import type { Database } from '~/types/database.types'

type InventoryItem = Database['public']['Tables']['inventory_items']['Row']
type InventoryItemInsert = Database['public']['Tables']['inventory_items']['Insert']
type InventoryItemUpdate = Database['public']['Tables']['inventory_items']['Update']

export const useInventory = () => {
  const supabase = useSupabase()
  const { user } = useSupabaseAuth()

  /**
   * Get all inventory items with denormalized data
   */
  const getInventory = async () => {
    const { data, error } = await supabase
      .from('inventory_items')
      .select(`
        *,
        product:products(*),
        unit:units(*),
        tags:item_tags(tag:tags(*))
      `)
      .order('created_at', { ascending: false })

    if (error) {
      console.error('Error fetching inventory:', error)
      return { data: null, error }
    }

    return { data, error: null }
  }

  /**
   * Get single inventory item by ID
   */
  const getInventoryItem = async (id: string) => {
    const { data, error } = await supabase
      .from('inventory_items')
      .select(`
        *,
        product:products(*),
        unit:units(*),
        tags:item_tags(tag:tags(*))
      `)
      .eq('id', id)
      .single()

    if (error) {
      console.error('Error fetching item:', error)
      return { data: null, error }
    }

    return { data, error: null }
  }

  /**
   * Add new inventory item
   */
  const addInventoryItem = async (item: Omit<InventoryItemInsert, 'added_by'>) => {
    if (!user.value) {
      return { data: null, error: { message: 'User not authenticated' } }
    }

    const { data, error } = await supabase
      .from('inventory_items')
      .insert({
        ...item,
        added_by: user.value.id
      })
      .select(`
        *,
        product:products(*),
        unit:units(*),
        tags:item_tags(tag:tags(*))
      `)
      .single()

    if (error) {
      console.error('Error adding item:', error)
      return { data: null, error }
    }

    return { data, error: null }
  }

  /**
   * Update inventory item
   */
  const updateInventoryItem = async (id: string, updates: InventoryItemUpdate) => {
    const { data, error } = await supabase
      .from('inventory_items')
      .update(updates)
      .eq('id', id)
      .select(`
        *,
        product:products(*),
        unit:units(*),
        tags:item_tags(tag:tags(*))
      `)
      .single()

    if (error) {
      console.error('Error updating item:', error)
      return { data: null, error }
    }

    return { data, error: null }
  }

  /**
   * Delete inventory item
   */
  const deleteInventoryItem = async (id: string) => {
    // First delete associated tags
    await supabase
      .from('item_tags')
      .delete()
      .eq('item_id', id)

    const { error } = await supabase
      .from('inventory_items')
      .delete()
      .eq('id', id)

    if (error) {
      console.error('Error deleting item:', error)
      return { error }
    }

    return { error: null }
  }

  /**
   * Update item quantity (consume or restock)
   */
  const updateQuantity = async (id: string, change: number) => {
    const { data: item, error: fetchError } = await getInventoryItem(id)
    if (fetchError || !item) {
      return { data: null, error: fetchError }
    }

    const newQuantity = Number(item.quantity) + change

    if (newQuantity <= 0) {
      // Auto-delete when quantity reaches zero
      return await deleteInventoryItem(id)
    }

    return await updateInventoryItem(id, { quantity: newQuantity })
  }

  /**
   * Add tags to item
   */
  const addItemTags = async (itemId: string, tagIds: string[]) => {
    const items = tagIds.map(tagId => ({
      item_id: itemId,
      tag_id: tagId
    }))

    const { error } = await supabase
      .from('item_tags')
      .insert(items)

    if (error) {
      console.error('Error adding tags:', error)
      return { error }
    }

    return { error: null }
  }

  /**
   * Remove tag from item
   */
  const removeItemTag = async (itemId: string, tagId: string) => {
    const { error } = await supabase
      .from('item_tags')
      .delete()
      .eq('item_id', itemId)
      .eq('tag_id', tagId)

    if (error) {
      console.error('Error removing tag:', error)
      return { error }
    }

    return { error: null }
  }

  return {
    getInventory,
    getInventoryItem,
    addInventoryItem,
    updateInventoryItem,
    deleteInventoryItem,
    updateQuantity,
    addItemTags,
    removeItemTag
  }
}