feat: email linking

17 files changed, 545 insertions, 225 deletions

diff --git a/internal/mailer/mailer.go b/internal/mailer/mailer.go
new file mode 100644
index 0000000..450b818
--- /dev/null
+++ b/internal/mailer/mailer.go
@@ -0,0 +1,281 @@
+package mailer
+
+import (
+	"crypto/rand"
+	"database/sql"
+	"encoding/base64"
+	"encoding/binary"
+	"fmt"
+	"log/slog"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/SayaAndy/saya-today-web/internal/templatemanager"
+	"github.com/SayaAndy/saya-today-web/locale"
+	"github.com/dgraph-io/ristretto/v2"
+	"github.com/gofiber/fiber/v2"
+	"github.com/wneessen/go-mail"
+	"golang.org/x/crypto/argon2"
+)
+
+type Mailer struct {
+	verificationCodes *ristretto.Cache[uint64, string]
+	db                *sql.DB
+	tm                *templatemanager.TemplateManager
+	mailClient        *mail.Client
+	clientHost        string
+	mailAddress       string
+	publicName        string
+	salt              []byte
+
+	lostMailMap map[string]struct {
+		Dur        time.Duration
+		End        time.Time
+		CodeExpiry time.Time
+	}
+	lostMailMapMutex sync.RWMutex
+
+	hashMap      map[string][]byte
+	hashMapMutex sync.RWMutex
+
+	l map[string]*locale.LocaleConfig
+}
+
+func NewMailer(db *sql.DB, clientHost string, mailHost string, publicName string, mailAddress string, username string, password string, salt []byte, localization map[string]*locale.LocaleConfig) (*Mailer, error) {
+	verificationCodes, err := ristretto.NewCache(&ristretto.Config[uint64, string]{
+		NumCounters:            10000,
+		MaxCost:                1 << 20, // 1 MB
+		BufferItems:            64,
+		TtlTickerDurationInSec: 3600,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("fail to initialize cache for verification codes: %w", err)
+	}
+
+	tm, err := templatemanager.NewTemplateManager(templatemanager.TemplateManagerTemplates{
+		Name:  "new-post",
+		Files: []string{"views/layouts/general-mail.html", "views/messages/new-post.html"},
+	}, templatemanager.TemplateManagerTemplates{
+		Name:  "verify-email",
+		Files: []string{"views/layouts/general-mail.html", "views/messages/verify-email.html"},
+	})
+	if err != nil {
+		return nil, fmt.Errorf("fail to initialize template manager for message templating: %w", err)
+	}
+
+	mailClient, err := mail.NewClient(mailHost,
+		mail.WithSMTPAuth(mail.SMTPAuthAutoDiscover), mail.WithTLSPortPolicy(mail.TLSMandatory),
+		mail.WithUsername(username), mail.WithPassword(password),
+	)
+	if err != nil {
+		return nil, fmt.Errorf("fail to initialize mail client: %w", err)
+	}
+
+	return &Mailer{
+		verificationCodes: verificationCodes,
+		db:                db,
+		clientHost:        clientHost,
+		tm:                tm,
+		mailClient:        mailClient,
+		mailAddress:       mailAddress,
+		publicName:        publicName,
+		salt:              salt,
+		hashMap:           make(map[string][]byte),
+		lostMailMap: make(map[string]struct {
+			Dur        time.Duration
+			End        time.Time
+			CodeExpiry time.Time
+		}, 0),
+		l: localization}, nil
+}
+
+func (m *Mailer) GetHash(id string) []byte {
+	m.hashMapMutex.RLock()
+	if val, ok := m.hashMap[id]; ok {
+		m.hashMapMutex.RUnlock()
+		slog.Debug("gave an old hash", slog.String("hash", base64.RawStdEncoding.EncodeToString(val)))
+		return val
+	}
+	m.hashMapMutex.RUnlock()
+
+	m.hashMapMutex.Lock()
+	defer m.hashMapMutex.Unlock()
+
+	if val, ok := m.hashMap[id]; ok {
+		slog.Debug("gave a newly generated hash", slog.String("hash", base64.RawStdEncoding.EncodeToString(val)))
+		return val
+	}
+
+	m.hashMap[id] = argon2.IDKey([]byte(id), m.salt, 1, 64*1024, 4, 32)
+	slog.Debug("generated hash", slog.String("hash", base64.RawStdEncoding.EncodeToString(m.hashMap[id])))
+	return m.hashMap[id]
+}
+
+func (m *Mailer) IsAllowedToRetryVerification(userId string) (retryAllowed bool, whenAllowed time.Time, codeExpiry time.Time) {
+	m.lostMailMapMutex.RLock()
+	defer m.lostMailMapMutex.RUnlock()
+	previous, ok := m.lostMailMap[userId]
+	if ok && previous.End.After(time.Now()) {
+		return false, previous.End, previous.CodeExpiry
+	}
+	return true, time.Time{}, previous.CodeExpiry
+}
+
+func (m *Mailer) MailIsTaken(email string) (bool, error) {
+	tx, err := m.db.Begin()
+	if err != nil {
+		return false, fmt.Errorf("failed to initialize transaction with db: %s", err)
+	}
+
+	var rows *sql.Rows
+	if rows, err = tx.Query(`SELECT email FROM user_email_table WHERE email=? LIMIT 1;`, email); err != nil {
+		tx.Rollback()
+		return false, fmt.Errorf("failed to query user-email settings in db: %s", err)
+	}
+	defer tx.Commit()
+	defer rows.Close()
+
+	return rows.Next(), nil
+}
+
