logging.h

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/**
 * @file logging.h
 * @brief Logging utilities and macros for PETSc-based applications.
 *
 * This header defines logging levels, scopes, and macros for consistent logging throughout the application.
 * It provides functions to retrieve the current logging level and macros to simplify logging with scope control.
 */
 
#ifndef LOGGING_H
#define LOGGING_H
 
// Include necessary headers
#include <petsc.h>   // PETSc library header
#include <stdlib.h>
#include <string.h>
#include <petscsys.h>
#include <ctype.h>
#include "variables.h"
#include "Boundaries.h"
// --------------------- Logging Levels Definition ---------------------
 
/**
 * @brief Enumeration of logging levels.
 *
 * Defines various severity levels for logging messages.
 */
typedef enum {
    LOG_ERROR = 0,   /**< Critical errors that may halt the program */
    LOG_WARNING,     /**< Non-critical issues that warrant attention */
    LOG_PROFILE,      /**< Exclusive log level for performance timing and profiling */
    LOG_INFO,        /**< Informational messages about program execution */
    LOG_DEBUG,       /**< Detailed debugging information */
    LOG_TRACE,        /**< Very fine-grained tracing information for in-depth debugging */
    LOG_VERBOSE      /**< Extremely detailed logs, typically for development use only */
} LogLevel;
 
// -------------------- Logging Scope Definitions ------------------
 
/**
 * @brief Logging scope definitions for controlling message output.
 *
 * - LOCAL: Logs on the current process using MPI_COMM_SELF.
 * - GLOBAL: Logs across all processes using MPI_COMM_WORLD.
 */
#define LOCAL  0  ///< Scope for local logging on the current process.
#define GLOBAL 1  ///< Scope for global logging across all processes.
 
//----------------------- Custom KSP Monitor Struct ------------
 
/**
 * @brief Context for a dual-purpose KSP monitor.
 *
 * This struct holds a file viewer for unconditional logging and a boolean
 * flag to enable/disable optional logging to the console.
 */
typedef struct {
    FILE        *file_handle;        // C file handling for logging.
    PetscBool   log_to_console;   // Flag to enable console output.
    PetscReal   bnorm;            // Stores the norm of the initial RHS vector.
    PetscInt    step;             // Timestep
    PetscInt    block_id;         // the ID of the block this monitor is for.   
} DualMonitorCtx;
 
// --------------------- Logging Macros ---------------------
 
/**
 * @brief Logging macro for PETSc-based applications with scope control.
 *
 * This macro provides a convenient way to log messages with different scopes
 * (LOCAL or GLOBAL) and severity levels. It utilizes PETSc's `PetscPrintf` 
 * function for message output.
 *
 * @param scope Specifies the logging scope:
 *              - LOCAL: Logs on the current process using MPI_COMM_SELF.
 *              - GLOBAL: Logs on all processes using MPI_COMM_WORLD.
 * @param level The severity level of the message (e.g., LOG_INFO, LOG_ERROR).
 * @param fmt   The format string for the message (similar to printf).
 * @param ...   Additional arguments for the format string (optional).
 *
 * Example usage:
 *     LOG(LOCAL, LOG_ERROR, "An error occurred at index %ld.\n", idx);
 *     LOG(GLOBAL, LOG_INFO, "Grid size: %ld x %ld x %ld.\n", nx, ny, nz);
 */
#define LOG(scope, level, fmt, ...) \
    do { \
        /* Determine the MPI communicator based on the scope */ \
        MPI_Comm comm = (scope == LOCAL) ? MPI_COMM_SELF : MPI_COMM_WORLD; \
        /* Check if the log level is within the allowed range */ \
        if ((int)(level) <= (int)get_log_level()) { \
            /* Print the message to the specified communicator */ \
            PetscPrintf(comm, fmt, ##__VA_ARGS__); \
        } \
    } while (0)
 
/**
 * @brief Default logging macro for PETSc-based applications.
 *
 * This macro simplifies logging by defaulting the scope to GLOBAL
 * (i.e., `MPI_COMM_WORLD`) and providing a convenient interface for
 * common logging needs.
 *
 * @param level The severity level of the message (e.g., LOG_ERROR, LOG_INFO).
 * @param fmt   The format string for the log message (similar to printf).
 * @param ...   Additional arguments for the format string (optional).
 *
 * Example usage:
 *     LOG_DEFAULT(LOG_ERROR, "Error occurred at index %ld.\n", idx);
 *     LOG_DEFAULT(LOG_INFO, "Grid size: %ld x %ld x %ld.\n", nx, ny, nz);
 *
 * @note
 * - By default, this macro logs across all MPI processes using `MPI_COMM_WORLD`.
 * - If finer control (e.g., local logging) is required, use the more general `LOG` macro.
 * - The log level is filtered based on the value returned by `get_log_level()`.
 */
#define LOG_DEFAULT(level, fmt, ...) \
    do { \
        /* Set the communicator to global (MPI_COMM_WORLD) by default */ \
        MPI_Comm comm = MPI_COMM_WORLD; \
        /* Check if the log level is within the allowed range */ \
        if ((int)(level) <= (int)get_log_level()) { \
            /* Print the message using PetscPrintf with the global communicator */ \
            PetscPrintf(comm, fmt, ##__VA_ARGS__); \
        } \
    } while (0)
 
