// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.


// Copyright 2014 Tony Wasserka
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above copyright
//       notice, this list of conditions and the following disclaimer in the
//       documentation and/or other materials provided with the distribution.
//     * Neither the name of the owner nor the names of its contributors may
//       be used to endorse or promote products derived from this software
//       without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include <cstdlib>
#include <QLineEdit>
#include <QRegExpValidator>

#include "common/assert.h"
#include "spinbox.h"

CSpinBox::CSpinBox(QWidget* parent) : QAbstractSpinBox(parent), min_value(-100), max_value(100), value(0), base(10), num_digits(0)
{
    // TODO: Might be nice to not immediately call the slot.
    //       Think of an address that is being replaced by a different one, in which case a lot
    //       invalid intermediate addresses would be read from during editing.
    connect(lineEdit(), SIGNAL(textEdited(QString)), this, SLOT(OnEditingFinished()));

    UpdateText();
}

void CSpinBox::SetValue(qint64 val)
{
    auto old_value = value;
    value = std::max(std::min(val, max_value), min_value);

    if (old_value != value) {
        UpdateText();
        emit ValueChanged(value);
    }
}

void CSpinBox::SetRange(qint64 min, qint64 max)
{
    min_value = min;
    max_value = max;

    SetValue(value);
    UpdateText();
}

void CSpinBox::stepBy(int steps)
{
    auto new_value = value;
    // Scale number of steps by the currently selected digit
    // TODO: Move this code elsewhere and enable it.
    // TODO: Support for num_digits==0, too
    // TODO: Support base!=16, too
    // TODO: Make the cursor not jump back to the end of the line...
    /*if (base == 16 && num_digits > 0) {
        int digit = num_digits - (lineEdit()->cursorPosition() - prefix.length()) - 1;
        digit = std::max(0, std::min(digit, num_digits - 1));
        steps <<= digit * 4;
    }*/

    // Increment "new_value" by "steps", and perform annoying overflow checks, too.
    if (steps < 0 && new_value + steps > new_value) {
        new_value = std::numeric_limits<qint64>::min();
    } else if (steps > 0 && new_value + steps < new_value) {
        new_value = std::numeric_limits<qint64>::max();
    } else {
        new_value += steps;
    }

    SetValue(new_value);
    UpdateText();
}

QAbstractSpinBox::StepEnabled CSpinBox::stepEnabled() const
{
    StepEnabled ret = StepNone;

    if (value > min_value)
        ret |= StepDownEnabled;

    if (value < max_value)
        ret |= StepUpEnabled;

    return ret;
}

void CSpinBox::SetBase(int base)
{
    this->base = base;

    UpdateText();
}

void CSpinBox::SetNumDigits(int num_digits)
{
    this->num_digits = num_digits;

    UpdateText();
}

void CSpinBox::SetPrefix(const QString& prefix)
{
    this->prefix = prefix;

    UpdateText();
}

void CSpinBox::SetSuffix(const QString& suffix)
{
    this->suffix = suffix;

    UpdateText();
}

static QString StringToInputMask(const QString& input) {
    QString mask = input;

    // ... replace any special characters by their escaped counterparts ...
    mask.replace("\\", "\\\\");
    mask.replace("A", "\\A");
    mask.replace("a", "\\a");
    mask.replace("N", "\\N");
    mask.replace("n", "\\n");
    mask.replace("X", "\\X");
    mask.replace("x", "\\x");
    mask.replace("9", "\\9");
    mask.replace("0", "\\0");
    mask.replace("D", "\\D");
    mask.replace("d", "\\d");
    mask.replace("#", "\\#");
    mask.replace("H", "\\H");
    mask.replace("h", "\\h");
    mask.replace("B", "\\B");
    mask.replace("b", "\\b");
    mask.replace(">", "\\>");
    mask.replace("<", "\\<");
    mask.replace("!", "\\!");

    return mask;
}

void CSpinBox::UpdateText()
{
    // If a fixed number of digits is used, we put the line edit in insertion mode by setting an
    // input mask.
    QString mask;
    if (num_digits != 0) {
        mask += StringToInputMask(prefix);

        // For base 10 and negative range, demand a single sign character
        if (HasSign())
            mask += "X"; // identified as "-" or "+" in the validator

        // Uppercase digits greater than 9.
        mask += ">";

        // The greatest signed 64-bit number has 19 decimal digits.
        // TODO: Could probably make this more generic with some logarithms.
        // For reference, unsigned 64-bit can have up to 20 decimal digits.
        int digits = (num_digits != 0) ? num_digits
                     : (base == 16) ? 16
                     : (base == 10) ? 19
                     : 0xFF; // fallback case...

