// Course Plotter (FS2 64K-only feature, chunk2 lines 25-150).
//
// FS2's `CoursePlotterState` is one of three values:
//   0 = OFF, 1 = RECORD, 2 = DISPLAY
//
// In RECORD mode the simulator samples the aircraft's position every
// `sampleRate` frames into a circular buffer ($D000-$DFFF in the
// language card). DISPLAY mode redraws the recorded course in the
// radar viewport.
//
// The C port keeps the same state machine but stores samples in an
// in-process buffer (4KB) rather than the LC bank. Recording uses
// either NORMAL (range=$06, rate=$0A) or PRECISION (range=$04, rate=$02)
// per FS2 chunk2 BeginNormalCourseRecording / BeginPrecisionRecording.

#ifndef COURSE_PLOTTER_H
#define COURSE_PLOTTER_H

#include <stdbool.h>
#include <stdint.h>

struct AircraftT;
struct FramebufferT;

typedef enum CoursePlotterStateE {
        COURSE_PLOT_OFF     = 0,
        COURSE_PLOT_RECORD  = 1,
        COURSE_PLOT_DISPLAY = 2
} CoursePlotterStateE;

#define COURSE_PLOT_BUFFER_BYTES    4096
#define COURSE_PLOT_SAMPLE_BYTES    8       // 2 * 24-bit XYZ rounded up


typedef struct CoursePlotterT {
        CoursePlotterStateE state;
        uint8_t  sampleRate;       // frames between samples (chunk2: $0A normal, $02 precision)
        uint8_t  sampleRange;      // chunk2 sampleRange byte
        uint8_t  sampleCounter;    // counts down to 0, then take a sample
        bool     anyData;          // true once a sample has been captured
        uint16_t recordPos;        // byte offset into buffer
        uint8_t  buffer[COURSE_PLOT_BUFFER_BYTES];
} CoursePlotterT;


void coursePlotterInit(CoursePlotterT *cp);

// Begin a recording session. Mode must be RECORD or OFF; precision
// chooses between normal (rate 10/range 6) and precision (rate 2/range 4).
void coursePlotterBeginRecord(CoursePlotterT *cp, bool precision);

void coursePlotterBeginDisplay(CoursePlotterT *cp);
void coursePlotterTurnOff(CoursePlotterT *cp);

// Per-frame: if state == RECORD, count down sampleCounter and snapshot
// the aircraft's scenery position into the buffer when it hits 0.
void coursePlotterStep(CoursePlotterT *cp, const struct AircraftT *ac);

// Render the recorded course on top of the framebuffer (called when
// state == DISPLAY in radar/3D view).
void coursePlotterRender(const CoursePlotterT *cp, struct FramebufferT *fb,
                         const struct AircraftT *ac);

// Draw a short status line ("COURSE PLOT REC" / "COURSE PLOT VIEW")
// when the plotter is active. No-op when off.
void coursePlotterDrawStatus(const CoursePlotterT *cp, struct FramebufferT *fb);

#endif