package funkin.play.character;

import flixel.util.typeLimit.OneOfTwo;
import funkin.modding.events.ScriptEvent;
import funkin.modding.events.ScriptEventDispatcher;
import funkin.play.character.BaseCharacter;
import funkin.play.character.MultiSparrowCharacter;
import funkin.play.character.PackerCharacter;
import funkin.play.character.ScriptedCharacter.ScriptedBaseCharacter;
import funkin.play.character.ScriptedCharacter.ScriptedMultiSparrowCharacter;
import funkin.play.character.ScriptedCharacter.ScriptedPackerCharacter;
import funkin.play.character.ScriptedCharacter.ScriptedSparrowCharacter;
import funkin.play.character.SparrowCharacter;
import funkin.util.VersionUtil;
import funkin.util.assets.DataAssets;
import haxe.Json;
import openfl.utils.Assets;

class CharacterDataParser
{
  /**
   * The current version string for the stage data format.
   * Handle breaking changes by incrementing this value
   * and adding migration to the `migrateStageData()` function.
   */
  public static final CHARACTER_DATA_VERSION:String = "1.0.0";

  /**
   * The current version rule check for the stage data format.
   */
  public static final CHARACTER_DATA_VERSION_RULE:String = "1.0.x";

  static final characterCache:Map<String, CharacterData> = new Map<String, CharacterData>();
  static final characterScriptedClass:Map<String, String> = new Map<String, String>();

  static final DEFAULT_CHAR_ID:String = 'UNKNOWN';

  /**
   * Parses and preloads the game's stage data and scripts when the game starts.
   * 
   * If you want to force stages to be reloaded, you can just call this function again.
   */
  public static function loadCharacterCache():Void
  {
    // Clear any stages that are cached if there were any.
    clearCharacterCache();
    trace("Loading character cache...");

    //
    // UNSCRIPTED CHARACTERS
    //
    var charIdList:Array<String> = DataAssets.listDataFilesInPath('characters/');
    var unscriptedCharIds:Array<String> = charIdList.filter(function(charId:String):Bool
    {
      return !characterCache.exists(charId);
    });
    trace('  Fetching data for ${unscriptedCharIds.length} characters...');
    for (charId in unscriptedCharIds)
    {
      try
      {
        var charData:CharacterData = parseCharacterData(charId);
        if (charData != null)
        {
          trace('    Loaded character data: ${charId}');
          characterCache.set(charId, charData);
        }
      }
      catch (e)
      {
        // Assume error was already logged.
        continue;
      }
    }

    //
    // SCRIPTED CHARACTERS
    //

    // Fuck I wish scripted classes supported static functions.

    var scriptedCharClassNames1:Array<String> = ScriptedSparrowCharacter.listScriptClasses();
    if (scriptedCharClassNames1.length > 0)
    {
      trace('  Instantiating ${scriptedCharClassNames1.length} (Sparrow) scripted characters...');
      for (charCls in scriptedCharClassNames1)
      {
        var character = ScriptedSparrowCharacter.init(charCls, DEFAULT_CHAR_ID);
        characterScriptedClass.set(character.characterId, charCls);
      }
    }

    var scriptedCharClassNames2:Array<String> = ScriptedPackerCharacter.listScriptClasses();
    if (scriptedCharClassNames2.length > 0)
    {
      trace('  Instantiating ${scriptedCharClassNames2.length} (Packer) scripted characters...');
      for (charCls in scriptedCharClassNames2)
      {
        var character = ScriptedPackerCharacter.init(charCls, DEFAULT_CHAR_ID);
        characterScriptedClass.set(character.characterId, charCls);
      }
    }

    var scriptedCharClassNames3:Array<String> = ScriptedMultiSparrowCharacter.listScriptClasses();
    if (scriptedCharClassNames3.length > 0)
    {
      trace('  Instantiating ${scriptedCharClassNames3.length} (Multi-Sparrow) scripted characters...');
      for (charCls in scriptedCharClassNames3)
      {
        var character = ScriptedMultiSparrowCharacter.init(charCls, DEFAULT_CHAR_ID);
        if (character == null)
        {
          trace('    Failed to instantiate scripted character: ${charCls}');
          continue;
        }
        characterScriptedClass.set(character.characterId, charCls);
      }
    }

