feat: send new blog posts to subscribers

5 files changed, 176 insertions, 8 deletions

diff --git a/internal/b2/client.go b/internal/b2/client.go
index 7b745a8..d712736 100644
--- a/internal/b2/client.go
+++ b/internal/b2/client.go
@@ -3,6 +3,7 @@ package b2
 import (
 	"context"
 	"fmt"
+	"slices"
 	"strings"
 	"time"
 
@@ -34,6 +35,7 @@ func NewB2Client(cfg *config.B2Config) (*B2Client, error) {
 type BlogPage struct {
 	Link     string
 	FileName string
+	Lang     string
 	Metadata *frontmatter.Metadata
 }
 
@@ -74,6 +76,9 @@ func (c *B2Client) Scan(prefix string) ([]*BlogPage, error) {
 		nameParts := strings.Split(linkParts[len(linkParts)-1], ".")
 		fileName := strings.Join(nameParts[:len(linkParts)-1], ".")
 
+		tags := strings.Split(attrs.Info["tags"], ",")
+		slices.Sort(tags)
+
 		filePaths = append(filePaths, &BlogPage{
 			Link:     obj.Name(),
 			FileName: fileName,
@@ -83,7 +88,7 @@ func (c *B2Client) Scan(prefix string) ([]*BlogPage, error) {
 				ActionDate:       attrs.Info["action-date"],
 				PublishedTime:    publishedTime,
 				Thumbnail:        attrs.Info["thumbnail"],
-				Tags:             strings.Split(attrs.Info["tags"], ","),
+				Tags:             tags,
 				Geolocation:      attrs.Info["geolocation"],
 			},
 		})
diff --git a/internal/blogtrigger/blogtrigger.go b/internal/blogtrigger/blogtrigger.go
new file mode 100644
index 0000000..ab66981
--- /dev/null
+++ b/internal/blogtrigger/blogtrigger.go
@@ -0,0 +1,68 @@
+package blogtrigger
+
+import (
+	"fmt"
+	"log/slog"
+
+	"github.com/SayaAndy/saya-today-web/config"
+	"github.com/SayaAndy/saya-today-web/internal/b2"
+	"github.com/go-co-op/gocron/v2"
+)
+
+type BlogTriggerScheduler struct {
+	s              gocron.Scheduler
+	knownBlogPages map[string]map[string]*b2.BlogPage
+	b2Client       *b2.B2Client
+	onTrigger      func([]*b2.BlogPage) error
+}
+
+func NewBlogTriggerScheduler(b2Client *b2.B2Client, availableLanguages []config.AvailableLanguageConfig, onTrigger func([]*b2.BlogPage) error) (*BlogTriggerScheduler, error) {
+	s, err := gocron.NewScheduler()
+	if err != nil {
+		return nil, fmt.Errorf("failed to create new scheduler: %w", err)
+	}
+
+	knownBlogPages := make(map[string]map[string]*b2.BlogPage, len(availableLanguages))
+	for _, lang := range availableLanguages {
+		knownBlogPages[lang.Name] = make(map[string]*b2.BlogPage)
+	}
+
+	bts := &BlogTriggerScheduler{s, knownBlogPages, b2Client, onTrigger}
+	defer bts.s.Start()
+
+	bts.s.NewJob(gocron.CronJob("0/5 * * * *", false), gocron.NewTask(func(bts *BlogTriggerScheduler) {
+		posts, err := bts.scan()
+		if err != nil {
+			slog.Error("failed to execute scanning new blog pages cron job", slog.String("error", err.Error()))
+			return
+		}
+		if err = onTrigger(posts); err != nil {
+			slog.Error("error happened on callback function after scanning new blog pages", slog.String("error", err.Error()))
+			return
+		}
+	}, bts))
+
+	if _, err = bts.scan(); err != nil {
+		return nil, fmt.Errorf("failed to scan existing blog pages in b2: %w", err)
+	}
+
+	return bts, nil
+}
+
+func (bts *BlogTriggerScheduler) scan() (newPages []*b2.BlogPage, err error) {
+	newPages = make([]*b2.BlogPage, 0)
+	for lang := range bts.knownBlogPages {
+		posts, err := bts.b2Client.Scan(lang + "/")
+		if err != nil {
+			return nil, fmt.Errorf("failed to scan blog pages in b2 on '%s': %w", lang, err)
+		}
+		for _, post := range posts {
+			if _, ok := bts.knownBlogPages[lang][post.FileName]; !ok {
+				post.Lang = lang
+				newPages = append(newPages, post)
+				bts.knownBlogPages[lang][post.FileName] = post
+			}
+		}
+	}
+	return newPages, nil
+}
diff --git a/internal/mailer/mailer.go b/internal/mailer/mailer.go
index ba2202e..f51186e 100644
--- a/internal/mailer/mailer.go
+++ b/internal/mailer/mailer.go
@@ -7,11 +7,13 @@ import (
 	"encoding/binary"
 	"fmt"
 	"log/slog"
+	"slices"
 	"strconv"
 	"strings"
 	"sync"
 	"time"
 
