// SPDX-License-Identifier: Apache-2.0
// C++ stream-style wrappers for Rust logging FFI

#pragma once

// This header expects `rust_backend_ffi.h` to have been included first
// so that `RustLogLevel` and `rust_log_event_with_level` are available.

#include <sstream>
#include <string>
#include <ostream>

class RustLogStream {
public:
    explicit RustLogStream(RustLogLevel level) noexcept : level_(level) {}

    // Generic stream insertion
    template<typename T>
    RustLogStream& operator<<(const T& v) {
        try {
            oss_ << v;
        } catch (...) {
            // swallow; avoid exceptions crossing FFI
        }
        return *this;
    }

    // Support manipulators like std::endl
    RustLogStream& operator<<(std::ostream& (*manip)(std::ostream&)) {
        try {
            manip(oss_);
        } catch (...) {
        }
        return *this;
    }

    // Destructor emits buffered message
    ~RustLogStream() noexcept {
        try {
            const std::string s = oss_.str();
            if (!s.empty()) {
                rust_log_event_with_level(s.c_str(), level_);
            }
        } catch (...) {
            // never throw
        }
    }

    // Non-copyable
    RustLogStream(const RustLogStream&) = delete;
    RustLogStream& operator=(const RustLogStream&) = delete;

    // Movable
    RustLogStream(RustLogStream&&) = default;
    RustLogStream& operator=(RustLogStream&&) = default;

private:
    RustLogLevel level_;
    std::ostringstream oss_;
};

// Factories and macros
inline RustLogStream rust_log_info_stream() { return RustLogStream(RUST_LOG_LEVEL_INFO); }
inline RustLogStream rust_log_warn_stream() { return RustLogStream(RUST_LOG_LEVEL_WARN); }
inline RustLogStream rust_log_error_stream() { return RustLogStream(RUST_LOG_LEVEL_ERROR); }
inline RustLogStream rust_log_debug_stream() { return RustLogStream(RUST_LOG_LEVEL_DEBUG); }
inline RustLogStream rust_log_trace_stream() { return RustLogStream(RUST_LOG_LEVEL_TRACE); }
inline RustLogStream rust_log_fatal_stream() { return RustLogStream(RUST_LOG_LEVEL_FATAL); }

#define RUST_COUT() rust_log_info_stream()
#define RUST_CERR() rust_log_error_stream()
#define RUST_CDEBUG() rust_log_debug_stream()

// Usage example:
// RUST_COUT() << "User=" << user << " logged in" << std::endl;