export type ClaudeSessionKind = 'brainstorm' | 'implement' | 'test'

export const CLAUDE_SESSION_FIELDS = [
  { field: 'sessionId', kind: 'brainstorm' },
  { field: 'implementSessionId', kind: 'implement' },
  { field: 'testSessionId', kind: 'test' },
] as const satisfies ReadonlyArray<{ field: 'sessionId' | 'implementSessionId' | 'testSessionId', kind: ClaudeSessionKind }>

export interface HandoffSessions {
  sessionId?: string
  implementSessionId?: string
  testSessionId?: string
  reviewSessionId?: string
}

export interface HandoffProfiles {
  profilePath?: string
  brainstormProfilePath?: string
  testProfilePath?: string
}

export interface HandoffManifest {
  version: 1
  issue: number
  from: string
  createdAt: string
  branch?: string
  sessions: HandoffSessions
  profiles: HandoffProfiles
  claude: Array<{ id: string, kind: ClaudeSessionKind }>
  codex: Array<{ id: string, relPath: string }>
}

export const HANDOFF_MANIFEST_FILE = 'handoff.json'

export function handoffAttachmentName(issueNumber: number): string {
  return `spx-handoff-issue-${issueNumber}.tgz`
}

const KINDS: ReadonlySet<string> = new Set<ClaudeSessionKind>(['brainstorm', 'implement', 'test'])

function optString(v: unknown): string | undefined {
  return typeof v === 'string' && v.length > 0 ? v : undefined
}

export function parseHandoffManifest(json: string, expectedIssue: number): HandoffManifest {
  const raw = JSON.parse(json) as Record<string, unknown>
  if (!raw || typeof raw !== 'object')
    throw new Error('handoff.json 不是对象')
  if (raw.version !== 1)
    throw new Error(`handoff.json version 不支持：${String(raw.version)}`)
  if (raw.issue !== expectedIssue)
    throw new Error(`handoff.json 属于工单 #${String(raw.issue)}，不是 #${expectedIssue}`)
  const from = optString(raw.from)
  const createdAt = optString(raw.createdAt)
  if (!from || !createdAt)
    throw new Error('handoff.json 缺少 from / createdAt')
  const sessionsRaw = (raw.sessions ?? {}) as Record<string, unknown>
  const profilesRaw = (raw.profiles ?? {}) as Record<string, unknown>
  const claudeRaw = Array.isArray(raw.claude) ? raw.claude : []
  const codexRaw = Array.isArray(raw.codex) ? raw.codex : []
  const claude = claudeRaw.map((e) => {
    const o = e as Record<string, unknown>
    const id = optString(o.id)
    const kind = optString(o.kind)
    if (!id || !kind || !KINDS.has(kind))
      throw new Error(`handoff.json claude 条目非法：${JSON.stringify(e)}`)
    return { id, kind: kind as ClaudeSessionKind }
  })
  const codex = codexRaw.map((e) => {
    const o = e as Record<string, unknown>
    const id = optString(o.id)
    const relPath = optString(o.relPath)
    if (!id || !relPath || relPath.startsWith('/') || relPath.includes('..'))
      throw new Error(`handoff.json codex 条目非法：${JSON.stringify(e)}`)
    return { id, relPath }
  })
  const sessions: HandoffSessions = {}
  for (const k of ['sessionId', 'implementSessionId', 'testSessionId', 'reviewSessionId'] as const) {
    const v = optString(sessionsRaw[k])
    if (v)
      sessions[k] = v
  }
  const profiles: HandoffProfiles = {}
  for (const k of ['profilePath', 'brainstormProfilePath', 'testProfilePath'] as const) {
    const v = optString(profilesRaw[k])
    if (v)
      profiles[k] = v
  }
  return {
    version: 1,
    issue: expectedIssue,
    from,
    createdAt,
    ...(optString(raw.branch) ? { branch: optString(raw.branch) } : {}),
    sessions,
    profiles,
    claude,
    codex,
  }
}