// C ABI for the current-flow solver (csolv): opaque doc, pipeline, mesh accessors, progress callback.
#pragma once

#include <stddef.h>

#ifdef __cplusplus
extern "C" {
#endif

typedef struct FemmCurrDoc FemmCurrDoc;

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

// lifetime
FemmCurrDoc* femm_curr_doc_new(void);
void         femm_curr_doc_free(FemmCurrDoc* doc);

// progress reporting routed to the host (Rust/Iced).
void         femm_curr_doc_set_progress(FemmCurrDoc* doc, FemmCurrProgressFn fn, void* user);

// pipeline. each returns 1 on success, 0 on failure.
int femm_curr_doc_load_fec     (FemmCurrDoc* doc, const char* path);
int femm_curr_doc_load_mesh    (FemmCurrDoc* doc);
int femm_curr_doc_renumber     (FemmCurrDoc* doc);
int femm_curr_doc_solve        (FemmCurrDoc* doc);
int femm_curr_doc_write_results(FemmCurrDoc* doc, const char* out_path);

// problem attributes after load_fec.
double femm_curr_doc_frequency    (const FemmCurrDoc* doc);
int    femm_curr_doc_axisymmetric (const FemmCurrDoc* doc);
double femm_curr_doc_depth        (const FemmCurrDoc* doc);
double femm_curr_doc_precision    (const FemmCurrDoc* doc);

// mesh, valid after load_mesh + renumber.
int  femm_curr_doc_num_nodes    (const FemmCurrDoc* doc);
void femm_curr_doc_node         (const FemmCurrDoc* doc, int i, double* x, double* y);
int  femm_curr_doc_num_elements (const FemmCurrDoc* doc);
void femm_curr_doc_element      (const FemmCurrDoc* doc, int i, int* p0, int* p1, int* p2);

// property table sizes.
int femm_curr_doc_num_materials  (const FemmCurrDoc* doc);
int femm_curr_doc_num_boundaries (const FemmCurrDoc* doc);
int femm_curr_doc_num_conductors (const FemmCurrDoc* doc);

// field-point sampling after solve. component selects which scalar to fetch.
typedef enum {
    FEMM_CURR_FIELD_V_RE     = 0,
    FEMM_CURR_FIELD_V_IM     = 1,
    FEMM_CURR_FIELD_EX_RE    = 2,
    FEMM_CURR_FIELD_EX_IM    = 3,
    FEMM_CURR_FIELD_EY_RE    = 4,
    FEMM_CURR_FIELD_EY_IM    = 5,
    FEMM_CURR_FIELD_E_MAG_RE = 6,
    FEMM_CURR_FIELD_E_MAG_IM = 7,
    FEMM_CURR_FIELD_JX_RE    = 8,
    FEMM_CURR_FIELD_JX_IM    = 9,
    FEMM_CURR_FIELD_JY_RE    = 10,
    FEMM_CURR_FIELD_JY_IM    = 11,
    FEMM_CURR_FIELD_J_MAG_RE = 12,
    FEMM_CURR_FIELD_J_MAG_IM = 13,
} FemmCurrField;

double femm_curr_doc_field_at(const FemmCurrDoc* doc, double x, double y, FemmCurrField component);

#ifdef __cplusplus
}
#endif