// Copyright 2009 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

#include <algorithm>
#include <chrono>
#include <map>
#include <mutex>
#include <string>

#include <fmt/format.h>
#include <imgui.h>
#ifndef IMGUI_DEFINE_MATH_OPERATORS
#define IMGUI_DEFINE_MATH_OPERATORS
#endif
#include <imgui_internal.h>

#include "Common/CommonTypes.h"
#include "Common/Logging/Log.h"
#include "Common/Timer.h"
#include "Core/Core.h"
#include "Core/ConfigManager.h"
#include "Core/Slippi/SlippiPlayback.h"
#include "VideoCommon/OnScreenDisplay.h"
#include "VideoCommon/IconsFontAwesome4.h"

extern std::unique_ptr<SlippiPlaybackStatus> g_playbackStatus;

namespace OSD
{
constexpr float LEFT_MARGIN = 10.0f;    // Pixels to the left of OSD messages.
constexpr float TOP_MARGIN = 10.0f;     // Pixels above the first OSD message.
constexpr float WINDOW_PADDING = 4.0f;  // Pixels between subsequent OSD messages.

struct Message
{
  Message() = default;
  Message(std::string text_, u32 timestamp_, u32 color_)
      : text(std::move(text_)), timestamp(timestamp_), color(color_)
  {
  }
  std::string text;
  u32 timestamp = 0;
  u32 color = 0;
};
static std::multimap<MessageType, Message> s_messages;
static std::mutex s_messages_mutex;
static int frame = 0;

u32 idle_tick = Common::Timer::GetTimeMs();
ImVec2 prev_mouse(0,0);

static ImVec4 RGBAToImVec4(const u32 rgba)
{
  return ImVec4(static_cast<float>((rgba >> 16) & 0xFF) / 255.0f,
                static_cast<float>((rgba >> 8) & 0xFF) / 255.0f,
                static_cast<float>((rgba >> 0) & 0xFF) / 255.0f,
                static_cast<float>((rgba >> 24) & 0xFF) / 255.0f);
}

static float DrawMessage(int index, const Message& msg, const ImVec2& position, int time_left)
{
  // We have to provide a window name, and these shouldn't be duplicated.
  // So instead, we generate a name based on the number of messages drawn.
  const std::string window_name = fmt::format("osd_{}", index);

  // The size must be reset, otherwise the length of old messages could influence new ones.
  ImGui::SetNextWindowPos(position);
  ImGui::SetNextWindowSize(ImVec2(0.0f, 0.0f));

  // Gradually fade old messages away.
  const float alpha = std::min(1.0f, std::max(0.0f, time_left / 1024.0f));
  ImGui::PushStyleVar(ImGuiStyleVar_Alpha, alpha);

  float window_height = 0.0f;
  if (ImGui::Begin(window_name.c_str(), nullptr,
                   ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoInputs |
                       ImGuiWindowFlags_NoMove | ImGuiWindowFlags_NoSavedSettings |
                       ImGuiWindowFlags_NoScrollbar | ImGuiWindowFlags_NoNav |
                       ImGuiWindowFlags_AlwaysAutoResize | ImGuiWindowFlags_NoFocusOnAppearing))
  {
    // Use %s in case message contains %.
    ImGui::TextColored(RGBAToImVec4(msg.color), "%s", msg.text.c_str());
    window_height =
        ImGui::GetWindowSize().y + (WINDOW_PADDING * ImGui::GetIO().DisplayFramebufferScale.y);
  }

  ImGui::End();
  ImGui::PopStyleVar();

  return window_height;
}

void AddTypedMessage(MessageType type, std::string message, u32 ms, u32 rgba)
{
  std::lock_guard lock{s_messages_mutex};
  s_messages.erase(type);
  s_messages.emplace(type, Message(std::move(message), Common::Timer::GetTimeMs() + ms, rgba));
}

void AddMessage(std::string message, u32 ms, u32 rgba)
{
  std::lock_guard lock{s_messages_mutex};
  s_messages.emplace(MessageType::Typeless,
                     Message(std::move(message), Common::Timer::GetTimeMs() + ms, rgba));
}

