import { afterAll, beforeAll, describe, expect, it } from 'vitest'
import { InMemoryKVDriver } from '../../src/kv/memory.js'
import type { KVDriver } from '../../src/kv/driver.js'
import { KVStorage } from '../../src/kv/node.js'
import { KVEventStorage } from '../../src/events/kv.js'
import { EventSourcedDocumentStorage } from '../../src/documents/event-sourced.js'
import { createKVHttpHandler } from '../../src/http/handler.js'
import { HttpKVDriver } from '../../src/http/client.js'
import { runKVDriverConformance } from '../../src/testing/kv-conformance.js'
import { collect, CountingDriver, MinimalDriver } from '../helpers.js'
import { serve } from './node-server.js'

/** A client wired straight to a handler, no socket. */
function inProcess(server: KVDriver = new InMemoryKVDriver(), caps?: ConstructorParameters<typeof HttpKVDriver>[0]['capabilities']) {
  const handler = createKVHttpHandler(server, { basePath: '/kv' })
  return new HttpKVDriver({ url: 'http://test/kv', capabilities: caps, fetch: async (input, init) => handler(new Request(input, init)) })
}

runKVDriverConformance('HttpKVDriver (in-process)', () => inProcess())
runKVDriverConformance('HttpKVDriver (minimal server driver, discovered capabilities)', () => {
  const handler = createKVHttpHandler(new MinimalDriver())
  return HttpKVDriver.connect({ url: 'http://test', fetch: async (input, init) => handler(new Request(input, init)) })
})

describe('over a real socket', () => {
  let server: Awaited<ReturnType<typeof serve>>
  const backends: InMemoryKVDriver[] = []
  beforeAll(async () => {
    // One server; each driver gets a fresh backend selected by path.
    server = await serve(async (req) => {
      const m = /^\/db(\d+)/.exec(new URL(req.url).pathname)
      const backend = backends[Number(m?.[1])]
      if (!backend) return new Response('no db', { status: 404 })
      return createKVHttpHandler(backend, { basePath: `/db${m![1]}` })(req)
    })
  })
  afterAll(() => server.close())

  const fresh = () => {
    backends.push(new InMemoryKVDriver())
    return HttpKVDriver.connect({ url: `${server.url}/db${backends.length - 1}` })
  }

  runKVDriverConformance('HttpKVDriver (node:http)', fresh)

  it('cancels a server-side scan when the client stops early', async () => {
    const d = await fresh()
    await d.setMany(Array.from({ length: 5000 }, (_, i) => [`k${String(i).padStart(5, '0')}`, i] as [string, number]))
    const first: string[] = []
    for await (const [k] of d.scan({})) {
      first.push(k)
      if (first.length === 3) break
    }
    expect(first).toEqual(['k00000', 'k00001', 'k00002'])
  })

  it('runs the whole stack (KV indexes, events, documents) over HTTP', async () => {
    const kv = new KVStorage(await fresh(), { indexes: { users: { byAge: (u: { age: number }) => u.age } } })
    await kv.child('users').set('1', { age: 30 })
    expect(await collect(kv.child('users').findBy('byAge', { gte: 18 }))).toEqual([['1', { age: 30 }]])
    const docs = new EventSourcedDocumentStorage(new KVEventStorage(kv), { indexes: { people: [{ fields: ['email'], unique: true }] } })
    const id = await docs.child('people').insert({ email: 'a@x', n: 1 })
    await docs.child('people').update(id, { $inc: { n: 1 } })
    await expect(docs.child('people').insert({ email: 'a@x' })).rejects.toThrow(/Unique/)
    expect(await docs.child('people').findOne({ email: 'a@x' })).toEqual({ key: id, data: { email: 'a@x', n: 2 } })
  })
})

describe('handler', () => {
  it('reports capabilities and rejects unsupported operations with 501', async () => {
    const handler = createKVHttpHandler(new MinimalDriver())
    const caps = await (await handler(new Request('http://x/capabilities'))).json()
    expect(caps).toEqual({ setIfAbsent: false, batch: false, deleteRange: true })
    const res = await handler(new Request('http://x/batch', { method: 'POST', body: JSON.stringify({ ops: [] }) }))
    expect(res.status).toBe(501)
  })

  it('maps driver errors to 500 and unknown routes to 404', async () => {
    const broken = new CountingDriver(new InMemoryKVDriver())
    broken.getMany = () => Promise.reject(new Error('boom'))
    const handler = createKVHttpHandler(broken)
    expect((await handler(new Request('http://x/getMany', { method: 'POST', body: '{"keys":["a"]}' }))).status).toBe(500)
    expect((await handler(new Request('http://x/nope'))).status).toBe(404)
    await expect(inProcess(new MinimalDriver(), { batch: true }).batch!([])).rejects.toThrow(/HTTP 501/)
  })

  it('distinguishes null values from missing keys', async () => {
    const d = inProcess()
    await d.setMany([['n', null]])
    expect(await d.getMany(['n', 'missing'])).toEqual([null, undefined])
  })
})