import { createContext, useContext, useEffect, useMemo, useState } from 'react'
import { Link, NavLink, Outlet, useLocation } from 'react-router-dom'
import { ChevronDown, Circle, type LucideIcon } from 'lucide-react'
import * as Icons from 'lucide-react'
import { useAuth } from '@/contexts/AuthContext'
import { TopBar } from '@/components/TopBar'
import type { MenuNode } from '@/types/menu'
import { cn } from '@/lib/cn'

function getIcon(name: string | null): LucideIcon {
  if (!name) return Circle
  const candidate = (Icons as unknown as Record<string, LucideIcon>)[name]
  return candidate ?? Circle
}

const TYPE_CODE_TO_INT: Record<string, number> = {
  ThauPhu: 1,
  GiaoKhoan: 2,
  NhaCungCap: 3,
  DichVu: 4,
  MuaBan: 5,
  NguyenTacNcc: 6,
  NguyenTacDv: 7,
}

// Reverse lookup int → code (cho auto-expand từ URL ?type=)
const INT_TO_TYPE_CODE: Record<number, string> = Object.fromEntries(
  Object.entries(TYPE_CODE_TO_INT).map(([k, v]) => [v, k]),
)

// Detect Ct_<Code> group key (no suffix, distinguish from leaf Ct_<Code>_List/Create/Pending)
const CT_GROUP_PATTERN = /^Ct_([^_]+)$/
function getCtGroupCode(key: string): string | null {
  const m = key.match(CT_GROUP_PATTERN)
  return m ? m[1] : null
}

// Pe_<Code> group key (Duyệt NCC / Duyệt NCC và Giải pháp). Riêng accordion
// để Pe_* mutex với nhau (không mix với Ct_*) — user có thể expand 1 Ct_ HĐ
// + 1 Pe_ phiếu cùng lúc vì 2 module khác nhau.
const PE_GROUP_PATTERN = /^Pe_([^_]+)$/
function getPeGroupCode(key: string): string | null {
  const m = key.match(PE_GROUP_PATTERN)
  return m ? m[1] : null
}

// PE type code → int (mirror BE PurchaseEvaluationType enum)
const PE_CODE_TO_INT: Record<string, number> = { DuyetNcc: 1, DuyetNccPhuongAn: 2 }
const INT_TO_PE_CODE: Record<number, string> = Object.fromEntries(
  Object.entries(PE_CODE_TO_INT).map(([k, v]) => [v, k]),
)

// User-side menu key → route. Differs from admin: Danh sách points to
// /my-contracts (user's own drafts), Duyệt to /inbox (pending THEIR approval).
function resolvePath(key: string): string | null {
  const staticMap: Record<string, string> = {
    Dashboard: '/dashboard',
    Contracts: '/my-contracts',
    PurchaseEvaluations: '/purchase-evaluations',
  }
  if (staticMap[key]) return staticMap[key]

  const match = key.match(/^Ct_([^_]+)_(List|Create|Pending)$/)
  if (match) {
    const [, code, action] = match
    const typeInt = TYPE_CODE_TO_INT[code]
    if (!typeInt) return null
    if (action === 'List') return `/my-contracts?type=${typeInt}`
    if (action === 'Create') return `/contracts/new?type=${typeInt}`
    if (action === 'Pending') return `/inbox?type=${typeInt}`
  }

  // Pe_<Code>_<Action> cho module Duyệt NCC (user side)
  const peMatch = key.match(/^Pe_([^_]+)_(List|Create|Pending)$/)
  if (peMatch) {
    const [, code, action] = peMatch
    const typeInt = PE_CODE_TO_INT[code]
    if (!typeInt) return null
    if (action === 'List') return `/purchase-evaluations?type=${typeInt}`
    if (action === 'Create') return `/purchase-evaluations/new?type=${typeInt}`
    if (action === 'Pending') return `/purchase-evaluations?type=${typeInt}&pendingMe=1`
  }
  return null
}

// Menu entries not applicable to user app — filtered out client-side so the
// sidebar only shows what matters to a contract drafter/approver.
const USER_HIDDEN_KEYS = new Set([
  'Master', 'Suppliers', 'Projects', 'Departments',
  'System', 'Users', 'Roles', 'Permissions',
  'Forms', 'Reports',
])

function filterForUser(nodes: MenuNode[]): MenuNode[] {
  return nodes
    .filter(n => !USER_HIDDEN_KEYS.has(n.key))
    .map(n => ({ ...n, children: filterForUser(n.children) }))
}

