import { useState, useEffect, useContext } from 'react'
import { useNavigate } from 'react-router-dom'
import { Plus, Search, TrendingUp, DollarSign, Eye, MousePointer, Target, BarChart3 } from 'lucide-react'
import { format } from 'date-fns'
import { AppContext } from '../App'
import { useAuth } from '../contexts/AuthContext'
import { useLanguage } from '../i18n/LanguageContext'
import { api, PLATFORMS } from '../utils/api'
import { PlatformIcons } from '../components/PlatformIcon'
import StatusBadge from '../components/StatusBadge'
import BrandBadge from '../components/BrandBadge'
import BudgetBar from '../components/BudgetBar'
import InteractiveTimeline from '../components/InteractiveTimeline'
import CampaignDetailPanel from '../components/CampaignDetailPanel'
import Modal from '../components/Modal'
import { SkeletonStatCard, SkeletonTable } from '../components/SkeletonLoader'

const EMPTY_CAMPAIGN = {
  name: '', description: '', brand_id: '', status: 'planning',
  start_date: '', end_date: '', budget: '', team_id: '',
}

function ROIBadge({ revenue, spent }) {
  if (!spent || spent <= 0) return null
  const roi = ((revenue - spent) / spent * 100).toFixed(0)
  const color = roi >= 0 ? 'text-emerald-600 bg-emerald-50' : 'text-red-600 bg-red-50'
  return (
    <span className={`text-[10px] font-semibold px-1.5 py-0.5 rounded ${color}`}>
      ROI {roi}%
    </span>
  )
}

function MetricCard({ icon: Icon, label, value, color = 'text-text-primary' }) {
  return (
    <div className="bg-surface-secondary rounded-lg p-3 text-center">
      <Icon className={`w-4 h-4 mx-auto mb-1 ${color}`} />
      <div className={`text-sm font-bold ${color}`}>{value || '—'}</div>
      <div className="text-[10px] text-text-tertiary">{label}</div>
    </div>
  )
}

export default function Campaigns() {
  const { brands, getBrandName, teams } = useContext(AppContext)
  const { t, lang, currencySymbol } = useLanguage()
  const { permissions } = useAuth()
  const navigate = useNavigate()
  const [campaigns, setCampaigns] = useState([])
  const [loading, setLoading] = useState(true)
  const [panelCampaign, setPanelCampaign] = useState(null)
  const [filters, setFilters] = useState({ brand: '', status: '' })
  const [showCreateModal, setShowCreateModal] = useState(false)
  const [createForm, setCreateForm] = useState({ ...EMPTY_CAMPAIGN })
  const [createSaving, setCreateSaving] = useState(false)

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

  const loadCampaigns = async () => {
    try {
      const res = await api.get('/campaigns')
      setCampaigns(Array.isArray(res) ? res : [])
    } catch (err) {
      console.error('Failed to load campaigns:', err)
    } finally {
      setLoading(false)
    }
  }

  const handlePanelSave = async (campaignId, data) => {
    if (campaignId) {
      await api.patch(`/campaigns/${campaignId}`, data)
    } else {
      await api.post('/campaigns', data)
    }
    loadCampaigns()
  }

  const handlePanelDelete = async (campaignId) => {
    await api.delete(`/campaigns/${campaignId}`)
    loadCampaigns()
  }

  const openNew = () => {
    setCreateForm({ ...EMPTY_CAMPAIGN })
    setShowCreateModal(true)
  }

  const handleCreate = async () => {
    setCreateSaving(true)
    try {
      const data = {
        name: createForm.name,
        description: createForm.description,
        brand_id: createForm.brand_id ? Number(createForm.brand_id) : null,
        status: createForm.status,
        start_date: createForm.start_date || null,
        end_date: createForm.end_date || null,
        budget: createForm.budget ? Number(createForm.budget) : null,
        team_id: createForm.team_id ? Number(createForm.team_id) : null,
      }
      const created = await api.post('/campaigns', data)
      setShowCreateModal(false)
      loadCampaigns()
      // Navigate to the new campaign detail page
      const id = created?.Id || created?.id || created?._id
      if (id) navigate(`/campaigns/${id}`)
    } catch (err) {
      console.error('Create campaign failed:', err)
    } finally {
      setCreateSaving(false)
    }
  }

  const filtered = campaigns.filter(c => {
    if (filters.brand && String(c.brandId || c.brand_id) !== filters.brand) return false
    if (filters.status && c.status !== filters.status) return false
    return true
  })

