diff --git a/examples/repl/cmdline.rs b/examples/repl/cmdline.rs
index b44863e5c..0e72396d1 100644
--- a/examples/repl/cmdline.rs
+++ b/examples/repl/cmdline.rs
@@ -222,10 +222,10 @@ unsafe fn log_msg(context: &Context, prefix: impl AsRef<str>, msg: *mut dc_msg_t
     let contact_name: *mut libc::c_char = dc_contact_get_name(contact);
     let contact_id: libc::c_int = dc_contact_get_id(contact) as libc::c_int;
     let statestr = match dc_msg_get_state(msg) {
-        20 => " o",
-        26 => " √",
-        28 => " √√",
-        24 => " !!",
+        DC_STATE_OUT_PENDING => " o",
+        DC_STATE_OUT_DELIVERED => " √",
+        DC_STATE_OUT_MDN_RCVD => " √√",
+        DC_STATE_OUT_FAILED => " !!",
         _ => "",
     };
     let temp2: *mut libc::c_char = dc_timestamp_to_str(dc_msg_get_timestamp(msg));
@@ -252,9 +252,9 @@ unsafe fn log_msg(context: &Context, prefix: impl AsRef<str>, msg: *mut dc_msg_t
         },
         if dc_msg_get_from_id(msg) == 1 as libc::c_uint {
             ""
-        } else if dc_msg_get_state(msg) == 16 {
+        } else if dc_msg_get_state(msg) == DC_STATE_IN_SEEN {
             "[SEEN]"
-        } else if dc_msg_get_state(msg) == 13 {
+        } else if dc_msg_get_state(msg) == DC_STATE_IN_NOTICED {
             "[NOTICED]"
         } else {
             "[FRESH]"
diff --git a/src/constants.rs b/src/constants.rs
index de50237fc..b9169111b 100644
--- a/src/constants.rs
+++ b/src/constants.rs
@@ -68,17 +68,17 @@ pub const DC_MSG_ID_MARKER1: usize = 1;
 pub const DC_MSG_ID_DAYMARKER: usize = 9;
 pub const DC_MSG_ID_LAST_SPECIAL: usize = 9;
 
-pub const DC_STATE_UNDEFINED: usize = 0;
-pub const DC_STATE_IN_FRESH: usize = 10;
-pub const DC_STATE_IN_NOTICED: usize = 13;
-pub const DC_STATE_IN_SEEN: usize = 16;
-pub const DC_STATE_OUT_PREPARING: usize = 18;
-pub const DC_STATE_OUT_DRAFT: usize = 19;
-pub const DC_STATE_OUT_PENDING: usize = 20;
-pub const DC_STATE_OUT_FAILED: usize = 24;
+pub const DC_STATE_UNDEFINED: i32 = 0;
+pub const DC_STATE_IN_FRESH: i32 = 10;
+pub const DC_STATE_IN_NOTICED: i32 = 13;
+pub const DC_STATE_IN_SEEN: i32 = 16;
+pub const DC_STATE_OUT_PREPARING: i32 = 18;
+pub const DC_STATE_OUT_DRAFT: i32 = 19;
+pub const DC_STATE_OUT_PENDING: i32 = 20;
+pub const DC_STATE_OUT_FAILED: i32 = 24;
 /// to check if a mail was sent, use dc_msg_is_sent()
-pub const DC_STATE_OUT_DELIVERED: usize = 26;
-pub const DC_STATE_OUT_MDN_RCVD: usize = 28;
+pub const DC_STATE_OUT_DELIVERED: i32 = 26;
+pub const DC_STATE_OUT_MDN_RCVD: i32 = 28;
 
 /// approx. max. length returned by dc_msg_get_text()
 pub const DC_MAX_GET_TEXT_LEN: usize = 30000;
@@ -98,29 +98,29 @@ pub const DC_CREATE_MVBOX: usize = 1;
 /// Text message.
 /// The text of the message is set using dc_msg_set_text()
 /// and retrieved with dc_msg_get_text().
-pub const DC_MSG_TEXT: usize = 10;
+pub const DC_MSG_TEXT: i32 = 10;
 
 /// Image message.
 /// If the image is an animated GIF, the type DC_MSG_GIF should be used.
 /// File, width and height are set via dc_msg_set_file(), dc_msg_set_dimension
 /// and retrieved via dc_msg_set_file(), dc_msg_set_dimension().
-pub const DC_MSG_IMAGE: usize = 20;
+pub const DC_MSG_IMAGE: i32 = 20;
 
 /// Animated GIF message.
 /// File, width and height are set via dc_msg_set_file(), dc_msg_set_dimension()
 /// and retrieved via dc_msg_get_file(), dc_msg_get_width(), dc_msg_get_height().
-pub const DC_MSG_GIF: usize = 21;
+pub const DC_MSG_GIF: i32 = 21;
 
 /// Message containing an Audio file.
 /// File and duration are set via dc_msg_set_file(), dc_msg_set_duration()
 /// and retrieved via dc_msg_get_file(), dc_msg_get_duration().
-pub const DC_MSG_AUDIO: usize = 40;
+pub const DC_MSG_AUDIO: i32 = 40;
 
