/*
Crafter®.Graphics
Copyright (C) 2026 Catcrafts®
catcrafts.net

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License version 3.0 as published by the Free Software Foundation;

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
*/

module;
#include "../lib/stb_truetype.h"
export module Crafter.Graphics:RenderingElement2D;
import Crafter.Asset;
import std;
import :Transform2D;
import :RenderingElement2DBase;
import :Font;
import :Types;
import :Window;

export namespace Crafter {
    template<bool Scaling, bool Owning, bool Rotating, std::uint8_t Alignment = 0, std::uint8_t Frames = 1> requires ((!Rotating || Scaling) && (!Owning || Scaling))
    struct RenderingElement2D : RenderingElement2DBase<Frames>, ScalingBase<Scaling, Owning, Alignment>, RotatingBase<Rotating> {
        RenderingElement2D() = default;
        RenderingElement2D(Anchor2D anchor, OpaqueType opaque) : RenderingElement2DBase<Frames>(anchor, opaque) {

        }
        RenderingElement2D(Anchor2D anchor, OpaqueType opaque, std::uint32_t rotation) requires(Rotating) : RenderingElement2DBase<Frames>(anchor, opaque), RotatingBase<Rotating>(rotation) {

        }
        RenderingElement2D(Anchor2D anchor, OpaqueType opaque, std::uint32_t bufferWidth, std::uint32_t bufferHeight, Vector<std::uint8_t, 4, Alignment>* scalingBuffer) requires(Scaling && !Owning) : RenderingElement2DBase<Frames>(anchor, opaque), ScalingBase<Scaling, Owning, Alignment>(bufferWidth, bufferHeight, scalingBuffer) {

        }
        RenderingElement2D(Anchor2D anchor, OpaqueType opaque, std::uint32_t bufferWidth, std::uint32_t bufferHeight, Vector<std::uint8_t, 4, Alignment>* scalingBuffer, std::uint32_t rotation) requires(Scaling && !Owning && Rotating) : RenderingElement2DBase<Frames>(anchor, opaque), ScalingBase<Scaling, Owning, Alignment>(bufferWidth, bufferHeight, scalingBuffer), RotatingBase<Rotating>(rotation) {

        }
        RenderingElement2D(Anchor2D anchor, OpaqueType opaque, std::uint32_t bufferWidth, std::uint32_t bufferHeight) requires(Owning) : RenderingElement2DBase<Frames>(anchor, opaque), ScalingBase<Scaling, Owning, Alignment>(bufferWidth, bufferHeight) {

        }
        RenderingElement2D(Anchor2D anchor, OpaqueType opaque, std::uint32_t bufferWidth, std::uint32_t bufferHeight, std::uint32_t rotation) requires(Owning && Rotating) : RenderingElement2DBase<Frames>(anchor, opaque), ScalingBase<Scaling, Owning, Alignment>(bufferWidth, bufferHeight) , RotatingBase<Rotating>(rotation) {

        }
        RenderingElement2D(Anchor2D anchor, TextureAsset<Vector<std::uint8_t, 4, Alignment>>& texture) requires(!Owning && Scaling) : RenderingElement2DBase<Frames>(anchor, texture.opaque), ScalingBase<Scaling, Owning, Alignment>(texture.pixels.data(), texture.sizeX, texture.sizeY) {

        }
        RenderingElement2D(Anchor2D anchor, TextureAsset<Vector<std::uint8_t, 4, Alignment>>& texture, std::uint32_t rotation) requires(!Owning && Scaling && Rotating) : RenderingElement2DBase<Frames>(anchor, texture.opaque), ScalingBase<Scaling, Owning, Alignment>(texture.pixels.data(), texture.sizeX, texture.sizeY), RotatingBase<Rotating>(rotation) {

