import type { BrowserSlashCommandDispatchResult, BrowserSlashCommandSurface } from "./browser-slash-command-dispatch"
import type { DoctorFixResult, DoctorReport, ForensicReport, SkillHealthReport } from "./diagnostics-types"
import type { KnowledgeData, CapturesData, CaptureResolveResult } from "./knowledge-captures-types"
import type { SettingsData } from "./settings-types"
import type {
  HistoryData,
  InspectData,
  HooksData,
  ExportResult,
  UndoInfo,
  CleanupData,
  SteerData,
} from "./remaining-command-types"
import type { GitSummaryResponse } from "./git-summary-contract"
import type {
  SessionBrowserNameFilter,
  SessionBrowserSession,
  SessionBrowserSortMode,
} from "./session-browser-contract"

export const COMMAND_SURFACE_THINKING_LEVELS = ["off", "minimal", "low", "medium", "high", "xhigh"] as const

export type CommandSurfaceThinkingLevel = (typeof COMMAND_SURFACE_THINKING_LEVELS)[number]
export type CommandSurfaceSection =
  | "general"
  | "model"
  | "thinking"
  | "queue"
  | "compaction"
  | "retry"
  | "session-behavior"
  | "recovery"
  | "auth"
  | "admin"
  | "git"
  | "resume"
  | "name"
  | "fork"
  | "session"
  | "compact"
  | "workspace"
  | "integrations"
  | "experimental"
  // GSD subcommand surfaces (S02)
  | "gsd-status"
  | "gsd-visualize"
  | "gsd-forensics"
  | "gsd-doctor"
  | "gsd-skill-health"
  | "gsd-knowledge"
  | "gsd-capture"
  | "gsd-triage"
  | "gsd-quick"
  | "gsd-history"
  | "gsd-undo"
  | "gsd-inspect"
  | "gsd-prefs"
  | "gsd-config"
  | "gsd-hooks"
  | "gsd-mode"
  | "gsd-steer"
  | "gsd-export"
  | "gsd-cleanup"
  | "gsd-queue"
export type CommandSurfaceSource = "slash" | "sidebar" | "surface"
export type CommandSurfacePendingAction =
  | "loading_models"
  | "set_model"
  | "set_thinking_level"
  | "set_steering_mode"
  | "set_follow_up_mode"
  | "set_auto_compaction"
  | "set_auto_retry"
  | "abort_retry"
  | "load_git_summary"
  | "load_recovery_diagnostics"
  | "load_session_browser"
  | "rename_session"
  | "save_api_key"
  | "start_provider_flow"
  | "submit_provider_flow_input"
  | "cancel_provider_flow"
  | "logout_provider"
  | "switch_session"
  | "load_fork_messages"
  | "fork_session"
  | "load_session_stats"
  | "export_html"
  | "compact_session"

export interface CommandSurfaceModelOption {
  provider: string
  modelId: string
  name?: string
  reasoning: boolean
  isCurrent: boolean
}

export interface CommandSurfaceForkMessage {
  entryId: string
  text: string
}

export interface CommandSurfaceSessionStats {
  sessionFile: string | undefined
  sessionId: string
  userMessages: number
  assistantMessages: number
  toolCalls: number
  toolResults: number
  totalMessages: number
  tokens: {
    input: number
    output: number
    cacheRead: number
    cacheWrite: number
    total: number
  }
  cost: number
}

export interface CommandSurfaceCompactionResult {
  summary: string
  firstKeptEntryId: string
  tokensBefore: number
  details?: unknown
}

export interface CommandSurfaceResumableSession {
  id: string
  path: string
  name?: string
  isActive: boolean
}

export interface CommandSurfaceSessionBrowserState {
  scope: "current_project" | null
  projectCwd: string | null
  projectSessionsDir: string | null
  activeSessionPath: string | null
  query: string
  sortMode: SessionBrowserSortMode
  nameFilter: SessionBrowserNameFilter
  totalSessions: number
  returnedSessions: number
  sessions: SessionBrowserSession[]
  loaded: boolean
  error: string | null
}

export interface CommandSurfaceSessionMutationState {
  pending: boolean
  sessionPath: string | null
  result: string | null
  error: string | null
}

export interface CommandSurfaceSettingMutationState {
  pending: boolean
  result: string | null
  error: string | null
}

