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 func(){
		oneDeepSync.Unlock()
		if DeepSyncProgress != 255 {
			log.Printf("Full synchronization terminated at step %d/255", DeepSyncProgress)
		}
	}()
	DeepSyncProgress = 1

	errs = map[string][]string{}

	startTime := time.Now()
	errs["_date"] = []string{fmt.Sprintf("%v", startTime)}
	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 {
					log.Printf("Full synchronization in progress: %d/255 - doing Theme %q, Exercice %q: %q\n", DeepSyncProgress, theme.Name, exercice.Title, exercice.Path)

					DeepSyncProgress = 3 + uint8(tid) * themeStep + uint8(eid) * exerciceStep
					errs[theme.Name] = append(errs[theme.Name], SyncExerciceFiles(i, exercice)...)

					DeepSyncProgress += exerciceStep / 3
					flagsBindings, ferrs := SyncExerciceFlags(i, exercice)
					errs[theme.Name] = append(errs[theme.Name], ferrs...)

					DeepSyncProgress += exerciceStep / 3
					_, herrs := SyncExerciceHints(i, exercice, flagsBindings)
					errs[theme.Name] = append(errs[theme.Name], herrs...)
				}
			}
		}
	}

	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()

		if out, err := json.Marshal(errs); err == nil {
			fdto.Write(out)
		} else {
			errs["_regeneration"] = append(errs["_regeneration"], err.Error())
			log.Println(err)
		}
	} 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
	log.Println("Full synchronization done in", time.Since(startTime))
	return
}