/*
 * Created by Brett on 20/09/23.
 * Licensed under GNU General Public License V3.0
 * See LICENSE file for license detail
 */
#include <blt/profiling/profiler_v2.h>
#include <blt/std/time.h>
#include <blt/std/system.h>
#include <blt/std/format.h>
#include <functional>

namespace blt
{

#define SORT_INTERVALS_FUNC_MACRO(use_history, TYPE_END, TYPE_START, TYPE_TOTAL)                            \
    [&use_history](const interval_t* a, const interval_t* b) -> bool {                                      \
        if (use_history){                                                                                   \
            auto a_diff = a->TYPE_END - a->TYPE_START;                                                      \
            auto b_diff = b->TYPE_END - b->TYPE_START;                                                      \
            return a_diff > b_diff;                                                                         \
        } else {                                                                                            \
            return a->TYPE_TOTAL > b->TYPE_TOTAL;                                                           \
        }                                                                                                   \
    }

#define INTERVAL_DIFFERENCE_MACRO(printHistory, interval)                                                   \
    auto wall = printHistory                                                                                \
                ? (static_cast<double>(interval->wall_total) / static_cast<double>(interval->count))        \
                : static_cast<double>(interval->wall_end - interval->wall_start);                           \
                                                                                                            \
    auto thread = printHistory                                                                              \
                  ? (static_cast<double>(interval->thread_total) / static_cast<double>(interval->count))    \
                  : static_cast<double>(interval->thread_end - interval->thread_start);                     \
                                                                                                            \
    auto cycles = printHistory                                                                              \
                  ? (static_cast<double>(interval->cycles_total) / static_cast<double>(interval->count))    \
                  : static_cast<double>(interval->cycles_end - interval->cycles_start);
    
    enum class unit
    {
        MS, NS, S
    };
    
    struct unit_container
    {
        unit thread;
        unit wall;
    };
    
    interval_t* createInterval(profile_t& profiler, std::string interval_name)
    {
        auto interval = new interval_t(
                blt::system::getCurrentTimeNanoseconds(), 0, 0,
                blt::system::getCPUThreadTime(), 0, 0,
                blt::system::rdtsc(), 0, 0,
                0, std::move(interval_name));
        profiler.intervals.push_back(interval);
        return interval;
    }
    
    void startInterval(interval_t* interval)
    {
        interval->wall_start = blt::system::getCurrentTimeNanoseconds();
        interval->thread_start = blt::system::getCPUThreadTime();
        interval->cycles_start = blt::system::rdtsc();
    }
    
    void endInterval(interval_t* interval)
    {
        interval->cycles_end = blt::system::rdtsc();
        interval->wall_end = blt::system::getCurrentTimeNanoseconds();
        interval->thread_end = blt::system::getCPUThreadTime();
        
        interval->cycles_total += interval->cycles_end - interval->cycles_start;
        interval->wall_total += interval->wall_end - interval->wall_start;
        interval->thread_total += interval->thread_end - interval->thread_start;
        
        interval->count++;
    }
    
    void clearProfile(profile_t& profiler)
    {
        for (auto* p : profiler.intervals)
            delete p;
        for (auto* p : profiler.cycle_intervals)
            delete p;
        profiler.intervals.clear();
        profiler.cycle_intervals.clear();
    }
    
    void writeProfile(std::ifstream&, const profile_t&)
    {
        BLT_WARN("Write profile for V2 is currently a TODO");
    }
    
    void sort_intervals(std::vector<interval_t*>& intervals, sort_by sort, bool use_history)
    {
        std::function<bool(const interval_t* a, const interval_t* b)> sort_func;
        switch (sort)
        {
            case sort_by::CYCLES:
                BLT_DEBUG("Cycles");
                sort_func = SORT_INTERVALS_FUNC_MACRO(use_history, cycles_start, cycles_end, cycles_total);
                break;
            case sort_by::WALL:
                BLT_TRACE("WaLL");
                sort_func = SORT_INTERVALS_FUNC_MACRO(use_history, wall_start, wall_end, wall_total);
                break;
            case sort_by::THREAD:
                BLT_INFO("Thread!");
                sort_func = SORT_INTERVALS_FUNC_MACRO(use_history, thread_start, thread_end, thread_total);
                break;
        }
        std::sort(intervals.begin(), intervals.end(), sort_func);
    }
    
