cheekylist/main.go
2025-07-25 16:27:30 +02:00

875 lines
23 KiB
Go

package main
import (
"database/sql"
"embed"
"encoding/json"
"fmt"
"io/fs"
"log"
"net/http"
"os"
"strconv"
"strings"
"sync"
"time"
"github.com/google/uuid"
_ "github.com/mattn/go-sqlite3"
)
//go:embed frontend/dist
var staticFiles embed.FS
// ==== Models ====
type Checklist struct {
UUID string `json:"uuid"`
Name string `json:"name"`
}
type ChecklistItem struct {
ID int `json:"id"`
Content string `json:"content"`
Checked bool `json:"checked"`
ParentID *int `json:"parent_id"`
LockedBy *string `json:"locked_by,omitempty"`
LockUntil *time.Time `json:"lock_until,omitempty"`
Checklist string `json:"checklist_uuid"`
Dependencies []int `json:"dependencies,omitempty"`
NotBefore *time.Time `json:"not_before,omitempty"`
NotAfter *time.Time `json:"not_after,omitempty"`
}
type ItemLock struct {
LockedBy string
Expires time.Time
ChecklistUUID string
}
// ==== Globals ====
var (
sseClients = make(map[string]map[chan string]bool) // checklist uuid → set of client channels
sseClientsMutex sync.Mutex
itemLocks = make(map[int]*ItemLock) // item ID → lock
itemLocksMutex sync.Mutex
)
// ==== Database ====
func getChecklistDB(uuid string) (*sql.DB, error) {
// Ensure data directory exists
if err := os.MkdirAll("data", 0755); err != nil {
return nil, err
}
dbPath := fmt.Sprintf("data/%s.db", uuid)
db, err := sql.Open("sqlite3", dbPath)
if err != nil {
return nil, err
}
// Setup schema for this checklist
queries := []string{
`CREATE TABLE IF NOT EXISTS checklist_info (
uuid TEXT PRIMARY KEY,
name TEXT NOT NULL
);`,
`CREATE TABLE IF NOT EXISTS items (
id INTEGER PRIMARY KEY AUTOINCREMENT,
content TEXT NOT NULL,
checked INTEGER NOT NULL,
parent_id INTEGER,
not_before TEXT,
not_after TEXT,
FOREIGN KEY(parent_id) REFERENCES items(id)
);`,
`CREATE TABLE IF NOT EXISTS dependencies (
item_id INTEGER NOT NULL,
dependency_id INTEGER NOT NULL,
PRIMARY KEY (item_id, dependency_id),
FOREIGN KEY(item_id) REFERENCES items(id) ON DELETE CASCADE,
FOREIGN KEY(dependency_id) REFERENCES items(id) ON DELETE CASCADE,
CHECK(item_id != dependency_id)
);`,
}
for _, q := range queries {
if _, err := db.Exec(q); err != nil {
db.Close()
return nil, err
}
}
return db, nil
}
func loadItemDependencies(db *sql.DB, itemID int) ([]int, error) {
rows, err := db.Query(`SELECT dependency_id FROM dependencies WHERE item_id = ?`, itemID)
if err != nil {
return nil, err
}
defer rows.Close()
var deps []int
for rows.Next() {
var depID int
err = rows.Scan(&depID)
if err != nil {
return nil, err
}
deps = append(deps, depID)
}
return deps, nil
}
// ensureChecklistExists creates a checklist if it doesn't exist
func ensureChecklistExists(uuid string) error {
db, err := getChecklistDB(uuid)
if err != nil {
return err
}
defer db.Close()
// Check if checklist_info table has any data
var count int
err = db.QueryRow(`SELECT COUNT(*) FROM checklist_info`).Scan(&count)
if err != nil {
return err
}
// If no checklist exists, create one with a default name
if count == 0 {
_, err = db.Exec(`INSERT INTO checklist_info (uuid, name) VALUES (?, ?)`, uuid, "Untitled Checklist")
if err != nil {
return err
}
}
return nil
}
func loadChecklistName(uuid string) (string, error) {
db, err := getChecklistDB(uuid)