/**
 * @brief Logging macro for PETSc-based applications with scope control, 
 *        using synchronized output across processes.
 *
 * This macro uses `PetscSynchronizedPrintf` and `PetscSynchronizedFlush` to 
 * ensure messages from different ranks are printed in a synchronized (rank-by-rank) 
 * manner, preventing interleaved outputs.
 *
 * @param scope Specifies the logging scope:
 *              - LOCAL:  Logs on the current process using MPI_COMM_SELF.
 *              - GLOBAL: Logs on all processes using MPI_COMM_WORLD.
 * @param level The severity level of the message (e.g., LOG_INFO, LOG_ERROR).
 * @param fmt   The format string for the message (similar to printf).
 * @param ...   Additional arguments for the format string (optional).
 *
 * Example usage:
 *     LOG_SYNC(LOCAL, LOG_ERROR, "An error occurred at index %ld.\n", idx);
 *     LOG_SYNC(GLOBAL, LOG_INFO, "Synchronized info: rank = %ld.\n", rank);
 */
#define LOG_SYNC(scope, level, fmt, ...) \
    do { \
        /* Determine the MPI communicator based on the scope */ \
        MPI_Comm comm = (scope == LOCAL) ? MPI_COMM_SELF : MPI_COMM_WORLD; \
        /* Check if the log level is within the allowed range */ \
        if ((int)(level) <= (int)get_log_level()) { \
            /* Synchronized print (collective) on the specified communicator */ \
            PetscSynchronizedPrintf(comm, fmt, ##__VA_ARGS__); \
            /* Ensure all ranks have finished printing before continuing */ \
            PetscSynchronizedFlush(comm, PETSC_STDOUT); \
        } \
    } while (0)
 
/**
 * @brief Default synchronized logging macro for PETSc-based applications.
 *
 * This macro simplifies logging by defaulting the scope to GLOBAL 
 * (i.e., `MPI_COMM_WORLD`) and provides synchronized output across 
 * all processes.
 *
 * @param level The severity level of the message (e.g., LOG_ERROR, LOG_INFO).
 * @param fmt   The format string for the log message (similar to printf).
 * @param ...   Additional arguments for the format string (optional).
 *
 * Example usage:
 *     LOG_SYNC_DEFAULT(LOG_ERROR, "Error at index %ld.\n", idx);
 *     LOG_SYNC_DEFAULT(LOG_INFO,  "Process rank: %ld.\n", rank);
 *
 * @note
 * - By default, this macro logs across all MPI processes using `MPI_COMM_WORLD`.
 * - If local (per-process) logging is required, use the more general `LOG_SYNC` macro.
 * - The log level is filtered based on the value returned by `get_log_level()`.
 */
#define LOG_SYNC_DEFAULT(level, fmt, ...) \
    do { \
        if ((int)(level) <= (int)get_log_level()) { \
            PetscSynchronizedPrintf(MPI_COMM_WORLD, fmt, ##__VA_ARGS__); \
            PetscSynchronizedFlush(MPI_COMM_WORLD, PETSC_STDOUT); \
        } \
    } while (0)
 
 
 
/**
 * @brief Logging macro that checks both the log level and whether the calling function
 *        is in the allowed-function list before printing. Useful for selective, per-function logging.
 *
 * @param scope Specifies the logging scope (LOCAL or GLOBAL).
 * @param level The severity level of the message (e.g., LOG_INFO, LOG_ERROR).
 * @param fmt   The format string for the message (similar to printf).
 * @param ...   Additional arguments for the format string (optional).
 *
 * Example usage:
 *     LOG_ALLOW(LOCAL, LOG_DEBUG, "Debugging info in function: %s\n", __func__);
 */
#define LOG_ALLOW(scope, level, fmt, ...) \
    do { \
        MPI_Comm comm = (scope == LOCAL) ? MPI_COMM_SELF : MPI_COMM_WORLD; \
        if ((int)(level) <= (int)get_log_level() && is_function_allowed(__func__)) { \
            PetscPrintf(comm, "[%s] " fmt, __func__, ##__VA_ARGS__); \
        } \
    } while (0)
 