// Accordion state cho groups Ct_<Code> (7 HĐ) + Pe_<Code> (2 phiếu) — mỗi
// family mutex độc lập. Auto-expand theo URL `?type=X` (Ct_ dùng route
// /contracts|/my-contracts|/inbox, Pe_ dùng /purchase-evaluations). Group
// không match prefix giữ behavior cũ (independent local useState).
type AccordionContextValue = {
  expandedCtCode: string | null
  setExpandedCtCode: (code: string | null) => void
  expandedPeCode: string | null
  setExpandedPeCode: (code: string | null) => void
}
const AccordionContext = createContext<AccordionContextValue>({
  expandedCtCode: null,
  setExpandedCtCode: () => {},
  expandedPeCode: null,
  setExpandedPeCode: () => {},
})

function MenuNodeRenderer({ node, depth = 0 }: { node: MenuNode; depth?: number }) {
  const hasChildren = node.children.length > 0
  if (hasChildren) return <MenuGroup node={node} depth={depth} />
  return <MenuLeaf node={node} depth={depth} />
}

function MenuGroup({ node, depth }: { node: MenuNode; depth: number }) {
  const ctCode = getCtGroupCode(node.key)
  const peCode = getPeGroupCode(node.key)
  const accordion = useContext(AccordionContext)

  // Local state cho group thường (top-level "Hợp đồng" mặc định mở)
  const [localOpen, setLocalOpen] = useState(depth === 0)

  // Ct_<Code> / Pe_<Code> group: state controlled bởi accordion context,
  // mỗi family (Ct / Pe) mutex độc lập.
  const isCtAccordion = ctCode != null
  const isPeAccordion = peCode != null
  const isAccordion = isCtAccordion || isPeAccordion
  const open = isCtAccordion
    ? accordion.expandedCtCode === ctCode
    : isPeAccordion
      ? accordion.expandedPeCode === peCode
      : localOpen

  function toggle() {
    if (isCtAccordion) {
      accordion.setExpandedCtCode(open ? null : ctCode)
    } else if (isPeAccordion) {
      accordion.setExpandedPeCode(open ? null : peCode)
    } else {
      setLocalOpen(o => !o)
    }
  }

  const Icon = getIcon(node.icon)
  const isTopLevel = depth === 0

  return (
    <div>
      <button
        onClick={toggle}
        className={cn(
          'flex w-full items-center justify-between rounded-md transition',
          isTopLevel
            ? 'px-3 py-2 text-[11px] font-semibold uppercase tracking-wide text-slate-500 hover:bg-slate-100 whitespace-nowrap'
            : 'px-3 py-1.5 text-[13px] font-medium text-slate-600 hover:bg-slate-100 hover:text-slate-900',
          // Highlight Ct_ group đang active (accordion open) bằng tinted background
          isAccordion && open && 'bg-slate-50 text-slate-900',
        )}
      >
        <span className="flex items-center gap-2">
          <Icon className="h-4 w-4" />
          {node.label}
        </span>
        <ChevronDown className={cn('h-3.5 w-3.5 text-slate-400 transition', !open && '-rotate-90')} />
      </button>
      {open && (
        <div className={cn(
          'mt-0.5 space-y-0.5',
          depth === 0 ? 'pl-2' : 'ml-3 mt-1 border-l border-slate-100 pl-3',
        )}>
          {node.children.map(c => (
            <MenuNodeRenderer key={c.key} node={c} depth={depth + 1} />
          ))}
        </div>
      )}
    </div>
  )
}

// So sánh 2 query string dạng key-value set (thứ tự param không quan trọng).
// Dùng để distinguish /path?type=2 vs /path?type=2&pendingMe=1 — NavLink isActive
// built-in chỉ match pathname, không check query string.
function queryMatches(current: string, target: string): boolean {
  const a = new URLSearchParams(current)
  const b = new URLSearchParams(target)
  const aKeys = [...a.keys()].sort()
  const bKeys = [...b.keys()].sort()
  if (aKeys.length !== bKeys.length) return false
  return aKeys.every((k, i) => bKeys[i] === k && a.get(k) === b.get(k))
}

function MenuLeaf({ node, depth }: { node: MenuNode; depth: number }) {
  const Icon = getIcon(node.icon)
  const path = resolvePath(node.key)
  const location = useLocation()
  if (!path) return null
  const isDeep = depth >= 2