void DrawMessages()
{
  const bool draw_messages = SConfig::GetInstance().bOnScreenDisplayMessages;
  const u32 now = Common::Timer::GetTimeMs();
  const float current_x = LEFT_MARGIN * ImGui::GetIO().DisplayFramebufferScale.x;
  float current_y = TOP_MARGIN * ImGui::GetIO().DisplayFramebufferScale.y;
  int index = 0;

  std::lock_guard lock{s_messages_mutex};

  for (auto it = s_messages.begin(); it != s_messages.end();)
  {
    const Message& msg = it->second;
    const int time_left = static_cast<int>(msg.timestamp - now);

    if (time_left <= 0)
    {
      it = s_messages.erase(it);
      continue;
    }
    else
    {
      ++it;
    }

    if (draw_messages)
      current_y += DrawMessage(index++, msg, ImVec2(current_x, current_y), time_left);
  }
}

void ClearMessages()
{
  std::lock_guard lock{s_messages_mutex};
  s_messages.clear();
}

bool ButtonCustom(const char* label, const ImVec2& size_arg, ImGuiButtonFlags flags = 0)
{
  ImGuiWindow* window = ImGui::GetCurrentWindow();
  if (window->SkipItems)
    return false;

  ImGuiContext& g = *GImGui;
  const ImGuiStyle& style = g.Style;
  const ImGuiID id = window->GetID(label);
  const ImVec2 label_size = ImGui::CalcTextSize(label, NULL, true);

  ImVec2 pos = window->DC.CursorPos;
  if ((flags & ImGuiButtonFlags_AlignTextBaseLine) && style.FramePadding.y < window->DC.CurrentLineTextBaseOffset) // Try to vertically align buttons that are smaller/have no padding so that text baseline matches (bit hacky, since it shouldn't be a flag)
    pos.y += window->DC.CurrentLineTextBaseOffset - style.FramePadding.y;
  ImVec2 size = ImGui::CalcItemSize(size_arg, label_size.x + style.FramePadding.x * 2.0f, label_size.y + style.FramePadding.y * 2.0f);

  const ImRect bb(pos, pos + size);
  ImGui::ItemSize(size, style.FramePadding.y);
  if (!ImGui::ItemAdd(bb, id))
    return false;

  if (window->DC.ItemFlags & ImGuiItemFlags_ButtonRepeat)
    flags |= ImGuiButtonFlags_Repeat;
  bool hovered, held;
  bool pressed = ImGui::ButtonBehavior(bb, id, &hovered, &held, flags);
  if (pressed)
    ImGui::MarkItemEdited(id);

  // Render
  const ImU32 col = ImGui::GetColorU32(ImVec4(0.0f, 0.0f, 0.0f, 0.0f));
  ImGui::RenderNavHighlight(bb, id);
  ImGui::RenderFrame(bb.Min, bb.Max, col, true, style.FrameRounding);

  if (hovered || held)
    ImGui::RenderTextClipped(bb.Min + style.FramePadding, bb.Max - style.FramePadding, label, NULL, &label_size, style.ButtonTextAlign, &bb, ImVec4(0.9f, 0.9f, 0.9f, style.Alpha));
  else
    ImGui::RenderTextClipped(bb.Min + style.FramePadding, bb.Max - style.FramePadding, label, NULL, &label_size, style.ButtonTextAlign, &bb, ImVec4(0.9f, 0.9f, 0.9f, 0.6f * style.Alpha));

  // Automatically close popups
  //if (pressed && !(flags & ImGuiButtonFlags_DontClosePopups) && (window->Flags & ImGuiWindowFlags_Popup))
  //    CloseCurrentPopup();

  IMGUI_TEST_ENGINE_ITEM_INFO(id, label, window->DC.LastItemStatusFlags);
  return pressed;
}

bool SliderCustomBehavior(const ImRect& bb, ImGuiID id, int* v, int v_min, int v_max, float power, ImGuiSliderFlags flags, ImVec4 color, ImVec2 valuesize, const char* label, char* value)
{
  ImGuiContext& g = *GImGui;
  const ImGuiStyle& style = g.Style;
  ImGuiWindow* window = ImGui::GetCurrentWindow();
  const ImGuiAxis axis = (flags & ImGuiSliderFlags_Vertical) ? ImGuiAxis_Y : ImGuiAxis_X;
  const bool is_decimal = false; // TODO handle other types
  const bool is_power = (power != 1.0f) && is_decimal;

