package update

import (
	domain "RenewCMS/internal/domain/update"
	"encoding/json"
	"os"
	"path/filepath"
	"sync"
)

type JSONJobStore struct {
	path string
	mu   sync.Mutex
}

var _ domain.JobStore = &JSONJobStore{}

func NewJSONJobStore(path string) *JSONJobStore {
	store := &JSONJobStore{path: path}
	store.failInterruptedJob()
	return store
}

func (s *JSONJobStore) failInterruptedJob() {
	job, found := s.read()
	if !found || !job.IsRunning() {
		return
	}
	job.State = domain.StateFailed
	job.Error = domain.ErrorKindDownload
	job.DownloadedBytes = 0
	job.TotalBytes = 0
	_ = s.write(job)
}

func (s *JSONJobStore) Load() (domain.Job, bool) {
	s.mu.Lock()
	defer s.mu.Unlock()

	job, found := s.read()
	if !found {
		return domain.Job{}, false
	}
	if job.State == domain.StateReady && !fileExists(job.StagedBinary) {
		return domain.Job{}, false
	}
	return job, true
}

func (s *JSONJobStore) Save(job domain.Job) error {
	s.mu.Lock()
	defer s.mu.Unlock()

	return s.write(job)
}

func (s *JSONJobStore) read() (domain.Job, bool) {
	content, err := os.ReadFile(s.path)
	if err != nil {
		return domain.Job{}, false
	}
	var job domain.Job
	if err := json.Unmarshal(content, &job); err != nil || job.State == "" {
		return domain.Job{}, false
	}
	return job, true
}

func (s *JSONJobStore) write(job domain.Job) error {
	content, err := json.Marshal(job)
	if err != nil {
		return err
	}
	if err := os.MkdirAll(filepath.Dir(s.path), os.ModePerm); err != nil {
		return err
	}
	temporary := s.path + ".tmp"
	if err := os.WriteFile(temporary, content, statusFilePermissions); err != nil {
		return err
	}
	return os.Rename(temporary, s.path)
}

func fileExists(path string) bool {
	if path == "" {
		return false
	}
	info, err := os.Stat(path)
	return err == nil && !info.IsDir()
}