 /// A voice message that was directly recorded by the user.
 /// For all other audio messages, the type #DC_MSG_AUDIO should be used.
 /// File and duration are set via dc_msg_set_file(), dc_msg_set_duration()
 /// and retrieved via dc_msg_get_file(), dc_msg_get_duration()
-pub const DC_MSG_VOICE: usize = 41;
+pub const DC_MSG_VOICE: i32 = 41;
 
 /// Video messages.
 /// File, width, height and durarion
@@ -128,12 +128,12 @@ pub const DC_MSG_VOICE: usize = 41;
 /// and retrieved via
 /// dc_msg_get_file(), dc_msg_get_width(),
 /// dc_msg_get_height(), dc_msg_get_duration().
-pub const DC_MSG_VIDEO: usize = 50;
+pub const DC_MSG_VIDEO: i32 = 50;
 
 /// Message containing any file, eg. a PDF.
 /// The file is set via dc_msg_set_file()
 /// and retrieved via dc_msg_get_file().
-pub const DC_MSG_FILE: usize = 60;
+pub const DC_MSG_FILE: i32 = 60;
 
 // Flags for configuring IMAP and SMTP servers.
 // These flags are optional
diff --git a/src/dc_chat.rs b/src/dc_chat.rs
index d1308d9ae..eef543171 100644
--- a/src/dc_chat.rs
+++ b/src/dc_chat.rs
@@ -359,7 +359,7 @@ pub unsafe fn dc_prepare_msg<'a>(
     if msg.is_null() || chat_id <= 9i32 as libc::c_uint {
         return 0i32 as uint32_t;
     }
-    (*msg).state = 18i32;
+    (*msg).state = DC_STATE_OUT_PREPARING;
     let msg_id: uint32_t = prepare_msg_common(context, chat_id, msg);
     context.call_cb(
         Event::MSGS_CHANGED,
@@ -369,6 +369,18 @@ pub unsafe fn dc_prepare_msg<'a>(
     return msg_id;
 }
 
