#include <stdbool.h> // bool
#include <math.h> // sinf()
#include "util.h" // warn()/die()
#include "color.h" // set_color()
#include "draw.h"
#include "sprites.h"
#include "draw-text.h"
#include "bg-style.h"

#define M_2_PI (2.0 * 3.1415926)

static size_t
get_cell_size(
  const draw_ctx_t * const draw_ctx
) {
  return 32 + 8 * *draw_ctx->zoom;
}

static SDL_Rect
get_cell_rect(
  const draw_ctx_t * const draw_ctx,
  const sok_pos_t pos
) {
  const size_t cell_size = get_cell_size(draw_ctx);

  return (SDL_Rect) {
    draw_ctx->render_ofs_x + pos.x * cell_size,
    draw_ctx->render_ofs_y + pos.y * cell_size,
    cell_size,
    cell_size
  };
}

static void
on_size(
  const sok_ctx_t * const ctx,
  const sok_pos_t level_size,
  void * const data
) {
  draw_ctx_t * const draw_ctx = data;
  const size_t cell_size = get_cell_size(draw_ctx);

  // get renderer size
  int renderer_x, renderer_y;
  if (SDL_GetRendererOutputSize(draw_ctx->renderer, &renderer_x, &renderer_y)) {
    die("SDL_GetRendererOutputSize(): %s", SDL_GetError());
  }

  // calculate renderer offset
  draw_ctx->render_ofs_x = (renderer_x - level_size.x * cell_size) / 2;
  draw_ctx->render_ofs_y = (renderer_y - level_size.y * cell_size) / 2;
}

static void
draw_cell(
  draw_ctx_t * const draw_ctx,
  const sok_pos_t pos,
  const sprite_t sprite
) {
  const SDL_Rect rect = get_cell_rect(draw_ctx, pos);

  SDL_Texture *tex = draw_ctx->sprites[sprite];
  if (SDL_RenderCopy(draw_ctx->renderer, tex, NULL, &rect)) {
    die("SDL_RenderCopy(): %s", SDL_GetError());
  }
}

static void
draw_home(
  draw_ctx_t * const draw_ctx,
  const sok_pos_t pos
) {
  const SDL_Rect rect = get_cell_rect(draw_ctx, pos);

  SDL_Texture *tex = draw_ctx->sprites[SPRITE_HOME];
  if (sok_ctx_is_done(draw_ctx->ctx)) {
    const Uint32 ticks = SDL_GetTicks();
    const double angle = 10 * sin(ticks * M_2_PI / 1000.0);
    if (SDL_RenderCopyEx(draw_ctx->renderer, tex, NULL, &rect, angle, NULL, SDL_FLIP_NONE)) {
      die("SDL_RenderCopyEx(): %s", SDL_GetError());
    }
  } else {
    if (SDL_RenderCopy(draw_ctx->renderer, tex, NULL, &rect)) {
      die("SDL_RenderCopy(): %s", SDL_GetError());
    }
  }
}

static void
draw_border(
  draw_ctx_t * const draw_ctx,
  const sok_pos_t level_size
) {
  const size_t cell_size = get_cell_size(draw_ctx);

  // calc rect
  const SDL_Rect rect = {
    draw_ctx->render_ofs_x - cell_size / 8,
    draw_ctx->render_ofs_y - cell_size / 8,
    level_size.x * cell_size + cell_size / 4,
    level_size.y * cell_size + cell_size / 4,
  };

  // set color
  if (SDL_SetRenderDrawColor(draw_ctx->renderer, 0, 0, 0, 0xFF)) {
    die("SDL_SetRenderDrawColor(): %s", SDL_GetError());
  }

  // fill border rect
  if (SDL_RenderFillRect(draw_ctx->renderer, &rect)) {
    die("SDL_RenderFillRect(): %s", SDL_GetError());
  }
}

static bool
draw_sprites_on_size(
  const sok_ctx_t * const ctx,
  const sok_pos_t level_size,
  void * const data
) {
  on_size(ctx, level_size, data);
  draw_ctx_t * const draw_ctx = data;

  draw_border(draw_ctx, level_size);

  // draw floor
  for (size_t y = 0; y < level_size.y; y++) {
    for (size_t x = 0; x < level_size.x; x++) {
      if (x > 0 && y > 0 && x < level_size.x - 1 && y < level_size.y - 1) {
        const sok_pos_t pos = { x, y };
        draw_cell(draw_ctx, pos, SPRITE_FLOOR);
      }
    }
  }

  return true;
}

static bool
draw_sprites_on_wall(
  const sok_ctx_t * const ctx,
  const sok_pos_t pos,
  void * const data
) {
  draw_ctx_t * const draw_ctx = data;
  draw_cell(draw_ctx, pos, SPRITE_WALL);
  return true;
}

static bool
draw_sprites_on_goal(
  const sok_ctx_t * const ctx,
  const sok_pos_t pos,
  const bool has_player,
  const bool has_box,
  void * const data
) {
  draw_ctx_t * const draw_ctx = data;
  draw_cell(draw_ctx, pos, SPRITE_GOAL);
  return true;
}

