import { pool } from '../../../db/pool.js';

const TABLE = { page: 'pages', ref: 'refs', task: 'tasks', conversation: 'conversations' };

export const readTool = {
  name: 'read',
  description: 'Read a single entity (page, ref, task, conversation) by id for grounding.',
  input_schema: {
    type: 'object',
    properties: {
      kind: { type: 'string', enum: ['page', 'ref', 'task', 'conversation'] },
      id: { type: 'string', description: 'uuid of the entity' }
    },
    required: ['kind', 'id']
  },
  async handler({ kind, id }, ctx = {}) {
    const table = TABLE[kind];
    if (!table) return { error: `unknown kind "${kind}"` };
    const { rows: [row] } = await pool.query(`SELECT * FROM ${table} WHERE id=$1`, [id]);
    if (!row) return { error: `${kind} ${id} not found` };
    // Space scoping. When a Space is bound (external scoped agents — and Dross,
    // which operates within one Space), an entity that carries space_id must
    // match it. Kinds without a space_id column (conversations) can't be proven
    // in-scope, so they're denied to spaceScoped callers (external agents) only.
    // Owner/Dross with no bound Space (ctx.space_id == null) → unrestricted.
    if (ctx.space_id != null) {
      if (row.space_id !== undefined) {
        if (row.space_id !== ctx.space_id) return { error: `${kind} ${id} not found` };
      } else if (ctx.spaceScoped) {
        return { error: `${kind} ${id} not found` };
      }
    }
    return row;
  }
};