#include "logging.hh"
#include "util.hh"

namespace nix {

Logger * logger = 0;

class SimpleLogger : public Logger
{
public:

    bool systemd, tty;

    SimpleLogger()
    {
        systemd = getEnv("IN_SYSTEMD") == "1";
        tty = isatty(STDERR_FILENO);
    }

    void log(Verbosity lvl, const FormatOrString & fs) override
    {
        if (lvl > verbosity) return;

        std::string prefix;

        if (systemd) {
            char c;
            switch (lvl) {
            case lvlError: c = '3'; break;
            case lvlInfo: c = '5'; break;
            case lvlTalkative: case lvlChatty: c = '6'; break;
            default: c = '7';
            }
            prefix = std::string("<") + c + ">";
        }

        writeToStderr(prefix + (tty ? fs.s : filterANSIEscapes(fs.s)) + "\n");
    }

    void startActivity(Activity & activity, Verbosity lvl, const FormatOrString & fs) override
    {
        log(lvl, fs);
    }

    void stopActivity(Activity & activity) override
    {
    }
};

Verbosity verbosity = lvlInfo;

void warnOnce(bool & haveWarned, const FormatOrString & fs)
{
    if (!haveWarned) {
        printMsg(lvlError, format("warning: %1%") % fs.s);
        haveWarned = true;
    }
}

void writeToStderr(const string & s)
{
    try {
        writeFull(STDERR_FILENO, s);
    } catch (SysError & e) {
        /* Ignore failing writes to stderr if we're in an exception
           handler, otherwise throw an exception.  We need to ignore
           write errors in exception handlers to ensure that cleanup
           code runs to completion if the other side of stderr has
           been closed unexpectedly. */
        if (!std::uncaught_exception()) throw;
    }
}

Logger * makeDefaultLogger()
{
    return new SimpleLogger();
}

}