    // NOTE: Only instantiate the ones not populated above.
    // ScriptedBaseCharacter.listScriptClasses() will pick up scripts extending the other classes.
    var scriptedCharClassNames:Array<String> = ScriptedBaseCharacter.listScriptClasses();
    scriptedCharClassNames = scriptedCharClassNames.filter(function(charCls:String):Bool
    {
      return !(scriptedCharClassNames1.contains(charCls)
        || scriptedCharClassNames2.contains(charCls)
        || scriptedCharClassNames3.contains(charCls));
    });

    if (scriptedCharClassNames.length > 0)
    {
      trace('  Instantiating ${scriptedCharClassNames.length} (Base) scripted characters...');
      for (charCls in scriptedCharClassNames)
      {
        var character = ScriptedBaseCharacter.init(charCls, DEFAULT_CHAR_ID);
        if (character == null)
        {
          trace('    Failed to instantiate scripted character: ${charCls}');
          continue;
        }
        else
        {
          trace('    Successfully instantiated scripted character: ${charCls}');
          characterScriptedClass.set(character.characterId, charCls);
        }
      }
    }

    trace('  Successfully loaded ${Lambda.count(characterCache)} stages.');
  }

  public static function fetchCharacter(charId:String):Null<BaseCharacter>
  {
    if (charId == null || charId == '')
    {
      // Gracefully handle songs that don't use this character.
      return null;
    }

    if (characterCache.exists(charId))
    {
      var charData:CharacterData = characterCache.get(charId);
      var charScriptClass:String = characterScriptedClass.get(charId);

      var char:BaseCharacter;

      if (charScriptClass != null)
      {
        switch (charData.renderType)
        {
          case CharacterRenderType.MULTISPARROW:
            char = ScriptedMultiSparrowCharacter.init(charScriptClass, charId);
          case CharacterRenderType.SPARROW:
            char = ScriptedSparrowCharacter.init(charScriptClass, charId);
          case CharacterRenderType.PACKER:
            char = ScriptedPackerCharacter.init(charScriptClass, charId);
          default:
            // We're going to assume that the script class does the rendering.
            char = ScriptedBaseCharacter.init(charScriptClass, charId);
        }
      }
      else
      {
        switch (charData.renderType)
        {
          case CharacterRenderType.MULTISPARROW:
            char = new MultiSparrowCharacter(charId);
          case CharacterRenderType.SPARROW:
            char = new SparrowCharacter(charId);
          case CharacterRenderType.PACKER:
            char = new PackerCharacter(charId);
          default:
            trace('[WARN] Creating character with undefined renderType ${charData.renderType}');
            char = new BaseCharacter(charId);
        }
      }

      trace('Successfully instantiated character: ${charId}');

      // Call onCreate only in the fetchCharacter() function, not at application initialization.
      ScriptEventDispatcher.callEvent(char, new ScriptEvent(ScriptEvent.CREATE));

      return char;
    }
    else
    {
      trace('Failed to build character, not found in cache: ${charId}');
      return null;
    }
  }

  public static function fetchCharacterData(charId:String):Null<CharacterData>
  {
    if (characterCache.exists(charId))
    {
      return characterCache.get(charId);
    }
    else
    {
      return null;
    }
  }

  public static function listCharacterIds():Array<String>
  {
    return characterCache.keys().array();
  }

  static function clearCharacterCache():Void
  {
    if (characterCache != null)
    {
      characterCache.clear();
    }
    if (characterScriptedClass != null)
    {
      characterScriptedClass.clear();
    }
  }

  /**
   * Load a character's JSON file, parse its data, and return it.
   * 
   * @param charId The character to load.
   * @return The character data, or null if validation failed.
   */
  public static function parseCharacterData(charId:String):Null<CharacterData>
  {
    var rawJson:String = loadCharacterFile(charId);

    var charData:CharacterData = migrateCharacterData(rawJson, charId);

    return validateCharacterData(charId, charData);
  }

  static function loadCharacterFile(charPath:String):String
  {
    var charFilePath:String = Paths.json('characters/${charPath}');
    var rawJson = Assets.getText(charFilePath).trim();

    while (!StringTools.endsWith(rawJson, "}"))
    {
      rawJson = rawJson.substr(0, rawJson.length - 1);
    }

    return rawJson;
  }

  static function migrateCharacterData(rawJson:String, charId:String)
  {
    // If you update the character data format in a breaking way,
    // handle migration here by checking the `version` value.