+func (m *Mailer) GetInfo(userId string) (email string, lang string, err error) {
+	hash := m.GetHash(userId)
+
+	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 {
+		tx.Rollback()
+		return "", "", fmt.Errorf("failed to query user-email settings in db: %s", err)
+	}
+	defer tx.Commit()
+	defer rows.Close()
+
+	if !rows.Next() {
+		return "", "", nil
+	}
+
+	if err = rows.Scan(&email, &lang); err != nil {
+		return "", "", fmt.Errorf("failed to scan the result from user-email settings query: %s", err)
+	}
+	return
+}
+
+func (m *Mailer) SendVerificationCode(userId string, address string, lang string) error {
+	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(address); err != nil {
+		return fmt.Errorf("failed to set TO address: %w", err)
+	}
+
+	message.SetMessageID()
+	message.SetDate()
+	message.SetBulk()
+
+	dur := 1 * time.Minute
+	m.lostMailMapMutex.Lock()
+	if previous, ok := m.lostMailMap[userId]; ok {
+		if time.Now().Before(previous.End) {
+			m.lostMailMapMutex.Unlock()
+			return fmt.Errorf("user is not allowed to send another verification code until %s", previous.End)
+		}
+		dur = 2 * m.lostMailMap[userId].Dur
+	}
+	m.lostMailMap[userId] = struct {
+		Dur        time.Duration
+		End        time.Time
+		CodeExpiry time.Time
+	}{Dur: dur, End: time.Now().Add(dur), CodeExpiry: time.Now().Add(time.Hour)}
+	m.lostMailMapMutex.Unlock()
+
+	verificationCodeBytes := make([]byte, 8)
+	rand.Read(verificationCodeBytes)
+	verificationCode := binary.LittleEndian.Uint64(verificationCodeBytes)
+
+	verificationInfo := fmt.Sprintf("%s.%s", base64.RawStdEncoding.EncodeToString([]byte(userId)), base64.RawStdEncoding.EncodeToString([]byte(address)))
+	m.verificationCodes.Set(verificationCode, verificationInfo, int64(len(verificationInfo)+8))
+
+	message.Subject(m.l[lang].Mail.VerifyEmail.Subject)
+
+	msg, err := m.tm.Render("verify-email", fiber.Map{
+		"L":                m.l[lang],
+		"Lang":             lang,
+		"VerificationCode": fmt.Sprintf("%X", verificationCode),
+		"ClientHost":       m.clientHost,
+	})
+	if err != nil {
+		return fmt.Errorf("failed to render message body: %w", err)
+	}
+
+	message.SetBodyString(mail.TypeTextHTML, string(msg))
+	if err := m.mailClient.DialAndSend(message); err != nil {
+		return fmt.Errorf("failed to send verification code message: %w", err)
+	}
+	slog.Debug("verification code message successfully delivered", slog.String("address", address), slog.String("user_id", userId))
+	return nil
+}
+
+func (m *Mailer) Verify(verificationCodeEncoded string, lang string) error {
+	verificationCode, err := strconv.ParseUint(verificationCodeEncoded, 16, 64)
+	if err != nil {
+		return fmt.Errorf("failed to decode verification code from 8-byte hex: %w", err)
+	}
+
+	verificationInfo, _ := m.verificationCodes.Get(verificationCode)
+	if verificationInfo == "" {
+		return fmt.Errorf("failed to get verification info by its code (might be absent, might be empty)")
+	}
+
+	verificationSegments := strings.Split(verificationInfo, ".")
+	if len(verificationSegments) != 2 {
+		m.verificationCodes.Del(verificationCode)
+		return fmt.Errorf("invalid format of verification info: expected %d segments, got %d", 2, len(verificationSegments))
+	}
+
+	userId, err := base64.RawStdEncoding.DecodeString(verificationSegments[0])
+	if err != nil {
+		m.verificationCodes.Del(verificationCode)
+		delete(m.lostMailMap, verificationSegments[0])
+		return fmt.Errorf("could not decode user id: %s", err)
+	}
+
+	address, err := base64.RawStdEncoding.DecodeString(verificationSegments[1])
+	if err != nil {
+		m.verificationCodes.Del(verificationCode)
+		delete(m.lostMailMap, verificationSegments[0])
+		return fmt.Errorf("could not decode address: %s", err)
+	}
+
+	tx, err := m.db.Begin()
+	if err != nil {
+		return fmt.Errorf("failed to initialize transaction with db: %s", err)
+	}
+
+	if _, err = tx.Exec(`INSERT INTO user_email_table(user_id, email, lang) VALUES(?, ?, ?)
+  ON CONFLICT(user_id) DO UPDATE SET
+  	email=excluded.email,
+	lang=excluded.lang;`, m.GetHash(string(userId)), address, lang); err != nil {
+		tx.Rollback()
+		return fmt.Errorf("failed to configure user-email settings in db: %s", err)
+	}
+
+	if err = tx.Commit(); err != nil {
+		tx.Rollback()
+		return fmt.Errorf("failed to commit transaction to db: %s", err)
+	}
+
+	m.verificationCodes.Del(verificationCode)
+	delete(m.lostMailMap, verificationSegments[0])
+	return nil
+}
diff --git a/internal/router/api-v1-blog-search.go b/internal/router/api-v1-blog-search.go
index ab5425c..5b1d14d 100644
--- a/internal/router/api-v1-blog-search.go
+++ b/internal/router/api-v1-blog-search.go
@@ -17,7 +17,7 @@ import (
 )
 