  // Aggregate stats
  const totalBudget = filtered.reduce((sum, c) => sum + (c.budget || 0), 0)
  const totalSpent = filtered.reduce((sum, c) => sum + (c.budgetSpent || c.budget_spent || 0), 0)
  const totalImpressions = filtered.reduce((sum, c) => sum + (c.impressions || 0), 0)
  const totalClicks = filtered.reduce((sum, c) => sum + (c.clicks || 0), 0)
  const totalConversions = filtered.reduce((sum, c) => sum + (c.conversions || 0), 0)
  const totalRevenue = filtered.reduce((sum, c) => sum + (c.revenue || 0), 0)

  if (loading) {
    return (
      <div className="space-y-6">
        <div className="h-12 bg-surface-tertiary rounded-xl animate-pulse"></div>
        <div className="grid grid-cols-2 md:grid-cols-3 lg:grid-cols-6 gap-3">
          {[...Array(6)].map((_, i) => <SkeletonStatCard key={i} />)}
        </div>
        <SkeletonTable rows={5} cols={6} />
      </div>
    )
  }

  return (
    <div className="space-y-6 animate-fade-in">
      {/* Toolbar */}
      <div className="flex flex-wrap items-center gap-3">
        <select
          value={filters.brand}
          onChange={e => setFilters(f => ({ ...f, brand: e.target.value }))}
          className="text-sm border border-border rounded-lg px-3 py-2 bg-surface text-text-secondary focus:outline-none"
        >
          <option value="">All Brands</option>
          {brands.map(b => <option key={b.id || b._id} value={b.id || b._id}>{lang === 'ar' && b.name_ar ? b.name_ar : b.name}</option>)}
        </select>

        <select
          value={filters.status}
          onChange={e => setFilters(f => ({ ...f, status: e.target.value }))}
          className="text-sm border border-border rounded-lg px-3 py-2 bg-surface text-text-secondary focus:outline-none"
        >
          <option value="">All Statuses</option>
          <option value="planning">Planning</option>
          <option value="active">Active</option>
          <option value="paused">Paused</option>
          <option value="completed">Completed</option>
          <option value="cancelled">Cancelled</option>
        </select>

        {permissions?.canCreateCampaigns && (
          <button
            onClick={openNew}
            className="flex items-center gap-2 px-4 py-2 bg-brand-primary text-white rounded-lg text-sm font-medium hover:bg-brand-primary-light shadow-sm ms-auto"
          >
            <Plus className="w-4 h-4" />
            New Campaign
          </button>
        )}
      </div>

      {/* Summary Cards */}
      {(totalBudget > 0 || totalSpent > 0) && (
        <div className="grid grid-cols-2 md:grid-cols-3 lg:grid-cols-6 gap-3 stagger-children">
          <div className="bg-surface rounded-xl border border-border p-4">
            <div className="flex items-center gap-2 mb-1">
              <DollarSign className="w-4 h-4 text-blue-500" />
              <span className="text-[10px] uppercase tracking-wider text-text-tertiary font-medium">Budget</span>
            </div>
            <div className="text-lg font-bold text-text-primary">{totalBudget.toLocaleString()}</div>
            <div className="text-[10px] text-text-tertiary">{currencySymbol} total</div>
          </div>
          <div className="bg-surface rounded-xl border border-border p-4">
            <div className="flex items-center gap-2 mb-1">
              <TrendingUp className="w-4 h-4 text-amber-500" />
              <span className="text-[10px] uppercase tracking-wider text-text-tertiary font-medium">Spent</span>
            </div>
            <div className="text-lg font-bold text-text-primary">{totalSpent.toLocaleString()}</div>
            <div className="text-[10px] text-text-tertiary">{currencySymbol} spent</div>
          </div>
          <div className="bg-surface rounded-xl border border-border p-4">
            <div className="flex items-center gap-2 mb-1">
              <Eye className="w-4 h-4 text-purple-500" />
              <span className="text-[10px] uppercase tracking-wider text-text-tertiary font-medium">Impressions</span>
            </div>
            <div className="text-lg font-bold text-text-primary">{totalImpressions.toLocaleString()}</div>
          </div>
          <div className="bg-surface rounded-xl border border-border p-4">
            <div className="flex items-center gap-2 mb-1">
              <MousePointer className="w-4 h-4 text-green-500" />
              <span className="text-[10px] uppercase tracking-wider text-text-tertiary font-medium">Clicks</span>
            </div>
            <div className="text-lg font-bold text-text-primary">{totalClicks.toLocaleString()}</div>
          </div>
          <div className="bg-surface rounded-xl border border-border p-4">
            <div className="flex items-center gap-2 mb-1">
              <Target className="w-4 h-4 text-red-500" />
              <span className="text-[10px] uppercase tracking-wider text-text-tertiary font-medium">Conversions</span>
            </div>
            <div className="text-lg font-bold text-text-primary">{totalConversions.toLocaleString()}</div>
          </div>
          <div className="bg-surface rounded-xl border border-border p-4">
            <div className="flex items-center gap-2 mb-1">
              <BarChart3 className="w-4 h-4 text-emerald-500" />
              <span className="text-[10px] uppercase tracking-wider text-text-tertiary font-medium">Revenue</span>
            </div>
            <div className="text-lg font-bold text-text-primary">{totalRevenue.toLocaleString()}</div>
            <div className="text-[10px] text-text-tertiary">{currencySymbol}</div>
          </div>
        </div>
      )}

