/**
 * flow-engine 存储 adapter —— Drizzle 只准出现在 adapter(编码规范 §5.3)。
 */
import { eq } from 'drizzle-orm';
import type { FlowModel, TaskId } from '@contracts';
import { flowModelSchema } from '@contracts';
import type { Db } from '@shared/db.ts';
import type { FlowStateStore } from '../../port.ts';
import type { FlowPosition } from '../domain/step-sequence.ts';
import { flowStateTable } from './flow-state-schema.ts';

export function createFlowStateStore(db: Db): FlowStateStore {
  return {
    async save(taskId: TaskId, model: FlowModel, position: FlowPosition) {
      await db
        .insert(flowStateTable)
        .values({ taskId, model, position, updatedAt: new Date() })
        .onConflictDoUpdate({
          target: flowStateTable.taskId,
          set: { model, position, updatedAt: new Date() },
        });
    },
    async load(taskId: TaskId) {
      const rows = await db.select().from(flowStateTable).where(eq(flowStateTable.taskId, taskId)).limit(1);
      const row = rows[0];
      if (row === undefined) return undefined;
      return { model: flowModelSchema.parse(row.model), position: row.position as FlowPosition };
    },
  };
}