/*****************************************************************************
 * system include files
 ****************************************************************************/

#include <assert.h>

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>


/*****************************************************************************
 * ompt include files
 ****************************************************************************/

#include "ompt-specific.c"


/*****************************************************************************
 * macros
 ****************************************************************************/

#define ompt_get_callback_success 1
#define ompt_get_callback_failure 0

#define no_tool_present 0

#define OMPT_API_ROUTINE static

#ifndef OMPT_STR_MATCH
#define OMPT_STR_MATCH(haystack, needle) (!strcasecmp(haystack, needle))
#endif


/*****************************************************************************
 * types
 ****************************************************************************/

typedef struct {
    const char *state_name;
    ompt_state_t  state_id;
} ompt_state_info_t;


enum tool_setting_e {
    omp_tool_error,
    omp_tool_unset,
    omp_tool_disabled,
    omp_tool_enabled
};


typedef void (*ompt_initialize_t) (
    ompt_function_lookup_t ompt_fn_lookup, 
    const char *version,
    unsigned int ompt_version
);


/*****************************************************************************
 * global variables
 ****************************************************************************/

int ompt_enabled = 0;

ompt_state_info_t ompt_state_info[] = {
#define ompt_state_macro(state, code) { # state, state },
    FOREACH_OMPT_STATE(ompt_state_macro)
#undef ompt_state_macro
};

ompt_callbacks_t ompt_callbacks;

static ompt_initialize_t  ompt_initialize_fn = NULL;


/*****************************************************************************
 * forward declarations
 ****************************************************************************/

static ompt_interface_fn_t ompt_fn_lookup(const char *s);

OMPT_API_ROUTINE ompt_thread_id_t ompt_get_thread_id(void);


/*****************************************************************************
 * initialization and finalization (private operations)
 ****************************************************************************/

/* On Unix-like systems that support weak symbols the following implementation
 * of ompt_tool() will be used in case no tool-supplied implementation of
 * this function is present in the address space of a process.
 *
 * On Windows, the ompt_tool_windows function is used to find the
 * ompt_tool symbol across all modules loaded by a process. If ompt_tool is
 * found, ompt_tool's return value is used to initialize the tool. Otherwise,
 * NULL is returned and OMPT won't be enabled */
#if OMPT_HAVE_WEAK_ATTRIBUTE
_OMP_EXTERN 
__attribute__ (( weak ))
ompt_initialize_t ompt_tool()
{
#if OMPT_DEBUG
    printf("ompt_tool() is called from the RTL\n");
#endif
    return NULL;
}

#elif OMPT_HAVE_PSAPI

#include <psapi.h>
#pragma comment(lib, "psapi.lib")
#define ompt_tool ompt_tool_windows

// The number of loaded modules to start enumeration with EnumProcessModules()
#define NUM_MODULES 128

static
ompt_initialize_t ompt_tool_windows()
{
    int i;
    DWORD needed, new_size;
    HMODULE *modules;
    HANDLE  process = GetCurrentProcess();
    modules = (HMODULE*)malloc( NUM_MODULES * sizeof(HMODULE) );
    ompt_initialize_t (*ompt_tool_p)() = NULL;

#if OMPT_DEBUG
    printf("ompt_tool_windows(): looking for ompt_tool\n");
#endif
    if (!EnumProcessModules( process, modules, NUM_MODULES * sizeof(HMODULE),
                              &needed)) {
        // Regardless of the error reason use the stub initialization function
        free(modules);
        return NULL;
    }
    // Check if NUM_MODULES is enough to list all modules
    new_size = needed / sizeof(HMODULE);
    if (new_size > NUM_MODULES) {
#if OMPT_DEBUG
    printf("ompt_tool_windows(): resize buffer to %d bytes\n", needed);
#endif
        modules = (HMODULE*)realloc( modules, needed );
        // If resizing failed use the stub function.
        if (!EnumProcessModules(process, modules, needed, &needed)) {
            free(modules);
            return NULL;
        }
    }
    for (i = 0; i < new_size; ++i) {
        (FARPROC &)ompt_tool_p = GetProcAddress(modules[i], "ompt_tool");
        if (ompt_tool_p) {
#if OMPT_DEBUG
            TCHAR modName[MAX_PATH];
            if (GetModuleFileName(modules[i], modName, MAX_PATH))
                printf("ompt_tool_windows(): ompt_tool found in module %s\n",
                       modName);
#endif
            free(modules);
            return ompt_tool_p();
        }
#if OMPT_DEBUG
        else {
            TCHAR modName[MAX_PATH];
            if (GetModuleFileName(modules[i], modName, MAX_PATH))
                printf("ompt_tool_windows(): ompt_tool not found in module %s\n",
                       modName);
        }
#endif
    }
    free(modules);
    return NULL;
}
#else
# error Either __attribute__((weak)) or psapi.dll are required for OMPT support
#endif // OMPT_HAVE_WEAK_ATTRIBUTE

void ompt_pre_init()
{
    //--------------------------------------------------
    // Execute the pre-initialization logic only once.
    //--------------------------------------------------
    static int ompt_pre_initialized = 0;

    if (ompt_pre_initialized) return;

    ompt_pre_initialized = 1;

