string editing ui

src/mem.c

         data_ram.data.wf[i] = wf_default_data[i];
     }
 
-    // TODO
+    // TODO better way to pre-define WiFi credentials
     data_ram.data.net_count = 1;
     strcpy(data_ram.data.net[0].name, DEFAULT_WIFI_SSID);
     strcpy(data_ram.data.net[0].pass, DEFAULT_WIFI_PASS);

src/state_string.c

  */
 
 #include <stdio.h>
+#include <string.h>
 
 #include "config.h"
 #include "buttons.h"
 static size_t str_len = 0;
 static const char *str_name = NULL;
 static enum system_state str_ret_state = STATE_SCAN;
+static size_t edit = 0, offset = 0;
 
 void state_string_set(char *value, size_t length,
                       const char *name) {
     if ((str_p == NULL) || (str_len <= 0) || (str_name == NULL)) {
         snprintf(buff, sizeof(buff), "error");
     } else {
-        snprintf(buff, sizeof(buff), "%s:\n\n%s", str_name, str_p);
+        snprintf(buff, sizeof(buff), "%s:\n\n'%s'", str_name, str_p + offset);
     }
 
-    text_box(buff, true,
+    text_box(buff, false,
              "fixed_10x20",
              0, LCD_WIDTH,
              50, MENU_BOX_HEIGHT(MENU_MAX_LINES, 20, 2),
              0);
+
+    size_t ch = edit - offset + 1;
+    lcd_write_rect(ch * 10,
+                   50 + 3 * 22,
+                   ch * 10 + 10,
+                   50 + 3 * 22 + 3,
+                   LCD_WHITE);
 }
 
 static void string_buttons(enum buttons btn, bool state) {
     if (state && (btn == BTN_Y)) {
         state_switch(str_ret_state);
     } else if (state && (btn == BTN_LEFT)) {
-        // TODO
+        if (edit > 0) {
+            edit--;
+        }
     } else if (state && (btn == BTN_RIGHT)) {
-        // TODO
+        if (edit < (str_len - 1)) {
+            edit++;
+        }
+        size_t l = strlen(str_p);
+        while (edit >= l) {
+            str_p[l++] = ' ';
+        }
     } else if (state && (btn == BTN_UP)) {
-        // TODO
+        char *c = str_p + edit;
+        if ((*c >= ' ') && (*c < '~')) {
+            (*c)++;
+        }
     } else if (state && (btn == BTN_DOWN)) {
-        // TODO
+        char *c = str_p + edit;
+        if ((*c > ' ') && (*c <= '~')) {
+            (*c)--;
+        }
+    } else if (state && (btn == BTN_B)) {
+        char *c = str_p + edit;
+        *c = '\0';
+    } else {
+        return;
+    }
+
+    while (edit < offset) {
+        offset -= 1;
     }
+    while (edit >= (offset + (LCD_WIDTH / 10 - 2))) {
+        offset += 1;
+    }
+
+    draw();
 }
 
 void state_string_enter(void) {
     buttons_callback(string_buttons);
+    edit = 0;
+    offset = 0;
     draw();
 }