// Author: Simon-Pierre Boucher
// Contact: contact@spboucher.ai
// Project: chat.spboucher.ai

import crypto from "node:crypto";
import { getDb } from "@/lib/db/database";

export interface ConversationRow {
  id: string;
  title: string;
  pinned: number;
  current_leaf_id: string | null;
  created_at: number;
  updated_at: number;
}

export interface MessageRow {
  id: string;
  conversation_id: string;
  parent_id: string | null;
  role: "user" | "assistant" | "system";
  content: string;
  reasoning: string | null;
  model_id: string | null;
  model_name: string | null;
  provider: string | null;
  generation_id: string | null;
  status: "pending" | "streaming" | "completed" | "cancelled" | "failed";
  error_message: string | null;
  created_at: number;
}

export function listConversations(): ConversationRow[] {
  return getDb()
    .prepare("SELECT * FROM conversations ORDER BY pinned DESC, updated_at DESC")
    .all() as ConversationRow[];
}

export function getConversation(id: string): ConversationRow | null {
  return (getDb().prepare("SELECT * FROM conversations WHERE id = ?").get(id) as ConversationRow) ?? null;
}

export function createConversation(title?: string): ConversationRow {
  const db = getDb();
  const id = crypto.randomUUID();
  const now = Date.now();
  db.prepare(
    "INSERT INTO conversations (id, title, created_at, updated_at) VALUES (?, ?, ?, ?)"
  ).run(id, title?.slice(0, 80) || "New conversation", now, now);
  return getConversation(id)!;
}

export function updateConversation(
  id: string,
  patch: { title?: string; pinned?: boolean; currentLeafId?: string | null }
): void {
  const db = getDb();
  if (patch.title !== undefined) {
    db.prepare("UPDATE conversations SET title = ?, updated_at = ? WHERE id = ?").run(
      patch.title.slice(0, 120),
      Date.now(),
      id
    );
  }
  if (patch.pinned !== undefined) {
    db.prepare("UPDATE conversations SET pinned = ? WHERE id = ?").run(patch.pinned ? 1 : 0, id);
  }
  if (patch.currentLeafId !== undefined) {
    db.prepare("UPDATE conversations SET current_leaf_id = ? WHERE id = ?").run(patch.currentLeafId, id);
  }
}

export function deleteConversation(id: string): void {
  getDb().prepare("DELETE FROM conversations WHERE id = ?").run(id);
}

export function touchConversation(id: string): void {
  getDb().prepare("UPDATE conversations SET updated_at = ? WHERE id = ?").run(Date.now(), id);
}

export function listMessages(conversationId: string): MessageRow[] {
  return getDb()
    .prepare("SELECT * FROM messages WHERE conversation_id = ? ORDER BY created_at, id")
    .all(conversationId) as MessageRow[];
}

export function getMessage(id: string): MessageRow | null {
  return (getDb().prepare("SELECT * FROM messages WHERE id = ?").get(id) as MessageRow) ?? null;
}

export function insertMessage(m: {
  conversationId: string;
  parentId: string | null;
  role: "user" | "assistant" | "system";
  content?: string;
  modelId?: string;
  modelName?: string;
  provider?: string;
  generationId?: string;
  status?: MessageRow["status"];
}): MessageRow {
  const db = getDb();
  const id = crypto.randomUUID();
  db.prepare(
    `INSERT INTO messages (id, conversation_id, parent_id, role, content, model_id, model_name, provider, generation_id, status, created_at)
     VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`
  ).run(
    id,
    m.conversationId,
    m.parentId,
    m.role,
    m.content ?? "",
    m.modelId ?? null,
    m.modelName ?? null,
    m.provider ?? null,
    m.generationId ?? null,
    m.status ?? "completed",
    Date.now()
  );
  return getMessage(id)!;
}

/** Walk parent pointers from a leaf to the root: the active thread, oldest first. */
export function threadToLeaf(conversationId: string, leafId: string | null): MessageRow[] {
  if (!leafId) return [];
  const byId = new Map(listMessages(conversationId).map((m) => [m.id, m]));
  const thread: MessageRow[] = [];
  let cursor = byId.get(leafId);
  while (cursor) {
    thread.push(cursor);
    cursor = cursor.parent_id ? byId.get(cursor.parent_id) : undefined;
  }
  return thread.reverse();
}