// Tests for buffer performance.

#include "main.h"
#include <assert.h>
#include <iostream> 
#include <filesystem>
#include <limits.h>
#include <chrono>

#define BIN_SEARCH 0
#define BTREE_SEARCH 1

#define MEMTABLE_SIZE 1
#define MAX_EXPERIMENT_SIZE 1024
#define BUFFER_SIZE 10
#define BLOOMFILTER_BITS 5

double buffer_test(int buffer_size_mb) {
    std::cout << "Running exp_buffer, buffer size is: " << buffer_size_mb << " MB \n";

    std::filesystem::remove_all("db_t");

    int data_volume_mb = 128;
    int mem_size_mb = MEMTABLE_SIZE;
    int mem_size = (mem_size_mb * 1024 * 1024) / (2 * sizeof(int));
    int buffer_size = buffer_size_mb * 256; // assuming 4KB pages
    DB* db = Open("db_t", mem_size, buffer_size, buffer_size, BTREE_SEARCH, BLOOMFILTER_BITS);

    int num_kv = (data_volume_mb * 1024 * 1024) / (2 * sizeof(int));

    clock_t start, end;
    std::cout << "Populating the database...\n";
    for (int i = 0; i < num_kv; i++){
        db->put(i,-i);
    }
    std::cout << "Database populated, starting test...\n";

    int test_size = 128;
    int diff = num_kv / test_size;

    start = clock();
    auto real_start = std::chrono::high_resolution_clock::now();
    for (int j = 0; j < test_size; j++){
        for (int k = 0; k < 10; k++){
            db->get(j*diff+k);  // repeated gets within the same page
        }
    }
    for (int j = 0; j < test_size; j++){
        for (int k = 0; k < 10; k++){
            db->get(j*diff+k);  // repeated to further test buffer
        }
    }
    auto real_end = std::chrono::high_resolution_clock::now();
    end = clock();

    double test_size_mb = ((test_size*10*2)*sizeof(int)*2) / (1024.0 * 1024.0);
    double time_taken = double(end - start) / double(CLOCKS_PER_SEC);
    double real_time_taken = (std::chrono::duration_cast<std::chrono::microseconds>(real_end - real_start).count())/1000000.0;
    std::cout << "Buffer speed test finished. Time taken: " << real_time_taken << " seconds \n";
    std::cout << "Throughput: " << (test_size_mb / real_time_taken) << " MB/second \n";


    db->Close();

    // std::cout << "All tests ended\n\n";
    std::filesystem::remove_all("db_t");
    return real_time_taken;
}

int main(){
    std::cout << "Testing with buffer pool.";
    buffer_test(BUFFER_SIZE);
    std::cout << "Testing without buffer pool.";
    buffer_test(0);
    return 0;
}