Initial commit

internal/glance/cli.go

@@ -0,0 +1,42 @@
+package glance
+
+import (
+	"flag"
+	"os"
+)
+
+type CliIntent uint8
+
+const (
+	CliIntentServe       CliIntent = iota
+	CliIntentCheckConfig           = iota
+)
+
+type CliOptions struct {
+	Intent     CliIntent
+	ConfigPath string
+}
+
+func ParseCliOptions() (*CliOptions, error) {
+	flags := flag.NewFlagSet("", flag.ExitOnError)
+
+	checkConfig := flags.Bool("check-config", false, "Check whether the config is valid")
+	configPath := flags.String("config", "glance.yml", "Set config path")
+
+	err := flags.Parse(os.Args[1:])
+
+	if err != nil {
+		return nil, err
+	}
+
+	intent := CliIntentServe
+
+	if *checkConfig {
+		intent = CliIntentCheckConfig
+	}
+
+	return &CliOptions{
+		Intent:     intent,
+		ConfigPath: *configPath,
+	}, nil
+}

internal/glance/config.go

@@ -0,0 +1,79 @@
+package glance
+
+import (
+	"fmt"
+	"io"
+
+	"gopkg.in/yaml.v3"
+)
+
+type Config struct {
+	Server Server `yaml:"server"`
+	Theme  Theme  `yaml:"theme"`
+	Pages  []Page `yaml:"pages"`
+}
+
+func NewConfigFromYml(contents io.Reader) (*Config, error) {
+	config := NewConfig()
+
+	contentBytes, err := io.ReadAll(contents)
+
+	if err != nil {
+		return nil, err
+	}
+
+	err = yaml.Unmarshal(contentBytes, config)
+
+	if err != nil {
+		return nil, err
+	}
+
+	if err = configIsValid(config); err != nil {
+		return nil, err
+	}
+
+	return config, nil
+}
+
+func NewConfig() *Config {
+	config := &Config{}
+
+	config.Server.Host = ""
+	config.Server.Port = 8080
+
+	return config
+}
+
+func configIsValid(config *Config) error {
+	for i := range config.Pages {
+		if config.Pages[i].Title == "" {
+			return fmt.Errorf("Page %d has no title", i+1)
+		}
+
+		if len(config.Pages[i].Columns) == 0 {
+			return fmt.Errorf("Page %d has no columns", i+1)
+		}
+
+		if len(config.Pages[i].Columns) > 3 {
+			return fmt.Errorf("Page %d has more than 3 columns: %d", i+1, len(config.Pages[i].Columns))
+		}
+
+		columnSizesCount := make(map[string]int)
+
+		for j := range config.Pages[i].Columns {
+			if config.Pages[i].Columns[j].Size != "small" && config.Pages[i].Columns[j].Size != "full" {
+				return fmt.Errorf("Column %d of page %d: size can only be either small or full", j+1, i+1)
+			}
+
+			columnSizesCount[config.Pages[i].Columns[j].Size]++
+		}
+
+		full := columnSizesCount["full"]
+
+		if full > 2 || full == 0 {
+			return fmt.Errorf("Page %d must have either 1 or 2 full width columns", i+1)
+		}
+	}
+
+	return nil
+}

