#include "character/CharacterActionLibrary.h"
#include <SDL2/SDL.h>
#include <frostbite2D/resource/pvf_archive.h>
#include <frostbite2D/resource/script_parser.h>
#include <algorithm>
#include <cctype>
#include <sstream>
#include <vector>

namespace frostbite2D {
namespace {

std::string toLower(const std::string& value) {
  std::string result = value;
  std::transform(result.begin(), result.end(), result.begin(),
                 [](unsigned char c) { return static_cast<char>(std::tolower(c)); });
  return result;
}

int toInt(const std::string& value, int fallback = 0) {
  try {
    return std::stoi(value);
  } catch (...) {
    return fallback;
  }
}

float toFloat(const std::string& value, float fallback = 0.0f) {
  try {
    return std::stof(value);
  } catch (...) {
    return fallback;
  }
}

bool isTrueToken(const std::string& value) {
  std::string token = toLower(value);
  return token == "1" || token == "true" || token == "[true]" || token == "yes";
}

std::string trim(const std::string& value) {
  size_t begin = 0;
  size_t end = value.size();
  while (begin < end && std::isspace(static_cast<unsigned char>(value[begin]))) {
    ++begin;
  }
  while (end > begin
      && std::isspace(static_cast<unsigned char>(value[end - 1]))) {
    --end;
  }
  return value.substr(begin, end - begin);
}

std::string fileStem(const std::string& path) {
  size_t slashPos = path.find_last_of("/\\");
  size_t begin = slashPos == std::string::npos ? 0 : slashPos + 1;
  size_t dotPos = path.find_last_of('.');
  if (dotPos == std::string::npos || dotPos < begin) {
    return path.substr(begin);
  }
  return path.substr(begin, dotPos - begin);
}

class ScriptTokenStream {
public:
  explicit ScriptTokenStream(const std::string& path)
      : path_(PvfArchive::get().normalizePath(path)) {
    auto rawData = PvfArchive::get().getFileRawData(path_);
    if (!rawData) {
      return;
    }

    ScriptParser parser(*rawData, path_);
    if (!parser.isValid()) {
      return;
    }

    for (const auto& value : parser.parseAll()) {
      tokens_.push_back(value.toString());
    }
    valid_ = true;
  }

  bool IsValid() const { return valid_; }
  bool IsEnd() const { return index_ >= tokens_.size(); }

  std::string Next() {
    if (IsEnd()) {
      return {};
    }
    return tokens_[index_++];
  }

private:
  std::string path_;
  std::vector<std::string> tokens_;
  size_t index_ = 0;
  bool valid_ = false;
};

// action_list.lst 同时兼容两种格式：
// 1. 标准 PVF #PVF_File + 索引 + `path`
// 2. 早期临时版的 actionId + path 成对写法
bool isNewActionListPath(const std::string& path) {
  return path.find("action_logic") != std::string::npos
      && path.size() >= 4
      && path.substr(path.size() - 4) == ".act";
}

// action_list.lst only accepts #PVF_File entries like `swordman/action_logic/idle.act`.
std::vector<std::pair<std::string, std::string>> parseActionListEntries(
    ScriptTokenStream& listStream) {
  std::vector<std::pair<std::string, std::string>> entries;
  std::vector<std::string> tokens;
  auto& pvf = PvfArchive::get();
  while (!listStream.IsEnd()) {
    std::string token = trim(listStream.Next());
    if (!token.empty()) {
      tokens.push_back(token);
    }
  }

  for (size_t i = 0; i + 1 < tokens.size(); i += 2) {
    std::string rawActionPath = trim(tokens[i + 1]);
    std::string actionPath = pvf.normalizePath(rawActionPath);
    if (actionPath.empty() || !isNewActionListPath(actionPath)) {
      continue;
    }
    entries.push_back({toLower(fileStem(actionPath)), actionPath});
  }
  return entries;
}

