#!/usr/bin/env bun
import { existsSync, mkdirSync, writeFileSync } from 'node:fs';
import { join } from 'node:path';

const name = process.argv[2];

if (!name) {
  process.stderr.write('Usage: bun run scaffold:entity <name>\n');
  process.stderr.write('  name: kebab-case entity name (e.g. financial-record)\n');
  process.exit(1);
}

if (!/^[a-z][a-z0-9]*(-[a-z][a-z0-9]*)*$/.test(name)) {
  process.stderr.write(`Invalid entity name "${name}". Use kebab-case (e.g. financial-record).\n`);
  process.exit(1);
}

const src = new URL('../src', import.meta.url).pathname;
const entityDir = join(src, 'entities', name);

if (existsSync(entityDir)) {
  process.stderr.write(`Entity "${name}" already exists at ${entityDir}\n`);
  process.exit(1);
}

// Derive naming variants
const pascal = name
  .split('-')
  .map((s) => s[0]!.toUpperCase() + s.slice(1))
  .join('');
const upper = name.toUpperCase().replace(/-/g, '_');
const camel = name
  .split('-')
  .map((s, i) => (i === 0 ? s : s[0]!.toUpperCase() + s.slice(1)))
  .join('');
const tableName = name.replace(/-/g, '_') + 's';
const migrationId = `${new Date().toISOString().slice(0, 10)}_${name.replace(/-/g, '_')}_initial`;

const types = `\
export const ${upper}_STATUSES = ['active', 'archived'] as const;
export type ${pascal}Status = (typeof ${upper}_STATUSES)[number];

export interface ${pascal} {
  readonly id: number;
  readonly name: string;
  readonly status: ${pascal}Status;
  readonly note: string;
  readonly createdAt: string;
  readonly updatedAt: string;
}

export interface ${pascal}Draft {
  readonly name: string;
  readonly status?: ${pascal}Status;
  readonly note?: string;
}

export type ${pascal}Patch = Partial<${pascal}Draft>;
`;

const schema = `\
import type { Db, Migration } from '@/shared/db';

import { ${upper}_STATUSES } from './types';

const statusCheck = ${upper}_STATUSES.map((s) => \`'\${s}'\`).join(', ');

export const ${camel}Migrations: readonly Migration[] = [
  {
    id: '${migrationId}',
    up(db: Db): void {
      db.exec(\`
        CREATE TABLE IF NOT EXISTS ${tableName} (
          id         INTEGER PRIMARY KEY AUTOINCREMENT,
          name       TEXT    NOT NULL,
          status     TEXT    NOT NULL DEFAULT 'active',
          note       TEXT    NOT NULL DEFAULT '',
          created_at TEXT    NOT NULL DEFAULT (datetime('now')),
          updated_at TEXT    NOT NULL DEFAULT (datetime('now')),
          CHECK (status IN (\${statusCheck}))
        );
        CREATE INDEX IF NOT EXISTS idx_${tableName}_status ON ${tableName}(status);
      \`);
    },
  },
];
`;

const repo = `\
import type { Db } from '@/shared/db';
import { notFound } from '@/shared/http/errors';

import type { ${pascal}, ${pascal}Draft, ${pascal}Patch, ${pascal}Status } from './types';

interface Row {
  id: number;
  name: string;
  status: ${pascal}Status;
  note: string;
  created_at: string;
  updated_at: string;
}

const hydrate = (r: Row): ${pascal} => ({
  id: r.id,
  name: r.name,
  status: r.status,
  note: r.note,
  createdAt: r.created_at,
  updatedAt: r.updated_at,
});

export function list${pascal}s(db: Db, filter?: { status?: ${pascal}Status }): readonly ${pascal}[] {
  const rows = filter?.status
    ? db.prepare('SELECT * FROM ${tableName} WHERE status = ? ORDER BY updated_at DESC').all(filter.status)
    : db.prepare('SELECT * FROM ${tableName} ORDER BY updated_at DESC').all();
  return (rows as Row[]).map(hydrate);
}

export function get${pascal}(db: Db, id: number): ${pascal} {
  const row = db.prepare('SELECT * FROM ${tableName} WHERE id = ?').get(id) as Row | undefined;
  if (!row) throw notFound('${camel}_not_found', \`${name} \${id} not found\`);
  return hydrate(row);
}

export function create${pascal}(db: Db, draft: ${pascal}Draft): ${pascal} {
  const result = db
    .prepare(
      \`INSERT INTO ${tableName} (name, status, note) VALUES (?, ?, ?)\`,
    )
    .run(draft.name, draft.status ?? 'active', draft.note ?? '');
  return get${pascal}(db, Number(result.lastInsertRowid));
}

export function update${pascal}(db: Db, id: number, patch: ${pascal}Patch): ${pascal} {
  const current = get${pascal}(db, id);
  const next = { ...current, ...patch };
  db.prepare(
    \`UPDATE ${tableName}
       SET name = ?, status = ?, note = ?, updated_at = datetime('now')
     WHERE id = ?\`,
  ).run(next.name, next.status, next.note, id);
  return get${pascal}(db, id);
}

export function delete${pascal}(db: Db, id: number): void {
  const result = db.prepare('DELETE FROM ${tableName} WHERE id = ?').run(id);
  if (result.changes === 0) throw notFound('${camel}_not_found', \`${name} \${id} not found\`);
}
`;

const barrel = `\
export type { ${pascal}, ${pascal}Draft, ${pascal}Patch, ${pascal}Status } from './types';
export { ${upper}_STATUSES } from './types';
export { ${camel}Migrations } from './schema';
export { create${pascal}, delete${pascal}, get${pascal}, list${pascal}s, update${pascal} } from './repo';
`;

mkdirSync(entityDir, { recursive: true });
writeFileSync(join(entityDir, 'types.ts'), types);
writeFileSync(join(entityDir, 'schema.ts'), schema);
writeFileSync(join(entityDir, 'repo.ts'), repo);
writeFileSync(join(entityDir, 'index.ts'), barrel);

const out = [
  `Scaffolded entity "${name}" at src/entities/${name}/`,
  `  types.ts  — ${pascal}, ${pascal}Draft, ${pascal}Patch, ${pascal}Status`,
  `  schema.ts — ${camel}Migrations (migration: ${migrationId})`,
  `  repo.ts   — list/get/create/update/delete`,
  `  index.ts  — barrel`,
  '',
  'Next steps:',
  `  1. Implement the schema/types for your real domain model`,
  `  2. Mount in src/surfaces/<surface>/<entity>.ts`,
  `  3. Add ${camel}Migrations to src/app/server.ts runMigrations call`,
  '',
].join('\n');

process.stdout.write(out);