import fs from 'node:fs'
import os from 'node:os'
import path from 'node:path'

import { expect, test } from '@jest/globals'
import type { FetchFromRegistry } from '@pnpm/fetching.types'

import { resolveNodeRuntime } from '../lib/index.js'

const MIRROR = 'https://node.example/download/rc/'

const fetch: FetchFromRegistry = async (url) => {
  switch (url) {
    case `${MIRROR}index.json`:
      return new Response(JSON.stringify([
        { version: 'v22.11.0', lts: false },
        { version: 'v22.10.0', lts: false },
      ]))
    case `${MIRROR}v22.11.0/SHASUMS256.txt`:
      return new Response('ed52239294ad517fbe91a268146d5d2aa8a17d2d62d64873e43219078ba71c4e  node-v22.11.0-linux-x64.tar.gz\n')
    default:
      throw new Error(`Unexpected URL: ${url}`)
  }
}

test.each([
  ['runtime:rc/22', undefined, 'runtime:22.11.0'],
  ['runtime:rc/^22', undefined, 'runtime:^22.11.0'],
  ['runtime:rc/22', 'runtime:~22.0.0', 'runtime:~22.11.0'],
  ['runtime:rc/^22', 'runtime:22.0.0', 'runtime:22.11.0'],
])('resolveNodeRuntime() preserves runtime version prefix (%s, previous %s)', async (bareSpecifier, prevSpecifier, expected) => {
  const resolution = await resolveNodeRuntime({
    fetchFromRegistry: fetch,
    nodeDownloadMirrors: {
      rc: MIRROR,
    },
  }, {
    alias: 'node',
    bareSpecifier,
    prevSpecifier,
  })

  expect(resolution?.normalizedBareSpecifier).toBe(expected)
})

const RELEASE_MIRROR = 'https://node.example/download/release/'

// An exact-specifier resolve skips the release index, so a nonexistent
// version first fails its asset fetch; the resolver must then consult the
// index and raise the canonical not-found error rather than the raw fetch
// failure.
test('resolveNodeRuntime() raises NODEJS_VERSION_NOT_FOUND for a nonexistent exact version', async () => {
  const { fetch: countedFetch, calls } = countingFetch({
    [`${RELEASE_MIRROR}index.json`]: () => new Response(JSON.stringify([{ version: 'v22.11.0', lts: false }])),
  })

  await expect(resolveNodeRuntime({
    fetchFromRegistry: countedFetch,
    nodeDownloadMirrors: { release: RELEASE_MIRROR },
  }, {
    alias: 'node',
    bareSpecifier: 'runtime:22.99.0',
  })).rejects.toThrow(/Could not find a Node.js version that satisfies 22.99.0/)
  // The asset fetch runs first; the index is only consulted to classify the
  // failure.
  expect(calls[0]).toBe(`${RELEASE_MIRROR}v22.99.0/SHASUMS256.txt`)
  expect(calls).toContain(`${RELEASE_MIRROR}index.json`)
})

// When the index confirms the exact version exists, the asset-fetch failure
// is the real error and must surface unchanged.
test('resolveNodeRuntime() keeps the asset error when the exact version exists', async () => {
  const { fetch: countedFetch } = countingFetch({
    [`${RELEASE_MIRROR}index.json`]: () => new Response(JSON.stringify([{ version: 'v22.11.0', lts: false }])),
    [`${RELEASE_MIRROR}v22.11.0/SHASUMS256.txt`]: () => new Response(null, { status: 500 }),
  })

  await expect(resolveNodeRuntime({
    fetchFromRegistry: countedFetch,
    nodeDownloadMirrors: { release: RELEASE_MIRROR },
  }, {
    alias: 'node',
    bareSpecifier: 'runtime:22.11.0',
  })).rejects.toThrow(/SHASUMS256.txt/)
})

// A SHASUMS body cached by an earlier resolve serves the next one without
// refetching it; only the (mutable) release index is fetched again.
test('resolveNodeRuntime() serves repeat asset reads from the cache', async () => {
  const cacheDir = await fs.promises.mkdtemp(path.join(os.tmpdir(), 'pnpm-node-resolver-'))
  try {
    const { fetch: countedFetch, calls } = countingFetch({
      [`${MIRROR}index.json`]: () => new Response(JSON.stringify([{ version: 'v22.11.0', lts: false }])),
      [`${MIRROR}v22.11.0/SHASUMS256.txt`]: () => new Response('ed52239294ad517fbe91a268146d5d2aa8a17d2d62d64873e43219078ba71c4e  node-v22.11.0-linux-x64.tar.gz\n'),
    })

    for (let run = 0; run < 2; run++) {
      // eslint-disable-next-line no-await-in-loop
      const resolution = await resolveNodeRuntime({
        fetchFromRegistry: countedFetch,
        nodeDownloadMirrors: { rc: MIRROR },
        cacheDir,
      }, {
        alias: 'node',
        bareSpecifier: 'runtime:rc/22',
      })
      expect(resolution?.resolution.variants).toHaveLength(1)
    }

    expect(calls.filter((url) => url === `${MIRROR}v22.11.0/SHASUMS256.txt`)).toHaveLength(1)
    expect(calls.filter((url) => url === `${MIRROR}index.json`)).toHaveLength(2)
  } finally {
    await fs.promises.rm(cacheDir, { recursive: true, force: true })
  }
})

function countingFetch (responses: Record<string, () => Response>): { fetch: FetchFromRegistry, calls: string[] } {
  const calls: string[] = []
  const countedFetch = (async (url: string) => {
    calls.push(url)
    const response = responses[url]
    if (!response) return new Response(null, { status: 404 })
    return response()
  }) as unknown as FetchFromRegistry
  return { fetch: countedFetch, calls }
}