package cron

import (
	"fmt"

	"github.com/tribalwarshelp/shared/models"
	"github.com/tribalwarshelp/shared/utils"

	"github.com/go-pg/pg/v10"
	"github.com/robfig/cron/v3"
	"github.com/sirupsen/logrus"
)

var log = logrus.WithField("package", "cron")

type Config struct {
	DB                   *pg.DB
	MaxConcurrentWorkers int
	RunOnStartup         bool
}

func Attach(c *cron.Cron, cfg Config) error {
	if cfg.DB == nil {
		return fmt.Errorf("cfg.DB cannot be nil, expected *pg.DB")
	}

	h := &handler{db: cfg.DB, maxConcurrentWorkers: cfg.MaxConcurrentWorkers}
	if err := h.init(); err != nil {
		return err
	}

	versions := []*models.Version{}
	if err := cfg.DB.Model(&versions).DistinctOn("timezone").Select(); err != nil {
		return err
	}

	updateServerData := utils.TrackExecutionTime(log, h.updateServerData, "updateServerData")
	vacuumDatabase := utils.TrackExecutionTime(log, h.vacuumDatabase, "vacuumDatabase")
	updateHistoryFuncs := []func(){}
	updateStatsFuncs := []func(){}
	for _, version := range versions {
		updateHistory := utils.TrackExecutionTime(log,
			createFnWithTimezone(version.Timezone, h.updateHistory),
			fmt.Sprintf("%s: updateHistory", version.Timezone))
		updateHistoryFuncs = append(updateHistoryFuncs, updateHistory)

		updateStats := utils.TrackExecutionTime(log,
			createFnWithTimezone(version.Timezone, h.updateStats),
			fmt.Sprintf("%s: updateStats", version.Timezone))
		updateStatsFuncs = append(updateStatsFuncs, updateStats)

		if _, err := c.AddFunc(fmt.Sprintf("CRON_TZ=%s 30 1 * * *", version.Timezone), updateHistory); err != nil {
			return err
		}
		if _, err := c.AddFunc(fmt.Sprintf("CRON_TZ=%s 45 1 * * *", version.Timezone), updateStats); err != nil {
			return err
		}
	}
	if _, err := c.AddFunc("0 * * * *", updateServerData); err != nil {
		return err
	}
	if _, err := c.AddFunc("20 1 * * *", vacuumDatabase); err != nil {
		return err
	}
	if cfg.RunOnStartup {
		go func() {
			updateServerData()
			vacuumDatabase()
			for _, fn := range updateHistoryFuncs {
				go fn()
			}
			for _, fn := range updateStatsFuncs {
				go fn()
			}
		}()
	}

	return nil
}