'use client'

import { useCallback, useEffect, useState } from 'react'
import type { WorkspaceComponentProps } from '@/lib/extensions/workspace-registry'
import type { InvoiceInboxItem, Supplier, InboxItemStatus } from '@/types'
import type { InvoiceInboxSettings } from '@/extensions/general/invoice-inbox/types'
import { PageHeader } from '@/components/ui/page-header'
import { Card, CardContent } from '@/components/ui/card'
import { Tabs, TabsList, TabsTrigger, TabsContent } from '@/components/ui/tabs'
import { Button } from '@/components/ui/button'
import { Skeleton } from '@/components/ui/skeleton'
import { Settings, Inbox, CheckCircle2, AlertTriangle } from 'lucide-react'
import InboxItemCard from '@/components/extensions/general/invoice-inbox/InboxItemCard'
import InboxUploadZone from '@/components/extensions/general/invoice-inbox/InboxUploadZone'
import InboxDetailDialog from '@/components/extensions/general/invoice-inbox/InboxDetailDialog'
import InboxSettingsDialog from '@/components/extensions/general/invoice-inbox/InboxSettingsDialog'

type TabValue = 'all' | InboxItemStatus

const TABS: { value: TabValue; label: string }[] = [
  { value: 'all', label: 'Alla' },
  { value: 'pending', label: 'Ny' },
  { value: 'ready', label: 'Klar' },
  { value: 'confirmed', label: 'Bekräftad' },
  { value: 'rejected', label: 'Avvisad' },
  { value: 'error', label: 'Fel' },
]

const DEFAULT_SETTINGS: InvoiceInboxSettings = {
  autoProcessEnabled: true,
  autoMatchSupplierEnabled: true,
  supplierMatchThreshold: 0.7,
  inboxEmail: null,
}

export default function InvoiceInboxWorkspace({ userId }: WorkspaceComponentProps) {
  const [items, setItems] = useState<InvoiceInboxItem[]>([])
  const [loading, setLoading] = useState(true)
  const [activeTab, setActiveTab] = useState<TabValue>('all')
  const [selectedItem, setSelectedItem] = useState<InvoiceInboxItem | null>(null)
  const [isUploading, setIsUploading] = useState(false)
  const [settings, setSettings] = useState<InvoiceInboxSettings>(DEFAULT_SETTINGS)
  const [settingsOpen, setSettingsOpen] = useState(false)
  const [suppliers, setSuppliers] = useState<Supplier[]>([])

  const fetchItems = useCallback(async () => {
    try {
      const res = await fetch('/api/extensions/ext/invoice-inbox/inbox')
      if (res.ok) {
        const { data } = await res.json()
        setItems(data ?? [])
      }
    } catch {
      // Silently fail — user sees empty state
    } finally {
      setLoading(false)
    }
  }, [])

  const fetchSettings = useCallback(async () => {
    try {
      const res = await fetch('/api/extensions/ext/invoice-inbox/settings')
      if (res.ok) {
        const { data } = await res.json()
        if (data) setSettings(data)
      }
    } catch {
      // Use defaults
    }
  }, [])

  const fetchSuppliers = useCallback(async () => {
    try {
      const res = await fetch('/api/suppliers')
      if (res.ok) {
        const { data } = await res.json()
        setSuppliers(data ?? [])
      }
    } catch {
      // ok
    }
  }, [])

  useEffect(() => {
    fetchItems()
    fetchSettings()
    fetchSuppliers()
  }, [fetchItems, fetchSettings, fetchSuppliers])

  function handleUploadComplete(result: InvoiceInboxItem | InvoiceInboxItem[]) {
    const newItems = Array.isArray(result) ? result : [result]
    setItems((prev) => [...newItems, ...prev])
    for (const item of newItems) {
      pollItem(item.id)
    }
  }

  async function pollItem(itemId: string) {
    for (let i = 0; i < 20; i++) {
      await new Promise((r) => setTimeout(r, 3000))
      try {
        const res = await fetch(`/api/extensions/ext/invoice-inbox/inbox/${itemId}`)
        if (!res.ok) continue
        const { data } = await res.json()
        if (data && data.status !== 'processing') {
          setItems((prev) =>
            prev.map((it) => (it.id === itemId ? data : it))
          )
          // Also update the detail dialog if it's open for this item
          setSelectedItem((current) =>
            current?.id === itemId ? data : current
          )
          return
        }
      } catch {
        // continue polling
      }
    }
  }

  async function handleConfirm(
    itemId: string,
    supplierId?: string,
    newSupplierData?: import('@/components/extensions/general/invoice-inbox/InboxDetailDialog').NewSupplierData
  ) {
    const body: Record<string, unknown> = {}
    if (supplierId) {
      body.supplier_id = supplierId
    } else if (newSupplierData) {
      body.new_supplier = newSupplierData
    }

    const res = await fetch(`/api/extensions/ext/invoice-inbox/inbox/${itemId}/confirm`, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify(body),
    })

    if (res.ok) {
      setItems((prev) =>
        prev.map((it) => (it.id === itemId ? { ...it, status: 'confirmed' as const } : it))
      )
      setSelectedItem(null)
      fetchSuppliers() // New supplier may have been created
    }
  }

  async function handleReject(itemId: string) {
    const res = await fetch(`/api/extensions/ext/invoice-inbox/inbox/${itemId}`, {
      method: 'DELETE',
    })

