
      let x = doc.page.margins.left;
      const height = isHeader ? 24 : rowHeight;
      if (y + height > doc.page.height - doc.page.margins.bottom) {
        doc.addPage({ size: 'A4', layout: 'landscape', margin: 24 });
        y = doc.page.margins.top;
      }
      doc.fontSize(isHeader ? 8 : 7);
      cells.forEach((cell, index) => {
        doc.rect(x, y, widths[index], height).stroke('#dddddd');
        doc.text(cell || '', x + 2, y + 4, {
          width: widths[index] - 4,
          height: height - 6,
          lineBreak: true,
        });
        x += widths[index];
      });
      y += height;
    };

    drawRow([...EXPORT_HEADERS], true);
    for (const row of rows) {
      drawRow(rowToCells(row));
    }
    doc.end();
  });
}

export function buildDevPlanExportFilename(format: DevPlanExportFormat, count: number): string {
  const stamp = new Date().toISOString().slice(0, 10);
  const ext = format === 'markdown' ? 'md' : format === 'docx' ? 'docx' : format;
  return `开发任务导出_${stamp}_${count}条.${ext}`;
}

export function devPlanExportMimeType(format: DevPlanExportFormat): string {
  switch (format) {
    case 'markdown':
      return 'text/markdown;charset=utf-8';
    case 'docx':
      return 'application/vnd.openxmlformats-officedocument.wordprocessingml.document';
    case 'xlsx':
      return 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet';
    case 'pdf':
      return 'application/pdf';
    default:
      return 'application/octet-stream';
  }
}