// Package wifi_service reads the collector's latest snapshot without LAN access.
package wifi_service

import (
	"context"
	"encoding/json"
	"io"
	"os"
	"time"

	"evening_detective_server/internal/modules/cudy"
)

type Service struct {
	path string
	now  func() time.Time
}

func New(path string) *Service { return &Service{path: path, now: time.Now} }

func (s *Service) Get(ctx context.Context) (cudy.Snapshot, bool) {
	if s == nil || s.path == "" {
		return cudy.Snapshot{}, false
	}
	snapshot := cudy.Snapshot{Enabled: true, HasError: true}
	if ctx.Err() != nil {
		return snapshot, true
	}
	file, err := os.Open(s.path)
	if err != nil {
		return snapshot, true
	}
	defer file.Close()
	data, err := io.ReadAll(io.LimitReader(file, 2<<20+1))
	if err != nil || len(data) > 2<<20 || json.Unmarshal(data, &snapshot) != nil {
		return cudy.Snapshot{Enabled: true, HasError: true}, true
	}
	if !snapshot.Enabled {
		return snapshot, false
	}
	stale := snapshot.HasError || snapshot.CollectedAt.IsZero() || s.now().Sub(snapshot.CollectedAt) >= 30*time.Second || snapshot.CollectedAt.After(s.now())
	return snapshot, stale
}