    try
    {
      var charData:CharacterData = cast Json.parse(rawJson);
      return charData;
    }
    catch (e)
    {
      trace('  Error parsing data for character: ${charId}');
      trace('    ${e}');
      return null;
    }
  }

  /**
   * The default time the character should sing for, in beats.
   * Values that are too low will cause the character to stop singing between notes.
   * Originally, this value was set to 1, but it was changed to 2 because that became
   * too low after some other code changes.
   */
  static final DEFAULT_SINGTIME:Float = 2.0;

  static final DEFAULT_DANCEEVERY:Int = 1;
  static final DEFAULT_FLIPX:Bool = false;
  static final DEFAULT_FLIPY:Bool = false;
  static final DEFAULT_FRAMERATE:Int = 24;
  static final DEFAULT_ISPIXEL:Bool = false;
  static final DEFAULT_LOOP:Bool = false;
  static final DEFAULT_NAME:String = "Untitled Character";
  static final DEFAULT_OFFSETS:Array<Float> = [0, 0];
  static final DEFAULT_HEALTHICON_OFFSETS:Array<Int> = [0, 25];
  static final DEFAULT_RENDERTYPE:CharacterRenderType = CharacterRenderType.SPARROW;
  static final DEFAULT_SCALE:Float = 1;
  static final DEFAULT_SCROLL:Array<Float> = [0, 0];
  static final DEFAULT_STARTINGANIM:String = "idle";

  /**
   * Set unspecified parameters to their defaults.
   * If the parameter is mandatory, print an error message.
   * @param id 
   * @param input 
   * @return The validated character data
   */
  static function validateCharacterData(id:String, input:CharacterData):Null<CharacterData>
  {
    if (input == null)
    {
      // trace('ERROR: Could not parse character data for "${id}".');
      return null;
    }

    if (input.version == null)
    {
      trace('WARN: No semantic version specified for character data file "$id", assuming ${CHARACTER_DATA_VERSION}');
      input.version = CHARACTER_DATA_VERSION;
    }

    if (!VersionUtil.validateVersion(input.version, CHARACTER_DATA_VERSION_RULE))
    {
      trace('ERROR: Could not load character data for "$id": bad version (got ${input.version}, expected ${CHARACTER_DATA_VERSION_RULE})');
      return null;
    }

    if (input.name == null)
    {
      trace('WARN: Character data for "$id" missing name');
      input.name = DEFAULT_NAME;
    }

    if (input.renderType == null)
    {
      input.renderType = DEFAULT_RENDERTYPE;
    }

    if (input.assetPath == null)
    {
      trace('ERROR: Could not load character data for "$id": missing assetPath');
      return null;
    }

    if (input.offsets == null)
    {
      input.offsets = DEFAULT_OFFSETS;
    }

    if (input.cameraOffsets == null)
    {
      input.cameraOffsets = DEFAULT_OFFSETS;
    }

    if (input.healthIcon == null)
    {
      input.healthIcon = {
        id: null,
        scale: null,
        flipX: null,
        offsets: null
      };
    }

    if (input.healthIcon.id == null)
    {
      input.healthIcon.id = id;
    }

    if (input.healthIcon.scale == null)
    {
      input.healthIcon.scale = DEFAULT_SCALE;
    }

    if (input.healthIcon.flipX == null)
    {
      input.healthIcon.flipX = DEFAULT_FLIPX;
    }

    if (input.healthIcon.offsets == null)
    {
      input.healthIcon.offsets = DEFAULT_OFFSETS;
    }

    if (input.startingAnimation == null)
    {
      input.startingAnimation = DEFAULT_STARTINGANIM;
    }

    if (input.scale == null)
    {
      input.scale = DEFAULT_SCALE;
    }

    if (input.isPixel == null)
    {
      input.isPixel = DEFAULT_ISPIXEL;
    }

    if (input.danceEvery == null)
    {
      input.danceEvery = DEFAULT_DANCEEVERY;
    }

    if (input.singTime == null)
    {
      input.singTime = DEFAULT_SINGTIME;
    }

    if (input.animations == null || input.animations.length == 0)
    {
      trace('ERROR: Could not load character data for "$id": missing animations');
      input.animations = [];
    }