 func init() {
-	tm.Add("catalogue-blog-cards", "views/partials/catalogue-blog-cards.html", "views/partials/catalogue-blog-card-tags.html")
+	assert(0, tm.Add("catalogue-blog-cards", "views/partials/catalogue-blog-cards.html", "views/partials/catalogue-blog-card-tags.html"))
 }
 
 func Api_V1_BlogSearch(l map[string]*locale.LocaleConfig, langs []config.AvailableLanguageConfig, b2Client *b2.B2Client) func(c *fiber.Ctx) error {
diff --git a/internal/router/api-v1-email-is-in-verification.go b/internal/router/api-v1-email-is-in-verification.go
new file mode 100644
index 0000000..83c783c
--- /dev/null
+++ b/internal/router/api-v1-email-is-in-verification.go
@@ -0,0 +1,58 @@
+package router
+
+import (
+	"fmt"
+	"net/url"
+	"strings"
+
+	"github.com/SayaAndy/saya-today-web/locale"
+	"github.com/gofiber/fiber/v2"
+)
+
+func init() {
+	assert(0, tm.Add("personal-page-status", "views/partials/personal-page-status.html"))
+}
+
+func Api_V1_Email_IsInVerification(l map[string]*locale.LocaleConfig) func(c *fiber.Ctx) error {
+	return func(c *fiber.Ctx) error {
+		c.Set(fiber.HeaderContentType, fiber.MIMETextPlainCharsetUTF8)
+
+		id := c.IP()
+		lang := "en"
+
+		var referer, path string
+		var pathParts []string
+		var urlStruct *url.URL
+		var err error
+
+		referer = c.Get("Referer", "")
+		if referer == "" {
+			goto skipFetchingLang
+		}
+
+		urlStruct, err = url.ParseRequestURI(referer)
+		if err != nil {
+			goto skipFetchingLang
+		}
+
+		path = urlStruct.EscapedPath()
+		pathParts = strings.Split(strings.Trim(path, "/"), "/")
+		if len(pathParts) == 0 {
+			goto skipFetchingLang
+		}
+
+		lang = pathParts[0]
+
+	skipFetchingLang:
+		isAllowed, whenAllowed, codeExpiry := Mailer.IsAllowedToRetryVerification(id)
+		if !isAllowed {
+			return api_v1_email_sendStatusHtml(c, "email-message", l, "Neutral", fiber.StatusOK, lang, strings.ReplaceAll(l[lang].UserProfile.DelayTilVerification, "{}", whenAllowed.Format("2006-01-02 15:04:05 MST")), map[string]string{
+				"striked-end-time": fmt.Sprint(whenAllowed.UnixMilli()),
+				"code-expiry-time": fmt.Sprint(codeExpiry.UnixMilli()),
+			})
+		}
+		return api_v1_email_sendStatusHtml(c, "email-message", l, "OK", fiber.StatusOK, lang, "", map[string]string{
+			"code-expiry-time": fmt.Sprint(codeExpiry.UnixMilli()),
+		})
+	}
+}
diff --git a/internal/router/api-v1-email-send-verification-code.go b/internal/router/api-v1-email-send-verification-code.go
new file mode 100644
index 0000000..2cde1bd
--- /dev/null
+++ b/internal/router/api-v1-email-send-verification-code.go
@@ -0,0 +1,98 @@
+package router
+
+import (
+	"fmt"
+	"html/template"
+	"log/slog"
+	"net/url"
+	"strings"
+
+	"github.com/SayaAndy/saya-today-web/locale"
+	"github.com/gofiber/fiber/v2"
+)
+
+func init() {
+	assert(0, tm.Add("personal-page-status", "views/partials/personal-page-status.html"))
+}
+
+func Api_V1_Email_SendVerificationCode(l map[string]*locale.LocaleConfig) func(c *fiber.Ctx) error {
+	return func(c *fiber.Ctx) error {
+		c.Set(fiber.HeaderContentType, fiber.MIMETextPlainCharsetUTF8)
+
+		referer := c.Get("Referer", "")
+		if referer == "" {
+			return c.Status(fiber.ErrBadRequest.Code).SendString("'Referer' header is empty")
+		}
+
+		urlStruct, err := url.ParseRequestURI(referer)
+		if err != nil {
+			return c.Status(fiber.ErrBadRequest.Code).SendString(fmt.Sprintf("'Referer' header is invalid: %s", err.Error()))
+		}
+
+		path := urlStruct.EscapedPath()
+		pathParts := strings.Split(strings.Trim(path, "/"), "/")
+		if len(pathParts) != 2 {
+			return c.Status(fiber.ErrBadRequest.Code).SendString("'Referer' header is invalid: expect format '/{lang}/user'")
+		}
+
+		lang := pathParts[0]
+		id := c.IP()
+
+		email := c.FormValue("email")
+		if email == "" {
+			return api_v1_email_sendStatusHtml(c, "email-message", l, "Failed", fiber.ErrUnprocessableEntity.Code, lang, l[lang].UserProfile.EmailEmpty, map[string]string{})
+		}
+
+		isTaken, err := Mailer.MailIsTaken(email)
+		if err != nil {
+			slog.Error("failed to check if address is already taken", slog.String("error", err.Error()))
+			return api_v1_email_sendStatusHtml(c, "email-message", l, "Failed", fiber.ErrUnprocessableEntity.Code, lang, l[lang].UserProfile.VerificationCodeSendingError, map[string]string{})
+		}
+		if isTaken {
+			return api_v1_email_sendStatusHtml(c, "email-message", l, "Failed", fiber.ErrUnprocessableEntity.Code, lang, l[lang].UserProfile.EmailTaken, map[string]string{})
+		}
+
+		if isAllowed, whenAllowed, _ := Mailer.IsAllowedToRetryVerification(id); !isAllowed {
+			return api_v1_email_sendStatusHtml(c, "email-message", l, "Failed", fiber.ErrUnprocessableEntity.Code, lang, strings.ReplaceAll(l[lang].UserProfile.DelayTilVerification, "{}", whenAllowed.Format("2006-01-02 15:04:05 MST")), map[string]string{