        }

        RenderingElement2D(RenderingElement2D&) = delete;
        RenderingElement2D& operator=(RenderingElement2D&) = delete;

        void ScaleNearestNeighbor() requires(Scaling) {
            for (std::uint32_t y = 0; y < this->scaled.size.y; y++) {
                std::uint32_t srcY = y * ScalingBase<true, Owning, Alignment>::bufferHeight / this->scaled.size.y;
                for (std::uint32_t x = 0; x < this->scaled.size.x; x++) {
                    std::uint32_t srcX = x * ScalingBase<true, Owning, Alignment>::bufferWidth / this->scaled.size.x;
                    this->buffer[y * this->scaled.size.x + x] = ScalingBase<true, Owning, Alignment>::scalingBuffer[srcY * ScalingBase<true, Owning, Alignment>::bufferWidth + srcX];
                }
            }
        }

        void ScaleRotating() requires(Scaling) {
            const float dstWidth  = this->scaled.size.x;
            const float dstHeight = this->scaled.size.y;

            const float c2 = std::abs(std::cos(RotatingBase<true>::rotation));
            const float s2 = std::abs(std::sin(RotatingBase<true>::rotation));

            const float rotatedWidth  = dstWidth  * c2 + dstHeight * s2;
            const float rotatedHeight = dstWidth  * s2 + dstHeight * c2;

            const float diffX = std::ceil((rotatedWidth  - dstWidth)  * 0.5);
            const float diffY = std::ceil((rotatedHeight - dstHeight) * 0.5);

            this->scaled.size.x += diffX + diffX;
            this->scaled.size.y += diffY + diffY;

            this->scaled.position.x -= diffX;
            this->scaled.position.y -= diffY;

            this->buffer.clear();
            this->buffer.resize(this->scaled.size.x * this->scaled.size.y);

            // Destination center
            const float dstCx = (this->scaled.size.x  - 1.0) * 0.5;
            const float dstCy = (this->scaled.size.y - 1.0) * 0.5;

            // Source center
            const float srcCx = (ScalingBase<true, Owning, Alignment>::bufferWidth  - 1.0) * 0.5;
            const float srcCy = (ScalingBase<true, Owning, Alignment>::bufferHeight - 1.0) * 0.5;

            const float c = std::cos(RotatingBase<true>::rotation);
            const float s = std::sin(RotatingBase<true>::rotation);

            // Scale factors (destination → source)
            const float scaleX = static_cast<float>(ScalingBase<true, Owning, Alignment>::bufferWidth)  / dstWidth;
            const float scaleY = static_cast<float>(ScalingBase<true, Owning, Alignment>::bufferHeight) / dstHeight;

            for (std::uint32_t yB = 0; yB < this->scaled.size.y; ++yB) {
                for (std::uint32_t xB = 0; xB < this->scaled.size.x; ++xB) {

                    // ---- Destination pixel relative to center ----
                    const float dx = (static_cast<float>(xB) - dstCx) * scaleX;
                    const float dy = (static_cast<float>(yB) - dstCy) * scaleY;

                    // ---- Inverse rotation ----
                    const float sx =  (c * dx - s * dy) + srcCx;
                    const float sy =  (s * dx + c * dy) + srcCy;

                    // ---- Nearest neighbour sampling ----
                    const std::int32_t srcX = static_cast<std::int32_t>(std::round(sx));
                    const std::int32_t srcY = static_cast<std::int32_t>(std::round(sy));

                    if (srcX >= 0 && srcX < ScalingBase<true, Owning, Alignment>::bufferWidth && srcY >= 0 && srcY < ScalingBase<true, Owning, Alignment>::bufferHeight) {
                        this->buffer[yB * this->scaled.size.x + xB] = ScalingBase<true, Owning, Alignment>::scalingBuffer[srcY * ScalingBase<true, Owning, Alignment>::bufferWidth + srcX];
                    }
                }
            }
        }
        

        void UpdatePosition(RendertargetBase<Frames>& window, Transform2D& parent) override {
            ScaleData2D oldScale = this->scaled;
            this->ScaleElement(parent);
            if constexpr(Scaling && !Rotating) {
                if(oldScale.size.x != this->scaled.size.x || oldScale.size.y != this->scaled.size.y) {
                    this->buffer.resize(this->scaled.size.x * this->scaled.size.y);
                    ScaleNearestNeighbor();
                }
            } else if constexpr(Rotating) {
                if(oldScale.size.x != this->scaled.size.x || oldScale.size.y != this->scaled.size.y) {
                    this->buffer.resize(this->scaled.size.x * this->scaled.size.y);
                    ScaleRotating();
                }
            } else {
                if(oldScale.size.x != this->scaled.size.x || oldScale.size.y != this->scaled.size.y) {
                    this->buffer.resize(this->scaled.size.x * this->scaled.size.y);
                }
            }
            for(Transform2D* child : this->children) {
                child->UpdatePosition(window, *this);
            }
        }

