'use client'

import { useEffect, useState } from 'react'
import { useParams } from 'next/navigation'
import { motion } from 'framer-motion'
import { getDateRange, formatDate } from '@ciphera-net/ui'
import { Select, DatePicker } from '@ciphera-net/ui'
import ColumnJourney from '@/components/journeys/ColumnJourney'
import SankeyJourney from '@/components/journeys/SankeyJourney'
import TopPathsTable from '@/components/journeys/TopPathsTable'
import { JourneysSkeleton, useMinimumLoading, useSkeletonFade } from '@/components/skeletons'
import {
  useDashboard,
  useJourneyTransitions,
  useJourneyTopPaths,
  useJourneyEntryPoints,
} from '@/lib/swr/dashboard'

const DEFAULT_DEPTH = 4

function getThisWeekRange(): { start: string; end: string } {
  const today = new Date()
  const dayOfWeek = today.getDay()
  const monday = new Date(today)
  monday.setDate(today.getDate() - (dayOfWeek === 0 ? 6 : dayOfWeek - 1))
  return { start: formatDate(monday), end: formatDate(today) }
}

function getThisMonthRange(): { start: string; end: string } {
  const today = new Date()
  const firstOfMonth = new Date(today.getFullYear(), today.getMonth(), 1)
  return { start: formatDate(firstOfMonth), end: formatDate(today) }
}

export default function JourneysPage() {
  const params = useParams()
  const siteId = params.id as string

  const [period, setPeriod] = useState('30')
  const [dateRange, setDateRange] = useState(() => getDateRange(30))
  const [isDatePickerOpen, setIsDatePickerOpen] = useState(false)
  const [depth, setDepth] = useState(DEFAULT_DEPTH)
  const [committedDepth, setCommittedDepth] = useState(DEFAULT_DEPTH)
  const [entryPath, setEntryPath] = useState('')
  const [viewMode, setViewMode] = useState<'columns' | 'flow'>('columns')

  useEffect(() => {
    const t = setTimeout(() => setCommittedDepth(depth), 300)
    return () => clearTimeout(t)
  }, [depth])

  const isDefault = depth === DEFAULT_DEPTH && !entryPath

  function resetFilters() {
    setDepth(DEFAULT_DEPTH)
    setCommittedDepth(DEFAULT_DEPTH)
    setEntryPath('')
  }

  const { data: transitionsData, isLoading: transitionsLoading } = useJourneyTransitions(
    siteId, dateRange.start, dateRange.end, committedDepth, 1, entryPath || undefined
  )
  const { data: topPaths, isLoading: topPathsLoading } = useJourneyTopPaths(
    siteId, dateRange.start, dateRange.end, 20, 1, entryPath || undefined
  )
  const { data: entryPoints } = useJourneyEntryPoints(siteId, dateRange.start, dateRange.end)
  const { data: dashboard } = useDashboard(siteId, dateRange.start, dateRange.end)

  useEffect(() => {
    const domain = dashboard?.site?.domain
    document.title = domain ? `Journeys \u00b7 ${domain} | Pulse` : 'Journeys | Pulse'
  }, [dashboard?.site?.domain])

  const showSkeleton = useMinimumLoading(transitionsLoading && !transitionsData)
  const fadeClass = useSkeletonFade(showSkeleton)

  const entryPointOptions = [
    { value: '', label: 'All entry points' },
    ...(entryPoints ?? []).map((ep) => ({
      value: ep.path,
      label: `${ep.path} (${ep.session_count.toLocaleString()})`,
    })),
  ]

  if (showSkeleton) return <JourneysSkeleton />

  const totalSessions = transitionsData?.total_sessions ?? 0

  return (
    <div className={`w-full max-w-6xl mx-auto px-4 sm:px-6 pb-8 ${fadeClass}`}>
      {/* Header */}
      <div className="mb-8 flex flex-col sm:flex-row sm:items-center sm:justify-between gap-4">
        <div>
          <h1 className="text-2xl font-bold text-neutral-900 dark:text-white mb-1">
            Journeys
          </h1>
          <p className="text-sm text-neutral-500 dark:text-neutral-400">
            How visitors navigate through your site
          </p>
        </div>
        <Select
          variant="input"
          className="min-w-[140px]"
          value={period}
          onChange={(value) => {
            if (value === 'today') {
              const today = formatDate(new Date())
              setDateRange({ start: today, end: today })
              setPeriod('today')
            } else if (value === '7') {
              setDateRange(getDateRange(7))
              setPeriod('7')
            } else if (value === 'week') {
              setDateRange(getThisWeekRange())
              setPeriod('week')
            } else if (value === '30') {
              setDateRange(getDateRange(30))
              setPeriod('30')
            } else if (value === 'month') {
              setDateRange(getThisMonthRange())
              setPeriod('month')
            } else if (value === 'custom') {
              setIsDatePickerOpen(true)
            }
          }}
          options={[
            { value: 'today', label: 'Today' },
            { value: '7', label: 'Last 7 days' },
            { value: '30', label: 'Last 30 days' },
            { value: 'divider-1', label: '', divider: true },
            { value: 'week', label: 'This week' },
            { value: 'month', label: 'This month' },
            { value: 'divider-2', label: '', divider: true },
            { value: 'custom', label: 'Custom' },
          ]}
        />
      </div>

