import type { FckByMember, Material } from './rebar/common';
import type { PierInput } from './types';

/** Project file schema (spec §8). Bump only with a migration. */
export const SCHEMA_VERSION = 1;

export interface ProjectInfo {
  name: string;
  bridge: string;
  client: string;
  author: string;
  crs: string;
  memo: string;
}

export interface ProjectPier {
  id: string;
  /** Generated input: the values the 3D model was built from. The model is not stored; it is regenerated on open (spec §8). */
  input: PierInput;
  /** Values as imported from the sheet (기본값). Missing in files saved before change tracking: input is used. */
  defaults?: PierInput;
  /** Values currently in the cards (현재 입력). Missing in older files: input is used. */
  draft?: PierInput;
}

export interface ProjectFile {
  schemaVersion: number;
  project: ProjectInfo;
  source: { fileName: string; sheets: string[] };
  piers: ProjectPier[];
  history: { version: string; note: string; at: string }[];
  /** ③ 공통 설정 (fck · fy). Absent in older files: the defaults are used. */
  common?: Material;
  /** ② 부재별 fck (MPa). Absent in older files: every member uses the 공통 fck. */
  fckByMember?: FckByMember;
}

/** Serialises a project to the pretty-printed JSON stored in <교량명>_교각설계.pzr.json. */
export function serializeProject(p: ProjectFile): string {
  return `${JSON.stringify(p, null, 2)}\n`;
}

/**
 * Parses and checks a project file. Throws with a message that names the first problem, so a damaged file is
 * refused instead of being half-loaded.
 */
export function parseProject(text: string): ProjectFile {
  let raw: unknown;
  try {
    raw = JSON.parse(text);
  } catch {
    throw new Error('프로젝트 파일이 JSON으로 읽히지 않습니다.');
  }
  const obj = raw as Partial<ProjectFile>;
  if (!obj || typeof obj !== 'object') throw new Error('프로젝트 파일 형식이 아닙니다.');
  if (obj.schemaVersion !== SCHEMA_VERSION) {
    throw new Error(`지원하지 않는 파일 버전입니다 (schemaVersion ${String(obj.schemaVersion)}, 지원: ${SCHEMA_VERSION}).`);
  }
  if (!Array.isArray(obj.piers)) throw new Error('piers 목록이 없습니다.');
  if (obj.fckByMember !== undefined) {
    for (const [member, value] of Object.entries(obj.fckByMember)) {
      if (!['column', 'coping', 'footing'].includes(member) || typeof value !== 'number' || !(value > 0)) {
        throw new Error(`부재별 fck 값이 맞지 않습니다 (${member}: ${String(value)}).`);
      }
    }
  }
  obj.piers.forEach((p, i) => {
    if (!p || typeof p.id !== 'string' || !p.input) throw new Error(`교각 ${i + 1}: id 또는 input이 없습니다.`);
    const input = p.input;
    if (typeof input.name !== 'string' || !Array.isArray(input.ips) || !Array.isArray(input.bearings)) {
      throw new Error(`교각 ${i + 1}(${String(input.name)}): 입력 형식이 맞지 않습니다.`);
    }
    for (const extra of [p.defaults, p.draft]) {
      if (extra !== undefined && (typeof extra !== 'object' || extra === null || typeof extra.name !== 'string')) {
        throw new Error(`교각 ${i + 1}(${input.name}): defaults 또는 draft 형식이 맞지 않습니다.`);
      }
    }
  });
  return obj as ProjectFile;
}