import { useCallback, useEffect, useState } from 'react'
import { useNavigate, useParams } from 'react-router-dom'
import {
  ArrowLeft,
  Building2,
  CalendarClock,
  Check,
  Copy,
  Crown,
  Loader2,
  Mail,
  Pencil,
  UserCheck,
  UserPlus,
  UserX,
  X,
} from 'lucide-react'
import { Button } from '@/components/ui/Button'
import { Input } from '@/components/ui/Input'
import { Modal } from '@/components/common/Modal'
import { EmptyState, StatusBadge } from '@/components/admin'
import { ConfirmButton } from '@/components/common/ConfirmButton'
import { adminApi } from '@/api/admin'
import { toast } from '@/lib/toast'
import { cn } from '@/lib/utils'
import type { AdminAccountDetailResponse, AdminAccountMember } from '@/types/admin'

function formatDate(value: string | null) {
  if (!value) return 'Never'
  return new Date(value).toLocaleDateString()
}

export function AccountDetailPage() {
  const { accountId } = useParams<{ accountId: string }>()
  const navigate = useNavigate()

  const [account, setAccount] = useState<AdminAccountDetailResponse | null>(null)
  const [loading, setLoading] = useState(true)
  const [isEditingName, setIsEditingName] = useState(false)
  const [editedName, setEditedName] = useState('')
  const [savingName, setSavingName] = useState(false)

  const [showCreateUserModal, setShowCreateUserModal] = useState(false)
  const [createForm, setCreateForm] = useState({
    email: '',
    name: '',
    account_role: 'engineer' as 'owner' | 'admin' | 'engineer' | 'viewer',
    send_email: true,
  })
  const [createLoading, setCreateLoading] = useState(false)
  const [tempPassword, setTempPassword] = useState<string | null>(null)
  const [copiedPassword, setCopiedPassword] = useState(false)

  const [showInviteModal, setShowInviteModal] = useState(false)
  const [inviteForm, setInviteForm] = useState({
    email: '',
    role: 'engineer' as 'engineer' | 'viewer',
  })
  const [inviteLoading, setInviteLoading] = useState(false)

  const [editingPlan, setEditingPlan] = useState(false)
  const [selectedPlan, setSelectedPlan] = useState('free')
  const [planSaving, setPlanSaving] = useState(false)

  const [editingTrial, setEditingTrial] = useState(false)
  const [trialDays, setTrialDays] = useState('14')
  const [trialSaving, setTrialSaving] = useState(false)

  const loadAccount = useCallback(async () => {
    if (!accountId) return
    setLoading(true)
    try {
      const data = await adminApi.getAccountDetail(accountId)
      setAccount(data)
      setEditedName(data.name)
      setSelectedPlan(data.subscription?.plan ?? 'free')
    } catch {
      toast.error('Failed to load account')
    } finally {
      setLoading(false)
    }
  }, [accountId])

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

  const handleSaveName = async () => {
    if (!account || !editedName.trim() || editedName.trim() === account.name) {
      setIsEditingName(false)
      return
    }
    setSavingName(true)
    try {
      const updated = await adminApi.updateAccount(account.id, { name: editedName.trim() })
      setAccount(updated)
      setEditedName(updated.name)
      setIsEditingName(false)
      toast.success('Account updated')
    } catch {
      toast.error('Failed to update account')
    } finally {
      setSavingName(false)
    }
  }