+				"striked-end-time": fmt.Sprint(whenAllowed.UnixMilli()),
+			})
+		}
+
+		if previousEmail, _, _ := Mailer.GetInfo(id); previousEmail == email {
+			return api_v1_email_sendStatusHtml(c, "email-message", l, "Failed", fiber.ErrUnprocessableEntity.Code, lang, l[lang].UserProfile.EmailAlreadyValidated, map[string]string{})
+		}
+
+		if err = Mailer.SendVerificationCode(id, email, lang); err != nil {
+			slog.Error("failed to send a verification code", slog.String("error", err.Error()))
+			return api_v1_email_sendStatusHtml(c, "email-message", l, "Failed", fiber.ErrUnprocessableEntity.Code, lang, l[lang].UserProfile.VerificationCodeSendingError, map[string]string{})
+		}
+
+		_, endTime, codeExpiry := Mailer.IsAllowedToRetryVerification(id)
+		return api_v1_email_sendStatusHtml(c, "email-message", l, "OK", fiber.StatusOK, lang, strings.ReplaceAll(l[lang].UserProfile.VerificationCodeSent, "{}", endTime.Format("2006-01-02 15:04:05 MST")), map[string]string{
+			"striked-end-time": fmt.Sprint(endTime.UnixMilli()),
+			"code-expiry-time": fmt.Sprint(codeExpiry.UnixMilli()),
+		})
+	}
+}
+
+func api_v1_email_sendStatusHtml(c *fiber.Ctx, divId string, l map[string]*locale.LocaleConfig, status string, code int, lang string, message string, dataAttributes map[string]string) error {
+	sterileDataset := make(map[string]interface{})
+	for k, v := range dataAttributes {
+		sterileDataset[k] = template.HTMLAttr(fmt.Sprintf("data-%s=\"%s\"", k, template.HTMLEscapeString(v)))
+	}
+
+	content, err := tm.Render("personal-page-status", fiber.Map{
+		"L":              l[lang],
+		"Status":         status,
+		"Message":        message,
+		"StatusId":       divId,
+		"DataAttributes": sterileDataset,
+	})
+	if err != nil {
+		c.Set(fiber.HeaderContentType, fiber.MIMETextPlainCharsetUTF8)
+		slog.Error("failed to render the email status message", slog.String("error", err.Error()), slog.String("div_id", divId), slog.String("message", message))
+		return c.Status(fiber.ErrInternalServerError.Code).SendString("Failed to render the email status message, please ask administrator for a more detailed cause")
+	}
+	c.Set(fiber.HeaderContentType, fiber.MIMETextHTMLCharsetUTF8)
+	return c.Status(code).Send(content)
+}
diff --git a/internal/router/api-v1-email-verify.go b/internal/router/api-v1-email-verify.go
new file mode 100644
index 0000000..fad174b
--- /dev/null
+++ b/internal/router/api-v1-email-verify.go
@@ -0,0 +1,52 @@
+package router
+
+import (
+	"fmt"
+	"log/slog"
+	"net/url"
+	"strings"
+
+	"github.com/SayaAndy/saya-today-web/locale"
+	"github.com/gofiber/fiber/v2"
+)
+
+func init() {
+	assert(0, tm.Add("personal-page-status", "views/partials/personal-page-status.html"))
+}
+
+func Api_V1_Email_Verify(l map[string]*locale.LocaleConfig) func(c *fiber.Ctx) error {
+	return func(c *fiber.Ctx) error {
+		c.Set(fiber.HeaderContentType, fiber.MIMETextPlainCharsetUTF8)
+
+		referer := c.Get("Referer", "")
+		if referer == "" {
+			return c.Status(fiber.ErrBadRequest.Code).SendString("'Referer' header is empty")
+		}
+
+		urlStruct, err := url.ParseRequestURI(referer)
+		if err != nil {
+			return c.Status(fiber.ErrBadRequest.Code).SendString(fmt.Sprintf("'Referer' header is invalid: %s", err.Error()))
+		}
+
+		path := urlStruct.EscapedPath()
+		pathParts := strings.Split(strings.Trim(path, "/"), "/")
+		if len(pathParts) != 2 {
+			return c.Status(fiber.ErrBadRequest.Code).SendString("'Referer' header is invalid: expect format '/{lang}/user'")
+		}
+
+		lang := pathParts[0]
+
+		verificationCode := c.FormValue("email_code")
+		if verificationCode == "" {
+			return api_v1_email_sendStatusHtml(c, "verification-message", l, "Failed", fiber.ErrUnprocessableEntity.Code, lang, l[lang].UserProfile.VerificationEmpty, map[string]string{})
+		}
+
+		if err = Mailer.Verify(verificationCode, lang); err != nil {
+			slog.Error("verification code is invalid", slog.String("verification_code", verificationCode), slog.String("error", err.Error()))
+			return api_v1_email_sendStatusHtml(c, "verification-message", l, "Failed", fiber.ErrUnprocessableEntity.Code, lang, l[lang].UserProfile.VerificationFailed, map[string]string{})
+		}
+		return api_v1_email_sendStatusHtml(c, "verification-message", l, "OK", fiber.StatusOK, lang, l[lang].UserProfile.VerificationSuccess, map[string]string{
+			"hide-verification-panel": "true",
+		})
+	}
+}
diff --git a/internal/router/api-v1-general-page-body.go b/internal/router/api-v1-general-page-body.go
index fe21957..6f856d3 100644
--- a/internal/router/api-v1-general-page-body.go
+++ b/internal/router/api-v1-general-page-body.go
@@ -1,6 +1,7 @@
 package router
 
