#ifndef PGXP_H
#define PGXP_H

/* PGXP value-propagation engine — runtime-internal API (pgxp.cpp).
 *
 * The engine shadows every 32-bit word of guest RAM/scratchpad, every GPR,
 * and every GTE data register with the sub-pixel projection it carries
 * (screen X/Y in 16.16 plus the projected SZ depth). The GTE fills shadows at
 * RTPS/RTPT; the psx_pgxp_* hooks (pgxp_hooks.h) move them along with the
 * data; the GPU asks for the precise position of each GP0 vertex word by the
 * packet's RAM address, validated against the actual word — never guessed
 * from the rounded position (the measured G1.4 dead end).
 *
 * Guest-visible state is NEVER touched: shadows are host-only, dropped on
 * savestate/rewind, and suppressed during speculative validation passes.
 */

#include <stdint.h>

#ifdef __cplusplus
extern "C" {
#endif

/* --- lifecycle / configuration ------------------------------------------ */

/* Master arm. Allocates the RAM shadow lazily; fails closed (stays disabled)
 * if the allocation fails. Idempotent. */
void pgxp_set_enabled(int enabled);
int  pgxp_enabled(void);

/* Tier-2 propagation through CPU arithmetic (default off, like the reference
 * implementations' default). Off is SAFE — value validation already stops
 * stale shadows — it only bounds coverage. Live-tunable (TCP). */
void pgxp_set_cpu_mode(int enabled);
int  pgxp_cpu_mode(void);

/* Reject a precise position whose sub-pixel offset from the native integer
 * position exceeds this many pixels. < 0 disables the clamp (default). */
void  pgxp_set_tolerance(float pixels);
float pgxp_tolerance(void);

/* Drop all shadows (savestate load, raw RAM restore, timeline breaks).
 * O(1) via generation bump. Deferred while suppressed. */
void pgxp_invalidate_all(void);

/* Counted suppression bracket for speculative native-validation passes and
 * the GTE replay sandbox: hooks and producers no-op inside it. */
void pgxp_suppress_begin(void);
void pgxp_suppress_end(void);

/* --- GTE producer (gte.cpp) ---------------------------------------------- */

/* Called at the RTPS/RTPT projection with the pre-truncation 16.16 screen
 * coordinates, the projected depth (SZ3), and the packed SXY word the guest
 * sees. Shifts the shadow FIFO exactly like push_sxy (regs 12..15). */
void pgxp_gte_push_sxy(int32_t x16, int32_t y16, uint16_t sz3, uint32_t packed);

/* Guest write to a GTE data register outside gte_execute (MTC2/CTC2 handled
 * by psx_pgxp_cop2; this is for direct gte_write_data paths): reg 15 performs
 * the SXYP FIFO push on the shadows, others just invalidate/overwrite. */
void pgxp_gte_reg_written(int reg, uint32_t value);

/* --- GPU consumer (gpu.c) ------------------------------------------------ */

enum {
    PGXP_SRC_NATIVE   = 0,   /* no shadow — caller uses the parsed integers  */
    PGXP_SRC_FALLBACK = 1,   /* position-cache fallback (never carries depth)*/
    PGXP_SRC_DATAFLOW = 2,   /* address-keyed shadow, value-validated        */
};

/* Precise position for one GP0 vertex word.
 *   addr        guest address the word was DMA'd from, or 0xFFFFFFFF if
 *               unknown (immediate GP0 writes) — skips the dataflow tier.
 *   packet_word the actual word (validation key).
 *   int_x/int_y the natively parsed 11-bit positions (pre-draw-offset).
 * On DATAFLOW/FALLBACK, *x16/*y16 hold the sub-pixel position (16.16, same
 * coordinate space as the packet halves); *sz is the projected depth or 0.
 * Safeguards applied here: the integer part must match the native parse
 * (truncation agreement) and the tolerance clamp. */
int pgxp_get_precise_vertex(uint32_t addr, uint32_t packet_word,
                            int32_t int_x, int32_t int_y,
                            int32_t *x16, int32_t *y16, uint16_t *sz);

/* --- observability -------------------------------------------------------- */

typedef struct PGXPStats {
    uint64_t lookups;            /* pgxp_get_precise_vertex calls            */
    uint64_t dataflow_hit;
    uint64_t fallback_hit;
    uint64_t native;
    uint64_t value_mismatch;     /* shadow present but wrong word (stale)    */
    uint64_t trunc_reject;       /* integer part disagreed with native parse */
    uint64_t tolerance_reject;
    uint64_t w_valid;            /* lookups that also carried a usable depth */
    uint64_t produced;           /* RTPS/RTPT projections pushed into shadows */
    uint64_t swc2_stores;        /* GTE reg shadows copied to RAM shadows     */
} PGXPStats;

void pgxp_get_stats(PGXPStats *out);

/* --- gte.cpp forwarding surface (v14 ABI compat) -------------------------- */

/* SWC2 site: copy the GTE register shadow (regs 12..15) to the RAM shadow. */
void pgxp_store_gte_reg(uint32_t addr, uint8_t reg);

/* Address-keyed precise-word lookup (perspective texturing path). Returns
 * nonzero when the tracked word matches `packed` AND carries a depth. */
int pgxp_load_precise_word(uint32_t addr, uint32_t packed,
                           int32_t *x16, int32_t *y16, uint16_t *z);

/* --- test accessors (always compiled; trivial) ---------------------------- */

/* index 0..3 selects the SXY0..SXYP register shadow (GTE data regs 12..15). */
void pgxp_test_seed_gte_sxy(uint32_t index, uint32_t packed,
                            int32_t x16, int32_t y16, uint16_t z, int valid);
void pgxp_test_get_gte_sxy(uint32_t index, uint32_t *packed,
                           int32_t *x16, int32_t *y16, uint16_t *z,
                           uint8_t *valid);
uint32_t pgxp_test_generation(void);
uint32_t pgxp_test_suppress_depth(void);
int      pgxp_test_active(void);
void     pgxp_test_set_generation(uint32_t gen);

#ifdef __cplusplus
}
#endif

#endif /* PGXP_H */