CharacterFrameEventType parseFrameEventType(const std::string& token) {
  std::string lower = toLower(token);
  if (lower == "open_hit_window") {
    return CharacterFrameEventType::OpenHitWindow;
  }
  if (lower == "close_hit_window") {
    return CharacterFrameEventType::CloseHitWindow;
  }
  if (lower == "open_input_buffer") {
    return CharacterFrameEventType::OpenInputBuffer;
  }
  if (lower == "close_input_buffer") {
    return CharacterFrameEventType::CloseInputBuffer;
  }
  if (lower == "set_velocity_xy") {
    return CharacterFrameEventType::SetVelocityXY;
  }
  if (lower == "set_velocity_z") {
    return CharacterFrameEventType::SetVelocityZ;
  }
  if (lower == "finish_action") {
    return CharacterFrameEventType::FinishAction;
  }
  return CharacterFrameEventType::AnimationEvent;
}

void addOrReplaceAction(std::map<std::string, CharacterActionDefinition>& actions,
                        CharacterActionDefinition definition) {
  if (definition.actionId.empty()) {
    return;
  }
  actions[definition.actionId] = std::move(definition);
}

} // namespace

void CharacterCommandBuffer::Advance(float deltaTime) {
  for (auto& button : buttons_) {
    button.age += deltaTime;
  }
  buttons_.erase(
      std::remove_if(buttons_.begin(), buttons_.end(),
                     [this](const BufferedButton& button) {
                       return button.age > bufferWindowSeconds_;
                     }),
      buttons_.end());
}

void CharacterCommandBuffer::Submit(const CharacterCommand& command) {
  if (command.type == CharacterCommandType::Move) {
    moveAxis_ = command.moveAxis;
    if (moveAxis_.lengthSquared() > 1.0f) {
      moveAxis_ = moveAxis_.normalized();
    }
    return;
  }

  buttons_.push_back({command.type, 0.0f});
}

CharacterIntent CharacterCommandBuffer::BuildIntent() const {
  CharacterIntent intent;
  intent.moveX = moveAxis_.x;
  intent.moveY = moveAxis_.y;
  intent.wantJump = HasBuffered(CharacterCommandType::JumpPressed);
  intent.wantAttack = HasBuffered(CharacterCommandType::AttackPressed);
  intent.wantSkill1 = HasBuffered(CharacterCommandType::Skill1Pressed);
  intent.wantDash = HasBuffered(CharacterCommandType::DashPressed);
  return intent;
}

bool CharacterCommandBuffer::HasBuffered(CharacterCommandType type) const {
  for (const auto& button : buttons_) {
    if (button.type == type) {
      return true;
    }
  }
  return false;
}

void CharacterCommandBuffer::Consume(CharacterCommandType type) {
  auto it = std::find_if(buttons_.begin(), buttons_.end(),
                         [type](const BufferedButton& button) {
                           return button.type == type;
                         });
  if (it != buttons_.end()) {
    buttons_.erase(it);
  }
}

void CharacterCommandBuffer::Clear() {
  moveAxis_ = Vec2::Zero();
  buttons_.clear();
}

bool CharacterActionLibrary::LoadForConfig(const character::CharacterConfig& config) {
  actions_.clear();
  TryLoadPvfActionScripts(config);
  return !actions_.empty();
}

const CharacterActionDefinition* CharacterActionLibrary::FindAction(
    const std::string& actionId) const {
  auto it = actions_.find(actionId);
  if (it != actions_.end()) {
    return &it->second;
  }
  return nullptr;
}

const CharacterActionDefinition* CharacterActionLibrary::GetDefaultAction() const {
  return FindAction("idle");
}

std::string CharacterActionLibrary::DescribeActionIds() const {
  if (actions_.empty()) {
    return "<none>";
  }

