import type { ImageTemplate } from "@/lib/types";

type ImageTemplateBody = {
  name?: unknown;
  description?: unknown;
  prompt?: unknown;
  previewImageUrl?: unknown;
  settings?: unknown;
  sortOrder?: unknown;
};

type ImageTemplatePatch = Partial<Omit<ImageTemplate, "id" | "ownerId" | "createdAt" | "updatedAt">>;

export function normalizeImageTemplateCreate(body: ImageTemplateBody): Omit<ImageTemplate, "id" | "ownerId" | "createdAt" | "updatedAt"> {
  return {
    name: requiredText(body.name, "模板名称", 80),
    description: optionalText(body.description, 240),
    prompt: requiredText(body.prompt, "预设提示词", 4000),
    previewImageUrl: optionalPreviewUrl(body.previewImageUrl),
    settings: normalizeTemplateSettings(body.settings),
    sortOrder: optionalNumber(body.sortOrder) ?? 0
  };
}

export function normalizeImageTemplateUpdate(body: ImageTemplateBody): ImageTemplatePatch {
  const patch: ImageTemplatePatch = {};
  if ("name" in body) patch.name = requiredText(body.name, "模板名称", 80);
  if ("description" in body) patch.description = optionalText(body.description, 240);
  if ("prompt" in body) patch.prompt = requiredText(body.prompt, "预设提示词", 4000);
  if ("previewImageUrl" in body) patch.previewImageUrl = optionalPreviewUrl(body.previewImageUrl);
  if ("settings" in body) patch.settings = normalizeTemplateSettings(body.settings);
  if ("sortOrder" in body) patch.sortOrder = optionalNumber(body.sortOrder) ?? 0;
  return patch;
}

function requiredText(value: unknown, label: string, maxLength: number): string {
  const text = optionalText(value, maxLength);
  if (!text) throw new Error(`${label}不能为空`);
  return text;
}

function optionalText(value: unknown, maxLength: number): string | undefined {
  if (value === undefined || value === null) return undefined;
  const text = String(value).trim();
  if (!text) return undefined;
  return text.slice(0, maxLength);
}

function optionalPreviewUrl(value: unknown): string | undefined {
  const url = optionalText(value, 1000);
  if (!url) return undefined;
  if (url.startsWith("/") || /^https?:\/\//i.test(url)) return url;
  throw new Error("效果预览图地址必须是 http(s) 或站内路径");
}

function normalizeTemplateSettings(value: unknown): ImageTemplate["settings"] {
  if (!isRecord(value)) return {};
  const width = optionalPositiveInteger(value.width);
  const height = optionalPositiveInteger(value.height);
  const engine = normalizeImageEngine(value.engine);
  const scale = optionalScale(value.scale);
  const quality = normalizeQuality(value.quality);
  return {
    ...(engine ? { engine } : {}),
    ...(width && height ? { width, height } : {}),
    ...(typeof value.forceSingle === "boolean" ? { forceSingle: value.forceSingle } : {}),
    ...(scale !== undefined ? { scale } : {}),
    ...(quality ? { quality } : {})
  };
}

function optionalNumber(value: unknown): number | undefined {
  if (value === undefined || value === null || value === "") return undefined;
  const parsed = Number(value);
  return Number.isFinite(parsed) ? Math.trunc(parsed) : undefined;
}

function optionalPositiveInteger(value: unknown): number | undefined {
  const parsed = optionalNumber(value);
  if (!parsed || parsed < 1) return undefined;
  return Math.min(parsed, 8192);
}

function optionalScale(value: unknown): number | undefined {
  const parsed = optionalNumber(value);
  if (parsed === undefined) return undefined;
  return Math.max(1, Math.min(100, parsed));
}

function normalizeImageEngine(value: unknown): ImageTemplate["settings"]["engine"] | undefined {
  const text = optionalText(value, 20);
  if (text === "jimeng" || text === "evolink" || text === "bailian") return text;
  return undefined;
}

function normalizeQuality(value: unknown): ImageTemplate["settings"]["quality"] | undefined {
  const text = optionalText(value, 20);
  if (text === "low" || text === "medium" || text === "high") return text;
  return undefined;
}

function isRecord(value: unknown): value is Record<string, unknown> {
  return typeof value === "object" && value !== null && !Array.isArray(value);
}