using System;
using System.Collections.Generic;
using System.Linq;
using FluentValidation;
using InternshipSystem.Core.ValueObject;

namespace InternshipSystem.Core.Entity.Internship
{
    public class Internship
    {
        public long Id { get; set; }
        public Student Student { get; set; }
        public InternshipRegistration InternshipRegistration { get; set; }
        public Report Report { get; set; }
        public List<Document> Documentation { get; set; }
        public Edition Edition { get; set; }
        
        public float? Grade { get; set; }

        public static Internship CreateStudentsInternship(Student student)
        {
            var internship = new Internship();

            internship.Student = student;

            internship.InternshipRegistration = InternshipRegistration.Create();
            internship.Report = Report.Create();
            internship.Documentation = new List<Document>();

            if (student.Semester != 6)
            {
                internship.AddNewDocument("", DocumentType.OutsideSemesterApproval);
            }
            
            return internship;
        }

        public void AddNewDocument(string description, DocumentType type)
        {
            if (type != DocumentType.Other && Documentation.Any(d => d.Type == type))
            {
                return;
            }
            
            var document = new Document
            {
                Description = description,
                Type = type,
                State = DocumentState.Draft
            };
            
            Documentation.Add(document);
        }

        public void RemoveDocument(DocumentType documentType)
        {
            if (documentType == DocumentType.Other)
            {
                return;
            }
            
            var doc = Documentation.FirstOrDefault(d => d.Type == documentType);

            if (doc != null)
            { 
                Documentation.Remove(doc);
            }
        }

        public void RemoveDocument(long id)
        {
            var doc = Documentation.FirstOrDefault(d => d.Id == id);

            if (doc != null)
            { 
                Documentation.Remove(doc);
            }
        }

        public IEnumerable<ErrorDescription> ValidateStatus()
        {
            var validator = new Validator();

            var result = validator.Validate(this);

            return result.ToErrorDescription();
        }

        private class Validator : AbstractValidator<Internship>
        {
            public Validator()
            {
                RuleFor(i => i.Report)
                    .Must(r => r.State == DocumentState.Accepted)
                    .WithMessage("error.report.not_accepted");
                RuleFor(i => i.InternshipRegistration)
                    .Must(r => r.State == DocumentState.Accepted)
                    .WithMessage("error.registration.not_accepted");
                RuleForEach(i => i.Documentation)
                    .Must(d => d.State == DocumentState.Accepted)
                    .WithMessage("error.documentation.not_accepted");
            }
        }
    }
}