/*
 * Copyright (C) 2014 Aaron Seigo <aseigo@kde.org>
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the
 *   Free Software Foundation, Inc.,
 *   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA.
 */

#include <QDebug>
#include <QObject> // tr()
#include <QSet>
#include <QTextStream>

#include "state.h"
#include "syntaxtree.h"
#include "utils.h"
#include "common/log.h"

namespace CoreSyntax
{

bool exit(const QStringList &, State &)
{
    ::exit(0);
}

bool showHelp(const QStringList &commands, State &state)
{
    SyntaxTree::Command command = SyntaxTree::self()->match(commands);
    if (commands.isEmpty()) {
        state.printLine(QObject::tr("Welcome to the Sink command line tool!"));
        state.printLine(QObject::tr("Top-level commands:"));

        QSet<QString> sorted;
        for (auto syntax: SyntaxTree::self()->syntax()) {
            sorted.insert(syntax.keyword);
        }

        for (auto keyword: sorted) {
            state.printLine(keyword, 1);
        }
    } else if (const Syntax *syntax = command.first) {
        //TODO: get parent!
        state.print(QObject::tr("Command `%1`").arg(syntax->keyword));

        if (!syntax->help.isEmpty()) {
            state.print(": " + syntax->help);
        }
        state.printLine(QString("\n\n") + syntax->usage());
    } else {
        state.printError("Unknown command: " + commands.join(" "));
    }

    return true;
}

QStringList showHelpCompleter(const QStringList &commands, const QString &fragment, State &)
{
    QStringList items;

    for (auto syntax: SyntaxTree::self()->syntax()) {
        if (syntax.keyword != QObject::tr("help") &&
            (fragment.isEmpty() || syntax.keyword.startsWith(fragment))) {
            items << syntax.keyword;
        }
    }

    qSort(items);
    return items;
}

bool setDebugLevel(const QStringList &commands, State &state)
{
    if (commands.count() != 1) {
        state.printError(QObject::tr("Wrong number of arguments; expected 1 got %1").arg(commands.count()));
        return false;
    }

    bool ok = false;
    int level = commands[0].toUInt(&ok);

    if (!ok) {
        state.printError(QObject::tr("Expected a number between 0 and 6, got %1").arg(commands[0]));
        return false;
    }

    state.setDebugLevel(level);
    return true;
}

bool printDebugLevel(const QStringList &, State &state)
{
    state.printLine(QString::number(state.debugLevel()));
    return true;
}

bool printCommandTiming(const QStringList &, State &state)
{
    state.printLine(state.commandTiming() ? QObject::tr("on") : QObject::tr("off"));
    return true;
}

void printSyntaxBranch(State &state, const Syntax::List &list, int depth)
{
    if (list.isEmpty()) {
        return;
    }

    if (depth > 0) {
        state.printLine("\\", depth);
    }

    for (auto syntax: list) {
        state.print("|-", depth);
        state.printLine(syntax.keyword);
        printSyntaxBranch(state, syntax.children, depth + 1);
    }
}

bool printSyntaxTree(const QStringList &, State &state)
{
    printSyntaxBranch(state, SyntaxTree::self()->syntax(), 0);
    return true;
}

bool setLoggingLevel(const QStringList &commands, State &state)
{
    if (commands.count() != 1) {
        state.printError(QObject::tr("Wrong number of arguments; expected 1 got %1").arg(commands.count()));
        return false;
    }

    state.setLoggingLevel(commands.at(0));
    return true;
}

bool printLoggingLevel(const QStringList &commands, State &state)
{
    const QString level = state.loggingLevel();
    state.printLine(level);
    return true;
}

bool setLoggingAreas(const QStringList &commands, State &state)
{
    if (commands.isEmpty()) {
        state.printError(QObject::tr("Wrong number of arguments; expected logging areas."));
        return false;
    }

    QByteArrayList areas;
    for (const auto &c : commands) {
        areas << c.toLatin1();
    }

    Sink::Log::setDebugOutputFilter(Sink::Log::Area, areas);
    return true;
}

bool setLoggingFilter(const QStringList &commands, State &state)
{
    if (commands.isEmpty()) {
        state.printError(QObject::tr("Wrong number of arguments; expected resource identifier or application names."));
        return false;
    }

    QByteArrayList filter;
    for (const auto &c : commands) {
        filter << c.toLatin1();
    }

    Sink::Log::setDebugOutputFilter(Sink::Log::ApplicationName, filter);
    return true;
}

bool setLoggingFields(const QStringList &commands, State &state)
{
    QByteArrayList output;
    for (const auto &c : commands) {
        output << c.toLatin1();
    }

    Sink::Log::setDebugOutputFields(output);
    return true;
}

Syntax::List syntax()
{
    Syntax::List syntax;
    syntax << Syntax("exit", QObject::tr("Exits the application. Ctrl-d also works!"), &CoreSyntax::exit);

    Syntax help("help", QObject::tr("Print command information: help [command]"), &CoreSyntax::showHelp);
    help.completer = &CoreSyntax::showHelpCompleter;
    syntax << help;

    syntax << Syntax("syntaxtree", QString(), &printSyntaxTree);

    Syntax set("set", QObject::tr("Sets settings for the session"));
    set.children << Syntax("debug", QObject::tr("Set the debug level from 0 to 6"), &CoreSyntax::setDebugLevel);

    Syntax setTiming = Syntax("timing", QObject::tr("Whether or not to print the time commands take to complete"));
    setTiming.children << Syntax("on", QString(), [](const QStringList &, State &state) -> bool { state.setCommandTiming(true); return true; });
    setTiming.children << Syntax("off", QString(), [](const QStringList &, State &state) -> bool { state.setCommandTiming(false); return true; });
    set.children << setTiming;

    Syntax logging("logging", QObject::tr("Set the logging level to one of Trace, Log, Warning or Error"), &CoreSyntax::setLoggingLevel);
    logging.completer = [](const QStringList &, const QString &fragment, State &state) -> QStringList { return Utils::filteredCompletions(QStringList() << "trace" << "log" << "warning" << "error", fragment, Qt::CaseInsensitive); };
    set.children << logging;

    Syntax loggingAreas("loggingAreas", QObject::tr("Set logging areas."), &CoreSyntax::setLoggingAreas);
    set.children << loggingAreas;

    Syntax loggingFilter("loggingFilter", QObject::tr("Set logging filter."), &CoreSyntax::setLoggingFilter);
    set.children << loggingFilter;

    Syntax loggingFields("loggingFields", QObject::tr("Set logging fields."), &CoreSyntax::setLoggingFields);
    loggingFields.completer = [](const QStringList &, const QString &fragment, State &state) -> QStringList { return Utils::filteredCompletions(QStringList() << "name" << "function" << "location" << "", fragment, Qt::CaseInsensitive); };
    set.children << loggingFields;

    syntax << set;

    Syntax get("get", QObject::tr("Gets settings for the session"));
    get.children << Syntax("debug", QObject::tr("The current debug level from 0 to 6"), &CoreSyntax::printDebugLevel);
    get.children << Syntax("timing", QObject::tr("Whether or not to print the time commands take to complete"), &CoreSyntax::printCommandTiming);
    get.children << Syntax("logging", QObject::tr("The current logging level"), &CoreSyntax::printLoggingLevel);
    syntax << get;

    return syntax;
}

REGISTER_SYNTAX(CoreSyntax)

} // namespace CoreSyntax