import { OfficeError } from "../core/errors.ts";

export type StylePreset = "editorial" | "business" | "formal";

export interface MarginsCm {
  top: number;
  bottom: number;
  left: number;
  right: number;
}

export interface WordStyle {
  preset: StylePreset;
  label: string;
  chineseBodyFont: string;
  latinBodyFont: string;
  headingFont: string;
  bodySize: number;
  titleSize: number;
  heading1Size: number;
  heading2Size: number;
  heading3Size: number;
  lineSpacing: number;
  firstLineIndent: number;
  margins: MarginsCm;
  accentColor: string;
  headerFooter: boolean;
}

export interface WordStyleInput {
  chineseBodyFont?: string;
  latinBodyFont?: string;
  headingFont?: string;
  bodySize?: number;
  titleSize?: number;
  heading1Size?: number;
  heading2Size?: number;
  heading3Size?: number;
  lineSpacing?: number;
  firstLineIndent?: number;
  margins?: Partial<MarginsCm>;
  accentColor?: string;
  headerFooter?: boolean;
}

const PRESETS: Record<StylePreset, Omit<WordStyle, "preset">> = {
  editorial: {
    label: "白色编辑风",
    chineseBodyFont: "SimSun",
    latinBodyFont: "Calibri",
    headingFont: "Microsoft YaHei",
    bodySize: 12.5,
    titleSize: 32,
    heading1Size: 26,
    heading2Size: 15,
    heading3Size: 13.5,
    lineSpacing: 1.5,
    firstLineIndent: 0,
    margins: { top: 2.15, bottom: 1.9, left: 2.65, right: 2.65 },
    accentColor: "A63A32",
    headerFooter: true,
  },
  business: {
    label: "商务报告风",
    chineseBodyFont: "Microsoft YaHei",
    latinBodyFont: "Calibri",
    headingFont: "Microsoft YaHei",
    bodySize: 11.5,
    titleSize: 28,
    heading1Size: 20,
    heading2Size: 14,
    heading3Size: 12.5,
    lineSpacing: 1.45,
    firstLineIndent: 0,
    margins: { top: 2.54, bottom: 2.54, left: 2.54, right: 2.54 },
    accentColor: "1F4E79",
    headerFooter: true,
  },
  formal: {
    label: "正式公文/合同风",
    chineseBodyFont: "SimSun",
    latinBodyFont: "Times New Roman",
    headingFont: "SimSun",
    bodySize: 12,
    titleSize: 18,
    heading1Size: 16,
    heading2Size: 14,
    heading3Size: 12,
    lineSpacing: 1.5,
    firstLineIndent: 2,
    margins: { top: 2.54, bottom: 2.54, left: 2.54, right: 2.54 },
    accentColor: "252525",
    headerFooter: false,
  },
};

function cloneStyle(preset: StylePreset): WordStyle {
  const style = PRESETS[preset];
  return { preset, ...style, margins: { ...style.margins } };
}

function requireFont(value: string | undefined, label: string): void {
  if (value !== undefined && !value.trim()) throw new OfficeError(`${label}不能为空。`, "INVALID_STYLE");
}

function requireNumber(value: number | undefined, label: string, minimum: number, maximum: number): void {
  if (value !== undefined && (!Number.isFinite(value) || value < minimum || value > maximum)) {
    throw new OfficeError(`${label}必须介于 ${minimum} 和 ${maximum} 之间。`, "INVALID_STYLE");
  }
}

function requireColor(value: string | undefined): void {
  if (value !== undefined && !/^[0-9A-Fa-f]{6}$/.test(value)) {
    throw new OfficeError("强调色必须是六位十六进制颜色，例如 1F4E79。", "INVALID_STYLE");
  }
}

export function resolveWordStyle(
  documentType: "general" | "report" | "contract" | "news",
  preset?: StylePreset,
  custom?: WordStyleInput,
): WordStyle {
  const basePreset = preset ?? (documentType === "contract" ? "formal" : "editorial");
  const style = cloneStyle(basePreset);
  if (!custom) return style;

  requireFont(custom.chineseBodyFont, "中文正文字体");
  requireFont(custom.latinBodyFont, "英文正文字体");
  requireFont(custom.headingFont, "标题字体");
  requireNumber(custom.bodySize, "正文字号", 8, 24);
  requireNumber(custom.titleSize, "标题字号", 12, 48);
  requireNumber(custom.heading1Size, "一级标题字号", 10, 40);
  requireNumber(custom.heading2Size, "二级标题字号", 9, 32);
  requireNumber(custom.heading3Size, "三级标题字号", 8, 28);
  requireNumber(custom.lineSpacing, "行距倍数", 1, 3);
  requireNumber(custom.firstLineIndent, "首行缩进", 0, 4);
  requireColor(custom.accentColor);
  for (const [edge, value] of Object.entries(custom.margins ?? {})) requireNumber(value, `${edge}页边距`, 0.5, 5);

  return {
    ...style,
    ...(custom.chineseBodyFont !== undefined ? { chineseBodyFont: custom.chineseBodyFont.trim() } : {}),
    ...(custom.latinBodyFont !== undefined ? { latinBodyFont: custom.latinBodyFont.trim() } : {}),
    ...(custom.headingFont !== undefined ? { headingFont: custom.headingFont.trim() } : {}),
    ...(custom.bodySize !== undefined ? { bodySize: custom.bodySize } : {}),
    ...(custom.titleSize !== undefined ? { titleSize: custom.titleSize } : {}),
    ...(custom.heading1Size !== undefined ? { heading1Size: custom.heading1Size } : {}),
    ...(custom.heading2Size !== undefined ? { heading2Size: custom.heading2Size } : {}),
    ...(custom.heading3Size !== undefined ? { heading3Size: custom.heading3Size } : {}),
    ...(custom.lineSpacing !== undefined ? { lineSpacing: custom.lineSpacing } : {}),
    ...(custom.firstLineIndent !== undefined ? { firstLineIndent: custom.firstLineIndent } : {}),
    ...(custom.accentColor !== undefined ? { accentColor: custom.accentColor.toUpperCase() } : {}),
    ...(custom.headerFooter !== undefined ? { headerFooter: custom.headerFooter } : {}),
    margins: { ...style.margins, ...(custom.margins ?? {}) },
  };
}

export const STYLE_PRESET_CHOICES: ReadonlyArray<{ preset: StylePreset; label: string; summary: string }> = [
  { preset: "editorial", label: "白色编辑风", summary: "留白充足、暗红强调，适合文章、说明和新闻稿" },
  { preset: "business", label: "商务报告风", summary: "深蓝强调、清晰层级，适合汇报、方案和周报" },
  { preset: "formal", label: "正式公文/合同风", summary: "宋体为主、保守排版，适合合同、通知和函件" },
];