    if (input.flipX == null)
    {
      input.flipX = DEFAULT_FLIPX;
    }

    if (input.animations.length == 0 && input.startingAnimation != null)
    {
      return null;
    }

    for (inputAnimation in input.animations)
    {
      if (inputAnimation.name == null)
      {
        trace('ERROR: Could not load character data for "$id": missing animation name for prop "${input.name}"');
        return null;
      }

      if (inputAnimation.frameRate == null)
      {
        inputAnimation.frameRate = DEFAULT_FRAMERATE;
      }

      if (inputAnimation.offsets == null)
      {
        inputAnimation.offsets = DEFAULT_OFFSETS;
      }

      if (inputAnimation.looped == null)
      {
        inputAnimation.looped = DEFAULT_LOOP;
      }

      if (inputAnimation.flipX == null)
      {
        inputAnimation.flipX = DEFAULT_FLIPX;
      }

      if (inputAnimation.flipY == null)
      {
        inputAnimation.flipY = DEFAULT_FLIPY;
      }
    }

    // All good!
    return input;
  }
}

enum abstract CharacterRenderType(String) from String to String
{
  var SPARROW = 'sparrow';
  var PACKER = 'packer';
  var MULTISPARROW = 'multisparrow';
  // TODO: FlxSpine?
  //   https://api.haxeflixel.com/flixel/addons/editors/spine/FlxSpine.html
  // TODO: Aseprite?
  //   https://lib.haxe.org/p/openfl-aseprite/
  // TODO: Animate?
  //   https://lib.haxe.org/p/flxanimate
  // TODO: REDACTED
}

typedef CharacterData =
{
  /**
   * The sematic version number of the character data JSON format.
   */
  var version:String;

  /**
   * The readable name of the character.
   */
  var name:String;

  /**
   * The type of rendering system to use for the character.
   * @default sparrow
   */
  var renderType:CharacterRenderType;

  /**
   * Behavior varies by render type:
   * - SPARROW: Path to retrieve both the spritesheet and the XML data from.
   * - PACKER: Path to retrieve both the spritsheet and the TXT data from.
   */
  var assetPath:String;

  /**
   * The scale of the graphic as a float.
   * Pro tip: On pixel-art levels, save the sprites small and set this value to 6 or so to save memory.
   * @default 1
   */
  var scale:Null<Float>;

  /**
   * Optional data about the health icon for the character.
   */
  var healthIcon:Null<HealthIconData>;

  /**
   * The global offset to the character's position, in pixels.
   * @default [0, 0]
   */
  var offsets:Null<Array<Float>>;

  /**
   * The amount to offset the camera by while focusing on this character.
   * Default value focuses on the character directly.
   * @default [0, 0]
   */
  var cameraOffsets:Array<Float>;

  /**
   * Setting this to true disables anti-aliasing for the character.
   * @default false
   */
  var isPixel:Null<Bool>;

  /**
   * The frequency at which the character will play its idle animation, in beats.
   * Increasing this number will make the character dance less often.
   * 
   * @default 1
   */
  var danceEvery:Null<Int>;

  /**
   * The minimum duration that a character will play a note animation for, in beats.
   * If this number is too low, you may see the character start playing the idle animation between notes.
   * If this number is too high, you may see the the character play the sing animation for too long after the notes are gone.
   * 
   * Examples:
   * - Daddy Dearest uses a value of `1.525`.
   * @default 1.0
   */
  var singTime:Null<Float>;

  /**
   * An optional array of animations which the character can play.
   */
  var animations:Array<AnimationData>;

  /**
   * If animations are used, this is the name of the animation to play first.
   * @default idle
   */
  var startingAnimation:Null<String>;

  /**
   * Whether or not the whole ass sprite is flipped by default.
   * Useful for characters that could also be played (Pico)
   * 
   * @default false
   */
  var flipX:Null<Bool>;
};

typedef HealthIconData =
{
  /**
   * The ID to use for the health icon.
   * @default The character's ID
   */
  var id:Null<String>;

  /**
   * The scale of the health icon.
   */
  var scale:Null<Float>;

  /**
   * Whether to flip the health icon horizontally.
   * @default false
   */
  var flipX:Null<Bool>;

  /**
   * The offset of the health icon, in pixels.
   * @default [0, 25]
   */
  var offsets:Null<Array<Float>>;
}