if err != nil {
return "", err
}
defer db.Close()
rows, err := db.Query(`SELECT name FROM checklist_info WHERE uuid = ?`, uuid)
if err != nil {
return "", err
}
defer rows.Close()
if rows.Next() {
var name string
err = rows.Scan(&name)
if err != nil {
return "", err
}
return name, nil
}
return "", fmt.Errorf("not found")
}
func loadChecklistItems(uuid string) ([]ChecklistItem, error) {
db, err := getChecklistDB(uuid)
if err != nil {
return nil, err
}
defer db.Close()
rows, err := db.Query(`SELECT id, content, checked, parent_id, not_before, not_after FROM items`)
if err != nil {
return nil, err
}
defer rows.Close()
var items []ChecklistItem
for rows.Next() {
var it ChecklistItem
var checked int
var parentID sql.NullInt64
var notBefore sql.NullString
var notAfter sql.NullString
err = rows.Scan(&it.ID, &it.Content, &checked, &parentID, &notBefore, &notAfter)
if err != nil {
return nil, err
}
it.Checked = checked != 0
if parentID.Valid {
v := int(parentID.Int64)
it.ParentID = &v
}
if notBefore.Valid {
if t, err := time.Parse(time.RFC3339, notBefore.String); err == nil {
it.NotBefore = &t
}
}
if notAfter.Valid {
if t, err := time.Parse(time.RFC3339, notAfter.String); err == nil {
it.NotAfter = &t
}
}
it.Checklist = uuid
// Load dependencies for this item
deps, err := loadItemDependencies(db, it.ID)
if err != nil {
return nil, err
}
it.Dependencies = deps
// Attach lock info if present
itemLocksMutex.Lock()
if lock, ok := itemLocks[it.ID]; ok && lock.Expires.After(time.Now()) {
it.LockedBy = &lock.LockedBy
t := lock.Expires
it.LockUntil = &t
}
itemLocksMutex.Unlock()
items = append(items, it)
}
return items, nil
}
func addChecklist(name string) (string, error) {
uuidStr := uuid.New().String()
db, err := getChecklistDB(uuidStr)
if err != nil {
return "", err
}
defer db.Close()
_, err = db.Exec(`INSERT INTO checklist_info (uuid, name) VALUES (?, ?)`, uuidStr, name)
return uuidStr, err
}
func addItem(uuid, content string, parentID *int, notBefore *time.Time, notAfter *time.Time) (ChecklistItem, error) {
db, err := getChecklistDB(uuid)
if err != nil {
return ChecklistItem{}, err
}
defer db.Close()
var notBeforeStr, notAfterStr *string
if notBefore != nil {
s := notBefore.Format(time.RFC3339)
notBeforeStr = &s
}
if notAfter != nil {
s := notAfter.Format(time.RFC3339)
notAfterStr = &s
}
res, err := db.Exec(`INSERT INTO items (content, checked, parent_id, not_before, not_after) VALUES (?, 0, ?, ?, ?)`,
content, parentID, notBeforeStr, notAfterStr)
if err != nil {
return ChecklistItem{}, err
}
id, _ := res.LastInsertId()
return ChecklistItem{
ID: int(id),
Content: content,
Checked: false,
ParentID: parentID,
NotBefore: notBefore,
NotAfter: notAfter,
Checklist: uuid,
}, nil
}
func updateItem(uuid string, id int, content *string, checked *bool, parentID *int, dependencies *[]int, notBefore *time.Time, notAfter *time.Time) (ChecklistItem, error) {
log.Printf("updateItem called with uuid: %s, id: %d", uuid, id)
log.Printf("Parameters: content=%v, checked=%v, parentID=%v, dependencies=%v", content, checked, parentID, dependencies)
db, err := getChecklistDB(uuid)
if err != nil {
log.Printf("Failed to get database: %v", err)
return ChecklistItem{}, err
}
defer db.Close()
