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PetAdoptionMarta.sol

//SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;

contract PetAdoption {
    
    Adoption[16] public adoptions;
    
    mapping(uint256 => Pet) private pet_list;
    
    struct Adoption {
        address owner;
        uint256 date;
    }
    
    enum Breed {Labrador_Retriever, German_Shepherd_Dog, Golden_Retriever, French_Bulldog, Bulldog, Other}
    
    struct Pet {
        Breed breed;
        bool pet_exists;
    }
    
    event Adopted(address _adopter, uint256 _petId);
    
    //Function to give an abandoned pet to the shelter, indicating id and breed. 
    //The id cannot be assigned to another pet. 
    function giveToShelter(uint256 _petId, Breed _breed) public {
        require(pet_list[_petId].pet_exists == false);
        require(_petId >= 0 && _petId <=15);
        pet_list[_petId].breed = _breed;
        pet_list[_petId].pet_exists = true;
    }
    
    //Function to see the breed of a pet introducing its id
    function seePet(uint256 _petId) public view returns (string memory){
        //function to choose _petId according to the breed of the dog
        require(pet_list[_petId].pet_exists == true);
        return getMyEnumKeyByValue(pet_list[_petId].breed);
    }
    
    //Function to adopt a pet that has to be in the pet_list previously given with giveToShelter.
    function adopt(uint256 _petId) public {
        require(_petId >= 0 && _petId <=15);
        require(adoptions[_petId].owner == address(0x0));
        require(pet_list[_petId].pet_exists == true);
        adoptions[_petId].owner = msg.sender;
        adoptions[_petId].date = now;
        
        emit Adopted(msg.sender, _petId);
    }
    
    //Function to return to Shelter a previously adopted pet.
    function returnToShelter(uint256 _petId) public {
        require(adoptions[_petId].owner == msg.sender);
        require(now > adoptions[_petId].date + 0.1 minutes);
        require(pet_list[_petId].pet_exists == true);
        adoptions[_petId].owner = address(0x0);
        adoptions[_petId].date = 0;
    }
    
    //Aux function to translate the enum of the Breed on seePet
    function getMyEnumKeyByValue (Breed _breed) private view returns (string memory) {
        if (Breed.Labrador_Retriever == _breed) return "Labrador_Retriever";
        if (Breed.German_Shepherd_Dog == _breed) return "German_Shepherd_Dog";
        if (Breed.Golden_Retriever == _breed) return "Golden_Retriever";
        if (Breed.French_Bulldog == _breed) return "French_Bulldog";
        if (Breed.Bulldog == _breed) return "Bulldog";
        
        return "Wrong Index";
    }

    
}