From 9a2f1f14c18532e79bb8f0a003eb43256d7e7677 Mon Sep 17 00:00:00 2001
From: Erik Nyquist <eknyquist@gmail.com>
Date: Sat, 21 Oct 2023 14:00:02 -0700
Subject: [PATCH] C support working

---
 duckargs/__init__.py | 84 ++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 78 insertions(+), 6 deletions(-)

diff --git a/duckargs/__init__.py b/duckargs/__init__.py
index 7fa01d6..7f16d7d 100644
--- a/duckargs/__init__.py
+++ b/duckargs/__init__.py
@@ -33,6 +33,12 @@ def main():
 
 int main(int argc, char *argv[])
 {{
+    if (argc < 2)
+    {{
+        print_usage();
+        return -1;
+    }}
+
     int ret = parse_args(argc, argv);
     if (0 != ret)
     {{
@@ -414,6 +420,19 @@ def _generate_c_getopt_code(processed_args, getopt_string, opts, positionals, ha
 
         if positionals:
             # Has both positionals and opts
+            ret += f"    if (argc < (optind + {len(positionals)}))\n"
+            ret += f"    {{\n"
+            ret += f"        printf(\"Missing positional arguments\\n\");\n"
+            ret += f"        return -1;\n"
+            ret += f"    }}\n\n"
+
+            for i in range(len(positionals)):
+                arg = positionals[i]
+                desc = f"Positional argument #{i + 1} ({arg.var_name})"
+                optarg = f"argv[optind]"
+                ret += '\n'.join(["    " + x for x in _generate_c_opt_lines(arg, desc, optarg)])
+                ret += "\n    optind++;\n\n"
+
             pass
 
     elif positionals:
@@ -462,26 +481,68 @@ def _generate_c_print_code(processed_args):
 def _generate_c_usage_code(processed_args):
     lines = []
     positionals = []
-    has_opts = False
+    opts = []
 
     for arg in processed_args:
         if arg.is_positional():
             positionals.append(arg)
-            continue
         else:
-            has_opts = True
+            opts.append(arg)
+
+    lines.append("")
 
     line = "program_name"
-    if has_opts:
+    if opts:
         line += " [OPTIONS]"
 
     if positionals:
         positional_names = ' '.join([x.var_name for x in positionals])
         line += f" {positional_names}"
 
-    lines.append(line + "\\n\\n")
+    lines.append(line + "\\n")
+
+    if opts:
+        longest_left_col = 0
+        usage_lines = []
+
+        for opt in opts:
+            left_col = opt.opt
+            if opt.longopt is not None:
+                left_col += " " + opt.longopt
+
+            arg = None
+            right_col = ""
+            if opt.is_flag():
+                right_col = "A flag"
+            else:
+                if ArgType.INT == opt.type:
+                    right_col = "An int value"
+                    arg = " [int]"
+                elif ArgType.FLOAT == opt.type:
+                    right_col = "A float value"
+                    arg = " [float]"
+                elif ArgType.STRING == opt.type:
+                    right_col = "A string value"
+                    arg = " [string]"
+                elif ArgType.FILE == opt.type:
+                    right_col = "A filename"
+                    arg = " FILE"
+
+            if arg is not None:
+                left_col += arg
+
+            if len(left_col) > longest_left_col:
+                longest_left_col = len(left_col)
 
-    return '\n'.join([f"    printf(\"{line}\");" for line in lines])
+            usage_lines.append((left_col, right_col))
+
+        for leftcol, rightcol in usage_lines:
+            num_spaces = (longest_left_col + 2) - len(leftcol)
+            lines.append(leftcol + (" " * num_spaces) + rightcol)
+
+    lines.append("")
+
+    return '\n'.join([f"    printf(\"{line}\\n\");" for line in lines])
 
 def generate_c_code(argv=sys.argv):
     """
@@ -548,6 +609,17 @@ def generate_c_code(argv=sys.argv):
         decls += "\n    {NULL, 0, NULL, 0}\n};\n"
 
     comment_header = ""
+    env_comment = os.environ.get("DUCKARGS_COMMENT", 1)
+    try:
+        env_comment_int = int(env_comment)
+    except ValueError:
+        raise RuntimeError("DUCKARGS_COMMENT must be an integer")
+
+    if env_comment_int > 0:
+        comment_header = (f"// Generated by duckargs, invoked with the following arguments:\n// " +
+                          ' '.join(argv[1:]) + "\n\n")
+
+    CmdlineOpt.positional_count = 0
 
     if has_flags:
         comment_header += "#include <stdbool.h>\n"