#include "StatBar.h"

#include <algorithm>
#include <cmath>

#include "Gui.h"

static constexpr float BAR_BORDER = 3.0f;
static constexpr float LABEL_HEIGHT = 26.0f;
static constexpr float LABEL_GAP = 2.0f;
static constexpr float TRAIL_DELAY = 0.45f;         // seconds the lost amount lingers before draining
static constexpr float TRAIL_DRAIN_SPEED = 0.6f;    // of the whole bar a second
static constexpr float FLASH_TIME = 0.35f;

static const glm::vec3 BACKGROUND_COLOR(0.03f, 0.04f, 0.06f);
static const glm::vec3 HURT_BACKGROUND_COLOR(0.45f, 0.06f, 0.05f);
static const glm::vec3 TRAIL_COLOR(0.98f, 0.92f, 0.80f);
static const glm::vec3 DIMMED_COLOR(0.38f, 0.40f, 0.44f);
static const glm::vec3 TEXT_COLOR(0.95f, 0.97f, 1.0f);

// Drawn from images: the empty part is the fill image darkened, the lost part the fill image brightened
static const glm::vec3 IMAGE_EMPTY_TINT(0.16f, 0.13f, 0.13f);
static const glm::vec3 IMAGE_HURT_TINT(0.55f, 0.18f, 0.16f);
static const glm::vec3 IMAGE_TRAIL_TINT(2.2f, 1.9f, 1.7f);

static ImageBox* MakeImage(Texture* texture) {
    ImageBox* image = new ImageBox();
    image->surface = SurfaceTexture::Stretched(texture);
    image->Opacity = 0.0f;
    image->BindToRenderSystem();
    return image;
}

static Box* MakeBox(const glm::vec3& color) {
    Box* box = new Box();
    box->Color = color;
    box->Opacity = 0.0f;
    box->BindToRenderSystem();
    return box;
}

StatBar::StatBar(Font* font, const Style& newStyle) : style(newStyle) {
    if (Images()) {
        background = MakeImage(style.fillImage);
        trail = MakeImage(style.fillImage);
        fill = MakeImage(style.fillImage);
        if (style.frameImage)
            frame = MakeImage(style.frameImage);
    }
    else {
        background = MakeBox(BACKGROUND_COLOR);
        background->rounding = 0.5f;
        trail = MakeBox(TRAIL_COLOR);
        fill = MakeBox(style.fillColor);
    }

    label = new TextBox();
    label->font = font;
    label->fontsize = style.labelSize;
    label->Color = TEXT_COLOR;
    label->Opacity = 0.0f;
    label->textCenter = { 0.0f, 1.0f };
    label->BindToRenderSystem();
}

float StatBar::GetHeight() const {
    return LABEL_HEIGHT + LABEL_GAP + style.height;
}

void StatBar::Update(float dt, float opacity, float target, const std::string& text, const glm::vec2& position,
    bool reset, bool dimmed) {
    target = glm::clamp(target, 0.0f, 1.0f);
    if (reset) {
        fraction = trailFraction = target;
        flash = 0.0f;
        trailWait = 0.0f;
    }

    if (style.showLoss && target < fraction - 0.0001f) {
        flash = 1.0f;
        trailWait = TRAIL_DELAY;
    }
    fraction = target;

    if (style.showLoss) {
        trailWait -= dt;
        if (trailWait <= 0.0f)
            trailFraction = std::max(trailFraction - TRAIL_DRAIN_SPEED * dt, fraction);
        trailFraction = std::max(trailFraction, fraction);   // filling back up doesn't leave a trail
    }
    else {
        trailFraction = fraction;
    }
    flash = std::max(flash - dt / FLASH_TIME, 0.0f);
    dim += ((dimmed ? 1.0f : 0.0f) - dim) * (1.0f - std::exp(-10.0f * dt));

    const glm::vec2 barTopLeft = glm::round(position + glm::vec2(0.0f, LABEL_HEIGHT + LABEL_GAP));

    label->text = text;
    label->t2d.position = { 0.0f, 0.0f, std::round(position.x + 2.0f), std::round(position.y) };
    label->t2d.size = { 0.0f, 0.0f, style.width, LABEL_HEIGHT };
    label->Opacity = text.empty() ? 0.0f : opacity;

    // The fill color all the way down to lowFraction, then turning to lowColor
    const float low = 1.0f - glm::clamp(fraction / std::max(style.lowFraction, 0.0001f), 0.0f, 1.0f);
    glm::vec3 color = glm::mix(style.fillColor, style.lowColor, low);
    color = glm::mix(color, DIMMED_COLOR, dim);
    color = glm::mix(color, glm::vec3(1.0f), flash * 0.5f);

    if (Images()) {
        // Every layer covers the whole bar, the trail and fill cropped from the left to how much they show
        auto Place = [&](Box* box, float shown) {
            box->t2d.position = { 0.0f, 0.0f, barTopLeft.x, barTopLeft.y };
            box->t2d.size = { 0.0f, 0.0f, std::round(style.width * shown), style.height };
            static_cast<ImageBox*>(box)->crop = glm::vec2(shown, 1.0f);
        };
        Place(background, 1.0f);
        background->Color = glm::mix(IMAGE_EMPTY_TINT, IMAGE_HURT_TINT, flash);
        background->Opacity = opacity * 0.9f;

        Place(trail, trailFraction);
        trail->Color = IMAGE_TRAIL_TINT;
        trail->Opacity = trailFraction > fraction ? opacity : 0.0f;

        Place(fill, fraction);
        fill->Color = color;
        fill->Opacity = fraction > 0.0f ? opacity : 0.0f;

        if (frame) {
            Place(frame, 1.0f);
            frame->Opacity = opacity;
        }
        return;
    }

    const float inner = style.width - BAR_BORDER * 2.0f;
    const float innerHeight = style.height - BAR_BORDER * 2.0f;

    background->t2d.position = { 0.0f, 0.0f, barTopLeft.x, barTopLeft.y };
    background->t2d.size = { 0.0f, 0.0f, style.width, style.height };
    background->Color = glm::mix(BACKGROUND_COLOR, HURT_BACKGROUND_COLOR, flash);
    background->Opacity = opacity * 0.8f;

    trail->t2d.position = { 0.0f, 0.0f, barTopLeft.x + BAR_BORDER, barTopLeft.y + BAR_BORDER };
    trail->t2d.size = { 0.0f, 0.0f, std::round(inner * trailFraction), innerHeight };
    trail->Opacity = opacity * 0.85f;

    fill->t2d.position = { 0.0f, 0.0f, barTopLeft.x + BAR_BORDER, barTopLeft.y + BAR_BORDER };
    fill->t2d.size = { 0.0f, 0.0f, std::round(inner * fraction), innerHeight };
    fill->Color = color;
    fill->Opacity = opacity;
}