#include "messagedelegate.h"
#include "chatview.h"
#include "debug_ui.h"
#include "emoji.h"
#include "animtimer.h"
#include "lottieicon.h"
#include <cmath>
#include <QPainter>
#include <QPainterPath>
#include <QApplication>
#include <QAbstractItemView>
#include <QFontMetrics>
#include <QTextLayout>

MessageDelegate::MessageDelegate(QObject *parent)
    : QStyledItemDelegate(parent) {}

QSize MessageDelegate::sizeHint(const QStyleOptionViewItem &option,
                                const QModelIndex &index) const {
    Layout L = calcLayout(option, index);
    return QSize(L.viewWidth, L.totalHeight);
}

static int measureTextHeight(const QFont &font, const QString &text, int width) {
    if (text.isEmpty() || width <= 0) return 0;
    QRect r = QFontMetrics(font).boundingRect(QRect(0, 0, width, 100000),
                                               Qt::AlignLeft | Qt::TextWordWrap, text);
    return r.height();
}

static int calcMaxLineWidth(const QFont &font, const QString &text, int availW) {
    int maxW = 0;
    int pos = 0;
    while (pos <= text.length()) {
        int end = text.indexOf('\n', pos);
        if (end < 0) end = text.length();
        QString para = text.mid(pos, end - pos);
        if (!para.isEmpty()) {
            QTextLayout layout(para, font);
            layout.beginLayout();
            while (true) {
                QTextLine line = layout.createLine();
                if (!line.isValid()) break;
                line.setLineWidth(availW);
                line.setPosition(QPointF(0, 0));
                maxW = qMax(maxW, (int)line.naturalTextWidth());
            }
            layout.endLayout();
        }
        pos = end + 1;
    }
    return maxW;
}

MessageDelegate::Layout MessageDelegate::calcLayout(
    const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    Layout L{};
    L.viewWidth = 300;
    if (option.widget) {
        auto *v = qobject_cast<const QAbstractItemView *>(option.widget);
        if (v) L.viewWidth = v->viewport()->width();
    }
    if (L.viewWidth <= 0) L.viewWidth = 300;

    bool hasQuote = index.data(MsgHasQuoteRole).toBool();
    QString text  = index.data(MsgTextRole).toString();
    QString qText = hasQuote ? index.data(MsgQuoteTextRole).toString() : QString();

    int availW = L.viewWidth - kMarginH - kAvatar - kGap - kMarginH;
    L.narrow = (availW < 400);
    if (L.narrow) availW = L.viewWidth - 2 * kMarginH;
    int textLimitW = availW - 2 * kPadH;
    int limitW = text.contains(' ') ? qMin(textLimitW, 700)
                                    : qMin(textLimitW, 1200);

    QFontMetrics fm(option.font);
    int contentW = calcMaxLineWidth(option.font, text, limitW);

    QString author = index.data(MsgAuthorRole).toString();
    QFont boldFm = option.font;
    boldFm.setBold(true);
    int authorW = QFontMetrics(boldFm).horizontalAdvance(author);
    contentW = qMax(contentW, authorW);

    if (hasQuote) {
        QString qAuthor = index.data(MsgQuoteAuthorRole).toString();
        int qAuthorW = QFontMetrics(boldFm).horizontalAdvance(qAuthor);
        contentW = qMax(contentW, qAuthorW + kQuoteBarW + kQuotePadH + 4);
        int qTextW = qMin(contentW + 8, limitW);
        int qWidth = calcMaxLineWidth(option.font, qText, qTextW);
        contentW = qMax(contentW, qWidth + kQuoteBarW + kQuotePadH + 4);
    }

    int textW = qMax(200 - 2 * kPadH, contentW);
    textW = qMin(textW, textLimitW);
    int bubbleW = textW + 2 * kPadH;
    L.bubbleWidth = bubbleW;

    int qH = 0;
    if (hasQuote) {
        int qTextW = bubbleW - 2 * kPadH - kQuoteBarW - kQuotePadH;
        int qTextH = measureTextHeight(option.font, qText, qTextW);
        int qOneLineH = fm.height();
        qH = kQuotePadV + qOneLineH + (qText.isEmpty() ? 0 : 2 + qTextH) + kQuotePadV;
    }

    int textH = measureTextHeight(option.font, text, textW);
    int authorH = fm.height();
    int bubbleH = kPadTop + authorH + 2 + (hasQuote ? qH + kQuoteGap : 0) + textH + kStatusH + kPadBot;
    L.totalHeight = qMax(bubbleH, kAvatar) + kItemGap;

    int contentLeft = L.narrow ? kMarginH : (kMarginH + kAvatar + kGap);

