import { NextRequest, NextResponse } from 'next/server'
import { getServerSession } from 'next-auth'
import { authOptions } from '@/lib/auth'
import { prisma } from '@/lib/prisma'
import { getAllMaterialTypes, isSuperAdmin } from '@/lib/department-permission'
import { filterSelectableMaterialTypes } from '@/lib/material-type-options'
import {
  collectOccupiedOrganizationPaths,
  pruneOrganizationTree,
  resolveOrganizationPermissionKey,
  type MaterialPermissionFlags,
} from '@/lib/organization-material-permissions'

type OrgNode = {
  id: string
  name: string
  path: string
  level: number
  parentId: string | null
  children: OrgNode[]
}

const emptyFlags = (): MaterialPermissionFlags => ({
  canView: false,
  canDownload: false,
  canDownloadSource: false,
  canShare: true,
  canEditAssets: false,
})

async function requireSuperAdmin() {
  const session = await getServerSession(authOptions)
  const userId = (session?.user as { id?: string } | undefined)?.id
  if (!session || !(await isSuperAdmin(userId))) {
    return null
  }
  return session
}

export async function GET() {
  try {
    if (!(await requireSuperAdmin())) {
      return NextResponse.json({ error: '需要超级管理员权限' }, { status: 403 })
    }

    const [units, rows, materialTypes, bindings] = await Promise.all([
      prisma.organizationUnit.findMany({
        where: { isActive: true },
        select: { id: true, name: true, path: true, level: true, parentId: true },
        orderBy: [{ level: 'asc' }, { name: 'asc' }],
      }),
      prisma.departmentMaterialPermission.findMany({
        select: {
          department: true,
          materialType: true,
          canView: true,
          canDownload: true,
          canDownloadSource: true,
          canShare: true,
        },
      }),
      getAllMaterialTypes().then(filterSelectableMaterialTypes),
      prisma.userEmployeeBinding.findMany({
        where: { status: 'ACTIVE', user: { isActive: true } },
        select: { employeeProfile: { select: { departmentPath: true } } },
      }),
    ])

    const stored = new Map<string, Record<string, MaterialPermissionFlags>>()
    for (const row of rows) {
      const current = stored.get(row.department) || {}
      current[row.materialType] = {
        canView: row.canView,
        canDownload: row.canDownload,
        canDownloadSource: row.canDownloadSource,
        canShare: row.canShare,
        canEditAssets: false,
      }
      stored.set(row.department, current)
    }
    const storedKeys = new Set(stored.keys())

    const nodeMap = new Map<string, OrgNode>()
    for (const unit of units) {
      nodeMap.set(unit.id, { ...unit, children: [] })
    }
    const roots: OrgNode[] = []
    for (const node of Array.from(nodeMap.values())) {
      if (node.parentId && nodeMap.has(node.parentId)) {
        nodeMap.get(node.parentId)!.children.push(node)
      } else {
        roots.push(node)
      }
    }
    const occupiedPaths = collectOccupiedOrganizationPaths(
      bindings.map((binding) => binding.employeeProfile?.departmentPath),
    )
    const tree = pruneOrganizationTree(roots, occupiedPaths)

    const permissions: Record<string, Record<string, MaterialPermissionFlags>> = {}
    const sources: Record<string, { source: string; storageKey: string | null; inheritFrom: string | null }> = {}

    for (const unit of units) {
      const resolved = resolveOrganizationPermissionKey(unit.path, storedKeys)
      const flags: Record<string, MaterialPermissionFlags> = {}
      const storedFlags = resolved && resolved.source !== 'none' ? stored.get(resolved.key) || {} : {}
      for (const materialType of materialTypes) {
        flags[materialType] = storedFlags[materialType] ? { ...storedFlags[materialType] } : emptyFlags()
      }
      permissions[unit.path] = flags
      sources[unit.path] = {
        source: resolved?.source || 'none',
        storageKey: resolved && resolved.source !== 'none' ? resolved.key : null,
        inheritFrom: resolved?.inheritFrom || null,
      }
    }

    return NextResponse.json({
      tree,
      materialTypes,
      permissions,
      sources,
    })
  } catch (error) {
    console.error('[organization material-permissions] GET failed', error)
    return NextResponse.json({ error: '获取部门权限配置失败' }, { status: 500 })
  }
}

export async function PUT(request: NextRequest) {
  try {
    if (!(await requireSuperAdmin())) {
      return NextResponse.json({ error: '需要超级管理员权限' }, { status: 403 })
    }

    const body = await request.json()
    const path = String(body?.path || '').trim()
    const action = String(body?.action || 'save')
    const incoming: Array<{
      materialType: string
      canView?: boolean
      canDownload?: boolean
      canDownloadSource?: boolean
      canShare?: boolean
    }> = Array.isArray(body?.permissions) ? body.permissions : []

    const unit = await prisma.organizationUnit.findFirst({
      where: { isActive: true, path },
      select: { path: true, name: true },
    })
    if (!unit) {
      return NextResponse.json({ error: '花名册里没有这个部门' }, { status: 400 })
    }

    if (action === 'inherit') {
      await prisma.departmentMaterialPermission.deleteMany({
        where: { department: unit.path },
      })
      return NextResponse.json({ ok: true })
    }

    if (incoming.length === 0) {
      return NextResponse.json({ error: '素材类型列表不能为空' }, { status: 400 })
    }

    await prisma.$transaction(
      incoming
        .filter((item) => item.materialType)
        .map((item) =>
          prisma.departmentMaterialPermission.upsert({
            where: {
              department_materialType: {
                department: unit.path,
                materialType: item.materialType,
              },
            },
            update: {
              canView: item.canView ?? false,
              canDownload: item.canDownload ?? false,
              canDownloadSource: item.canDownloadSource ?? false,
              canShare: item.canShare ?? true,
              linkedToDepartment: null,
            },
            create: {
              department: unit.path,
              materialType: item.materialType,
              canView: item.canView ?? false,
              canDownload: item.canDownload ?? false,
              canDownloadSource: item.canDownloadSource ?? false,
              canShare: item.canShare ?? true,
              linkedToDepartment: null,
            },
          }),
        ),
    )

    return NextResponse.json({ ok: true })
  } catch (error) {
    console.error('[organization material-permissions] PUT failed', error)
    return NextResponse.json({ error: '保存部门权限配置失败' }, { status: 500 })
  }
}