import { z } from 'zod';

import { getSessionList, sessionService } from '@openpanel/db';
import { zChartEventFilter } from '@openpanel/validation';

import { createTRPCRouter, protectedProcedure } from '../trpc';

export function encodeCursor(cursor: {
  createdAt: string;
  id: string;
}): string {
  const json = JSON.stringify(cursor);
  return Buffer.from(json, 'utf8').toString('base64url'); // URL-safe
}

export function decodeCursor(
  encoded: string,
): { createdAt: string; id: string } | null {
  try {
    const json = Buffer.from(encoded, 'base64url').toString('utf8');
    const obj = JSON.parse(json);
    if (typeof obj.createdAt === 'string' && typeof obj.id === 'string') {
      return obj;
    }
    return null;
  } catch {
    return null;
  }
}

export const sessionRouter = createTRPCRouter({
  list: protectedProcedure
    .input(
      z.object({
        projectId: z.string(),
        profileId: z.string().optional(),
        cursor: z.string().nullish(),
        filters: z.array(zChartEventFilter).default([]),
        startDate: z.date().optional(),
        endDate: z.date().optional(),
        search: z.string().optional(),
        take: z.number().default(50),
      }),
    )
    .query(async ({ input }) => {
      const cursor = input.cursor ? decodeCursor(input.cursor) : null;
      const data = await getSessionList({
        ...input,
        cursor,
      });
      return {
        data: data.items,
        meta: {
          next: data.meta.next ? encodeCursor(data.meta.next) : undefined,
        },
      };
    }),

  byId: protectedProcedure
    .input(z.object({ sessionId: z.string(), projectId: z.string() }))
    .query(async ({ input: { sessionId, projectId } }) => {
      return sessionService.byId(sessionId, projectId);
    }),
});