1 files changed, 125 insertions, 0 deletions
diff --git a/app/app.go b/app/app.go
new file mode 100644
index 0000000..1ea0ee8
--- /dev/null
+++ b/app/app.go
@@ -0,0 +1,125 @@
+package app
+
+import (
+	"bytes"
+	"context"
+	"os"
+	"text/template"
+	"time"
+
+	tgbotapi "github.com/go-telegram-bot-api/telegram-bot-api/v5"
+	"github.com/mmcdole/gofeed"
+	"gitrepo.ru/neonxp/rss2world/templates"
+)
+
+type App struct {
+	config    *Config
+	telegram  *tgbotapi.BotAPI
+	templates *template.Template
+}
+
+func New(cfg *Config) (*App, error) {
+	bot, err := tgbotapi.NewBotAPI(cfg.Telegram.BotToken)
+	if err != nil {
+		return nil, err
+	}
+
+	tpl, err := template.ParseFS(templates.Templates, "*.gotmpl")
+	if err != nil {
+		return nil, err
+	}
+
+	return &App{
+		config:    cfg,
+		telegram:  bot,
+		templates: tpl,
+	}, nil
+}
+
+func (a *App) Run(ctx context.Context) error {
+	ticker := time.NewTicker(a.config.RSS.CheckInterval)
+	for {
+		select {
+		case <-ctx.Done():
+			return nil
+		case <-ticker.C:
+			if err := a.iteration(); err != nil {
+				return err
+			}
+		}
+	}
+}
+
+func (a *App) iteration() error {
+
+	seq, err := a.readSeqFile()
+	if os.IsNotExist(err) {
+		seq = ""
+		err = nil
+	}
+	if err != nil {
+		return err
+	}
+
+	items, err := a.findNewItems(seq)
+	if err != nil || len(items) == 0 {
+		return err
+	}
+
+	for i := len(items) - 1; i >= 0; i-- {
+		if err := a.processItem(items[i]); err != nil {
+			return err
+		}
+		if err := a.writeSeqFile(items[i].GUID); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (a *App) processItem(item *gofeed.Item) error {
+	buf := bytes.NewBufferString("")
+	if err := a.templates.ExecuteTemplate(buf, "telegram", item); err != nil {
+		return err
+	}
+	for _, group := range a.config.Telegram.TargetGroups {
+		msg := tgbotapi.NewMessage(group, buf.String())
+		msg.ParseMode = tgbotapi.ModeHTML
+		if _, err := a.telegram.Send(msg); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (a *App) readSeqFile() (string, error) {
+	seqVal, err := os.ReadFile(a.config.RSS.SeqFile)
+	if err != nil {
+		return "", err
+	}
+
+	return string(seqVal), nil
+}
+
+func (a *App) writeSeqFile(seqVal string) error {
+	return os.WriteFile(a.config.RSS.SeqFile, []byte(seqVal), 0644)
+}
+
+func (a *App) findNewItems(from string) ([]*gofeed.Item, error) {
+	fp := gofeed.NewParser()
+	feed, err := fp.ParseURL(a.config.RSS.URL)
+	if err != nil {
+		return nil, err
+	}
+	out := make([]*gofeed.Item, 0, len(feed.Items))
+	for _, item := range feed.Items {
+		if item.GUID == from {
+			break
+		}
+		out = append(out, item)
+	}
+
+	return out, nil
+}