  std::ostringstream stream;
  bool first = true;
  for (const auto& [actionId, definition] : actions_) {
    (void)definition;
    if (!first) {
      stream << ", ";
    }
    stream << actionId;
    first = false;
  }
  return stream.str();
}

bool CharacterActionLibrary::TryLoadPvfActionScripts(
    const character::CharacterConfig& config) {
  std::string listPath = "character/" + config.jobTag + "/action_logic/action_list.lst";
  ScriptTokenStream listStream(listPath);
  if (!listStream.IsValid()) {
    return false;
  }

  auto entries = parseActionListEntries(listStream);
  if (entries.empty()) {
    SDL_LogWarn(SDL_LOG_CATEGORY_APPLICATION,
                "CharacterActionLibrary: action_list parsed 0 entries from %s",
                listPath.c_str());
  }
  for (const auto& [actionId, relativePath] : entries) {
    if (actionId.empty() || relativePath.empty()) {
      continue;
    }

    std::string fullActPath = relativePath.rfind("character/", 0) == 0
                                ? relativePath
                                : "character/" + relativePath;
    ScriptTokenStream actionStream(fullActPath);
    if (!actionStream.IsValid()) {
      continue;
    }

    CharacterActionDefinition definition;
    definition.actionId = actionId;
    while (!actionStream.IsEnd()) {
      std::string token = toLower(actionStream.Next());
      if (token.empty()) {
        break;
      }

      if (token == "[action id]") {
        definition.actionId = toLower(trim(actionStream.Next()));
      } else if (token == "[animation tag]") {
        definition.animationTag = trim(actionStream.Next());
      } else if (token == "[total frames]") {
        definition.totalFrames = toInt(actionStream.Next(), definition.totalFrames);
      } else if (token == "[loop]") {
        definition.loop = isTrueToken(actionStream.Next());
      } else if (token == "[can move]") {
        definition.canMove = isTrueToken(actionStream.Next());
      } else if (token == "[can turn]") {
        definition.canTurn = isTrueToken(actionStream.Next());
      } else if (token == "[can be interrupted]") {
        definition.canBeInterrupted = isTrueToken(actionStream.Next());
      } else if (token == "[move speed scale]") {
        definition.moveSpeedScale = toFloat(actionStream.Next(), definition.moveSpeedScale);
      } else if (token == "[cancel rule]") {
        CharacterCancelRuleDefinition rule;
        rule.targetAction = toLower(trim(actionStream.Next()));
        rule.beginFrame = toInt(actionStream.Next(), 0);
        rule.endFrame = toInt(actionStream.Next(), rule.beginFrame);
        rule.requireGrounded = isTrueToken(actionStream.Next());
        rule.requireAirborne = isTrueToken(actionStream.Next());
        definition.cancelRules.push_back(rule);
      } else if (token == "[frame event]") {
        CharacterFrameEventDefinition frameEvent;
        frameEvent.frame = toInt(actionStream.Next(), 0);
        frameEvent.type = parseFrameEventType(trim(actionStream.Next()));
        if (frameEvent.type == CharacterFrameEventType::SetVelocityXY) {
          frameEvent.velocityXY.x = toFloat(actionStream.Next(), 0.0f);
          frameEvent.velocityXY.y = toFloat(actionStream.Next(), 0.0f);
        } else if (frameEvent.type == CharacterFrameEventType::SetVelocityZ) {
          frameEvent.velocityZ = toFloat(actionStream.Next(), 0.0f);
        } else {
          frameEvent.stringValue = trim(actionStream.Next());
        }
        definition.frameEvents.push_back(frameEvent);
      }
    }

    addOrReplaceAction(actions_, std::move(definition));
  }

  return true;
}

std::optional<CharacterActionLibrary> loadCharacterActionLibrary(
    const character::CharacterConfig& config) {
  CharacterActionLibrary library;
  if (!library.LoadForConfig(config)) {
    return std::nullopt;
  }
  return library;
}

} // namespace frostbite2D