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import type { GitHubOwnerRepo } from '../../shared/github/pull-request-types'

import { commandExecFileAsync } from '../git/runner'

import { parseWslPath } from '../wsl'

import { resolveWithSshG } from '../ssh/config/ssh-g-config-resolution'

import {

gitHubSshConfigHostAlias,

parseGitHubOwnerRepo,

parseGitHubOwnerRepoWithResolvedSshHostname

} from './github-remote-identity-parsing'

/** `indeterminate` means SSH alias expansion failed and must remain retryable. */

export type GitHubOwnerRepoResolution =

| { kind: 'github'; ownerRepo: GitHubOwnerRepo }

| { kind: 'not-github'; cacheWithGitConfigSignature: boolean }

| { kind: 'indeterminate' }

const SSH_HOSTNAME_CACHE_TTL_MS = 60_000

const SSH_HOSTNAME_FAILURE_CACHE_TTL_MS = 5_000

const SSH_HOSTNAME_CACHE_MAX = 256

const SSH_G_TIMEOUT_MS = 5_000

export type SshConfigResolutionContext = {

repoPath: string

connectionId?: string | null

wslDistro?: string

}

type SshHostnameCacheEntry = {

hostname: string | null

resolved: boolean

expiresAt: number

}

const sshHostnameCache = new Map<string, SshHostnameCacheEntry>()

const sshHostnameInFlight = new Map<string, Promise<SshHostnameCacheEntry>>()

/** @internal - tests only */

export function _resetSshHostnameResolutionCache(): void {

sshHostnameCache.clear()

sshHostnameInFlight.clear()

}

function pruneSshHostnameCache(now: number): void {

for (const [key, entry] of sshHostnameCache) {

if (entry.expiresAt <= now) {

sshHostnameCache.delete(key)

}

}

while (sshHostnameCache.size > SSH_HOSTNAME_CACHE_MAX) {

const oldest = sshHostnameCache.keys().next().value

if (oldest === undefined) {

return

}

sshHostnameCache.delete(oldest)

}

}

function sshRuntimeCacheKey(context: SshConfigResolutionContext): string {

if (context.connectionId) {

return `ssh:${context.connectionId}`

}

const distro = context.wslDistro ?? parseWslPath(context.repoPath)?.distro

return `local:${distro?.toLowerCase() ?? 'host'}`

}

function parseSshGHostname(stdout: string): string | null {

for (const line of stdout.split(/\r?\n/)) {

const match = line.match(/^hostname\s+(.+)$/i)

if (match?.[1].trim()) {

return match[1].trim()

}

}

return null

}

async function resolveSshHostnameInRuntime(

host: string,

context: SshConfigResolutionContext

): Promise<string | null> {

if (context.connectionId) {

return null

}

const wslDistro = context.wslDistro ?? parseWslPath(context.repoPath)?.distro

if (!wslDistro) {

return (await resolveWithSshG(host))?.hostname?.trim() || null

}

try {

const { stdout } = await commandExecFileAsync('ssh', ['-G', '--', host], {

cwd: context.repoPath,

timeout: SSH_G_TIMEOUT_MS,

wslDistro

})

return parseSshGHostname(stdout)

} catch {

return null

}

}

/** Resolve OpenSSH Host → HostName in the repository runtime. */

export async function resolveSshConfigHostname(

host: string,

context: SshConfigResolutionContext = { repoPath: '' }

): Promise<{

hostname: string | null

resolved: boolean

}> {

const cacheKey = `${sshRuntimeCacheKey(context)}\0${host}`

const now = Date.now()

pruneSshHostnameCache(now)

const cached = sshHostnameCache.get(cacheKey)

if (cached && cached.expiresAt > now) {

return { hostname: cached.hostname, resolved: cached.resolved }

}

const inFlight = sshHostnameInFlight.get(cacheKey)

if (inFlight) {

const entry = await inFlight

return { hostname: entry.hostname, resolved: entry.resolved }

}

const probe = (async (): Promise<SshHostnameCacheEntry> => {

const hostname = await resolveSshHostnameInRuntime(host, context)

const resolved = hostname != null && hostname.length > 0

const entry: SshHostnameCacheEntry = {

hostname: resolved ? hostname : null,

resolved,

expiresAt:

Date.now() + (resolved ? SSH_HOSTNAME_CACHE_TTL_MS : SSH_HOSTNAME_FAILURE_CACHE_TTL_MS)

}

sshHostnameCache.set(cacheKey, entry)

pruneSshHostnameCache(Date.now())

return entry

})()

sshHostnameInFlight.set(cacheKey, probe)

try {

const entry = await probe

return { hostname: entry.hostname, resolved: entry.resolved }

} finally {

if (sshHostnameInFlight.get(cacheKey) === probe) {

sshHostnameInFlight.delete(cacheKey)

}

}

}

/** Resolve github.com identity without rewriting the Git transport URL. */

export async function classifyGitHubOwnerRepoFromRemoteUrl(

remoteUrl: string,

context: SshConfigResolutionContext = { repoPath: '' }

): Promise<GitHubOwnerRepoResolution> {

const direct = parseGitHubOwnerRepo(remoteUrl)

if (direct) {

return { kind: 'github', ownerRepo: direct }

}

const aliasHost = gitHubSshConfigHostAlias(remoteUrl)

if (!aliasHost) {

return { kind: 'not-github', cacheWithGitConfigSignature: true }

}

const { hostname, resolved } = await resolveSshConfigHostname(aliasHost, context)

if (!resolved || !hostname) {

return { kind: 'indeterminate' }

}

const ownerRepo = parseGitHubOwnerRepoWithResolvedSshHostname(remoteUrl, hostname)

return ownerRepo

? { kind: 'github', ownerRepo }

: { kind: 'not-github', cacheWithGitConfigSignature: false }

}

/** Convenience wrapper for callers that only need owner/repo or null. */

export async function resolveGitHubOwnerRepoFromRemoteUrl(

remoteUrl: string,

context: SshConfigResolutionContext = { repoPath: '' }

): Promise<GitHubOwnerRepo | null> {

const result = await classifyGitHubOwnerRepoFromRemoteUrl(remoteUrl, context)

return result.kind === 'github' ? result.ownerRepo : null

}