exports.up = async function (knex) {
  await knex.schema.createTable('ai_processes', (table) => {
    table.uuid('id').primary();
    table.string('tenant_id').notNullable();
    table.string('name').notNullable();
    table.text('description');
    table.integer('latest_version').notNullable().defaultTo(1);
    table.string('created_by').notNullable();
    table.timestamp('created_at').defaultTo(knex.fn.now());
    table.timestamp('updated_at').defaultTo(knex.fn.now());
    table.index(['tenant_id']);
  });

  await knex.schema.createTable('ai_process_versions', (table) => {
    table.uuid('id').primary();
    table.string('tenant_id').notNullable();
    table.uuid('process_id').notNullable();
    table.integer('version').notNullable();
    table.json('graph_json').notNullable();
    table.json('compiled_json').notNullable();
    table.string('created_by').notNullable();
    table.timestamp('created_at').defaultTo(knex.fn.now());
    table.unique(['process_id', 'version']);
    table.index(['tenant_id']);
    table.index(['process_id']);
  });

  await knex.schema.createTable('ai_process_runs', (table) => {
    table.uuid('id').primary();
    table.string('tenant_id').notNullable();
    table.uuid('process_id').notNullable();
    table.integer('version').notNullable();
    table.string('status').notNullable();
    table.json('input_json').notNullable();
    table.json('output_json');
    table.json('error_json');
    table.json('state_json');
    table.string('current_node_id');
    table.timestamp('started_at').defaultTo(knex.fn.now());
    table.timestamp('ended_at');
    table.index(['tenant_id']);
    table.index(['process_id']);
  });

  await knex.schema.createTable('ai_chat_sessions', (table) => {
    table.uuid('id').primary();
    table.string('tenant_id').notNullable();
    table.string('user_id').notNullable();
    table.timestamp('created_at').defaultTo(knex.fn.now());
    table.index(['tenant_id']);
    table.index(['user_id']);
  });

  await knex.schema.createTable('ai_chat_messages', (table) => {
    table.uuid('id').primary();
    table.uuid('session_id').notNullable();
    table.string('role').notNullable();
    table.text('content').notNullable();
    table.timestamp('created_at').defaultTo(knex.fn.now());
    table.index(['session_id']);
  });

  await knex.schema.createTable('ai_audit_events', (table) => {
    table.uuid('id').primary();
    table.string('tenant_id').notNullable();
    table.uuid('run_id').notNullable();
    table.string('event_type').notNullable();
    table.json('payload_json').notNullable();
    table.timestamp('created_at').defaultTo(knex.fn.now());
    table.index(['tenant_id']);
    table.index(['run_id']);
  });
};

exports.down = async function (knex) {
  await knex.schema.dropTableIfExists('ai_audit_events');
  await knex.schema.dropTableIfExists('ai_chat_messages');
  await knex.schema.dropTableIfExists('ai_chat_sessions');
  await knex.schema.dropTableIfExists('ai_process_runs');
  await knex.schema.dropTableIfExists('ai_process_versions');
  await knex.schema.dropTableIfExists('ai_processes');
};