#include "memorymap.hpp"

#include "holly/core/object_list_bits.hpp"
#include "holly/core/region_array.hpp"
#include "holly/core/region_array_bits.hpp"
#include "holly/core/parameter_bits.hpp"
#include "holly/core/parameter.hpp"
#include "holly/ta/global_parameter.hpp"
#include "holly/ta/vertex_parameter.hpp"
#include "holly/ta/parameter_bits.hpp"
#include "holly/holly.hpp"
#include "holly/holly_bits.hpp"

#include "sh7091/sh7091.hpp"
#include "sh7091/pref.hpp"
#include "sh7091/store_queue_transfer.hpp"

void transfer_background_polygon(uint32_t isp_tsp_parameter_start)
{
  using namespace holly::core::parameter;

  using parameter = isp_tsp_parameter<3>;

  volatile parameter * polygon = (volatile parameter *)&texture_memory32[isp_tsp_parameter_start];

  polygon->isp_tsp_instruction_word = isp_tsp_instruction_word::depth_compare_mode::always
                                    | isp_tsp_instruction_word::culling_mode::no_culling;

  polygon->tsp_instruction_word = tsp_instruction_word::src_alpha_instr::one
                                | tsp_instruction_word::dst_alpha_instr::zero
                                | tsp_instruction_word::fog_control::no_fog;

  polygon->texture_control_word = 0;

  polygon->vertex[0].x =  0.0f;
  polygon->vertex[0].y =  0.0f;
  polygon->vertex[0].z =  0.00001f;
  polygon->vertex[0].base_color = 0xff00ff;

  polygon->vertex[1].x = 32.0f;
  polygon->vertex[1].y =  0.0f;
  polygon->vertex[1].z =  0.00001f;
  polygon->vertex[1].base_color = 0xff00ff;

  polygon->vertex[2].x = 32.0f;
  polygon->vertex[2].y = 32.0f;
  polygon->vertex[2].z =  0.00001f;
  polygon->vertex[2].base_color = 0xff00ff;
}

struct vec2 {
  float x;
  float y;
};

struct face {
  float inverse_texture_width;
  float inverse_texture_height;
  float glyph_width;
  float glyph_height;
  int hori_advance;
  int row_stride;
};

static const face ter_u12n = {
  .inverse_texture_width = 1.0f / 128.0f,
  .inverse_texture_height = 1.0f / 64.0f,
  .glyph_width = 6.0f,
  .glyph_height = 12.0f,
  .hori_advance = 6,
  .row_stride = 21,
};

static inline vec2 glyph_texture(const face& face, const vec2& v, int char_code)
{
  int row = char_code / face.row_stride;
  int col = char_code % face.row_stride;

  return {
    (((float)col) * face.glyph_width  + v.x * face.glyph_width) * face.inverse_texture_width,
    (((float)row) * face.glyph_height + v.y * face.glyph_height) * face.inverse_texture_height,
  };
}

static inline vec2 glyph_position(const face& face, const vec2& v, const vec2& p)
{
  return {
    v.x * face.glyph_width + p.x,
    v.y * face.glyph_height + p.y,
  };
}

static inline uint32_t transfer_ta_global_end_of_list(uint32_t store_queue_ix)
{
  using namespace holly::ta;
  using namespace holly::ta::parameter;

  //
  // TA "end of list" global transfer
  //
  volatile global_parameter::end_of_list * end_of_list = (volatile global_parameter::end_of_list *)&store_queue[store_queue_ix];
  store_queue_ix += (sizeof (global_parameter::end_of_list));

  end_of_list->parameter_control_word = parameter_control_word::para_type::end_of_list;