export interface CommandSurfaceSettingsMutationState {
  steeringMode: CommandSurfaceSettingMutationState
  followUpMode: CommandSurfaceSettingMutationState
  autoCompaction: CommandSurfaceSettingMutationState
  autoRetry: CommandSurfaceSettingMutationState
  abortRetry: CommandSurfaceSettingMutationState
}

export interface CommandSurfaceGitSummaryState {
  pending: boolean
  loaded: boolean
  result: GitSummaryResponse | null
  error: string | null
}

export type WorkspaceRecoverySummaryTone = "healthy" | "warning" | "danger"
export type WorkspaceRecoveryDiagnosticsStatus = "ready" | "unavailable"
export type WorkspaceRecoveryBrowserActionId =
  | "refresh_diagnostics"
  | "refresh_workspace"
  | "open_retry_controls"
  | "open_resume_controls"
  | "open_auth_controls"
export type CommandSurfaceRecoveryPhase = "idle" | "loading" | "ready" | "unavailable" | "error"

export interface WorkspaceRecoveryBrowserAction {
  id: WorkspaceRecoveryBrowserActionId
  label: string
  detail: string
  emphasis?: "primary" | "secondary" | "danger"
}

export interface WorkspaceRecoveryCommandSuggestion {
  label: string
  command: string
}

export interface WorkspaceRecoveryCodeSummary {
  code: string
  count: number
  label: string
  severity: "info" | "warning" | "error"
}

export interface WorkspaceRecoveryIssueDigest {
  code: string
  severity: "info" | "warning" | "error"
  scope: string
  message: string
  file?: string
  suggestion?: string
  unitId?: string
}

export interface WorkspaceRecoveryDiagnostics {
  status: WorkspaceRecoveryDiagnosticsStatus
  loadedAt: string
  project: {
    cwd: string
    activeScope: string | null
    activeSessionPath: string | null
    activeSessionId: string | null
  }
  summary: {
    tone: WorkspaceRecoverySummaryTone
    label: string
    detail: string
    validationCount: number
    doctorIssueCount: number
    lastFailurePhase: string | null
    currentUnitId: string | null
    retryAttempt: number
    retryInProgress: boolean
    compactionActive: boolean
  }
  bridge: {
    phase: string
    retry: {
      enabled: boolean
      inProgress: boolean
      attempt: number
      label: string
    }
    compaction: {
      active: boolean
      label: string
    }
    lastFailure: {
      message: string
      phase: string
      at: string
      commandType: string | null
      afterSessionAttachment: boolean
    } | null
    authRefresh: {
      phase: string
      error: string | null
      label: string
    }
  }
  validation: {
    total: number
    bySeverity: {
      errors: number
      warnings: number
      infos: number
    }
    codes: WorkspaceRecoveryCodeSummary[]
    topIssues: WorkspaceRecoveryIssueDigest[]
  }
  doctor: {
    scope: string | null
    total: number
    errors: number
    warnings: number
    infos: number
    fixable: number
    codes: Array<{ code: string; count: number }>
    topIssues: WorkspaceRecoveryIssueDigest[]
  }
  interruptedRun: {
    available: boolean
    detected: boolean
    label: string
    detail: string
    unit: {
      type: string
      id: string
    } | null
    counts: {
      toolCalls: number
      filesWritten: number
      commandsRun: number
      errors: number
    }
    gitChangesDetected: boolean
    lastError: string | null
  }
  actions: {
    browser: WorkspaceRecoveryBrowserAction[]
    commands: WorkspaceRecoveryCommandSuggestion[]
  }
}

export interface CommandSurfaceRecoveryState {
  phase: CommandSurfaceRecoveryPhase
  pending: boolean
  loaded: boolean
  stale: boolean
  diagnostics: WorkspaceRecoveryDiagnostics | null
  error: string | null
  lastLoadedAt: string | null
  lastInvalidatedAt: string | null
  lastFailureAt: string | null
}

export interface WorkspaceRecoverySummary {
  visible: boolean
  tone: WorkspaceRecoverySummaryTone
  label: string
  detail: string
  validationCount: number
  retryInProgress: boolean
  retryAttempt: number
  autoRetryEnabled: boolean
  isCompacting: boolean
  currentUnitId: string | null
  freshness: "idle" | "fresh" | "stale" | "error"
  entrypointLabel: string
  lastError: {
    message: string
    phase: string
    at: string
  } | null
}

export type CommandSurfaceTarget =
  | { kind: "settings"; section: CommandSurfaceSection }
  | { kind: "model"; provider?: string; modelId?: string; query?: string }
  | { kind: "thinking"; level: CommandSurfaceThinkingLevel }
  | { kind: "auth"; providerId?: string; intent: "login" | "logout" | "manage" }
  | { kind: "resume"; sessionPath?: string }
  | { kind: "name"; sessionPath?: string; name: string }
  | { kind: "fork"; entryId?: string }
  | { kind: "session"; outputPath?: string }
  | { kind: "compact"; customInstructions: string }
  | { kind: "gsd"; surface: string; subcommand: string; args: string }