 import (
+	"bytes"
 	"fmt"
 	"html/template"
 	"log/slog"
@@ -14,15 +15,18 @@ import (
 	"github.com/SayaAndy/saya-today-web/config"
 	"github.com/SayaAndy/saya-today-web/internal/b2"
 	"github.com/SayaAndy/saya-today-web/internal/factgiver"
+	"github.com/SayaAndy/saya-today-web/internal/frontmatter"
+	"github.com/SayaAndy/saya-today-web/internal/mailer"
 	"github.com/SayaAndy/saya-today-web/locale"
 	"github.com/gofiber/fiber/v2"
 	"github.com/yuin/goldmark"
 )
 
 var FactGiver *factgiver.FactGiver
+var Mailer *mailer.Mailer
 
 func init() {
-	tm.Add("general-page-body", "views/partials/general-page-body.html")
+	assert(0, tm.Add("general-page-body", "views/partials/general-page-body.html"))
 }
 
 func Api_V1_GeneralPage_Body(l map[string]*locale.LocaleConfig, langs []config.AvailableLanguageConfig, b2Client *b2.B2Client, md goldmark.Markdown) func(c *fiber.Ctx) error {
@@ -39,15 +43,16 @@ func Api_V1_GeneralPage_Body(l map[string]*locale.LocaleConfig, langs []config.A
 		}
 
 		path := urlStruct.EscapedPath()
+		trimmedPath := strings.Trim(path, "/")
 
-		cacheKey := fmt.Sprintf("body.%s", path)
-		if val, ok := PCache.Get(cacheKey); val != nil && ok {
+		cacheKey := fmt.Sprintf("body.%s", trimmedPath)
+		if val, ok := PCache.Get(cacheKey); !strings.HasSuffix(trimmedPath, "user") && val != nil && ok {
 			c.Set(fiber.HeaderContentType, fiber.MIMETextHTMLCharsetUTF8)
 			return c.Status(fiber.StatusOK).Type("html").Send(val)
 		}
 
 		lang := ""
-		pathParts := strings.Split(strings.Trim(path, "/"), "/")
+		pathParts := strings.Split(trimmedPath, "/")
 		if len(pathParts) == 1 && pathParts[0] == "" {
 			pathParts = []string{}
 		}
@@ -123,6 +128,17 @@ func Api_V1_GeneralPage_Body(l map[string]*locale.LocaleConfig, langs []config.A
 			values["Title"] = l[lang].BlogSearch.Header
 
 			additionalTemplates = append(additionalTemplates, "views/pages/blog-catalogue.html")
+		} else if len(pathParts) == 2 && pathParts[1] == "user" {
+			values["Title"] = l[lang].UserProfile.Header
+
+			email, _, err := Mailer.GetInfo(c.IP())
+			if err != nil {
+				slog.Error("get info from mailer about a client", slog.String("error", err.Error()))
+			}
+			values["Email"] = email
+			values["EmailCode"] = c.Query("email_code")
+
+			additionalTemplates = append(additionalTemplates, "views/pages/user-page.html")
 		} else if len(pathParts) == 3 && pathParts[1] == "blog" {
 			metadata, parsedMarkdown, err := readBlogPost(md, b2Client, lang+"/"+pathParts[2])
 			if err != nil {
@@ -174,3 +190,17 @@ func Api_V1_GeneralPage_Body(l map[string]*locale.LocaleConfig, langs []config.A
 		return c.Status(fiber.StatusOK).Type("html").Send(content)
 	}
 }
+
+func readBlogPost(md goldmark.Markdown, b2Client *b2.B2Client, sourceName string) (metadata *frontmatter.Metadata, html string, err error) {
+	metadata, markdown, err := b2Client.ReadFrontmatter(sourceName + ".md")
+	if err != nil {
+		return nil, "", fmt.Errorf("failed to read a frontmatter file: %w", err)
+	}
+
+	var buf bytes.Buffer
+	if err := md.Convert(markdown, &buf); err != nil {
+		return nil, "", fmt.Errorf("convert source context from md to html: %w", err)
+	}
+
+	return metadata, buf.String(), nil
+}
diff --git a/internal/router/api-v1-general-page-bottom-embeds.go b/internal/router/api-v1-general-page-bottom-embeds.go
index 0a2030f..b408187 100644
--- a/internal/router/api-v1-general-page-bottom-embeds.go
+++ b/internal/router/api-v1-general-page-bottom-embeds.go
@@ -14,7 +14,7 @@ import (
 )
 
 func init() {
-	tm.Add("general-page-bottom-embeds", "views/partials/general-page-bottom-embeds.html")
+	assert(0, tm.Add("general-page-bottom-embeds", "views/partials/general-page-bottom-embeds.html"))
 }
 
 func Api_V1_GeneralPage_BottomEmbeds(l map[string]*locale.LocaleConfig, langs []config.AvailableLanguageConfig, b2Client *b2.B2Client) func(c *fiber.Ctx) error {
@@ -63,6 +63,8 @@ func Api_V1_GeneralPage_BottomEmbeds(l map[string]*locale.LocaleConfig, langs []
 
 		if len(pathParts) == 2 && pathParts[1] == "blog" {
 			additionalTemplates = append(additionalTemplates, "views/pages/blog-catalogue.html")
+		} else if len(pathParts) == 2 && pathParts[1] == "user" {
+			additionalTemplates = append(additionalTemplates, "views/pages/user-page.html")
 		} else if len(pathParts) == 3 && pathParts[1] == "blog" {
 			additionalTemplates = append(additionalTemplates, "views/pages/blog-page.html")
 		} else if len(pathParts) == 1 {
diff --git a/internal/router/api-v1-general-page-footer.go b/internal/router/api-v1-general-page-footer.go
index 2030b3b..99d899a 100644
--- a/internal/router/api-v1-general-page-footer.go
+++ b/internal/router/api-v1-general-page-footer.go
@@ -13,7 +13,7 @@ import (
 )
 
