// Copyright (c) 2025 Nikolai Papin
//
// This file is part of Easywish
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
// the GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

package services

import (
	"context"
	minioclient "easywish/internal/minioClient"
	"easywish/internal/utils"
	"time"

	"github.com/google/uuid"
	"github.com/minio/minio-go/v7"
	"go.uber.org/zap"
)

type UploadService interface {
	GetAvatarUrl() (*string, *map[string]string, error)
	GetImageUrl() (*string, *map[string]string, error)
}

type uploadServiceImpl struct {
	minio *minio.Client
	log   *zap.Logger

	avatarPolicy minio.PostPolicy
	imagePolicy minio.PostPolicy
}

func NewUploadService(_minio *minio.Client, _log *zap.Logger) UploadService {
	service := uploadServiceImpl{
		minio: _minio,
		log:   _log,
	}

	avatarPolicy := minio.NewPostPolicy()
	imagePolicy := minio.NewPostPolicy()

	// At the moment the parameters match for both policies but this may
	// change with introduction of new policies
	for _, policy := range [...]*minio.PostPolicy{avatarPolicy, imagePolicy} {
		if err := policy.SetBucket(minioclient.Buckets["uploads"]); err != nil {
			panic("Failed to set bucket for policy: " + err.Error())
		}

		if err := policy.SetExpires(time.Now().UTC().Add(10 * time.Minute)); err != nil {
			panic("Failed to set expiration time for policy: " + err.Error())
		}

		if err := policy.SetContentTypeStartsWith("image/"); err != nil {
			panic("Failed to set allowed content types for the policy: " + err.Error())
		}

		if err := policy.SetContentLengthRange(1, 512*1024); err != nil {
			panic("Failed to set allowed content length range for the policy: " + err.Error())
		}
	}

	service.imagePolicy = *imagePolicy
	service.avatarPolicy = *avatarPolicy

	return &service
}

func (u *uploadServiceImpl) genUrl(policy minio.PostPolicy, prefix string) (*string, *map[string]string, error) {

	object := prefix + uuid.New().String()

	if err := policy.SetKey(object); err != nil {
		u.log.Error(
			"Failed to set random key for presigned url",
			zap.Error(err))
		return nil, nil, err
	}

	url, formData, err := u.minio.PresignedPostPolicy(context.Background(), &policy)
	if err != nil {
		u.log.Error(
			"Failed to generate presigned url",
			zap.String("object", object),
			zap.Error(err))
		return nil, nil, err
	}

	convertedUrl, err := utils.LocalizeS3Url(url.String()); if err != nil {
		u.log.Error(
			"Failed to localize object URL to user-accessible format",
			zap.String("url", url.String()),
			zap.Error(err))
		return nil, nil, err
	}

	return &convertedUrl, &formData, nil
}

func (u *uploadServiceImpl) GetAvatarUrl() (*string, *map[string]string, error) {
	return u.genUrl(u.avatarPolicy, "avatar-")
}

func (u *uploadServiceImpl) GetImageUrl() (*string, *map[string]string, error) {
	return u.genUrl(u.imagePolicy, "image-")
}