static bool
draw_sprites_on_home(
  const sok_ctx_t * const ctx,
  const sok_pos_t pos,
  const bool has_goal,
  void * const data
) {
  draw_ctx_t * const draw_ctx = data;
  draw_home(draw_ctx, pos);
  return true;
}

static bool
draw_sprites_on_box(
  const sok_ctx_t * const ctx,
  const sok_pos_t pos,
  const bool has_goal,
  void * const data
) {
  draw_ctx_t * const draw_ctx = data;
  draw_cell(draw_ctx, pos, SPRITE_BOX);
  return true;
}

static const sok_ctx_walk_cbs_t
DRAW_CBS = {
  .on_size        = draw_sprites_on_size,
  .on_wall        = draw_sprites_on_wall,
  .on_goal        = draw_sprites_on_goal,
  .on_home        = draw_sprites_on_home,
  .on_box         = draw_sprites_on_box,
};

static const text_style_t
TITLE_STYLE = {
  .align  = TEXT_ALIGN_TOP_CENTER,
  .pad    = { 0, 10 },
  .colors = {
    { 0xff, 0xff, 0xff, 0xff },
    { 0x00, 0x00, 0x00, 0xff },
  },
};

static void
draw_title_text(
  draw_ctx_t * const draw_ctx
) {
  // build text
  char buf[256];
  snprintf(
    buf, sizeof(buf),
    " %s: %s (#%zu) ",
    draw_ctx->level->pack,
    draw_ctx->level->name,
    *draw_ctx->level_num
  );

  // draw text
  draw_text(draw_ctx->renderer, draw_ctx->font, &TITLE_STYLE, buf);
}

static const text_style_t
MOVES_STYLE = {
  .align  = TEXT_ALIGN_BOTTOM_LEFT,
  .pad    = { 10, 10 },
  .colors = {
    { 0xff, 0xff, 0xff, 0xff },
    { 0x00, 0x00, 0x00, 0xff },
  },
};

static void
draw_moves_text(
  draw_ctx_t * const draw_ctx
) {
  // build text
  char buf[256];
  snprintf(
    buf, sizeof(buf),
    " Moves: %zu%s ",
    draw_ctx->ctx->num_moves,
    sok_ctx_is_done(draw_ctx->ctx) ? " (Won!)" : ""
  );

  // draw text
  draw_text(draw_ctx->renderer, draw_ctx->font, &MOVES_STYLE, buf);
}

static const text_style_t
HELP_STYLE = {
  .align  = TEXT_ALIGN_BOTTOM_RIGHT,
  .pad    = { 10, 10 },
  .colors = {
    { 0xff, 0xff, 0xff, 0xff },
    { 0x00, 0x00, 0x00, 0xff },
  },
};


static void
draw_help_text(
  draw_ctx_t * const draw_ctx
) {
  // build text
  char buf[256];
#define D "     "
  snprintf(
    buf, sizeof(buf),
    " %sU: Undo" D "R: Reset" D "S: Solve" D "Q: Quit ",
    sok_ctx_is_done(draw_ctx->ctx) ? "Space: Next Level" D : ""
  );
#undef D

  // draw text
  draw_text(draw_ctx->renderer, draw_ctx->font, &HELP_STYLE, buf);
}

static const bg_style_t
BG_STYLES[] = {{
  // normal style
  .r = { .base = 0x00 },
  .g = { .base = 0x00 },
  .b = { .base = 0x00 },
  .a = { .base = 0xFF },
}, {
  // won style
  .r = {
    .base       = 0x66,
    .amplitude  = 0x33,
    .phase      = 1000,
    .period     = 2000,
  },

  .g = {
    .base       = 0x66,
    .amplitude  = 0x33,
    .phase      = 3000,
    .period     = 5000,
  },

  .b = {
    .base       = 0x66,
    .amplitude  = 0x33,
    .phase      = 5000,
    .period     = 7000,
  },

  .a = {
    .base       = 0xFF,
  },
}};

static void
draw_bg(
  draw_ctx_t * const draw_ctx
) {
  // get color
  const SDL_Color c = bg_style_get_color(
    BG_STYLES + (sok_ctx_is_done(draw_ctx->ctx) ? 1 : 0),
    SDL_GetTicks()
  );

  // set color
  if (SDL_SetRenderDrawColor(draw_ctx->renderer, c.r, c.g, c.b, c.a)) {
    die("SDL_SetRenderDrawColor(): %s", SDL_GetError());
  }

  // clear background
  SDL_RenderClear(draw_ctx->renderer);
}

void
draw(
  draw_ctx_t * const draw_ctx
) {
  // clear background
  draw_bg(draw_ctx);

  // render level
  sok_ctx_walk(draw_ctx->ctx, &DRAW_CBS, draw_ctx);

  // render text
  draw_title_text(draw_ctx);
  draw_moves_text(draw_ctx);
  draw_help_text(draw_ctx);

  // flip
  SDL_RenderPresent(draw_ctx->renderer);
}