+	"github.com/SayaAndy/saya-today-web/internal/b2"
 	"github.com/SayaAndy/saya-today-web/internal/templatemanager"
 	"github.com/SayaAndy/saya-today-web/locale"
 	"github.com/dgraph-io/ristretto/v2"
@@ -149,16 +151,14 @@ func (m *Mailer) MailIsTaken(email string) (bool, error) {
 	return isTaken, nil
 }
 
-func (m *Mailer) GetInfo(userId string) (email string, lang string, err error) {
-	hash := m.GetHash(userId)
-
+func (m *Mailer) GetInfo(userIdHash []byte) (email string, lang string, err error) {
 	tx, err := m.db.Begin()
 	if err != nil {
 		return "", "", fmt.Errorf("failed to initialize transaction with db: %s", err)
 	}
 
 	var rows *sql.Rows
-	if rows, err = tx.Query(`SELECT email, lang FROM user_email_table WHERE user_id=? LIMIT 1;`, hash); err != nil {
+	if rows, err = tx.Query(`SELECT email, lang FROM user_email_table WHERE user_id=? LIMIT 1;`, userIdHash); err != nil {
 		tx.Rollback()
 		return "", "", fmt.Errorf("failed to query user-email settings in db: %s", err)
 	}
@@ -330,6 +330,7 @@ func (m *Mailer) Subscribe(userId string, subscriptionType SubscriptionType, tag
 		return fmt.Errorf("failed to initialize transaction with db: %s", err)
 	}
 
+	slices.Sort(tags)
 	tagsOutput := ""
 	switch subscriptionType {
 	case All:
@@ -357,6 +358,98 @@ func (m *Mailer) Subscribe(userId string, subscriptionType SubscriptionType, tag
 	return nil
 }
 
-func SendNewPost() {
+func (m *Mailer) NewPost(post *b2.BlogPage) error {
+	tx, err := m.db.Begin()
+	if err != nil {
+		return fmt.Errorf("failed to initialize transaction with db: %s", err)
+	}
+
+	var rows *sql.Rows
+	if rows, err = tx.Query(`SELECT user_id, tags FROM subscription_user_to_tags_table;`); err != nil {
+		tx.Rollback()
+		return fmt.Errorf("failed to query user-to-tags table in db: %s", err)
+	}
+
+	var userId []byte
+	usersToSend := make([]string, 0)
+	var tagsString string
+	i := -1
+
+rowLoop:
+	for rows.Next() {
+		i++
+		if err = rows.Scan(&userId, &tagsString); err != nil {
+			slog.Warn("failed to scan a row in user-to-tags table", slog.String("error", err.Error()), slog.Int("index", i), slog.String("user_id", base64.RawStdEncoding.EncodeToString(userId)))
+			continue
+		}
+
+		if tagsString == "" {
+			continue
+		}
+
+		email, lang, err := m.GetInfo(userId)
+		if err != nil {
+			slog.Warn("failed to get info about the user", slog.String("error", err.Error()), slog.Int("index", i), slog.String("user_id", base64.RawStdEncoding.EncodeToString(userId)))
+			continue
+		}
 