      {/* Timeline */}
      <InteractiveTimeline
        items={filtered}
        mapItem={(campaign) => ({
          id: campaign._id || campaign.id,
          label: campaign.name,
          description: campaign.description,
          startDate: campaign.startDate || campaign.start_date || campaign.createdAt,
          endDate: campaign.endDate || campaign.end_date,
          status: campaign.status,
          assigneeName: campaign.brandName || campaign.brand_name,
          tags: campaign.platforms || [],
          color: campaign.color,
        })}
        onDateChange={async (campaignId, { startDate, endDate }) => {
          try {
            await api.patch(`/campaigns/${campaignId}`, { start_date: startDate, end_date: endDate })
          } catch (err) {
            console.error('Timeline date update failed:', err)
          } finally {
            loadCampaigns()
          }
        }}
        onColorChange={async (campaignId, color) => {
          try {
            await api.patch(`/campaigns/${campaignId}`, { color: color || '' })
          } catch (err) {
            console.error('Color update failed:', err)
          } finally {
            loadCampaigns()
          }
        }}
        onItemClick={(campaign) => {
          navigate(`/campaigns/${campaign._id || campaign.id}`)
        }}
      />

      {/* Campaign list */}
      <div className="bg-surface rounded-xl border border-border overflow-clip">
        <div className="px-5 py-4 border-b border-border">
          <h3 className="font-semibold text-text-primary">All Campaigns</h3>
        </div>
        <div className="divide-y divide-border-light">
          {filtered.length === 0 ? (
            <div className="py-12 text-center text-sm text-text-tertiary">
              No campaigns found
            </div>
          ) : (
            filtered.map(campaign => {
              const spent = campaign.budgetSpent || campaign.budget_spent || 0
              const budget = campaign.budget || 0
              return (
                <div
                  key={campaign.id || campaign._id}
                  onClick={() => navigate(`/campaigns/${campaign.id || campaign._id}`)}
                  className="relative px-5 py-4 hover:bg-surface-secondary cursor-pointer transition-colors"
                >
                  <div className="flex items-center gap-4">
                    <div className="flex-1 min-w-0">
                      <div className="flex items-center gap-2 mb-1">
                        <h4 className="text-sm font-semibold text-text-primary">{campaign.name}</h4>
                        {(campaign.brand_id || campaign.brandName) && <BrandBadge brand={getBrandName(campaign.brand_id) || campaign.brandName} />}
                        <ROIBadge revenue={campaign.revenue || 0} spent={spent} />
                      </div>
                      {campaign.description && (
                        <p className="text-xs text-text-secondary line-clamp-1">{campaign.description}</p>
                      )}
                      <div className="flex items-center gap-3 mt-1.5">
                        {budget > 0 && (
                          <div className="w-32">
                            <BudgetBar budget={budget} spent={spent} />
                          </div>
                        )}
                        {(campaign.impressions > 0 || campaign.clicks > 0) && (
                          <div className="flex items-center gap-3 text-[10px] text-text-tertiary">
                            {campaign.impressions > 0 && <span>👁 {campaign.impressions.toLocaleString()}</span>}
                            {campaign.clicks > 0 && <span>🖱 {campaign.clicks.toLocaleString()}</span>}
                            {campaign.conversions > 0 && <span>🎯 {campaign.conversions.toLocaleString()}</span>}
                          </div>
                        )}
                      </div>
                    </div>
                    <div className="text-end shrink-0">
                      <StatusBadge status={campaign.status} size="xs" />
                      <div className="text-xs text-text-tertiary mt-1">
                        {campaign.startDate && campaign.endDate ? (
                          <>
                            {format(new Date(campaign.startDate), 'MMM d')} – {format(new Date(campaign.endDate), 'MMM d, yyyy')}
                          </>
                        ) : '—'}
                      </div>
                    </div>
                  </div>
                  {campaign.platforms && campaign.platforms.length > 0 && (
                    <div className="flex justify-end mt-2">
                      <PlatformIcons platforms={campaign.platforms} size={16} />
                    </div>
                  )}
                </div>
              )
            })
          )}
        </div>
      </div>

