package sync

import (
	"encoding/json"
	"fmt"
	"log"
	"os"
	"time"
	"sync"

	"srs.epita.fr/fic-server/libfic"
	"srs.epita.fr/fic-server/settings"
)

// DeepReportPath stores the path to the report generated during full recursive import.
var DeepReportPath = "full_import_report.json"

// oneDeepSync ensure there is no more than one running deep sync.
var oneDeepSync sync.Mutex

// DeepSyncProgress expose the progression of the depp synchronization (0 = 0%, 255 = 100%).
var DeepSyncProgress uint8

// SyncDeep performs a recursive synchronisation: from themes to challenge items.
func SyncDeep(i Importer) (errs map[string][]string) {
	oneDeepSync.Lock()
	defer oneDeepSync.Unlock()
	DeepSyncProgress = 1

	errs = map[string][]string{}

	errs["_date"] = []string{fmt.Sprintf("%v", time.Now())}
	errs["_themes"] = SyncThemes(i)

	if themes, err := fic.GetThemes(); err == nil {
		DeepSyncProgress = 2
		var themeStep uint8 = uint8(250) / uint8(len(themes))

		for tid, theme := range themes {
			DeepSyncProgress = 3 + uint8(tid) * themeStep
			errs[theme.Name] = SyncExercices(i, theme)

			if exercices, err := theme.GetExercices(); err == nil {
				var exerciceStep uint8 = themeStep / uint8(len(exercices))
				for eid, exercice := range exercices {
					DeepSyncProgress = 3 + uint8(tid) * themeStep + uint8(eid) * exerciceStep
					errs[theme.Name] = append(errs[theme.Name], SyncExerciceFiles(i, exercice)...)
					DeepSyncProgress += exerciceStep / 3
					errs[theme.Name] = append(errs[theme.Name], SyncExerciceFlags(i, exercice)...)
					DeepSyncProgress += exerciceStep / 3
					errs[theme.Name] = append(errs[theme.Name], SyncExerciceHints(i, exercice)...)
				}
			}
		}
	}

	DeepSyncProgress = 254
	errs["_date"] = append(errs["_date"], fmt.Sprintf("%v", time.Now()))

	errs["_regeneration"] = []string{}

	if fdto, err := os.Create(DeepReportPath); err == nil {
		defer fdto.Close()

		fdto.Write([]byte("disp("))
		if out, err := json.Marshal(errs); err == nil {
			fdto.Write(out)
		} else {
			errs["_regeneration"] = append(errs["_regeneration"], err.Error())
			log.Println(err)
		}
		fdto.Write([]byte(");"))
	} else {
		errs["_regeneration"] = append(errs["_regeneration"], err.Error())
		log.Println(err)
	}

	if err := settings.ForceRegeneration(); err != nil {
		errs["_regeneration"] = append(errs["_regeneration"], err.Error())
	}

	DeepSyncProgress = 255
	return
}