package main

import (
	"context"
	"log"
	"sort"
	"time"
)

func (this *Application) sync(ctx context.Context) (bool, error) {

	// List repositories on Gitea
	repos, err := this.repos(ctx)
	if err != nil {
		return false, err
	}

	// Compare this list of repositories to our existing one
	// If the repository is new, or if it's update-time has changed since we last
	// saw it, then re-refresh its real git commit timestamps
	// Otherwise copy them from the previous version

	this.reposMut.RLock() // readonly

	anyChanges := false
	if len(repos) != len(this.reposCache) {
		anyChanges = true
	}

	for i, rr := range repos {
		if idx, ok := this.reposAlphabeticalOrder[rr.Name]; ok && this.reposCache[idx].GiteaUpdated == rr.GiteaUpdated {
			// Already exists in cache with same Gitea update time
			// Copy timestamps
			repos[i] = this.reposCache[idx]

		} else {

			// New repo, or Gitea has updated timestamp
			anyChanges = true

			// Refresh timestamps
			this.populateCommitInfo(ctx, &rr)

			// Refresh topics
			if t, err := this.topicsForRepo(ctx, rr.Name); err == nil {
				rr.topics = t
			}

			// Save
			repos[i] = rr
		}
	}

	this.reposMut.RUnlock()

	//
	if !anyChanges {
		return false, nil // nothing to do
	}

	// We have a final updated repos array

	// Sort repos once alphabetically, to get alphabetical indexes...
	sort.Slice(repos, func(i, j int) bool {
		return repos[i].Name < repos[j].Name
	})
	alphabeticalOrderIndexes := make(map[string]int, len(repos))
	for idx, repo := range repos {
		alphabeticalOrderIndexes[repo.Name] = idx
	}

	// But then make sure the final sort is by most-recently-created
	sort.Slice(repos, func(i, j int) bool {
		return repos[i].GiteaCreated.After(repos[j].GiteaCreated)
	})

	// Commit our changes for the other threads to look at
	this.reposMut.Lock()
	this.reposCache = repos
	this.reposAlphabeticalOrder = alphabeticalOrderIndexes
	this.reposMut.Unlock()

	// Done
	return true, nil
}

func (this *Application) syncWorker(ctx context.Context) {

	t := time.NewTicker(30 * time.Minute)
	defer t.Stop()

	for {
		anyChanges, err := this.sync(ctx)
		if err != nil {
			// log and continue
			log.Printf("Refreshing repositories: %s", err.Error())
		}
		if anyChanges {
			log.Printf("Repositories updated")
		}

		select {
		case <-t.C:
			continue

		case <-ctx.Done():
			return
		}
	}
}