  const handleCreateUser = async () => {
    if (!account || !createForm.email || !createForm.name) return
    setCreateLoading(true)
    try {
      const result = await adminApi.createUser({
        email: createForm.email,
        name: createForm.name,
        account_mode: 'existing',
        account_display_code: account.display_code,
        account_role: createForm.account_role,
        send_email: createForm.send_email,
      })
      setShowCreateUserModal(false)
      setCreateForm({ email: '', name: '', account_role: 'engineer' as 'owner' | 'admin' | 'engineer' | 'viewer', send_email: true })
      setTempPassword(result.temporary_password)
      setCopiedPassword(false)
      toast.success(result.email_sent ? 'User created and welcome email sent' : 'User created')
      loadAccount()
    } catch (err: unknown) {
      if (err && typeof err === 'object' && 'response' in err) {
        const axiosErr = err as { response?: { data?: { detail?: string } } }
        toast.error(axiosErr.response?.data?.detail || 'Failed to create user')
      } else {
        toast.error('Failed to create user')
      }
    } finally {
      setCreateLoading(false)
    }
  }

  const handleInviteUser = async () => {
    if (!account || !inviteForm.email) return
    setInviteLoading(true)
    try {
      await adminApi.createInvite({
        email: inviteForm.email,
        account_display_code: account.display_code,
        role: inviteForm.role,
      })
      toast.success('Invite sent')
      setInviteForm({ email: '', role: 'engineer' })
      setShowInviteModal(false)
      loadAccount()
    } catch (err: unknown) {
      if (err && typeof err === 'object' && 'response' in err) {
        const axiosErr = err as { response?: { data?: { detail?: string } } }
        toast.error(axiosErr.response?.data?.detail || 'Failed to send invite')
      } else {
        toast.error('Failed to send invite')
      }
    } finally {
      setInviteLoading(false)
    }
  }

  const handleUpdateMemberRole = async (member: AdminAccountMember, nextRole: string) => {
    try {
      await adminApi.updateAccountRole(member.id, nextRole)
      toast.success(`Updated ${member.name}`)
      loadAccount()
    } catch {
      toast.error('Failed to update account role')
    }
  }

  const handleToggleActive = async (member: AdminAccountMember) => {
    try {
      if (member.is_active) {
        await adminApi.deactivateUser(member.id)
        toast.success('User deactivated')
      } else {
        await adminApi.activateUser(member.id)
        toast.success('User activated')
      }
      loadAccount()
    } catch {
      toast.error('Failed to update user status')
    }
  }

  const handleUpdatePlan = async () => {
    if (!account) return
    setPlanSaving(true)
    try {
      await adminApi.updateAccountSubscriptionPlan(account.id, selectedPlan)
      toast.success(`Plan updated to ${selectedPlan}`)
      setEditingPlan(false)
      loadAccount()
    } catch {
      toast.error('Failed to update plan')
    } finally {
      setPlanSaving(false)
    }
  }

  const handleExtendTrial = async () => {
    if (!account || !trialDays) return
    setTrialSaving(true)
    try {
      await adminApi.extendAccountTrial(account.id, parseInt(trialDays, 10))
      toast.success(`Trial updated by ${trialDays} days`)
      setEditingTrial(false)
      loadAccount()
    } catch {
      toast.error('Failed to update trial')
    } finally {
      setTrialSaving(false)
    }
  }

  const copyDisplayCode = async () => {
    if (!account) return
    await navigator.clipboard.writeText(account.display_code)
    toast.success('Display code copied')
  }

  const copyTempPassword = async () => {
    if (!tempPassword) return
    await navigator.clipboard.writeText(tempPassword)
    setCopiedPassword(true)
    setTimeout(() => setCopiedPassword(false), 2000)
  }

  if (loading) {
    return (
      <div className="flex items-center justify-center py-20">
        <Loader2 className="h-8 w-8 animate-spin text-muted-foreground" />
      </div>
    )
  }

  if (!account) {
    return (
      <EmptyState
        title="Account not found"
        description="This account may have been removed or is unavailable."
        action={<Button variant="secondary" onClick={() => navigate('/admin/accounts')}>Back to Accounts</Button>}
      />
    )
  }