  // start store queue transfer of `end_of_list` to the TA
  pref(end_of_list);

  return store_queue_ix;
}

static inline uint32_t transfer_ta_global_polygon(uint32_t store_queue_ix, uint32_t texture_address)
{
  using namespace holly::core::parameter;
  using namespace holly::ta;
  using namespace holly::ta::parameter;

  volatile global_parameter::polygon_type_0 * polygon = (volatile global_parameter::polygon_type_0 *)&store_queue[store_queue_ix];
  store_queue_ix += (sizeof (global_parameter::polygon_type_0));

  polygon->parameter_control_word = parameter_control_word::para_type::polygon_or_modifier_volume
                                  | parameter_control_word::list_type::opaque
                                  | parameter_control_word::col_type::packed_color
                                  | parameter_control_word::texture;

  polygon->isp_tsp_instruction_word = isp_tsp_instruction_word::depth_compare_mode::greater
                                    | isp_tsp_instruction_word::culling_mode::no_culling;

  polygon->tsp_instruction_word = tsp_instruction_word::src_alpha_instr::one
                                | tsp_instruction_word::dst_alpha_instr::zero
                                | tsp_instruction_word::fog_control::no_fog
                                | tsp_instruction_word::filter_mode::point_sampled
                                | tsp_instruction_word::texture_shading_instruction::decal
                                | tsp_instruction_word::texture_u_size::_128
                                | tsp_instruction_word::texture_v_size::_64;

  polygon->texture_control_word = texture_control_word::pixel_format::palette_4bpp
                                | texture_control_word::scan_order::twiddled
                                | texture_control_word::texture_address(texture_address / 8);


  pref(polygon);

  return store_queue_ix;
}

static inline uint32_t transfer_ta_vertex_quad(uint32_t store_queue_ix,
                                               float ax, float ay, float az, float au, float av, uint32_t ac,
                                               float bx, float by, float bz, float bu, float bv, uint32_t bc,
                                               float cx, float cy, float cz, float cu, float cv, uint32_t cc,
                                               float dx, float dy, float dz, float du, float dv, uint32_t dc)
{
  using namespace holly::ta;
  using namespace holly::ta::parameter;

  //
  // TA polygon vertex transfer
  //

  volatile vertex_parameter::polygon_type_3 * vertex = (volatile vertex_parameter::polygon_type_3 *)&store_queue[store_queue_ix];
  store_queue_ix += (sizeof (vertex_parameter::polygon_type_3)) * 4;

  vertex[0].parameter_control_word = parameter_control_word::para_type::vertex_parameter;
  vertex[0].x = ax;
  vertex[0].y = ay;
  vertex[0].z = az;
  vertex[0].u = au;
  vertex[0].v = av;
  vertex[0].base_color = ac;
  vertex[0].offset_color = 0;

  // start store queue transfer of `vertex[0]` to the TA
  pref(&vertex[0]);

  vertex[1].parameter_control_word = parameter_control_word::para_type::vertex_parameter;
  vertex[1].x = bx;
  vertex[1].y = by;
  vertex[1].z = bz;
  vertex[1].u = bu;
  vertex[1].v = bv;
  vertex[1].base_color = bc;
  vertex[1].offset_color = 0;

  // start store queue transfer of `vertex[1]` to the TA
  pref(&vertex[1]);

  vertex[2].parameter_control_word = parameter_control_word::para_type::vertex_parameter;
  vertex[2].x = dx;
  vertex[2].y = dy;
  vertex[2].z = dz;
  vertex[2].u = du;
  vertex[2].v = dv;
  vertex[2].base_color = dc;
  vertex[2].offset_color = 0;

  // start store queue transfer of `params[2]` to the TA
  pref(&vertex[2]);

  vertex[3].parameter_control_word = parameter_control_word::para_type::vertex_parameter
                                   | parameter_control_word::end_of_strip;
  vertex[3].x = cx;
  vertex[3].y = cy;
  vertex[3].z = cz;
  vertex[3].u = cu;
  vertex[3].v = cv;
  vertex[3].base_color = cc;
  vertex[3].offset_color = 0;