+pub fn msgtype_has_file(msgtype: i32) -> bool {
+    match msgtype {
+        DC_MSG_IMAGE => true,
+        DC_MSG_GIF => true,
+        DC_MSG_AUDIO => true,
+        DC_MSG_VOICE => true,
+        DC_MSG_VIDEO => true,
+        DC_MSG_FILE => true,
+        _ => false,
+    }
+}
+
 unsafe fn prepare_msg_common<'a>(
     context: &'a Context,
     chat_id: uint32_t,
@@ -379,32 +391,29 @@ unsafe fn prepare_msg_common<'a>(
     let mut chat: *mut Chat = 0 as *mut Chat;
     (*msg).id = 0i32 as uint32_t;
     (*msg).context = context;
-    if (*msg).type_0 == 10i32 {
+    if (*msg).type_0 == DC_MSG_TEXT {
+; /* the caller should check if the message text is empty */
         current_block = 17281240262373992796;
-    } else if (*msg).type_0 == 20i32
-        || (*msg).type_0 == 21i32
-        || (*msg).type_0 == 40i32
-        || (*msg).type_0 == 41i32
-        || (*msg).type_0 == 50i32
-        || (*msg).type_0 == 60i32
-    {
+    } else if msgtype_has_file((*msg).type_0) {
         pathNfilename = dc_param_get((*msg).param, DC_PARAM_FILE as i32, 0 as *const libc::c_char);
         if pathNfilename.is_null() {
             error!(
                 context,
                 0,
                 "Attachment missing for message of type #{}.",
-                (*msg).type_0 as libc::c_int,
+                (*msg).type_0,
             );
             current_block = 2171833246886114521;
-        } else if (*msg).state == 18i32 && 0 == dc_is_blobdir_path(context, pathNfilename) {
+        } else if (*msg).state == DC_STATE_OUT_PREPARING
+            && 0 == dc_is_blobdir_path(context, pathNfilename)
+        {
             error!(context, 0, "Files must be created in the blob-directory.",);
             current_block = 2171833246886114521;
         } else if 0 == dc_make_rel_and_copy(context, &mut pathNfilename) {
             current_block = 2171833246886114521;
         } else {
             dc_param_set((*msg).param, DC_PARAM_FILE as i32, pathNfilename);
-            if (*msg).type_0 == 60i32 || (*msg).type_0 == 20i32 {
+            if (*msg).type_0 == DC_MSG_FILE || (*msg).type_0 == DC_MSG_IMAGE {
                 let mut better_type: libc::c_int = 0i32;
                 let mut better_mime: *mut libc::c_char = 0 as *mut libc::c_char;
                 dc_msg_guess_msgtype_from_suffix(pathNfilename, &mut better_type, &mut better_mime);
@@ -428,7 +437,7 @@ unsafe fn prepare_msg_common<'a>(
                 0,
                 "Attaching \"{}\" for message type #{}.",
                 as_str(pathNfilename),
-                (*msg).type_0 as libc::c_int,
+                (*msg).type_0
             );
             current_block = 17281240262373992796;
         }
@@ -437,7 +446,7 @@ unsafe fn prepare_msg_common<'a>(
             context,
             0,
             "Cannot send messages of type #{}.",
-            (*msg).type_0 as libc::c_int,
+            (*msg).type_0
         );
         current_block = 2171833246886114521;
     }
@@ -446,8 +455,8 @@ unsafe fn prepare_msg_common<'a>(
             dc_unarchive_chat(context, chat_id);
             chat = dc_chat_new(context);
             if dc_chat_load_from_db(chat, chat_id) {
-                if (*msg).state != 18i32 {
-                    (*msg).state = 20i32
+                if (*msg).state != DC_STATE_OUT_PREPARING {
+                    (*msg).state = DC_STATE_OUT_PENDING
                 }
                 (*msg).id =
                     prepare_msg_raw(context, chat, msg, dc_create_smeared_timestamp(context));
@@ -899,7 +908,7 @@ pub unsafe fn dc_send_msg<'a>(
     if msg.is_null() {
         return 0;
     }
-    if (*msg).state != 18 {
+    if (*msg).state != DC_STATE_OUT_PREPARING {
         if 0 == prepare_msg_common(context, chat_id, msg) {
             return 0;
         }
@@ -907,7 +916,7 @@ pub unsafe fn dc_send_msg<'a>(
         if chat_id != 0 && chat_id != (*msg).chat_id {
             return 0;
         }
-        dc_update_msg_state(context, (*msg).id, 20);
+        dc_update_msg_state(context, (*msg).id, DC_STATE_OUT_PENDING);
     }
     if 0 == dc_job_send_msg(context, (*msg).id) {
         return 0;
@@ -1004,19 +1013,13 @@ unsafe fn set_draft_raw(context: &Context, chat_id: uint32_t, msg: *mut dc_msg_t
     }
     // save new draft
     if !msg.is_null() {
-        if (*msg).type_0 == 10i32 {
+        if (*msg).type_0 == DC_MSG_TEXT {
             if (*msg).text.is_null() || *(*msg).text.offset(0isize) as libc::c_int == 0i32 {
                 current_block = 14513523936503887211;
             } else {
                 current_block = 4495394744059808450;
             }
-        } else if (*msg).type_0 == 20i32
-            || (*msg).type_0 == 21i32
-            || (*msg).type_0 == 40i32
-            || (*msg).type_0 == 41i32
-            || (*msg).type_0 == 50i32
-            || (*msg).type_0 == 60i32
-        {
+        } else if msgtype_has_file((*msg).type_0) {
             pathNfilename =
                 dc_param_get((*msg).param, DC_PARAM_FILE as i32, 0 as *const libc::c_char);
             if pathNfilename.is_null() {
@@ -1043,7 +1046,7 @@ unsafe fn set_draft_raw(context: &Context, chat_id: uint32_t, msg: *mut dc_msg_t
                     "INSERT INTO msgs (chat_id, from_id, timestamp, type, state, txt, param, hidden) \
                      VALUES (?,?,?, ?,?,?,?,?);",
                     params![
-                        chat_id as i32, 1, time(), (*msg).type_0, 19,
+                        chat_id as i32, 1, time(), (*msg).type_0, DC_STATE_OUT_DRAFT,
                         if !(*msg).text.is_null() {
                             as_str((*msg).text)
                         } else {
@@ -1068,7 +1071,7 @@ fn get_draft_msg_id(context: &Context, chat_id: u32) -> u32 {
         .query_row_col(
             context,
             "SELECT id FROM msgs WHERE chat_id=? AND state=?;",
-            params![chat_id as i32, 19],
+            params![chat_id as i32, DC_STATE_OUT_DRAFT],
             0,
         )