    L.bubbleRect = QRect(contentLeft, 0, bubbleW, bubbleH);

    int contentTop = kPadTop;

    L.authorRect = QRect(contentLeft + kPadH, contentTop, textW, authorH);
    contentTop += authorH + 2;

    if (hasQuote) {
        L.quoteRect = QRect(contentLeft + kPadH, contentTop, bubbleW - 2 * kPadH, qH);
        L.quoteBarRect = QRect(L.quoteRect.left(), L.quoteRect.top(),
                               kQuoteBarW, qH);
        int tx = L.quoteBarRect.right() + kQuotePadH;
        L.quoteAuthorRect = QRect(tx, L.quoteRect.top() + kQuotePadV,
                                  L.quoteRect.width() - kQuoteBarW - kQuotePadH,
                                  QFontMetrics(option.font).height());
        L.quoteTextRect = QRect(tx,
                                L.quoteAuthorRect.bottom() + 2,
                                L.quoteAuthorRect.width(),
                                qH - kQuotePadV - QFontMetrics(option.font).height() - 2 - kQuotePadV);
        contentTop += qH + kQuoteGap;
    }

    L.textRect   = QRect(contentLeft + kPadH, contentTop,
                          textW, textH);
    L.statusRect = QRect(contentLeft + kPadH,
                          contentTop + textH + 2,
                          textW, kStatusH);

    if (!L.narrow) {
        int avatarY = L.bubbleRect.bottom() - kAvatar;
        L.avatarRect = QRect(kMarginH, avatarY, kAvatar, kAvatar);
    }

    return L;
}

static int paraLayoutHeight(const QFont &font, const QString &text,
                            int textWidth, int globalChar, qreal globalY,
                            int yTop, int yBot, int xTop, int xBot,
                            bool &foundStart, bool &foundEnd,
                            int &startChar, int &endChar) {
    if (text.isEmpty()) return QFontMetrics(font).lineSpacing();

    QTextLayout layout(text, font);
    layout.beginLayout();
    qreal localY = 0;
    while (true) {
        QTextLine line = layout.createLine();
        if (!line.isValid()) break;
        line.setLineWidth(textWidth);
        line.setPosition(QPointF(0, globalY + localY));
        localY += line.height();

        if (!foundStart && globalY + localY > yTop) {
            startChar = globalChar + line.xToCursor(xTop);
            foundStart = true;
        }
        if (!foundEnd && globalY >= yBot) break;
        if (!foundEnd && globalY + localY >= yBot) {
            endChar = globalChar + line.xToCursor(xBot);
            foundEnd = true;
        }
    }
    layout.endLayout();
    return (int)ceil(localY);
}

static void calcTextSelection(const QFont &font, const QString &text,
                               int textWidth, const QPoint &p1, const QPoint &p2,
                               int &startChar, int &endChar) {
    startChar = 0;
    endChar = 0;
    if (text.isEmpty() || textWidth <= 0) return;

    int yTop = qMin(p1.y(), p2.y());
    int yBot = qMax(p1.y(), p2.y());
    int xTop = (p1.y() < p2.y()) ? p1.x() : p2.x();
    int xBot = (p1.y() < p2.y()) ? p2.x() : p1.x();

    int globalChar = 0;
    qreal globalY = 0;
    bool foundStart = false, foundEnd = false;
    int paraStart = 0;

    while (paraStart <= text.length()) {
        int paraEnd = text.indexOf('\n', paraStart);
        if (paraEnd < 0) paraEnd = text.length();
        QString para = text.mid(paraStart, paraEnd - paraStart);

        int paraH = paraLayoutHeight(font, para, textWidth,
                                     globalChar, globalY,
                                     yTop, yBot, xTop, xBot,
                                     foundStart, foundEnd,
                                     startChar, endChar);
        globalChar += para.length();
        globalY += paraH;

        if (paraEnd < text.length())
            globalChar++;