 func init() {
-	tm.Add("general-page-footer", "views/partials/general-page-footer.html")
+	assert(0, tm.Add("general-page-footer", "views/partials/general-page-footer.html"))
 }
 
 func Api_V1_GeneralPage_Footer(l map[string]*locale.LocaleConfig, langs []config.AvailableLanguageConfig) func(c *fiber.Ctx) error {
@@ -63,6 +63,8 @@ func Api_V1_GeneralPage_Footer(l map[string]*locale.LocaleConfig, langs []config
 
 		if len(pathParts) == 2 && pathParts[1] == "blog" {
 			additionalTemplates = append(additionalTemplates, "views/pages/blog-catalogue.html")
+		} else if len(pathParts) == 2 && pathParts[1] == "user" {
+			additionalTemplates = append(additionalTemplates, "views/pages/user-page.html")
 		} else if len(pathParts) == 3 && pathParts[1] == "blog" {
 			additionalTemplates = append(additionalTemplates, "views/pages/blog-page.html")
 		} else if len(pathParts) == 1 {
diff --git a/internal/router/api-v1-general-page-header.go b/internal/router/api-v1-general-page-header.go
index a2c832b..768417d 100644
--- a/internal/router/api-v1-general-page-header.go
+++ b/internal/router/api-v1-general-page-header.go
@@ -14,7 +14,7 @@ import (
 )
 
 func init() {
-	tm.Add("general-page-header", "views/partials/general-page-header.html")
+	assert(0, tm.Add("general-page-header", "views/partials/general-page-header.html"))
 }
 
 func Api_V1_GeneralPage_Header(l map[string]*locale.LocaleConfig, langs []config.AvailableLanguageConfig, b2Client *b2.B2Client) func(c *fiber.Ctx) error {
@@ -65,6 +65,9 @@ func Api_V1_GeneralPage_Header(l map[string]*locale.LocaleConfig, langs []config
 		if len(pathParts) == 2 && pathParts[1] == "blog" {
 			values["Title"] = l[lang].BlogSearch.Header
 			additionalTemplates = append(additionalTemplates, "views/pages/blog-catalogue.html")
+		} else if len(pathParts) == 2 && pathParts[1] == "user" {
+			values["Title"] = l[lang].UserProfile.Header
+			additionalTemplates = append(additionalTemplates, "views/pages/user-page.html")
 		} else if len(pathParts) == 3 && pathParts[1] == "blog" {
 			metadata, _, err := b2Client.ReadFrontmatter(lang + "/" + pathParts[2] + ".md")
 			if err != nil {
diff --git a/internal/router/api-v1-general-page-top-embeds.go b/internal/router/api-v1-general-page-top-embeds.go
index 544e3a4..f3e480b 100644
--- a/internal/router/api-v1-general-page-top-embeds.go
+++ b/internal/router/api-v1-general-page-top-embeds.go
@@ -13,7 +13,7 @@ import (
 )
 
 func init() {
-	tm.Add("general-page-top-embeds", "views/partials/general-page-top-embeds.html")
+	assert(0, tm.Add("general-page-top-embeds", "views/partials/general-page-top-embeds.html"))
 }
 
 func Api_V1_GeneralPage_TopEmbeds(l map[string]*locale.LocaleConfig, langs []config.AvailableLanguageConfig) func(c *fiber.Ctx) error {
@@ -63,6 +63,8 @@ func Api_V1_GeneralPage_TopEmbeds(l map[string]*locale.LocaleConfig, langs []con
 
 		if len(pathParts) == 2 && pathParts[1] == "blog" {
 			additionalTemplates = append(additionalTemplates, "views/pages/blog-catalogue.html")
+		} else if len(pathParts) == 2 && pathParts[1] == "user" {
+			additionalTemplates = append(additionalTemplates, "views/pages/user-page.html")
 		} else if len(pathParts) == 3 && pathParts[1] == "blog" {
 			additionalTemplates = append(additionalTemplates, "views/pages/blog-page.html")
 		} else if len(pathParts) == 1 {
diff --git a/internal/router/api-v1-general-page.go b/internal/router/api-v1-general-page.go
index a77fc5e..c8b4362 100644
--- a/internal/router/api-v1-general-page.go
+++ b/internal/router/api-v1-general-page.go
@@ -1,6 +1,7 @@
 package router
 
 import (
+	"fmt"
 	"log/slog"
 	"strings"
 
@@ -10,7 +11,7 @@ import (
 )
 
 func init() {
-	tm.Add("general-page", "views/layouts/general-page.html")
+	assert(0, tm.Add("general-page", "views/layouts/general-page.html"))
 }
 
 func Api_V1_GeneralPage(l map[string]*locale.LocaleConfig, langs []config.AvailableLanguageConfig) func(c *fiber.Ctx) error {
@@ -34,7 +35,8 @@ func Api_V1_GeneralPage(l map[string]*locale.LocaleConfig, langs []config.Availa
 		}
 
