// 文档驾驶舱 I2 纯逻辑层（rollout I2；契约：Dev 仓 docs/superpowers/specs
// 2026-10-16-document-visualization-read-model-contract.md @ 37b272ba，
// 四项取舍冻结见 plans/…-rollout.md §7）。只放可测判定：筛选切换、统计呈现
//（真 0 vs 不可算）、快照一致性与更新提示、上下文键与选择保留。组件只做取数编排与渲染。

// ---- 契约类型（I1 后端 DTO 的前端精简形态） ----

export interface CockpitNodeRef { kind: string; id: string; version?: string }

export interface CockpitMeta {
  schemaVersion: string
  projectId: string
  snapshotRevision: string
  asOfSeq: number
  generatedAt: string
  truncated: boolean
  truncationReasons?: string[]
}

export interface CockpitNodeState {
  content: string // complete|partial|empty|inaccessible|unavailable
  verification: string // verified|mixed|unverified|disputed|not_applicable
  sourceCount: number
  conflictCount: number
  impactCount: number
  missingChildCount: number
  structuralGap: boolean
}

export interface CockpitTreeNode {
  ref: CockpitNodeRef
  title: string
  path: string[]
  parent?: CockpitNodeRef
  childCount: number
  state: CockpitNodeState
  lastChangedAt?: string
  lastChangedBy?: string
  visibility: string // full|redacted|metadata_only
}

export interface CockpitStats {
  documentCount: number
  completion: { known: number; total: number; state: string }
  emptyNodeCount: number
  unverifiedSourceCount: number
  conflictCount: number
  pendingChangeCount: number | null
  updatedAt?: string
  statReasons: Record<string, string>
}

export interface CockpitChangeSummary {
  node: CockpitNodeRef
  title: string
  changedAt: string
  actor?: string
  kind: string
  summary: string
  version?: string
}

export interface CockpitOverview {
  meta: CockpitMeta
  project: { title: string }
  stats: CockpitStats
  documents: CockpitTreeNode[]
  recentChanges: CockpitChangeSummary[]
}

export interface CockpitTreePage {
  meta: CockpitMeta
  items: CockpitTreeNode[]
  nextCursor?: string
  hasMore: boolean
}

// ---- 统计带：点击即切换共享筛选（视图规格 §2；未知筛选由后端 400 拒绝） ----

export const STAT_FILTERS: { key: string; label: string; filter: string }[] = [
  { key: 'empty', label: '空缺节点', filter: 'state:empty' },
  { key: 'unverified', label: '未核实来源', filter: 'state:unverified' },
  { key: 'conflict', label: '冲突', filter: 'state:conflict' },
]

/** 点击统计卡：同筛选再次点击＝清除（只定位，不执行写入）。 */
export function toggleFilter(current: string, filter: string): string {
  return current === filter ? '' : filter
}

/** 统计呈现：null（不可算）显示 — 加原因；真 0 显示 0。两侧都不得互相冒充（契约 §2/§6）。 */
export function statDisplay(stats: CockpitStats, key: string): { value: string; hint?: string } {
  const reasons = stats.statReasons || {}
  if (key === 'documents') return { value: String(stats.documentCount) }
  if (key === 'completion') {
    const c = stats.completion
    if (c.state === 'unavailable') return { value: '—', hint: reasons['completion'] || '无法计算' }
    if (c.state === 'partial') return { value: `${c.known}/${c.total}`, hint: '部分计算' }
    return { value: `${c.known}/${c.total}` }
  }
  const map: Record<string, number | null | undefined> = {
    empty: stats.emptyNodeCount,
    unverified: stats.unverifiedSourceCount,
    conflict: stats.conflictCount,
    pending: stats.pendingChangeCount,
  }
  const v = map[key]
  // 原因表按后端 DTO 字段名（statReasons 键=字段名），展示键需映射。
  const reasonKey: Record<string, string> = {
    empty: 'emptyNodeCount', unverified: 'unverifiedSourceCount',
    conflict: 'conflictCount', pending: 'pendingChangeCount',
  }
  if (v === null || v === undefined) return { value: '—', hint: reasons[reasonKey[key] || key] || '暂不可计算' }
  return { value: String(v) }
}

// ---- 快照一致性（DV-R05 前端侧）：统计与树徽标同快照才同屏可信 ----

export function sameSnapshot(a?: CockpitMeta, b?: CockpitMeta): boolean {
  if (!a || !b) return false
  return a.snapshotRevision === b.snapshotRevision && a.asOfSeq === b.asOfSeq
}