 
/** ------- DEBUG ------------------------------------------
#define LOG_ALLOW(scope, level, fmt, ...) \
    do { \
        MPI_Comm comm = (scope == LOCAL) ? MPI_COMM_SELF : MPI_COMM_WORLD; \
        PetscInt __current_level_val = get_log_level(); \
        PetscBool __allowed_func_val = is_function_allowed(__func__); \
        // Print BEFORE the check  \
        if (strcmp(__func__, "LocateAllParticlesInGrid") == 0) { \
             printf("[DEBUG LOG_ALLOW in %s] Checking: level=%d, get_log_level() returned %d, func_allowed=%d\n", \
                    __func__, (int)level, (int)__current_level_val, (int)__allowed_func_val); \
        } \
        if ((int)(level) <= (int)__current_level_val && __allowed_func_val) { \
             // Print AFTER passing the check // \
             if (strcmp(__func__, "LocateAllParticlesInGrid") == 0) { \
                  printf("[DEBUG LOG_ALLOW in %s] Check PASSED. Printing log.\n", __func__); \
             } \
             PetscPrintf(comm, "[%s] " fmt, __func__, ##__VA_ARGS__); \
        } \
    } while (0)
-------------------------------------------------------------------------------
*/
 
/**
 * @brief Synchronized logging macro that checks both the log level 
 *        and whether the calling function is in the allow-list.
 *
 * This macro uses `PetscSynchronizedPrintf` and `PetscSynchronizedFlush` to
 * ensure messages from different ranks are printed in a rank-ordered fashion
 * (i.e., to avoid interleaving). It also filters out messages if the current
 * function is not in the allow-list (`is_function_allowed(__func__)`) or the
 * requested log level is higher than `get_log_level()`.
 *
 * @param scope  Either LOCAL (MPI_COMM_SELF) or GLOBAL (MPI_COMM_WORLD).
 * @param level  One of LOG_ERROR, LOG_WARNING, LOG_INFO, LOG_DEBUG.
 * @param fmt    A `printf`-style format string (e.g., "Message: %ld\n").
 * @param ...    Variadic arguments to fill in `fmt`.
 *
 * Example usage:
 *
 * \code{.c}
 * LOG_ALLOW_SYNC(LOCAL, LOG_DEBUG, "Debug info: rank = %ld\n", rank);
 * LOG_ALLOW_SYNC(GLOBAL, LOG_INFO,  "Synchronized info in %s\n", __func__);
 * \endcode
 */
/*
#define LOG_ALLOW_SYNC(scope,level, fmt, ...)                                 \
    do {                                                                       \
        if ((scope != LOCAL && scope != GLOBAL)) {                             \
            fprintf(stderr, "LOG_ALLOW_SYNC ERROR: Invalid scope at %s:%d\n",  \
                    __FILE__, __LINE__);                                       \
        } else if (is_function_allowed(__func__) &&                            \
                  (int)(level) <= (int)get_log_level()) {                      \
            MPI_Comm comm = (scope == LOCAL) ? MPI_COMM_SELF : MPI_COMM_WORLD; \
            PetscSynchronizedPrintf(comm, "[%s] " fmt, __func__, ##__VA_ARGS__); \
        }
    PetscSynchronizedFlush(comm, PETSC_STDOUT);                     \
    } while (0)
*/
#define LOG_ALLOW_SYNC(scope, level, fmt, ...)                                     \
do {                                                                               \
    /* ------------------------------------------------------------------ */      \
    /* Validate scope and pick communicator *before* any early exits.     */      \
    /* ------------------------------------------------------------------ */      \
    MPI_Comm _comm;                                                                \
    if      ((scope) == LOCAL)  _comm = MPI_COMM_SELF;                             \
    else if ((scope) == GLOBAL) _comm = MPI_COMM_WORLD;                            \
    else {                                                                        \
        fprintf(stderr, "LOG_ALLOW_SYNC ERROR: invalid scope (%d) at %s:%d\n",     \
                (scope), __FILE__, __LINE__);                                      \
        MPI_Abort(MPI_COMM_WORLD, 1);                                              \
    }                                                                              \
                                                                                   \
    /* ------------------------------------------------------------------ */      \
    /* Decide whether *this* rank should actually print.                   */      \
    /* ------------------------------------------------------------------ */      \
    PetscBool _doPrint =                                                          \
        is_function_allowed(__func__) && ((int)(level) <= (int)get_log_level());   \
                                                                                   \
    if (_doPrint) {                                                                \
        PetscSynchronizedPrintf(_comm, "[%s] " fmt, __func__, ##__VA_ARGS__);      \
    }                                                                              \
                                                                                   \
    /* ------------------------------------------------------------------ */      \
    /* ALL ranks call the flush, even if they printed nothing.            */      \
    /* ------------------------------------------------------------------ */      \
    PetscSynchronizedFlush(_comm, PETSC_STDOUT);                                   \
} while (0)
 