      {/* Single card: toolbar + chart */}
      <div className="bg-white dark:bg-neutral-900 border border-neutral-200 dark:border-neutral-800 rounded-2xl overflow-hidden">
        {/* Toolbar */}
        <div className="p-6 border-b border-neutral-200 dark:border-neutral-800 bg-neutral-50/50 dark:bg-neutral-900/50">
          <div className="flex flex-col sm:flex-row sm:items-center gap-6">
            {/* Depth slider */}
            <div className="flex-1">
              <div className="flex justify-between text-sm font-medium text-neutral-500 dark:text-neutral-400 mb-3">
                <span>2 steps</span>
                <span className="text-brand-orange font-bold">
                  {depth} steps deep
                </span>
                <span>6 steps</span>
              </div>
              <input
                type="range"
                min={2}
                max={6}
                step={1}
                value={depth}
                onChange={(e) => setDepth(parseInt(e.target.value))}
                aria-label="Journey depth"
                aria-valuetext={`${depth} steps deep`}
                className="w-full h-2 bg-neutral-200 rounded-lg appearance-none cursor-pointer dark:bg-neutral-700 accent-brand-orange focus:outline-none"
              />
            </div>

            {/* Entry point + Reset */}
            <div className="flex items-center gap-3 shrink-0">
              <Select
                variant="input"
                className="min-w-[180px]"
                value={entryPath}
                onChange={(value) => setEntryPath(value)}
                options={entryPointOptions}
              />
              <button
                onClick={resetFilters}
                disabled={isDefault}
                className={`text-sm whitespace-nowrap transition-all duration-150 ${
                  isDefault
                    ? 'opacity-0 pointer-events-none'
                    : 'opacity-100 text-neutral-500 hover:text-neutral-900 dark:hover:text-white'
                }`}
              >
                Reset
              </button>
            </div>
          </div>

          {/* View toggle */}
          <div className="flex gap-1 mt-4 pt-4 border-t border-neutral-200 dark:border-neutral-800" role="tablist" aria-label="Journey view tabs">
            {(['columns', 'flow'] as const).map((mode) => (
              <button
                key={mode}
                onClick={() => setViewMode(mode)}
                role="tab"
                aria-selected={viewMode === mode}
                className={`relative px-3 py-1 text-xs font-medium transition-colors capitalize focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-brand-orange rounded cursor-pointer ${
                  viewMode === mode
                    ? 'text-neutral-900 dark:text-white'
                    : 'text-neutral-400 dark:text-neutral-500 hover:text-neutral-700 dark:hover:text-neutral-300'
                }`}
              >
                {mode === 'columns' ? 'Columns' : 'Flow'}
                {viewMode === mode && (
                  <motion.div
                    layoutId="journeyViewTab"
                    className="absolute inset-x-0 -bottom-px h-0.5 bg-brand-orange"
                    transition={{ type: 'spring', stiffness: 500, damping: 35 }}
                  />
                )}
              </button>
            ))}
          </div>
        </div>

        {/* Journey Chart */}
        <div className="p-6">
          {viewMode === 'columns' ? (
            <ColumnJourney
              transitions={transitionsData?.transitions ?? []}
              totalSessions={totalSessions}
              depth={committedDepth}
            />
          ) : (
            <SankeyJourney
              transitions={transitionsData?.transitions ?? []}
              totalSessions={totalSessions}
              depth={committedDepth}
            />
          )}
        </div>

        {/* Footer */}
        {totalSessions > 0 && (
          <div className="px-6 pb-5 text-sm text-neutral-500 dark:text-neutral-400">
            {totalSessions.toLocaleString()} sessions tracked
          </div>
        )}
      </div>

      {/* Top Paths */}
      <div className="mt-6">
        <TopPathsTable paths={topPaths ?? []} loading={topPathsLoading} />
      </div>

      {/* Date Picker Modal */}
      <DatePicker
        isOpen={isDatePickerOpen}
        onClose={() => setIsDatePickerOpen(false)}
        onApply={(range) => {
          setDateRange(range)
          setPeriod('custom')
          setIsDatePickerOpen(false)
        }}
        initialRange={dateRange}
      />
    </div>
  )
}
