1 files changed, 102 insertions, 0 deletions
diff --git a/src/c/fastforge_csv.c b/src/c/fastforge_csv.c
new file mode 100644
index 0000000..7da9bd7
--- /dev/null
+++ b/src/c/fastforge_csv.c
@@ -0,0 +1,102 @@
+#include "fastforge_csv.h"
+
+#include <stdbool.h>
+#include <stdio.h>
+
+size_t csv_append_text(char *buffer, size_t size, size_t offset,
+                       const char *value) {
+  if (!buffer || size == 0 || offset >= size) {
+    return offset;
+  }
+
+  bool needs_quotes = false;
+  if (value) {
+    for (const char *cursor = value; *cursor; cursor++) {
+      if (*cursor == ',' || *cursor == '"' || *cursor == '\n' ||
+          *cursor == '\r') {
+        needs_quotes = true;
+        break;
+      }
+    }
+  }
+
+  if (needs_quotes) {
+    if (offset + 1 < size) {
+      buffer[offset++] = '"';
+    }
+    if (value) {
+      for (const char *cursor = value; *cursor && offset + 1 < size; cursor++) {
+        if (*cursor == '"') {
+          if (offset + 2 >= size) {
+            break;
+          }
+          buffer[offset++] = '"';
+          buffer[offset++] = '"';
+        } else {
+          buffer[offset++] = *cursor;
+        }
+      }
+    }
+    if (offset + 1 < size) {
+      buffer[offset++] = '"';
+    }
+  } else if (value) {
+    for (const char *cursor = value; *cursor && offset + 1 < size; cursor++) {
+      buffer[offset++] = *cursor;
+    }
+  }
+
+  if (offset < size) {
+    buffer[offset] = '\0';
+  }
+  return offset;
+}
+
+size_t csv_append_int(char *buffer, size_t size, size_t offset, long value) {
+  char number_text[16];
+  snprintf(number_text, sizeof(number_text), "%ld", value);
+  return csv_append_text(buffer, size, offset, number_text);
+}
+
+void format_history_csv_row(const FastEntry *entry, char *buffer, size_t size) {
+  if (!buffer || size == 0) {
+    return;
+  }
+
+  buffer[0] = '\0';
+  if (!entry) {
+    return;
+  }
+
+  size_t offset = 0;
+  offset = csv_append_int(buffer, size, offset, (long)entry->start_time);
+  if (offset + 1 < size) {
+    buffer[offset++] = ',';
+    buffer[offset] = '\0';
+  }
+  offset = csv_append_int(buffer, size, offset, (long)entry->end_time);
+  if (offset + 1 < size) {
+    buffer[offset++] = ',';
+    buffer[offset] = '\0';
+  }
+  offset = csv_append_int(buffer, size, offset, (long)entry->target_minutes);
+  if (offset + 1 < size) {
+    buffer[offset++] = ',';
+    buffer[offset] = '\0';
+  }
+  offset = csv_append_text(buffer, size, offset, entry->note);
+  if (offset + 1 < size) {
+    buffer[offset++] = ',';
+    buffer[offset] = '\0';
+  }
+  (void)csv_append_int(buffer, size, offset, (long)entry->max_stage_reached);
+}
+
+void format_history_csv_header(char *buffer, size_t size) {
+  if (!buffer || size == 0) {
+    return;
+  }
+
+  snprintf(buffer, size,
+           "start_time,end_time,target_minutes,note,max_stage_reached");
+}