  return (
    <div className="space-y-6">
      <div className="flex items-center gap-4">
        <button
          onClick={() => navigate('/admin/accounts')}
          className="rounded-md border border-border p-2 text-muted-foreground hover:bg-elevated hover:text-foreground"
        >
          <ArrowLeft className="h-4 w-4" />
        </button>
        <div className="min-w-0 flex-1">
          <div className="flex items-center gap-3">
            <Building2 className="h-6 w-6 text-muted-foreground" />
            <h1 className="truncate text-2xl font-bold text-foreground">{account.name}</h1>
            <StatusBadge variant="default" title="Unique code for joining this account">{account.display_code}</StatusBadge>
          </div>
          <p className="mt-1 text-sm text-muted-foreground">
            Manage account settings, subscription, invites, and users from one place.
          </p>
        </div>
        <div className="flex gap-3">
          <Button variant="secondary" onClick={() => setShowInviteModal(true)}>
            <Mail className="h-4 w-4" />
            Invite User
          </Button>
          <Button onClick={() => setShowCreateUserModal(true)}>
            <UserPlus className="h-4 w-4" />
            Create User
          </Button>
        </div>
      </div>

      <div className="grid gap-6 xl:grid-cols-[1.1fr_0.9fr]">
        <section className="space-y-6">
          <div className="rounded-2xl border border-border bg-card p-5">
            <div className="flex items-center justify-between gap-4">
              <h2 className="text-lg font-semibold text-foreground">Account Settings</h2>
              <Button variant="secondary" size="sm" onClick={copyDisplayCode}>
                <Copy className="h-4 w-4" />
                Copy Code
              </Button>
            </div>

            <div className="mt-5 space-y-5">
              <div>
                <label className="block text-sm font-medium text-foreground">Account Name</label>
                {isEditingName ? (
                  <div className="mt-2 flex items-center gap-2">
                    <Input value={editedName} onChange={(e) => setEditedName(e.target.value)} />
                    <Button onClick={handleSaveName} loading={savingName} size="icon-sm">
                      <Check className="h-4 w-4" />
                    </Button>
                    <Button
                      variant="secondary"
                      size="icon-sm"
                      onClick={() => {
                        setEditedName(account.name)
                        setIsEditingName(false)
                      }}
                    >
                      <X className="h-4 w-4" />
                    </Button>
                  </div>
                ) : (
                  <div className="mt-2 flex items-center gap-2">
                    <span className="text-sm text-foreground">{account.name}</span>
                    <button
                      onClick={() => setIsEditingName(true)}
                      className="rounded px-1.5 py-0.5 text-xs text-muted-foreground transition-colors hover:bg-muted hover:text-foreground"
                    >
                      <Pencil className="h-3.5 w-3.5" />
                    </button>
                  </div>
                )}
              </div>

              <div className="grid gap-4 sm:grid-cols-2">
                <div className="rounded-xl border border-border bg-card/50 p-4">
                  <p className="text-xs uppercase tracking-[0.14em] text-muted-foreground">Owner</p>
                  <p className="mt-2 text-sm text-foreground">{account.owner?.name ?? 'Unassigned'}</p>
                  <p className="text-xs text-muted-foreground">{account.owner?.email ?? 'No owner user yet'}</p>
                </div>
                <div className="rounded-xl border border-border bg-card/50 p-4">
                  <p className="text-xs uppercase tracking-[0.14em] text-muted-foreground">Created</p>
                  <p className="mt-2 text-sm text-foreground">{formatDate(account.created_at)}</p>
                </div>
              </div>
            </div>
          </div>

          <div className="rounded-2xl border border-border bg-card p-5">
            <div className="flex items-center justify-between gap-4">
              <h2 className="text-lg font-semibold text-foreground">Users</h2>
              <StatusBadge variant="default">{account.member_count} members</StatusBadge>
            </div>

