import { describe, it, expect, vi } from 'vitest'
import { z } from 'zod'
import { validate } from './validate'
import type { Request, Response, NextFunction } from 'express'

const schema = z.object({ name: z.string(), age: z.number() })

function makeReq(body: unknown): Request {
  return { body } as unknown as Request
}

function makeRes() {
  const res = { status: vi.fn(), json: vi.fn() }
  res.status.mockReturnValue(res as unknown as Response)
  return res
}

describe('validate', () => {
  it('calls next() and assigns parsed body on valid input', () => {
    const req = makeReq({ name: 'Su', age: 30 })
    const res = makeRes()
    const next = vi.fn() as unknown as NextFunction

    validate(schema)(req, res as unknown as Response, next)

    expect(next).toHaveBeenCalledOnce()
    expect(req.body).toEqual({ name: 'Su', age: 30 })
    expect(res.status).not.toHaveBeenCalled()
  })

  it('returns 400 with error details on invalid input', () => {
    const req = makeReq({ name: 123 })
    const res = makeRes()
    const next = vi.fn() as unknown as NextFunction

    validate(schema)(req, res as unknown as Response, next)

    expect(res.status).toHaveBeenCalledWith(400)
    expect(res.json).toHaveBeenCalledWith(
      expect.objectContaining({ error: expect.any(String), details: expect.any(Array) })
    )
    expect(next).not.toHaveBeenCalled()
  })

  it('coerces Zod defaults into req.body', () => {
    const schemaWithDefault = z.object({ model: z.string().default('smart-router') })
    const req = makeReq({})
    const res = makeRes()
    const next = vi.fn() as unknown as NextFunction

    validate(schemaWithDefault)(req, res as unknown as Response, next)

    expect(next).toHaveBeenCalledOnce()
    expect((req.body as { model: string }).model).toBe('smart-router')
  })
})