using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using Luticate2.Utils.Dbo;
using Microsoft.EntityFrameworkCore;

namespace Luticate2.Utils.DataAccess
{
    public abstract class LuEfCrudDataAccess<TModel, TDboCreate, TDboRead, TDboUpdate, TDbContext> :
            LuEfDataAccess<TModel, TDbContext>
        where TModel : class
        where TDboCreate : class
        where TDboRead : class
        where TDboUpdate : class
        where TDbContext : DbContext
    {
        protected LuEfCrudDataAccess(TDbContext db, DbSet<TModel> table) : base(db, table)
        {
        }

        protected abstract TModel GetModelFromTCreate(TDboCreate obj);

        protected abstract TModel GetModelFromTUpdate(TDboUpdate obj);

        protected abstract TDboRead GetDboFromModel(TModel model);

        public LuResult<T> Add<T>(IEnumerable<TDboCreate> objs, Func<IEnumerable<TDboRead>, T> returnFunc)
        {
            return Execute(() =>
            {
                var models = objs.Select(GetModelFromTCreate).ToList();
                Table.AddRange(models);
                Db.SaveChanges();
                var dbos = models.Select(GetDboFromModel).ToList();
                var res = returnFunc(dbos);
                return LuResult<T>.Ok(res);
            });
        }

        public LuResult<T> Add<T>(TDboCreate obj, Func<TDboRead, T> returnFunc)
        {
            return Add(new List<TDboCreate> {obj}, list => returnFunc(list.First()));
        }

        public LuResult<IEnumerable<string>> AddGuid(IEnumerable<TDboCreate> objs)
        {
            var param = Expression.Parameter(typeof(TDboRead), "x");
            var exp = Expression.Property(param, "Id");
            var lambda = Expression.Lambda<Func<TDboRead, string>>(exp, param);
            var func = lambda.Compile();
            return Add(objs, list => list.Select(func));
        }

        public LuResult<string> AddGuid(TDboCreate obj)
        {
            return AddGuid(new List<TDboCreate> {obj}).To(list => list.First());
        }

        public LuResult<IEnumerable<long>> AddId(IEnumerable<TDboCreate> obj)
        {
            var param = Expression.Parameter(typeof(TDboRead), "x");
            var exp = Expression.Property(param, "Id");
            var lambda = Expression.Lambda<Func<TDboRead, long>>(exp, param);
            var func = lambda.Compile();
            return Add(obj, list => list.Select(func));
        }

        public LuResult<long> AddId(TDboCreate obj)
        {
            return AddId(new List<TDboCreate> {obj}).To(list => list.First());
        }

        public LuResult<IEnumerable<TDboRead>> AddDbo(IEnumerable<TDboCreate> obj)
        {
            return Add(obj, read => read);
        }

        public LuResult<TDboRead> AddDbo(TDboCreate obj)
        {
            return AddDbo(new List<TDboCreate> {obj}).To(list => list.First());
        }

        public LuResult<TDboRead> GetSingle(Expression<Func<TModel, bool>> predicate)
        {
            return Execute(() =>
            {
                var model = Table.FirstOrDefault(predicate);
                if (model == null)
                {
                    return LuResult<TDboRead>.Error(LuStatus.NotFound, typeof(TModel).Name + ": Value not found", "");
                }
                var dbo = GetDboFromModel(model);
                return LuResult<TDboRead>.Ok(dbo);
            });
        }

        public LuResult<TDboRead> GetSingleByKeys(params KeyValuePair<string, object>[] keys)
        {
            return GetSingle(GetExpression(keys));
        }

        public LuResult<TDboRead> GetSingleById(Guid id)
        {
            return GetSingleByKeys(new KeyValuePair<string, object>("id", id));
        }

        public LuResult<TDboRead> GetSingleById(string id)
        {
            return GetSingleById(new Guid(id));
        }

        public LuResult<TDboRead> GetSingleById(long id)
        {
            return GetSingleByKeys(new KeyValuePair<string, object>("id", id));
        }

        public LuResult<LuPaginatedDbo<TDboRead>> GetMultiple<TKey>(Func<IQueryable<TModel>> orderBy,
            Expression<Func<TModel, bool>> predicate, int page = 0, int perPage = int.MaxValue,
            params Expression<Func<TModel, TKey>>[] otherOrderBy)
        {
            return Execute(() =>
            {
                var count = Table.Count(predicate);
                var ordered = orderBy();
                var data = ordered.Where(predicate).Skip(page * perPage).Take(perPage).Select(GetDboFromModel).ToList();
                var result = new LuPaginatedDbo<TDboRead>
                {
                    Count = count,
                    Data = data
                };
                return LuResult<LuPaginatedDbo<TDboRead>>.Ok(result);
            });
        }

        public LuResult<LuPaginatedDbo<TDboRead>> GetMultiple<TKey>(Expression<Func<TModel, TKey>> orderBy,
            Expression<Func<TModel, bool>> predicate, int page = 0, int perPage = int.MaxValue)
        {
            return GetMultiple<TKey>(() => Table.OrderBy(orderBy), predicate, page, perPage);
        }

        public LuResult<LuPaginatedDbo<TDboRead>> GetMultiple<TKey>(Expression<Func<TModel, TKey>> orderBy,
            int page = 0, int perPage = int.MaxValue)
        {
            return GetMultiple(orderBy, x => true, page, perPage);
        }

        public LuResult<T> Edit<T>(Expression<Func<TModel, bool>> predicate, Action<TModel> update,
            Func<List<TDboRead>, T> returnFunc)
        {
            return Execute(() =>
            {
                var models = Table.Where(predicate);
                var editedDbos = new List<TDboRead>();
                foreach (var model in models)
                {
                    update(model);
                    editedDbos.Add(GetDboFromModel(model));
                    Db.Entry(model).State = EntityState.Modified;
                }
                Db.SaveChanges();
                var res = returnFunc(editedDbos);
                return LuResult<T>.Ok(res);
            });
        }

        public LuResult<T> EditSingleByPkId<T, TId>(TId id, Action<TModel> update, Func<TDboRead, T> returnFunc)
        {
            return Edit(GetExpression(new KeyValuePair<string, object>("id", id)), update,
                list => list.Count == 0 ? returnFunc(default(TDboRead)) : returnFunc(list[0]));
        }

        public LuResult<T> EditSingleById<T>(long id, Action<TModel> update, Func<TDboRead, T> returnFunc)
        {
            return EditSingleByPkId(id, update, returnFunc);
        }

        public LuResult<T> EditSingleById<T>(Guid id, Action<TModel> update, Func<TDboRead, T> returnFunc)
        {
            return EditSingleByPkId(id, update, returnFunc);
        }

        public LuResult<T> EditSingleById<T>(string id, Action<TModel> update, Func<TDboRead, T> returnFunc)
        {
            return EditSingleById(new Guid(id), update, returnFunc);
        }
    }
}