        paraStart = paraEnd + 1;
        if (foundStart && foundEnd) break;
    }

    if (!foundStart) startChar = 0;
    if (!foundEnd) endChar = text.length();
    if (startChar == endChar && endChar < text.length()) endChar = startChar + 1;
    if (startChar > endChar) qSwap(startChar, endChar);
}

static void drawTextSelectionHighlight(QPainter *p, const QFont &font,
                                        const QString &text, int textWidth,
                                        const QRect &textRect,
                                        const QColor &selColor,
                                        int startChar, int endChar) {
    if (startChar >= endChar) return;

    int globalChar = 0;
    qreal globalY = 0;
    int paraStart = 0;

    while (paraStart <= text.length()) {
        int paraEnd = text.indexOf('\n', paraStart);
        if (paraEnd < 0) paraEnd = text.length();
        QString para = text.mid(paraStart, paraEnd - paraStart);

        if (para.isEmpty()) {
            globalY += QFontMetrics(font).lineSpacing();
        } else {
            QTextLayout layout(para, font);
            layout.beginLayout();
            qreal localY = 0;
            while (true) {
                QTextLine line = layout.createLine();
                if (!line.isValid()) break;
                line.setLineWidth(textWidth);
                line.setPosition(QPointF(0, globalY + localY));

                int ls = globalChar + line.textStart();
                int le = ls + line.textLength();
                localY += line.height();

                if (ls >= endChar || le <= startChar) continue;

                int cs = qMax(startChar, ls);
                int ce = qMin(endChar, le);

                qreal x1 = line.cursorToX(cs - globalChar);
                qreal x2 = line.cursorToX(ce - globalChar);

                QRectF hr(textRect.left() + x1,
                          textRect.top() + globalY + line.y(),
                          x2 - x1, line.height());
                p->fillRect(hr, selColor);
            }
            layout.endLayout();
            globalY += localY;
        }

        globalChar += para.length();
        if (paraEnd < text.length())
            globalChar++;

        paraStart = paraEnd + 1;
    }
}

static void drawAnimatedEmojiOverlay(QPainter *p, const QFont &font,
                                      const QString &text, int textWidth,
                                      const QRect &textRect) {
    if (g_animatedEmojiMap.isEmpty()) return;

    int globalChar = 0;
    qreal globalY = 0;
    int paraStart = 0;

    while (paraStart <= text.length()) {
        int paraEnd = text.indexOf('\n', paraStart);
        if (paraEnd < 0) paraEnd = text.length();
        QString para = text.mid(paraStart, paraEnd - paraStart);

        if (!para.isEmpty()) {
            QTextLayout layout(para, font);
            layout.beginLayout();
            qreal localY = 0;
            while (true) {
                QTextLine line = layout.createLine();
                if (!line.isValid()) break;
                line.setLineWidth((qreal)textWidth);
                line.setPosition(QPointF(0, globalY + localY));
                localY += line.height();

                int ls = globalChar + line.textStart();
                int le = ls + line.textLength();

                for (auto it = g_animatedEmojiMap.begin(); it != g_animatedEmojiMap.end(); ++it) {
                    const QString &unicode = it.key();
                    int pos = text.indexOf(unicode, ls);
                    while (pos >= 0 && pos + unicode.length() <= le) {
                        int linePos = pos - globalChar - line.textStart();
                        int cp1 = linePos, cp2 = linePos + unicode.length();
                        qreal x1 = line.cursorToX(&cp1);
                        qreal x2 = line.cursorToX(&cp2);

                        LottieIcon *icon = AnimTimer::instance()->icon(it.value());
                        if (icon && icon->isValid()) {
                            int eW = qMax(1, (int)((x2 - x1) * 1.3));
                            int eH = qMax(1, (int)(line.height() * 1.3));
                            QImage frame = icon->renderFrame(icon->currentFrame(), QSize(eW, eH));
                            qreal cx = x1 + (x2 - x1 - eW) * 0.5;
                            qreal cy = (line.height() - eH) * 0.5;
                            p->drawImage(QPointF(textRect.left() + cx, textRect.top() + line.y() + cy), frame);
                        }
                        pos = text.indexOf(unicode, pos + unicode.length());
                    }
                }
            }
            layout.endLayout();
            globalY += localY;
        } else {
            globalY += QFontMetrics(font).lineSpacing();
        }

        globalChar += para.length();
        if (paraEnd < text.length()) globalChar++;
        paraStart = paraEnd + 1;
    }
}

void MessageDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option,
                            const QModelIndex &index) const {
    painter->save();
    painter->translate(option.rect.topLeft());
    painter->setClipRect(QRect(QPoint(0, 0), option.rect.size()));