    //--------------------------------------------------
    // Use a tool iff a tool is enabled and available.
    //--------------------------------------------------
    const char *ompt_env_var = getenv("OMP_TOOL");
    tool_setting_e tool_setting = omp_tool_error;

    if (!ompt_env_var  || !strcmp(ompt_env_var, ""))
        tool_setting = omp_tool_unset;
    else if (OMPT_STR_MATCH(ompt_env_var, "disabled"))
        tool_setting = omp_tool_disabled;
    else if (OMPT_STR_MATCH(ompt_env_var, "enabled"))
        tool_setting = omp_tool_enabled;

#if OMPT_DEBUG
    printf("ompt_pre_init(): tool_setting = %d\n", tool_setting);
#endif
    switch(tool_setting) {
    case omp_tool_disabled:
        break;

    case omp_tool_unset:
    case omp_tool_enabled:
        ompt_initialize_fn = ompt_tool();
        if (ompt_initialize_fn) {
            ompt_enabled = 1;
        }
        break;

    case omp_tool_error:
        fprintf(stderr,
            "Warning: OMP_TOOL has invalid value \"%s\".\n"
            "  legal values are (NULL,\"\",\"disabled\","
            "\"enabled\").\n", ompt_env_var);
        break;
    }
#if OMPT_DEBUG
    printf("ompt_pre_init(): ompt_enabled = %d\n", ompt_enabled);
#endif
}


void ompt_post_init()
{
    //--------------------------------------------------
    // Execute the post-initialization logic only once.
    //--------------------------------------------------
    static int ompt_post_initialized = 0;

    if (ompt_post_initialized) return;

    ompt_post_initialized = 1;

    //--------------------------------------------------
    // Initialize the tool if so indicated.
    //--------------------------------------------------
    if (ompt_enabled) {
        ompt_initialize_fn(ompt_fn_lookup, ompt_get_runtime_version(), 
                           OMPT_VERSION);

        ompt_thread_t *root_thread = ompt_get_thread();

        ompt_set_thread_state(root_thread, ompt_state_overhead);

        if (ompt_callbacks.ompt_callback(ompt_event_thread_begin)) {
            ompt_callbacks.ompt_callback(ompt_event_thread_begin)
                (ompt_thread_initial, ompt_get_thread_id());
        }

        ompt_set_thread_state(root_thread, ompt_state_work_serial);
    }
}


void ompt_fini()
{
    if (ompt_enabled) {
        if (ompt_callbacks.ompt_callback(ompt_event_runtime_shutdown)) {
            ompt_callbacks.ompt_callback(ompt_event_runtime_shutdown)();
        }
    }

    ompt_enabled = 0;
}


/*****************************************************************************
 * interface operations
 ****************************************************************************/

/*****************************************************************************
 * state
 ****************************************************************************/

OMPT_API_ROUTINE int ompt_enumerate_state(int current_state, int *next_state,
                                          const char **next_state_name)
{
    const static int len = sizeof(ompt_state_info) / sizeof(ompt_state_info_t);
    int i = 0;

    for (i = 0; i < len - 1; i++) {
        if (ompt_state_info[i].state_id == current_state) {
            *next_state = ompt_state_info[i+1].state_id;
            *next_state_name = ompt_state_info[i+1].state_name;
            return 1;
        }
    }

    return 0;
}


/*****************************************************************************
 * callbacks
 ****************************************************************************/

OMPT_API_ROUTINE int ompt_set_callback(ompt_event_t evid, ompt_callback_t cb)
{
    switch (evid) {

#define ompt_event_macro(event_name, callback_type, event_id)                  \
    case event_name:                                                           \
        if (ompt_event_implementation_status(event_name)) {                    \
            ompt_callbacks.ompt_callback(event_name) = (callback_type) cb;     \
        }                                                                      \
        return ompt_event_implementation_status(event_name);

    FOREACH_OMPT_EVENT(ompt_event_macro)

#undef ompt_event_macro

    default: return ompt_set_result_registration_error;
    }
}


OMPT_API_ROUTINE int ompt_get_callback(ompt_event_t evid, ompt_callback_t *cb)
{
    switch (evid) {

#define ompt_event_macro(event_name, callback_type, event_id)                  \
    case event_name:                                                           \
        if (ompt_event_implementation_status(event_name)) {                    \
            ompt_callback_t mycb =                                             \
                (ompt_callback_t) ompt_callbacks.ompt_callback(event_name);    \
            if (mycb) {                                                        \
                *cb = mycb;                                                    \
                return ompt_get_callback_success;                              \
            }                                                                  \
        }                                                                      \
        return ompt_get_callback_failure;