  // start store queue transfer of `params[3]` to the TA
  pref(&vertex[3]);

  return store_queue_ix;
}

uint32_t transfer_glyph(uint32_t store_queue_ix,
                        const face& face,
                        const vec2& t,
                        int char_code)
{
  static const vec2 vtx[] = {
    { 0, 0 },
    { 1, 0 },
    { 1, 1 },
    { 0, 1 },
  };

  if (char_code <= 0x20 || char_code >= 0x7f) {
    return store_queue_ix;
  }

  char_code -= 0x20;

  vec2 ap = glyph_position(face, vtx[0], t);
  vec2 bp = glyph_position(face, vtx[1], t);
  vec2 cp = glyph_position(face, vtx[2], t);
  vec2 dp = glyph_position(face, vtx[3], t);

  vec2 at = glyph_texture(face, vtx[0], char_code);
  vec2 bt = glyph_texture(face, vtx[1], char_code);
  vec2 ct = glyph_texture(face, vtx[2], char_code);
  vec2 dt = glyph_texture(face, vtx[3], char_code);

  store_queue_ix = transfer_ta_vertex_quad(store_queue_ix,
                                           ap.x, ap.y, 0.1f, at.x, at.y, 0,
                                           bp.x, bp.y, 0.1f, bt.x, bt.y, 0,
                                           cp.x, cp.y, 0.1f, ct.x, ct.y, 0,
                                           dp.x, dp.y, 0.1f, dt.x, dt.y, 0);

  return store_queue_ix;
}

void transfer_scene(uint32_t texture_address)
{
  {
    using namespace sh7091;
    using sh7091::sh7091;

    // set the store queue destination address to the TA Polygon Converter FIFO
    sh7091.CCN.QACR0 = sh7091::ccn::qacr0::address(ta_fifo_polygon_converter);
    sh7091.CCN.QACR1 = sh7091::ccn::qacr1::address(ta_fifo_polygon_converter);
  }

  uint32_t store_queue_ix = 0;

  store_queue_ix = transfer_ta_global_polygon(store_queue_ix, texture_address);

  store_queue_ix = transfer_glyph(store_queue_ix,
                                  ter_u12n,
                                  vec2(10, 10),
                                  'a');

  store_queue_ix = transfer_ta_global_end_of_list(store_queue_ix);
}

const uint8_t texture[] __attribute__((aligned(4))) = {
  #embed "font/ter_u12n.128x64.palette_4bpp.twiddled"
};

void transfer_texture(uint32_t texture_start)
{
  // use 4-byte transfers to texture memory, for slightly increased transfer
  // speed
  //
  // It would be even faster to use the SH4 store queue for this operation, or
  // SH4 DMA.

  sh7091::store_queue_transfer::copy((void *)&texture_memory64[texture_start], texture, (sizeof (texture)));
}

void main()
{
  using namespace holly;
  using namespace holly::core;
  using holly::holly;

  /* palette */
  holly.PAL_RAM_CTRL = holly::pal_ram_ctrl::pixel_format::argb4444;

  holly.PALETTE_RAM[0] = 0x0000;
  holly.PALETTE_RAM[1] = 0xffff;

  holly.PT_ALPHA_REF = 0xff;

  /*
    a very simple memory map:

    the ordering within texture memory is not significant, and could be
    anything
  */
  uint32_t framebuffer_start       = 0x200000; // intentionally the same address that the boot rom used to draw the SEGA logo
  uint32_t isp_tsp_parameter_start = 0x400000;
  uint32_t region_array_start      = 0x500000;
  uint32_t object_list_start       = 0x100000;

  // these addresses are in "64-bit" texture memory address space:
  uint32_t texture_start           = 0x700000;

  const int tile_y_num = 480 / 32;
  const int tile_x_num = 640 / 32;

  region_array::list_block_size list_block_size = {
    .opaque = 8 * 4,
  };

  region_array::transfer(tile_x_num,
                         tile_y_num,
                         list_block_size,
                         region_array_start,
                         object_list_start);

  transfer_background_polygon(isp_tsp_parameter_start);

  //////////////////////////////////////////////////////////////////////////////
  // transfer the texture image to texture ram
  //////////////////////////////////////////////////////////////////////////////

  transfer_texture(texture_start);

  //////////////////////////////////////////////////////////////////////////////
  // configure the TA
  //////////////////////////////////////////////////////////////////////////////

  // TA_GLOB_TILE_CLIP restricts which "object pointer blocks" are written
  // to.
  //
  // This can also be used to implement "windowing", as long as the desired
  // window size happens to be a multiple of 32 pixels. The "User Tile Clip" TA
  // control parameter can also ~equivalently be used as many times as desired
  // within a single TA initialization to produce an identical effect.
  //
  // See DCDBSysArc990907E.pdf page 183.
  holly.TA_GLOB_TILE_CLIP = ta_glob_tile_clip::tile_y_num(tile_y_num - 1)
                          | ta_glob_tile_clip::tile_x_num(tile_x_num - 1);

