/*
Copyright © 2023 Philipp Wolfer <phw@uploadedlobster.com>

This file is part of Scotty.

Scotty is free software: you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation, either version 3 of the License, or (at your option) any later version.

Scotty is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with
Scotty. If not, see <https://www.gnu.org/licenses/>.
*/
package cmd

import (
	"fmt"
	"sync"
	"time"

	"github.com/spf13/cobra"
	"github.com/spf13/viper"
	"go.uploadedlobster.com/scotty/internal/backends"
	"go.uploadedlobster.com/scotty/internal/models"
	"go.uploadedlobster.com/scotty/internal/storage"
)

// lovesCmd represents the loves command
var lovesCmd = &cobra.Command{
	Use:   "loves",
	Short: "Transfer loves between two services",
	Long:  `Transfers loves between two configured services.`,
	Run: func(cmd *cobra.Command, args []string) {
		sourceName, sourceConfig := getConfigFromFlag(cmd, "from")
		targetName, targetConfig := getConfigFromFlag(cmd, "to")
		fmt.Printf("Transferring loves from %s to %s...\n", sourceName, targetName)

		// Setup database
		db, err := storage.New(viper.GetString("database"))
		cobra.CheckErr(err)

		// Initialize backends
		exportBackend, err := backends.ResolveBackend[models.LovesExport](sourceConfig)
		cobra.CheckErr(err)
		importBackend, err := backends.ResolveBackend[models.LovesImport](targetConfig)
		cobra.CheckErr(err)

		// Authenticate backends, if needed
		_, err = backends.Authenticate(sourceName, exportBackend, db, viper.GetViper())
		cobra.CheckErr(err)

		_, err = backends.Authenticate(targetName, importBackend, db, viper.GetViper())
		cobra.CheckErr(err)

		// Read timestamp
		timestamp := time.Unix(getInt64FromFlag(cmd, "timestamp"), 0)
		if timestamp == time.Unix(0, 0) {
			timestamp, err = db.GetImportTimestamp(sourceName, targetName, "loves")
			cobra.CheckErr(err)
		}
		fmt.Printf("From timestamp: %v (%v)\n", timestamp, timestamp.Unix())

		// Prepare progress bars
		exportProgress := make(chan models.Progress)
		importProgress := make(chan models.Progress)
		var wg sync.WaitGroup
		progress := progressBar(&wg, exportProgress, importProgress)

		// Export from source
		exportChan := make(chan models.LovesResult, 1000)
		go exportBackend.ExportLoves(timestamp, exportChan, exportProgress)

		// Import into target
		resultChan := make(chan models.ImportResult)
		var processor = backends.LovesImportProcessor{
			Backend: importBackend,
		}
		go processor.Process(exportChan, resultChan, importProgress)
		result := <-resultChan
		close(exportProgress)
		wg.Wait()
		progress.Wait()
		if result.Error != nil {
			fmt.Printf("Import failed, last reported timestamp was %v (%v)\n", result.LastTimestamp, result.LastTimestamp.Unix())
			cobra.CheckErr(result.Error)
		}
		fmt.Printf("Imported %v of %v loves into %v.\n",
			result.ImportCount, result.TotalCount, targetName)

		// Update timestamp
		if result.LastTimestamp.Unix() < timestamp.Unix() {
			result.LastTimestamp = timestamp
		}
		fmt.Printf("Latest timestamp: %v (%v)\n", result.LastTimestamp, result.LastTimestamp.Unix())
		err = db.SetImportTimestamp(sourceName, targetName, "loves", result.LastTimestamp)
		cobra.CheckErr(err)

		// Print errors
		if len(result.ImportErrors) > 0 {
			fmt.Printf("\nDuring the import the following errors occurred:\n")
			for _, err := range result.ImportErrors {
				fmt.Printf("Error: %v\n", err)
			}
		}
	},
}

func init() {
	beamCmd.AddCommand(lovesCmd)

	// Here you will define your flags and configuration settings.

	// Cobra supports Persistent Flags which will work for this command
	// and all subcommands, e.g.:
	// lovesCmd.PersistentFlags().String("foo", "", "A help for foo")

	// Cobra supports local flags which will only run when this command
	// is called directly, e.g.:
	// lovesCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")
}