#include "EterLib/StdAfx.h"
#include "UIRenderCommands.h"
#include "RenderCommands3D.h"
#include "EterLib/StateManager.h"

#include <algorithm>

namespace {
struct Point { float x, y; };
std::vector<Point> clip_polygon(std::vector<Point> polygon, int edge, float bound) {
    std::vector<Point> result;
    if (polygon.empty()) return result;
    auto inside = [edge, bound](Point p) {
        return edge == 0 ? p.x >= bound : edge == 1 ? p.x <= bound
             : edge == 2 ? p.y >= bound : p.y <= bound;
    };
    auto intersect = [edge, bound](Point a, Point b) {
        const float t = edge < 2 ? (bound - a.x) / (b.x - a.x)
                                 : (bound - a.y) / (b.y - a.y);
        return Point{a.x + t * (b.x - a.x), a.y + t * (b.y - a.y)};
    };
    Point previous = polygon.back();
    for (Point current : polygon) {
        const bool was_inside = inside(previous), is_inside = inside(current);
        if (was_inside != is_inside) result.push_back(intersect(previous, current));
        if (is_inside) result.push_back(current);
        previous = current;
    }
    return result;
}
std::vector<UIRenderCommand> commands;
std::uint64_t frame_id = 0;
int canvas_width = 0;
int canvas_height = 0;
float clip_x1 = 0, clip_y1 = 0, clip_x2 = 0, clip_y2 = 0;
float saved_x1 = 0, saved_y1 = 0, saved_x2 = 0, saved_y2 = 0;
float offset_x = 0;
}

void UIRenderSetOffsetX(float x) { offset_x = x; }
float UIRenderOffsetX() { return offset_x; }

void UIRenderSetSize(int width, int height) { canvas_width = width; canvas_height = height; }
void UIRenderGetSize(unsigned* width, unsigned* height) {
    if (width) *width = canvas_width;
    if (height) *height = canvas_height;
}
void UIRenderBeginFrame() {
    ++frame_id;
    commands.clear();
    clip_x1 = clip_y1 = 0;
    clip_x2 = canvas_width;
    clip_y2 = canvas_height;
}
std::uint64_t UIRenderFrameId() { return frame_id; }
void UIRenderAdd(UIRenderCommand command) {
    if (offset_x != 0) {
        command.x1 += offset_x;
        command.x2 += offset_x;
        if (command.quad)
            for (float& x : command.qx) x += offset_x;
    }
    command.clip_x1 = clip_x1; command.clip_y1 = clip_y1;
    command.clip_x2 = clip_x2; command.clip_y2 = clip_y2;
    command.behind_3d = Render3DDraws().empty();
    if (command.kind == UIRenderCommand::Bar && command.quad) {
        // Cooldown fans are triangles. Clip their geometry before either renderer consumes it.
        std::vector<Point> polygon{{command.qx[0], command.qy[0]},
                                   {command.qx[1], command.qy[1]},
                                   {command.qx[2], command.qy[2]}};
        const float bounds[4] = {clip_x1, clip_x2, clip_y1, clip_y2};
        for (int edge = 0; edge < 4; ++edge)
            polygon = clip_polygon(std::move(polygon), edge, bounds[edge]);
        for (std::size_t i = 1; i + 1 < polygon.size(); ++i) {
            UIRenderCommand piece = command;
            const Point tri[3] = {polygon[0], polygon[i], polygon[i + 1]};
            const float area = (tri[1].x - tri[0].x) * (tri[2].y - tri[0].y) -
                               (tri[1].y - tri[0].y) * (tri[2].x - tri[0].x);
            if (area == 0.0f) continue;
            for (int k = 0; k < 4; ++k) {
                piece.qx[k] = tri[k < 3 ? k : 2].x;
                piece.qy[k] = tri[k < 3 ? k : 2].y;
            }
            piece.x1 = std::min({tri[0].x, tri[1].x, tri[2].x});
            piece.y1 = std::min({tri[0].y, tri[1].y, tri[2].y});
            piece.x2 = std::max({tri[0].x, tri[1].x, tri[2].x});
            piece.y2 = std::max({tri[0].y, tri[1].y, tri[2].y});
            commands.push_back(std::move(piece));
        }
        return;
    }
    commands.push_back(command);
}
const std::vector<UIRenderCommand>& UIRenderCommands() { return commands; }
void UIRenderSetClip(float x, float y, float width, float height) {
    saved_x1 = clip_x1; saved_y1 = clip_y1; saved_x2 = clip_x2; saved_y2 = clip_y2;
    clip_x1 = x + offset_x; clip_y1 = y;
    clip_x2 = x + offset_x + width; clip_y2 = y + height;
}
void UIRenderRestoreClip() {
    clip_x1 = saved_x1; clip_y1 = saved_y1;
    clip_x2 = saved_x2; clip_y2 = saved_y2;
}