// ─── Diagnostics panel state ──────────────────────────────────────────────────

export type CommandSurfaceDiagnosticsPhase = "idle" | "loading" | "loaded" | "error"

export interface CommandSurfaceDiagnosticsPhaseState<T> {
  phase: CommandSurfaceDiagnosticsPhase
  data: T | null
  error: string | null
  lastLoadedAt: string | null
}

export interface CommandSurfaceDoctorState extends CommandSurfaceDiagnosticsPhaseState<DoctorReport> {
  fixPending: boolean
  lastFixResult: DoctorFixResult | null
  lastFixError: string | null
}

export interface CommandSurfaceDiagnosticsState {
  forensics: CommandSurfaceDiagnosticsPhaseState<ForensicReport>
  doctor: CommandSurfaceDoctorState
  skillHealth: CommandSurfaceDiagnosticsPhaseState<SkillHealthReport>
}

export function createInitialDiagnosticsPhaseState<T>(): CommandSurfaceDiagnosticsPhaseState<T> {
  return { phase: "idle", data: null, error: null, lastLoadedAt: null }
}

export function createInitialDoctorState(): CommandSurfaceDoctorState {
  return { phase: "idle", data: null, error: null, lastLoadedAt: null, fixPending: false, lastFixResult: null, lastFixError: null }
}

export function createInitialDiagnosticsState(): CommandSurfaceDiagnosticsState {
  return {
    forensics: createInitialDiagnosticsPhaseState<ForensicReport>(),
    doctor: createInitialDoctorState(),
    skillHealth: createInitialDiagnosticsPhaseState<SkillHealthReport>(),
  }
}

// ─── Knowledge/Captures panel state ──────────────────────────────────────────

export interface CommandSurfaceKnowledgeCapturesResolveState {
  pending: boolean
  lastError: string | null
  lastResult: CaptureResolveResult | null
}

export interface CommandSurfaceKnowledgeCapturesState {
  knowledge: CommandSurfaceDiagnosticsPhaseState<KnowledgeData>
  captures: CommandSurfaceDiagnosticsPhaseState<CapturesData>
  resolveRequest: CommandSurfaceKnowledgeCapturesResolveState
}

export function createInitialKnowledgeCapturesState(): CommandSurfaceKnowledgeCapturesState {
  return {
    knowledge: createInitialDiagnosticsPhaseState<KnowledgeData>(),
    captures: createInitialDiagnosticsPhaseState<CapturesData>(),
    resolveRequest: { pending: false, lastError: null, lastResult: null },
  }
}

// ─── Settings panel state ────────────────────────────────────────────────────

export type CommandSurfaceSettingsState = CommandSurfaceDiagnosticsPhaseState<SettingsData>

export function createInitialSettingsState(): CommandSurfaceSettingsState {
  return createInitialDiagnosticsPhaseState<SettingsData>()
}

// ─── Remaining command surfaces state ────────────────────────────────────────

export interface CommandSurfaceRemainingState {
  history: CommandSurfaceDiagnosticsPhaseState<HistoryData>
  inspect: CommandSurfaceDiagnosticsPhaseState<InspectData>
  hooks: CommandSurfaceDiagnosticsPhaseState<HooksData>
  exportData: CommandSurfaceDiagnosticsPhaseState<ExportResult>
  undo: CommandSurfaceDiagnosticsPhaseState<UndoInfo>
  cleanup: CommandSurfaceDiagnosticsPhaseState<CleanupData>
  steer: CommandSurfaceDiagnosticsPhaseState<SteerData>
}

export function createInitialRemainingState(): CommandSurfaceRemainingState {
  return {
    history: createInitialDiagnosticsPhaseState<HistoryData>(),
    inspect: createInitialDiagnosticsPhaseState<InspectData>(),
    hooks: createInitialDiagnosticsPhaseState<HooksData>(),
    exportData: createInitialDiagnosticsPhaseState<ExportResult>(),
    undo: createInitialDiagnosticsPhaseState<UndoInfo>(),
    cleanup: createInitialDiagnosticsPhaseState<CleanupData>(),
    steer: createInitialDiagnosticsPhaseState<SteerData>(),
  }
}

