package yggdrasil

import (
	"context"
	"crypto/sha256"
	"encoding/hex"
	"errors"
	"fmt"
	"os"
	"path/filepath"

	"github.com/samber/lo"
	"github.com/xmdhs/authlib-skin/db/ent"
	"github.com/xmdhs/authlib-skin/db/ent/texture"
	"github.com/xmdhs/authlib-skin/db/ent/user"
	"github.com/xmdhs/authlib-skin/db/ent/userprofile"
	"github.com/xmdhs/authlib-skin/db/ent/usertexture"
	"github.com/xmdhs/authlib-skin/model"
	"github.com/xmdhs/authlib-skin/utils"
)

var (
	ErrUUIDNotEq = errors.New("uuid 不相同")
)

func (y *Yggdrasil) delTexture(ctx context.Context, userProfileID int, textureType string) error {
	// 查找此用户该类型下是否已经存在皮肤
	tl, err := y.client.UserTexture.Query().Where(usertexture.And(
		usertexture.UserProfileID(userProfileID),
		usertexture.Type(textureType),
	)).All(ctx)
	if err != nil {
		return fmt.Errorf("delTexture: %w", err)
	}
	if len(tl) == 0 {
		return nil
	}
	// 若存在，查找是否被引用
	for _, v := range tl {
		c, err := y.client.UserTexture.Query().Where(usertexture.TextureID(v.TextureID)).Count(ctx)
		if err != nil {
			return fmt.Errorf("delTexture: %w", err)
		}
		if c == 1 {
			// 若没有其他用户使用该皮肤，删除文件和记录
			t, err := y.client.Texture.Query().Where(texture.ID(v.TextureID)).Only(ctx)
			if err != nil {
				var nf *ent.NotFoundError
				if errors.As(err, &nf) {
					continue
				}
				return fmt.Errorf("delTexture: %w", err)
			}
			path := filepath.Join(y.config.TexturePath, t.TextureHash[:2], t.TextureHash[2:4], t.TextureHash)
			err = os.Remove(path)
			if err != nil && !errors.Is(err, os.ErrNotExist) {
				return fmt.Errorf("delTexture: %w", err)
			}
			// Texture 表中删除记录
			err = y.client.Texture.DeleteOneID(v.TextureID).Exec(ctx)
			if err != nil {
				return fmt.Errorf("delTexture: %w", err)
			}
		}
	}
	ids := lo.Map[*ent.UserTexture, int](tl, func(item *ent.UserTexture, index int) int {
		return item.ID
	})
	// 中间表删除记录
	// UserProfile 上没有于此相关的字段，所以无需操作
	_, err = y.client.UserTexture.Delete().Where(usertexture.IDIn(ids...)).Exec(ctx)
	// 小概率皮肤上传后，高并发时被此处清理。问题不大重新上传一遍就行。
	// 条件为使用一个独一无二的皮肤的用户，更换皮肤时，另一个用户同时更换自己的皮肤到这个独一无二的皮肤上。
	if err != nil {
		return fmt.Errorf("delTexture: %w", err)
	}
	return nil
}

func (y *Yggdrasil) DelTexture(ctx context.Context, uuid string, t *model.TokenClaims, textureType string) error {
	if uuid != t.Subject {
		return fmt.Errorf("PutTexture: %w", ErrUUIDNotEq)
	}
	up, err := y.client.UserProfile.Query().Where(userprofile.HasUserWith(user.ID(t.UID))).First(ctx)
	if err != nil {
		return fmt.Errorf("DelTexture: %w", err)
	}
	err = y.delTexture(ctx, up.ID, textureType)
	if err != nil {
		return fmt.Errorf("DelTexture: %w", err)
	}
	err = y.cache.Del([]byte("Profile" + uuid))
	if err != nil {
		return fmt.Errorf("DelTexture: %w", err)
	}
	return nil
}

func (y *Yggdrasil) PutTexture(ctx context.Context, t *model.TokenClaims, texturebyte []byte, model string, uuid string, textureType string) error {
	if uuid != t.Subject {
		return fmt.Errorf("PutTexture: %w", ErrUUIDNotEq)
	}

	up, err := y.client.UserProfile.Query().Where(userprofile.HasUserWith(user.ID(t.UID))).First(ctx)
	if err != nil {
		return fmt.Errorf("PutTexture: %w", err)
	}

	err = y.delTexture(ctx, up.ID, textureType)
	if err != nil {
		return fmt.Errorf("PutTexture: %w", err)
	}

	hashstr := getHash(texturebyte)
	if err != nil {
		return fmt.Errorf("PutTexture: %w", err)
	}
	u, err := y.client.User.Query().Where(user.HasProfileWith(userprofile.ID(up.ID))).Only(ctx)
	if err != nil {
		return fmt.Errorf("PutTexture: %w", err)
	}

	err = utils.WithTx(ctx, y.client, func(tx *ent.Tx) error {
		t, err := tx.Texture.Query().Where(texture.TextureHash(hashstr)).Only(ctx)
		if err != nil {
			var ne *ent.NotFoundError
			if !errors.As(err, &ne) {
				return err
			}
		}
		if t == nil {
			t, err = tx.Texture.Create().SetCreatedUser(u).SetTextureHash(hashstr).Save(ctx)
			if err != nil {
				return err
			}
		}
		err = tx.UserTexture.Create().SetTexture(t).SetType(textureType).SetUserProfile(up).SetVariant(model).Exec(ctx)
		if err != nil {
			return err
		}
		return nil
	})
	if err != nil {
		return fmt.Errorf("PutTexture: %w", err)
	}
	err = createTextureFile(y.config.TexturePath, texturebyte, hashstr)
	if err != nil {
		return fmt.Errorf("PutTexture: %w", err)
	}
	err = y.cache.Del([]byte("Profile" + uuid))
	if err != nil {
		return fmt.Errorf("PutTexture: %w", err)
	}
	return nil
}

func getHash(b []byte) string {
	hashed := sha256.Sum256(b)
	return hex.EncodeToString(hashed[:])
}

func createTextureFile(path string, b []byte, hashstr string) error {
	p := filepath.Join(path, hashstr[:2], hashstr[2:4], hashstr)
	err := os.MkdirAll(filepath.Dir(p), 0755)
	if err != nil {
		return fmt.Errorf("createTextureFile: %w", err)
	}
	f, err := os.Stat(p)
	if err != nil && !errors.Is(err, os.ErrNotExist) {
		return fmt.Errorf("createTextureFile: %w", err)
	}
	if f == nil {
		err := os.WriteFile(p, b, 0644)
		if err != nil {
			return fmt.Errorf("createTextureFile: %w", err)
		}
	}
	return nil
}