void UIRenderAddImage(const CGraphicTexture* texture, const float x[4], const float y[4],
                      float su, float sv, float eu, float ev, std::uint32_t argb, int blend) {
    UIRenderAddImageNamed(UIRenderTextureName(texture), x, y, su, sv, eu, ev, argb, blend);
}

void UIRenderAddImageNamed(const std::string& texture_name, const float x[4], const float y[4],
                           float su, float sv, float eu, float ev, std::uint32_t argb, int blend) {
    // 40250 draws the image quad through the device: the UI pass's world transform places it
    // (identity except where a caller sets one, e.g. CPythonMiniMap::RenderAtlas's window offset) and a
    // stage-0 MODULATE with D3DTA_TFACTOR tints it (the atlas's NPC/warp/waypoint marks).
    D3DXMATRIX world;
    D3DXMatrixIdentity(&world);
    if (CStateManager* state = CStateManager::InstancePtr()) {
        state->GetTransform(D3DTS_WORLD, &world);
        DWORD op = 0, arg1 = 0, arg2 = 0;
        state->GetTextureStageState(0, D3DTSS_COLOROP, &op);
        state->GetTextureStageState(0, D3DTSS_COLORARG1, &arg1);
        state->GetTextureStageState(0, D3DTSS_COLORARG2, &arg2);
        if (op == D3DTOP_MODULATE && (arg1 == D3DTA_TFACTOR || arg2 == D3DTA_TFACTOR)) {
            // TFACTOR x TEXTURE drops the vertex colour; TFACTOR x DIFFUSE scales it. The canvas
            // multiplies the texture in.
            const std::uint32_t factor = state->GetRenderState(D3DRS_TEXTUREFACTOR) & 0x00FFFFFFu;
            const DWORD other = arg1 == D3DTA_TFACTOR ? arg2 : arg1;
            if (other == D3DTA_DIFFUSE) {
                std::uint32_t tinted = argb & 0xFF000000u;
                for (int shift = 0; shift < 24; shift += 8)
                    tinted |= ((((argb >> shift) & 255) * ((factor >> shift) & 255) + 127) / 255) << shift;
                argb = tinted;
            } else {
                argb = (argb & 0xFF000000u) | factor;
            }
        }
    }
    UIRenderCommand command{UIRenderCommand::Image, 0, 0, 0, 0, argb};
    for (int i = 0; i < 4; ++i) {
        command.qx[i] = x[i] * world._11 + y[i] * world._21 + world._41 + 0.5f;
        command.qy[i] = x[i] * world._12 + y[i] * world._22 + world._42 + 0.5f;
    }
    command.x1 = std::min({command.qx[0], command.qx[1], command.qx[2], command.qx[3]});
    command.y1 = std::min({command.qy[0], command.qy[1], command.qy[2], command.qy[3]});
    command.x2 = std::max({command.qx[0], command.qx[1], command.qx[2], command.qx[3]});
    command.y2 = std::max({command.qy[0], command.qy[1], command.qy[2], command.qy[3]});
    command.text = texture_name;
    command.quad = true;
    command.su = su; command.sv = sv; command.eu = eu; command.ev = ev;
    command.blend = blend;
    UIRenderAdd(std::move(command));
}