/* The C half of the raylib binding: one wrapper per `declare` in raylib.flan.
 *
 * The wrappers exist so that no aggregate is ever passed or returned across
 * the Flan/C boundary. raylib takes Color by value and returns Vector2 by
 * value, and a small aggregate is passed differently on x86-64 (<2 x float>,
 * i32), on arm64, and on wasm32. Here, clang classifies each one correctly for
 * whichever target the build is for; in the Flan backend it would be three
 * conventions to reimplement. Everything below therefore trades in scalars and
 * pointers only — see raylib.flan.
 *
 * raylib's own headers are not needed and not used: these prototypes are the
 * declarations, so the build has no dependency on raylib-devel being
 * installed, only on the shared library being linkable.
 */

#include <stdbool.h>
#include <stddef.h>
#include <limits.h>
#include <string.h>

typedef struct { float x, y; } Vector2;
typedef struct { unsigned char r, g, b, a; } Color;
typedef struct { unsigned int id; int width, height, mipmaps, format; } Texture2D;
typedef struct { float x, y, width, height; } Rectangle;
typedef struct { Vector2 offset, target; float rotation, zoom; } Camera2D;

extern void  InitWindow(int width, int height, const char *title);
extern void  CloseWindow(void);
extern bool  WindowShouldClose(void);
extern void  SetTargetFPS(int fps);
extern void  SetTraceLogLevel(int level);
extern bool  IsKeyPressed(int key);
extern bool  IsKeyDown(int key);
extern bool  IsKeyReleased(int key);
extern bool  IsMouseButtonPressed(int button);
extern bool  IsMouseButtonDown(int button);
extern bool  IsMouseButtonReleased(int button);
extern Vector2 GetMousePosition(void);
extern Color GetColor(unsigned int hex);
extern void  BeginDrawing(void);
extern void  EndDrawing(void);
extern void  DrawFPS(int x, int y);
extern void  ClearBackground(Color color);
extern void  DrawRectangle(int x, int y, int width, int height, Color color);
extern void  SetShapesTexture(Texture2D texture, Rectangle source);
extern Texture2D GetShapesTexture(void);
extern Rectangle GetShapesTextureRectangle(void);
extern Rectangle GetCollisionRec(Rectangle a, Rectangle b);
extern Texture2D LoadTexture(const char *fileName);
extern bool  IsTextureValid(Texture2D texture);
extern void  UnloadTexture(Texture2D texture);
extern void  DrawTexture(Texture2D texture, int posX, int posY, Color tint);
extern void  DrawTextureV(Texture2D texture, Vector2 position, Color tint);
extern void  DrawTextureEx(Texture2D texture, Vector2 position, float rotation,
                           float scale, Color tint);
extern void  DrawTextureRec(Texture2D texture, Rectangle source,
                            Vector2 position, Color tint);
extern void  BeginMode2D(Camera2D camera);
extern void  EndMode2D(void);
extern Vector2 GetScreenToWorld2D(Vector2 position, Camera2D camera);
extern Vector2 GetWorldToScreen2D(Vector2 position, Camera2D camera);
extern bool  CheckCollisionRecs(Rectangle rec1, Rectangle rec2);
extern bool  CheckCollisionCircles(Vector2 c1, float r1, Vector2 c2, float r2);
extern bool  CheckCollisionCircleRec(Vector2 center, float radius, Rectangle rec);
extern bool  CheckCollisionCircleLine(Vector2 center, float radius,
                                      Vector2 p1, Vector2 p2);
extern bool  CheckCollisionPointRec(Vector2 point, Rectangle rec);
extern bool  CheckCollisionPointCircle(Vector2 point, Vector2 center, float radius);
extern bool  CheckCollisionPointTriangle(Vector2 point, Vector2 p1, Vector2 p2,
                                         Vector2 p3);
extern bool  CheckCollisionPointLine(Vector2 point, Vector2 p1, Vector2 p2,
                                     int threshold);
extern bool  CheckCollisionPointPoly(Vector2 point, const Vector2 *points,
                                     int pointCount);
extern bool  CheckCollisionLines(Vector2 a1, Vector2 a2, Vector2 b1, Vector2 b2,
                                 Vector2 *collisionPoint);