  const float slider_sz = (bb.Max[axis] - bb.Min[axis]);
  const float slider_usable_pos_min = bb.Min[axis];
  const float slider_usable_pos_max = bb.Max[axis];

  float linear_zero_pos = 0.0f;
  if (is_power && v_min * v_max < 0.0f)
  {
    const float linear_dist_min_to_0 = ImPow(v_min >= 0 ? (float)v_min : -(float)v_min, (float)1.0f / power);
    const float linear_dist_max_to_0 = ImPow(v_max >= 0 ? (float)v_max : -(float)v_max, (float)1.0f / power);
    linear_zero_pos = (float)(linear_dist_min_to_0 / (linear_dist_min_to_0 + linear_dist_max_to_0));
  }
  else
  {
    linear_zero_pos = v_min < 0.0f ? 1.0f : 0.0f;
  }

  const bool isDown = g.IO.MouseDown[0];
  bool value_changed = false;
  bool isActive = g.ActiveId == id;
  static bool isHeld = false;
  const bool hovered = ImGui::ItemHoverable(bb, id);
  if (isHeld) {
    isHeld = isHeld && isDown;
    // If no longer held, slider was let go. Trigger mark edited
    if (!isHeld) {
      INFO_LOG(SLIPPI, "Do seek here!");
      ImGui::MarkItemEdited(id); // TODO only mark on mouse up
    }
  }
  else
    isHeld = hovered && isDown;

  if (!isDown && isActive)
    ImGui::ClearActiveID();

  // Calculate mouse position if hovered
  int new_value = 0;
  if (hovered || isHeld) {
    const float mouse_abs_pos = g.IO.MousePos[axis];
    float clicked_t = (slider_sz > 0.0f) ? ImClamp((mouse_abs_pos - slider_usable_pos_min) / slider_sz, 0.0f, 1.0f) : 0.0f;
    if (axis == ImGuiAxis_Y)
      clicked_t = 1.0f - clicked_t;


    if (is_power)
    {
      if (clicked_t < linear_zero_pos)
      {
        float a = 1.0f - (clicked_t / linear_zero_pos);
        a = ImPow(a, power);
        new_value = ImLerp(ImMin(v_max, 0), v_min, a);
      }
      else
      {
        float a;
        if (ImFabs(linear_zero_pos - 1.0f) > 1.e-6f)
          a = (clicked_t - linear_zero_pos) / (1.0f - linear_zero_pos);
        else
          a = clicked_t;
        a = ImPow(a, power);
        new_value = ImLerp(ImMax(v_min, 0), v_max, a);
      }
    }
    else
    {
      new_value = ImLerp(v_min, v_max, clicked_t);
    }

    // Only change value if left mouse button is actually down
    if (*v != new_value && isDown)
    {
      *v = new_value;
      value_changed = true;
    }
  }

  float new_grab_t = ImGui::SliderCalcRatioFromValueT<int, float>(ImGuiDataType_S32, new_value, v_min, v_max, power, linear_zero_pos);
  float curr_grab_t = ImGui::SliderCalcRatioFromValueT<int, float>(ImGuiDataType_S32, *v, v_min, v_max, power, linear_zero_pos);

  if (axis == ImGuiAxis_Y) {
    new_grab_t = 1.0f - new_grab_t;
    curr_grab_t = 1.0f - curr_grab_t;
  }
  const float new_grab_pos = ImLerp(slider_usable_pos_min, slider_usable_pos_max, new_grab_t);
  const float curr_grab_pos = ImLerp(slider_usable_pos_min, slider_usable_pos_max, curr_grab_t);
  ImRect new_grab_bb;
  ImRect curr_grab_bb;
  if (axis == ImGuiAxis_X) {
    new_grab_bb = ImRect(ImVec2(new_grab_pos, bb.Min.y), ImVec2(new_grab_pos, bb.Max.y));
    curr_grab_bb = ImRect(ImVec2(curr_grab_pos, bb.Min.y), ImVec2(curr_grab_pos, bb.Max.y));
  }
  else
  {
    new_grab_bb = ImRect(ImVec2(bb.Min.x, new_grab_pos), ImVec2(bb.Max.x, new_grab_pos));
    curr_grab_bb = ImRect(ImVec2(bb.Min.x, curr_grab_pos), ImVec2(bb.Max.x, curr_grab_pos));
  }