/**
 * @brief Logs a message inside a loop, but only every `interval` iterations.
 *
 * @param scope     LOCAL or GLOBAL.
 * @param level     LOG_* level.
 * @param iterVar   The loop variable (e.g., i).
 * @param interval  Only log when (iterVar % interval == 0).
 * @param fmt       printf-style format string.
 * @param ...       Variadic arguments to include in the formatted message.
 *
 * Example:
 *    for (int i = 0; i < 100; i++) {
 *        LOG_LOOP_ALLOW(LOCAL, LOG_DEBUG, i, 10, "Value of i=%d\n", i);
 *    }
 */
#define LOG_LOOP_ALLOW(scope, level, iterVar, interval, fmt, ...)              \
    do {                                                                       \
        if (is_function_allowed(__func__) && (int)(level) <= (int)get_log_level()) { \
            if ((iterVar) % (interval) == 0) {                                 \
                MPI_Comm comm = (scope == LOCAL) ? MPI_COMM_SELF : MPI_COMM_WORLD; \
                PetscPrintf(comm, "[%s] [%s=%d] " fmt,                       \
                            __func__, #iterVar, (iterVar), ##__VA_ARGS__);               \
            }                                                                  \
        }                                                                      \
    } while (0)
/*
#define LOG_LOOP_ALLOW(scope,level, iterVar, interval, fmt, ...)              \
    do {                                                                       \
        if (is_function_allowed(__func__) && (int)(level) <= (int)get_log_level()) { \
            if ((iterVar) % (interval) == 0) {                                 \
                MPI_Comm comm = (scope == LOCAL) ? MPI_COMM_SELF : MPI_COMM_WORLD; \
                PetscPrintf(comm, "[%s] [Iter=%d] " fmt,                       \
                            __func__, (iterVar), ##__VA_ARGS__);               \
            }                                                                  \
        }                                                                      \
    } while (0)
*/
 
/**
 * @brief Logs a custom message if a variable equals a specific value.
 *
 * This is a variadic macro for logging a single event when a condition is met.
 * It is extremely useful for printing debug information at a specific iteration
 * of a loop or when a state variable reaches a certain value.
 *
 * @param scope   Either LOCAL or GLOBAL.
 * @param level   The logging level.
 * @param var     The variable to check (e.g., a loop counter 'k').
 * @param val     The value that triggers the log (e.g., 6). The log prints if var == val.
 * @param ...     A printf-style format string and its corresponding arguments.
 */
#define LOG_LOOP_ALLOW_EXACT(scope, level, var, val, fmt, ...)                  \
    do {                                                                       \
        /* First, perform the cheap, standard gatekeeper checks. */            \
        if (is_function_allowed(__func__) && (int)(level) <= (int)get_log_level()) { \
            /* Only if those pass, check the user's specific condition. */      \
            if ((var) == (val)) {                                              \
                MPI_Comm comm = ((scope) == LOCAL) ? MPI_COMM_SELF : MPI_COMM_WORLD; \
                /* Print the standard prefix, then the user's custom message. */ \
                PetscPrintf(comm, "[%s] [%s=%d] " fmt,                          \
                    __func__, #var, (var), ##__VA_ARGS__);                      \
            }                                                                  \
        }                                                                      \
    } while (0)
 
/**
 * @brief Logs a single element of an array, given an index.
 *
 * @param scope   Either LOCAL or GLOBAL.
 * @param level   LOG_ERROR, LOG_WARNING, LOG_INFO, or LOG_DEBUG.
 * @param arr     Pointer to the array to log from.
 * @param length  The length of the array (to prevent out-of-bounds).
 * @param idx     The index of the element to print.
 * @param fmt     The printf-style format specifier (e.g. "%g", "%f", etc.).
 *
 * This macro only logs if:
 *  1) The current function is in the allow-list (`is_function_allowed(__func__)`).
 *  2) The requested logging `level` <= the current global `get_log_level()`.
 *  3) The index `idx` is valid (0 <= idx < length).
 */
#define LOG_ARRAY_ELEMENT_ALLOW(scope,level, arr, length, idx, fmt)          \
    do {                                                                      \
        if (is_function_allowed(__func__) && (int)(level) <= (int)get_log_level()) { \
            if ((idx) >= 0 && (idx) < (length)) {                             \
                MPI_Comm comm = (scope == LOCAL) ? MPI_COMM_SELF : MPI_COMM_WORLD; \
                PetscPrintf(comm, "[%s] arr[%d] = " fmt "\n",                 \
                            __func__, (idx), (arr)[idx]);                     \
            }                                                                 \
        }                                                                     \
    } while (0)
 