  // While CORE supports arbitrary-length object lists, the TA uses "object
  // pointer blocks" as a memory allocation strategy. These fixed-length blocks
  // can still have infinite length via "object pointer block links". This
  // mechanism is illustrated in DCDBSysArc990907E.pdf page 188.
  holly.TA_ALLOC_CTRL = ta_alloc_ctrl::opb_mode::increasing_addresses
                      | ta_alloc_ctrl::o_opb::_8x4byte;

  // While building object lists, the TA contains an internal index (exposed as
  // the read-only TA_ITP_CURRENT) for the next address that new ISP/TSP will be
  // stored at. The initial value of this index is TA_ISP_BASE.

  // reserve space in ISP/TSP parameters for the background parameter
  using polygon = holly::core::parameter::isp_tsp_parameter<3>;
  uint32_t ta_isp_base_offset = (sizeof (polygon)) * 1;

  holly.TA_ISP_BASE = isp_tsp_parameter_start + ta_isp_base_offset;
  holly.TA_ISP_LIMIT = isp_tsp_parameter_start + 0x100000;

  // Similarly, the TA also contains, for up to 600 tiles, an internal index for
  // the next address that an object list entry will be stored for each
  // tile. These internal indicies are partially exposed via the read-only
  // TA_OL_POINTERS.
  holly.TA_OL_BASE = object_list_start;

  // TA_OL_LIMIT, DCDBSysArc990907E.pdf page 385:
  //
  // >   Because the TA may automatically store data in the address that is
  // >   specified by this register, it must not be used for other data.  For
  // >   example, the address specified here must not be the same as the address
  // >   in the TA_ISP_BASE register.
  holly.TA_OL_LIMIT = object_list_start + 0x100000 - 32;

  //////////////////////////////////////////////////////////////////////////////
  // configure CORE
  //////////////////////////////////////////////////////////////////////////////

  // REGION_BASE is the (texture memory-relative) address of the region array.
  holly.REGION_BASE = region_array_start;

  // PARAM_BASE is the (texture memory-relative) address of ISP/TSP parameters.
  // Anything that references an ISP/TSP parameter does so relative to this
  // address (and not relative to the beginning of texture memory).
  holly.PARAM_BASE = isp_tsp_parameter_start;

  // Set the offset of the background ISP/TSP parameter, relative to PARAM_BASE
  // SKIP is related to the size of each vertex
  uint32_t background_offset = 0;

  holly.ISP_BACKGND_T = isp_backgnd_t::tag_address(background_offset / 4)
                      | isp_backgnd_t::tag_offset(0)
                      | isp_backgnd_t::skip(1);

  // FB_W_SOF1 is the (texture memory-relative) address of the framebuffer that
  // will be written to when a tile is rendered/flushed.
  holly.FB_W_SOF1 = framebuffer_start;

  // without waiting for rendering to actually complete, immediately display the
  // framebuffer.
  holly.FB_R_SOF1 = framebuffer_start;

  // TA_LIST_INIT needs to be written (every frame) prior to the first FIFO
  // write.
  holly.TA_LIST_INIT = ta_list_init::list_init;

  // dummy TA_LIST_INIT read; DCDBSysArc990907E.pdf in multiple places says this
  // step is required.
  (void)holly.TA_LIST_INIT;

  transfer_scene(texture_start);

  //////////////////////////////////////////////////////////////////////////////
  // wait for vertical synchronization (and the TA)
  //////////////////////////////////////////////////////////////////////////////

  while (!(spg_status::vsync(holly.SPG_STATUS)));
  while (spg_status::vsync(holly.SPG_STATUS));

  //////////////////////////////////////////////////////////////////////////////
  // start the actual rasterization
  //////////////////////////////////////////////////////////////////////////////

  // start the actual render--the rendering process begins by interpreting the
  // region array
  holly.STARTRENDER = 1;
}