  // Draw all the things

  // Darken screen when seeking
  if (isHeld)
    window->DrawList->AddRectFilled(ImVec2(0, 0), ImGui::GetIO().DisplaySize, ImGui::ColorConvertFloat4ToU32(ImVec4(0.0f, 0.0f, 0.0f, 0.5f)));

  window->DrawList->AddRectFilled(ImVec2(0, ImGui::GetWindowHeight() - 36), ImVec2(ImGui::GetWindowWidth(), ImGui::GetWindowHeight()), ImGui::ColorConvertFloat4ToU32(ImVec4(0.0f, 0.0f, 0.0f, 0.75f * style.Alpha)));

  // Grey background line
  window->DrawList->AddLine(ImVec2(bb.Min.x, bb.Max.y - 6), ImVec2(bb.Max.x, bb.Max.y - 6), ImGui::ColorConvertFloat4ToU32(ImVec4(1.0f, 1.0f, 1.0f, 0.5f * style.Alpha)), 4);

  // Whiter, more opaque line up to mouse position
  if (hovered && !isDown)
    window->DrawList->AddLine(ImVec2(bb.Min.x, bb.Max.y - 6), ImVec2(new_grab_bb.Min.x, bb.Max.y - 6), ImGui::ColorConvertFloat4ToU32(ImVec4(1.0f, 1.0f, 1.0f, style.Alpha)), 4);

  // Colored line, circle indicator, and text
  if (isHeld) {
    window->DrawList->AddLine(ImVec2(bb.Min.x, bb.Max.y - 6), ImVec2(new_grab_bb.Min.x, bb.Max.y - 6), ImGui::ColorConvertFloat4ToU32(ImVec4(0.0f, 1.0f, 0.0f, style.Alpha)), 4);
    window->DrawList->AddCircleFilled(ImVec2(new_grab_bb.Min.x, new_grab_bb.Max.y - 6), 6, ImGui::ColorConvertFloat4ToU32(ImVec4(0.0f, 1.0f, 0.0f, style.Alpha)));
    window->DrawList->AddText(ImVec2(new_grab_bb.GetCenter().x - valuesize.x / 2, bb.Max.y - 30), ImColor(255, 255, 255), value, label);
  }

  // Progress bar
  if (!isHeld)
    frame = g_playbackStatus->currentPlaybackFrame;
    window->DrawList->AddLine(ImVec2(bb.Min.x, bb.Max.y - 6), ImVec2(curr_grab_bb.Min.x, bb.Max.y - 6), ImGui::ColorConvertFloat4ToU32(ImVec4(0.0f, 1.0f, 0.0f, style.Alpha)), 4);

  return value_changed;
}

bool SliderCustom(const char* label, ImVec4 color, int* v, int v_min, int v_max, float power, const char* format)
{
  ImGuiWindow* window = ImGui::GetCurrentWindow();
  if (window->SkipItems)
    return false;

  ImGuiContext& g = *GImGui;
  const ImGuiStyle& style = g.Style;
  const ImGuiID id = window->GetID(label);
  const float w = ImGui::CalcItemWidth();

  const ImVec2 label_size = ImGui::CalcTextSize(label, NULL, true) * 1.0f;
  const ImRect frame_bb(window->DC.CursorPos, window->DC.CursorPos + ImVec2(w, label_size.y));

  const bool hovered = ImGui::ItemHoverable(frame_bb, id);
  if (hovered)
    ImGui::SetHoveredID(id);

  if (!format)
    format = "%d";

  bool start_text_input = false;
  const bool tab_focus_requested = ImGui::FocusableItemRegister(window, g.ActiveId == id);
  if (tab_focus_requested || (hovered && g.IO.MouseClicked[0]))
  {
    ImGui::SetActiveID(id, window);
    ImGui::FocusWindow(window);