            <div className="mt-4 space-y-3">
              {account.members.length > 0 ? (
                account.members.map((member) => (
                  <div key={member.id} className="rounded-xl border border-border bg-card/50 p-4">
                    <div className="flex flex-col gap-3 md:flex-row md:items-center md:justify-between">
                      <div>
                        <p className="font-medium text-foreground">{member.name}</p>
                        <p className="text-sm text-muted-foreground">{member.email}</p>
                        <div className="mt-2 flex flex-wrap gap-2">
                          <StatusBadge variant="default">{member.role}</StatusBadge>
                          {member.account_role && <StatusBadge variant="default">{member.account_role}</StatusBadge>}
                          <StatusBadge variant={member.is_active ? 'success' : 'destructive'}>
                            {member.is_active ? 'Active' : 'Inactive'}
                          </StatusBadge>
                        </div>
                      </div>
                      <div className="flex flex-wrap items-center gap-2">
                        <select
                          value={member.account_role ?? 'engineer'}
                          onChange={(e) => handleUpdateMemberRole(member, e.target.value)}
                          className={cn(
                            'rounded-md border border-border bg-card px-3 py-2 text-sm text-foreground',
                            'focus:outline-hidden focus:border-primary focus:ring-2 focus:ring-primary/20'
                          )}
                        >
                          <option value="owner">Owner</option>
                          <option value="admin">Admin</option>
                          <option value="engineer">Engineer</option>
                          <option value="viewer">Viewer</option>
                        </select>
                        {member.is_active ? (
                          <ConfirmButton
                            onConfirm={() => handleToggleActive(member)}
                            confirmLabel="Confirm deactivate?"
                            className="inline-flex items-center gap-1.5 rounded-md border border-border bg-card px-3 py-1.5 text-sm font-medium text-foreground transition-colors hover:bg-elevated"
                            confirmClassName="inline-flex items-center rounded-md border border-danger/30 bg-danger-dim px-3 py-1.5 text-sm font-medium text-danger transition-colors"
                          >
                            <UserX className="h-4 w-4" />
                            Deactivate
                          </ConfirmButton>
                        ) : (
                          <Button variant="secondary" size="sm" onClick={() => handleToggleActive(member)}>
                            <UserCheck className="h-4 w-4" />
                            Activate
                          </Button>
                        )}
                        <Button variant="secondary" size="sm" onClick={() => navigate(`/admin/users/${member.id}`)}>
                          View User
                        </Button>
                      </div>
                    </div>
                  </div>
                ))
              ) : (
                <div className="rounded-xl border border-dashed border-border px-4 py-6 text-center text-sm text-muted-foreground">
                  <p>No users yet.</p>
                  <p className="mt-1">Use <strong className="text-foreground">Create User</strong> or <strong className="text-foreground">Invite User</strong> above to add members.</p>
                </div>
              )}
            </div>
          </div>
        </section>

        <aside className="space-y-6">
          <div className="rounded-2xl border border-border bg-card p-5">
            <div className="flex items-center justify-between gap-3">
              <h2 className="text-lg font-semibold text-foreground">Subscription</h2>
              {account.subscription ? (
                <div className="flex gap-2">
                  <StatusBadge variant="default">{account.subscription.plan}</StatusBadge>
                  <StatusBadge variant={account.subscription.status === 'active' ? 'success' : account.subscription.status === 'canceled' ? 'destructive' : 'warning'}>
                    {account.subscription.status}
                  </StatusBadge>
                </div>
              ) : (
                <StatusBadge variant="warning">No subscription</StatusBadge>
              )}
            </div>

            <div className="mt-4 grid gap-3 sm:grid-cols-2">
              <div className="rounded-xl border border-border bg-card/50 p-4">
                <p className="text-xs uppercase tracking-[0.14em] text-muted-foreground">Renewal</p>
                <p className="mt-2 text-sm text-foreground">{formatDate(account.subscription?.current_period_end ?? null)}</p>
              </div>
              <div className="rounded-xl border border-border bg-card/50 p-4">
                <p className="text-xs uppercase tracking-[0.14em] text-muted-foreground">Usage</p>
                <p className="mt-2 text-sm text-foreground">{account.usage.tree_count} flows · {account.usage.session_count_this_month} sessions</p>
              </div>
            </div>

