/*
 * Copyright (c) 2022-2023, NVIDIA CORPORATION.  All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#pragma once

#include <algorithm>   // min, max
#include <assert.h>    // assert
#include <float.h>     // FLT_MAX
#include <iostream>    // snprintf
#include <math.h>      // expf, log
#include <limits>      // numeric_limits
#include <stdlib.h>    // rand
#include <string>      // string
#include <vector>      // vector

#include "src/fastertransformer/utils/cuda_utils.h"
#include "src/fastertransformer/utils/memory_utils.h"
#include "src/fastertransformer/utils/string_utils.h"

#define PRINT_LIMIT 16
#define EPSILON (1e-20)
#define EPSILON_FP16 (1e-10)

using namespace fastertransformer;

class TestFailureError : public std::exception {
private:
    std::string msg_;
public:
    explicit TestFailureError() = default;
    explicit TestFailureError(std::string name, std::string msg = "") {
        msg_ = fmtstr("TEST FAIL [%s] %s", name.c_str(), msg.c_str());
    }
    const char* what () const throw () {
        return msg_.c_str();
    }
};

#define EXPECT_TRUE(cond)                                  \
    do { if(!(cond)) {                                     \
        FT_LOG_ERROR("TEST FAIL [%s]: %s at %s:%d",        \
                     __func__, #cond, __FILE__, __LINE__); \
        throw TestFailureError(__func__);                  \
    } } while(false)

#define EXPECT_FALSE(cond)                                 \
    do { if(cond) {                                        \
        FT_LOG_ERROR("TEST FAIL [%s]: %s at %s:%d",        \
                     __func__, #cond, __FILE__, __LINE__); \
        throw TestFailureError(__func__);                  \
    } } while(false)

bool almostEqual(float a, float b, float atol = 1e-5, float rtol = 1e-8)
{
    // Params: a = value to compare and b = reference
    // This function follows implementation of numpy.isclose(), which checks
    //   abs(a - b) <= (atol + rtol * abs(b)).
    // Note that the inequality above is asymmetric where b is considered as
    // a reference value. To account into both absolute/relative errors, it
    // uses absolute tolerance and relative tolerance at the same time. The
    // default values of atol and rtol borrowed from numpy.isclose(). For the
    // case of nan value, the result will be true.
    if (isnan(a) && isnan(b)) {
        return true;
    }
    return fabs(a - b) <= (atol + rtol * fabs(b));
}

template<typename T>
bool checkResult(std::string name, T* out, T*ref, size_t size, float atol, float rtol) {
    size_t failures = 0;
    float relative_gap = 0.0f;;

    for (size_t i = 0; i < size; ++i) {
        // The values for the output and the reference.
        float a = (float)out[i];
        float b = (float)ref[i];

        bool ok = almostEqual(a, b, atol, rtol);
        // Print the error.
        if (!ok && failures < 4) {
            FT_LOG_ERROR(">> invalid result for i=%lu:", i);
            FT_LOG_ERROR(">>    found......: %10.6f", a);
            FT_LOG_ERROR(">>    expected...: %10.6f", b);
            FT_LOG_ERROR(">>    error......: %.6f", fabsf(a - b));
            FT_LOG_ERROR(">>    tol........: %.6f", atol + rtol * fabs(b));
        }
        // Update the number of failures.
        failures += ok ? 0 : 1;
        // Update the relative gap.
        relative_gap += fabsf(a - b) / (fabsf(b) + EPSILON);
    }

    relative_gap /= size;

    // Allow not matched up to 1% elements.
    size_t tol_failures = (size_t)(0.01 * size);
    FT_LOG_INFO("check...%6s : %-50s (failures: %.2f%% atol: %.2e rtol: %.2e rel_gap: %.2e%%)",
                failures <= tol_failures ? "....OK" : "FAILED", name.c_str(),
                100. * failures / size, atol, rtol, 100. * relative_gap);
    return failures <= tol_failures;
}

template<typename T>
bool checkResult(std::string name, T* out, T* ref, size_t size,
                 bool device_out = true, bool device_ref = false)
{
    bool is_fp32 = sizeof(T) == 4;
    float atol = is_fp32 ? 1e-4f : 1e-3f;
    float rtol = is_fp32 ? 1e-2f : 1e-1f;

    T* h_out = nullptr;
    if (device_out) {
        h_out = new T[size];
        cudaMemcpy(h_out, out, sizeof(T) * size, cudaMemcpyDeviceToHost);
        out = h_out;
    }
    T* h_ref = nullptr;
    if (device_ref) {
        h_ref = new T[size];
        cudaMemcpy(h_ref, ref, sizeof(T) * size, cudaMemcpyDeviceToHost);
        ref = h_ref;
    }
    bool is_ok = checkResult(name, out, ref, size, atol, rtol);
    if (h_out != nullptr){
        delete[] h_out;
    }
    if (h_ref != nullptr) {
        delete[] h_ref;
    }
    return is_ok;
}

template<typename T>
void initRandom(T* ptr, size_t size, float minval, float maxval) {
    for (size_t i = 0; i < size; ++i) {
        float val = static_cast<float>(rand()) / static_cast<float>(RAND_MAX);
        val *= (maxval - minval);
        ptr[i] = static_cast<T>(minval + val);
    }
}

void initRandomInt(int* ptr, size_t size, int minval, int maxval) {
    assert(minval < maxval);
    int mod = maxval - minval;
    for (size_t i = 0; i < size; ++i) {
        ptr[i] = minval + rand() % mod;
    }
}

template<typename T>
void tile(T* x, int m, int n) {
    for (int i = 1; i < m; ++i) {
        for (int j = 0; j < n; ++j) {
            x[i * n + j] = x[j];
        }
    }
}

template<typename T>
void tile(T* dst, T* src, int m, int n) {
    for (int i = 1; i < m; ++i) {
        for (int j = 0; j < n; ++j) {
            dst[i * n + j] = src[j];
        }
    }
}

#define HALF_FLT_MAX 65504.0f

template<typename T>
bool isHalf() {
    return std::is_same<T, half>::value;
}

template<typename T>
static inline void printMatrixWithLimit(T* ptr, int m, int k, int stride, bool is_device_ptr) {
    printMatrix(ptr, std::min(PRINT_LIMIT, m), std::min(PRINT_LIMIT, k), stride, is_device_ptr);
}