export interface WorkspaceCommandSurfaceState {
  open: boolean
  activeSurface: BrowserSlashCommandSurface | null
  source: CommandSurfaceSource | null
  section: CommandSurfaceSection | null
  args: string
  pendingAction: CommandSurfacePendingAction | null
  selectedTarget: CommandSurfaceTarget | null
  lastError: string | null
  lastResult: string | null
  availableModels: CommandSurfaceModelOption[]
  forkMessages: CommandSurfaceForkMessage[]
  sessionStats: CommandSurfaceSessionStats | null
  lastCompaction: CommandSurfaceCompactionResult | null
  gitSummary: CommandSurfaceGitSummaryState
  recovery: CommandSurfaceRecoveryState
  diagnostics: CommandSurfaceDiagnosticsState
  knowledgeCaptures: CommandSurfaceKnowledgeCapturesState
  settingsData: CommandSurfaceSettingsState
  remainingCommands: CommandSurfaceRemainingState
  sessionBrowser: CommandSurfaceSessionBrowserState
  resumeRequest: CommandSurfaceSessionMutationState
  renameRequest: CommandSurfaceSessionMutationState
  settingsRequests: CommandSurfaceSettingsMutationState
}

export interface CommandSurfaceOpenContext {
  onboardingLocked?: boolean
  currentModel?: { provider?: string; modelId?: string } | null
  currentThinkingLevel?: string | null
  preferredProviderId?: string | null
  resumableSessions?: CommandSurfaceResumableSession[]
  currentSessionPath?: string | null
  currentSessionName?: string | null
  projectCwd?: string | null
  projectSessionsDir?: string | null
}

export interface CommandSurfaceOpenRequest extends CommandSurfaceOpenContext {
  surface: BrowserSlashCommandSurface
  source: CommandSurfaceSource
  args?: string
  selectedTarget?: CommandSurfaceTarget | null
}

export interface CommandSurfaceActionResult {
  action: CommandSurfacePendingAction
  success: boolean
  message: string
  selectedTarget?: CommandSurfaceTarget | null
  availableModels?: CommandSurfaceModelOption[]
  forkMessages?: CommandSurfaceForkMessage[]
  sessionStats?: CommandSurfaceSessionStats | null
  lastCompaction?: CommandSurfaceCompactionResult | null
  gitSummary?: CommandSurfaceGitSummaryState
  recovery?: CommandSurfaceRecoveryState
  sessionBrowser?: CommandSurfaceSessionBrowserState
}

const AUTH_SURFACE_COMMANDS = new Set<BrowserSlashCommandSurface>(["settings", "login", "logout"])
const SETTINGS_MUTATION_ACTION_TO_REQUEST: Partial<
  Record<CommandSurfacePendingAction, keyof CommandSurfaceSettingsMutationState>
> = {
  set_steering_mode: "steeringMode",
  set_follow_up_mode: "followUpMode",
  set_auto_compaction: "autoCompaction",
  set_auto_retry: "autoRetry",
  abort_retry: "abortRetry",
}

function matchingSessionPath(
  sessions: CommandSurfaceResumableSession[] | undefined,
  query: string | undefined,
): string | undefined {
  if (!sessions?.length) return undefined
  const normalizedQuery = query?.trim().toLowerCase()
  if (!normalizedQuery) {
    return sessions.find((session) => !session.isActive)?.path ?? sessions[0]?.path
  }

  const exactMatch = sessions.find((session) => {
    const values = [session.id, session.name, session.path].filter(Boolean).map((value) => value!.toLowerCase())
    return values.includes(normalizedQuery)
  })
  if (exactMatch) return exactMatch.path

  return sessions.find((session) => {
    const values = [session.id, session.name, session.path].filter(Boolean).map((value) => value!.toLowerCase())
    return values.some((value) => value.includes(normalizedQuery))
  })?.path
}

function createInitialCommandSurfaceSessionBrowserState(
  overrides: Partial<CommandSurfaceSessionBrowserState> = {},
): CommandSurfaceSessionBrowserState {
  return {
    scope: null,
    projectCwd: null,
    projectSessionsDir: null,
    activeSessionPath: null,
    query: "",
    sortMode: "threaded",
    nameFilter: "all",
    totalSessions: 0,
    returnedSessions: 0,
    sessions: [],
    loaded: false,
    error: null,
    ...overrides,
  }
}