    FOREACH_OMPT_EVENT(ompt_event_macro)

#undef ompt_event_macro

    default: return ompt_get_callback_failure;
    }
}


/*****************************************************************************
 * parallel regions
 ****************************************************************************/

OMPT_API_ROUTINE ompt_parallel_id_t ompt_get_parallel_id(int ancestor_level)
{
    return __ompt_get_parallel_id_internal(ancestor_level);
}


OMPT_API_ROUTINE int ompt_get_parallel_team_size(int ancestor_level)
{
    return __ompt_get_parallel_team_size_internal(ancestor_level);
}


OMPT_API_ROUTINE void *ompt_get_parallel_function(int ancestor_level)
{
    return __ompt_get_parallel_function_internal(ancestor_level);
}


OMPT_API_ROUTINE ompt_state_t ompt_get_state(ompt_wait_id_t *ompt_wait_id)
{
    ompt_state_t thread_state = __ompt_get_state_internal(ompt_wait_id);

    if (thread_state == ompt_state_undefined) {
        thread_state = ompt_state_work_serial;
    }

    return thread_state;
}


/*****************************************************************************
 * threads
 ****************************************************************************/


OMPT_API_ROUTINE void *ompt_get_idle_frame()
{
    return __ompt_get_idle_frame_internal();
}


/*****************************************************************************
 * tasks
 ****************************************************************************/


OMPT_API_ROUTINE ompt_thread_id_t ompt_get_thread_id(void)
{
    return __ompt_get_thread_id_internal();
}

OMPT_API_ROUTINE ompt_task_id_t ompt_get_task_id(int depth)
{
    return __ompt_get_task_id_internal(depth);
}


OMPT_API_ROUTINE ompt_frame_t *ompt_get_task_frame(int depth)
{
    return __ompt_get_task_frame_internal(depth);
}


OMPT_API_ROUTINE void *ompt_get_task_function(int depth)
{
    return __ompt_get_task_function_internal(depth);
}


/*****************************************************************************
 * placeholders
 ****************************************************************************/

// Don't define this as static. The loader may choose to eliminate the symbol
// even though it is needed by tools.  
#define OMPT_API_PLACEHOLDER 

// Ensure that placeholders don't have mangled names in the symbol table.
#ifdef __cplusplus
extern "C" {
#endif


OMPT_API_PLACEHOLDER void ompt_idle(void)  
{
    // This function is a placeholder used to represent the calling context of
    // idle OpenMP worker threads. It is not meant to be invoked.
    assert(0);
}


OMPT_API_PLACEHOLDER void ompt_overhead(void)
{
    // This function is a placeholder used to represent the OpenMP context of
    // threads working in the OpenMP runtime.  It is not meant to be invoked.
    assert(0);
}


OMPT_API_PLACEHOLDER void ompt_barrier_wait(void)
{
    // This function is a placeholder used to represent the OpenMP context of
    // threads waiting for a barrier in the OpenMP runtime. It is not meant
    // to be invoked.
    assert(0);
}


OMPT_API_PLACEHOLDER void ompt_task_wait(void)
{
    // This function is a placeholder used to represent the OpenMP context of
    // threads waiting for a task in the OpenMP runtime. It is not meant
    // to be invoked.
    assert(0);
}


OMPT_API_PLACEHOLDER void ompt_mutex_wait(void)
{
    // This function is a placeholder used to represent the OpenMP context of
    // threads waiting for a mutex in the OpenMP runtime. It is not meant
    // to be invoked.
    assert(0);
}

#ifdef __cplusplus
};
#endif


/*****************************************************************************
 * compatability
 ****************************************************************************/

OMPT_API_ROUTINE int ompt_get_ompt_version()
{
    return OMPT_VERSION;
}


/*****************************************************************************
 * application-facing API
 ****************************************************************************/


/*----------------------------------------------------------------------------
 | control
 ---------------------------------------------------------------------------*/

_OMP_EXTERN void ompt_control(uint64_t command, uint64_t modifier)
{
    if (ompt_enabled && ompt_callbacks.ompt_callback(ompt_event_control)) {
        ompt_callbacks.ompt_callback(ompt_event_control)(command, modifier);
    }
}


/*****************************************************************************
 * API inquiry for tool
 ****************************************************************************/

static ompt_interface_fn_t ompt_fn_lookup(const char *s)
{

#define ompt_interface_fn(fn) \
    if (strcmp(s, #fn) == 0) return (ompt_interface_fn_t) fn;

    FOREACH_OMPT_INQUIRY_FN(ompt_interface_fn)

    FOREACH_OMPT_PLACEHOLDER_FN(ompt_interface_fn)

    return (ompt_interface_fn_t) 0;
}