log.Printf("Database connection successful for uuid: %s", uuid)
// If trying to check an item, validate dependencies and date constraints first
if checked != nil && *checked {
log.Printf("Validating dependencies for item %d", id)
deps, err := loadItemDependencies(db, id)
if err != nil {
log.Printf("Failed to load dependencies: %v", err)
return ChecklistItem{}, err
}
// Check if all dependencies are completed
for _, depID := range deps {
var depChecked int
err = db.QueryRow(`SELECT checked FROM items WHERE id = ?`, depID).Scan(&depChecked)
if err != nil {
log.Printf("Failed to check dependency %d: %v", depID, err)
return ChecklistItem{}, err
}
if depChecked == 0 {
return ChecklistItem{}, fmt.Errorf("cannot complete item: dependency %d is not completed", depID)
}
}
// Validate date constraints
now := time.Now()
var notBeforeStr, notAfterStr sql.NullString
err = db.QueryRow(`SELECT not_before, not_after FROM items WHERE id = ?`, id).Scan(&notBeforeStr, &notAfterStr)
if err != nil {
log.Printf("Failed to get date constraints: %v", err)
return ChecklistItem{}, err
}
if notBeforeStr.Valid {
if notBefore, err := time.Parse(time.RFC3339, notBeforeStr.String); err == nil {
if now.Before(notBefore) {
return ChecklistItem{}, fmt.Errorf("cannot complete item: not before %s", notBefore.Format("2006-01-02 15:04:05"))
}
}
}
if notAfterStr.Valid {
if notAfter, err := time.Parse(time.RFC3339, notAfterStr.String); err == nil {
if now.After(notAfter) {
return ChecklistItem{}, fmt.Errorf("cannot complete item: not after %s", notAfter.Format("2006-01-02 15:04:05"))
}
}
}
} else {
log.Printf("Skipping dependency and date validation - checked is %v", checked)
}
log.Printf("About to check dependencies parameter")
// Update dependencies if provided
if dependencies != nil {
log.Printf("Updating dependencies for item %d: %v", id, *dependencies)
// Delete existing dependencies
_, err = db.Exec(`DELETE FROM dependencies WHERE item_id = ?`, id)
if err != nil {
log.Printf("Failed to delete existing dependencies: %v", err)
return ChecklistItem{}, err
}
// Add new dependencies
for _, depID := range *dependencies {
log.Printf("Adding dependency %d for item %d", depID, id)
_, err = db.Exec(`INSERT INTO dependencies (item_id, dependency_id) VALUES (?, ?)`, id, depID)
if err != nil {
log.Printf("Failed to add dependency %d: %v", depID, err)
return ChecklistItem{}, err
}
}
log.Printf("Dependencies updated successfully")
} else {
log.Printf("No dependencies to update")
}
log.Printf("About to build SQL update query")
set := []string{}
args := []interface{}{}
if content != nil {
set = append(set, "content = ?")
args = append(args, *content)
}
if checked != nil {
set = append(set, "checked = ?")
if *checked {
args = append(args, 1)
} else {
args = append(args, 0)
}
}
if parentID != nil {
set = append(set, "parent_id = ?")
args = append(args, *parentID)
}
if notBefore != nil {
set = append(set, "not_before = ?")
args = append(args, notBefore.Format(time.RFC3339))
}
if notAfter != nil {
set = append(set, "not_after = ?")
args = append(args, notAfter.Format(time.RFC3339))
}
if len(set) > 0 {
q := "UPDATE items SET " + strings.Join(set, ", ") + " WHERE id = ?"
args = append(args, id)
log.Printf("SQL query: %s with args: %v", q, args)
_, err = db.Exec(q, args...)