    unit_container determine_max_unit(const std::vector<interval_t*>& intervals, bool use_history)
    {
        // start at lowest unit
        unit_container container{unit::NS, unit::NS};
        // last one will always be the longest, at least according to the sort order
        // which should at least be close.
        auto interval = intervals[intervals.size() - 1];
        INTERVAL_DIFFERENCE_MACRO(use_history, interval);
        (void)(cycles);
        // make sure is in range + that we don't convert Seconds back to MS
        // we want to use the largest unit possible to keep the numbers small
        // we might run into a case where something took 1000ns but other thing took 100s
        // which would be hard to deal with either way. So TODO
        if (wall > 1e6 && wall < 1e9 && container.wall == unit::NS)
            container.wall = unit::MS;
        else if (wall > 1e9)
            container.wall = unit::S;
        
        if (thread > 1e6 && thread < 1e9 && container.thread == unit::NS)
            container.thread = unit::MS;
        else if (thread > 1e9)
            container.thread = unit::S;
        return container;
    }
    
    inline void println(const std::vector<std::string>&& lines, logging::log_level level) {
        for (const auto& line : lines)
            BLT_LOG_STREAM(level) << line << "\n";
    }
    
    void printProfile(profile_t& profiler, std::uint32_t flags, sort_by sort, blt::logging::log_level log_level)
    {
        bool printHistory = flags & PRINT_HISTORY;
        bool printCycles = flags & PRINT_CYCLES;
        bool printThread = flags & PRINT_THREAD;
        bool printWall = flags & PRINT_WALL;
        
        sort_intervals(profiler.intervals, sort, printHistory);
        
        auto units = determine_max_unit(profiler.intervals, printHistory);
        std::string thread_unit_string = units.thread == unit::MS ? "ms" : units.thread == unit::NS ? "ns" : "s";
        std::string wall_unit_string = units.wall == unit::MS ? "ms" : units.wall == unit::NS ? "ns" : "s";
        auto thread_unit_divide = units.thread == unit::MS ? 1e6 : units.thread == unit::NS ? 1 : 1e9;
        auto wall_unit_divide = units.wall == unit::MS ? 1e6 : units.wall == unit::NS ? 1 : 1e9;
        
        string::TableFormatter formatter{profiler.name};
        formatter.addColumn({"Order"});
        if (printHistory)
            formatter.addColumn({"Count"});
        formatter.addColumn({"Interval"});
        if (printCycles)
            formatter.addColumn({"Cycles"});
        if (printThread)
            formatter.addColumn({"CPU Time (" + thread_unit_string += ")"});
        if (printWall)
            formatter.addColumn({"Wall Time (" + wall_unit_string += ")"});
        
        for (size_t i = 0; i < profiler.intervals.size(); i++)
        {
            blt::string::TableRow row;
            auto interval = profiler.intervals[i];
            
            if (interval->count == 0)
                continue;
            
            INTERVAL_DIFFERENCE_MACRO(printHistory, interval);
            
            row.rowValues.push_back(std::to_string(i + 1));
            if (printHistory)
                row.rowValues.push_back(std::to_string(interval->count));
            row.rowValues.push_back(interval->interval_name);
            if (printCycles)
                row.rowValues.push_back(std::to_string(cycles));
            if (printThread)
                row.rowValues.push_back(std::to_string(thread / static_cast<double>(thread_unit_divide)));
            if (printWall)
                row.rowValues.push_back(std::to_string(wall / static_cast<double>(wall_unit_divide)));
            formatter.addRow(row);
        }
        
        println(formatter.createTable(true, true), log_level);
    }
    
    profile_t::~profile_t()
    {
        for (auto* p : intervals)
            delete p;
        for (auto* p : cycle_intervals)
            delete p;
    }
}