 	langIsAvailable:
-		cacheKey := "general-page." + lang
+		queryString := string(c.Request().URI().QueryString())
+		cacheKey := fmt.Sprintf("general-page.%s?%s", lang, queryString)
 		if val, ok := PCache.Get(cacheKey); val != nil && ok {
 			c.Set(fiber.HeaderContentType, fiber.MIMETextHTMLCharsetUTF8)
 			return c.Status(fiber.StatusOK).Type("html").Send(val)
@@ -43,7 +45,7 @@ func Api_V1_GeneralPage(l map[string]*locale.LocaleConfig, langs []config.Availa
 		content, err := tm.Render("general-page", fiber.Map{
 			"L":           l[lang],
 			"Lang":        lang,
-			"QueryString": string(c.Request().URI().QueryString()),
+			"QueryString": queryString,
 		})
 		if err != nil {
 			slog.Warn("failed to generate div", slog.String("path", path), slog.String("error", err.Error()))
diff --git a/internal/router/api-v1-like.go b/internal/router/api-v1-like.go
index 327dafa..323c457 100644
--- a/internal/router/api-v1-like.go
+++ b/internal/router/api-v1-like.go
@@ -13,7 +13,7 @@ import (
 )
 
 func init() {
-	tm.Add("blog-page-like-button", "views/partials/blog-page-like-button.html")
+	assert(0, tm.Add("blog-page-like-button", "views/partials/blog-page-like-button.html"))
 }
 
 func Api_V1_Like_Put(l map[string]*locale.LocaleConfig, b2 *b2.B2Client) func(c *fiber.Ctx) error {
diff --git a/internal/router/lang-blog-title.go b/internal/router/lang-blog-title.go
deleted file mode 100644
index 6e80671..0000000
--- a/internal/router/lang-blog-title.go
+++ /dev/null
@@ -1,86 +0,0 @@
-package router
-
-import (
-	"bytes"
-	"fmt"
-	"html/template"
-	"log/slog"
-	"strconv"
-	"strings"
-
-	"github.com/SayaAndy/saya-today-web/config"
-	"github.com/SayaAndy/saya-today-web/internal/b2"
-	"github.com/SayaAndy/saya-today-web/internal/frontmatter"
-	"github.com/SayaAndy/saya-today-web/locale"
-	"github.com/gofiber/fiber/v2"
-	"github.com/yuin/goldmark"
-)
-
-func init() {
-	tm.Add("blog-page", "views/layouts/general-page.html", "views/pages/blog-page.html")
-}
-
-func Lang_Blog_Title(l map[string]*locale.LocaleConfig, langs []config.AvailableLanguageConfig, b2Client *b2.B2Client, md goldmark.Markdown) func(c *fiber.Ctx) error {
-	return func(c *fiber.Ctx) error {
-		ip := c.IP()
-		slog.Debug("client entering blog page", slog.String("ip", ip), slog.String("page", c.Path()))
-
-		lang := c.Params("lang")
-		for _, availableLang := range langs {
-			if availableLang.Name == lang {
-				goto langIsAvailable
-			}
-		}
-		return c.Status(fiber.ErrNotFound.Code).SendString(fmt.Sprintf("server does not support '%s' language", lang))
-
-	langIsAvailable:
-		metadata, parsedMarkdown, err := readBlogPost(md, b2Client, lang+"/"+c.Params("title"))
-		if err != nil {
-			c.Set(fiber.HeaderContentType, fiber.MIMETextPlainCharsetUTF8)
-			return c.Status(fiber.ErrNotFound.Code).SendString(fmt.Sprintf("failed to find '%s' post", c.Params("title")))
-		}
-
-		geolocationParts := strings.Split(metadata.Geolocation, " ")
-		var x, y, areaError string
-		if len(geolocationParts) >= 2 {
-			x = geolocationParts[0]
-			y = geolocationParts[1]
-		}
-		if len(geolocationParts) >= 3 {
-			areaError = geolocationParts[2]
-		}
-
-		content, err := tm.Render("blog-page", fiber.Map{
-			"Title":                 metadata.Title,
-			"PublishedDate":         metadata.PublishedTime.Format("2006-01-02 15:04:05 -07:00"),
-			"PublishedYear":         strconv.Itoa(metadata.PublishedTime.Year()),
-			"ParsedMarkdown":        template.HTML(parsedMarkdown),
-			"MapLocationX":          x,
-			"MapLocationY":          y,
-			"MapLocationAreaMeters": areaError,
-			"Lang":                  lang,
-			"QueryString":           string(c.Request().URI().QueryString()),
-		})
-		if err != nil {
-			slog.Warn("failed to generate page", slog.String("page", "/"+lang+"/blog/"+c.Params("title")), slog.String("error", err.Error()))
-			c.Set(fiber.HeaderContentType, fiber.MIMETextPlainCharsetUTF8)
-			return c.Status(fiber.ErrInternalServerError.Code).SendString("failed to generate page")
-		}
-
-		return c.Type("html").Send(content)
-	}
-}
-
-func readBlogPost(md goldmark.Markdown, b2Client *b2.B2Client, sourceName string) (metadata *frontmatter.Metadata, html string, err error) {
-	metadata, markdown, err := b2Client.ReadFrontmatter(sourceName + ".md")
-	if err != nil {
-		return nil, "", fmt.Errorf("failed to read a frontmatter file: %w", err)
-	}
-
-	var buf bytes.Buffer
-	if err := md.Convert(markdown, &buf); err != nil {
-		return nil, "", fmt.Errorf("convert source context from md to html: %w", err)
-	}
-
-	return metadata, buf.String(), nil
-}
diff --git a/internal/router/lang-blog.go b/internal/router/lang-blog.go
deleted file mode 100644
index 960ac3d..0000000
--- a/internal/router/lang-blog.go
+++ /dev/null
@@ -1,98 +0,0 @@
-package router
-
-import (
-	"fmt"
-	"log/slog"
-	"net/url"
-	"regexp"
-	"slices"
-	"strings"
-
-	"github.com/SayaAndy/saya-today-web/config"
-	"github.com/SayaAndy/saya-today-web/internal/b2"
-	"github.com/SayaAndy/saya-today-web/locale"
-	"github.com/gofiber/fiber/v2"
-)
-
-func init() {
-	tm.Add("blog-catalogue", "views/layouts/general-page.html", "views/pages/blog-catalogue.html")
-}
-
-func Lang_Blog(l map[string]*locale.LocaleConfig, langs []config.AvailableLanguageConfig, b2Client *b2.B2Client) func(c *fiber.Ctx) error {
-	return func(c *fiber.Ctx) error {
-		lang := c.Params("lang")
-		for _, availableLang := range langs {
-			if availableLang.Name == lang {
-				goto langIsAvailable
-			}
-		}
-		return c.Status(fiber.ErrNotFound.Code).SendString(fmt.Sprintf("server does not support '%s' language", lang))
-
-	langIsAvailable:
-		querySort := c.Query("sort")
-		if querySort == "" {
-			querySort = "publicationDateDesc"
-		}
-
-		encodedQuery := c.Request().URI().QueryString()
-		re, err := regexp.Compile(`tags\[\]=([\w]+)`)
-		if err != nil {
-			slog.Warn("failed to generate regex for tags gathering", slog.String("error", err.Error()))
-			c.Set(fiber.HeaderContentType, fiber.MIMETextPlainCharsetUTF8)
-			return c.Status(fiber.ErrInternalServerError.Code).SendString("failed to generate regex for tags gathering")
-		}
-		decodedQuery, _ := url.QueryUnescape(string(encodedQuery))
-		matches := re.FindAllStringSubmatch(decodedQuery, -1)
-
-		queryTags := make([]string, 0, len(matches))
-		for _, match := range matches {
-			queryTags = append(queryTags, string(match[1]))
-		}
-
-		pages, err := b2Client.Scan(lang + "/")
-		status := fiber.StatusOK
-		if err != nil {
-			status = fiber.StatusPartialContent
-			pages = []*b2.BlogPage{}
-		}
-
-		tagsMap := make(map[string]int)
-		for _, page := range pages {
-			for _, tag := range page.Metadata.Tags {
-				tagsMap[tag]++
-			}
-		}
-		slog.Debug("enlist pages for catalogue", slog.Int("tag_count", len(tagsMap)), slog.Int("page_count", len(pages)), slog.String("path", c.Path()))
-
-		type Tag struct {
-			Name  string `json:"Name" yaml:"name"`
-			Count int    `json:"Count" yaml:"count"`
-		}
-
-		tagsArray := make([]Tag, 0, len(tagsMap))
-		for tag, count := range tagsMap {
-			tagsArray = append(tagsArray, Tag{tag, count})
-		}
-		slices.SortFunc(tagsArray, func(a Tag, b Tag) int {
-			return strings.Compare(a.Name, b.Name)
-		})
-
-		content, err := tm.Render("blog-catalogue", fiber.Map{
-			"QuerySort":     querySort,
-			"QueryTags":     strings.Join(queryTags, ","),
-			"QueryString":   string(c.Request().URI().QueryString()),
-			"Tags":          tagsArray,
-			"Lang":          lang,
-			"L":             l[lang],
-			"PublishedYear": "2025",
-			"Title":         l[lang].BlogSearch.Header,
-		})
-		if err != nil {
-			slog.Warn("failed to generate page", slog.String("path", c.Path()), slog.String("error", err.Error()))
-			c.Set(fiber.HeaderContentType, fiber.MIMETextPlainCharsetUTF8)
-			return c.Status(fiber.ErrInternalServerError.Code).SendString("failed to generate page")
-		}
-
-		return c.Type("html").Status(status).Send(content)
-	}
-}
diff --git a/internal/router/lang-map.go b/internal/router/lang-map.go
index a744f02..619b05b 100644
--- a/internal/router/lang-map.go
+++ b/internal/router/lang-map.go
@@ -13,7 +13,7 @@ import (
 )
 