/**
 * @brief Logs a consecutive subrange of an array.
 *
 * @param scope   Either LOCAL or GLOBAL.
 * @param level   LOG_ERROR, LOG_WARNING, LOG_INFO, or LOG_DEBUG.
 * @param arr     Pointer to the array to log from.
 * @param length  Total length of the array.
 * @param start   Starting index of the subrange.
 * @param end     Ending index of the subrange (inclusive).
 * @param fmt     The printf-style format specifier (e.g., "%g", "%f").
 *
 * This macro prints each element arr[i] for i in [start, end], bounded by [0, length-1].
 */
#define LOG_ARRAY_SUBRANGE_ALLOW(scope,level, arr, length, start, end, fmt)  \
    do {                                                                      \
        if (is_function_allowed(__func__) && (int)(level) <= (int)get_log_level()) { \
            MPI_Comm comm = (scope == LOCAL) ? MPI_COMM_SELF : MPI_COMM_WORLD; \
            PetscInt _start = (start) < 0 ? 0 : (start);                      \
            PetscInt _end   = (end) >= (length) ? (length) - 1 : (end);       \
            for (PetscInt i = _start; i <= _end; i++) {                       \
                PetscPrintf(comm, "[%s] arr[%d] = " fmt "\n", __func__, i, (arr)[i]); \
            }                                                                 \
        }                                                                     \
    } while (0)
 
#define LOG_PROFILE_MSG(scope, fmt, ...)                                     \
    do {                                                                     \
        if ((int)(LOG_PROFILE) <= (int)get_log_level()) {                    \
            MPI_Comm comm = (scope == LOCAL) ? MPI_COMM_SELF : MPI_COMM_WORLD; \
            PetscPrintf(comm, "[PROFILE] " fmt, ##__VA_ARGS__);              \
        }                                                                    \
    } while (0)
 
// --------------------- Function Declarations ---------------------
 
/**
 * @brief Retrieves the current logging level from the environment variable `LOG_LEVEL`.
 *
 * The function checks the `LOG_LEVEL` environment variable and sets the logging level accordingly.
 * Supported levels are "DEBUG", "INFO", "WARNING", and defaults to "ERROR" if not set or unrecognized.
 *
 * @return LogLevel The current logging level.
 */
LogLevel get_log_level();
 
/**
 * @brief Prints the current logging level to the console.
 *
 * This function retrieves the log level using `get_log_level()` and prints 
 * the corresponding log level name. It helps verify the logging configuration 
 * at runtime.
 *
 * The log levels supported are:
 * - `LOG_PROFILE` (0) : Logs performance profiling details.
 * - `LOG_ERROR`   (1) : Logs only critical errors.
 * - `LOG_WARNING` (2) : Logs warnings and errors.
 * - `LOG_INFO`    (3) : Logs general information, warnings, and errors.
 * - `LOG_DEBUG`   (4) : Logs debugging information, info, warnings, and errors.
 *
 * @note The log level is determined from the `LOG_LEVEL` environment variable.
 * If `LOG_LEVEL` is not set, it defaults to `LOG_INFO`.
 *
 * @see get_log_level()
 */
PetscErrorCode print_log_level(void);
 
/**
 * @brief Sets the global list of function names that are allowed to log.
 *
 * You can replace the entire list of allowed function names at runtime.
 */
void set_allowed_functions(const char** functionList, int count);
 
/**
 * @brief Checks if a given function is in the allow-list.
 *
 * This helper is used internally by the LOG_ALLOW macro.
 */
PetscBool is_function_allowed(const char* functionName);
 
/**
 * @brief Prints the coordinates of a cell's vertices.
 *
 * This function iterates through the eight vertices of a given cell and prints their
 * coordinates. It is primarily used for debugging purposes to verify the correctness
 * of cell vertex assignments.
 *
 * @param[in]  cell     Pointer to a `Cell` structure representing the cell, containing its vertices.
 * @param[in]  rank     MPI rank for identification (useful in parallel environments).
 * @return PetscErrorCode Returns 0 to indicate successful execution. Non-zero on failure.
 *
 * @note
 * - Ensure that the `cell` pointer is not `NULL` before calling this function..
 */
PetscErrorCode LOG_CELL_VERTICES(const Cell *cell, PetscMPIInt rank);
 
