/**
 * GB/T 9704-2012 公文格式常量
 * 供所有公文文档生成脚本共享
 */

const { AlignmentType, BorderStyle, WidthType, ShadingType, LevelFormat,
        HeadingLevel, Paragraph, TextRun, Table, TableRow, TableCell,
        Header, Footer, PageNumber } = require("docx");

// ─── 页面 ─────────────────────────────────────────────────
const PAGE = {
  WIDTH:  11906,  // 210mm
  HEIGHT: 16838,  // 297mm
  MARGIN_TOP:    2098,  // 37mm
  MARGIN_BOTTOM: 1985,  // 35mm
  MARGIN_LEFT:   1588,  // 28mm
  MARGIN_RIGHT:  1474,  // 26mm
  CONTENT_WIDTH: 8844,  // 210 - 28 - 26 mm
};

// ─── 字体 ─────────────────────────────────────────────────
const FONT = {
  HEITI:    { ascii: "SimHei",   eastAsia: "黑体",  hAnsi: "SimHei"   },
  FANGSONG: { ascii: "FangSong", eastAsia: "仿宋",  hAnsi: "FangSong" },
  KAITI:    { ascii: "KaiTi",    eastAsia: "楷体",  hAnsi: "KaiTi"    },
  SONGTI:   { ascii: "SimSun",   eastAsia: "宋体",  hAnsi: "SimSun"   },
};

// ─── 字号（half-point） ───────────────────────────────────
const SIZE = {
  ER_HAO:   44,  // 二号 22pt
  SAN_HAO:  32,  // 三号 16pt
  SI_HAO:   28,  // 四号 14pt
  XIAO_SI:  24,  // 小四 12pt
  WU_HAO:   21,  // 五号 10.5pt
};

// ─── 行距（twips = pt × 20） ─────────────────────────────
const LINE = {
  BODY:     { line: 560, lineRule: "exact" },  // 28pt
  HEADING1: { line: 640, lineRule: "exact" },  // 32pt
  HEADING2: { line: 560, lineRule: "exact" },  // 28pt
  TABLE:    { line: 440, lineRule: "exact" },  // 22pt
  TITLE:    { line: 640, lineRule: "exact" },  // 32pt
  COMPACT:  { line: 360, lineRule: "exact" },  // 18pt
};

// ─── 缩进（DXA） ─────────────────────────────────────────
const INDENT = {
  FIRST_LINE: 560,  // 首行缩进 2 字符
  BULLET_LEFT: 1120,
  BULLET_HANG: 560,
};

// ─── 边框 ─────────────────────────────────────────────────
const BORDER = {
  NONE:  { style: BorderStyle.NONE, size: 0 },
  THICK: { style: BorderStyle.SINGLE, size: 12, color: "000000" },  // 1.5pt
  THIN:  { style: BorderStyle.SINGLE, size: 6,  color: "000000" },  // 0.75pt
};

// ─── 样式预设 ─────────────────────────────────────────────
function getStyles() {
  return {
    default: {
      document: {
        run: { font: FONT.FANGSONG, size: SIZE.SI_HAO },
        paragraph: { spacing: LINE.BODY },
      },
    },
    paragraphStyles: [
      {
        id: "Heading1", name: "Heading 1",
        basedOn: "Normal", next: "Normal", quickFormat: true,
        run: { font: FONT.HEITI, size: SIZE.SAN_HAO, bold: true },
        paragraph: { spacing: { ...LINE.HEADING1, before: 240, after: 120 }, outlineLevel: 0 },
      },
      {
        id: "Heading2", name: "Heading 2",
        basedOn: "Normal", next: "Normal", quickFormat: true,
        run: { font: FONT.KAITI, size: SIZE.SI_HAO, bold: true },
        paragraph: { spacing: { ...LINE.HEADING2, before: 120, after: 60 }, outlineLevel: 1 },
      },
    ],
  };
}

function getNumbering() {
  return {
    config: [{
      reference: "bullets",
      levels: [{
        level: 0, format: LevelFormat.BULLET, text: "\u2022",
        alignment: AlignmentType.LEFT,
        style: {
          run: { font: FONT.FANGSONG, size: SIZE.SI_HAO },
          paragraph: { indent: { left: INDENT.BULLET_LEFT, hanging: INDENT.BULLET_HANG } },
        },
      }],
    }],
  };
}

// ─── 辅助函数 ─────────────────────────────────────────────

/** 报告标题区（无封面，居中） */
function titleBlock(title, subtitle, date, institution) {
  const items = [];
  items.push(new Paragraph({
    alignment: AlignmentType.CENTER,
    spacing: { ...LINE.TITLE, after: 0 },
    children: [new TextRun({ text: title, font: FONT.HEITI, size: SIZE.SAN_HAO, bold: true })],
  }));
  if (subtitle) {
    items.push(new Paragraph({
      alignment: AlignmentType.CENTER,
      spacing: { ...LINE.TITLE, after: 120 },
      children: [new TextRun({ text: subtitle, font: FONT.HEITI, size: SIZE.SAN_HAO })],
    }));
  }
  items.push(new Paragraph({
    alignment: AlignmentType.CENTER,
    spacing: { ...LINE.BODY, after: 0 },
    children: [new TextRun({ text: date, font: FONT.FANGSONG, size: SIZE.SI_HAO })],
  }));
  if (institution) {
    items.push(new Paragraph({
      alignment: AlignmentType.CENTER,
      spacing: { ...LINE.BODY, after: 240 },
      children: [new TextRun({ text: institution, font: FONT.FANGSONG, size: SIZE.SI_HAO })],
    }));
  }
  return items;
}