function createInitialCommandSurfaceSessionMutationState(): CommandSurfaceSessionMutationState {
  return {
    pending: false,
    sessionPath: null,
    result: null,
    error: null,
  }
}

function createInitialCommandSurfaceSettingMutationState(): CommandSurfaceSettingMutationState {
  return {
    pending: false,
    result: null,
    error: null,
  }
}

function createInitialCommandSurfaceSettingsMutationState(): CommandSurfaceSettingsMutationState {
  return {
    steeringMode: createInitialCommandSurfaceSettingMutationState(),
    followUpMode: createInitialCommandSurfaceSettingMutationState(),
    autoCompaction: createInitialCommandSurfaceSettingMutationState(),
    autoRetry: createInitialCommandSurfaceSettingMutationState(),
    abortRetry: createInitialCommandSurfaceSettingMutationState(),
  }
}

function createInitialCommandSurfaceGitSummaryState(): CommandSurfaceGitSummaryState {
  return {
    pending: false,
    loaded: false,
    result: null,
    error: null,
  }
}

export function createInitialCommandSurfaceRecoveryState(): CommandSurfaceRecoveryState {
  return {
    phase: "idle",
    pending: false,
    loaded: false,
    stale: false,
    diagnostics: null,
    error: null,
    lastLoadedAt: null,
    lastInvalidatedAt: null,
    lastFailureAt: null,
  }
}

function buildInitialSessionBrowserState(request: CommandSurfaceOpenRequest): CommandSurfaceSessionBrowserState {
  const initialQuery = request.surface === "resume" ? request.args?.trim() ?? "" : ""
  return createInitialCommandSurfaceSessionBrowserState({
    activeSessionPath: request.currentSessionPath ?? null,
    projectCwd: request.projectCwd ?? null,
    projectSessionsDir: request.projectSessionsDir ?? null,
    query: initialQuery,
    sortMode: initialQuery ? "relevance" : "threaded",
  })
}

export function isCommandSurfaceThinkingLevel(value: string | null | undefined): value is CommandSurfaceThinkingLevel {
  return COMMAND_SURFACE_THINKING_LEVELS.includes((value ?? "") as CommandSurfaceThinkingLevel)
}

export function createInitialCommandSurfaceState(): WorkspaceCommandSurfaceState {
  return {
    open: false,
    activeSurface: null,
    source: null,
    section: null,
    args: "",
    pendingAction: null,
    selectedTarget: null,
    lastError: null,
    lastResult: null,
    availableModels: [],
    forkMessages: [],
    sessionStats: null,
    lastCompaction: null,
    gitSummary: createInitialCommandSurfaceGitSummaryState(),
    recovery: createInitialCommandSurfaceRecoveryState(),
    diagnostics: createInitialDiagnosticsState(),
    knowledgeCaptures: createInitialKnowledgeCapturesState(),
    settingsData: createInitialSettingsState(),
    remainingCommands: createInitialRemainingState(),
    sessionBrowser: createInitialCommandSurfaceSessionBrowserState(),
    resumeRequest: createInitialCommandSurfaceSessionMutationState(),
    renameRequest: createInitialCommandSurfaceSessionMutationState(),
    settingsRequests: createInitialCommandSurfaceSettingsMutationState(),
  }
}

export function commandSurfaceSectionForRequest(request: CommandSurfaceOpenRequest): CommandSurfaceSection | null {
  switch (request.surface) {
    case "model":
      return "model"
    case "thinking":
      return "thinking"
    case "settings":
      return request.onboardingLocked ? "auth" : "general"
    case "git":
      return "git"
    case "login":
    case "logout":
      return "auth"
    case "resume":
      return "resume"
    case "name":
      return "name"
    case "fork":
      return "fork"
    case "session":
    case "export":
      return "session"
    case "compact":
      return "compact"
    // GSD subcommand surfaces (S02)
    case "gsd-status": return "gsd-status"
    case "gsd-visualize": return "gsd-visualize"
    case "gsd-forensics": return "gsd-forensics"
    case "gsd-doctor": return "gsd-doctor"
    case "gsd-skill-health": return "gsd-skill-health"
    case "gsd-knowledge": return "gsd-knowledge"
    case "gsd-capture": return "gsd-capture"
    case "gsd-triage": return "gsd-triage"
    case "gsd-quick": return "gsd-quick"
    case "gsd-history": return "gsd-history"
    case "gsd-undo": return "gsd-undo"
    case "gsd-inspect": return "gsd-inspect"
    case "gsd-prefs": return "gsd-prefs"
    case "gsd-config": return "gsd-config"
    case "gsd-hooks": return "gsd-hooks"
    case "gsd-mode": return "gsd-mode"
    case "gsd-steer": return "gsd-steer"
    case "gsd-export": return "gsd-export"
    case "gsd-cleanup": return "gsd-cleanup"
    case "gsd-queue": return "gsd-queue"
    default:
      return null
  }
}