         .unwrap_or_default();
@@ -1210,8 +1213,8 @@ pub fn dc_marknoticed_chat(context: &Context, chat_id: u32) -> bool {
     if !context
         .sql
         .exists(
-            "SELECT id FROM msgs  WHERE chat_id=? AND state=10;",
-            params![chat_id as i32],
+            "SELECT id FROM msgs  WHERE chat_id=? AND state=?;",
+            params![chat_id as i32, DC_STATE_IN_FRESH],
         )
         .unwrap_or_default()
     {
@@ -1356,8 +1359,8 @@ pub fn dc_archive_chat(context: &Context, chat_id: u32, archive: libc::c_int) ->
         if sql::execute(
             context,
             &context.sql,
-            "UPDATE msgs SET state=13 WHERE chat_id=? AND state=10;",
-            params![chat_id as i32],
+            "UPDATE msgs SET state=? WHERE chat_id=? AND state=?;",
+            params![DC_STATE_IN_NOTICED, chat_id as i32, DC_STATE_IN_FRESH],
         )
         .is_err()
         {
@@ -1646,7 +1649,7 @@ pub unsafe fn dc_add_contact_to_chat_ex(
                         12326129973959287090 => {}
                         _ => {
                             if dc_param_get_int((*chat).param, DC_PARAM_UNPROMOTED as i32, 0) == 0 {
-                                (*msg).type_0 = 10;
+                                (*msg).type_0 = DC_MSG_TEXT;
                                 (*msg).text = dc_stock_system_msg(
                                     context,
                                     17,
@@ -1765,7 +1768,7 @@ pub unsafe fn dc_remove_contact_from_chat(
                 /* we should respect this - whatever we send to the group, it gets discarded anyway! */
                 if !contact.is_null() {
                     if dc_param_get_int((*chat).param, DC_PARAM_UNPROMOTED as i32, 0) == 0 {
-                        (*msg).type_0 = 10;
+                        (*msg).type_0 = DC_MSG_TEXT;
                         if (*contact).id == 1 as libc::c_uint {
                             dc_set_group_explicitly_left(context, (*chat).grpid);
                             (*msg).text = dc_stock_system_msg(
@@ -1880,7 +1883,7 @@ pub unsafe fn dc_set_chat_name(
                 .is_ok()
                 {
                     if dc_param_get_int((*chat).param, DC_PARAM_UNPROMOTED as i32, 0i32) == 0i32 {
-                        (*msg).type_0 = 10i32;
+                        (*msg).type_0 = DC_MSG_TEXT;
                         (*msg).text = dc_stock_system_msg(
                             context,
                             15i32,
@@ -1956,7 +1959,7 @@ pub unsafe fn dc_set_chat_profile_image(
                             {
                                 dc_param_set_int((*msg).param, DC_PARAM_CMD as i32, 3i32);
                                 dc_param_set((*msg).param, DC_PARAM_CMD_ARG as i32, new_image_rel);
-                                (*msg).type_0 = 10i32;
+                                (*msg).type_0 = DC_MSG_TEXT;
                                 (*msg).text = dc_stock_system_msg(
                                     context,
                                     if !new_image_rel.is_null() {
@@ -2057,7 +2060,7 @@ pub unsafe fn dc_forward_msgs(
             );
             dc_param_set((*msg).param, DC_PARAM_CMD as i32, 0 as *const libc::c_char);
             let new_msg_id: uint32_t;
-            if (*msg).state == 18i32 {
+            if (*msg).state == DC_STATE_OUT_PREPARING {
                 let fresh9 = curr_timestamp;
                 curr_timestamp = curr_timestamp + 1;
                 new_msg_id = prepare_msg_raw(context, chat, msg, fresh9);
@@ -2080,7 +2083,7 @@ pub unsafe fn dc_forward_msgs(
                 free(old_fwd as *mut libc::c_void);
                 (*msg).param = save_param
             } else {
-                (*msg).state = 20i32;
+                (*msg).state = DC_STATE_OUT_PENDING;
                 let fresh10 = curr_timestamp;
                 curr_timestamp = curr_timestamp + 1;
                 new_msg_id = prepare_msg_raw(context, chat, msg, fresh10);
@@ -2346,8 +2349,8 @@ pub fn dc_add_device_msg(context: &Context, chat_id: uint32_t, text: *const libc
             2,
             2,
             unsafe {dc_create_smeared_timestamp(context)},
-            10,
-            13,
+            DC_MSG_TEXT,
+            DC_STATE_IN_NOTICED,
             as_str(text),
             as_str(rfc724_mid),
         ]
diff --git a/src/dc_contact.rs b/src/dc_contact.rs
index 740a7fa9d..9fc72ba80 100644
--- a/src/dc_contact.rs
+++ b/src/dc_contact.rs
@@ -1,6 +1,6 @@
 use crate::aheader::EncryptPreference;
 use crate::config;
-use crate::constants::Event;
+use crate::constants::*;
 use crate::context::Context;
 use crate::dc_array::*;
 use crate::dc_e2ee::*;
@@ -32,8 +32,8 @@ pub fn dc_marknoticed_contact(context: &Context, contact_id: u32) {
     if sql::execute(
         context,
         &context.sql,
-        "UPDATE msgs SET state=13 WHERE from_id=? AND state=10;",
-        params![contact_id as i32],
+        "UPDATE msgs SET state=? WHERE from_id=? AND state=?;",
+        params![DC_STATE_IN_NOTICED, contact_id as i32, DC_STATE_IN_FRESH],
     )
     .is_ok()
     {
diff --git a/src/dc_imex.rs b/src/dc_imex.rs
index 78498f26c..408806f40 100644
--- a/src/dc_imex.rs
+++ b/src/dc_imex.rs
@@ -142,7 +142,7 @@ pub unsafe fn dc_initiate_key_transfer(context: &Context) -> *mut libc::c_char {
                         chat_id = dc_create_chat_by_contact_id(context, 1i32 as uint32_t);
                         if !(chat_id == 0i32 as libc::c_uint) {
                             msg = dc_msg_new_untyped(context);
-                            (*msg).type_0 = 60i32;
+                            (*msg).type_0 = DC_MSG_FILE;
                             dc_param_set((*msg).param, DC_PARAM_FILE as i32, setup_file_name);
                             dc_param_set(
                                 (*msg).param,
diff --git a/src/dc_job.rs b/src/dc_job.rs
index 9e395ba52..30cea91bd 100644
--- a/src/dc_job.rs
+++ b/src/dc_job.rs
@@ -5,7 +5,7 @@ use std::time::Duration;
 