/**
 * @brief Prints the signed distances to each face of the cell.
 *
 * This function iterates through the six signed distances from a point to each face of a given cell
 * and prints their values. It is primarily used for debugging purposes to verify the correctness
 * of distance calculations.
 *
 * @param[in]  d        An array of six `PetscReal` values representing the signed distances.
 *                      The indices correspond to:
 *                      - d[LEFT]: Left Face
 *                      - d[RIGHT]: Right Face
 *                      - d[BOTTOM]: Bottom Face
 *                      - d[TOP]: Top Face
 *                      - d[FRONT]: Front Face
 *                      - d[BACK]: Back Face
 *
 * @return PetscErrorCode Returns 0 to indicate successful execution. Non-zero on failure.
 *
 * @note
 * - Ensure that the `d` array is correctly populated with signed distances before calling this function.
 */
PetscErrorCode LOG_FACE_DISTANCES(PetscReal* d);
 
/**
 * @brief Prints particle fields in a table that automatically adjusts its column widths.
 *
 * This function retrieves data from the particle swarm and prints a table where the
 * width of each column is determined by the maximum width needed to display the data.
 * Only every 'printInterval'-th particle is printed.
 *
 * @param[in] user           Pointer to the UserCtx structure.
 * @param[in] printInterval  Only every printInterval‑th particle is printed.
 *
 * @return PetscErrorCode Returns 0 on success.
 */
PetscErrorCode LOG_PARTICLE_FIELDS(UserCtx* user, PetscInt printInterval);
 
/* ------------------------------------------------------------------------- */
/**
 * @brief Free an array previously returned by LoadAllowedFunctionsFromFile().
 *
 * @param[in,out] funcs Array of strings to release (may be @c NULL).
 * @param[in]     n     Number of entries in @p funcs.  Ignored if @p funcs is
 *                      @c NULL.
 *
 * @return 0 on success or a PETSc error code.
 */
PetscErrorCode FreeAllowedFunctions(char **funcs, PetscInt n);
 
/**
 * @brief Load function names from a text file.
 *
 * The file is expected to contain **one identifier per line**.  Blank lines and
 * lines whose first non‑blank character is a <tt>#</tt> are silently skipped so
 * the file can include comments.  Example:
 *
 * @code{.txt}
 * # Allowed function list
 * main
 * InitializeSimulation
 * InterpolateAllFieldsToSwarm  # inline comments are OK, too
 * @endcode
 *
 * The routine allocates memory as needed (growing an internal buffer with
 * @c PetscRealloc()) and returns the resulting array and its length to the
 * caller.  Use FreeAllowedFunctions() to clean up when done.
 *
 * @param[in]  filename  Path of the configuration file to read.
 * @param[out] funcsOut  On success, points to a freshly‑allocated array of
 *                       <tt>char*</tt> (size @p nOut).
 * @param[out] nOut      Number of valid entries in @p funcsOut.
 *
 * @return 0 on success, or a PETSc error code on failure (e.g. I/O error, OOM).
 */
PetscErrorCode LoadAllowedFunctionsFromFile(const char   filename[],
                                            char      ***funcsOut,
                                            PetscInt   *nOut);
 
 
/**
 * @brief Helper function to convert BCFace enum to a string representation.
 * @param[in] face The BCFace enum value.
 * @return Pointer to a constant string representing the face.
 */
const char* BCFaceToString(BCFace face);
 
/**
 * @brief Helper function to convert FieldInitialization to a string representation.
 * @param[in] PetscInt The FieldInitialization value.
 * @return Pointer to a constant string representing the FieldInitialization.
 */
const char* FieldInitializationToString(PetscInt FieldInitialization);
 
/**
 * @brief Helper function to convert ParticleInitialization to a string representation.
 * @param[in] PetscInt The ParticleInitialization value.
 * @return Pointer to a constant string representing the FieldInitialization.
 */
const char* ParticleInitializationToString(ParticleInitializationType ParticleInitialization);
 
/**
 * @brief Helper function to convert LES Flag to a string representation.
 * @param[in] LESModelType The LES flag value.
 * @return Pointer to a constant string representing the LES Flag.
 */
const char* LESModelToString(LESModelType LESFlag);
 
/**
 * @brief Helper function to convert Momentum Solver flag to a string representation.
 * @param[in] MomentumSolverType The Momentum Solver flag value.
 * @return Pointer to a constant string representing the MomentumSolverType.
 */
const char* MomentumSolverTypeToString(MomentumSolverType SolverFlag);
 
/**
 * @brief Helper function to convert BCType enum to a string representation.
 * @param[in] type The BCType enum value.
 * @return Pointer to a constant string representing the BC type.
 */
const char* BCTypeToString(BCType type);
 
