feat(args): args_handler error handling and print_usage

src/main.c

@@ -1,8 +1,19 @@
 // all includes
 
+#include <stdio.h>
+
+#include "utils/args/args.h"
+
 int main(int argc, char **argv)
 {
-    (void)argc;
+    struct args_options options;
-    (void)argv;
+    int r = args_handler(argc, argv, &options);
+    if (r != 0)
+    {
+        print_usage(stderr, argv[0]);
+        return 2;
+    }
+
+    args_print(&options);
     return 0;
 }

src/utils/args/args.c

@@ -21,10 +21,19 @@ int args_handler(int argc, char **argv, struct args_options *options)
         {
             options->verbose = true;
         }
-        else if (strcmp(argv[i], "-c") == 0 && i + 1 < argc)
+        else if (strcmp(argv[i], "-c") == 0)
         {
             if (options->type != INPUT_UNDEFINED)
-                return 1; // Error: multiple input types specified
+            {
+                fprintf(stderr, "Multiple input sources specified: %s\n",
+                        argv[i + 1]);
+                return 1;
+            }
+            else if (i + 1 >= argc)
+            {
+                fprintf(stderr, "No command provided after -c\n");
+                return 1;
+            }
 
             options->type = INPUT_CMD;
             options->input_source = argv[i + 1];
@@ -32,12 +41,17 @@ int args_handler(int argc, char **argv, struct args_options *options)
         }
         else if (argv[i][0] == '-')
         {
-            return 1; // Error: unknown option
+            fprintf(stderr, "Unknown option: %s\n", argv[i]);
+            return 1;
         }
         else
         {
             if (options->type != INPUT_UNDEFINED)
-                return 1; // Error: multiple input types specified
+            {
+                fprintf(stderr, "Multiple input sources specified: %s\n",
+                        argv[i]);
+                return 1;
+            }
 
             options->type = INPUT_FILE;
             options->input_source = argv[i];
@@ -62,3 +76,14 @@ void args_print(struct args_options *options)
     printf("Pretty print: %s\n", options->pretty_print ? "true" : "false");
     printf("Verbose: %s\n", options->verbose ? "true" : "false");
 }
+
+void print_usage(FILE *std, const char *program_name)
+{
+    fprintf(std, "Usage: %s [OPTIONS] [SCRIPT] [ARGUMENTS...]\n", program_name);
+    fprintf(std, "Options:\n");
+    fprintf(std, "  -c [SCRIPT]        Execute the given command string.\n");
+    fprintf(std, "  --pretty-print     Enable pretty printing of outputs.\n");
+    fprintf(std, "  --verbose          Enable verbose mode.\n");
+    fprintf(std,
+            "If no SCRIPT is provided, input is read from standard input.\n");
+}

src/utils/args/args.h

@@ -2,6 +2,7 @@
 #define ARGS_H
 
 #include <stdbool.h>
+#include <stdio.h>
 
 enum input_type
 {
@@ -38,4 +39,10 @@ int args_handler(int argc, char **argv, struct args_options *options);
  */
 void args_print(struct args_options *options);
 
+/** Prints the usage information for the program.
+ * @param std The output stream to print to (e.g., stdout or stderr).
+ * @param program_name The name of the program.
+ */
+void print_usage(FILE *std, const char *program_name);
+
 #endif /* ARGS_H */

tests/unit/utils/args.c

@@ -0,0 +1,134 @@
+#include "../../../src/utils/args/args.h"
+
+#include <criterion/criterion.h>
+#include <criterion/new/assert.h>
+#include <criterion/redirect.h>
+
+TestSuite(utils_args);
+
+Test(utils_args, basic_command)
+{
+    int argc = 3;
+    struct args_options options;
+    char *input[] = { "program", "-c", "echo Hello, World!" };
+
+    int r = args_handler(argc, input, &options);
+
+    cr_expect(r == 0);
+    cr_expect(options.pretty_print == false);
+    cr_expect(options.verbose == false);
+    cr_expect(options.type == INPUT_CMD);
+    cr_expect(eq(options.input_source, "echo Hello, World!"));
+}
+
+Test(utils_args, basic_command_with_flags)
+{
+    int argc = 5;
+    struct args_options options;
+    char *input[] = { "program", "--pretty-print", "-c", "echo Hello, World!",
+                      "--verbose" };
+
+    int r = args_handler(argc, input, &options);
+
+    cr_expect(r == 0);
+    cr_expect(options.pretty_print == true);
+    cr_expect(options.verbose == true);
+    cr_expect(options.type == INPUT_CMD);
+    cr_expect(eq(options.input_source, "echo Hello, World!"));
+}
+
+Test(utils_args, basic_file_input)
+{
+    int argc = 2;
+    struct args_options options;
+    char *input[] = { "program", "input.txt" };
+
+    int r = args_handler(argc, input, &options);
+
+    cr_expect(r == 0);
+    cr_expect(options.pretty_print == false);
+    cr_expect(options.verbose == false);
+    cr_expect(options.type == INPUT_FILE);
+    cr_expect(eq(options.input_source, "input.txt"));
+}
+
+Test(utils_args, basic_file_input_with_flags)
+{
+    int argc = 4;
+    struct args_options options;
+    char *input[] = { "program", "--verbose", "input.txt", "--pretty-print" };
+
+    int r = args_handler(argc, input, &options);
+
+    cr_expect(r == 0);
+    cr_expect(options.pretty_print == true);
+    cr_expect(options.verbose == true);
+    cr_expect(options.type == INPUT_FILE);
+    cr_expect(eq(options.input_source, "input.txt"));
+}
+
+Test(utils_args, basic_stdin_input)
+{
+    int argc = 1;
+    struct args_options options;
+    char *input[] = { "program" };
+
+    int r = args_handler(argc, input, &options);
+
+    cr_expect(r == 0);
+    cr_expect(options.pretty_print == false);
+    cr_expect(options.verbose == false);
+    cr_expect(options.type == INPUT_STDIN);
+    cr_expect(options.input_source == NULL);
+}
+
+Test(utils_args, pretty_print_and_verbose_flags)
+{
+    int argc = 3;
+    struct args_options options;
+    char *input[] = { "program", "--pretty-print", "--verbose" };
+
+    int r = args_handler(argc, input, &options);
+
+    cr_expect(r == 0);
+    cr_expect(options.pretty_print == true);
+    cr_expect(options.verbose == true);
+    cr_expect(options.type == INPUT_STDIN);
+    cr_expect(options.input_source == NULL);
+}
+
+Test(utils_args, missing_command_after_c, .init = cr_redirect_stderr)
+{
+    int argc = 2;
+    struct args_options options;
+    char *input[] = { "program", "-c" };
+
+    int r = args_handler(argc, input, &options);
+
+    cr_expect(r != 0);
+    cr_assert_stderr_eq_str("No command provided after -c\n");
+}
+
+Test(utils_args, unknown_option, .init = cr_redirect_stderr)
+{
+    int argc = 2;
+    struct args_options options;
+    char *input[] = { "program", "--unknown" };
+
+    int r = args_handler(argc, input, &options);
+
+    cr_expect(r != 0);
+    cr_assert_stderr_eq_str("Unknown option: --unknown\n");
+}
+
+Test(utils_args, conflicting_input_types, .init = cr_redirect_stderr)
+{
+    int argc = 4;
+    struct args_options options;
+    char *input[] = { "program", "-c", "echo Hello", "input.txt" };
+
+    int r = args_handler(argc, input, &options);
+
+    cr_expect(r != 0);
+    cr_assert_stderr_eq_str("Multiple input sources specified: input.txt\n");
+}