/* A Flan string arrives as ptr+len and is not NUL-terminated, so a C API that
 * wants a C string needs a copy. Two callers want one: the window title and a
 * texture's file path. Each passes a buffer big enough for what it is — 256
 * for a title, PATH_MAX for a path — and truncating is better than reading
 * past the end. A truncated path fails to open and LoadTexture returns an id
 * of 0, which is what texture-valid? is for. */
static const char *cstr(const char *p, long long n, char *buf, size_t cap) {
  size_t k = (size_t)n < cap - 1 ? (size_t)n : cap - 1;
  memcpy(buf, p, k);
  buf[k] = '\0';
  return buf;
}

void flan_rl_init_window(int width, int height, const char *title, long long n) {
  char buf[256];
  InitWindow(width, height, cstr(title, n, buf, sizeof buf));
}

void flan_rl_close_window(void)          { CloseWindow(); }
bool flan_rl_window_should_close(void)   { return WindowShouldClose(); }
void flan_rl_set_target_fps(int fps)     { SetTargetFPS(fps); }
void flan_rl_set_trace_log_level(int l)  { SetTraceLogLevel(l); }

bool flan_rl_is_key_pressed(int key)     { return IsKeyPressed(key); }
bool flan_rl_is_key_down(int key)        { return IsKeyDown(key); }
bool flan_rl_is_key_released(int key)    { return IsKeyReleased(key); }

bool flan_rl_is_mouse_button_pressed(int b)  { return IsMouseButtonPressed(b); }
bool flan_rl_is_mouse_button_down(int b)     { return IsMouseButtonDown(b); }
bool flan_rl_is_mouse_button_released(int b) { return IsMouseButtonReleased(b); }

void flan_rl_get_mouse_position(Vector2 *out) { *out = GetMousePosition(); }

void flan_rl_get_color(unsigned int hex, Color *out) { *out = GetColor(hex); }

void flan_rl_begin_drawing(void)         { BeginDrawing(); }
void flan_rl_end_drawing(void)           { EndDrawing(); }
void flan_rl_draw_fps(int x, int y)      { DrawFPS(x, y); }

void flan_rl_clear_background(const Color *color) { ClearBackground(*color); }

void flan_rl_draw_rectangle(int x, int y, int width, int height,
                            const Color *color) {
  DrawRectangle(x, y, width, height, *color);
}

void flan_rl_set_shapes_texture(const Texture2D *texture, const Rectangle *source) {
  SetShapesTexture(*texture, *source);
}

void flan_rl_get_shapes_texture(Texture2D *out) { *out = GetShapesTexture(); }

void flan_rl_get_shapes_texture_rectangle(Rectangle *out) {
  *out = GetShapesTextureRectangle();
}

void flan_rl_get_collision_rec(const Rectangle *a, const Rectangle *b,
                               Rectangle *out) {
  *out = GetCollisionRec(*a, *b);
}

void flan_rl_load_texture(const char *path, long long n, Texture2D *out) {
  char buf[PATH_MAX];
  *out = LoadTexture(cstr(path, n, buf, sizeof buf));
}

bool flan_rl_is_texture_valid(const Texture2D *texture) {
  return IsTextureValid(*texture);
}

void flan_rl_unload_texture(const Texture2D *texture) { UnloadTexture(*texture); }

void flan_rl_draw_texture(const Texture2D *texture, int x, int y,
                          const Color *tint) {
  DrawTexture(*texture, x, y, *tint);
}

void flan_rl_draw_texture_v(const Texture2D *texture, const Vector2 *position,
                            const Color *tint) {
  DrawTextureV(*texture, *position, *tint);
}

void flan_rl_draw_texture_ex(const Texture2D *texture, const Vector2 *position,
                             float rotation, float scale, const Color *tint) {
  DrawTextureEx(*texture, *position, rotation, scale, *tint);
}

void flan_rl_draw_texture_rec(const Texture2D *texture, const Rectangle *source,
                              const Vector2 *position, const Color *tint) {
  DrawTextureRec(*texture, *source, *position, *tint);
}

void flan_rl_begin_mode_2d(const Camera2D *camera) { BeginMode2D(*camera); }
void flan_rl_end_mode_2d(void)                     { EndMode2D(); }

void flan_rl_get_screen_to_world_2d(const Vector2 *position,
                                    const Camera2D *camera, Vector2 *out) {
  *out = GetScreenToWorld2D(*position, *camera);
}

void flan_rl_get_world_to_screen_2d(const Vector2 *position,
                                    const Camera2D *camera, Vector2 *out) {
  *out = GetWorldToScreen2D(*position, *camera);
}

