import { useState, useRef, useEffect, useCallback } from 'react'
import { Search } from 'lucide-react'
import { useTasks } from '../api/tasks.ts'
import { CATEGORY_COLORS, COLUMN_CONFIG } from '../lib/constants.ts'
import type { WorkTask } from '../types/index.ts'

interface SearchBarProps {
  onSelect: (taskId: number) => void
}

export default function SearchBar({ onSelect }: SearchBarProps) {
  const { data: tasks } = useTasks()
  const [query, setQuery] = useState('')
  const [debouncedQuery, setDebouncedQuery] = useState('')
  const [isOpen, setIsOpen] = useState(false)
  const [selectedIndex, setSelectedIndex] = useState(0)
  const containerRef = useRef<HTMLDivElement>(null)
  const inputRef = useRef<HTMLInputElement>(null)
  const timerRef = useRef<ReturnType<typeof setTimeout> | null>(null)

  // Debounce the query by 200ms
  useEffect(() => {
    if (timerRef.current) clearTimeout(timerRef.current)
    timerRef.current = setTimeout(() => {
      setDebouncedQuery(query)
    }, 200)
    return () => {
      if (timerRef.current) clearTimeout(timerRef.current)
    }
  }, [query])

  // Filter tasks based on debounced query
  const results: WorkTask[] = (() => {
    if (!debouncedQuery.trim() || !tasks) return []
    const q = debouncedQuery.toLowerCase()
    return tasks
      .filter(
        (t) =>
          t.title.toLowerCase().includes(q) ||
          (t.description && t.description.toLowerCase().includes(q))
      )
      .slice(0, 8)
  })()

  // Open/close dropdown based on results
  useEffect(() => {
    setIsOpen(results.length > 0)
    setSelectedIndex(0)
  }, [results.length])

  // Close dropdown when clicking outside
  useEffect(() => {
    function handleClickOutside(e: MouseEvent) {
      if (containerRef.current && !containerRef.current.contains(e.target as Node)) {
        setIsOpen(false)
      }
    }
    document.addEventListener('mousedown', handleClickOutside)
    return () => document.removeEventListener('mousedown', handleClickOutside)
  }, [])

  const handleSelect = useCallback(
    (taskId: number) => {
      onSelect(taskId)
      setQuery('')
      setDebouncedQuery('')
      setIsOpen(false)
      inputRef.current?.blur()
    },
    [onSelect]
  )

  const handleKeyDown = useCallback(
    (e: React.KeyboardEvent) => {
      if (!isOpen) return

      switch (e.key) {
        case 'ArrowDown':
          e.preventDefault()
          setSelectedIndex((prev) => Math.min(prev + 1, results.length - 1))
          break
        case 'ArrowUp':
          e.preventDefault()
          setSelectedIndex((prev) => Math.max(prev - 1, 0))
          break
        case 'Enter':
          e.preventDefault()
          if (results[selectedIndex]) {
            handleSelect(results[selectedIndex].id)
          }
          break
        case 'Escape':
          e.preventDefault()
          setIsOpen(false)
          inputRef.current?.blur()
          break
      }
    },
    [isOpen, results, selectedIndex, handleSelect]
  )

  const getStatusLabel = (status: number) => {
    const col = COLUMN_CONFIG.find((c) => c.status === status)
    return col ? col.label : 'Unknown'
  }

  const getStatusColor = (status: number) => {
    const col = COLUMN_CONFIG.find((c) => c.status === status)
    return col ? col.color : '#64748b'
  }

  return (
    <div ref={containerRef} className="relative w-[300px]">
      <div className="relative">
        <Search
          size={16}
          className="absolute left-3 top-1/2 -translate-y-1/2 text-[#94a3b8] pointer-events-none"
        />
        <input
          ref={inputRef}
          type="text"
          value={query}
          onChange={(e) => setQuery(e.target.value)}
          onKeyDown={handleKeyDown}
          onFocus={() => {
            if (results.length > 0) setIsOpen(true)
          }}
          placeholder="Search tasks..."
          className="w-full h-8 pl-9 pr-3 rounded-full bg-[#1a1d27] text-white text-sm placeholder-[#94a3b8] border border-white/5 focus:border-indigo-500/50 focus:outline-none transition-colors"
        />
      </div>

      {isOpen && results.length > 0 && (
        <div className="absolute top-full left-0 right-0 mt-2 rounded-lg bg-[#1a1d27] border border-white/10 shadow-xl shadow-black/40 z-50 overflow-hidden">
          {results.map((task, index) => {
            const categoryColor =
              CATEGORY_COLORS[task.category ?? 'Unknown'] ?? CATEGORY_COLORS['Unknown']
            const statusColor = getStatusColor(task.status)
            const statusLabel = getStatusLabel(task.status)

            return (
              <button
                key={task.id}
                onClick={() => handleSelect(task.id)}
                onMouseEnter={() => setSelectedIndex(index)}
                className={`w-full flex items-center gap-3 px-3 py-2.5 text-left transition-colors ${
                  index === selectedIndex ? 'bg-[#2a2d37]' : ''
                }`}
              >
                {/* Status dot */}
                <span
                  className="shrink-0 w-2 h-2 rounded-full"
                  style={{ backgroundColor: statusColor }}
                  title={statusLabel}
                />

                {/* Title */}
                <span className="flex-1 text-sm text-white truncate">{task.title}</span>

                {/* Category badge */}
                {task.category && (
                  <span
                    className="shrink-0 text-[10px] font-medium px-1.5 py-0.5 rounded-full"
                    style={{
                      backgroundColor: categoryColor + '20',
                      color: categoryColor,
                    }}
                  >
                    {task.category}
                  </span>
                )}
              </button>
            )
          })}
        </div>
      )}
    </div>
  )
}