internal/glance/glance.go

@@ -0,0 +1,221 @@
+package glance
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"log/slog"
+	"net/http"
+	"path/filepath"
+	"regexp"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/glanceapp/glance/internal/assets"
+	"github.com/glanceapp/glance/internal/widget"
+)
+
+var buildVersion = "dev"
+
+var sequentialWhitespacePattern = regexp.MustCompile(`\s+`)
+
+type Application struct {
+	Version    string
+	Config     Config
+	slugToPage map[string]*Page
+}
+
+type Theme struct {
+	BackgroundColor          *widget.HSLColorField `yaml:"background-color"`
+	PrimaryColor             *widget.HSLColorField `yaml:"primary-color"`
+	PositiveColor            *widget.HSLColorField `yaml:"positive-color"`
+	NegativeColor            *widget.HSLColorField `yaml:"negative-color"`
+	Light                    bool                  `yaml:"light"`
+	ContrastMultiplier       float32               `yaml:"contrast-multiplier"`
+	TextSaturationMultiplier float32               `yaml:"text-saturation-multiplier"`
+}
+
+type Server struct {
+	Host       string    `yaml:"host"`
+	Port       uint16    `yaml:"port"`
+	AssetsPath string    `yaml:"assets-path"`
+	StartedAt  time.Time `yaml:"-"`
+}
+
+type Column struct {
+	Size    string         `yaml:"size"`
+	Widgets widget.Widgets `yaml:"widgets"`
+}
+
+type templateData struct {
+	App  *Application
+	Page *Page
+}
+
+type Page struct {
+	Title   string   `yaml:"name"`
+	Slug    string   `yaml:"slug"`
+	Columns []Column `yaml:"columns"`
+	mu      sync.Mutex
+}
+
+func (p *Page) UpdateOutdatedWidgets() {
+	now := time.Now()
+
+	var wg sync.WaitGroup
+	context := context.Background()
+
+	for c := range p.Columns {
+		for w := range p.Columns[c].Widgets {
+			widget := p.Columns[c].Widgets[w]
+
+			if !widget.RequiresUpdate(&now) {
+				continue
+			}
+
+			wg.Add(1)
+			go func() {
+				defer wg.Done()
+				widget.Update(context)
+			}()
+		}
+	}
+
+	wg.Wait()
+}
+
+// TODO: fix, currently very simple, lots of uncovered edge cases
+func titleToSlug(s string) string {
+	s = strings.ToLower(s)
+	s = sequentialWhitespacePattern.ReplaceAllString(s, "-")
+	s = strings.Trim(s, "-")
+
+	return s
+}
+
+func NewApplication(config *Config) (*Application, error) {
+	if len(config.Pages) == 0 {
+		return nil, fmt.Errorf("no pages configured")
+	}
+
+	app := &Application{
+		Version:    buildVersion,
+		Config:     *config,
+		slugToPage: make(map[string]*Page),
+	}
+
+	app.slugToPage[""] = &config.Pages[0]
+
+	for i := range config.Pages {
+		if config.Pages[i].Slug == "" {
+			config.Pages[i].Slug = titleToSlug(config.Pages[i].Title)
+		}
+
+		app.slugToPage[config.Pages[i].Slug] = &config.Pages[i]
+	}
+
+	return app, nil
+}
+
+func (a *Application) HandlePageRequest(w http.ResponseWriter, r *http.Request) {
+	page, exists := a.slugToPage[r.PathValue("page")]
+
+	if !exists {
+		a.HandleNotFound(w, r)
+		return
+	}
+
+	pageData := templateData{
+		Page: page,
+		App:  a,
+	}
+
+	var responseBytes bytes.Buffer
+	err := assets.PageTemplate.Execute(&responseBytes, pageData)
+
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		w.Write([]byte(err.Error()))
+		return
+	}
+
+	w.Write(responseBytes.Bytes())
+}
+
+func (a *Application) HandlePageContentRequest(w http.ResponseWriter, r *http.Request) {
+	page, exists := a.slugToPage[r.PathValue("page")]
+
+	if !exists {
+		a.HandleNotFound(w, r)
+		return
+	}
+
+	pageData := templateData{
+		Page: page,
+	}
+
+	page.mu.Lock()
+	defer page.mu.Unlock()
+	page.UpdateOutdatedWidgets()
+
+	var responseBytes bytes.Buffer
+	err := assets.PageContentTemplate.Execute(&responseBytes, pageData)
+
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		w.Write([]byte(err.Error()))
+		return
+	}
+
+	w.Write(responseBytes.Bytes())
+}
+
+func (a *Application) HandleNotFound(w http.ResponseWriter, r *http.Request) {
+	// TODO: add proper not found page
+	w.WriteHeader(http.StatusNotFound)
+	w.Write([]byte("Page not found"))
+}
+
+func FileServerWithCache(fs http.FileSystem, cacheDuration time.Duration) http.Handler {
+	server := http.FileServer(fs)
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// TODO: fix always setting cache control even if the file doesn't exist
+		w.Header().Set("Cache-Control", fmt.Sprintf("public, max-age=%d", int(cacheDuration.Seconds())))
+		server.ServeHTTP(w, r)
+	})
+}
+
+func (a *Application) Serve() error {
+	// TODO: add gzip support, static files must have their gzipped contents cached
+	// TODO: add HTTPS support
+	mux := http.NewServeMux()
+
+	mux.HandleFunc("GET /{$}", a.HandlePageRequest)
+	mux.HandleFunc("GET /{page}", a.HandlePageRequest)
+	mux.HandleFunc("GET /api/pages/{page}/content/{$}", a.HandlePageContentRequest)
+	mux.Handle("GET /static/{path...}", http.StripPrefix("/static/", FileServerWithCache(http.FS(assets.PublicFS), 2*time.Hour)))
+
+	if a.Config.Server.AssetsPath != "" {
+		absAssetsPath, err := filepath.Abs(a.Config.Server.AssetsPath)
+
+		if err != nil {
+			return fmt.Errorf("invalid assets path: %s", a.Config.Server.AssetsPath)
+		}
+
+		slog.Info("Serving assets", "path", absAssetsPath)
+		assetsFS := FileServerWithCache(http.Dir(a.Config.Server.AssetsPath), 2*time.Hour)
+		mux.Handle("/assets/{path...}", http.StripPrefix("/assets/", assetsFS))
+	}
+
+	server := http.Server{
+		Addr:    fmt.Sprintf("%s:%d", a.Config.Server.Host, a.Config.Server.Port),
+		Handler: mux,
+	}
+
+	a.Config.Server.StartedAt = time.Now()
+
+	slog.Info("Starting server", "host", a.Config.Server.Host, "port", a.Config.Server.Port)
+	return server.ListenAndServe()
+}

internal/glance/main.go

@@ -0,0 +1,46 @@
+package glance
+
+import (
+	"fmt"
+	"os"
+)
+
+func Main() int {
+	options, err := ParseCliOptions()
+
+	if err != nil {
+		fmt.Println(err)
+		return 1
+	}
+
+	configFile, err := os.Open(options.ConfigPath)
+
+	if err != nil {
+		fmt.Printf("failed opening config file: %v\n", err)
+		return 1
+	}
+
+	config, err := NewConfigFromYml(configFile)
+	configFile.Close()
+
+	if err != nil {
+		fmt.Printf("failed parsing config file: %v\n", err)
+		return 1
+	}
+
+	if options.Intent == CliIntentServe {
+		app, err := NewApplication(config)
+
+		if err != nil {
+			fmt.Printf("failed creating application: %v\n", err)
+			return 1
+		}
+
+		if app.Serve() != nil {
+			fmt.Printf("http server error: %v\n", err)
+			return 1
+		}
+	}
+
+	return 0
+}