package gfx

import (
	"image"
	"io/fs"
	"os"
	"path/filepath"

	"github.com/chompy/roguelike_rpg/internal/util"
	"github.com/hajimehoshi/ebiten/v2"
)

type SpriteDef struct {
	Path     string   `yaml:"path"`
	TileSize [2]int   `yaml:"size"`
	Frames   []int    `yaml:"frames"`
	FPS      int      `yaml:"fps"`
	Loop     bool     `yaml:"loop"`
	Effects  []string `yaml:"effects"`
}

type SpriteLibrary map[string]*Sprite

func LoadSpriteLibrary(assetFS fs.FS) (SpriteLibrary, error) {
	// load sprites.yaml
	spriteLibraryConf := make(map[string]SpriteDef)
	if err := util.ReadYAML(assetFS, filepath.Join("gfx", "sprites.yaml"), &spriteLibraryConf); err != nil {
		return nil, err
	}

	// preload all sprite images and visual effects
	spriteImages := make(map[string]image.Image)
	effects := make(map[string]Effect)
	for _, spriteDef := range spriteLibraryConf {
		if spriteImages[spriteDef.Path] == nil && spriteDef.Path != "" {
			spriteImage, err := LoadImage(assetFS, spriteDef.Path)
			if err != nil {
				return nil, err
			}
			spriteImages[spriteDef.Path] = spriteImage
		}
		for _, effectName := range spriteDef.Effects {
			if effects[effectName] == nil {
				luaEffect, err := LoadLuaEffect(assetFS, effectName)
				if err != nil && !os.IsNotExist(err) {
					return nil, err
				}
				if err == nil {
					effects[effectName] = luaEffect
					continue
				}

				shaderEffect, err := LoadShaderEffect(assetFS, effectName)
				if err != nil && !os.IsNotExist(err) {
					return nil, err
				}
				if err == nil {
					effects[effectName] = shaderEffect
					continue
				}
			}
		}
	}

	// load sprites in to library
	spriteLibrary := make(SpriteLibrary, 0)
	for name, spriteDef := range spriteLibraryConf {
		if spriteImages[spriteDef.Path] != nil {
			spriteLibrary[name] = &Sprite{
				image:           ebiten.NewImageFromImage(spriteImages[spriteDef.Path]),
				tileSize:        spriteDef.TileSize,
				animationFrames: spriteDef.Frames,
				animationFPS:    spriteDef.FPS,
				loop:            spriteDef.Loop,
				effects:         make([]Effect, 0),
			}
			for _, effectName := range spriteDef.Effects {
				if effects[effectName] != nil {
					spriteLibrary[name].effects = append(spriteLibrary[name].effects, effects[effectName])
				}
			}
		}
	}
	return spriteLibrary, nil
}

func (l SpriteLibrary) Get(names ...string) ([]*Sprite, error) {
	out := make([]*Sprite, 0)
	for _, name := range names {
		if l[name] != nil {
			out = append(out, l[name])
		}
	}
	if len(out) == 0 {
		return out, ErrSpriteNotDefined
	}
	return out, nil
}

func (l SpriteLibrary) GetOne(name string) (*Sprite, error) {
	if l[name] != nil {
		return l[name], nil
	}
	return nil, ErrSpriteNotDefined
}

func (l SpriteLibrary) GetFirst(names ...string) (*Sprite, error) {
	sprites, err := l.Get(names...)
	if err != nil {
		return nil, err
	}
	return sprites[0], nil
}