#include "ProductConsolePanel.h"

#include <XCEditor/Foundation/UIEditorTheme.h>

#include <algorithm>
#include <cmath>

namespace XCEngine::UI::Editor::App {

namespace {

using ::XCEngine::UI::UIColor;
using ::XCEngine::UI::UIDrawList;
using ::XCEngine::UI::UIPoint;
using ::XCEngine::UI::UIRect;

constexpr std::string_view kConsolePanelId = "console";
constexpr float kPadding = 8.0f;
constexpr float kLineHeight = 18.0f;
constexpr float kFontSize = 11.0f;

constexpr UIColor kSurfaceColor(0.205f, 0.205f, 0.205f, 1.0f);
constexpr UIColor kTextColor(0.840f, 0.840f, 0.840f, 1.0f);
constexpr UIColor kChannelColor(0.640f, 0.640f, 0.640f, 1.0f);
constexpr UIColor kEmptyColor(0.580f, 0.580f, 0.580f, 1.0f);

float ResolveTextTop(float rectY, float rectHeight, float fontSize) {
    const float lineHeight = fontSize * 1.6f;
    return rectY + std::floor((rectHeight - lineHeight) * 0.5f);
}

} // namespace

const UIEditorPanelContentHostPanelState* ProductConsolePanel::FindMountedConsolePanel(
    const UIEditorPanelContentHostFrame& contentHostFrame) const {
    for (const UIEditorPanelContentHostPanelState& panelState : contentHostFrame.panelStates) {
        if (panelState.panelId == kConsolePanelId && panelState.mounted) {
            return &panelState;
        }
    }

    return nullptr;
}

void ProductConsolePanel::Update(
    const ProductEditorSession& session,
    const UIEditorPanelContentHostFrame& contentHostFrame) {
    const UIEditorPanelContentHostPanelState* panelState =
        FindMountedConsolePanel(contentHostFrame);
    if (panelState == nullptr) {
        m_visible = false;
        m_bounds = {};
        m_entries = nullptr;
        return;
    }

    m_visible = true;
    m_bounds = panelState->bounds;
    m_entries = &session.consoleEntries;
}

void ProductConsolePanel::Append(UIDrawList& drawList) const {
    if (!m_visible || m_bounds.width <= 0.0f || m_bounds.height <= 0.0f) {
        return;
    }

    drawList.AddFilledRect(m_bounds, kSurfaceColor);

    const UIRect contentRect(
        m_bounds.x + kPadding,
        m_bounds.y + kPadding,
        (std::max)(m_bounds.width - kPadding * 2.0f, 0.0f),
        (std::max)(m_bounds.height - kPadding * 2.0f, 0.0f));

    if (m_entries == nullptr || m_entries->empty()) {
        drawList.AddText(
            UIPoint(contentRect.x, ResolveTextTop(contentRect.y, kLineHeight, kFontSize)),
            "Console is empty.",
            kEmptyColor,
            kFontSize);
        return;
    }

    const std::size_t maxVisibleLines = (std::max)(
        static_cast<std::size_t>(1),
        static_cast<std::size_t>(contentRect.height / kLineHeight));
    const std::size_t entryCount = m_entries->size();
    const std::size_t firstVisible =
        entryCount > maxVisibleLines ? entryCount - maxVisibleLines : 0u;

    drawList.PushClipRect(contentRect);
    float nextY = contentRect.y;
    for (std::size_t index = firstVisible; index < entryCount; ++index) {
        const ProductEditorConsoleEntry& entry = (*m_entries)[index];
        const std::string line = entry.channel.empty()
            ? entry.message
            : "[" + entry.channel + "] " + entry.message;

        drawList.AddText(
            UIPoint(contentRect.x, ResolveTextTop(nextY, kLineHeight, kFontSize)),
            line,
            entry.channel.empty() ? kTextColor : kChannelColor,
            kFontSize);
        nextY += kLineHeight;
    }
    drawList.PopClipRect();
}

} // namespace XCEngine::UI::Editor::App