function buildSettingsTarget(section: CommandSurfaceSection): CommandSurfaceTarget {
  return { kind: "settings", section }
}

function buildModelTarget(request: CommandSurfaceOpenRequest): CommandSurfaceTarget {
  const query = request.args?.trim() || undefined
  return {
    kind: "model",
    provider: request.currentModel?.provider,
    modelId: request.currentModel?.modelId,
    query,
  }
}

function buildThinkingTarget(request: CommandSurfaceOpenRequest): CommandSurfaceTarget {
  const requestedLevel = request.args?.trim().toLowerCase() || ""
  const level = isCommandSurfaceThinkingLevel(requestedLevel)
    ? requestedLevel
    : isCommandSurfaceThinkingLevel(request.currentThinkingLevel)
      ? request.currentThinkingLevel
      : "off"

  return {
    kind: "thinking",
    level,
  }
}

function buildAuthTarget(request: CommandSurfaceOpenRequest): CommandSurfaceTarget {
  const requestedProviderId = request.args?.trim() || undefined
  return {
    kind: "auth",
    providerId: requestedProviderId ?? request.preferredProviderId ?? undefined,
    intent: request.surface === "login" ? "login" : request.surface === "logout" ? "logout" : "manage",
  }
}

function buildResumeTarget(request: CommandSurfaceOpenRequest): Extract<CommandSurfaceTarget, { kind: "resume" }> {
  const selectedPath = matchingSessionPath(request.resumableSessions, request.args)
  return {
    kind: "resume",
    sessionPath: selectedPath,
  }
}

function buildNameTarget(request: CommandSurfaceOpenRequest): CommandSurfaceTarget {
  const providedName = request.args?.trim()
  return {
    kind: "name",
    sessionPath: request.currentSessionPath ?? undefined,
    name: providedName !== undefined && providedName.length > 0 ? providedName : request.currentSessionName?.trim() ?? "",
  }
}

function buildForkTarget(request: CommandSurfaceOpenRequest): CommandSurfaceTarget {
  const entryId = request.args?.trim() || undefined
  return {
    kind: "fork",
    entryId,
  }
}

function buildSessionTarget(request: CommandSurfaceOpenRequest): CommandSurfaceTarget {
  const outputPath = request.args?.trim() || undefined
  return {
    kind: "session",
    outputPath,
  }
}

function buildCompactTarget(request: CommandSurfaceOpenRequest): CommandSurfaceTarget {
  return {
    kind: "compact",
    customInstructions: request.args?.trim() ?? "",
  }
}

export function buildCommandSurfaceTarget(request: CommandSurfaceOpenRequest): CommandSurfaceTarget | null {
  if (request.selectedTarget !== undefined) {
    return request.selectedTarget
  }

  const section = commandSurfaceSectionForRequest(request)
  if (!section) return null

  if (request.surface === "settings") {
    return buildSettingsTarget(section)
  }

  if (request.surface === "model") {
    return buildModelTarget(request)
  }

  if (request.surface === "thinking") {
    return buildThinkingTarget(request)
  }

  if (AUTH_SURFACE_COMMANDS.has(request.surface)) {
    return buildAuthTarget(request)
  }

  if (request.surface === "resume") {
    return buildResumeTarget(request)
  }

  if (request.surface === "name") {
    return buildNameTarget(request)
  }

  if (request.surface === "fork") {
    return buildForkTarget(request)
  }

  if (request.surface === "session" || request.surface === "export") {
    return buildSessionTarget(request)
  }

  if (request.surface === "compact") {
    return buildCompactTarget(request)
  }

  // GSD subcommand surfaces — generic target (S02)
  if (request.surface?.startsWith("gsd-")) {
    const subcommand = request.surface.slice(4) // "gsd-forensics" -> "forensics"
    return { kind: "gsd", surface: request.surface, subcommand, args: request.args ?? "" }
  }

