1 files changed, 119 insertions, 0 deletions
diff --git a/utils/help.h b/utils/help.h
new file mode 100644
index 000000000..dc7f270d9
--- /dev/null
+++ b/utils/help.h
@@ -0,0 +1,119 @@
+
+#include <stdio.h>
+#include <string.h>
+
+/*
+ * List command groups.
+ */
+
+#define GROUPS \
+  G(UNKNOWN, "unknown") \
+  G(SET, "set") \
+  G(LIST, "list") \
+  G(HASH, "hash") \
+  G(GENERIC, "generic") \
+  G(PUBSUB, "pubsub") \
+  G(STRING, "string") \
+  G(SERVER, "server") \
+  G(CONNECTION, "connection") \
+  G(TRANSACTIONS, "transactions") \
+  G(SORTED_SET, "sorted_set")
+
+/*
+ * Command group types.
+ */
+
+typedef enum {
+  #define G(GROUP, _) COMMAND_GROUP_##GROUP,
+  GROUPS
+  #undef G
+  COMMAND_GROUP_LENGTH
+} command_group_type_t;
+
+/*
+ * Command group type names.
+ */
+
+static char *command_group_type_names[] = {
+  #define G(_, STR) STR,
+  GROUPS
+  #undef G
+};
+
+/*
+ * Command help struct.
+ */
+
+struct command_help {
+  char *name;
+  char *params;
+  char *summary;
+  command_group_type_t group;
+  char *since;
+} command_help[] = {
+  __COMMANDS__
+};
+
+/*
+ * Output command help to stdout.
+ */
+
+static void
+output_command_help(struct command_help *help) {
+  printf("\n  \x1b[1m%s\x1b[0m \x1b[90m%s\x1b[0m\n", help->name, help->params);
+  printf("  \x1b[33msummary:\x1b[0m %s\n", help->summary);
+  printf("  \x1b[33msince:\x1b[0m %s\n", help->since);
+  printf("  \x1b[33mgroup:\x1b[0m %s\n", command_group_type_names[help->group]);
+}
+
+/*
+ * Return command group type by name string.
+ */
+
+static command_group_type_t
+command_group_type_by_name(const char *name) {
+  for (int i = 0; i < COMMAND_GROUP_LENGTH; ++i) {
+    const char *group = command_group_type_names[i];
+    if (0 == strcasecmp(name, group)) return i;
+  }
+  return 0;
+}
+
+/*
+ * Output group names.
+ */
+
+static void
+output_group_help() {
+	for (int i = 0; i < COMMAND_GROUP_LENGTH; ++i) {
+		if (COMMAND_GROUP_UNKNOWN == i) continue;
+		const char *group = command_group_type_names[i];
+		printf("  \x1b[90m-\x1b[0m %s\n", group);
+	}
+}
+
+/*
+ * Output all command help, filtering by group or command name.
+ */
+
+static void
+output_help(int argc, const char **argv) {
+  int len = sizeof(command_help) / sizeof(struct command_help);
+
+	if (argc && 0 == strcasecmp("groups", argv[0])) {
+		output_group_help();
+		return;
+	}
+
+	command_group_type_t group = argc
+    ? command_group_type_by_name(argv[0])
+    : COMMAND_GROUP_UNKNOWN;
+
+  for (int i = 0; i < len; ++i) {
+    struct command_help help = command_help[i];
+    if (argc && !group && 0 != strcasecmp(help.name, argv[0])) continue;
+    if (group && group != help.group) continue;
+    output_command_help(&help);
+  }
+  puts("");
+}
+\ No newline at end of file