#include "editor_2d.h"
#include <stdlib.h>
#include <string.h>

int editor2d_init(Editor2D* e, ID3D11Device* dev) {
    memset(e, 0, sizeof(*e));

    e->shader = shader_create();
    if (!shader_compile(e->shader, dev, NULL, NULL, 0, 0)) return 0;

    D3D11_BUFFER_DESC bd = {0};
    bd.ByteWidth = ED2D_MAX_QUADS * 4 * sizeof(Ed2DVert);
    bd.Usage = D3D11_USAGE_DYNAMIC;
    bd.BindFlags = D3D11_BIND_VERTEX_BUFFER;
    bd.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;
    if (FAILED(dev->lpVtbl->CreateBuffer(dev, &bd, NULL, &e->vb))) return 0;

    bd.ByteWidth = ED2D_MAX_QUADS * 6 * sizeof(uint32_t);
    bd.Usage = D3D11_USAGE_DEFAULT;
    bd.BindFlags = D3D11_BIND_INDEX_BUFFER;
    bd.CPUAccessFlags = 0;
    uint32_t* idx = (uint32_t*)malloc(ED2D_MAX_QUADS * 6 * sizeof(uint32_t));
    for (int i = 0; i < ED2D_MAX_QUADS; i++) {
        uint32_t b2 = i * 4;
        idx[i*6]=b2; idx[i*6+1]=b2+1; idx[i*6+2]=b2+2;
        idx[i*6+3]=b2; idx[i*6+4]=b2+2; idx[i*6+5]=b2+3;
    }
    D3D11_SUBRESOURCE_DATA sd = {0}; sd.pSysMem = idx;
    dev->lpVtbl->CreateBuffer(dev, &bd, &sd, &e->ib);
    free(idx);

    e->verts = (Ed2DVert*)malloc(ED2D_MAX_QUADS * 4 * sizeof(Ed2DVert));

    D3D11_BLEND_DESC bdesc = {0};
    bdesc.RenderTarget[0].BlendEnable = TRUE;
    bdesc.RenderTarget[0].SrcBlend = D3D11_BLEND_SRC_ALPHA;
    bdesc.RenderTarget[0].DestBlend = D3D11_BLEND_INV_SRC_ALPHA;
    bdesc.RenderTarget[0].BlendOp = D3D11_BLEND_OP_ADD;
    bdesc.RenderTarget[0].SrcBlendAlpha = D3D11_BLEND_ONE;
    bdesc.RenderTarget[0].DestBlendAlpha = D3D11_BLEND_ZERO;
    bdesc.RenderTarget[0].BlendOpAlpha = D3D11_BLEND_OP_ADD;
    dev->lpVtbl->CreateBlendState(dev, &bdesc, &e->blend);

    D3D11_DEPTH_STENCIL_DESC dsdesc = {0};
    dsdesc.DepthEnable = FALSE;
    dsdesc.DepthWriteMask = D3D11_DEPTH_WRITE_MASK_ZERO;
    dev->lpVtbl->CreateDepthStencilState(dev, &dsdesc, &e->ds_no_depth);

    return 1;
}

void editor2d_destroy(Editor2D* e) {
    if (!e) return;
    if (e->ds_no_depth) e->ds_no_depth->lpVtbl->Release(e->ds_no_depth);
    if (e->blend) e->blend->lpVtbl->Release(e->blend);
    if (e->ib) e->ib->lpVtbl->Release(e->ib);
    if (e->vb) e->vb->lpVtbl->Release(e->vb);
    shader_destroy(e->shader);
    free(e->verts);
    memset(e, 0, sizeof(*e));
}

void editor2d_begin(Editor2D* e, float sw, float sh) {
    e->quad_count = 0;
    e->screen_w = sw;
    e->screen_h = sh;

    memset(e->wvp, 0, sizeof(e->wvp));
    e->wvp[0] = 2.0f / sw;
    e->wvp[5] = -2.0f / sh;
    e->wvp[12] = -1.0f;
    e->wvp[13] = 1.0f;
    e->wvp[15] = 1.0f;
}

void editor2d_rect(Editor2D* e, float x, float y, float w, float h, float r, float g, float b, float a) {
    if (e->quad_count >= ED2D_MAX_QUADS) return;
    int vi = e->quad_count * 4;
    e->verts[vi+0] = (Ed2DVert){x,   y,   0, 0,0,-1, 0,1, r,g,b,a};
    e->verts[vi+1] = (Ed2DVert){x+w, y,   0, 0,0,-1, 1,1, r,g,b,a};
    e->verts[vi+2] = (Ed2DVert){x+w, y+h, 0, 0,0,-1, 1,0, r,g,b,a};
    e->verts[vi+3] = (Ed2DVert){x,   y+h, 0, 0,0,-1, 0,0, r,g,b,a};
    e->quad_count++;
}

void editor2d_rect_border(Editor2D* e, float x, float y, float w, float h, float r, float g, float b, float a, float t) {
    editor2d_rect(e, x, y, w, t, r, g, b, a);
    editor2d_rect(e, x, y+h-t, w, t, r, g, b, a);
    editor2d_rect(e, x, y, t, h, r, g, b, a);
    editor2d_rect(e, x+w-t, y, t, h, r, g, b, a);
}

void editor2d_end(Editor2D* e, ID3D11DeviceContext* ctx) {
    if (e->quad_count == 0) return;

    D3D11_MAPPED_SUBRESOURCE mapped;
    if (FAILED(ctx->lpVtbl->Map(ctx, (ID3D11Resource*)e->vb, 0, D3D11_MAP_WRITE_DISCARD, 0, &mapped))) return;
    memcpy(mapped.pData, e->verts, (size_t)e->quad_count * 4 * sizeof(Ed2DVert));
    ctx->lpVtbl->Unmap(ctx, (ID3D11Resource*)e->vb, 0);

    if (e->rtv) {
        ctx->lpVtbl->OMSetRenderTargets(ctx, 1, &e->rtv, NULL);
    }

    D3D11_VIEWPORT vp = {0};
    vp.Width = e->screen_w;
    vp.Height = e->screen_h;
    vp.MaxDepth = 1.0f;
    ctx->lpVtbl->RSSetViewports(ctx, 1, &vp);

    shader_bind(e->shader, ctx);
    shader_set_matrix(e->shader, ctx, e->wvp);

    UINT stride = sizeof(Ed2DVert), offset = 0;
    ctx->lpVtbl->IASetVertexBuffers(ctx, 0, 1, &e->vb, &stride, &offset);
    ctx->lpVtbl->IASetIndexBuffer(ctx, e->ib, DXGI_FORMAT_R32_UINT, 0);
    ctx->lpVtbl->IASetPrimitiveTopology(ctx, D3D_PRIMITIVE_TOPOLOGY_TRIANGLELIST);

    float bf[4] = {0};
    ctx->lpVtbl->OMSetBlendState(ctx, e->blend, bf, 0xFFFFFFFF);
    ctx->lpVtbl->OMSetDepthStencilState(ctx, e->ds_no_depth, 0);

    ctx->lpVtbl->DrawIndexed(ctx, (UINT)(e->quad_count * 6), 0, 0);
}