  return buildSettingsTarget(section)
}

export function openCommandSurfaceState(
  current: WorkspaceCommandSurfaceState,
  request: CommandSurfaceOpenRequest,
): WorkspaceCommandSurfaceState {
  const section = commandSurfaceSectionForRequest(request)
  return {
    ...current,
    open: true,
    activeSurface: request.surface,
    source: request.source,
    section,
    args: request.args?.trim() ?? "",
    pendingAction: null,
    selectedTarget: buildCommandSurfaceTarget(request),
    lastError: null,
    lastResult: null,
    sessionStats: null,
    forkMessages: [],
    lastCompaction: null,
    gitSummary: createInitialCommandSurfaceGitSummaryState(),
    recovery: createInitialCommandSurfaceRecoveryState(),
    diagnostics: createInitialDiagnosticsState(),
    knowledgeCaptures: createInitialKnowledgeCapturesState(),
    settingsData: createInitialSettingsState(),
    remainingCommands: createInitialRemainingState(),
    sessionBrowser: buildInitialSessionBrowserState(request),
    resumeRequest: createInitialCommandSurfaceSessionMutationState(),
    renameRequest: createInitialCommandSurfaceSessionMutationState(),
    settingsRequests: createInitialCommandSurfaceSettingsMutationState(),
  }
}

export function closeCommandSurfaceState(current: WorkspaceCommandSurfaceState): WorkspaceCommandSurfaceState {
  return {
    ...current,
    open: false,
    pendingAction: null,
  }
}

export function setCommandSurfaceSection(
  current: WorkspaceCommandSurfaceState,
  section: CommandSurfaceSection,
  context: CommandSurfaceOpenContext = {},
): WorkspaceCommandSurfaceState {
  const request: CommandSurfaceOpenRequest = {
    surface: current.activeSurface ?? "settings",
    source: current.source ?? "surface",
    args: current.args,
    ...context,
  }

  const currentSessionPath =
    current.selectedTarget?.kind === "resume"
      ? current.selectedTarget.sessionPath
      : current.selectedTarget?.kind === "name"
        ? current.selectedTarget.sessionPath
        : undefined
  const currentDraftName = current.selectedTarget?.kind === "name" ? current.selectedTarget.name : undefined

  let selectedTarget: CommandSurfaceTarget | null = current.selectedTarget
  if (section === "model") {
    selectedTarget = buildModelTarget(request)
  } else if (section === "thinking") {
    selectedTarget = buildThinkingTarget(request)
  } else if (section === "general" || section === "session-behavior" || section === "queue" || section === "compaction" || section === "retry" || section === "recovery" || section === "git" || section === "admin") {
    selectedTarget = buildSettingsTarget(section)
  } else if (section === "auth") {
    selectedTarget = buildAuthTarget({
      ...request,
      surface:
        current.activeSurface === "logout"
          ? "logout"
          : current.activeSurface === "login"
            ? "login"
            : "settings",
    })
  } else if (section === "resume") {
    selectedTarget = { kind: "resume", sessionPath: currentSessionPath ?? buildResumeTarget(request).sessionPath }
  } else if (section === "name") {
    selectedTarget = {
      kind: "name",
      sessionPath: currentSessionPath ?? request.currentSessionPath ?? undefined,
      name: currentDraftName ?? request.currentSessionName?.trim() ?? "",
    }
  } else if (section === "fork") {
    selectedTarget = buildForkTarget(request)
  } else if (section === "session") {
    selectedTarget = buildSessionTarget(request)
  } else if (section === "compact") {
    selectedTarget = buildCompactTarget(request)
  }

  return {
    ...current,
    section,
    selectedTarget,
  }
}

export function selectCommandSurfaceStateTarget(
  current: WorkspaceCommandSurfaceState,
  target: CommandSurfaceTarget,
): WorkspaceCommandSurfaceState {
  const nextSection =
    target.kind === "settings"
      ? target.section
      : target.kind === "model"
        ? "model"
        : target.kind === "thinking"
          ? "thinking"
          : target.kind === "auth"
            ? "auth"
            : target.kind === "resume"
              ? "resume"
              : target.kind === "name"
                ? "name"
                : target.kind === "fork"
                  ? "fork"
                  : target.kind === "session"
                    ? "session"
                    : "compact"

  return {
    ...current,
    section: nextSection,
    selectedTarget: target,
    lastError: null,
    lastResult: null,
  }
}