 use rand::{thread_rng, Rng};
 
-use crate::constants::Event;
+use crate::constants::*;
 use crate::context::Context;
 use crate::dc_chat::*;
 use crate::dc_configure::*;
@@ -365,7 +365,11 @@ unsafe fn dc_job_do_DC_JOB_SEND(context: &Context, job: &mut dc_job_t) {
                             } else {
                                 dc_delete_file(context, filename);
                                 if 0 != job.foreign_id {
-                                    dc_update_msg_state(context, job.foreign_id, 26i32);
+                                    dc_update_msg_state(
+                                        context,
+                                        job.foreign_id,
+                                        DC_STATE_OUT_DELIVERED,
+                                    );
                                     let chat_id: i32 = context
                                         .sql
                                         .query_row_col(
@@ -1170,20 +1174,15 @@ pub unsafe fn dc_job_send_msg(context: &Context, msg_id: uint32_t) -> libc::c_in
         );
     } else {
         // no redo, no IMAP. moreover, as the data does not exist, there is no need in calling dc_set_msg_failed()
-        if (*mimefactory.msg).type_0 == 20i32
-            || (*mimefactory.msg).type_0 == 21i32
-            || (*mimefactory.msg).type_0 == 40i32
-            || (*mimefactory.msg).type_0 == 41i32
-            || (*mimefactory.msg).type_0 == 50i32
-            || (*mimefactory.msg).type_0 == 60i32
-        {
+        if msgtype_has_file((*mimefactory.msg).type_0) {
             let pathNfilename = dc_param_get(
                 (*mimefactory.msg).param,
                 DC_PARAM_FILE as i32,
                 0 as *const libc::c_char,
             );
             if !pathNfilename.is_null() {
-                if ((*mimefactory.msg).type_0 == 20i32 || (*mimefactory.msg).type_0 == 21i32)
+                if ((*mimefactory.msg).type_0 == DC_MSG_IMAGE
+                    || (*mimefactory.msg).type_0 == DC_MSG_GIF)
                     && 0 == dc_param_exists((*mimefactory.msg).param, DC_PARAM_WIDTH as i32)
                 {
                     let mut buf: *mut libc::c_uchar = 0 as *mut libc::c_uchar;
diff --git a/src/dc_mimefactory.rs b/src/dc_mimefactory.rs
index 4c024b06f..3c3ab5a1a 100644
--- a/src/dc_mimefactory.rs
+++ b/src/dc_mimefactory.rs
@@ -787,11 +787,11 @@ pub unsafe fn dc_mimefactory_render(mut factory: *mut dc_mimefactory_t) -> libc:
                 }
                 dc_msg_unref(meta);
             }
-            if (*msg).type_0 == DC_MSG_VOICE as libc::c_int
-                || (*msg).type_0 == DC_MSG_AUDIO as libc::c_int
-                || (*msg).type_0 == DC_MSG_VIDEO as libc::c_int
+            if (*msg).type_0 == DC_MSG_VOICE
+                || (*msg).type_0 == DC_MSG_AUDIO
+                || (*msg).type_0 == DC_MSG_VIDEO
             {
-                if (*msg).type_0 == DC_MSG_VOICE as libc::c_int {
+                if (*msg).type_0 == DC_MSG_VOICE {
                     mailimf_fields_add(
                         imf_fields,
                         mailimf_field_new_custom(
@@ -867,13 +867,7 @@ pub unsafe fn dc_mimefactory_render(mut factory: *mut dc_mimefactory_t) -> libc:
             free(fwdhint as *mut libc::c_void);
             free(placeholdertext as *mut libc::c_void);
             /* add attachment part */
-            if (*msg).type_0 == DC_MSG_IMAGE as libc::c_int
-                || (*msg).type_0 == DC_MSG_GIF as libc::c_int
-                || (*msg).type_0 == DC_MSG_AUDIO as libc::c_int
-                || (*msg).type_0 == DC_MSG_VOICE as libc::c_int
-                || (*msg).type_0 == DC_MSG_VIDEO as libc::c_int
-                || (*msg).type_0 == DC_MSG_FILE as libc::c_int
-            {
+            if msgtype_has_file((*msg).type_0) {
                 if 0 == is_file_size_okay(msg) {
                     let error: *mut libc::c_char = dc_mprintf(
                         b"Message exceeds the recommended %i MB.\x00" as *const u8
@@ -1194,7 +1188,7 @@ unsafe fn build_body_file(
     let mut filename_to_send: *mut libc::c_char = 0 as *mut libc::c_char;
     let mut filename_encoded: *mut libc::c_char = 0 as *mut libc::c_char;
     if !pathNfilename.is_null() {
-        if (*msg).type_0 == DC_MSG_VOICE as libc::c_int {
+        if (*msg).type_0 == DC_MSG_VOICE {
             let ts = chrono::Utc.timestamp((*msg).timestamp_sort as i64, 0);
 
