/**

* @file Git helpers for the lockstep harness. Thin wrappers over `git -C <dir>

* <cmd>` that the kind checkers (file-fork, version-pin) use to peek at

* submodule state without dragging in a full libgit binding. The harness is

* read-only — these helpers never mutate. `splitLines` is the CRLF-tolerant

* counterpart to `.split('\n')`; bare splits leave a trailing `\r` on each

* line when git is invoked on Windows / msys, which throws off downstream

* `includes`/match checks. `resolveUpstream` is a lookup helper that lives

* here because it's coupled to the same per-row-message accumulator the other

* helpers write to.

*/

import { spawnSync } from '@socketsecurity/lib-stable/process/spawn/child'

import type { Upstream } from './schema.mts'

import type { DriftCommit, Manifest } from './types.mts'

/**

* Split text on LF after CRLF normalization. Git on Windows / msys may emit

* CRLF-terminated output; bare `.split('\n')` leaves a trailing `\r` on every

* line that throws off downstream `includes`/match checks.

*/

export function splitLines(text: string): string[] {

return text.replace(/\r\n/g, '\n').split(/\r?\n/)

}

export function gitIn(submoduleDir: string, args: string[]): string {

const result = spawnSync('git', ['-C', submoduleDir, ...args], {

stdio: ['ignore', 'pipe', 'pipe'],

stdioString: true,

})

if (result.error) {

throw result.error

}

if (result.status !== 0) {

throw new Error(

`git ${args.join(' ')} failed (status ${result.status}): ${result.stderr.trim()}`,

)

}

return result.stdout

}

export function shaIsReachable(submoduleDir: string, sha: string): boolean {

try {

gitIn(submoduleDir, ['cat-file', '-e', sha])

return true

} catch {

return false

}

}

export function driftCommitsSince(

submoduleDir: string,

sha: string,

pathInRepo: string,

): DriftCommit[] {

try {

const out = gitIn(submoduleDir, [

'log',

'--pretty=format:%H%x09%s',

`${sha}..HEAD`,

'--',

pathInRepo,

])

const trimmed = out.trim()

if (!trimmed) {

return []

}

return splitLines(trimmed).map(line => {

// Preserve any embedded tabs in the commit subject (rare but

// possible) — `.split` destructuring would truncate at the

// first tab inside the summary.

const [commitSha, ...summaryParts] = line.split('\t')

return {

sha: commitSha ?? '',

summary: summaryParts.join('\t') ?? '',

}

})

} catch {

return []

}

}

export function resolveUpstream(

manifest: Manifest,

alias: string,

messages: string[],

): Upstream | undefined {

const upstream = manifest.upstreams?.[alias]

if (!upstream) {

const known = Object.keys(manifest.upstreams ?? {}).join(', ') || '(none)'

messages.push(`unknown upstream alias '${alias}' (known: ${known})`)

return undefined

}

return upstream

}