bool flan_rl_check_collision_recs(const Rectangle *a, const Rectangle *b) {
  return CheckCollisionRecs(*a, *b);
}

bool flan_rl_check_collision_circles(const Vector2 *c1, float r1,
                                     const Vector2 *c2, float r2) {
  return CheckCollisionCircles(*c1, r1, *c2, r2);
}

bool flan_rl_check_collision_circle_rec(const Vector2 *center, float radius,
                                        const Rectangle *rec) {
  return CheckCollisionCircleRec(*center, radius, *rec);
}

bool flan_rl_check_collision_circle_line(const Vector2 *center, float radius,
                                         const Vector2 *p1, const Vector2 *p2) {
  return CheckCollisionCircleLine(*center, radius, *p1, *p2);
}

bool flan_rl_check_collision_point_rec(const Vector2 *point, const Rectangle *rec) {
  return CheckCollisionPointRec(*point, *rec);
}

bool flan_rl_check_collision_point_circle(const Vector2 *point,
                                          const Vector2 *center, float radius) {
  return CheckCollisionPointCircle(*point, *center, radius);
}

bool flan_rl_check_collision_point_triangle(const Vector2 *point, const Vector2 *a,
                                            const Vector2 *b, const Vector2 *c) {
  return CheckCollisionPointTriangle(*point, *a, *b, *c);
}

bool flan_rl_check_collision_point_line(const Vector2 *point, const Vector2 *p1,
                                        const Vector2 *p2, int threshold) {
  return CheckCollisionPointLine(*point, *p1, *p2, threshold);
}

/* A Flan slice arrives as ptr+len, the same shape a string does. raylib wants
 * an int count, and a polygon with more than INT_MAX points is not a thing
 * that happens; the clamp is there so the conversion is not silent. */
bool flan_rl_check_collision_point_poly(const Vector2 *point,
                                        const Vector2 *points, long long n) {
  if (n > INT_MAX) n = INT_MAX;
  return CheckCollisionPointPoly(*point, points, (int)n);
}

bool flan_rl_check_collision_lines(const Vector2 *a1, const Vector2 *a2,
                                   const Vector2 *b1, const Vector2 *b2,
                                   Vector2 *out) {
  return CheckCollisionLines(*a1, *a2, *b1, *b2, out);
}

/* ── Images ─────────────────────────────────────────────────────────
 *
 * An Image is pixels in RAM, so all of this runs with no window and no GL
 * context — which is why it is the part of the package that a headless test
 * can actually assert rather than merely link. `data` is the pixel buffer
 * raylib owns; `format` is a PixelFormat enum and GenImageColor makes 7
 * (uncompressed R8G8B8A8).
 *
 * raylib 5.5 spells the predicate IsImageValid. IsImageReady, which the 5.1
 * header still had, is gone — checked with nm -D, not remembered.
 */
typedef struct { void *data; int width, height, mipmaps, format; } Image;

extern Image LoadImage(const char *fileName);
extern bool  IsImageValid(Image image);
extern void  UnloadImage(Image image);
extern bool  ExportImage(Image image, const char *fileName);
extern Image GenImageColor(int width, int height, Color color);
extern void  ImageResize(Image *image, int newWidth, int newHeight);
extern void  ImageResizeNN(Image *image, int newWidth, int newHeight);
extern void  ImageCrop(Image *image, Rectangle crop);
extern void  ImageFlipHorizontal(Image *image);
extern void  ImageFlipVertical(Image *image);
extern void  ImageDrawPixel(Image *dst, int posX, int posY, Color color);
extern Color GetImageColor(Image image, int x, int y);
extern Texture2D LoadTextureFromImage(Image image);

void flan_rl_load_image(const char *path, long long n, Image *out) {
  char buf[PATH_MAX];
  *out = LoadImage(cstr(path, n, buf, sizeof buf));
}

bool flan_rl_is_image_valid(const Image *image) { return IsImageValid(*image); }
void flan_rl_unload_image(const Image *image)   { UnloadImage(*image); }

bool flan_rl_export_image(const Image *image, const char *path, long long n) {
  char buf[PATH_MAX];
  return ExportImage(*image, cstr(path, n, buf, sizeof buf));
}

void flan_rl_gen_image_color(int width, int height, const Color *color,
                             Image *out) {
  *out = GenImageColor(width, height, *color);
}

