import React, { useState, useRef, useEffect } from 'react'
import ReactDOM from 'react-dom'
import { Clock, ChevronUp, ChevronDown } from 'lucide-react'
import { useSettingsStore } from '../../store/settingsStore'

function formatDisplay(val: string, is12h: boolean): string {
  if (!val) return ''
  const [h, m] = val.split(':').map(Number)
  if (isNaN(h) || isNaN(m)) return val
  if (!is12h) return val
  const period = h >= 12 ? 'PM' : 'AM'
  const h12 = h === 0 ? 12 : h > 12 ? h - 12 : h
  return `${h12}:${String(m).padStart(2, '0')} ${period}`
}

interface CustomTimePickerProps {
  value: string
  onChange: (value: string) => void
  placeholder?: string
  style?: React.CSSProperties
}

export default function CustomTimePicker({ value, onChange, placeholder = '00:00', style = {} }: CustomTimePickerProps) {
  const is12h = useSettingsStore(s => s.settings.time_format) === '12h'
  const [open, setOpen] = useState(false)
  const [inputFocused, setInputFocused] = useState(false)
  const ref = useRef<HTMLDivElement>(null)
  const dropRef = useRef<HTMLDivElement>(null)

  const [h, m] = (value || '').split(':').map(Number)
  const hour = isNaN(h) ? null : h
  const minute = isNaN(m) ? null : m

  useEffect(() => {
    const handler = (e: MouseEvent) => {
      if (ref.current?.contains(e.target as Node)) return
      if (dropRef.current?.contains(e.target as Node)) return
      setOpen(false)
    }
    if (open) document.addEventListener('mousedown', handler)
    return () => document.removeEventListener('mousedown', handler)
  }, [open])

  const update = (newH: number, newM: number) => {
    const hh = String(Math.max(0, Math.min(23, newH))).padStart(2, '0')
    const mm = String(Math.max(0, Math.min(59, newM))).padStart(2, '0')
    onChange(`${hh}:${mm}`)
  }

  const incHour = () => update(((hour ?? -1) + 1) % 24, minute ?? 0)
  const decHour = () => update(((hour ?? 1) - 1 + 24) % 24, minute ?? 0)
  const incMin = () => {
    const newM = ((minute ?? -5) + 5) % 60
    const newH = newM < (minute ?? 0) ? ((hour ?? 0) + 1) % 24 : (hour ?? 0)
    update(newH, newM)
  }
  const decMin = () => {
    const newM = ((minute ?? 5) - 5 + 60) % 60
    const newH = newM > (minute ?? 0) ? ((hour ?? 0) - 1 + 24) % 24 : (hour ?? 0)
    update(newH, newM)
  }

  const btnStyle: React.CSSProperties = {
    background: 'none', border: 'none', cursor: 'pointer', padding: 2,
    color: 'var(--text-faint)', display: 'flex', borderRadius: 4,
    transition: 'color 0.15s',
  }

  const handleInput = (e: React.ChangeEvent<HTMLInputElement>) => {
    const raw = e.target.value
    onChange(raw)
    if (is12h) return // let handleBlur parse 12h formats
    const clean = raw.replace(/[^0-9:]/g, '')
    if (/^\d{2}:\d{2}$/.test(clean)) onChange(clean)
    else if (/^\d{4}$/.test(clean)) onChange(clean.slice(0, 2) + ':' + clean.slice(2))
    else if (/^\d{1,2}:\d{2}$/.test(clean)) {
      const [hh, mm] = clean.split(':')
      onChange(hh.padStart(2, '0') + ':' + mm)
    }
  }

  const handleBlur = () => {
    if (!value) return
    const raw = value.trim()

    // Parse 12h input like "5:30 PM", "5:30pm", "530pm"
    if (is12h) {
      const match12 = raw.match(/^(\d{1,2}):?(\d{2})?\s*(am|pm)$/i)
      if (match12) {
        let h = parseInt(match12[1])
        const m = match12[2] ? parseInt(match12[2]) : 0
        const isPm = match12[3].toLowerCase() === 'pm'
        if (h === 12) h = isPm ? 12 : 0
        else if (isPm) h += 12
        onChange(String(Math.min(23, h)).padStart(2, '0') + ':' + String(Math.min(59, m)).padStart(2, '0'))
        return
      }
    }

    const clean = raw.replace(/[^0-9:]/g, '')
    if (/^\d{1,2}:\d{2}$/.test(clean)) {
      const [hh, mm] = clean.split(':')
      const h = Math.min(23, Math.max(0, parseInt(hh)))
      const m = Math.min(59, Math.max(0, parseInt(mm)))
      onChange(String(h).padStart(2, '0') + ':' + String(m).padStart(2, '0'))
    } else if (/^\d{3,4}$/.test(clean)) {
      const s = clean.padStart(4, '0')
      const h = Math.min(23, Math.max(0, parseInt(s.slice(0, 2))))
      const m = Math.min(59, Math.max(0, parseInt(s.slice(2))))
      onChange(String(h).padStart(2, '0') + ':' + String(m).padStart(2, '0'))
    } else if (/^\d{1,2}$/.test(clean)) {
      const h = Math.min(23, Math.max(0, parseInt(clean)))
      onChange(String(h).padStart(2, '0') + ':00')
    }
  }