    Layout L = calcLayout(option, index);

    auto *cv = qobject_cast<const ChatView *>(option.widget);
    bool singleTextSel = false;
    bool multiRowSel   = false;
    if (cv && cv->hasSelection()) {
        if (cv->isRowSelected(index)) {
            if (cv->selStart() == cv->selEnd()) {
                singleTextSel = true;
            } else {
                multiRowSel = true;
            }
        }
    }

    drawBubble(painter, L);

    if (multiRowSel) {
        painter->save();
        painter->setPen(Qt::NoPen);
        painter->setBrush(QColor(0x33, 0x90, 0xEC, 40));
        painter->drawRect(L.bubbleRect);
        painter->restore();
    }

    if (index.data(MsgHasQuoteRole).toBool()) {
        drawQuote(painter, L, index, option);
    }

    if (!L.narrow)
        drawAvatar(painter, L, index);

    QFont authorFont = option.font;
    authorFont.setBold(true);
    painter->setFont(authorFont);
    painter->setPen(QColor(0x33, 0x90, 0xEC));
    painter->drawText(L.authorRect, Qt::AlignLeft | Qt::AlignVCenter,
                      index.data(MsgAuthorRole).toString());

    painter->setPen(option.palette.text().color());
    QFont textFont = option.font;
    textFont.setPointSize(textFont.pointSize());
    painter->setFont(textFont);

    QString msgText = index.data(MsgTextRole).toString();
    painter->drawText(L.textRect, Qt::AlignLeft | Qt::TextWordWrap, msgText);

    if (singleTextSel && cv) {
        const auto &ts = cv->textSelection();
        QPoint localP1(ts.clickPos.x() - L.textRect.left(),
                       ts.clickPos.y() - L.textRect.top());
        QPoint localP2(ts.dragPos.x() - L.textRect.left(),
                       ts.dragPos.y() - L.textRect.top());
        int startChar, endChar;
        calcTextSelection(textFont, msgText, L.textRect.width(),
                          localP1, localP2, startChar, endChar);
        const_cast<ChatView *>(cv)->setTextSelChars(startChar, endChar);
        drawTextSelectionHighlight(painter, textFont, msgText,
                                    L.textRect.width(), L.textRect,
                                    QColor(0x33, 0x90, 0xEC, 60),
                                    startChar, endChar);
    }

    drawAnimatedEmojiOverlay(painter, textFont, msgText,
                              L.textRect.width(), L.textRect);

    drawStatusBar(painter, L, index, option);

    painter->restore();
}

void MessageDelegate::drawQuote(QPainter *p, const Layout &L,
                                const QModelIndex &index,
                                const QStyleOptionViewItem &opt) const {
    p->save();

    p->setPen(Qt::NoPen);
    p->setBrush(QColor(0xFF, 0xEE, 0xEE));
    p->drawRoundedRect(L.quoteRect, 5, 5);

    p->setPen(Qt::NoPen);
    p->setBrush(QColor(0xE0, 0x40, 0x40));
    p->drawRect(L.quoteBarRect);

    QFont boldFont = opt.font;
    boldFont.setBold(true);
    p->setFont(boldFont);
    p->setPen(QColor(0xE0, 0x40, 0x40));
    p->drawText(L.quoteAuthorRect, Qt::AlignLeft | Qt::AlignVCenter,
                index.data(MsgQuoteAuthorRole).toString());

    p->setFont(opt.font);
    p->setPen(QColor(0x99, 0x55, 0x55));
    p->drawText(L.quoteTextRect, Qt::AlignLeft | Qt::TextWordWrap,
                index.data(MsgQuoteTextRole).toString());

    p->restore();
}

void MessageDelegate::drawBubble(QPainter *p, const Layout &L) const {
    p->save();
    p->setRenderHint(QPainter::Antialiasing);