        std::vector<std::string_view> ResizeText(RendertargetBase<Frames>& window, Transform2D& parent, const std::string_view text, float& size, Font& font, std::uint8_t frame, TextOverflowMode overflowMode = TextOverflowMode::Clip, TextScaleMode scaleMode = TextScaleMode::None) {
            float scale = stbtt_ScaleForPixelHeight(&font.font, size);
            int baseline = (int)(font.ascent * scale);
            
            std::vector<std::string_view> lines;
            std::string_view remaining = text;

            std::uint32_t lineHeight = (font.ascent - font.descent) * scale;
            
            if(overflowMode == TextOverflowMode::Clip) {
                while (!remaining.empty()) {
                    // Find next newline or end of string
                    auto newlinePos = remaining.find('\n');
                    if (newlinePos != std::string_view::npos) {
                        lines.emplace_back(remaining.substr(0, newlinePos));
                        remaining = remaining.substr(newlinePos + 1);
                    } else {
                        lines.emplace_back(remaining);
                        break;
                    }
                }
                std::uint32_t maxWidth = 0;

                for(const std::string_view line: lines) {
                    std::uint32_t lineWidth = 0;
                    for (const char c : line) {
                        int advance, lsb;
                        stbtt_GetCodepointHMetrics(&font.font, c, &advance, &lsb);
                        lineWidth += (int)(advance * scale);
                    }
                    if(lineWidth > maxWidth) {
                        maxWidth = lineWidth;
                    }
                }

                if(scaleMode == TextScaleMode::Element) {
                    std::int32_t logicalPerPixelY = this->anchor.height / this->scaled.size.y;
                    std::int32_t oldHeight = this->anchor.height;
                    std::int32_t logicalPerPixelX = this->anchor.width / this->scaled.size.x;
                    std::int32_t oldwidth = this->anchor.width;
                    this->anchor.height = lineHeight * logicalPerPixelY;
                    this->anchor.width = maxWidth * logicalPerPixelX;
                    if(oldHeight != this->anchor.height || oldwidth != this->anchor.width) {
                        UpdatePosition(window, parent);
                    }
                } else if(scaleMode == TextScaleMode::Font) {
                    float lineHeightPerFont = lineHeight / size;
                    float lineWidthPerFont = maxWidth / size;
                    
                    float maxFontHeight = this->scaled.size.y / lineHeightPerFont;
                    float maxFontWidth = this->scaled.size.x / lineWidthPerFont;

                    size = std::min(maxFontHeight, maxFontWidth);
                } else {
                    if constexpr(Scaling) {
                        lines.resize(ScalingBase<true, Owning, Alignment>::bufferHeight / lines.size());
                    } else {
                        lines.resize(this->scaled.size.y / lines.size());
                    }
                }
            } else {
                while (!remaining.empty()) {
                    std::string_view line;
                    auto newlinePos = remaining.find('\n');
                    if (newlinePos != std::string_view::npos) {
                        line = remaining.substr(0, newlinePos);
                        remaining = remaining.substr(newlinePos + 1);
                    } else {
                        line = remaining;
                        remaining = "";
                    }

                    std::uint32_t lineWidth = 0;
                    std::size_t lastWrapPos = 0; // position of last space that can be used to wrap
                    std::size_t startPos = 0;

                    for (std::size_t i = 0; i < line.size(); ++i) {
                        char c = line[i];

                        // get width of this character
                        int advance, lsb;
                        stbtt_GetCodepointHMetrics(&font.font, c, &advance, &lsb);
                        lineWidth += (std::uint32_t)(advance * scale);

                        // remember last space for wrapping
                        if (c == ' ') {
                            lastWrapPos = i;
                        }

                        // if line exceeds width, wrap
                        if (lineWidth > this->scaled.size.x) {
                            std::size_t wrapPos;
                            if (lastWrapPos > startPos) {
                                wrapPos = lastWrapPos; // wrap at last space
                            } else {
                                wrapPos = i; // no space, hard wrap
                            }

