// Users management page (US-030)

import { useState, useEffect, useCallback } from 'react'
import apiClient from '@/api/client'
import Button from '@/components/Button'
import Input from '@/components/Input'
import type { User } from '@/types'
import { formatDateTime } from '@/utils/format'

interface UserFormData {
  email: string
  name: string
  password: string
}

function UserModal({
  user,
  onClose,
  onSave,
}: {
  user: User | null
  onClose: () => void
  onSave: () => void
}) {
  const [formData, setFormData] = useState<UserFormData>({
    email: user?.email || '',
    name: user?.name || '',
    password: '',
  })
  const [isLoading, setIsLoading] = useState(false)
  const [error, setError] = useState<string | null>(null)

  const handleSubmit = async (e: React.FormEvent) => {
    e.preventDefault()
    setIsLoading(true)
    setError(null)

    try {
      if (user) {
        // Update user - only send non-empty password
        const updateData: Partial<UserFormData> = {
          name: formData.name,
        }
        if (formData.password) {
          updateData.password = formData.password
        }
        await apiClient.patch(`/users/${user.id}`, updateData)
      } else {
        // Create user
        await apiClient.post('/users', formData)
      }
      onSave()
    } catch (err) {
      setError(err instanceof Error ? err.message : 'Failed to save user')
    } finally {
      setIsLoading(false)
    }
  }

  return (
    <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/50">
      <div className="w-full max-w-md rounded-lg bg-white p-6 shadow-xl">
        <h2 className="text-xl font-semibold text-gray-900">
          {user ? 'Edit User' : 'Create User'}
        </h2>

        <form onSubmit={handleSubmit} className="mt-4 space-y-4">
          {error && (
            <div className="rounded-lg bg-red-50 px-4 py-3 text-sm text-red-700">{error}</div>
          )}

          <Input
            label="Email"
            type="email"
            name="email"
            value={formData.email}
            onChange={(e) => setFormData({ ...formData, email: e.target.value })}
            placeholder="user@example.com"
            required
            disabled={!!user}
            autoFocus={!user}
          />

          <Input
            label="Name"
            name="name"
            value={formData.name}
            onChange={(e) => setFormData({ ...formData, name: e.target.value })}
            placeholder="Full name"
            autoFocus={!!user}
          />

          <Input
            label={user ? 'New Password (leave empty to keep current)' : 'Password'}
            type="password"
            name="password"
            value={formData.password}
            onChange={(e) => setFormData({ ...formData, password: e.target.value })}
            placeholder={user ? 'Leave empty to keep current password' : 'Enter password'}
            required={!user}
          />

          <div className="flex justify-end gap-3 pt-4">
            <Button type="button" variant="secondary" onClick={onClose} disabled={isLoading}>
              Cancel
            </Button>
            <Button type="submit" isLoading={isLoading}>
              {user ? 'Save Changes' : 'Create User'}
            </Button>
          </div>
        </form>
      </div>
    </div>
  )
}

function DeleteConfirmModal({
  user,
  onClose,
  onConfirm,
}: {
  user: User
  onClose: () => void
  onConfirm: () => void
}) {
  const [isLoading, setIsLoading] = useState(false)
  const [error, setError] = useState<string | null>(null)

  const handleDelete = async () => {
    setIsLoading(true)
    setError(null)

    try {
      await apiClient.delete(`/users/${user.id}`)
      onConfirm()
    } catch (err) {
      setError(err instanceof Error ? err.message : 'Failed to delete user')
      setIsLoading(false)
    }
  }

  return (
    <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/50">
      <div className="w-full max-w-md rounded-lg bg-white p-6 shadow-xl">
        <h2 className="text-xl font-semibold text-gray-900">Delete User</h2>
        <p className="mt-2 text-gray-600">
          Are you sure you want to delete <strong>{user.name || user.email}</strong>? This action
          cannot be undone.
        </p>

        {error && (
          <div className="mt-4 rounded-lg bg-red-50 px-4 py-3 text-sm text-red-700">{error}</div>
        )}

        <div className="mt-6 flex justify-end gap-3">
          <Button type="button" variant="secondary" onClick={onClose} disabled={isLoading}>
            Cancel
          </Button>
          <Button type="button" variant="danger" onClick={handleDelete} isLoading={isLoading}>
            Delete User
          </Button>
        </div>
      </div>
    </div>
  )
}

function Users() {
  const [users, setUsers] = useState<User[]>([])
  const [filteredUsers, setFilteredUsers] = useState<User[]>([])
  const [isLoading, setIsLoading] = useState(true)
  const [error, setError] = useState<string | null>(null)
  const [searchQuery, setSearchQuery] = useState('')
  const [showCreateModal, setShowCreateModal] = useState(false)
  const [editingUser, setEditingUser] = useState<User | null>(null)
  const [deletingUser, setDeletingUser] = useState<User | null>(null)

  const fetchUsers = useCallback(async () => {
    setIsLoading(true)
    setError(null)
    try {
      // Always fetch all users - this is a system-level user management page
      const response = await apiClient.get<{ users?: User[] }>('/users')
      setUsers(response.users || [])
    } catch (err) {
      setError(err instanceof Error ? err.message : 'Failed to fetch users')
    } finally {
      setIsLoading(false)
    }
  }, [])

  useEffect(() => {
    fetchUsers()
  }, [fetchUsers])

  useEffect(() => {
    const query = searchQuery.toLowerCase()
    setFilteredUsers(
      users.filter(
        (u) =>
          u.email.toLowerCase().includes(query) ||
          (u.name && u.name.toLowerCase().includes(query)) ||
          u.id.toLowerCase().includes(query)
      )
    )
  }, [users, searchQuery])

  const handleSave = () => {
    setShowCreateModal(false)
    setEditingUser(null)
    fetchUsers()
  }

  const handleDelete = () => {
    setDeletingUser(null)
    fetchUsers()
  }

  return (
    <div className="space-y-6">
      <div className="flex flex-col gap-4 sm:flex-row sm:items-center sm:justify-between">
        <div>
          <h1 className="text-2xl font-bold text-gray-900">Users</h1>
          <p className="mt-1 text-gray-600">Manage all users in the system</p>
        </div>
        <Button onClick={() => setShowCreateModal(true)}>
          <svg className="-ml-1 mr-2 h-5 w-5" fill="none" viewBox="0 0 24 24" stroke="currentColor">
            <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M12 4v16m8-8H4" />
          </svg>
          Create User
        </Button>
      </div>