/** 一级标题 */
function h1(text) {
  return new Paragraph({
    heading: HeadingLevel.HEADING_1,
    spacing: { ...LINE.HEADING1, before: 240, after: 120 },
    children: [new TextRun({ text, font: FONT.HEITI, size: SIZE.SAN_HAO, bold: true })],
  });
}

/** 二级标题 */
function h2(text) {
  return new Paragraph({
    heading: HeadingLevel.HEADING_2,
    spacing: { ...LINE.HEADING2, before: 120, after: 60 },
    children: [new TextRun({ text, font: FONT.KAITI, size: SIZE.SI_HAO, bold: true })],
  });
}

/** 正文段落 */
function body(text, opts = {}) {
  const { bold = false, align = AlignmentType.JUSTIFIED, indent = true } = opts;
  return new Paragraph({
    alignment: align,
    indent: indent ? { firstLine: INDENT.FIRST_LINE } : undefined,
    spacing: LINE.BODY,
    children: [new TextRun({ text, font: FONT.FANGSONG, size: SIZE.SI_HAO, bold })],
  });
}

/** 多 run 正文段落（支持混排加粗） */
function bodyRuns(runs, opts = {}) {
  const { align = AlignmentType.JUSTIFIED, indent = true } = opts;
  return new Paragraph({
    alignment: align,
    indent: indent ? { firstLine: INDENT.FIRST_LINE } : undefined,
    spacing: LINE.BODY,
    children: runs.map(r => {
      if (typeof r === "string") {
        return new TextRun({ text: r, font: FONT.FANGSONG, size: SIZE.SI_HAO });
      }
      return new TextRun({ font: FONT.FANGSONG, size: SIZE.SI_HAO, ...r });
    }),
  });
}

/** 列表项 */
function bullet(text) {
  return new Paragraph({
    numbering: { reference: "bullets", level: 0 },
    spacing: LINE.BODY,
    children: [new TextRun({ text, font: FONT.FANGSONG, size: SIZE.SI_HAO })],
  });
}

/** 三线表 */
function threeLineTable(headers, rows, opts = {}) {
  const { colWidths } = opts;
  const widths = colWidths || headers.map(() => Math.floor(PAGE.CONTENT_WIDTH / headers.length));

  function cell(text, isHeader, isLastRow, colIdx) {
    const borders = {
      top:    isHeader ? BORDER.THICK : BORDER.NONE,
      bottom: isHeader ? BORDER.THIN : (isLastRow ? BORDER.THICK : BORDER.NONE),
      left:   BORDER.NONE,
      right:  BORDER.NONE,
    };
    return new TableCell({
      borders,
      width: { size: widths[colIdx], type: WidthType.DXA },
      shading: isHeader ? { fill: "1F3864", type: ShadingType.CLEAR } : undefined,
      margins: { top: 40, bottom: 40, left: 80, right: 80 },
      children: [new Paragraph({
        alignment: AlignmentType.CENTER,
        spacing: LINE.TABLE,
        children: [new TextRun({
          text: String(text),
          font: isHeader ? FONT.HEITI : FONT.FANGSONG,
          size: SIZE.XIAO_SI,
          bold: isHeader,
          color: isHeader ? "FFFFFF" : undefined,
        })],
      })],
    });
  }

  // 表级边框全部 NONE，由 cell 级别控制三线效果
  const noBorder = { style: BorderStyle.NONE, size: 0, color: "FFFFFF" };
  return new Table({
    width: { size: PAGE.CONTENT_WIDTH, type: WidthType.DXA },
    columnWidths: widths,
    borders: {
      top: noBorder, bottom: noBorder,
      left: noBorder, right: noBorder,
      insideHorizontal: noBorder, insideVertical: noBorder,
    },
    rows: [
      new TableRow({ children: headers.map((h, i) => cell(h, true, false, i)) }),
      ...rows.map((row, ri) =>
        new TableRow({
          children: row.map((c, ci) => cell(c, false, ri === rows.length - 1, ci)),
        })
      ),
    ],
  });
}

/** 标准页脚（— 页码 —） */
function pageFooter() {
  return new Footer({
    children: [new Paragraph({
      alignment: AlignmentType.CENTER,
      children: [
        new TextRun({ text: "— ", font: FONT.FANGSONG, size: SIZE.WU_HAO }),
        new TextRun({ children: [PageNumber.CURRENT], font: FONT.FANGSONG, size: SIZE.WU_HAO }),
        new TextRun({ text: " —", font: FONT.FANGSONG, size: SIZE.WU_HAO }),
      ],
    })],
  });
}

/** 标准页眉 */
function pageHeader(text = "内部资料  注意保密") {
  return new Header({
    children: [new Paragraph({
      alignment: AlignmentType.CENTER,
      children: [new TextRun({
        text, font: FONT.FANGSONG, size: SIZE.WU_HAO, color: "808080",
      })],
    })],
  });
}

/** section 属性（页面设置） */
function sectionProps(opts = {}) {
  return {
    page: {
      size: { width: PAGE.WIDTH, height: PAGE.HEIGHT },
      margin: {
        top: PAGE.MARGIN_TOP, bottom: PAGE.MARGIN_BOTTOM,
        left: PAGE.MARGIN_LEFT, right: PAGE.MARGIN_RIGHT,
      },
    },
    ...opts,
  };
}

module.exports = {
  PAGE, FONT, SIZE, LINE, INDENT, BORDER,
  getStyles, getNumbering, sectionProps,
  titleBlock, h1, h2, body, bodyRuns, bullet,
  threeLineTable, pageFooter, pageHeader,
};