                            // push the line up to wrapPos
                            lines.push_back(line.substr(startPos, wrapPos - startPos));

                            // skip any spaces at the beginning of next line
                            startPos = wrapPos;
                            while (startPos < line.size() && line[startPos] == ' ') {
                                ++startPos;
                            }

                            // reset width and i
                            lineWidth = 0;
                            i = startPos - 1; // -1 because loop will increment i
                        }
                    }

                    // add the remaining part of the line
                    if (startPos < line.size()) {
                        lines.push_back(line.substr(startPos));
                    }
                }

                if(scaleMode == TextScaleMode::Element) {
                    float logicalPerPixelY = this->anchor.height / this->scaled.size.y;
                    float oldHeight = this->anchor.height;
                    this->anchor.height = lineHeight * logicalPerPixelY;
                    if(oldHeight != this->anchor.height) {
                        UpdatePosition(window, parent);
                    }
                } else if(scaleMode == TextScaleMode::Font) {
                    float lineHeightPerFont = lineHeight / size;
                    size = this->scaled.size.y / lineHeightPerFont;
                } else {
                    if constexpr(Scaling) {
                        lines.resize(ScalingBase<true, Owning, Alignment>::bufferHeight / lines.size());
                    } else {
                        lines.resize(this->scaled.size.y / lines.size());
                    }
                }
            }

            return lines;
        }
        void RenderText(std::span<const std::string_view> lines, float size, Vector<std::uint8_t, 4> color, Font& font, std::uint8_t frame, TextAlignment alignment = TextAlignment::Left, std::uint32_t offsetX = 0, std::uint32_t offsetY = 0, OpaqueType opaque = OpaqueType::FullyOpaque) {     
            float scale = stbtt_ScaleForPixelHeight(&font.font, size);
            int baseline = (int)(font.ascent * scale);
            std::uint32_t lineHeight = (font.ascent - font.descent) * scale;
            std::uint32_t currentY = baseline;
            for(std::string_view line : lines) {

                std::uint32_t lineWidth = 0;
                for (const char c : line) {
                    int advance, lsb;
                    stbtt_GetCodepointHMetrics(&font.font, c, &advance, &lsb);
                    lineWidth += (int)(advance * scale);
                }

                std::uint32_t x = 0;
                switch (alignment) {
                    case TextAlignment::Left:
                        x = 0;
                        break;
                    case TextAlignment::Center:
                        x = (this->scaled.size.x - lineWidth) / 2;
                        break;
                    case TextAlignment::Right:
                        x = this->scaled.size.x - lineWidth;
                        break;
                }

                for (std::size_t i = 0; i < line.size(); ++i) {
                    int codepoint = line[i];
                    
                    int ax;
                    int lsb;
                    stbtt_GetCodepointHMetrics(&font.font, codepoint, &ax, &lsb);

                    int c_x1, c_y1, c_x2, c_y2;
                    stbtt_GetCodepointBitmapBox(&font.font, codepoint, scale, scale, &c_x1, &c_y1, &c_x2, &c_y2);

                    int w = c_x2 - c_x1;
                    int h = c_y2 - c_y1;

                    std::vector<unsigned char> bitmap(w * h);
                    stbtt_MakeCodepointBitmap(&font.font, bitmap.data(), w, h, w, scale, scale, codepoint);

                    // Only render characters that fit within the scaled bounds
                    switch(opaque) {
                        case OpaqueType::FullyOpaque: {
                            for (int j = 0; j < h; j++) {
                                for (int i = 0; i < w; i++) {
                                    int bufferX = x + i + c_x1 + offsetX;
                                    int bufferY = currentY + j + c_y1 + offsetY;
                                    