  // Custom active check: pathname match + query string match (set equality).
  // Fix bug: /purchase-evaluations?type=2 và ?type=2&pendingMe=1 cùng highlight
  // vì NavLink default chỉ check pathname.
  const [targetPath, targetQuery = ''] = path.split('?')
  const pathnameMatches = location.pathname === targetPath
  const qMatches = queryMatches(location.search.replace(/^\?/, ''), targetQuery)
  const isActive = pathnameMatches && qMatches

  return (
    <NavLink
      to={path}
      className={cn(
        'flex items-center gap-2.5 rounded-md transition',
        isDeep ? 'px-3 py-1 text-[12px]' : 'px-3 py-2 text-sm font-medium',
        isActive
          ? 'bg-brand-50 text-brand-700'
          : 'text-slate-600 hover:bg-slate-100 hover:text-slate-900',
      )}
    >
      <Icon className={cn(isDeep ? 'h-3.5 w-3.5' : 'h-4 w-4')} />
      {node.label}
    </NavLink>
  )
}

// Static entries prepended to the dynamic menu tree — these are user-app
// specific (inbox + quick create) not backed by MenuItems DB rows.
const USER_FIXED_TOP: MenuNode[] = [
  { key: '__inbox', label: 'Hộp thư', parentKey: null, order: 0, icon: 'Inbox', canRead: true, canCreate: true, canUpdate: true, canDelete: true, children: [] },
]

function staticResolvePath(key: string): string | null {
  if (key === '__inbox') return '/inbox'
  return null
}

function StaticLeaf({ node }: { node: MenuNode }) {
  const Icon = getIcon(node.icon)
  const path = staticResolvePath(node.key)
  if (!path) return null
  return (
    <NavLink
      to={path}
      end
      className={({ isActive }) =>
        cn(
          'flex items-center gap-2.5 rounded-md px-3 py-2 text-sm font-medium transition',
          isActive ? 'bg-brand-50 text-brand-700' : 'text-slate-600 hover:bg-slate-100 hover:text-slate-900',
        )
      }
    >
      <Icon className="h-4 w-4" />
      {node.label}
    </NavLink>
  )
}

export function Layout() {
  const { menu } = useAuth()
  const filteredMenu = filterForUser(menu)
  const location = useLocation()

  // Accordion state — 1 Ct_ HĐ + 1 Pe_ phiếu expand tối đa. Auto-sync theo
  // URL: /contracts|/my-contracts|/inbox?type=N → Ct, /purchase-evaluations
  // ?type=N → Pe. Khác pathname gốc → skip (không reset, giữ user choice).
  const [expandedCtCode, setExpandedCtCode] = useState<string | null>(null)
  const [expandedPeCode, setExpandedPeCode] = useState<string | null>(null)

  useEffect(() => {
    const params = new URLSearchParams(location.search)
    const typeParam = params.get('type')
    if (!typeParam) return

    const n = Number(typeParam)
    if (location.pathname.startsWith('/purchase-evaluations')) {
      const code = INT_TO_PE_CODE[n]
      if (code) setExpandedPeCode(code)
    } else {
      // /contracts, /my-contracts, /inbox, /contracts/new... — all use
      // ContractType enum
      const code = INT_TO_TYPE_CODE[n]
      if (code) setExpandedCtCode(code)
    }
  }, [location.pathname, location.search])

  const accordionValue = useMemo(
    () => ({ expandedCtCode, setExpandedCtCode, expandedPeCode, setExpandedPeCode }),
    [expandedCtCode, expandedPeCode],
  )

  return (
    <AccordionContext.Provider value={accordionValue}>
      <div className="flex h-screen">
        <aside className="flex w-72 flex-col border-r border-slate-200 bg-white">
          <div className="flex h-16 items-center border-b border-slate-200 px-5">
            <Link to="/dashboard" className="flex items-center gap-2.5">
              <img src="/logo.png" alt="Solutions" className="h-8 w-auto" />
              <span className="text-[11px] font-semibold uppercase tracking-wider text-slate-400">ERP</span>
            </Link>
          </div>
          <nav className="flex-1 space-y-1 overflow-y-auto p-3">
            {USER_FIXED_TOP.map(n => <StaticLeaf key={n.key} node={n} />)}
            {filteredMenu.map(n => (
              <MenuNodeRenderer key={n.key} node={n} depth={0} />
            ))}
          </nav>
        </aside>
        <div className="flex flex-1 flex-col overflow-hidden">
          <TopBar />
          <main className="flex-1 overflow-auto">
            <Outlet />
          </main>
        </div>
      </div>
    </AccordionContext.Provider>
  )
}