void flan_rl_image_resize(Image *image, int w, int h)    { ImageResize(image, w, h); }
void flan_rl_image_resize_nn(Image *image, int w, int h) { ImageResizeNN(image, w, h); }

void flan_rl_image_crop(Image *image, const Rectangle *crop) {
  ImageCrop(image, *crop);
}

void flan_rl_image_flip_horizontal(Image *image) { ImageFlipHorizontal(image); }
void flan_rl_image_flip_vertical(Image *image)   { ImageFlipVertical(image); }

void flan_rl_image_draw_pixel(Image *dst, int x, int y, const Color *color) {
  ImageDrawPixel(dst, x, y, *color);
}

void flan_rl_get_image_color(const Image *image, int x, int y, Color *out) {
  *out = GetImageColor(*image, x, y);
}

void flan_rl_load_texture_from_image(const Image *image, Texture2D *out) {
  *out = LoadTextureFromImage(*image);
}

/* ── Shapes, text and timing ─────────────────────────────────────────
 *
 * All of the drawing below needs a GL context and therefore a window, so none
 * of it can be in the acceptance table — it is exercised by running sand.flan
 * and looking. The three prototypes most likely to be remembered wrong were
 * checked against nm -D on libraylib.so.550 rather than against a header:
 * raylib 5.5 moved the line thickness off DrawRectangleRoundedLines onto
 * DrawRectangleRoundedLinesEx, so the four-argument form here is the 5.5 one
 * and not the 5.1 one.
 *
 * MeasureText, GetFrameTime, GetTime and GetScreenWidth/Height need no GL
 * context but do need InitWindow: the first reads the default font, which
 * only InitWindow loads, and the others read window state. Headless they all
 * answer 0 — measured, not assumed — so they are no more assertable than the
 * drawing is.
 */

extern void DrawPixel(int posX, int posY, Color color);
extern void DrawPixelV(Vector2 position, Color color);
extern void DrawLine(int startPosX, int startPosY, int endPosX, int endPosY,
                     Color color);
extern void DrawLineV(Vector2 startPos, Vector2 endPos, Color color);
extern void DrawLineEx(Vector2 startPos, Vector2 endPos, float thick, Color color);
extern void DrawCircle(int centerX, int centerY, float radius, Color color);
extern void DrawCircleV(Vector2 center, float radius, Color color);
extern void DrawCircleLines(int centerX, int centerY, float radius, Color color);
extern void DrawCircleLinesV(Vector2 center, float radius, Color color);
extern void DrawEllipse(int centerX, int centerY, float radiusH, float radiusV,
                        Color color);
extern void DrawEllipseLines(int centerX, int centerY, float radiusH,
                             float radiusV, Color color);
extern void DrawRing(Vector2 center, float innerRadius, float outerRadius,
                     float startAngle, float endAngle, int segments, Color color);
extern void DrawRingLines(Vector2 center, float innerRadius, float outerRadius,
                          float startAngle, float endAngle, int segments,
                          Color color);
extern void DrawTriangle(Vector2 v1, Vector2 v2, Vector2 v3, Color color);
extern void DrawTriangleLines(Vector2 v1, Vector2 v2, Vector2 v3, Color color);
extern void DrawRectangleV(Vector2 position, Vector2 size, Color color);
extern void DrawRectangleRec(Rectangle rec, Color color);
extern void DrawRectangleLines(int posX, int posY, int width, int height,
                               Color color);
extern void DrawRectangleLinesEx(Rectangle rec, float lineThick, Color color);
extern void DrawRectangleRounded(Rectangle rec, float roundness, int segments,
                                 Color color);
extern void DrawRectangleRoundedLines(Rectangle rec, float roundness,
                                      int segments, Color color);
extern void DrawRectangleRoundedLinesEx(Rectangle rec, float roundness,
                                        int segments, float lineThick,
                                        Color color);
extern void DrawText(const char *text, int posX, int posY, int fontSize,
                     Color color);
extern int  MeasureText(const char *text, int fontSize);
extern float  GetFrameTime(void);
extern double GetTime(void);
extern int    GetScreenWidth(void);
extern int    GetScreenHeight(void);

void flan_rl_draw_pixel(int x, int y, const Color *c) { DrawPixel(x, y, *c); }

void flan_rl_draw_pixel_v(const Vector2 *p, const Color *c) {
  DrawPixelV(*p, *c);
}

