/*
 * backtrace.c
 *
 * Utilities related to backtrace
 *
 * Copyright (c) Citus Data, Inc.
 */

#include "postgres.h"
#include "backtrace.h"
#include "backtrace-supported.h"
#include "lib/stringinfo.h"

#include "distributed/backtrace.h"

#define BACKTRACE_HEADER "\nBACKTRACE:\n"
#define BACKTRACE_SKIP 2

static int BacktraceFullCallback(void *data, uintptr_t pc,
					const char *filename, int lineno,
					const char *function);

static void BacktraceErrorCallback(void *data, const char *msg, int errnum);
static void InitBackTrace(void);
static bool ShouldLogBacktrace(int elevel);
static char* GenerateBackTrace(void);

static struct backtrace_state* backTracestate;

static void InitBackTrace(void) {
    const char* filename = NULL;
    void* data = NULL;
	backTracestate = backtrace_create_state(filename, BACKTRACE_SUPPORTS_THREADS,
         BacktraceErrorCallback, data);
}

static bool ShouldLogBacktrace(int elevel) {
    return elevel >= ERROR;
}


void Backtrace(int elevel) {
    if (!ShouldLogBacktrace(elevel)) {
        return;
    }
    errdetail("%s", GenerateBackTrace());
 }

static char* GenerateBackTrace(void) {
    if (backTracestate == NULL) {
        InitBackTrace();
    }
    StringInfo msgWithBacktrace = makeStringInfo();

	appendStringInfoString(msgWithBacktrace, BACKTRACE_HEADER);
	backtrace_full(backTracestate, BACKTRACE_SKIP, BacktraceFullCallback,
        BacktraceErrorCallback, msgWithBacktrace);

    return msgWithBacktrace->data;
}

static int BacktraceFullCallback(void *data, uintptr_t pc, const char *filename, int lineno,
					const char *function) {
        
    StringInfo str = (StringInfo) data;
    if (function && filename) {
        appendStringInfo(str, "%s:%s:%d\n",filename, function, lineno);
    }
    /* returning 0 means we will continue the backtrace */
    return 0;
}

static void BacktraceErrorCallback(void *data, const char *msg, int errnum) {
    // currently NO-OP
}