                                    // Only draw pixels that are within our scaled buffer bounds
                                    if constexpr(Scaling) {
                                        if (bufferX >= 0 && bufferX < ScalingBase<true, Owning, Alignment>::bufferWidth && bufferY >= 0 && bufferY < ScalingBase<true, Owning, Alignment>::bufferHeight) {
                                            ScalingBase<true, Owning, Alignment>::scalingBuffer[bufferY * ScalingBase<true, Owning, Alignment>::bufferWidth + bufferX] = {color.r, color.g, color.b, bitmap[j * w + i]};
                                        }
                                    } else {
                                        if (bufferX >= 0 && bufferX < (int)this->scaled.size.x && bufferY >= 0 && bufferY < (int)this->scaled.size.y) {
                                            this->buffer[bufferY * this->scaled.size.x + bufferX] = {color.r, color.g, color.b, bitmap[j * w + i]};
                                        }
                                    }
                                }
                            }
                            break;
                        }
                        case OpaqueType::SemiOpaque: {
                            for (int j = 0; j < h; j++) {
                                for (int i = 0; i < w; i++) {
                                    int bufferX = x + i + c_x1 + offsetX;
                                    int bufferY = currentY + j + c_y1 + offsetY;
                                    
                                    // Only draw pixels that are within our scaled buffer bounds
                                    if constexpr(Scaling) {
                                        if (bufferX >= 0 && bufferX < ScalingBase<true, Owning, Alignment>::bufferWidth && bufferY >= 0 && bufferY < ScalingBase<true, Owning, Alignment>::bufferHeight) {
                                            ScalingBase<true, Owning, Alignment>::scalingBuffer[bufferY * ScalingBase<true, Owning, Alignment>::bufferWidth + bufferX] = {color.r, color.g, color.b, bitmap[j * w + i]};
                                        }
                                    } else {
                                        if (bufferX >= 0 && bufferX < (int)this->scaled.size.x && bufferY >= 0 && bufferY < (int)this->scaled.size.y) {
                                            std::uint8_t alpha = bitmap[j * w + i];
                                            if(alpha != 0) {
                                                this->buffer[bufferY * this->scaled.size.x + bufferX] = {color.r, color.g, color.b, bitmap[j * w + i]};
                                            }
                                        }
                                    }
                                }
                            }
                            break;
                        }
                        case OpaqueType::Transparent: {
                            for (int j = 0; j < h; j++) {
                                for (int i = 0; i < w; i++) {
                                    int bufferX = x + i + c_x1 + offsetX;
                                    int bufferY = currentY + j + c_y1 + offsetY;
                                    
                                    // Only draw pixels that are within our scaled buffer bounds
                                    if constexpr(Scaling) {
                                        if (bufferX >= 0 && bufferX < ScalingBase<true, Owning, Alignment>::bufferWidth && bufferY >= 0 && bufferY < ScalingBase<true, Owning, Alignment>::bufferHeight) {
                                            ScalingBase<true, Owning, Alignment>::scalingBuffer[bufferY * ScalingBase<true, Owning, Alignment>::bufferWidth + bufferX] = {color.r, color.g, color.b, bitmap[j * w + i]};
                                        }
                                    } else {
                                        if (bufferX >= 0 && bufferX < (int)this->scaled.size.x && bufferY >= 0 && bufferY < (int)this->scaled.size.y) {
                                            std::uint8_t alpha = bitmap[j * w + i];

                                            if(alpha == 0) {
                                                continue;
                                            }

                                            Vector<std::uint8_t, 4, Alignment> dst = this->buffer[bufferY * this->scaled.size.x + bufferX];
                                            
                                            float srcA = (alpha / 255.0f) * (color.a / 255.0f);
                                            float dstA = dst.a / 255.0f;

                                            float outA = srcA + dstA * (1.0f - srcA);
                                            this->buffer[bufferY * this->scaled.size.x + bufferX] = Vector<std::uint8_t, 4, Alignment>(
                                                static_cast<std::uint8_t>((color.r * srcA + dst.r * dstA * (1.0f - srcA)) / outA),
                                                static_cast<std::uint8_t>((color.g * srcA + dst.g * dstA * (1.0f - srcA)) / outA),
                                                static_cast<std::uint8_t>((color.b * srcA + dst.b * dstA * (1.0f - srcA)) / outA),
                                                static_cast<std::uint8_t>(outA * 255)
                                            );
                                        }
                                    }
                                }
                            }
                            break;
                        }
                    }

                    x += (int)(ax * scale);

                    if (i + 1 < line.size()) {
                        x += (int)stbtt_GetGlyphKernAdvance(&font.font, codepoint, line[i+1]);
                    }
                }
                currentY += lineHeight;
            }
        }
    };
}