  return (
    <div ref={ref} style={{ position: 'relative', ...style }}>
      <div style={{
        width: '100%', display: 'flex', alignItems: 'center', gap: 0,
        borderRadius: 10, border: '1px solid var(--border-primary)',
        background: 'var(--bg-input)', overflow: 'hidden',
        transition: 'border-color 0.15s',
      }}>
        <input
          type="text"
          value={inputFocused ? value : formatDisplay(value, is12h)}
          onChange={handleInput}
          onFocus={() => setInputFocused(true)}
          onBlur={() => { setInputFocused(false); handleBlur() }}
          placeholder={is12h ? '2:30 PM' : placeholder}
          style={{
            flex: 1, border: 'none', outline: 'none', background: 'transparent',
            padding: '8px 10px 8px 14px', fontSize: 13, fontFamily: 'inherit',
            color: value ? 'var(--text-primary)' : 'var(--text-faint)',
            minWidth: 0,
          }}
        />
        <button
          type="button"
          onClick={() => setOpen(o => !o)}
          style={{
            background: 'none', border: 'none', cursor: 'pointer', padding: '8px 10px',
            display: 'flex', alignItems: 'center', color: 'var(--text-faint)',
            transition: 'color 0.15s', flexShrink: 0,
          }}
          onMouseEnter={e => e.currentTarget.style.color = 'var(--text-primary)'}
          onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
          <Clock size={14} />
        </button>
      </div>

      {open && ReactDOM.createPortal(
        <div ref={dropRef} style={{
          position: 'fixed',
          top: (() => { const r = ref.current?.getBoundingClientRect(); return r ? r.bottom + 4 : 0 })(),
          left: (() => { const r = ref.current?.getBoundingClientRect(); return r ? r.left : 0 })(),
          zIndex: 99999,
          background: 'var(--bg-card)', border: '1px solid var(--border-primary)',
          borderRadius: 12, boxShadow: '0 8px 32px rgba(0,0,0,0.12)',
          padding: 12, display: 'flex', alignItems: 'center', gap: 6,
          animation: 'selectIn 0.15s ease-out',
          backdropFilter: 'blur(24px)', WebkitBackdropFilter: 'blur(24px)',
        }}>
          {/* Hours */}
          <div style={{ display: 'flex', flexDirection: 'column', alignItems: 'center', gap: 2 }}>
            <button type="button" onClick={incHour} style={btnStyle}
              onMouseEnter={e => e.currentTarget.style.color = 'var(--text-primary)'}
              onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
              <ChevronUp size={16} />
            </button>
            <div style={{
              width: 44, height: 40, display: 'flex', alignItems: 'center', justifyContent: 'center',
              fontSize: 22, fontWeight: 700, color: 'var(--text-primary)',
              background: 'var(--bg-hover)', borderRadius: 8,
              fontVariantNumeric: 'tabular-nums',
            }}>
              {hour !== null ? (is12h ? String(hour === 0 ? 12 : hour > 12 ? hour - 12 : hour) : String(hour).padStart(2, '0')) : '--'}
            </div>
            <button type="button" onClick={decHour} style={btnStyle}
              onMouseEnter={e => e.currentTarget.style.color = 'var(--text-primary)'}
              onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
              <ChevronDown size={16} />
            </button>
          </div>

          <span style={{ fontSize: 22, fontWeight: 700, color: 'var(--text-faint)', marginTop: -2 }}>:</span>

          {/* Minutes */}
          <div style={{ display: 'flex', flexDirection: 'column', alignItems: 'center', gap: 2 }}>
            <button type="button" onClick={incMin} style={btnStyle}
              onMouseEnter={e => e.currentTarget.style.color = 'var(--text-primary)'}
              onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
              <ChevronUp size={16} />
            </button>
            <div style={{
              width: 44, height: 40, display: 'flex', alignItems: 'center', justifyContent: 'center',
              fontSize: 22, fontWeight: 700, color: 'var(--text-primary)',
              background: 'var(--bg-hover)', borderRadius: 8,
              fontVariantNumeric: 'tabular-nums',
            }}>
              {minute !== null ? String(minute).padStart(2, '0') : '--'}
            </div>
            <button type="button" onClick={decMin} style={btnStyle}
              onMouseEnter={e => e.currentTarget.style.color = 'var(--text-primary)'}
              onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
              <ChevronDown size={16} />
            </button>
          </div>

          {/* AM/PM Toggle */}
          {is12h && hour !== null && (
            <div style={{ display: 'flex', flexDirection: 'column', alignItems: 'center', gap: 2, marginLeft: 4 }}>
              <button type="button" onClick={() => { if (hour < 12) update(hour + 12, minute ?? 0); else update(hour - 12, minute ?? 0) }} style={btnStyle}
                onMouseEnter={e => e.currentTarget.style.color = 'var(--text-primary)'}
                onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
                <ChevronUp size={16} />
              </button>
              <div style={{
                width: 36, height: 40, display: 'flex', alignItems: 'center', justifyContent: 'center',
                fontSize: 14, fontWeight: 700, color: 'var(--text-primary)',
                background: 'var(--bg-hover)', borderRadius: 8,
              }}>
                {hour >= 12 ? 'PM' : 'AM'}
              </div>
              <button type="button" onClick={() => { if (hour < 12) update(hour + 12, minute ?? 0); else update(hour - 12, minute ?? 0) }} style={btnStyle}
                onMouseEnter={e => e.currentTarget.style.color = 'var(--text-primary)'}
                onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
                <ChevronDown size={16} />
              </button>
            </div>
          )}

          {/* Clear */}
          {value && (
            <button type="button" onClick={() => { onChange(''); setOpen(false) }}
              style={{ ...btnStyle, marginLeft: 4, fontSize: 11, color: 'var(--text-faint)', padding: '4px 6px' }}
              onMouseEnter={e => e.currentTarget.style.color = '#ef4444'}
              onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
              ✕
            </button>
          )}
        </div>,
        document.body
      )}

      <style>{`@keyframes selectIn { from { opacity: 0; transform: translateY(-4px); } to { opacity: 1; transform: translateY(0); } }`}</style>
    </div>
  )
}