             let suffix = if !suffix.is_null() {
@@ -1206,11 +1200,9 @@ unsafe fn build_body_file(
                 .format(&format!("voice-message_%Y-%m-%d_%H-%M-%S.{}", suffix))
                 .to_string();
             filename_to_send = to_cstring(res);
-        } else if (*msg).type_0 == DC_MSG_AUDIO as libc::c_int {
+        } else if (*msg).type_0 == DC_MSG_AUDIO {
             filename_to_send = dc_get_filename(pathNfilename)
-        } else if (*msg).type_0 == DC_MSG_IMAGE as libc::c_int
-            || (*msg).type_0 == DC_MSG_GIF as libc::c_int
-        {
+        } else if (*msg).type_0 == DC_MSG_IMAGE || (*msg).type_0 == DC_MSG_GIF {
             if base_name.is_null() {
                 base_name = b"image\x00" as *const u8 as *const libc::c_char
             }
@@ -1223,7 +1215,7 @@ unsafe fn build_body_file(
                     b"dat\x00" as *const u8 as *const libc::c_char
                 },
             )
-        } else if (*msg).type_0 == DC_MSG_VIDEO as libc::c_int {
+        } else if (*msg).type_0 == DC_MSG_VIDEO {
             filename_to_send = dc_mprintf(
                 b"video.%s\x00" as *const u8 as *const libc::c_char,
                 if !suffix.is_null() {
diff --git a/src/dc_msg.rs b/src/dc_msg.rs
index 841eb4fff..e303aaf12 100644
--- a/src/dc_msg.rs
+++ b/src/dc_msg.rs
@@ -127,14 +127,14 @@ pub unsafe fn dc_get_msg_info(context: &Context, msg_id: u32) -> *mut libc::c_ch
 
     ret += "State: ";
     match (*msg).state {
-        10 => ret += "Fresh",
-        13 => ret += "Noticed",
-        16 => ret += "Seen",
-        26 => ret += "Delivered",
-        24 => ret += "Failed",
-        28 => ret += "Read",
-        20 => ret += "Pending",
-        18 => ret += "Preparing",
+        DC_STATE_IN_FRESH => ret += "Fresh",
+        DC_STATE_IN_NOTICED => ret += "Noticed",
+        DC_STATE_IN_SEEN => ret += "Seen",
+        DC_STATE_OUT_DELIVERED => ret += "Delivered",
+        DC_STATE_OUT_FAILED => ret += "Failed",
+        DC_STATE_OUT_MDN_RCVD => ret += "Read",
+        DC_STATE_OUT_PENDING => ret += "Pending",
+        DC_STATE_OUT_PREPARING => ret += "Preparing",
         _ => ret += &format!("{}", (*msg).state),
     }
 
@@ -172,15 +172,15 @@ pub unsafe fn dc_get_msg_info(context: &Context, msg_id: u32) -> *mut libc::c_ch
     }
     free(p as *mut libc::c_void);
 
-    if (*msg).type_0 != 10 {
+    if (*msg).type_0 != DC_MSG_TEXT {
         ret += "Type: ";
         match (*msg).type_0 {
-            40 => ret += "Audio",
-            60 => ret += "File",
-            21 => ret += "GIF",
-            20 => ret += "Image",
-            50 => ret += "Video",
-            41 => ret += "Voice",
+            DC_MSG_AUDIO => ret += "Audio",
+            DC_MSG_FILE => ret += "File",
+            DC_MSG_GIF => ret += "GIF",
+            DC_MSG_IMAGE => ret += "Image",
+            DC_MSG_VIDEO => ret += "Video",
+            DC_MSG_VOICE => ret += "Voice",
             _ => ret += &format!("{}", (*msg).type_0),
         }
         ret += "\n";
@@ -237,7 +237,7 @@ pub unsafe fn dc_msg_new<'a>(context: &'a Context, viewtype: libc::c_int) -> *mu
     (*msg).context = context;
     (*msg).magic = 0x11561156i32 as uint32_t;
     (*msg).type_0 = viewtype;
-    (*msg).state = 0i32;
+    (*msg).state = 0;
     (*msg).param = dc_param_new();
 
