Start CMake modernization scaffold

tools/pano_cli/main.cpp

@@ -0,0 +1,113 @@
+#include "foundation/result.h"
+
+#include <charconv>
+#include <cstdint>
+#include <iostream>
+#include <string_view>
+
+namespace {
+
+struct DocumentArgs {
+    std::uint32_t width = 0;
+    std::uint32_t height = 0;
+    std::uint32_t layers = 1;
+};
+
+bool parse_u32(std::string_view text, std::uint32_t& value)
+{
+    const auto* begin = text.data();
+    const auto* end = text.data() + text.size();
+    const auto [ptr, ec] = std::from_chars(begin, end, value);
+    return ec == std::errc {} && ptr == end;
+}
+
+void print_error(std::string_view command, std::string_view message)
+{
+    std::cout << "{\"ok\":false,\"command\":\"" << command
+              << "\",\"error\":\"" << message << "\"}\n";
+}
+
+void print_help()
+{
+    std::cout
+        << "pano_cli commands:\n"
+        << "  create-document --width N --height N [--layers N]\n"
+        << "  --help\n";
+}
+
+pp::foundation::Status parse_document_args(int argc, char** argv, DocumentArgs& args)
+{
+    for (int i = 2; i < argc; ++i) {
+        const std::string_view key(argv[i]);
+        if (key == "--width" || key == "--height" || key == "--layers") {
+            if (i + 1 >= argc) {
+                return pp::foundation::Status::invalid_argument("missing value for option");
+            }
+
+            std::uint32_t value = 0;
+            if (!parse_u32(argv[++i], value)) {
+                return pp::foundation::Status::invalid_argument("option value must be an unsigned integer");
+            }
+
+            if (key == "--width") {
+                args.width = value;
+            } else if (key == "--height") {
+                args.height = value;
+            } else {
+                args.layers = value;
+            }
+        } else {
+            return pp::foundation::Status::invalid_argument("unknown option");
+        }
+    }
+
+    if (args.width == 0 || args.height == 0) {
+        return pp::foundation::Status::invalid_argument("width and height must be greater than zero");
+    }
+
+    if (args.layers == 0) {
+        return pp::foundation::Status::invalid_argument("layer count must be greater than zero");
+    }
+
+    return pp::foundation::Status::success();
+}
+
+int create_document(int argc, char** argv)
+{
+    DocumentArgs args;
+    const auto status = parse_document_args(argc, argv, args);
+    if (!status.ok()) {
+        print_error("create-document", status.message);
+        return 2;
+    }
+
+    std::cout << "{\"ok\":true,\"command\":\"create-document\",\"document\":{"
+              << "\"width\":" << args.width
+              << ",\"height\":" << args.height
+              << ",\"layers\":" << args.layers
+              << "}}\n";
+    return 0;
+}
+
+}
+
+int main(int argc, char** argv)
+{
+    if (argc < 2) {
+        print_help();
+        return 1;
+    }
+
+    const std::string_view command(argv[1]);
+    if (command == "--help" || command == "-h") {
+        print_help();
+        return 0;
+    }
+
+    if (command == "create-document") {
+        return create_document(argc, argv);
+    }
+
+    print_error(command, "unknown command");
+    return 2;
+}