      {/* Create Campaign Modal */}
      <Modal isOpen={showCreateModal} onClose={() => setShowCreateModal(false)} title={t('campaigns.newCampaign') || 'New Campaign'} size="md">
        <div className="space-y-4">
          <div>
            <label className="block text-xs font-medium text-text-tertiary mb-1">{t('campaigns.name')} *</label>
            <input type="text" value={createForm.name} onChange={e => setCreateForm(f => ({ ...f, name: e.target.value }))}
              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary" autoFocus />
          </div>
          <div>
            <label className="block text-xs font-medium text-text-tertiary mb-1">{t('campaigns.description')}</label>
            <textarea value={createForm.description} onChange={e => setCreateForm(f => ({ ...f, description: e.target.value }))} rows={2}
              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary resize-none" />
          </div>
          <div className="grid grid-cols-2 gap-3">
            <div>
              <label className="block text-xs font-medium text-text-tertiary mb-1">{t('campaigns.brand')}</label>
              <select value={createForm.brand_id} onChange={e => setCreateForm(f => ({ ...f, brand_id: e.target.value }))}
                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary">
                <option value="">{t('posts.allBrands')}</option>
                {brands.map(b => <option key={b.id || b._id} value={b.id || b._id}>{lang === 'ar' && b.name_ar ? b.name_ar : b.name}</option>)}
              </select>
            </div>
            <div>
              <label className="block text-xs font-medium text-text-tertiary mb-1">{t('common.team')}</label>
              <select value={createForm.team_id} onChange={e => setCreateForm(f => ({ ...f, team_id: e.target.value }))}
                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary">
                <option value="">{t('common.noTeam')}</option>
                {(teams || []).map(team => <option key={team.id || team._id} value={team.id || team._id}>{team.name}</option>)}
              </select>
            </div>
          </div>
          <div className="grid grid-cols-2 gap-3">
            <div>
              <label className="block text-xs font-medium text-text-tertiary mb-1">{t('campaigns.startDate')}</label>
              <input type="date" value={createForm.start_date} onChange={e => setCreateForm(f => ({ ...f, start_date: e.target.value }))}
                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary" />
            </div>
            <div>
              <label className="block text-xs font-medium text-text-tertiary mb-1">{t('campaigns.endDate')}</label>
              <input type="date" value={createForm.end_date} onChange={e => setCreateForm(f => ({ ...f, end_date: e.target.value }))}
                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary" />
            </div>
          </div>
          <div>
            <label className="block text-xs font-medium text-text-tertiary mb-1">{t('campaigns.budget')}</label>
            <input type="number" value={createForm.budget} onChange={e => setCreateForm(f => ({ ...f, budget: e.target.value }))}
              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary" placeholder="0" />
          </div>
          <button onClick={handleCreate} disabled={!createForm.name || createSaving}
            className={`w-full px-4 py-2.5 bg-brand-primary text-white rounded-lg text-sm font-medium hover:bg-brand-primary-light disabled:opacity-50 disabled:cursor-not-allowed shadow-sm ${createSaving ? 'btn-loading' : ''}`}>
            {t('campaigns.newCampaign') || 'Create Campaign'}
          </button>
        </div>
      </Modal>

      {/* Campaign Panel (edit only) */}
      {panelCampaign && (
        <CampaignDetailPanel
          campaign={panelCampaign}
          onClose={() => setPanelCampaign(null)}
          onSave={handlePanelSave}
          onDelete={permissions?.canDeleteCampaigns ? handlePanelDelete : null}
          brands={brands}
          permissions={permissions}
        />
      )}
    </div>
  )
}