// 文档职责草稿的唯一存储。三个视图只投影这份数据；单元格值由三权反推。
export type CellDuty = 'none' | 'author' | 'reviewer' | 'approver'

interface DutyRoles {
  author: string
  reviewers: string[]
  approver: string
}

export interface DutyDocDraft extends DutyRoles {
  docId: string
  title: string
  code: string
  typeKey: string
  stage: string
  dutyVersion: number
  activeRound: number
  legacySectionOverrides: number
  dirty: boolean
}

export interface DutyMember {
  owner: string
  role: string
  valid: boolean
  canAuthor: boolean
  canReview: boolean
  canApprove: boolean
}

interface DutySaveItem {
  docId: string
  author: string
  reviewers: string[]
  approver: string
  expectedDutyVersion: number
  confirmInvalidation: boolean
}

export function cellDuty(roles: DutyRoles, owner: string): CellDuty {
  if (roles.author === owner) return 'author'
  if (roles.approver === owner) return 'approver'
  if (roles.reviewers.includes(owner)) return 'reviewer'
  return 'none'
}

export function applyCell(roles: DutyRoles, owner: string, duty: CellDuty): {
  roles: DutyRoles
  replacedAuthor: string
  replacedApprover: string
} {
  const replacedAuthor = duty === 'author' && roles.author !== '' && roles.author !== owner ? roles.author : ''
  const replacedApprover = duty === 'approver' && roles.approver !== '' && roles.approver !== owner ? roles.approver : ''
  let author = roles.author === owner ? '' : roles.author
  let approver = roles.approver === owner ? '' : roles.approver
  let reviewers = roles.reviewers.filter(person => person !== owner)
  switch (duty) {
    case 'author':
      author = owner
      break
    case 'approver':
      approver = owner
      break
    case 'reviewer':
      reviewers = [...reviewers, owner]
      break
    case 'none':
      break
    default: {
      const exhaustive: never = duty
      throw new Error(exhaustive)
    }
  }
  return { roles: { author, reviewers, approver }, replacedAuthor, replacedApprover }
}

export function replacementNote(roles: DutyRoles, owner: string, duty: CellDuty): string {
  if (duty === 'author' && roles.author !== '' && roles.author !== owner) return `将替换${roles.author}`
  if (duty === 'approver' && roles.approver !== '' && roles.approver !== owner) return `将替换${roles.approver}`
  return ''
}

function dutyConflicts(roles: DutyRoles): number {
  const seen = new Map<string, number>()
  const mark = (owner: string) => {
    if (!owner) return
    seen.set(owner, (seen.get(owner) ?? 0) + 1)
  }
  mark(roles.author)
  mark(roles.approver)
  for (const reviewer of roles.reviewers) mark(reviewer)
  let conflicts = 0
  for (const count of seen.values()) if (count > 1) conflicts += 1
  return conflicts
}

export function completeness(roles: DutyRoles): { authors: number; reviewers: number; approvers: number; conflicts: number } {
  return {
    authors: roles.author ? 1 : 0,
    reviewers: roles.reviewers.length,
    approvers: roles.approver ? 1 : 0,
    conflicts: dutyConflicts(roles),
  }
}

export function saveIssues(roles: DutyRoles): string[] {
  const issues: string[] = []
  if (!roles.author) issues.push('需指定编制人')
  if (roles.reviewers.length === 0) issues.push('审核至少一人')
  if (!roles.approver) issues.push('需指定批准人')
  if (dutyConflicts(roles) > 0) issues.push('一人只能担一个职责')
  return issues
}

function rolesFromCells(docId: string, cells: { docId: string; owner: string; duty: string }[]): DutyRoles {
  const roles: DutyRoles = { author: '', reviewers: [], approver: '' }
  for (const cell of cells) {
    if (cell.docId !== docId) continue
    if (cell.duty !== 'none' && cell.duty !== 'author' && cell.duty !== 'reviewer' && cell.duty !== 'approver') continue
    const next = applyCell(roles, cell.owner, cell.duty)
    roles.author = next.roles.author
    roles.reviewers = next.roles.reviewers
    roles.approver = next.roles.approver
  }
  return roles
}

export function absorbServerDocs(
  current: DutyDocDraft[],
  docs: {
    docId: string; title: string; code?: string; typeKey: string; stage?: string
    dutyVersion: number; activeRound?: number; legacySectionOverrides?: number
  }[],
  cells: { docId: string; owner: string; duty: string }[],
  replaceDirty = false,
): DutyDocDraft[] {
  const byId = new Map(current.map(doc => [doc.docId, doc]))
  const pageIds = new Set(docs.map(doc => doc.docId))
  const next: DutyDocDraft[] = []
  for (const doc of docs) {
    const previous = byId.get(doc.docId)
    const serverRoles = rolesFromCells(doc.docId, cells)
    const keepDraft = !replaceDirty && previous?.dirty === true
    next.push({
      docId: doc.docId,
      title: doc.title,
      code: doc.code ?? doc.docId,
      typeKey: doc.typeKey,
      stage: doc.stage ?? '',
      dutyVersion: keepDraft ? previous.dutyVersion : doc.dutyVersion,
      activeRound: doc.activeRound ?? 0,
      legacySectionOverrides: doc.legacySectionOverrides ?? 0,
      dirty: keepDraft,
      author: keepDraft ? previous.author : serverRoles.author,
      reviewers: keepDraft ? previous.reviewers : serverRoles.reviewers,
      approver: keepDraft ? previous.approver : serverRoles.approver,
    })
  }
  for (const doc of current) {
    if (!replaceDirty && doc.dirty && !pageIds.has(doc.docId)) next.push(doc)
  }
  return next
}

export function editCell(docs: DutyDocDraft[], docId: string, owner: string, duty: CellDuty): DutyDocDraft[] {
  return docs.map(doc => {
    if (doc.docId !== docId) return doc
    const next = applyCell(doc, owner, duty)
    return { ...doc, ...next.roles, dirty: true }
  })
}

export function dirtyDocs(docs: DutyDocDraft[]): DutyDocDraft[] {
  return docs.filter(doc => doc.dirty)
}

export function savePayload(docs: DutyDocDraft[], confirmInvalidation: boolean): { docs: DutySaveItem[]; issues: string[] } {
  const dirty = dirtyDocs(docs)
  const issues: string[] = []
  if (dirty.length === 0) issues.push('没有未保存的职责')
  if (dirty.length > 20) issues.push('一次保存最多 20 份文档')
  for (const doc of dirty) {
    for (const issue of saveIssues(doc)) issues.push(`${doc.title}：${issue}`)
  }
  return {
    docs: dirty.slice(0, 20).map(doc => ({
      docId: doc.docId,
      author: doc.author,
      reviewers: doc.reviewers,
      approver: doc.approver,
      expectedDutyVersion: doc.dutyVersion,
      confirmInvalidation: confirmInvalidation && doc.activeRound > 0,
    })),
    issues,
  }
}