/**
 * memory_history tool — extracted from index.ts registerTools().
 *
 * Views the edit history of a specific memory, showing all changes
 * over time including previous values, new values, and timestamps.
 */

import { Type } from "@sinclair/typebox";
import type { ToolContext } from "./index.ts";

// ---------------------------------------------------------------------------
// Tool factory
// ---------------------------------------------------------------------------

/**
 * Creates the `memory_history` tool config object suitable for
 * `api.registerTool(config, { name })`.
 */
export function createMemoryHistoryTool(ctx: ToolContext) {
  const { provider } = ctx;

  return {
    name: "memory_history",
    label: "Memory History",
    description:
      "View the edit history of a specific memory. Shows all changes over time including previous values, new values, and timestamps. Useful for understanding how a memory evolved.",
    parameters: Type.Object({
      memoryId: Type.String({
        description: "The memory ID to view history for",
      }),
    }),

    async execute(_toolCallId: string, params: Record<string, unknown>) {
      const { memoryId } = params as { memoryId: string };

      try {
        const history = await provider!.history(memoryId);

        if (!history || history.length === 0) {
          return {
            content: [
              {
                type: "text",
                text: `No history found for memory ${memoryId}.`,
              },
            ],
            details: { count: 0 },
          };
        }

        const text = history
          .map(
            (h, i) =>
              `${i + 1}. [${h.event}] ${h.created_at}\n   Old: ${h.old_memory || "(none)"}\n   New: ${h.new_memory || "(none)"}`,
          )
          .join("\n\n");

        return {
          content: [
            {
              type: "text",
              text: `History for memory ${memoryId} (${history.length} entries):\n\n${text}`,
            },
          ],
          details: { count: history.length, history },
        };
      } catch (err) {
        return {
          content: [
            { type: "text", text: `Memory history failed: ${String(err)}` },
          ],
          details: { error: String(err) },
        };
      }
    },
  };
}