     msg
@@ -304,7 +304,7 @@ pub unsafe fn dc_msg_guess_msgtype_from_suffix(
     mut ret_mime: *mut *mut libc::c_char,
 ) {
     let mut suffix: *mut libc::c_char = 0 as *mut libc::c_char;
-    let mut dummy_msgtype: libc::c_int = 0i32;
+    let mut dummy_msgtype: libc::c_int = 0;
     let mut dummy_buf: *mut libc::c_char = 0 as *mut libc::c_char;
     if !pathNfilename.is_null() {
         if ret_msgtype.is_null() {
@@ -313,37 +313,37 @@ pub unsafe fn dc_msg_guess_msgtype_from_suffix(
         if ret_mime.is_null() {
             ret_mime = &mut dummy_buf
         }
-        *ret_msgtype = 0i32;
+        *ret_msgtype = 0;
         *ret_mime = 0 as *mut libc::c_char;
         suffix = dc_get_filesuffix_lc(pathNfilename);
         if !suffix.is_null() {
             if strcmp(suffix, b"mp3\x00" as *const u8 as *const libc::c_char) == 0i32 {
-                *ret_msgtype = DC_MSG_AUDIO as libc::c_int;
+                *ret_msgtype = DC_MSG_AUDIO;
                 *ret_mime = dc_strdup(b"audio/mpeg\x00" as *const u8 as *const libc::c_char)
             } else if strcmp(suffix, b"aac\x00" as *const u8 as *const libc::c_char) == 0i32 {
-                *ret_msgtype = DC_MSG_AUDIO as libc::c_int;
+                *ret_msgtype = DC_MSG_AUDIO;
                 *ret_mime = dc_strdup(b"audio/aac\x00" as *const u8 as *const libc::c_char)
             } else if strcmp(suffix, b"mp4\x00" as *const u8 as *const libc::c_char) == 0i32 {
-                *ret_msgtype = DC_MSG_VIDEO as libc::c_int;
+                *ret_msgtype = DC_MSG_VIDEO;
                 *ret_mime = dc_strdup(b"video/mp4\x00" as *const u8 as *const libc::c_char)
             } else if strcmp(suffix, b"jpg\x00" as *const u8 as *const libc::c_char) == 0i32
                 || strcmp(suffix, b"jpeg\x00" as *const u8 as *const libc::c_char) == 0i32
             {
-                *ret_msgtype = DC_MSG_IMAGE as libc::c_int;
+                *ret_msgtype = DC_MSG_IMAGE;
                 *ret_mime = dc_strdup(b"image/jpeg\x00" as *const u8 as *const libc::c_char)
             } else if strcmp(suffix, b"png\x00" as *const u8 as *const libc::c_char) == 0i32 {
-                *ret_msgtype = DC_MSG_IMAGE as libc::c_int;
+                *ret_msgtype = DC_MSG_IMAGE;
                 *ret_mime = dc_strdup(b"image/png\x00" as *const u8 as *const libc::c_char)
             } else if strcmp(suffix, b"webp\x00" as *const u8 as *const libc::c_char) == 0i32 {
-                *ret_msgtype = DC_MSG_IMAGE as libc::c_int;
+                *ret_msgtype = DC_MSG_IMAGE;
                 *ret_mime = dc_strdup(b"image/webp\x00" as *const u8 as *const libc::c_char)
             } else if strcmp(suffix, b"gif\x00" as *const u8 as *const libc::c_char) == 0i32 {
-                *ret_msgtype = DC_MSG_GIF as libc::c_int;
+                *ret_msgtype = DC_MSG_GIF;
                 *ret_mime = dc_strdup(b"image/gif\x00" as *const u8 as *const libc::c_char)
             } else if strcmp(suffix, b"vcf\x00" as *const u8 as *const libc::c_char) == 0i32
                 || strcmp(suffix, b"vcard\x00" as *const u8 as *const libc::c_char) == 0i32
             {
-                *ret_msgtype = DC_MSG_FILE as libc::c_int;
+                *ret_msgtype = DC_MSG_FILE;
                 *ret_mime = dc_strdup(b"text/vcard\x00" as *const u8 as *const libc::c_char)
             }
         }
@@ -571,14 +571,14 @@ pub fn dc_markseen_msgs(context: &Context, msg_ids: *const u32, msg_cnt: usize)
     for (id, curr_state, curr_blocked) in msgs.into_iter() {
         if curr_blocked == 0 {
             if curr_state == 10 || curr_state == 13 {
-                dc_update_msg_state(context, id, 16);
+                dc_update_msg_state(context, id, DC_STATE_IN_SEEN);
                 info!(context, 0, "Seen message #{}.", id);
 
                 unsafe { dc_job_add(context, 130, id as i32, 0 as *const libc::c_char, 0) };
                 send_event = true;
             }
-        } else if curr_state == 10 {
-            dc_update_msg_state(context, id, 13);
+        } else if curr_state == DC_STATE_IN_FRESH {
+            dc_update_msg_state(context, id, DC_STATE_IN_NOTICED);
             send_event = true;
         }
     }
@@ -917,9 +917,13 @@ pub unsafe fn dc_msg_has_deviating_timestamp(msg: *const dc_msg_t) -> libc::c_in
 // TODO should return bool /rtn
 pub unsafe fn dc_msg_is_sent(msg: *const dc_msg_t) -> libc::c_int {
     if msg.is_null() || (*msg).magic != 0x11561156i32 as libc::c_uint {
-        return 0i32;
+        return 0;
+    }
+    if (*msg).state >= DC_STATE_OUT_DELIVERED {
+        1
+    } else {
+        0
     }
-    return if (*msg).state >= 26i32 { 1i32 } else { 0i32 };
 }
 
 // TODO should return bool /rtn
@@ -961,16 +965,14 @@ pub unsafe fn dc_msg_is_info(msg: *const dc_msg_t) -> libc::c_int {
 // TODO should return bool /rtn
 pub unsafe fn dc_msg_is_increation(msg: *const dc_msg_t) -> libc::c_int {
     if msg.is_null() || (*msg).magic != 0x11561156i32 as libc::c_uint {
-        return 0i32;
+        return 0;
     }
 
