1 files changed, 115 insertions, 0 deletions
diff --git a/src/Infobox/Calculator.c b/src/Infobox/Calculator.c
new file mode 100644
index 0000000..b80ce21
--- /dev/null
+++ b/src/Infobox/Calculator.c
@@ -0,0 +1,115 @@
+#include "Calculator.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include <ctype.h>
+
+static char logic_log[4096];
+
+typedef struct {
+    const char *buffer;
+    int pos;
+} Parser;
+
+static double parse_expression(Parser *p);
+
+static void skip_ws(Parser *p) {
+    while (p->buffer[p->pos] == ' ') p->pos++;
+}
+
+static double parse_factor(Parser *p) {
+    skip_ws(p);
+    if (p->buffer[p->pos] == '-') {
+        p->pos++;
+        return -parse_factor(p);
+    }
+    if (p->buffer[p->pos] == '(') {
+        p->pos++;
+        double res = parse_expression(p);
+        if (p->buffer[p->pos] == ')') p->pos++;
+        return res;
+    }
+    char *endptr;
+    double val = strtod(&p->buffer[p->pos], &endptr);
+    p->pos = (int)(endptr - p->buffer);
+    return val;
+}
+
+static double parse_term(Parser *p) {
+    double left = parse_factor(p);
+    while (1) {
+        skip_ws(p);
+        char op = p->buffer[p->pos];
+        if (op == '*' || op == '/') {
+            p->pos++;
+            double right = parse_factor(p);
+            double old = left;
+            left = (op == '*') ? left * right : left / right;
+
+            char step[256];
+
+            snprintf(step, sizeof(step), "<div>%g %c %g = <b>%g</b></div>", old, op,
+                     right, left);
+            strncat(logic_log, step, sizeof(logic_log) - strlen(logic_log) - 1);
+        } else
+            break;
+    }
+    return left;
+}
+
+static double parse_expression(Parser *p) {
+    double left = parse_term(p);
+    while (1) {
+        skip_ws(p);
+        char op = p->buffer[p->pos];
+        if (op == '+' || op == '-') {
+            p->pos++;
+            double right = parse_term(p);
+            double old = left;
+            left = (op == '+') ? left + right : left - right;
+
+            char step[256];
+
+            snprintf(step, sizeof(step), "<div>%g %c %g = <b>%g</b></div>", old, op,
+                     right, left);
+            strncat(logic_log, step, sizeof(logic_log) - strlen(logic_log) - 1);
+        } else
+            break;
+    }
+    return left;
+}
+
+double evaluate(const char *expr) {
+    logic_log[0] = '\0';
+    if (!expr || strlen(expr) == 0) return 0.0;
+    Parser p = {expr, 0};
+    return parse_expression(&p);
+}
+
+InfoBox fetch_calc_data(char *math_input) {
+    InfoBox info = {NULL, NULL, NULL, NULL};
+    if (!math_input) return info;
+
+    double result = evaluate(math_input);
+
+    char html_output[5120];
+    snprintf(html_output, sizeof(html_output),
+             "<div class='calc-container' style='line-height: 1.6;'>"
+             "%s"
+             "<div style='margin-top: 8px; border-top: 1px solid #eee; "
+             "padding-top: 8px; font-size: 1.2em;'>"
+             "<b>%g</b>"
+             "</div>"
+             "</div>",
+             strlen(logic_log) > 0 ? logic_log : "<div>Constant value</div>",
+             result);
+
+    info.title = strdup("Calculation");
+    info.extract = strdup(html_output);
+    info.thumbnail_url =
+    strdup("/static/calculation.svg");
+    info.url = strdup("#");
+
+    return info;
+}