if err != nil {
log.Printf("Failed to execute SQL update: %v", err)
return ChecklistItem{}, err
}
log.Printf("SQL update executed successfully")
} else {
log.Printf("No fields to update in SQL, skipping update query")
}
// Return updated item
log.Printf("Querying updated item %d", id)
rows, err := db.Query(`SELECT id, content, checked, parent_id, not_before, not_after FROM items WHERE id = ?`, id)
if err != nil {
log.Printf("Failed to query updated item: %v", err)
return ChecklistItem{}, err
}
defer rows.Close()
if rows.Next() {
log.Printf("Found item %d in database", id)
var it ChecklistItem
var checkedInt int
var parentID sql.NullInt64
var notBefore sql.NullString
var notAfter sql.NullString
err = rows.Scan(&it.ID, &it.Content, &checkedInt, &parentID, &notBefore, &notAfter)
if err != nil {
log.Printf("Failed to scan updated item: %v", err)
return ChecklistItem{}, err
}
it.Checked = checkedInt != 0
if parentID.Valid {
v := int(parentID.Int64)
it.ParentID = &v
}
if notBefore.Valid {
if t, err := time.Parse(time.RFC3339, notBefore.String); err == nil {
it.NotBefore = &t
}
}
if notAfter.Valid {
if t, err := time.Parse(time.RFC3339, notAfter.String); err == nil {
it.NotAfter = &t
}
}
it.Checklist = uuid
// Load dependencies
deps, err := loadItemDependencies(db, it.ID)
if err != nil {
log.Printf("Failed to load dependencies for return: %v", err)
return ChecklistItem{}, err
}
it.Dependencies = deps
log.Printf("Successfully updated item %d", id)
return it, nil
}
log.Printf("Item %d not found in database", id)
return ChecklistItem{}, fmt.Errorf("not found")
}
func deleteItem(uuid string, id int) error {
db, err := getChecklistDB(uuid)
if err != nil {
return err
}
defer db.Close()
// Delete dependencies that reference this item
_, err = db.Exec(`DELETE FROM dependencies WHERE dependency_id = ?`, id)
if err != nil {
return err
}
// Delete the item itself
_, err = db.Exec(`DELETE FROM items WHERE id = ?`, id)
return err
}
// ==== SSE Broadcast Logic ====
func broadcast(uuid string, msg interface{}) {
js, _ := json.Marshal(msg)
sseClientsMutex.Lock()
for ch := range sseClients[uuid] {
select {
case ch <- string(js):
default:
// skip if channel is full (consider logging in prod!)
}
}
sseClientsMutex.Unlock()
}
// ==== HTTP Handlers ====
func handleGetItems(w http.ResponseWriter, r *http.Request) {
uuid := strings.TrimPrefix(r.URL.Path, "/api/checklists/")
uuid = uuid[:36]
// Ensure checklist exists
if err := ensureChecklistExists(uuid); err != nil {
http.Error(w, "Failed to ensure checklist exists", 500)
return
}
items, err := loadChecklistItems(uuid)
if err != nil {
http.Error(w, "Failed to load items", 500)
return
}
w.Header().Set("Content-Type", "application/json")
json.NewEncoder(w).Encode(map[string]interface{}{
"success": true,
"message": "Items loaded successfully",
"items": items,
})
}
func handleCreateChecklist(w http.ResponseWriter, r *http.Request) {
type Req struct {
Name string `json:"name"`
}
var req Req
if err := json.NewDecoder(r.Body).Decode(&req); err != nil || strings.TrimSpace(req.Name) == "" {
http.Error(w, "Missing name", 400)
return
}
uuid, err := addChecklist(req.Name)
if err != nil {
http.Error(w, "Failed to create checklist", 500)
return
}
w.Header().Set("Content-Type", "application/json")
resp := map[string]interface{}{
"success": true,
"message": "Checklist created successfully",
"uuid": uuid,
}
json.NewEncoder(w).Encode(resp)
}
func handleAddItem(w http.ResponseWriter, r *http.Request) {
uuid := strings.TrimPrefix(r.URL.Path, "/api/checklists/")
uuid = uuid[:36]
// Ensure checklist exists
if err := ensureChecklistExists(uuid); err != nil {
http.Error(w, "Failed to ensure checklist exists", 500)
return
}
type Req struct {
Content string `json:"content"`
ParentID *int `json:"parent_id"`
NotBefore *time.Time `json:"not_before"`
NotAfter *time.Time `json:"not_after"`
}
var req Req
if err := json.NewDecoder(r.Body).Decode(&req); err != nil || strings.TrimSpace(req.Content) == "" {
http.Error(w, "Missing content", 400)