 func init() {
-	tm.Add("global-map", "views/pages/global-map.html")
+	assert(0, tm.Add("global-map", "views/pages/global-map.html"))
 }
 
 func Lang_Map(l map[string]*locale.LocaleConfig, langs []config.AvailableLanguageConfig, b2Client *b2.B2Client) func(c *fiber.Ctx) error {
diff --git a/internal/router/root.go b/internal/router/root.go
deleted file mode 100644
index f4a0692..0000000
--- a/internal/router/root.go
+++ /dev/null
@@ -1,27 +0,0 @@
-package router
-
-import (
-	"log/slog"
-
-	"github.com/SayaAndy/saya-today-web/config"
-	"github.com/gofiber/fiber/v2"
-)
-
-func init() {
-	tm.Add("index", "views/index.html")
-}
-
-func Root(localeCfg []config.AvailableLanguageConfig) func(c *fiber.Ctx) error {
-	return func(c *fiber.Ctx) error {
-		content, err := tm.Render("index", fiber.Map{
-			"AvailableLanguages": localeCfg,
-		})
-		if err != nil {
-			slog.Warn("failed to generate page", slog.String("page", "/"), slog.String("error", err.Error()))
-			c.Set(fiber.HeaderContentType, fiber.MIMETextPlainCharsetUTF8)
-			return c.Status(fiber.ErrInternalServerError.Code).SendString("failed to generate page")
-		}
-
-		return c.Type("html").Send(content)
-	}
-}
diff --git a/internal/templatemanager/templatemanager.go b/internal/templatemanager/templatemanager.go
index eebc297..bafdee5 100644
--- a/internal/templatemanager/templatemanager.go
+++ b/internal/templatemanager/templatemanager.go
@@ -31,6 +31,7 @@ var templateFuncMap = template.FuncMap{
 		}
 		return items
 	},
+	"replace": strings.ReplaceAll,
 }
 
 func NewTemplateManager(templates ...TemplateManagerTemplates) (*TemplateManager, error) {