import type { ProjectCreateRequest } from "@/lib/api/types";

// 立项向导 5 步（UX §6.2）。表单状态用字符串/数组，提交时归一为 ProjectCreateRequest。
export interface WizardForm {
  title: string;
  genre: string;
  logline: string;
  sellingPoints: string[];
  structure: string;
  premise: string;
  protagonist: string;
  theme: string;
}

export const WIZARD_STEPS = 5;

// 各步标题（与 WIZARD_STEPS 一一对应）。第 5 步为「确认/概览」：回显已填字段供复核后提交。
export const STEP_TITLES = [
  "书名 + 题材",
  "一句话故事 + 卖点 + 结构",
  "立意 / 总纲",
  "主角 / 金手指",
  "确认与提交",
] as const;

export const emptyWizardForm: WizardForm = {
  title: "",
  genre: "",
  logline: "",
  sellingPoints: [],
  structure: "",
  premise: "",
  protagonist: "",
  theme: "",
};

export const GENRES = ["玄幻", "仙侠", "都市", "科幻", "历史", "悬疑"];
export const STRUCTURES = ["三幕", "故事圈", "雪花"];
export const SELLING_POINT_PRESETS = ["逆袭", "打脸", "系统流", "双男主", "群像"];

// 每一步可否前进：仅第 1 步（书名）必填，其余可空着继续（草稿式立项）。
export function canAdvance(step: number, form: WizardForm): boolean {
  if (step === 1) return form.title.trim().length > 0;
  return true;
}

// 整个向导可否提交：书名必填。
export function canSubmit(form: WizardForm): boolean {
  return form.title.trim().length > 0;
}

export function clampStep(step: number): number {
  if (step < 1) return 1;
  if (step > WIZARD_STEPS) return WIZARD_STEPS;
  return step;
}

// 归一为后端请求体（snake_case，空值落 null/省略）。
export function toCreateRequest(form: WizardForm): ProjectCreateRequest {
  const trim = (s: string): string | null => {
    const v = s.trim();
    return v.length > 0 ? v : null;
  };
  // 立意（premise）与主角/金手指（protagonist）是两个独立输入，但 M1 projects 表只有
  // premise 一个字段 → 合并进 premise，二者各占一段，互不覆盖（QA H1：此前共用同一字段）。
  const premise =
    [trim(form.premise), form.protagonist.trim() ? `主角/金手指：${form.protagonist.trim()}` : null]
      .filter((s): s is string => s !== null)
      .join("\n\n") || null;
  return {
    title: form.title.trim(),
    genre: trim(form.genre),
    logline: trim(form.logline),
    premise,
    theme: trim(form.theme),
    selling_points: form.sellingPoints,
    structure: trim(form.structure),
  };
}