orca/src/shared/branch-name-from-work.ts

import { MARINE_CREATURES } from './marine-creatures'

// Why: the work-derived branch name stays short on purpose — long, sentence-like
// branches read worse than the creature name they replace. Two-to-four words is
// the sweet spot the feature targets.
export const MAX_BRANCH_NAME_WORDS = 4
const MIN_BRANCH_NAME_WORDS = 2

const CREATURE_NAMES_LOWER = new Set(MARINE_CREATURES.map((name) => name.toLowerCase()))

function normalizeName(name: string): string {
  return name.trim().toLowerCase()
}

/**
 * True when `branchLeaf` (the segment after any `prefix/`) is an Orca
 * auto-generated creature name, e.g. `Nautilus` or `Octopus-2`. Used as the
 * eligibility gate so auto-rename only ever overwrites a name Orca itself
 * picked — never a branch the user named deliberately.
 */
export function isAutoGeneratedCreatureBranchName(branchLeaf: string): boolean {
  const normalized = normalizeName(branchLeaf)
  if (!normalized) {
    return false
  }
  // Collision suffixes (`-2`, `-3`, …) are appended at creation; strip one
  // before checking membership so numbered creatures still qualify.
  const base = normalized.replace(/-\d+$/, '')
  return CREATURE_NAMES_LOWER.has(base)
}

/**
 * Turn raw model output into a safe, short kebab-case branch leaf. Returns ''
 * when nothing usable remains, which callers treat as "skip the rename".
 */
export function sanitizeBranchSlug(raw: string, maxWords = MAX_BRANCH_NAME_WORDS): string {
  const words = raw
    .toLowerCase()
    .replace(/[^a-z0-9]+/g, '-')
    .split('-')
    .filter(Boolean)
  if (words.length === 0) {
    return ''
  }
  return words.slice(0, maxWords).join('-')
}

/**
 * Drop a leading prefix segment the generation model prepended despite the
 * "no prefixes" instruction — e.g. with a `tmchow/` branch prefix the model
 * emits `tmchow/worktree-spinner`, which `sanitizeBranchSlug` folds to
 * `tmchow-worktree-spinner`. Left alone, that leaks the prefix into both the
 * branch leaf (yielding a doubled `tmchow/tmchow-...`) and the humanized
 * display name. Strips only when the leading segment matches the *configured*
 * prefix, so a work-derived name that merely starts with a real word survives.
 * Prefix-only output (the model echoed just `tmchow`) yields an empty slug so
 * the caller skips the rename — otherwise it would double-prefix to
 * `tmchow/tmchow`.
 */
export function stripConfiguredBranchPrefix(
  slug: string,
  prefix: string | null | undefined
): string {
  if (!prefix) {
    return slug
  }
  const prefixSlug = prefix
    .trim()
    .toLowerCase()
    .replace(/[^a-z0-9]+/g, '-')
    .replace(/^-+|-+$/g, '')
  if (!prefixSlug) {
    return slug
  }
  if (slug === prefixSlug) {
    return ''
  }
  return slug.startsWith(`${prefixSlug}-`) ? slug.slice(prefixSlug.length + 1) : slug
}

/**
 * Turn a branch slug into a readable workspace display label, e.g.
 * `supported-models-list` → `Supported models list`. Used to update the
 * sidebar name alongside the branch so the two stay in sync.
 */
export function humanizeBranchSlug(slug: string): string {
  const joined = slug.split('-').filter(Boolean).join(' ')
  if (!joined) {
    return ''
  }
  return joined.charAt(0).toUpperCase() + joined.slice(1)
}

export type BranchNameWorkContext = {
  /** The user's first prompt to the agent in this workspace. */
  firstPrompt: string
  /** The agent's first response, when it has already arrived. Optional because
   *  the rename fires as soon as work begins, before a reply may exist. */
  assistantMessage?: string
}

/**
 * Build the text-generation prompt that asks the configured agent to summarize
 * the work into a branch name. Kept in shared so the prompt is identical across
 * local and SSH generation targets.
 */
export function buildBranchNamePrompt(context: BranchNameWorkContext, customPrompt = ''): string {
  const sections = [
    'Generate a git branch name that summarizes the coding task described below.',
    'Rules:',
    `- Use between ${MIN_BRANCH_NAME_WORDS} and ${MAX_BRANCH_NAME_WORDS} words.`,
    '- Lowercase kebab-case only (words joined by single hyphens).',
    '- No slashes, no prefixes, no quotes, no trailing punctuation.',
    '- Describe the work itself, not the agent or the repository.',
    '- Output ONLY the branch name on a single line, nothing else.',
    '',
    'User request:',
    context.firstPrompt.trim()
  ]
  const assistant = context.assistantMessage?.trim()
  if (assistant) {
    sections.push('', "Agent's initial response:", assistant)
  }
  const prompt = customPrompt.trim()
  if (prompt) {
    sections.push('', 'Additional user prompt:', prompt)
  }
  return sections.join('\n')
}