// C ABI for the electrostatic solver (belasolv): opaque doc, pipeline, mesh accessors, progress callback.
#pragma once

#include <stddef.h>

#ifdef __cplusplus
extern "C" {
#endif

typedef struct FemmElecDoc FemmElecDoc;

// pct in 0..100, or -1 for label-only updates. label may be NULL.
typedef void (*FemmElecProgressFn)(int pct, const char* label, void* user);

// lifetime
FemmElecDoc* femm_elec_doc_new(void);
void         femm_elec_doc_free(FemmElecDoc* doc);

// progress reporting routed to the host (Rust/Iced).
void         femm_elec_doc_set_progress(FemmElecDoc* doc, FemmElecProgressFn fn, void* user);

// pipeline. each returns 1 on success, 0 on failure.
int femm_elec_doc_load_fee     (FemmElecDoc* doc, const char* path);
int femm_elec_doc_load_mesh    (FemmElecDoc* doc);
int femm_elec_doc_renumber     (FemmElecDoc* doc);
int femm_elec_doc_solve        (FemmElecDoc* doc);
int femm_elec_doc_write_results(FemmElecDoc* doc, const char* out_path);

// problem attributes after load_fee.
int    femm_elec_doc_axisymmetric (const FemmElecDoc* doc);
double femm_elec_doc_depth        (const FemmElecDoc* doc);
double femm_elec_doc_precision    (const FemmElecDoc* doc);

// mesh, valid after load_mesh + renumber.
int  femm_elec_doc_num_nodes    (const FemmElecDoc* doc);
void femm_elec_doc_node         (const FemmElecDoc* doc, int i, double* x, double* y);
int  femm_elec_doc_num_elements (const FemmElecDoc* doc);
void femm_elec_doc_element      (const FemmElecDoc* doc, int i, int* p0, int* p1, int* p2);

// property table sizes.
int femm_elec_doc_num_materials  (const FemmElecDoc* doc);
int femm_elec_doc_num_boundaries (const FemmElecDoc* doc);
int femm_elec_doc_num_conductors (const FemmElecDoc* doc);

// field-point sampling after solve. component selects which scalar to fetch.
typedef enum {
    FEMM_ELEC_FIELD_V     = 0,
    FEMM_ELEC_FIELD_EX    = 1,
    FEMM_ELEC_FIELD_EY    = 2,
    FEMM_ELEC_FIELD_E_MAG = 3,
    FEMM_ELEC_FIELD_DX    = 4,
    FEMM_ELEC_FIELD_DY    = 5,
    FEMM_ELEC_FIELD_D_MAG = 6,
} FemmElecField;

double femm_elec_doc_field_at(const FemmElecDoc* doc, double x, double y, FemmElecField component);

#ifdef __cplusplus
}
#endif