/**
 * @brief Converts a BCHandlerType enum to its string representation.
 *
 * Provides a descriptive string for a specific boundary condition implementation strategy.
 * This is crucial for logging the exact behavior configured for a face.
 *
 * @param handler_type The BCHandlerType enum value (e.g., BC_HANDLER_WALL_NOSLIP).
 * @return A constant character string corresponding to the enum. Returns
 *         "UNKNOWN_HANDLER" if the enum value is not recognized.
 */
const char* BCHandlerTypeToString(BCHandlerType handler_type);
 
/**
 * @brief A custom KSP monitor that logs to a file and optionally to the console.
 *
 * This function unconditionally calls the standard true residual monitor to log to a
 * file viewer provided in the context. It also checks a flag in the context
* and, if true, calls the monitor again to log to standard output.
 *
 * @param ksp   The Krylov subspace context.
 * @param it    The current iteration number.
 * @param rnorm The preconditioned residual norm.
 * @param ctx   A pointer to the DualMonitorCtx structure.
 * @return      PetscErrorCode 0 on success.
 */
PetscErrorCode DualKSPMonitor(KSP ksp, PetscInt it, PetscReal rnorm, void *ctx);
 
/**
 * @brief Destroys the DualMonitorCtx.
 *
 * This function is passed to KSPMonitorSet to ensure the viewer is
 * properly destroyed and the context memory is freed when the KSP is destroyed.
 * @param Ctx a pointer to the context pointer to be destroyed
 * @return PetscErrorCode
 */
PetscErrorCode DualMonitorDestroy(void **ctx);
 
/**
 * @brief Logs continuity metrics for a single block to a file.
 *
 * This function should be called for each block, once per timestep. It opens a
 * central log file in append mode. To ensure the header is written only once,
 * it checks if it is processing block 0 on the simulation's start step.
 *
 * @param user A pointer to the UserCtx for the specific block whose metrics
 *             are to be logged. The function accesses both global (SimCtx)
 *             and local (user->...) data.
 * @return     PetscErrorCode 0 on success.
 */
PetscErrorCode LOG_CONTINUITY_METRICS(UserCtx *user);
 
/**
 * @brief A function that outputs the name of the current level in the ParticleLocation enum.
 * @param level The ParticleLocation enum value.
 * @return A constant character string corresponding to the enum. Returns
 *        "UNKNOWN_LEVEL" if the enum value is not recognized.
 */
const char* ParticleLocationStatusToString(ParticleLocationStatus level); 
 
/*================================================================================*
 *                          PROGRESS BAR UTILITY                                  *
 *================================================================================*/
 
/**
 * @brief Prints a progress bar to the console.
 *
 * This function should only be called by the root process (rank 0). It uses
 * a carriage return `\r` to overwrite the same line in the terminal, creating
 * a dynamic progress bar.
 *
 * @param step           The current step index from the loop (e.g., from 0 to N-1).
 * @param startStep      The global starting step number of the simulation.
 * @param totalSteps     The total number of steps to be run in this simulation instance.
 * @param currentTime    The current simulation time to display.
 */
void PrintProgressBar(PetscInt step, PetscInt startStep, PetscInt totalSteps, PetscReal currentTime);
 
/**
 * @brief Initializes the custom profiling system using configuration from SimCtx.
 *
 * This function sets up the internal data structures for tracking function
 * performance. It reads the list of "critical functions" from the provided
 * SimCtx and marks them for per-step logging at LOG_INFO level.
 *
 * It should be called once at the beginning of the application, after
 * CreateSimulationContext() but before the main time loop.
 *
 * @param simCtx The master simulation context, which contains the list of
 *               critical function names to always log.
 * @return PetscErrorCode
 */
PetscErrorCode ProfilingInitialize(SimCtx *simCtx);
 
PetscErrorCode ProfilingResetTimestepCounters(void);
 
/**
 * @brief Logs the performance summary for the current timestep and resets timers.
 *
 * Depending on the current log level, this function will print:
 * - LOG_PROFILE: Timings for ALL functions called during the step.
 * - LOG_INFO/LOG_DEBUG: Timings for only the "always log" functions.
 *
 * It must be called once per timestep, typically at the end of the main loop.
 * After logging, it resets the per-step counters and timers.
 *
 * @param step The current simulation step number, for logging context.
 * @return PetscErrorCode
 */
PetscErrorCode ProfilingLogTimestepSummary(PetscInt step);
 
 
/**
 * @brief the profiling excercise and build a profiling summary which is then printed to a log file.
 * 
 * @param simCtx  The Simulation Context Structure that can contains all the data regarding the simulation.
 * 
 * @return        PetscErrorCode 0 on success.
 */
PetscErrorCode ProfilingFinalize(SimCtx *simCtx);
 
// --- Internal functions, do not call directly ---
// These are called by the macros below.
void _ProfilingStart(const char *func_name);
void _ProfilingEnd(const char *func_name);
 