            {editingPlan ? (
              <div className="mt-4 flex items-center gap-2">
                <select
                  value={selectedPlan}
                  onChange={(e) => setSelectedPlan(e.target.value)}
                  className={cn(
                    'h-9 rounded-md border border-border bg-card px-3 text-sm text-foreground',
                    'focus:outline-hidden focus:border-primary focus:ring-2 focus:ring-primary/20'
                  )}
                >
                  <option value="free">Free</option>
                  <option value="pro">Pro</option>
                  <option value="team">Team</option>
                </select>
                <Button size="sm" onClick={handleUpdatePlan} loading={planSaving}>Save</Button>
                <Button variant="secondary" size="sm" onClick={() => setEditingPlan(false)}>Cancel</Button>
              </div>
            ) : editingTrial ? (
              <div className="mt-4 flex items-center gap-2">
                <Input
                  type="number"
                  min={1}
                  max={90}
                  value={trialDays}
                  onChange={(e) => setTrialDays(e.target.value)}
                  className="w-24"
                  placeholder="Days"
                />
                <Button size="sm" onClick={handleExtendTrial} loading={trialSaving}>Save</Button>
                <Button variant="secondary" size="sm" onClick={() => setEditingTrial(false)}>Cancel</Button>
              </div>
            ) : (
              <div className="mt-4 flex flex-wrap gap-2">
                <Button
                  variant="secondary"
                  size="sm"
                  onClick={() => {
                    setSelectedPlan(account.subscription?.plan ?? 'free')
                    setEditingPlan(true)
                  }}
                >
                  <Crown className="h-4 w-4" />
                  Change Plan
                </Button>
                <Button
                  variant="secondary"
                  size="sm"
                  onClick={() => {
                    setTrialDays('14')
                    setEditingTrial(true)
                  }}
                >
                  <CalendarClock className="h-4 w-4" />
                  Extend Trial
                </Button>
              </div>
            )}
          </div>

          <div className="rounded-2xl border border-border bg-card p-5">
            <div className="flex items-center justify-between gap-3">
              <h2 className="text-lg font-semibold text-foreground">Pending Invites</h2>
              {account.pending_invite_count > 0 && (
                <StatusBadge variant="warning">{account.pending_invite_count} pending</StatusBadge>
              )}
            </div>
            <div className="mt-4 space-y-3">
              {account.invites.length > 0 ? (
                account.invites.map((invite) => (
                  <div key={invite.id} className="rounded-xl border border-border bg-card/50 p-4">
                    <p className="font-medium text-foreground">{invite.email}</p>
                    <div className="mt-2 flex flex-wrap gap-2">
                      <StatusBadge variant="default">{invite.role}</StatusBadge>
                      <StatusBadge variant="default">Expires {formatDate(invite.expires_at)}</StatusBadge>
                    </div>
                  </div>
                ))
              ) : (
                <div className="rounded-xl border border-dashed border-border px-4 py-6 text-center text-sm text-muted-foreground">
                  <p>No pending invites.</p>
                  <p className="mt-1">Use <strong className="text-foreground">Invite User</strong> above to send an invitation.</p>
                </div>
              )}
            </div>
          </div>
        </aside>
      </div>

