moth/cmd/mothd/mothballs.go

199 lines
4.5 KiB
Go

package main
import (
"archive/zip"
"bufio"
"fmt"
"io"
"log"
"sort"
"strconv"
"strings"
"sync"
"time"
"github.com/spf13/afero"
"github.com/spf13/afero/zipfs"
)
type zipCategory struct {
afero.Fs
io.Closer
mtime time.Time
}
// Mothballs provides a collection of active mothball files (puzzle categories)
type Mothballs struct {
afero.Fs
categories map[string]zipCategory
categoryLock *sync.RWMutex
}
// NewMothballs returns a new Mothballs structure backed by the provided directory
func NewMothballs(fs afero.Fs) *Mothballs {
return &Mothballs{
Fs: fs,
categories: make(map[string]zipCategory),
categoryLock: new(sync.RWMutex),
}
}
func (m *Mothballs) getCat(cat string) (zipCategory, bool) {
m.categoryLock.RLock()
defer m.categoryLock.RUnlock()
ret, ok := m.categories[cat]
return ret, ok
}
// Open returns a ReadSeekCloser corresponding to the filename in a puzzle's category and points
func (m *Mothballs) Open(cat string, points int, filename string) (ReadSeekCloser, time.Time, error) {
zc, ok := m.getCat(cat)
if !ok {
return nil, time.Time{}, fmt.Errorf("no such category: %s", cat)
}
f, err := zc.Open(fmt.Sprintf("%d/%s", points, filename))
if err != nil {
return nil, time.Time{}, err
}
fInfo, err := f.Stat()
return f, fInfo.ModTime(), err
}
// Inventory returns the list of current categories
func (m *Mothballs) Inventory() []Category {
m.categoryLock.RLock()
defer m.categoryLock.RUnlock()
categories := make([]Category, 0, 20)
for cat, zfs := range m.categories {
pointsList := make([]int, 0, 20)
pf, err := zfs.Open("puzzles.txt")
if err != nil {
// No puzzles = no category
continue
}
scanner := bufio.NewScanner(pf)
for scanner.Scan() {
line := scanner.Text()
if pointval, err := strconv.Atoi(line); err != nil {
log.Printf("Reading points for %s: %s", cat, err.Error())
} else {
pointsList = append(pointsList, pointval)
}
}
sort.Ints(pointsList)
categories = append(categories, Category{cat, pointsList})
}
return categories
}
// CheckAnswer returns an error if the provided answer is in any way incorrect for the given category and points
func (m *Mothballs) CheckAnswer(cat string, points int, answer string) (bool, error) {
zfs, ok := m.getCat(cat)
if !ok {
return false, fmt.Errorf("no such category: %s", cat)
}
af, err := zfs.Open("answers.txt")
if err != nil {
return false, fmt.Errorf("no answers.txt file")
}
defer af.Close()
needle := fmt.Sprintf("%d %s", points, answer)
scanner := bufio.NewScanner(af)
for scanner.Scan() {
if scanner.Text() == needle {
return true, nil
}
}
return false, nil
}
// refresh refreshes internal state.
// It looks for changes to the directory listing, and caches any new mothballs.
func (m *Mothballs) refresh() {
m.categoryLock.Lock()
defer m.categoryLock.Unlock()
// Any new categories?
files, err := afero.ReadDir(m.Fs, "/")
if err != nil {
log.Println("Error listing mothballs:", err)
return
}
found := make(map[string]bool)
for _, f := range files {
filename := f.Name()
if !strings.HasSuffix(filename, ".mb") {
continue
}
categoryName := strings.TrimSuffix(filename, ".mb")
found[categoryName] = true
reopen := false
if existingMothball, ok := m.categories[categoryName]; !ok {
reopen = true
} else if si, err := m.Fs.Stat(filename); err != nil {
log.Println(err)
} else if si.ModTime().After(existingMothball.mtime) {
existingMothball.Close()
delete(m.categories, categoryName)
reopen = true
}
if reopen {
f, err := m.Fs.Open(filename)
if err != nil {
log.Println(err)
continue
}
fi, err := f.Stat()
if err != nil {
f.Close()
log.Println(err)
continue
}
zrc, err := zip.NewReader(f, fi.Size())
if err != nil {
f.Close()
log.Println(err)
continue
}
m.categories[categoryName] = zipCategory{
Fs: zipfs.New(zrc),
Closer: f,
}
log.Println("Adding category:", categoryName)
}
}
// Delete anything in the list that wasn't found
for categoryName, zc := range m.categories {
if !found[categoryName] {
zc.Close()
delete(m.categories, categoryName)
log.Println("Removing category:", categoryName)
}
}
}
// Mothball just returns an error
func (m *Mothballs) Mothball(cat string, w io.Writer) error {
return fmt.Errorf("refusing to repackage a compiled mothball")
}
// Maintain performs housekeeping for Mothballs.
func (m *Mothballs) Maintain(updateInterval time.Duration) {
m.refresh()
for range time.NewTicker(updateInterval).C {
m.refresh()
}
}