return
}
item, err := addItem(uuid, req.Content, req.ParentID, req.NotBefore, req.NotAfter)
if err != nil {
http.Error(w, "Failed to add item", 500)
return
}
// broadcast
broadcast(uuid, map[string]interface{}{"type": "item_added", "item": item})
w.Header().Set("Content-Type", "application/json")
w.WriteHeader(201)
json.NewEncoder(w).Encode(map[string]interface{}{
"success": true,
"message": "Item added successfully",
"item": item,
})
}
func handleUpdateItem(w http.ResponseWriter, r *http.Request) {
log.Printf("handleUpdateItem called with path: %s", r.URL.Path)
parts := strings.Split(r.URL.Path, "/")
if len(parts) < 6 {
http.Error(w, "Invalid path", 400)
return
}
uuid := parts[3]
id := 0
fmt.Sscanf(parts[5], "%d", &id)
// Ensure checklist exists
if err := ensureChecklistExists(uuid); err != nil {
http.Error(w, "Failed to ensure checklist exists", 500)
return
}
type Req struct {
Content *string `json:"content"`
Checked *bool `json:"checked"`
ParentID *int `json:"parent_id"`
Dependencies *[]int `json:"dependencies"`
NotBefore *time.Time `json:"not_before"`
NotAfter *time.Time `json:"not_after"`
}
var req Req
if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
http.Error(w, "Bad body", 400)
return
}
item, err := updateItem(uuid, id, req.Content, req.Checked, req.ParentID, req.Dependencies, req.NotBefore, req.NotAfter)
if err != nil {
if strings.Contains(err.Error(), "cannot complete item:") {
http.Error(w, err.Error(), 400)
} else {
http.Error(w, "Not found", 404)
}
return
}
broadcast(uuid, map[string]interface{}{"type": "item_updated", "item": item})
w.Header().Set("Content-Type", "application/json")
json.NewEncoder(w).Encode(map[string]interface{}{
"success": true,
"message": "Item updated successfully",
"item": item,
})
}
func handleDeleteItem(w http.ResponseWriter, r *http.Request) {
parts := strings.Split(r.URL.Path, "/")
uuid := parts[3]
id := 0
fmt.Sscanf(parts[5], "%d", &id)
// Ensure checklist exists
if err := ensureChecklistExists(uuid); err != nil {
http.Error(w, "Failed to ensure checklist exists", 500)
return
}
if err := deleteItem(uuid, id); err != nil {
http.Error(w, "Delete failed", 500)
return
}
broadcast(uuid, map[string]interface{}{"type": "item_deleted", "id": id})
w.Header().Set("Content-Type", "application/json")
json.NewEncoder(w).Encode(map[string]interface{}{
"success": true,
"message": "Item deleted successfully",
"id": id,
})
}
func handleLockItem(w http.ResponseWriter, r *http.Request) {
parts := strings.Split(r.URL.Path, "/")
uuid := parts[3]
id := 0
fmt.Sscanf(parts[5], "%d", &id)
// Ensure checklist exists
if err := ensureChecklistExists(uuid); err != nil {
http.Error(w, "Failed to ensure checklist exists", 500)
return
}
type Req struct {
User string `json:"user"`
}
var req Req
if err := json.NewDecoder(r.Body).Decode(&req); err != nil || strings.TrimSpace(req.User) == "" {
http.Error(w, "Missing user", 400)
return
}
expiry := time.Now().Add(15 * time.Second) // e.g. 30 sec lock
itemLocksMutex.Lock()
itemLocks[id] = &ItemLock{LockedBy: req.User, Expires: expiry, ChecklistUUID: uuid}
itemLocksMutex.Unlock()
// Broadcast lock
broadcast(uuid, map[string]interface{}{"type": "item_locked", "id": id, "locked_by": req.User, "expires": expiry})
w.Header().Set("Content-Type", "application/json")
json.NewEncoder(w).Encode(map[string]interface{}{
"success": true,
"message": "Item locked successfully",
"id": id,
"locked_by": req.User,
"expires": expiry,
})
}
func lockExpiryDaemon() {
for {
time.Sleep(1 * time.Second)
now := time.Now()
// Collect expired locks first
var expiredLocks []struct {
id int
uuid string
}
itemLocksMutex.Lock()
for id, lock := range itemLocks {
if lock.Expires.Before(now) {
expiredLocks = append(expiredLocks, struct {
id int
uuid string
}{id: id, uuid: lock.ChecklistUUID})
delete(itemLocks, id)
}
}
itemLocksMutex.Unlock()
// Broadcast unlock events after releasing the mutex
for _, expired := range expiredLocks {
broadcast(expired.uuid, map[string]interface{}{