    if (tab_focus_requested || g.IO.KeyCtrl)
    {
      start_text_input = true;
      g.ScalarAsInputTextId = 0;
    }
  }
  if (start_text_input || (g.ActiveId == id && g.ScalarAsInputTextId == id))
    return ImGui::InputScalarAsWidgetReplacement(frame_bb, id, label, ImGuiDataType_S32, v, format);

  char value_buf[64];
  const char* value_buf_end = value_buf + ImFormatString(value_buf, IM_ARRAYSIZE(value_buf), format, *v);
  const bool value_changed = SliderCustomBehavior(frame_bb, id, v, v_min, v_max, power, ImGuiSliderFlags_None, color, ImGui::CalcTextSize(value_buf, NULL, true), value_buf_end, value_buf);

  if (label_size.x > 0.0f)
    ImGui::RenderText(ImVec2(frame_bb.Min.x + style.ItemInnerSpacing.x, frame_bb.Min.y + 25), label);

  return value_changed;
}

void DrawSlippiPlaybackControls()
{
  const auto height = ImGui::GetWindowHeight();
  // We have to provide a window name, and these shouldn't be duplicated.
  // So instead, we generate a name based on the number of messages drawn.
  const std::string window_name = fmt::format("Slippi Playback Controls");
  ImGui::SetNextWindowPos(ImVec2(0, 0));
  ImGui::SetNextWindowSize(ImGui::GetIO().DisplaySize);

  auto mousePos = ImGui::GetMousePos();

  auto currTime = Common::Timer::GetTimeMs();
  if (!(mousePos[0] == prev_mouse[0] && mousePos[1] == prev_mouse[1])) {
    idle_tick = currTime;
  }
  prev_mouse = mousePos;

  s32 diff = currTime - idle_tick;
  diff = diff < 1000 ? 0 : diff - 1000;
  auto alpha = std::max(0.0001f, 1.0f - (diff / 1000.0f));

  ImGuiStyle& style = ImGui::GetStyle();
  style.WindowBorderSize = 0.0f;
  style.Alpha = alpha;
  style.WindowPadding = ImVec2(0.0f, 0.0f);

  if (ImGui::Begin(window_name.c_str(), nullptr,
    ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoMove | ImGuiWindowFlags_NoSavedSettings |
    ImGuiWindowFlags_NoScrollbar | ImGuiWindowFlags_NoNav | ImGuiWindowFlags_NoBackground |
    ImGuiWindowFlags_AlwaysAutoResize | ImGuiWindowFlags_NoFocusOnAppearing))
  {
    ImGui::PushItemWidth(ImGui::GetWindowWidth());
    ImGui::SetCursorPos(ImVec2(0.0f, ImGui::GetWindowHeight() - 44));
    SliderCustom("", ImVec4(1.0f, 0.0f, 0.0f, 1.0f), &frame, 0, 8000, 1.0, "%d");
    ImGui::SetCursorPos(ImVec2(0.0f, ImGui::GetWindowHeight() - 30));
    ImGui::PushStyleVar(ImGuiStyleVar_ButtonTextAlign, ImVec2(1.0f, 0.5f));
    if (ButtonCustom(ICON_FA_PLAY, ImVec2(32.0f, 32.0f))) {
      INFO_LOG(SLIPPI, "playing");
    }
    ImGui::PopStyleVar();
    ImGui::SameLine(0.0f);
    if (ButtonCustom(ICON_FA_FAST_BACKWARD, ImVec2(32.0f, 32.0f))) {
      INFO_LOG(SLIPPI, "fast back");
    }
    ImGui::SameLine(0.0f, 0.0f);
    if (ButtonCustom(ICON_FA_STEP_BACKWARD, ImVec2(32.0f, 32.0f))) {
      INFO_LOG(SLIPPI, "step back");
    }
    ImGui::SameLine(0.0f, 0.0f);
    if (ButtonCustom(ICON_FA_STEP_FORWARD, ImVec2(32.0f, 32.0f))) {
      INFO_LOG(SLIPPI, "step forward");
    }
    ImGui::SameLine(0.0f, 0.0f);
    if (ButtonCustom(ICON_FA_FAST_FORWARD, ImVec2(32.0f, 32.0f))) {
      INFO_LOG(SLIPPI, "fast_foward");
    }
  }
  ImGui::End();
}
}  // namespace OSD