void flan_rl_draw_line(int x1, int y1, int x2, int y2, const Color *c) {
  DrawLine(x1, y1, x2, y2, *c);
}

void flan_rl_draw_line_v(const Vector2 *a, const Vector2 *b, const Color *c) {
  DrawLineV(*a, *b, *c);
}

void flan_rl_draw_line_ex(const Vector2 *a, const Vector2 *b, float thick,
                          const Color *c) {
  DrawLineEx(*a, *b, thick, *c);
}

void flan_rl_draw_circle(int x, int y, float radius, const Color *c) {
  DrawCircle(x, y, radius, *c);
}

void flan_rl_draw_circle_v(const Vector2 *center, float radius, const Color *c) {
  DrawCircleV(*center, radius, *c);
}

void flan_rl_draw_circle_lines(int x, int y, float radius, const Color *c) {
  DrawCircleLines(x, y, radius, *c);
}

void flan_rl_draw_circle_lines_v(const Vector2 *center, float radius,
                                 const Color *c) {
  DrawCircleLinesV(*center, radius, *c);
}

void flan_rl_draw_ellipse(int x, int y, float rh, float rv, const Color *c) {
  DrawEllipse(x, y, rh, rv, *c);
}

void flan_rl_draw_ellipse_lines(int x, int y, float rh, float rv, const Color *c) {
  DrawEllipseLines(x, y, rh, rv, *c);
}

void flan_rl_draw_ring(const Vector2 *center, float inner, float outer,
                       float start, float end, int segments, const Color *c) {
  DrawRing(*center, inner, outer, start, end, segments, *c);
}

void flan_rl_draw_ring_lines(const Vector2 *center, float inner, float outer,
                             float start, float end, int segments,
                             const Color *c) {
  DrawRingLines(*center, inner, outer, start, end, segments, *c);
}

void flan_rl_draw_triangle(const Vector2 *a, const Vector2 *b, const Vector2 *d,
                           const Color *c) {
  DrawTriangle(*a, *b, *d, *c);
}

void flan_rl_draw_triangle_lines(const Vector2 *a, const Vector2 *b,
                                 const Vector2 *d, const Color *c) {
  DrawTriangleLines(*a, *b, *d, *c);
}

void flan_rl_draw_rectangle_v(const Vector2 *position, const Vector2 *size,
                              const Color *c) {
  DrawRectangleV(*position, *size, *c);
}

void flan_rl_draw_rectangle_rec(const Rectangle *rec, const Color *c) {
  DrawRectangleRec(*rec, *c);
}

void flan_rl_draw_rectangle_lines(int x, int y, int w, int h, const Color *c) {
  DrawRectangleLines(x, y, w, h, *c);
}

void flan_rl_draw_rectangle_lines_ex(const Rectangle *rec, float thick,
                                     const Color *c) {
  DrawRectangleLinesEx(*rec, thick, *c);
}

void flan_rl_draw_rectangle_rounded(const Rectangle *rec, float roundness,
                                    int segments, const Color *c) {
  DrawRectangleRounded(*rec, roundness, segments, *c);
}

/* Four arguments, not five: 5.5's DrawRectangleRoundedLines has no thickness
 * and the Ex variant below is where it went. Getting this wrong links fine. */
void flan_rl_draw_rectangle_rounded_lines(const Rectangle *rec, float roundness,
                                          int segments, const Color *c) {
  DrawRectangleRoundedLines(*rec, roundness, segments, *c);
}

void flan_rl_draw_rectangle_rounded_lines_ex(const Rectangle *rec,
                                             float roundness, int segments,
                                             float thick, const Color *c) {
  DrawRectangleRoundedLinesEx(*rec, roundness, segments, thick, *c);
}

void flan_rl_draw_text(const char *text, long long n, int x, int y,
                       int font_size, const Color *c) {
  char buf[512];
  DrawText(cstr(text, n, buf, sizeof buf), x, y, font_size, *c);
}

int flan_rl_measure_text(const char *text, long long n, int font_size) {
  char buf[512];
  return MeasureText(cstr(text, n, buf, sizeof buf), font_size);
}

float  flan_rl_get_frame_time(void)    { return GetFrameTime(); }
double flan_rl_get_time(void)          { return GetTime(); }
int    flan_rl_get_screen_width(void)  { return GetScreenWidth(); }
int    flan_rl_get_screen_height(void) { return GetScreenHeight(); }