"type": "item_unlocked",
"id": expired.id,
})
}
}
}
func handleSSE(w http.ResponseWriter, r *http.Request) {
uuid := strings.TrimPrefix(r.URL.Path, "/api/checklists/")
uuid = uuid[:36]
// Ensure checklist exists
if err := ensureChecklistExists(uuid); err != nil {
http.Error(w, "Failed to ensure checklist exists", 500)
return
}
flusher, ok := w.(http.Flusher)
if !ok {
http.Error(w, "Streaming unsupported", http.StatusInternalServerError)
return
}
w.Header().Set("Content-Type", "text/event-stream")
w.Header().Set("Cache-Control", "no-cache")
w.Header().Set("Connection", "keep-alive")
ch := make(chan string, 20)
// Register client
sseClientsMutex.Lock()
if sseClients[uuid] == nil {
sseClients[uuid] = make(map[chan string]bool)
}
sseClients[uuid][ch] = true
sseClientsMutex.Unlock()
defer func() {
sseClientsMutex.Lock()
delete(sseClients[uuid], ch)
sseClientsMutex.Unlock()
close(ch)
}()
// Send full state on connect
items, err := loadChecklistItems(uuid)
name, err2 := loadChecklistName(uuid)
if err == nil && err2 == nil {
msg, _ := json.Marshal(map[string]interface{}{
"type": "full_state",
"items": items,
})
fmt.Fprintf(w, "data: %s\n\n", msg)
flusher.Flush()
msg, _ = json.Marshal(map[string]interface{}{
"type": "checklist_name",
"name": name,
})
fmt.Fprintf(w, "data: %s\n\n", msg)
flusher.Flush()
}
// Forward events
for {
select {
case ev := <-ch:
fmt.Fprintf(w, "data: %s\n\n", ev)
flusher.Flush()
case <-r.Context().Done():
return
}
}
}
// ==== Main + Routing ====
func main() {
// Ensure data directory exists
if err := os.MkdirAll("data", 0755); err != nil {
log.Fatalf("Failed to create data directory: %v", err)
}
go lockExpiryDaemon()
// Register API handlers first
http.HandleFunc("/api/checklists", func(w http.ResponseWriter, r *http.Request) {
if r.Method == "POST" {
handleCreateChecklist(w, r)
} else {
http.NotFound(w, r)
}
})
http.HandleFunc("/api/checklists/", func(w http.ResponseWriter, r *http.Request) {
path := r.URL.Path
log.Printf("API request: %s %s", r.Method, path)
switch {
case strings.HasSuffix(path, "/items") && r.Method == "GET":
log.Printf("Handling GET items")
handleGetItems(w, r)
case strings.HasSuffix(path, "/items") && r.Method == "POST":
log.Printf("Handling POST items")
handleAddItem(w, r)
case strings.Contains(path, "/items/") && strings.HasSuffix(path, "/lock") && r.Method == "POST":
log.Printf("Handling lock item")
handleLockItem(w, r)
case strings.Contains(path, "/items/") && r.Method == "PATCH":
log.Printf("Handling PATCH item")
handleUpdateItem(w, r)
case strings.Contains(path, "/items/") && r.Method == "DELETE":
log.Printf("Handling DELETE item")
handleDeleteItem(w, r)
case strings.HasSuffix(path, "/sse") && r.Method == "GET":
log.Printf("Handling SSE")
handleSSE(w, r)
default:
log.Printf("No handler found for %s %s", r.Method, path)
http.NotFound(w, r)
}
})
// Serve static files from embedded filesystem (register last)
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
// Check if this is a UUID path (starts with / followed by 36 characters)
isUUIDPath := len(r.URL.Path) == 37 && r.URL.Path[0] == '/' &&
!strings.Contains(r.URL.Path[1:], "/")
if r.URL.Path == "/" || isUUIDPath {
// Serve index.html at root or for routes with /{uuid}
content, err := staticFiles.ReadFile("frontend/dist/index.html")
if err != nil {
http.Error(w, "Not found", 404)
return
}
w.Header().Set("Content-Type", "text/html")
w.Write(content)
} else {
// Serve other static files from the static/ subdirectory
subFS, err := fs.Sub(staticFiles, "frontend/dist")
if err != nil {
http.Error(w, "Not found", 404)
return
}
http.StripPrefix("/", http.FileServer(http.FS(subFS))).ServeHTTP(w, r)
}
})
port := strings.TrimSpace(os.Getenv("PORT"))
if port == "" {
port = "8080"
}
parsedPort, err := strconv.Atoi(port)
if err != nil {
log.Fatalf("Invalid PORT environment variable: %v", err)
}
log.Printf("Listening on :%d", parsedPort)
log.Printf("Frontend available at: http://localhost:%d", parsedPort)
log.Fatal(http.ListenAndServe(":"+port, nil))
}