import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest'
import { apiFetch, apiFetchVoid, AuthError, APIError } from './client'
import { tokenStore } from '../lib/auth'

// ── Helpers ──────────────────────────────────────────────────────────────────

function makeOkResponse(body: unknown = {}, status = 200): Response {
  return {
    ok: true,
    status,
    headers: { get: () => null },
    json: () => Promise.resolve(body),
  } as unknown as Response
}

function makeErrorResponse(status: number, contentType?: string, body?: unknown): Response {
  return {
    ok: false,
    status,
    headers: {
      get: (h: string) => h.toLowerCase() === 'content-type' ? (contentType ?? null) : null,
    },
    json: () => Promise.resolve(body),
  } as unknown as Response
}

// ── Setup / teardown ─────────────────────────────────────────────────────────

let fetchSpy: ReturnType<typeof vi.fn>

beforeEach(() => {
  fetchSpy = vi.fn()
  vi.stubGlobal('fetch', fetchSpy)
  tokenStore.set(null)
})

afterEach(() => {
  tokenStore.set(null)
  vi.unstubAllGlobals()
  vi.restoreAllMocks()
})

// ── apiFetch: Authorization header behavior ──────────────────────────────────

describe('apiFetch Authorization header', () => {
  it('no stored token → fetch called without Authorization header', async () => {
    fetchSpy.mockResolvedValue(makeOkResponse({ result: 1 }))

    await apiFetch('/api/v1/test')

    const [, init] = fetchSpy.mock.calls[0] as [string, RequestInit]
    const headers = init.headers as Record<string, string>
    expect(headers['Authorization']).toBeUndefined()
  })

  it('stored token → fetch called with Authorization: Bearer <token>', async () => {
    fetchSpy.mockResolvedValue(makeOkResponse({ result: 1 }))
    tokenStore.set('abc')

    await apiFetch('/api/v1/test')

    const [, init] = fetchSpy.mock.calls[0] as [string, RequestInit]
    const headers = init.headers as Record<string, string>
    expect(headers['Authorization']).toBe('Bearer abc')
  })

  it('caller-supplied Authorization header wins over stored token', async () => {
    fetchSpy.mockResolvedValue(makeOkResponse({ result: 1 }))
    tokenStore.set('stored-token')

    await apiFetch('/api/v1/test', {
      headers: { Authorization: 'Bearer caller-token' },
    })

    const [, init] = fetchSpy.mock.calls[0] as [string, RequestInit]
    const headers = init.headers as Record<string, string>
    expect(headers['Authorization']).toBe('Bearer caller-token')
  })

  it('401 → AuthError thrown (regression)', async () => {
    fetchSpy.mockResolvedValue(makeErrorResponse(401))

    await expect(apiFetch('/api/v1/test')).rejects.toThrow(AuthError)
  })

  it('500 → APIError thrown (regression)', async () => {
    fetchSpy.mockResolvedValue(makeErrorResponse(500))

    await expect(apiFetch('/api/v1/test')).rejects.toThrow(APIError)
  })
})

// ── apiFetchVoid: Authorization header behavior ──────────────────────────────

describe('apiFetchVoid Authorization header', () => {
  it('no stored token → fetch called without Authorization header', async () => {
    fetchSpy.mockResolvedValue(makeOkResponse(undefined, 204))

    await apiFetchVoid('/api/v1/test')

    const [, init] = fetchSpy.mock.calls[0] as [string, RequestInit]
    const headers = init.headers as Record<string, string>
    expect(headers['Authorization']).toBeUndefined()
  })

  it('stored token → fetch called with Authorization: Bearer <token>', async () => {
    fetchSpy.mockResolvedValue(makeOkResponse(undefined, 204))
    tokenStore.set('xyz')

    await apiFetchVoid('/api/v1/test')

    const [, init] = fetchSpy.mock.calls[0] as [string, RequestInit]
    const headers = init.headers as Record<string, string>
    expect(headers['Authorization']).toBe('Bearer xyz')
  })

  it('caller-supplied Authorization header wins over stored token', async () => {
    fetchSpy.mockResolvedValue(makeOkResponse(undefined, 204))
    tokenStore.set('stored-token')

    await apiFetchVoid('/api/v1/test', {
      headers: { Authorization: 'Bearer caller-token' },
    })

    const [, init] = fetchSpy.mock.calls[0] as [string, RequestInit]
    const headers = init.headers as Record<string, string>
    expect(headers['Authorization']).toBe('Bearer caller-token')
  })

  it('401 → AuthError thrown (regression)', async () => {
    fetchSpy.mockResolvedValue(makeErrorResponse(401))

    await expect(apiFetchVoid('/api/v1/test')).rejects.toThrow(AuthError)
  })
})