    if (res.ok) {
      setItems((prev) =>
        prev.map((it) => (it.id === itemId ? { ...it, status: 'rejected' as const } : it))
      )
      setSelectedItem(null)
    }
  }

  async function handleReprocess(itemId: string) {
    setItems((prev) =>
      prev.map((it) => (it.id === itemId ? { ...it, status: 'processing' as const } : it))
    )
    setSelectedItem(null)

    const res = await fetch(`/api/extensions/ext/invoice-inbox/inbox/${itemId}/process`, {
      method: 'POST',
    })

    if (res.ok) {
      const { data } = await res.json()
      if (data) {
        setItems((prev) => prev.map((it) => (it.id === itemId ? data : it)))
      }
    } else {
      // Refetch in case of error update
      fetchItems()
    }
  }

  async function handleSaveSettings(updated: InvoiceInboxSettings) {
    const res = await fetch('/api/extensions/ext/invoice-inbox/settings', {
      method: 'PUT',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify(updated),
    })

    if (res.ok) {
      const { data } = await res.json()
      if (data) setSettings(data)
    }
  }

  const filteredItems =
    activeTab === 'all'
      ? items
      : items.filter((it) => it.status === activeTab)

  const totalCount = items.length
  const readyCount = items.filter((it) => it.status === 'ready').length
  const errorCount = items.filter((it) => it.status === 'error').length

  return (
    <div className="space-y-6">
      <PageHeader
        title="Fakturainkorgen"
        description="Ladda upp leverantörsfakturor och låt AI extrahera data automatiskt"
        action={
          <Button
            variant="outline"
            size="icon"
            onClick={() => setSettingsOpen(true)}
          >
            <Settings className="h-4 w-4" />
          </Button>
        }
      />

      {/* KPI cards */}
      <div className="grid grid-cols-1 sm:grid-cols-3 gap-4">
        <Card>
          <CardContent className="flex items-center gap-3 p-4">
            <div className="flex h-10 w-10 items-center justify-center rounded-lg bg-primary/10">
              <Inbox className="h-5 w-5 text-primary" />
            </div>
            <div>
              <p className="text-2xl font-medium">{totalCount}</p>
              <p className="text-xs text-muted-foreground">Totalt</p>
            </div>
          </CardContent>
        </Card>
        <Card>
          <CardContent className="flex items-center gap-3 p-4">
            <div className="flex h-10 w-10 items-center justify-center rounded-lg bg-warning/15">
              <CheckCircle2 className="h-5 w-5 text-warning-foreground" />
            </div>
            <div>
              <p className="text-2xl font-medium">{readyCount}</p>
              <p className="text-xs text-muted-foreground">Att granska</p>
            </div>
          </CardContent>
        </Card>
        <Card>
          <CardContent className="flex items-center gap-3 p-4">
            <div className="flex h-10 w-10 items-center justify-center rounded-lg bg-destructive/10">
              <AlertTriangle className="h-5 w-5 text-destructive" />
            </div>
            <div>
              <p className="text-2xl font-medium">{errorCount}</p>
              <p className="text-xs text-muted-foreground">Fel</p>
            </div>
          </CardContent>
        </Card>
      </div>

      {/* Upload zone */}
      <InboxUploadZone
        onUploadComplete={handleUploadComplete}
        isUploading={isUploading}
        setIsUploading={setIsUploading}
      />

      {/* Tabs + item list */}
      <Tabs value={activeTab} onValueChange={(v) => setActiveTab(v as TabValue)}>
        <TabsList>
          {TABS.map((tab) => (
            <TabsTrigger key={tab.value} value={tab.value}>
              {tab.label}
            </TabsTrigger>
          ))}
        </TabsList>

        {TABS.map((tab) => (
          <TabsContent key={tab.value} value={tab.value}>
            {loading ? (
              <div className="space-y-3">
                {Array.from({ length: 3 }).map((_, i) => (
                  <Skeleton key={i} className="h-20 w-full rounded-xl" />
                ))}
              </div>
            ) : filteredItems.length === 0 ? (
              <div className="flex flex-col items-center justify-center py-12 text-center">
                <Inbox className="h-10 w-10 text-muted-foreground/40 mb-3" />
                <p className="text-sm text-muted-foreground">
                  {activeTab === 'all'
                    ? 'Inga fakturor ännu. Ladda upp en faktura ovan.'
                    : 'Inga fakturor med denna status.'}
                </p>
              </div>
            ) : (
              <div className="space-y-2">
                {filteredItems.map((item) => (
                  <InboxItemCard
                    key={item.id}
                    item={item}
                    onClick={() => setSelectedItem(item)}
                  />
                ))}
              </div>
            )}
          </TabsContent>
        ))}
      </Tabs>

      {/* Detail dialog */}
      <InboxDetailDialog
        item={selectedItem}
        open={selectedItem != null}
        onOpenChange={(open) => {
          if (!open) setSelectedItem(null)
        }}
        onConfirm={handleConfirm}
        onReject={handleReject}
        onReprocess={handleReprocess}
        suppliers={suppliers}
      />

      {/* Settings dialog */}
      <InboxSettingsDialog
        open={settingsOpen}
        onOpenChange={setSettingsOpen}
        settings={settings}
        onSave={handleSaveSettings}
      />
    </div>
  )
}