import { createClient } from "@/lib/supabase/client"

export type AIConversation = {
  id: string
  knowledge_item_id: string | null
  title: string | null
  created_at: string
  updated_at: string
}

export type AIMessageRow = {
  id: string
  conversation_id: string
  role: "user" | "assistant" | "system"
  content: string
  created_at: string
}

/** Get the latest conversation for a knowledge item, if any. */
export async function getLatestConversation(knowledgeItemId: string): Promise<AIConversation | null> {
  const supabase = createClient()
  const { data, error } = await supabase
    .from("ai_conversations")
    .select("*")
    .eq("knowledge_item_id", knowledgeItemId)
    .order("updated_at", { ascending: false })
    .limit(1)
    .maybeSingle()
  if (error) throw error
  return (data as AIConversation) ?? null
}

export async function createConversation(knowledgeItemId: string, title: string): Promise<AIConversation> {
  const supabase = createClient()
  const { data, error } = await supabase
    .from("ai_conversations")
    .insert({ knowledge_item_id: knowledgeItemId, title })
    .select("*")
    .single()
  if (error) throw error
  return data as AIConversation
}

export async function fetchMessages(conversationId: string): Promise<AIMessageRow[]> {
  const supabase = createClient()
  const { data, error } = await supabase
    .from("ai_messages")
    .select("*")
    .eq("conversation_id", conversationId)
    .order("created_at", { ascending: true })
  if (error) throw error
  return (data ?? []) as AIMessageRow[]
}

export async function addMessage(
  conversationId: string,
  role: "user" | "assistant",
  content: string,
): Promise<AIMessageRow> {
  const supabase = createClient()
  const { data, error } = await supabase
    .from("ai_messages")
    .insert({ conversation_id: conversationId, role, content })
    .select("*")
    .single()
  if (error) throw error
  // touch conversation updated_at
  await supabase.from("ai_conversations").update({ updated_at: new Date().toISOString() }).eq("id", conversationId)
  return data as AIMessageRow
}

export async function clearMessages(conversationId: string): Promise<void> {
  const supabase = createClient()
  const { error } = await supabase.from("ai_messages").delete().eq("conversation_id", conversationId)
  if (error) throw error
}

export async function deleteLastAssistantMessage(conversationId: string): Promise<void> {
  const supabase = createClient()
  const { data, error } = await supabase
    .from("ai_messages")
    .select("id, role")
    .eq("conversation_id", conversationId)
    .order("created_at", { ascending: false })
    .limit(1)
    .maybeSingle()
  if (error) throw error
  if (data && (data as { role: string }).role === "assistant") {
    await supabase.from("ai_messages").delete().eq("id", (data as { id: string }).id)
  }
}