        // Match num_digits digits
        // Digits irrelevant to the chosen number base are filtered in the validator
        mask += QString("H").repeated(std::max(num_digits, 1));

        // Switch off case conversion
        mask += "!";

        mask += StringToInputMask(suffix);
    }
    lineEdit()->setInputMask(mask);

    // Set new text without changing the cursor position. This will cause the cursor to briefly
    // appear at the end of the line and then to jump back to its original position. That's
    // a bit ugly, but better than having setText() move the cursor permanently all the time.
    int cursor_position = lineEdit()->cursorPosition();
    lineEdit()->setText(TextFromValue());
    lineEdit()->setCursorPosition(cursor_position);
}

QString CSpinBox::TextFromValue()
{
    return prefix
           + QString(HasSign() ? ((value < 0) ? "-" : "+") : "")
           + QString("%1").arg(std::abs(value), num_digits, base, QLatin1Char('0')).toUpper()
           + suffix;
}

qint64 CSpinBox::ValueFromText()
{
    unsigned strpos = prefix.length();

    QString num_string = text().mid(strpos, text().length() - strpos - suffix.length());
    return num_string.toLongLong(nullptr, base);
}

bool CSpinBox::HasSign() const
{
    return base == 10 && min_value < 0;
}

void CSpinBox::OnEditingFinished()
{
    // Only update for valid input
    QString input = lineEdit()->text();
    int pos = 0;
    if (QValidator::Acceptable == validate(input, pos))
        SetValue(ValueFromText());
}

QValidator::State CSpinBox::validate(QString& input, int& pos) const
{
    if (!prefix.isEmpty() && input.left(prefix.length()) != prefix)
        return QValidator::Invalid;

    int strpos = prefix.length();

    // Empty "numbers" allowed as intermediate values
    if (strpos >= input.length() - HasSign() - suffix.length())
        return QValidator::Intermediate;

    DEBUG_ASSERT(base <= 10 || base == 16);
    QString regexp;

    // Demand sign character for negative ranges
    if (HasSign())
        regexp += "[+\\-]";

    // Match digits corresponding to the chosen number base.
    regexp += QString("[0-%1").arg(std::min(base, 9));
    if (base == 16) {
        regexp += "a-fA-F";
    }
    regexp += "]";

    // Specify number of digits
    if (num_digits > 0) {
        regexp += QString("{%1}").arg(num_digits);
    } else {
        regexp += "+";
    }

    // Match string
    QRegExp num_regexp(regexp);
    int num_pos = strpos;
    QString sub_input = input.mid(strpos, input.length() - strpos - suffix.length());

    if (!num_regexp.exactMatch(sub_input) && num_regexp.matchedLength() == 0)
        return QValidator::Invalid;

    sub_input = sub_input.left(num_regexp.matchedLength());
    bool ok;
    qint64 val = sub_input.toLongLong(&ok, base);

    if (!ok)
        return QValidator::Invalid;

    // Outside boundaries => don't accept
    if (val < min_value || val > max_value)
        return QValidator::Invalid;

    // Make sure we are actually at the end of this string...
    strpos += num_regexp.matchedLength();

    if (!suffix.isEmpty() && input.mid(strpos) != suffix) {
        return QValidator::Invalid;
    } else {
        strpos += suffix.length();
    }

    if (strpos != input.length())
        return QValidator::Invalid;

    // At this point we can say for sure that the input is fine. Let's fix it up a bit though
    input.replace(num_pos, sub_input.length(), sub_input.toUpper());

    return QValidator::Acceptable;
}