-    (((*msg).type_0 == DC_MSG_IMAGE as libc::c_int
-        || (*msg).type_0 == DC_MSG_GIF as libc::c_int
-        || (*msg).type_0 == DC_MSG_AUDIO as libc::c_int
-        || (*msg).type_0 == DC_MSG_VOICE as libc::c_int
-        || (*msg).type_0 == DC_MSG_VIDEO as libc::c_int
-        || (*msg).type_0 == DC_MSG_FILE as libc::c_int)
-        && (*msg).state == 18i32) as libc::c_int
+    if msgtype_has_file((*msg).type_0) && (*msg).state == DC_STATE_OUT_PREPARING {
+        1
+    } else {
+        0
+    }
 }
 
 pub unsafe fn dc_msg_is_setupmessage(msg: *const dc_msg_t) -> bool {
@@ -1046,7 +1048,6 @@ pub unsafe fn dc_msg_set_text(mut msg: *mut dc_msg_t, text: *const libc::c_char)
     (*msg).text = dc_strdup(text);
 }
 
-// TODO should return bool /rtn
 pub unsafe fn dc_msg_set_file(
     msg: *mut dc_msg_t,
     file: *const libc::c_char,
@@ -1177,12 +1178,18 @@ pub fn dc_update_msg_move_state(
     .is_ok()
 }
 
+fn msgstate_can_fail(state: i32) -> bool {
+    return DC_STATE_OUT_PREPARING == state
+        || DC_STATE_OUT_PENDING == state
+        || DC_STATE_OUT_DELIVERED == state;
+}
+
 pub unsafe fn dc_set_msg_failed(context: &Context, msg_id: uint32_t, error: *const libc::c_char) {
     let mut msg = dc_msg_new_untyped(context);
 
     if dc_msg_load_from_db(msg, context, msg_id) {
-        if 18 == (*msg).state || 20 == (*msg).state || 26 == (*msg).state {
-            (*msg).state = 24
+        if msgstate_can_fail((*msg).state) {
+            (*msg).state = DC_STATE_OUT_FAILED;
         }
         if !error.is_null() {
             dc_param_set((*msg).param, DC_PARAM_ERROR as i32, error);
@@ -1247,8 +1254,10 @@ pub unsafe fn dc_mdn_from_ext(
         *ret_msg_id = msg_id as u32;
         *ret_chat_id = chat_id as u32;
 
-        if !(msg_state != 18 && msg_state != 20 && msg_state != 26) {
-            /* eg. already marked as MDNS_RCVD. however, it is importent, that the message ID is set above as this will allow the caller eg. to move the message away */
+        /* if already marked as MDNS_RCVD msgstate_can_fail() returns false.
+        however, it is important, that ret_msg_id is set above as this
+        will allow the caller eg. to move the message away */
+        if msgstate_can_fail(msg_state) {
             let mdn_already_in_table = context
                 .sql
                 .exists(
@@ -1266,7 +1275,7 @@ pub unsafe fn dc_mdn_from_ext(
 
             // Normal chat? that's quite easy.
             if chat_type == 100 {
-                dc_update_msg_state(context, *ret_msg_id, 28);
+                dc_update_msg_state(context, *ret_msg_id, DC_STATE_OUT_MDN_RCVD);
                 read_by_all = 1;
             } else {
                 /* send event about new state */
@@ -1293,11 +1302,10 @@ pub unsafe fn dc_mdn_from_ext(
                  */
                 // for rounding, SELF is already included!
                 let soll_cnt = (dc_get_chat_contact_cnt(context, *ret_chat_id) + 1) / 2;
-                if !(ist_cnt < soll_cnt) {
-                    /* wait for more receipts */
-                    dc_update_msg_state(context, *ret_msg_id, 28);
+                if ist_cnt >= soll_cnt {
+                    dc_update_msg_state(context, *ret_msg_id, DC_STATE_OUT_MDN_RCVD);
                     read_by_all = 1;
-                }
+                } /* else wait for more receipts */
             }
         }
     }
diff --git a/src/dc_securejoin.rs b/src/dc_securejoin.rs
index ef2fdfc11..41c90238b 100644
--- a/src/dc_securejoin.rs
+++ b/src/dc_securejoin.rs
@@ -2,7 +2,7 @@ use mmime::mailimf_types::*;
 use percent_encoding::{utf8_percent_encode, DEFAULT_ENCODE_SET};
 
 use crate::aheader::EncryptPreference;
-use crate::constants::Event;
+use crate::constants::*;
 use crate::context::Context;
 use crate::dc_array::*;
 use crate::dc_chat::*;
@@ -261,7 +261,7 @@ unsafe fn send_handshake_msg(
     grpid: *const libc::c_char,
 ) {
     let mut msg: *mut dc_msg_t = dc_msg_new_untyped(context);
-    (*msg).type_0 = 10i32;
+    (*msg).type_0 = DC_MSG_TEXT;
     (*msg).text = dc_mprintf(
         b"Secure-Join: %s\x00" as *const u8 as *const libc::c_char,
         step,