      <Modal
        isOpen={showCreateUserModal}
        onClose={() => setShowCreateUserModal(false)}
        title="Create User in Account"
        size="sm"
        footer={(
          <div className="flex justify-end gap-3">
            <Button variant="secondary" onClick={() => setShowCreateUserModal(false)}>Cancel</Button>
            <Button onClick={handleCreateUser} disabled={!createForm.email || !createForm.name} loading={createLoading}>
              {createLoading ? 'Creating...' : 'Create User'}
            </Button>
          </div>
        )}
      >
        <div className="space-y-4">
          <div>
            <label className="mb-1 block text-sm font-medium text-foreground">Name</label>
            <Input value={createForm.name} onChange={(e) => setCreateForm((f) => ({ ...f, name: e.target.value }))} />
          </div>
          <div>
            <label className="mb-1 block text-sm font-medium text-foreground">Email</label>
            <Input type="email" value={createForm.email} onChange={(e) => setCreateForm((f) => ({ ...f, email: e.target.value }))} />
          </div>
          <div>
            <label className="mb-1 block text-sm font-medium text-foreground">Account Role</label>
            <select
              value={createForm.account_role}
              onChange={(e) => setCreateForm((f) => ({ ...f, account_role: e.target.value as 'owner' | 'admin' | 'engineer' | 'viewer' }))}
              className={cn(
                'w-full rounded-md border border-border bg-card px-3 py-2 text-sm text-foreground',
                'focus:outline-hidden focus:border-primary focus:ring-2 focus:ring-primary/20'
              )}
            >
              <option value="owner">Owner</option>
              <option value="admin">Admin</option>
              <option value="engineer">Engineer</option>
              <option value="viewer">Viewer</option>
            </select>
          </div>
          <div className="flex items-center gap-2">
            <input
              type="checkbox"
              checked={createForm.send_email}
              onChange={(e) => setCreateForm((f) => ({ ...f, send_email: e.target.checked }))}
              className="rounded border-border bg-card"
            />
            <label className="text-sm text-muted-foreground">Send welcome email with temporary password</label>
          </div>
        </div>
      </Modal>

      <Modal
        isOpen={showInviteModal}
        onClose={() => setShowInviteModal(false)}
        title="Invite User to Account"
        size="sm"
        footer={(
          <div className="flex justify-end gap-3">
            <Button variant="secondary" onClick={() => setShowInviteModal(false)}>Cancel</Button>
            <Button onClick={handleInviteUser} disabled={!inviteForm.email} loading={inviteLoading}>
              {inviteLoading ? 'Sending...' : 'Send Invite'}
            </Button>
          </div>
        )}
      >
        <div className="space-y-4">
          <div>
            <label className="mb-1 block text-sm font-medium text-foreground">Email</label>
            <Input type="email" value={inviteForm.email} onChange={(e) => setInviteForm((f) => ({ ...f, email: e.target.value }))} />
          </div>
          <div>
            <label className="mb-1 block text-sm font-medium text-foreground">Role</label>
            <select
              value={inviteForm.role}
              onChange={(e) => setInviteForm((f) => ({ ...f, role: e.target.value as 'engineer' | 'viewer' }))}
              className={cn(
                'w-full rounded-md border border-border bg-card px-3 py-2 text-sm text-foreground',
                'focus:outline-hidden focus:border-primary focus:ring-2 focus:ring-primary/20'
              )}
            >
              <option value="engineer">Engineer</option>
              <option value="viewer">Viewer</option>
            </select>
          </div>
        </div>
      </Modal>

      <Modal
        isOpen={!!tempPassword}
        onClose={() => setTempPassword(null)}
        title="User Created"
        size="sm"
        footer={<div className="flex justify-end"><Button onClick={() => setTempPassword(null)}>Done</Button></div>}
      >
        <div className="space-y-4">
          <div className="rounded-xl border border-yellow-400/20 bg-yellow-400/10 p-3 text-sm text-yellow-400">
            This password will not be shown again. Copy it now.
          </div>
          <div className="flex items-center gap-2">
            <code className="flex-1 rounded-md border border-border bg-card px-3 py-2 font-mono text-sm text-foreground">
              {tempPassword}
            </code>
            <button
              onClick={copyTempPassword}
              className="rounded-md border border-border p-2 text-muted-foreground transition-colors hover:bg-elevated hover:text-foreground"
            >
              {copiedPassword ? <Check className="h-4 w-4 text-green-400" /> : <Copy className="h-4 w-4" />}
            </button>
          </div>
        </div>
      </Modal>

    </div>
  )
}

export default AccountDetailPage