import * as React from 'react'

import { AppDataTable, type AppDataTableColumn } from '@/components/app/AppDataTable'
import { AppEmptyState } from '@/components/app/AppEmptyState'
import { AppPageHeader } from '@/components/app/AppPageHeader'
import { Badge } from '@/components/ui/badge'
import { Button } from '@/components/ui/button'
import { Checkbox } from '@/components/ui/checkbox'
import { Dialog, DialogContent, DialogDescription, DialogFooter, DialogHeader, DialogTitle } from '@/components/ui/dialog'
import { Input } from '@/components/ui/input'

import { createRole, listPermissions, listRoles, setRolePermissions } from './api'
import type { Permission, RoleDetail } from './types'

export function SystemRolesPage() {
  const [roles, setRoles] = React.useState<RoleDetail[]>([])
  const [permissions, setPermissions] = React.useState<Permission[]>([])
  const [roleName, setRoleName] = React.useState('')
  const [editingRole, setEditingRole] = React.useState<RoleDetail | null>(null)
  const [error, setError] = React.useState('')

  const load = React.useCallback(async () => {
    try {
      const [nextRoles, nextPermissions] = await Promise.all([listRoles(), listPermissions()])
      setRoles(nextRoles)
      setPermissions(nextPermissions)
      setError('')
    } catch (reason) {
      setError(reason instanceof Error ? reason.message : '加载失败')
    }
  }, [])

  React.useEffect(() => {
    void load()
  }, [load])

  async function handleCreate(event: React.FormEvent<HTMLFormElement>) {
    event.preventDefault()
    await createRole({ name: roleName, permission_codes: [] })
    setRoleName('')
    await load()
  }

  const columns: AppDataTableColumn<RoleDetail>[] = [
    {
      key: 'name',
      header: '角色',
      cell: (role) => <span className="font-medium text-foreground">{role.name}</span>
    },
    {
      key: 'permissions',
      header: '权限数量',
      cell: (role) => <Badge variant="info">{role.permission_codes.length}</Badge>
    },
    {
      key: 'summary',
      header: '权限摘要',
      cell: (role) => (
        <div className="flex max-w-[520px] flex-wrap gap-1">
          {role.permission_codes.slice(0, 6).map((code) => <Badge key={code} variant="secondary">{code}</Badge>)}
          {role.permission_codes.length > 6 ? <Badge variant="outline">+{role.permission_codes.length - 6}</Badge> : null}
        </div>
      )
    },
    {
      key: 'actions',
      header: '操作',
      cell: (role) => <Button variant="ghost" onClick={() => setEditingRole(role)}>配置权限</Button>
    }
  ]

  return (
    <main className="min-h-screen bg-background p-6 text-foreground">
      <div className="mx-auto flex max-w-7xl flex-col gap-4">
        <AppPageHeader title="角色权限" description="定义后台角色，并将系统权限授予对应角色。" />

        <form className="grid gap-3 rounded-lg border border-border bg-surface p-3 md:grid-cols-[minmax(0,360px)_auto]" onSubmit={handleCreate}>
          <Input placeholder="角色名称" value={roleName} onChange={(event) => setRoleName(event.target.value)} required />
          <Button type="submit">创建角色</Button>
        </form>

        {error ? <AppEmptyState title="无法加载角色" description={error} /> : null}
        {!error ? (
          <AppDataTable
            columns={columns}
            rows={roles}
            getRowKey={(role) => role.id}
            emptyTitle="暂无角色"
            emptyDescription="创建角色后可继续配置权限。"
          />
        ) : null}

        <RolePermissionDialog
          role={editingRole}
          permissions={permissions}
          onClose={() => setEditingRole(null)}
          onSaved={load}
        />
      </div>
    </main>
  )
}

function RolePermissionDialog({
  role,
  permissions,
  onClose,
  onSaved
}: {
  role: RoleDetail | null
  permissions: Permission[]
  onClose: () => void
  onSaved: () => Promise<void>
}) {
  const [selected, setSelected] = React.useState<string[]>([])

  React.useEffect(() => {
    setSelected(role?.permission_codes ?? [])
  }, [role])

  const groupedPermissions = React.useMemo(() => {
    return permissions.reduce<Record<string, Permission[]>>((groups, permission) => {
      groups[permission.module] = groups[permission.module] ?? []
      groups[permission.module].push(permission)
      return groups
    }, {})
  }, [permissions])

  async function handleSave() {
    if (!role) return
    await setRolePermissions(role.id, selected)
    await onSaved()
    onClose()
  }

  return (
    <Dialog open={Boolean(role)} onOpenChange={(open) => !open && onClose()}>
      <DialogContent className="sm:max-w-3xl">
        <DialogHeader>
          <DialogTitle>配置角色权限</DialogTitle>
          <DialogDescription>{role?.name} 可访问的菜单和接口能力。</DialogDescription>
        </DialogHeader>
        <div className="grid max-h-[56vh] gap-4 overflow-auto pr-1">
          {Object.entries(groupedPermissions).map(([module, modulePermissions]) => (
            <section key={module} className="rounded-md border border-border p-3">
              <p className="mb-3 text-sm font-medium text-foreground">{module}</p>
              <div className="grid gap-2 md:grid-cols-2">
                {modulePermissions.map((permission) => (
                  <label key={permission.codename} className="flex items-start gap-2 text-sm">
                    <Checkbox
                      checked={selected.includes(permission.codename)}
                      onCheckedChange={(checked) =>
                        setSelected((current) =>
                          checked
                            ? [...current, permission.codename]
                            : current.filter((code) => code !== permission.codename)
                        )
                      }
                    />
                    <span>
                      <span className="block text-foreground">{permission.name}</span>
                      <span className="text-xs text-muted-foreground">{permission.codename}</span>
                    </span>
                  </label>
                ))}
              </div>
            </section>
          ))}
        </div>
        <DialogFooter>
          <Button variant="outline" onClick={onClose}>取消</Button>
          <Button onClick={() => void handleSave()}>保存权限</Button>
        </DialogFooter>
      </DialogContent>
    </Dialog>
  )
}