 
/**
 * @brief Marks the beginning of a profiled code block (typically a function).
 *
 * Place this macro at the very beginning of a function you wish to profile.
 * It automatically captures the function's name and starts a wall-clock timer.
 */
#define PROFILE_FUNCTION_BEGIN \
    _ProfilingStart(__FUNCT__)
 
/**
 * @brief Marks the end of a profiled code block.
 *
 * Place this macro just before every return point in a function that starts
 * with PROFILE_FUNCTION_BEGIN. It stops the timer and accumulates the results.
 */
#define PROFILE_FUNCTION_END \
    _ProfilingEnd(__FUNCT__)
 
 
/**
 * @brief Computes and logs the local and global min/max values of a 3-component vector field.
 *
 * This utility function inspects a PETSc Vec associated with a DMDA and calculates the
 * minimum and maximum values for each of its three components (e.g., x, y, z) both for the
 * local data on the current MPI rank and for the entire global domain.
 *
 * It uses the same "smart" logic as the flow solver, ignoring the padding nodes at the
 * IM, JM, and KM boundaries of the grid. The results are printed to the standard output
 * in a formatted, easy-to-read table.
 *
 * @param[in] user      Pointer to the user-defined context. Used for grid information (IM, JM, KM)
 *                      and MPI rank.
 * @param[in] fieldName A string descriptor for the field being analyzed (e.g., "Velocity",
 *                      "Coordinates"). This is used for clear log output.
 *
 * @return PetscErrorCode Returns 0 on success, non-zero on failure.
 */
PetscErrorCode LOG_FIELD_MIN_MAX(UserCtx *user, const char *fieldName);
 
/**
 * @brief Logs the anatomy of a specified field at key boundary locations,
 *        respecting the solver's specific grid and variable architecture.
 *
 * This intelligent diagnostic function inspects a PETSc Vec and prints its values
 * at critical boundary locations (-Xi/+Xi, -Eta/+Eta, -Zeta/+Zeta). It is "architecture-aware":
 *
 * - **Cell-Centered Fields ("Ucat", "P"):** It correctly applies the "Shifted Index Architecture,"
 *   where the value for geometric `Cell i` is stored at array index `i+1`. It labels
 *   the output to clearly distinguish between true physical values and ghost values.
 * - **Face-Centered Fields ("Ucont"):** It uses a direct index mapping, where the value for
 *   the face at `Node i` is stored at index `i`.
 * - **Node-Centered Fields ("Coordinates"):** It uses a direct index mapping, where the value for
 *   `Node i` is stored at index `i`.
 *
 * The output is synchronized across MPI ranks to ensure readability and focuses on a
 * slice through the center of the domain to be concise.
 *
 * @param user       A pointer to the UserCtx structure containing the DMs and Vecs.
 * @param field_name A string identifier for the field to log (e.g., "Ucat", "P", "Ucont", "Coordinates").
 * @param stage_name A string identifier for the current simulation stage (e.g., "After Advection").
 * @return           PetscErrorCode Returns 0 on success, non-zero on failure.
 */
PetscErrorCode LOG_FIELD_ANATOMY(UserCtx *user, const char *field_name, const char *stage_name);
 
/**
@brief Logs the interpolation error between the analytical and computed solutions.
*/
PetscErrorCode LOG_INTERPOLATION_ERROR(UserCtx *user);
 
/**
 * @brief Computes advanced particle statistics and stores them in SimCtx.
 *
 * This function calculates:
 * - Particle load imbalance across MPI ranks.
 * - The total number of grid cells occupied by at least one particle.
 *
 * It requires that CalculateParticleCountPerCell() has been called prior to its
 * execution. It uses collective MPI operations and must be called by all ranks.
 *
 * @param user Pointer to the UserCtx.
 * @return     PetscErrorCode 0 on success.
 */
PetscErrorCode CalculateAdvancedParticleMetrics(UserCtx *user);
 
/**
 * @brief Logs particle swarm metrics, adapting its behavior based on a boolean flag in SimCtx.
 *
 * This function serves a dual purpose:
 * 1. If simCtx->isInitializationPhase is PETSC_TRUE, it logs settlement
 *    diagnostics to "Initialization_Metrics.log", using the provided stageName.
 * 2. If simCtx->isInitializationPhase is PETSC_FALSE, it logs regular
 *    timestep metrics to "Particle_Metrics.log".
 *
 * @param user      A pointer to the UserCtx.
 * @param stageName A descriptive string for the initialization stage (ignored in timestep mode).
 * @return          PetscErrorCode 0 on success.
 */
PetscErrorCode LOG_PARTICLE_METRICS(UserCtx *user, const char *stageName);
#endif // LOGGING_H