// Kyoo - A portable and vast media library solution.
// Copyright (c) Kyoo.
//
// See AUTHORS.md and LICENSE file in the project root for full license information.
//
// Kyoo 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
// any later version.
//
// Kyoo 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 Kyoo. If not, see <https://www.gnu.org/licenses/>.

using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using Kyoo.Abstractions.Controllers;
using Kyoo.Abstractions.Models;
using Kyoo.Abstractions.Models.Permissions;
using Kyoo.Abstractions.Models.Utils;
using Kyoo.Models;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;

namespace Kyoo.Core.Api;

/// <summary>
/// A base class to handle CRUD operations on a specific resource type <typeparamref name="T"/>.
/// </summary>
/// <typeparam name="T">The type of resource to make CRUD apis for.</typeparam>
[ApiController]
public class CrudApi<T> : BaseApi
	where T : class, IResource, IQuery
{
	/// <summary>
	/// The repository of the resource, used to retrieve, save and do operations on the baking store.
	/// </summary>
	protected IRepository<T> Repository { get; }

	/// <summary>
	/// Create a new <see cref="CrudApi{T}"/> using the given repository and base url.
	/// </summary>
	/// <param name="repository">
	/// The repository to use as a baking store for the type <typeparamref name="T"/>.
	/// </param>
	public CrudApi(IRepository<T> repository)
	{
		Repository = repository;
	}

	/// <summary>
	/// Get item
	/// </summary>
	/// <remarks>
	/// Get a specific resource via it's ID or it's slug.
	/// </remarks>
	/// <param name="identifier">The ID or slug of the resource to retrieve.</param>
	/// <param name="fields">The aditional fields to include in the result.</param>
	/// <returns>The retrieved resource.</returns>
	/// <response code="404">A resource with the given ID or slug does not exist.</response>
	[HttpGet("{identifier:id}")]
	[PartialPermission(Kind.Read)]
	[ProducesResponseType(StatusCodes.Status200OK)]
	[ProducesResponseType(StatusCodes.Status404NotFound)]
	public async Task<ActionResult<T>> Get(Identifier identifier, [FromQuery] Include<T>? fields)
	{
		T? ret = await identifier.Match(
			id => Repository.GetOrDefault(id, fields),
			slug => Repository.GetOrDefault(slug, fields)
		);
		if (ret == null)
			return NotFound();
		return ret;
	}

	/// <summary>
	/// Get count
	/// </summary>
	/// <remarks>
	/// Get the number of resources that match the filters.
	/// </remarks>
	/// <param name="filter">A list of filters to respect.</param>
	/// <returns>How many resources matched that filter.</returns>
	/// <response code="400">Invalid filters.</response>
	[HttpGet("count")]
	[PartialPermission(Kind.Read)]
	[ProducesResponseType(StatusCodes.Status200OK)]
	[ProducesResponseType(StatusCodes.Status400BadRequest, Type = typeof(RequestError))]
	public async Task<ActionResult<int>> GetCount([FromQuery] Filter<T> filter)
	{
		return await Repository.GetCount(filter);
	}

	/// <summary>
	/// Get all
	/// </summary>
	/// <remarks>
	/// Get all resources that match the given filter.
	/// </remarks>
	/// <param name="sortBy">Sort information about the query (sort by, sort order).</param>
	/// <param name="filter">Filter the returned items.</param>
	/// <param name="pagination">How many items per page should be returned, where should the page start...</param>
	/// <param name="fields">The aditional fields to include in the result.</param>
	/// <returns>A list of resources that match every filters.</returns>
	/// <response code="400">Invalid filters or sort information.</response>
	[HttpGet]
	[PartialPermission(Kind.Read)]
	[ProducesResponseType(StatusCodes.Status200OK)]
	[ProducesResponseType(StatusCodes.Status400BadRequest, Type = typeof(RequestError))]
	public async Task<ActionResult<Page<T>>> GetAll(
		[FromQuery] Sort<T> sortBy,
		[FromQuery] Filter<T>? filter,
		[FromQuery] Pagination pagination,
		[FromQuery] Include<T>? fields
	)
	{
		ICollection<T> resources = await Repository.GetAll(filter, sortBy, fields, pagination);

		return Page(resources, pagination.Limit);
	}

	/// <summary>
	/// Create new
	/// </summary>
	/// <remarks>
	/// Create a new item and store it. You may leave the ID unspecified, it will be filed by Kyoo.
	/// </remarks>
	/// <param name="resource">The resource to create.</param>
	/// <returns>The created resource.</returns>
	/// <response code="400">The resource in the request body is invalid.</response>
	/// <response code="409">This item already exists (maybe a duplicated slug).</response>
	[HttpPost]
	[PartialPermission(Kind.Create)]
	[ProducesResponseType(StatusCodes.Status200OK)]
	[ProducesResponseType(StatusCodes.Status400BadRequest, Type = typeof(RequestError))]
	[ProducesResponseType(StatusCodes.Status409Conflict, Type = typeof(ActionResult<>))]
	public virtual async Task<ActionResult<T>> Create([FromBody] T resource)
	{
		return await Repository.Create(resource);
	}

