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//
// Copyright (c) 2004-2021 musikcube team
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//////////////////////////////////////////////////////////////////////////////

#include <stdafx.h>
#include <cursespp/ScrollAdapterBase.h>
#include <cursespp/ScrollableWindow.h>
#include <cursespp/MultiLineEntry.h>
#include <cursespp/ListWindow.h>

using namespace cursespp;

typedef IScrollAdapter::EntryPtr EntryPtr;

ScrollAdapterBase::ScrollAdapterBase() {
    this->height = 0;
    this->width = 0;
}

ScrollAdapterBase::~ScrollAdapterBase() {

}

void ScrollAdapterBase::SetDisplaySize(size_t width, size_t height) {
    this->width = width;
    this->height = height;
}

size_t ScrollAdapterBase::GetLineCount() {
    return -1;
}

size_t ScrollAdapterBase::GetVisibleItems(
    cursespp::ScrollableWindow* window,
    size_t desiredTopIndex,
    std::deque<EntryPtr>& target)
{
    size_t actualTopIndex = desiredTopIndex;

    /* ensure we have enough data to draw from the specified position
    to the end. if we don't try to back up a bit until we can fill
    the buffer */
    int totalHeight = (int) this->height;
    int entryCount = (int) this->GetEntryCount();

    /* we assume the general case -- we're some where in the middle of the
    list. we'll start from the specified first item and work our way down */
    for (int i = (int) desiredTopIndex; i < entryCount && totalHeight > 0; i++) {
        EntryPtr entry = this->GetEntry(window, i);
        entry->SetWidth(this->width);
        totalHeight -= entry->GetLineCount();
        target.push_back(entry);
    }

    /* however, if the list is short, we can actually draw more items above
    the specified one. let's work our way backwards! */
    if (totalHeight > 0) {
        target.clear();

        totalHeight = this->height;
        int i = GetEntryCount() - 1;
        while (i >= 0 && totalHeight >= 0) {
            EntryPtr entry = this->GetEntry(window, i);
            entry->SetWidth(this->width);

            int lines = entry->GetLineCount();
            if (lines > totalHeight) {
                break; /* this Entry won't fit. bail. */
            }

            totalHeight -= lines;
            target.push_front(entry);
            --i;
        }

        actualTopIndex = i + 1;
    }

    return actualTopIndex;
}

void ScrollAdapterBase::DrawPage(ScrollableWindow* scrollable, size_t index, ScrollPosition& result) {
    WINDOW* window = scrollable->GetContent();

    if (!scrollable->IsVisible() || !window || this->height == 0 || this->width == 0) {
        return;
    }

    werase(window);

    std::deque<EntryPtr> visible;
    size_t drawnLines = 0;
    size_t topIndex = 0;
    size_t count = GetEntryCount();

    if (count > 0) {
        if (index >= count) {
            index = count - 1;
        }

        topIndex = GetVisibleItems(scrollable, index, visible);

        for (size_t e = 0; e < visible.size(); e++) {
            EntryPtr entry = visible.at(e);
            size_t count = entry->GetLineCount();
            wmove(window, drawnLines, 0);

            for (size_t i = 0; i < count && drawnLines < this->height; i++) {
                Color attrs = Color::Default;

                if (this->decorator) {
                    attrs = this->decorator(scrollable, topIndex + e, i, entry);
                }

                if (attrs == -1) {
                    attrs = entry->GetAttrs(i);
                }

                if (attrs != -1) {
                    wattron(window, attrs);
                }

                std::string line = entry->GetLine(i);
                size_t len = u8cols(line);

                /* pad with empty spaces to the end of the line. this allows us to
                do highlight rows. this should probably be configurable. */

                int remain = this->width - len;
                if (remain > 0) {
                    line += std::string(remain, ' ');
                }

                /* string is padded above, we don't need a \n */
                checked_wprintw(window, "%s", line.c_str());

                if (attrs != -1) {
                    wattroff(window, attrs);
                }

                ++drawnLines;
            }
        }
    }

    result.visibleEntryCount = visible.size();
    result.firstVisibleEntryIndex = topIndex;
    result.lineCount = drawnLines;
    result.totalEntries = count;
}