export function setCommandSurfacePending(
  current: WorkspaceCommandSurfaceState,
  action: CommandSurfacePendingAction,
  selectedTarget: CommandSurfaceTarget | null = current.selectedTarget,
): WorkspaceCommandSurfaceState {
  const nextResumeRequest =
    action === "switch_session"
      ? {
          pending: true,
          sessionPath: selectedTarget?.kind === "resume" ? selectedTarget.sessionPath ?? null : null,
          result: null,
          error: null,
        }
      : current.resumeRequest

  const nextRenameRequest =
    action === "rename_session"
      ? {
          pending: true,
          sessionPath: selectedTarget?.kind === "name" ? selectedTarget.sessionPath ?? null : null,
          result: null,
          error: null,
        }
      : current.renameRequest

  const settingsRequestKey = SETTINGS_MUTATION_ACTION_TO_REQUEST[action]
  const nextSettingsRequests = settingsRequestKey
    ? {
        ...current.settingsRequests,
        [settingsRequestKey]: {
          pending: true,
          result: null,
          error: null,
        },
      }
    : current.settingsRequests

  return {
    ...current,
    pendingAction: action,
    selectedTarget,
    lastError: null,
    lastResult: null,
    gitSummary:
      action === "load_git_summary"
        ? {
            ...current.gitSummary,
            pending: true,
            error: null,
          }
        : current.gitSummary,
    recovery:
      action === "load_recovery_diagnostics"
        ? {
            ...current.recovery,
            pending: true,
            error: null,
            phase: current.recovery.loaded ? current.recovery.phase : "loading",
          }
        : current.recovery,
    sessionBrowser:
      action === "load_session_browser"
        ? {
            ...current.sessionBrowser,
            error: null,
          }
        : current.sessionBrowser,
    resumeRequest: nextResumeRequest,
    renameRequest: nextRenameRequest,
    settingsRequests: nextSettingsRequests,
  }
}

export function applyCommandSurfaceActionResult(
  current: WorkspaceCommandSurfaceState,
  result: CommandSurfaceActionResult,
): WorkspaceCommandSurfaceState {
  const nextSelectedTarget = result.selectedTarget === undefined ? current.selectedTarget : result.selectedTarget
  const resumeSessionPath =
    (nextSelectedTarget?.kind === "resume" ? nextSelectedTarget.sessionPath : undefined) ?? current.resumeRequest.sessionPath
  const renameSessionPath =
    (nextSelectedTarget?.kind === "name" ? nextSelectedTarget.sessionPath : undefined) ?? current.renameRequest.sessionPath
  const settingsRequestKey = SETTINGS_MUTATION_ACTION_TO_REQUEST[result.action]
  const nextSettingsRequests = settingsRequestKey
    ? {
        ...current.settingsRequests,
        [settingsRequestKey]: {
          pending: false,
          result: result.success ? result.message : null,
          error: result.success ? null : result.message,
        },
      }
    : current.settingsRequests

  return {
    ...current,
    pendingAction: null,
    selectedTarget: nextSelectedTarget,
    availableModels: result.availableModels ?? current.availableModels,
    forkMessages: result.forkMessages ?? current.forkMessages,
    sessionStats: result.sessionStats === undefined ? current.sessionStats : result.sessionStats,
    lastCompaction: result.lastCompaction === undefined ? current.lastCompaction : result.lastCompaction,
    gitSummary:
      result.gitSummary === undefined
        ? current.gitSummary
        : {
            ...result.gitSummary,
            pending: false,
            loaded: result.gitSummary.loaded || result.success,
          },
    recovery: result.recovery ?? current.recovery,
    sessionBrowser: result.sessionBrowser ?? current.sessionBrowser,
    resumeRequest:
      result.action === "switch_session"
        ? {
            pending: false,
            sessionPath: resumeSessionPath ?? null,
            result: result.success ? result.message : null,
            error: result.success ? null : result.message,
          }
        : current.resumeRequest,
    renameRequest:
      result.action === "rename_session"
        ? {
            pending: false,
            sessionPath: renameSessionPath ?? null,
            result: result.success ? result.message : null,
            error: result.success ? null : result.message,
          }
        : current.renameRequest,
    settingsRequests: nextSettingsRequests,
    lastError: result.success ? null : result.message,
    lastResult: result.success ? result.message : null,
  }
}

export function surfaceOutcomeToOpenRequest(
  outcome: Extract<BrowserSlashCommandDispatchResult, { kind: "surface" }>,
  context: CommandSurfaceOpenContext = {},
): CommandSurfaceOpenRequest {
  return {
    surface: outcome.surface,
    source: "slash",
    args: outcome.args,
    ...context,
  }
}