package service

import (
	"context"
	"encoding/json"
	"fmt"
	"sync"
	"time"

	"github.com/gochat/gochat/internal/model"
	"github.com/gochat/gochat/internal/worker"
)

const TaskTypeReportingRollupDay = "reporting:rollup_day"

type reportingRollupDayJob struct {
	AccountID uint   `json:"account_id"`
	Date      string `json:"date"`
}

var reportingRollupRegistrations sync.Map

func RegisterReportingRollupJobs(wp *worker.WorkerPool, svc *AnalyticsService) {
	if wp == nil || svc == nil {
		return
	}
	if _, loaded := reportingRollupRegistrations.LoadOrStore(wp, struct{}{}); loaded {
		return
	}
	wp.Register(TaskTypeReportingRollupDay, svc.performReportingRollupDayJob)
}

func EnqueueReportingRollupDay(ctx context.Context, wp *worker.WorkerPool, accountID uint, date time.Time) (*model.BackgroundJob, error) {
	if wp == nil || accountID == 0 {
		return nil, nil
	}
	day := time.Date(date.Year(), date.Month(), date.Day(), 0, 0, 0, 0, time.UTC)
	dateStr := day.Format(time.DateOnly)
	return wp.Enqueue(ctx, TaskTypeReportingRollupDay, reportingRollupDayJob{AccountID: accountID, Date: dateStr},
		worker.WithQueue("low"),
		worker.WithMaxAttempts(3),
		worker.WithIdempotencyKey(fmt.Sprintf("reporting:rollup_day:%d:%s", accountID, dateStr)),
	)
}

func (s *AnalyticsService) performReportingRollupDayJob(ctx context.Context, job *model.BackgroundJob) error {
	var payload reportingRollupDayJob
	if err := json.Unmarshal(job.Payload, &payload); err != nil {
		return fmt.Errorf("unmarshal reporting rollup job: %w", err)
	}
	if payload.AccountID == 0 || payload.Date == "" {
		return fmt.Errorf("invalid reporting rollup payload: %#v", payload)
	}
	date, err := time.Parse(time.DateOnly, payload.Date)
	if err != nil {
		return fmt.Errorf("parse reporting rollup date: %w", err)
	}
	if s == nil || s.rollups == nil {
		return fmt.Errorf("reporting rollup service is required")
	}
	return s.rollups.ComputeDailyRollup(ctx, payload.AccountID, date)
}