/** 更新提示：展示中快照落后于最新已见快照时提示刷新（不抢占滚动，视图规格 §5）。 */
export function updateNotice(viewed: CockpitMeta | null, latest: CockpitMeta | null): string | null {
  if (!viewed || !latest) return null
  if (viewed.snapshotRevision === latest.snapshotRevision && viewed.asOfSeq === latest.asOfSeq) return null
  return `内容已更新（快照 ${latest.snapshotRevision}）——刷新查看最新状态`
}

/** 上下文键：项目+筛选标识一轮取数上下文；不匹配的旧响应直接丢弃（契约 §8）。 */
export function contextKey(projectId: string, filter: string): string {
  return `${projectId}\u0001${filter}`
}

/** 刷新不重置选择：文档仍在根清单（或选中章节的父文档仍在）则保留，否则清空。 */
export function selectionSurvives(
  selected: CockpitNodeRef | null,
  rootDocIds: string[],
  parentDocId?: string,
): CockpitNodeRef | null {
  if (!selected) return null
  if (selected.kind === 'document') return rootDocIds.includes(selected.id) ? selected : null
  if (parentDocId && rootDocIds.includes(parentDocId)) return selected
  return null
}

/** 树行徽标（诚实状态：空/部分/受限/未核实/冲突计数；不虚构成功）。 */
export function treeBadges(n: CockpitTreeNode): string[] {
  const out: string[] = []
  if (n.state.content === 'empty') out.push('空')
  else if (n.state.content === 'partial') out.push('部分')
  else if (n.state.content === 'inaccessible') out.push('受限')
  if (n.visibility === 'metadata_only') out.push('仅元数据')
  if (n.state.verification === 'unverified') out.push('未核实')
  if (n.state.conflictCount > 0) out.push(`冲突 ${n.state.conflictCount}`)
  return out
}

/** 节点状态一句话总结（全景 §4.2）。 */
export function nodeSummaryLine(n: CockpitTreeNode): string {
  const parts: string[] = []
  const content = { complete: '内容完整', partial: '内容部分', empty: '内容为空', inaccessible: '内容受限', unavailable: '暂不可读' }[n.state.content] || n.state.content
  parts.push(content)
  if (n.state.structuralGap) parts.push('层级止于章节')
  if (n.state.sourceCount > 0) parts.push(`来源 ${n.state.sourceCount}`)
  if (n.state.conflictCount > 0) parts.push(`冲突 ${n.state.conflictCount}`)
  if (n.state.impactCount > 0) parts.push(`影响 ${n.state.impactCount}`)
  return parts.join(' · ')
}

// ---- I3：阅读器与右栏纯逻辑 ----

export interface CockpitVersionSummary {
  seq: number
  version: string
  actor?: string
  at: string
  basisCount: number
  content?: string
  redacted?: boolean
}

export interface CockpitContentBlock { kind: string; text?: string; reason?: string }

export interface CockpitSourceSummary {
  ref: { kind: string; id: string }
  label: string
  capturedAt?: string
  confidence: string
  verification: string
  visibility: string
  redactedReason?: string
}

export interface CockpitHistorySummary {
  seq: number
  at: string
  op: string
  actor?: string
  summary: string
  operationId?: string
}

export interface CockpitImpactSummary {
  ref: { kind: string; id: string }
  edgeType: string
  edgeState: string
  direction: string
  layer: string
}

export interface CockpitAssertion { node: CockpitNodeRef; claim: string; visibility: string; redactedReason?: string }

export interface CockpitConflictSummary {
  id: string
  node: CockpitNodeRef
  state: string
  left: CockpitAssertion
  right: CockpitAssertion
  detectedAt: string
  resolutionRef?: string
}

export interface CockpitPage<T> { meta?: CockpitMeta; items: T[]; nextCursor?: string; hasMore: boolean; truncated?: boolean }

export const PANEL_TABS = [
  { id: 'sources', label: '内容来源' },
  { id: 'history', label: '修改历史' },
  { id: 'impacts', label: '影响对象' },
  { id: 'conflicts', label: '冲突与风险' },
] as const
export type PanelTabId = (typeof PANEL_TABS)[number]['id']

export type ViewMode = 'panorama' | 'reader'
export type Density = 'compact' | 'full'

export interface CockpitPrefs {
  lastView: ViewMode
  density: Density
  rightPanelTab: PanelTabId
}

/** 偏好按 用户+项目 隔离（设计 §7.3）；仅本地存储，不构成授权。 */
export function prefsKey(actor: string, projectId: string): string {
  return `cockpit-prefs:${actor}:${projectId}`
}