    QRectF b = L.bubbleRect;
    qreal r = kRadius;
    qreal t = kTail;

    QPainterPath body;
    body.addRoundedRect(b, r, r);

    QPainterPath tail;
    qreal tx = b.left();
    qreal ty = b.bottom();
    tail.moveTo(tx, ty - r);
    tail.lineTo(tx - t, ty - t / 2.0);
    tail.lineTo(tx + r, ty);
    tail.closeSubpath();

    QPainterPath combined = body.united(tail);

    p->setPen(QPen(QColor(0xE0, 0xE0, 0xE0), 0.5));
    p->setBrush(QColor(255, 255, 255));
    p->drawPath(combined);

    p->restore();
}

void MessageDelegate::drawStatusBar(QPainter *p, const Layout &L,
                                    const QModelIndex &index,
                                    const QStyleOptionViewItem &opt) const {
    p->save();

    QRect r = L.statusRect;

    QVariant reactionsVar = index.data(MsgReactionsRole);
    QVariantList reactions = reactionsVar.toList();

    int rx = r.left();
    if (!reactions.isEmpty()) {
        for (const QVariant &rv : reactions) {
            QVariantMap rm = rv.toMap();
            QString emoji = rm["emoji"].toString();
            int count = rm["count"].toInt();
            QVariant colorsVar = rm["colors"];
            QList<QColor> colors = colorsVar.value<QList<QColor>>();

            if (count < 4 && !colors.isEmpty()) {
                int iconSize = 16;
                for (int i = colors.size() - 1; i >= 0; --i) {
                    int cx = rx + i * 11;
                    p->setPen(Qt::NoPen);
                    p->setBrush(colors[i]);
                    p->drawEllipse(cx, r.top() + 1, iconSize, iconSize);
                }
                rx += colors.size() * 11 + 8;
            } else {
                LottieIcon *rIcon = nullptr;
                if (g_animatedEmojiMap.contains(emoji))
                    rIcon = AnimTimer::instance()->icon(g_animatedEmojiMap[emoji]);

                if (rIcon && rIcon->isValid()) {
                    int iconSz = qMin((int)(20 * 1.3), r.height());
                    QImage frame = rIcon->renderFrame(rIcon->currentFrame(), QSize(iconSz, iconSz));
                    p->drawImage(rx, r.top() + (r.height() - iconSz) / 2, frame);
                    rx += iconSz + 2;
                } else {
                    QFont emojiFont = opt.font;
                    emojiFont.setPointSize(emojiFont.pointSize() - 1);
                    p->setFont(emojiFont);
                    p->setPen(opt.palette.text().color());
                    QRect emojiRect(rx, r.top(), 20, r.height());
                    p->drawText(emojiRect, Qt::AlignLeft | Qt::AlignVCenter, emoji);
                    rx += 20;
                }

                QFont countFont = opt.font;
                countFont.setPointSize(countFont.pointSize() - 2);
                p->setFont(countFont);
                p->setPen(QColor(0x80, 0x80, 0x80));
                QRect cntRect(rx, r.top(), 24, r.height());
                p->drawText(cntRect, Qt::AlignLeft | Qt::AlignVCenter,
                            QString::number(count));
                rx = cntRect.right() + 8;
            }
        }
    }

    QFont smallFont = opt.font;
    smallFont.setPointSize(smallFont.pointSize() - 2);
    p->setFont(smallFont);
    p->setPen(QColor(0x80, 0x80, 0x80));

    QString statusText;
    if (index.data(MsgEditedRole).toBool()) {
        statusText = QString::fromUtf8("изменено  ");
    }
    statusText += index.data(MsgTimeRole).toString();
    p->drawText(QRect(r.left(), r.top(), r.width(), r.height()),
                Qt::AlignRight | Qt::AlignVCenter, statusText);

    p->restore();
}

void MessageDelegate::drawAvatar(QPainter *p, const Layout &L,
                                 const QModelIndex &index) const {
    QPixmap av = index.data(MsgAvatarRole).value<QPixmap>();
    if (av.isNull()) return;

    p->save();
    p->setRenderHint(QPainter::Antialiasing);
    QPainterPath clip;
    clip.addEllipse(L.avatarRect);
    p->setClipPath(clip);
    p->drawPixmap(L.avatarRect, av);
    p->restore();
}