#include "animate2.hpp"
#include <memory>
#include <chrono>
#include "dbc.hpp"
#include "rand.hpp"

namespace animate2 {
  std::vector<sf::IntRect> Animate2::calc_frames() {
    std::vector<sf::IntRect> frames;

    for(int frame_i : $sequence.frames) {
      frames.emplace_back(
          sf::Vector2i{$sheet.frame_width * frame_i, 0}, // NOTE: one row only for now
          sf::Vector2i{$sheet.frame_width,
          $sheet.frame_height});
    }

    return frames;
  }

  void Animate2::play() {
    dbc::check(!playing, "can't call play while playing?");
    $sequence.current = 0;
    $sequence.subframe = 0.0f;
    $sequence.loop_count = 0;
    playing = true;
    $sequence.timer.start();
  }

  void Animate2::stop() {
    playing = false;
    $sequence.timer.reset();
  }

  // need one for each kind of thing to animate
  // NOTE: possibly find a way to only run apply on frame change?
  void Animate2::apply(sf::Sprite& sprite) {
    dbc::check($sequence.current < $frame_rects.size(), "current frame past $frame_rects");
    // NOTE: pos is not updated yet
    auto& rect = $frame_rects.at($sequence.current);
    sprite.setTextureRect(rect);
  }

  // replaces step
  void Animate2::update_frame() {
    dbc::check(playing, "attempt to update animation that's not playing");
    dbc::check($sequence.frame_count == $sequence.frames.size(), "frame_count doesn't match frame.size()");

    auto duration = $sequence.durations.at($sequence.current);
    bool frame_change = false;

    if($sequence.timer.getElapsedTime() >= duration) {
      $sequence.timer.restart();
      $sequence.current++;
      frame_change = true;
    }

    if($sequence.current >= $sequence.frame_count) {
      $sequence.loop_count++;
      playing = onLoop($sequence, $transform);
    }

    if(frame_change && onFrame != nullptr) onFrame();

    dbc::check($sequence.current < $sequence.frame_count, "onLoop fail: current frame out of frames.size()");
  }

  void Animate2::update() {
    $sequence.subframe += $transform.speed;
    update_frame();
  }

  void Animate2::motion(sf::Vector2f& pos, sf::Vector2f& scale) {
    $transform.twitching($sequence);
    $transform.lerp($sequence, pos, scale);
  }

  float Transform::twitching(Sequence& seq) {
    float tick = 1 - std::powf(ease_rate, seq.subframe + 0.0001);

    switch(easing) {
      case ease::NONE:
        return 0.0;
      case ease::SINE:
        return std::abs(std::sin(seq.subframe * ease_rate));
      case ease::OUT_CIRC:
        return ease::out_circ(tick);
      case ease::OUT_BOUNCE:
        return ease::out_bounce(tick);
      case ease::IN_OUT_BACK:
        return ease::in_out_back(tick);
      case ease::RANDOM:
        return Random::uniform_real(0.0001f, 1.0f);
      case ease::NORM_DIST:
        return Random::normal(0.5f, 0.1f);
      case ease::LINEAR:
        return tick;
      default:
        dbc::sentinel(
            fmt::format("Invalid easing {} given to animation",
              int(easing)));
    }
  }

  void Transform::lerp(Sequence& seq, sf::Vector2f& pos_out, sf::Vector2f& scale_out) {
    float tick = twitching(seq);

    if(stationary) {
      switch(motion) {
        case ease::SHAKE: {
          pos_out.x += std::lerp(min_x, max_x, tick);
         } break;
        case ease::BOUNCE: {
          pos_out.y -= std::lerp(min_y, max_y, tick);
        } break;
        case ease::RUSH: {
          scale_out.x = std::lerp(min_x, max_x, tick);
          scale_out.y = std::lerp(min_y, max_y, tick);
          pos_out.y = pos_out.y - (pos_out.y * scale_out.y - pos_out.y);
         } break;
        case ease::SQUEEZE: {
          scale_out.x *= std::lerp(min_x, max_x, tick);
        } break;
        case ease::SQUASH: {
          scale_out.y *= std::lerp(min_y, max_y, tick);
        } break;
        case ease::STRETCH: {
          scale_out.x = std::lerp(min_x, max_x, tick);
        } break;
        case ease::GROW: {
          scale_out.y = std::lerp(min_y, max_y, tick);
        } break;
        case ease::SLIDE: {
          pos_out.x = std::lerp(min_x, max_x, tick);
          pos_out.y = std::lerp(min_y, max_y, tick);
        } break;
        default:
          dbc::sentinel("Unknown animation.motion setting.");
      }
    } else {
      dbc::sentinel("scale should not run");
      scale_out.x = std::lerp(scale_out.x * min_x, scale_out.x * max_x, tick);
      scale_out.y = std::lerp(scale_out.y * min_y, scale_out.y * max_y, tick);
    }
  }
}