+		if lang != post.Lang {
+			continue
+		}
+
+		if tagsString == "_all" {
+			usersToSend = append(usersToSend, email)
+			continue
+		}
+
+		pageTags := strings.Split(tagsString, ",")
+		for _, tag := range pageTags {
+			if _, found := slices.BinarySearch(post.Metadata.Tags, tag); found {
+				usersToSend = append(usersToSend, email)
+				continue rowLoop
+			}
+		}
+	}
+
+	tx.Commit()
+	rows.Close()
+
+	msgBody, err := m.tm.Render("new-post", fiber.Map{
+		"L":          m.l[post.Lang],
+		"Lang":       post.Lang,
+		"Post":       post,
+		"ClientHost": m.clientHost,
+	})
+
+	messages := make([]*mail.Msg, 0, len(usersToSend))
+	for _, user := range usersToSend {
+		if err != nil {
+			return fmt.Errorf("failed to render message body: %w", err)
+		}
+
+		message := mail.NewMsg()
+
+		if err := message.EnvelopeFrom(m.mailAddress); err != nil {
+			return fmt.Errorf("failed to set ENVELOPE FROM address: %w", err)
+		}
+		if err := message.FromFormat(m.publicName, m.mailAddress); err != nil {
+			return fmt.Errorf("failed to set formatted FROM address: %w", err)
+		}
+		if err := message.To(user); err != nil {
+			return fmt.Errorf("failed to set TO address: %w", err)
+		}
+
+		message.SetMessageID()
+		message.SetDate()
+		message.SetBulk()
+		message.Subject(m.l[post.Lang].Mail.NewPost.Subject)
+		message.SetBodyString(mail.TypeTextHTML, string(msgBody))
+
+		messages = append(messages, message)
+	}
+
+	if err := m.mailClient.DialAndSend(messages...); err != nil {
+		return fmt.Errorf("failed to send new post notifications: %w", err)
+	}
+	return nil
 }
diff --git a/internal/router/api-v1-email-send-verification-code.go b/internal/router/api-v1-email-send-verification-code.go
index 2cde1bd..9372eb3 100644
--- a/internal/router/api-v1-email-send-verification-code.go
+++ b/internal/router/api-v1-email-send-verification-code.go
@@ -58,7 +58,7 @@ func Api_V1_Email_SendVerificationCode(l map[string]*locale.LocaleConfig) func(c
 			})
 		}
 
-		if previousEmail, _, _ := Mailer.GetInfo(id); previousEmail == email {
+		if previousEmail, _, _ := Mailer.GetInfo(Mailer.GetHash(id)); previousEmail == email {
 			return api_v1_email_sendStatusHtml(c, "email-message", l, "Failed", fiber.ErrUnprocessableEntity.Code, lang, l[lang].UserProfile.EmailAlreadyValidated, map[string]string{})
 		}
 
diff --git a/internal/router/api-v1-general-page-body.go b/internal/router/api-v1-general-page-body.go
index 66f1234..b5567b7 100644
--- a/internal/router/api-v1-general-page-body.go
+++ b/internal/router/api-v1-general-page-body.go
@@ -14,6 +14,7 @@ import (
 
 	"github.com/SayaAndy/saya-today-web/config"
 	"github.com/SayaAndy/saya-today-web/internal/b2"
+	"github.com/SayaAndy/saya-today-web/internal/blogtrigger"
 	"github.com/SayaAndy/saya-today-web/internal/factgiver"
 	"github.com/SayaAndy/saya-today-web/internal/frontmatter"
 	"github.com/SayaAndy/saya-today-web/internal/mailer"
@@ -24,6 +25,7 @@ import (
 
 var FactGiver *factgiver.FactGiver
 var Mailer *mailer.Mailer
+var BlogTrigger *blogtrigger.BlogTriggerScheduler
 
 func init() {
 	assert(0, tm.Add("general-page-body", "views/partials/general-page-body.html"))
@@ -110,7 +112,7 @@ func Api_V1_GeneralPage_Body(l map[string]*locale.LocaleConfig, langs []config.A
 		} else if len(pathParts) == 2 && pathParts[1] == "user" {
 			values["Title"] = l[lang].UserProfile.Header
 
-			email, _, err := Mailer.GetInfo(c.IP())
+			email, _, err := Mailer.GetInfo(Mailer.GetHash(c.IP()))
 			if err != nil {
 				slog.Error("get info from mailer about a client", slog.String("error", err.Error()))
 			}