	/// <summary>
	/// Edit
	/// </summary>
	/// <remarks>
	/// Edit an item. If the ID is specified it will be used to identify the resource.
	/// If not, the slug will be used to identify it.
	/// </remarks>
	/// <param name="resource">The resource to edit.</param>
	/// <returns>The edited resource.</returns>
	/// <response code="400">The resource in the request body is invalid.</response>
	/// <response code="404">No item found with the specified ID (or slug).</response>
	[HttpPut]
	[PartialPermission(Kind.Write)]
	[ProducesResponseType(StatusCodes.Status200OK)]
	[ProducesResponseType(StatusCodes.Status400BadRequest, Type = typeof(RequestError))]
	[ProducesResponseType(StatusCodes.Status404NotFound)]
	public async Task<ActionResult<T>> Edit([FromBody] T resource)
	{
		if (resource.Id != Guid.Empty)
			return await Repository.Edit(resource);

		T old = await Repository.Get(resource.Slug);
		resource.Id = old.Id;
		return await Repository.Edit(resource);
	}

	/// <summary>
	/// Patch
	/// </summary>
	/// <remarks>
	/// Edit only specified properties of an item. If the ID is specified it will be used to identify the resource.
	/// If not, the slug will be used to identify it.
	/// </remarks>
	/// <param name="patch">The resource to patch.</param>
	/// <returns>The edited resource.</returns>
	/// <response code="400">The resource in the request body is invalid.</response>
	/// <response code="404">No item found with the specified ID (or slug).</response>
	[HttpPatch]
	[PartialPermission(Kind.Write)]
	[ProducesResponseType(StatusCodes.Status200OK)]
	[ProducesResponseType(StatusCodes.Status400BadRequest, Type = typeof(RequestError))]
	[ProducesResponseType(StatusCodes.Status404NotFound)]
	public async Task<ActionResult<T>> Patch([FromBody] Patch<T> patch)
	{
		if (patch.Id.HasValue)
			return await Repository.Patch(patch.Id.Value, patch.Apply);
		if (patch.Slug == null)
			throw new ArgumentException(
				"Either the Id or the slug of the resource has to be defined to edit it."
			);

		T old = await Repository.Get(patch.Slug);
		return await Repository.Patch(old.Id, patch.Apply);
	}

	/// <summary>
	/// Patch
	/// </summary>
	/// <remarks>
	/// Edit only specified properties of an item. If the ID is specified it will be used to identify the resource.
	/// If not, the slug will be used to identify it.
	/// </remarks>
	/// <param name="identifier">The id or slug of the resource.</param>
	/// <param name="patch">The resource to patch.</param>
	/// <returns>The edited resource.</returns>
	/// <response code="400">The resource in the request body is invalid.</response>
	/// <response code="404">No item found with the specified ID (or slug).</response>
	[HttpPatch("{identifier:id}")]
	[PartialPermission(Kind.Write)]
	[ProducesResponseType(StatusCodes.Status200OK)]
	[ProducesResponseType(StatusCodes.Status400BadRequest, Type = typeof(RequestError))]
	[ProducesResponseType(StatusCodes.Status404NotFound)]
	public async Task<ActionResult<T>> Patch(Identifier identifier, [FromBody] Patch<T> patch)
	{
		Guid id = await identifier.Match(
			id => Task.FromResult(id),
			async slug => (await Repository.Get(slug)).Id
		);
		if (patch.Id.HasValue && patch.Id.Value != id)
			throw new ArgumentException("Can not edit id of a resource.");
		return await Repository.Patch(id, patch.Apply);
	}

	/// <summary>
	/// Delete an item
	/// </summary>
	/// <remarks>
	/// Delete one item via it's ID or it's slug.
	/// </remarks>
	/// <param name="identifier">The ID or slug of the resource to delete.</param>
	/// <returns>The item has successfully been deleted.</returns>
	/// <response code="404">No item could be found with the given id or slug.</response>
	[HttpDelete("{identifier:id}")]
	[PartialPermission(Kind.Delete)]
	[ProducesResponseType(StatusCodes.Status204NoContent)]
	[ProducesResponseType(StatusCodes.Status404NotFound)]
	public async Task<IActionResult> Delete(Identifier identifier)
	{
		await identifier.Match(id => Repository.Delete(id), slug => Repository.Delete(slug));
		return NoContent();
	}

	/// <summary>
	/// Delete all where
	/// </summary>
	/// <remarks>
	/// Delete all items matching the given filters. If no filter is specified, delete all items.
	/// </remarks>
	/// <param name="filter">The list of filters.</param>
	/// <returns>The item(s) has successfully been deleted.</returns>
	/// <response code="400">One or multiple filters are invalid.</response>
	[HttpDelete]
	[PartialPermission(Kind.Delete)]
	[ProducesResponseType(StatusCodes.Status204NoContent)]
	[ProducesResponseType(StatusCodes.Status400BadRequest, Type = typeof(RequestError))]
	public async Task<IActionResult> Delete([FromQuery] Filter<T> filter)
	{
		if (filter == null)
			return BadRequest(
				new RequestError("Incule a filter to delete items, all items won't be deleted.")
			);

		await Repository.DeleteAll(filter);
		return NoContent();
	}
}