/**
 * registry.legacy-monolith / registry.mixed-layout guard — an aggregate that
 * registers pages of its OWN is a legacy MCP-era monolith (or a hand edit).
 * Before this guard, running the aggregator on such an app overwrote the
 * monolith with an EMPTY aggregate: every page unregistered, blank app (the
 * PickEBike incident). The guard fail-closes with the migration path; only
 * split-component-registry's in-process re-aggregation may override it.
 */
import { describe, it, expect, beforeEach, afterEach } from 'vitest'
import fs from 'node:fs'
import os from 'node:os'
import path from 'node:path'
import { generate } from '../generate.js'

let web: string

beforeEach(() => {
  web = fs.mkdtempSync(path.join(os.tmpdir(), 'agg-guard-'))
})

afterEach(() => {
  fs.rmSync(web, { recursive: true, force: true })
})

function write(rel: string, content: string): void {
  const abs = path.join(web, rel)
  fs.mkdirSync(path.dirname(abs), { recursive: true })
  fs.writeFileSync(abs, content)
}

const MONOLITH = `// Auto-generated by SmartStack MCP
import { lazy } from 'react';
import { PageRegistry } from '@atlashub/smartstack';
PageRegistry.register('fleet.bikes', lazy(() => import('@/pages/fleet/bikes/FleetBikeListPage')));
PageRegistry.register('fleet.bikes.detail', lazy(() => import('@/pages/fleet/bikes/FleetBikeDetailPage')));
`

const PER_MODULE = `import { PageRegistry, lazyWithRetry } from '@atlashub/smartstack';
const BikesListPage = lazyWithRetry(() => import('@/pages/fleet/bikes/BikesListPage'));
PageRegistry.register('fleet.bikes2', BikesListPage);
`

describe('aggregate-component-registry — legacy/mixed layout guard', () => {
  it('legacy-monolith: aggregate with own registers + zero per-module → hard error, nothing emitted', () => {
    write('src/extensions/componentRegistry.generated.ts', MONOLITH)
    const res = generate({ projectPath: web, exclude: [] })
    expect(res.errors).toHaveLength(1)
    expect(res.errors[0]).toContain('registry.legacy-monolith')
    expect(res.errors[0]).toContain('split-component-registry')
    expect(res.files).toEqual([])
    // the monolith on disk is untouched (generate is pure — but assert the intent)
    expect(fs.readFileSync(path.join(web, 'src/extensions/componentRegistry.generated.ts'), 'utf-8')).toBe(MONOLITH)
  })

  it('mixed: aggregate with own registers WHILE a per-module registry exists → registry.mixed-layout', () => {
    write('src/extensions/componentRegistry.generated.ts', MONOLITH)
    write('src/pages/fleet/bikes/BikesListPage.tsx', 'export default () => null\n')
    write('src/extensions/fleet-bikesRegistry.ts', PER_MODULE)
    const res = generate({ projectPath: web, exclude: [] })
    expect(res.errors).toHaveLength(1)
    expect(res.errors[0]).toContain('registry.mixed-layout')
    expect(res.files).toEqual([])
  })

  it('overwriteLegacyAggregate: true (split-component-registry re-aggregation) bypasses the guard', () => {
    write('src/extensions/componentRegistry.generated.ts', MONOLITH)
    write('src/pages/fleet/bikes/BikesListPage.tsx', 'export default () => null\n')
    write('src/extensions/fleet-bikesRegistry.ts', PER_MODULE)
    const res = generate({ projectPath: web, exclude: [], overwriteLegacyAggregate: true })
    expect(res.errors).toEqual([])
    const content = res.files.find((f) => f.path.endsWith('componentRegistry.generated.ts'))?.content
    expect(content).toContain(`import './fleet-bikesRegistry';`)
  })

  it('a CLEAN aggregate (side-effect imports only) + zero candidates keeps the current behaviour (fresh app)', () => {
    write(
      'src/extensions/componentRegistry.generated.ts',
      `// componentRegistry.generated.ts\nimport './oldRegistry';\n`,
    )
    const res = generate({ projectPath: web, exclude: [] })
    expect(res.errors).toEqual([])
    expect(res.files.length).toBeGreaterThan(0)
  })

  it('no aggregate on disk at all — guard is inert', () => {
    write('src/pages/fleet/bikes/BikesListPage.tsx', 'export default () => null\n')
    write('src/extensions/fleet-bikesRegistry.ts', PER_MODULE)
    const res = generate({ projectPath: web, exclude: [] })
    expect(res.errors).toEqual([])
    expect(res.parsed.map((p) => p.module)).toEqual(['fleet-bikes'])
  })
})