/** 解析偏好：枚举外的脏值逐项回落默认（panorama+compact+sources）。 */
export function mergePrefs(raw: unknown): CockpitPrefs {
  const base: CockpitPrefs = { lastView: 'panorama', density: 'compact', rightPanelTab: 'sources' }
  if (!raw || typeof raw !== 'object') return base
  const r = raw as Record<string, unknown>
  const out = { ...base }
  if (r.lastView === 'panorama' || r.lastView === 'reader') out.lastView = r.lastView
  if (r.density === 'compact' || r.density === 'full') out.density = r.density
  if (PANEL_TABS.some(t => t.id === r.rightPanelTab)) out.rightPanelTab = r.rightPanelTab as PanelTabId
  return out
}

export function loadPrefs(actor: string, projectId: string): CockpitPrefs {
  try {
    const raw = typeof localStorage !== 'undefined' ? localStorage.getItem(prefsKey(actor, projectId)) : null
    return mergePrefs(raw ? JSON.parse(raw) : null)
  } catch {
    return mergePrefs(null)
  }
}

export function savePrefs(actor: string, projectId: string, prefs: CockpitPrefs): void {
  try {
    if (typeof localStorage !== 'undefined') localStorage.setItem(prefsKey(actor, projectId), JSON.stringify(prefs))
  } catch { /* 存储不可用时偏好静默降级为会话内 */ }
}

/** 版本摘要：当前版本 + 前一版本（视图规格 §5）。versions 为最新在前；受限版本无 content。 */
export function versionSummary(versions: CockpitVersionSummary[] | undefined): {
  current?: CockpitVersionSummary
  previous?: CockpitVersionSummary
  redacted: boolean
} {
  if (!versions || versions.length === 0) return { redacted: false }
  const current = versions[0]
  const previous = versions.length > 1 ? versions[1] : undefined
  return { current, previous, redacted: !!current.redacted }
}

/** 历史面板合并：只接受严格更新（seq 更大且未见）的条目；过期与重复都计入 dropped（DV-R05/契约 §8）。 */
export function mergeHistoryStrict(existing: CockpitHistorySummary[], incoming: CockpitHistorySummary[]): {
  items: CockpitHistorySummary[]
  dropped: number
} {
  const seen = new Set(existing.map(e => e.seq))
  const maxSeq = existing.length > 0 ? Math.max(...seen) : -1
  const items = [...existing]
  let dropped = 0
  for (const e of incoming) {
    if (e.seq <= maxSeq || seen.has(e.seq)) {
      dropped++
      continue
    }
    seen.add(e.seq)
    items.push(e)
  }
  return { items, dropped }
}

/** 阅读器装配：把文档的章节详情按树顺序组装为连续正文；受限章节给占位说明而非空白。 */
export function assembleReader(
  sections: CockpitTreeNode[],
  details: Record<string, { body?: CockpitContentBlock[]; versions?: CockpitVersionSummary[] } | undefined>,
): { ref: CockpitNodeRef; title: string; contentState: string; blocks: CockpitContentBlock[]; versions?: CockpitVersionSummary[] }[] {
  return sections.map(sec => {
    const d = details[sec.ref.id]
    const readable = !!d?.body && d.body.length > 0 && d.body[0].kind === 'text'
    const restricted = !!d?.body && d.body.length > 0 && d.body[0].kind === 'restricted'
    const blocks: CockpitContentBlock[] = readable
      ? (d!.body as CockpitContentBlock[])
      : restricted
        ? [{ kind: 'restricted', reason: d?.body?.[0]?.reason || 'section-duty-or-authorship' }]
        : [{ kind: 'restricted', reason: 'not_loaded' }]
    return { ref: sec.ref, title: sec.title, contentState: sec.state.content, blocks, versions: d?.versions }
  })
}

/** 行级差异（阅读器 Collapsible 的完整对比）：按行对齐的朴素 LCS 免实现——
 * 以行为单位做集合比对标记 +/=/-，足够呈现「完整差异」而不冒充精确补丁。 */
export function diffLines(current: string, previous: string): { flag: '+' | '-' | '='; text: string }[] {
  const cur = current.split('\n')
  const prev = new Set(previous.split('\n'))
  const curSet = new Set(cur)
  const out: { flag: '+' | '-' | '='; text: string }[] = []
  for (const line of cur) out.push({ flag: prev.has(line) ? '=' : '+', text: line })
  for (const line of previous.split('\n')) if (!curSet.has(line)) out.push({ flag: '-', text: line })
  return out
}

/** 历史条目的自然语言时间线文本（右栏 §6）。 */
export function historyLine(h: CockpitHistorySummary): string {
  const who = h.actor ? `${h.actor} ` : ''
  return `${h.summary}（${who}${new Date(h.at).toLocaleString('zh-CN')}）`
}