      {/* Search */}
      <div className="max-w-md">
        <Input
          type="search"
          placeholder="Search users..."
          value={searchQuery}
          onChange={(e) => setSearchQuery(e.target.value)}
        />
      </div>

      {/* Error state */}
      {error && <div className="rounded-lg bg-red-50 px-4 py-3 text-sm text-red-700">{error}</div>}

      {/* Loading state */}
      {isLoading && (
        <div className="flex items-center justify-center py-12">
          <svg
            className="h-8 w-8 animate-spin text-primary-600"
            xmlns="http://www.w3.org/2000/svg"
            fill="none"
            viewBox="0 0 24 24"
          >
            <circle
              className="opacity-25"
              cx="12"
              cy="12"
              r="10"
              stroke="currentColor"
              strokeWidth="4"
            />
            <path
              className="opacity-75"
              fill="currentColor"
              d="M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4zm2 5.291A7.962 7.962 0 014 12H0c0 3.042 1.135 5.824 3 7.938l3-2.647z"
            />
          </svg>
        </div>
      )}

      {/* User list */}
      {!isLoading && !error && (
        <div className="overflow-hidden rounded-lg bg-white shadow">
          {filteredUsers.length === 0 ? (
            <div className="px-6 py-12 text-center">
              <p className="text-gray-500">
                {searchQuery ? 'No users match your search' : 'No users found'}
              </p>
            </div>
          ) : (
            <table className="min-w-full divide-y divide-gray-200">
              <thead className="bg-gray-50">
                <tr>
                  <th className="px-6 py-3 text-left text-xs font-medium uppercase tracking-wider text-gray-500">
                    User
                  </th>
                  <th className="px-6 py-3 text-left text-xs font-medium uppercase tracking-wider text-gray-500">
                    ID
                  </th>
                  <th className="px-6 py-3 text-left text-xs font-medium uppercase tracking-wider text-gray-500">
                    Created
                  </th>
                  <th className="px-6 py-3 text-left text-xs font-medium uppercase tracking-wider text-gray-500">
                    Updated
                  </th>
                  <th className="px-6 py-3 text-right text-xs font-medium uppercase tracking-wider text-gray-500">
                    Actions
                  </th>
                </tr>
              </thead>
              <tbody className="divide-y divide-gray-200 bg-white">
                {filteredUsers.map((user) => (
                  <tr key={user.id} className="hover:bg-gray-50">
                    <td className="whitespace-nowrap px-6 py-4">
                      <div className="flex items-center">
                        <div className="flex h-10 w-10 items-center justify-center rounded-full bg-primary-100 text-primary-700">
                          {user.name?.[0]?.toUpperCase() || user.email[0].toUpperCase()}
                        </div>
                        <div className="ml-4">
                          <div className="font-medium text-gray-900">{user.name || 'No name'}</div>
                          <div className="text-sm text-gray-500">{user.email}</div>
                        </div>
                      </div>
                    </td>
                    <td className="whitespace-nowrap px-6 py-4">
                      <code className="rounded bg-gray-100 px-2 py-1 text-sm text-gray-600">
                        {user.id.slice(0, 8)}...
                      </code>
                    </td>
                    <td className="px-6 py-4 text-sm text-gray-500">
                      <div>{formatDateTime(user.created_at)}</div>
                      {user.created_by_name && (
                        <div className="text-xs text-gray-400">by {user.created_by_name}</div>
                      )}
                    </td>
                    <td className="px-6 py-4 text-sm text-gray-500">
                      <div>{formatDateTime(user.updated_at)}</div>
                      {user.updated_by_name && (
                        <div className="text-xs text-gray-400">by {user.updated_by_name}</div>
                      )}
                    </td>
                    <td className="whitespace-nowrap px-6 py-4 text-right">
                      <div className="flex justify-end gap-2">
                        <button
                          onClick={() => setEditingUser(user)}
                          className="rounded px-3 py-1 text-sm text-primary-600 hover:bg-primary-50"
                        >
                          Edit
                        </button>
                        <button
                          onClick={() => setDeletingUser(user)}
                          className="rounded px-3 py-1 text-sm text-red-600 hover:bg-red-50"
                        >
                          Delete
                        </button>
                      </div>
                    </td>
                  </tr>
                ))}
              </tbody>
            </table>
          )}
        </div>
      )}

      {/* Modals */}
      {showCreateModal && (
        <UserModal user={null} onClose={() => setShowCreateModal(false)} onSave={handleSave} />
      )}
      {editingUser && (
        <UserModal user={editingUser} onClose={() => setEditingUser(null)} onSave={handleSave} />
      )}
      {deletingUser && (
        <DeleteConfirmModal
          user={deletingUser}
          onClose={() => setDeletingUser(null)}
          onConfirm={handleDelete}
        />
      )}
    </div>
  )
}

export default Users