#include "animation_system.h"
#include <fstream>
#include <string>
#include <list>
#include "game.h"
#include "vector.h"
#include "util.h"

void AnimationSystem::initSprite(int spriteId, std::string_view filename) {
  std::ifstream datafile(filename.data());
  if (!datafile.is_open()) {
    throw std::invalid_argument(std::string("Could not find sprite datafile: ") + std::string(filename));
  }

  Sprite& sprite = game_.getSprite(spriteId);
  sprite.isAnimated = true;

  char ch;
  std::string line;

  datafile >> sprite.spritesheet;

  std::string framefilename;
  datafile >> framefilename;

  std::ifstream framefile(framefilename);
  if (!framefile.is_open()) {
    throw std::invalid_argument("Could not find frame datafile: " + framefilename);
  }

  vec2i cellSize;
  framefile >> cellSize.w();
  framefile >> ch; //,
  framefile >> cellSize.h();
  std::getline(framefile, line); // cell size

  int framesPerRow;
  framefile >> framesPerRow;
  std::getline(framefile, line); // frames per row

  int numFrames;
  framefile >> numFrames;
  std::getline(framefile, line); // frames
  std::getline(framefile, line); // blank

  sprite.frames.clear();
  for (int i=0; i<numFrames; i++) {
    SpriteFrame f;
    framefile >> f.size.w();
    framefile >> ch; //,
    framefile >> f.size.h();
    framefile >> ch; //,
    framefile >> f.center.x();
    framefile >> ch; //,
    framefile >> f.center.y();
    std::getline(framefile, line); // blank

    f.srcRect.x = (i % framesPerRow) * cellSize.w();
    f.srcRect.y = (i / framesPerRow) * cellSize.h();
    f.srcRect.w = f.size.w();
    f.srcRect.h = f.size.h();

    sprite.frames.push_back(std::move(f));
  }

  std::string animLine;
  std::getline(datafile, animLine); // blank
  sprite.animations.clear();
  sprite.nameDirToAnim.clear();
  while (std::getline(datafile, animLine)) {
    std::regex re(R"(([a-z!._]+)\[([a-z_]+)\](%[0-9]+)?: ([0-9,#]+))");
    std::smatch m;
    std::regex_match(animLine, m, re);

    std::string animName = m[1];
    Animation anim;
    auto framestrs = splitStr<std::list<std::string>>(m[4], ",");
    for (const std::string& f : framestrs) {
      int times = 1;
      size_t repeat_it = f.find("#");
      if (repeat_it != std::string::npos) {
        times = std::stoi(f.substr(repeat_it + 1));
      }

      for (int i=0; i<times; i++) {
        anim.frameIndices.push_back(std::stoi(f));
      }
    }

    if (animName.back() == '!') {
      anim.looping = false;
    }

    if (m[3] != "") {
      int frameRate = std::stoi(std::string(m[3]).substr(1));
      switch (frameRate) {
        case 5: anim.timerNum = 0; break;
        case 60: anim.timerNum = 1; break;
        default: throw std::invalid_argument("Invalid frame rate");
      }
    }

    int animId = sprite.animations.size();
    sprite.animations.push_back(std::move(anim));

    Direction dir = directionFromString(std::string(m[2]));
    sprite.nameDirToAnim[animName][dir] = animId;
  }

  updateAnimation(spriteId);
}

void AnimationSystem::tick(double dt) {
  if (game_.isGameplayPaused()) return;

  for (int timerNum = 0; timerNum < animTimers_.size(); timerNum++) {
    Timer& animTimer = animTimers_[timerNum];

    animTimer.accumulate(dt);
    while (animTimer.step()) {
      for (Sprite& sprite : game_.getSprites() | game_.spriteView()) {
        if (sprite.isAnimated &&
            sprite.animations[sprite.animationId].timerNum == timerNum &&
            !sprite.animFinished &&
            !sprite.animPaused) {
          if (sprite.animSlowdown > 1) {
            sprite.animSlowdownProgress++;

            if (sprite.animSlowdownProgress == sprite.animSlowdown) {
              sprite.animSlowdownProgress = 0;
            } else {
              continue;
            }
          }

          sprite.animationFrame++;

          if (sprite.animationFrame >= sprite.animations[sprite.animationId].frameIndices.size()) {
            if (sprite.animations[sprite.animationId].looping) {
              sprite.animationFrame = 0;
            } else {
              sprite.animFinished = true;
              sprite.animationFrame = sprite.animations[sprite.animationId].frameIndices.size() - 1;
            }
          }
        }
      }
    }
  }

  bobbingTimer_.accumulate(dt);
  while (bobbingTimer_.step()) {
    for (Sprite& sprite : game_.getSprites() | game_.spriteView()) {
      if (sprite.isAnimated && sprite.bobbing) {
        if (sprite.bobbingDown) {
          sprite.bobAmount--;
          if (sprite.bobAmount == 0) {
            sprite.bobbingDown = false;
          }
        } else {
          sprite.bobAmount++;
          if (sprite.bobAmount == 4) {
            sprite.bobbingDown = true;
          }
        }
      }
    }
  }

  fadingTimer_.accumulate(dt);
  while (fadingTimer_.step()) {
    for (Sprite& sprite : game_.getSprites() | game_.spriteView()) {
      if (sprite.isAnimated) {
        if (sprite.shouldBeFadedIn && sprite.opacity < 1.0) {
          sprite.opacity += 0.05;
          if (sprite.opacity > 1.0) {
            sprite.opacity = 1.0;
          }
        } else if (!sprite.shouldBeFadedIn && sprite.opacity > 0.0) {
          sprite.opacity -= 0.05;
          if (sprite.opacity < 0.0) {
            sprite.opacity = 0.0;
          }
        }
      }
    }
  }
}

void AnimationSystem::setSpriteDirection(int spriteId, Direction dir) {
  Sprite& sprite = game_.getSprite(spriteId);
  if (sprite.dir != dir) {
    sprite.dir = dir;
    updateAnimation(spriteId);
  }
}

void AnimationSystem::setSpriteAnimation(int spriteId, std::string_view name) {
  Sprite& sprite = game_.getSprite(spriteId);
  if (sprite.animationName != name) {
    sprite.animationName = name;
    updateAnimation(spriteId);
  }
}

void AnimationSystem::updateAnimation(int spriteId) {
  Sprite& sprite = game_.getSprite(spriteId);
  sprite.animationId = sprite.nameDirToAnim[sprite.animationName][sprite.dir];
  sprite.animationFrame = 0;
  sprite.animFinished = false;
  sprite.animPaused = false;
  sprite.animSlowdownProgress = 0;
}