// 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.IO;
using System.Threading.Tasks;
using Kyoo.Abstractions.Controllers;
using Kyoo.Abstractions.Models;
using Kyoo.Abstractions.Models.Attributes;
using Kyoo.Abstractions.Models.Exceptions;
using Kyoo.Abstractions.Models.Permissions;
using Kyoo.Abstractions.Models.Utils;
using Kyoo.Authentication.Attributes;
using Kyoo.Authentication.Models;
using Kyoo.Authentication.Models.DTO;
using Kyoo.Models;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.IdentityModel.Tokens;
using static Kyoo.Abstractions.Models.Utils.Constants;
using BCryptNet = BCrypt.Net.BCrypt;

namespace Kyoo.Authentication.Views;

/// <summary>
/// Sign in, Sign up or refresh tokens.
/// </summary>
[ApiController]
[Route("auth")]
[ApiDefinition("Authentication", Group = UsersGroup)]
public class AuthApi(
	IUserRepository users,
	OidcController oidc,
	ITokenController tokenController,
	IThumbnailsManager thumbs,
	PermissionOption options
) : ControllerBase
{
	/// <summary>
	/// Create a new Forbidden result from an object.
	/// </summary>
	/// <param name="value">The json value to output on the response.</param>
	/// <returns>A new forbidden result with the given json object.</returns>
	public static ObjectResult Forbid(object value)
	{
		return new ObjectResult(value) { StatusCode = StatusCodes.Status403Forbidden };
	}

	private static string _BuildUrl(string baseUrl, Dictionary<string, string?> queryParams)
	{
		char querySep = baseUrl.Contains('?') ? '&' : '?';
		foreach ((string key, string? val) in queryParams)
		{
			if (val is null)
				continue;
			baseUrl += $"{querySep}{key}={val}";
			querySep = '&';
		}
		return baseUrl;
	}

	/// <summary>
	/// Oauth Login.
	/// </summary>
	/// <remarks>
	/// Login via a registered oauth provider.
	/// </remarks>
	/// <param name="provider">The provider code.</param>
	/// <param name="redirectUrl">
	/// A url where you will be redirected with the query params provider, code and error. It can be a deep link.
	/// </param>
	/// <returns>A redirect to the provider's login page.</returns>
	/// <response code="404">The provider is not register with this instance of kyoo.</response>
	[HttpGet("login/{provider}")]
	[ProducesResponseType(StatusCodes.Status302Found)]
	[ProducesResponseType(StatusCodes.Status404NotFound, Type = typeof(RequestError))]
	public ActionResult<JwtToken> LoginVia(string provider, [FromQuery] string redirectUrl)
	{
		if (!options.OIDC.ContainsKey(provider) || !options.OIDC[provider].Enabled)
		{
			return NotFound(
				new RequestError(
					$"Invalid provider. {provider} is not registered no this instance of kyoo."
				)
			);
		}
		OidcProvider prov = options.OIDC[provider];
		return Redirect(
			_BuildUrl(
				prov.AuthorizationUrl,
				new()
				{
					["response_type"] = "code",
					["client_id"] = prov.ClientId,
					["redirect_uri"] =
						$"{options.PublicUrl.TrimEnd('/')}/api/auth/logged/{provider}",
					["scope"] = prov.Scope,
					["state"] = redirectUrl,
				}
			)
		);
	}

	/// <summary>
	/// Oauth Code Redirect.
	/// </summary>
	/// <remarks>
	/// This route is not meant to be called manually, the user should be redirected automatically here
	/// after a successful login on the /login/{provider} page.
	/// </remarks>
	/// <returns>A redirect to the provider's login page.</returns>
	/// <response code="403">The provider gave an error.</response>
	[HttpGet("logged/{provider}")]
	[ProducesResponseType(StatusCodes.Status302Found)]
	public ActionResult OauthCodeRedirect(string provider, string code, string state, string? error)
	{
		return Redirect(
			_BuildUrl(
				state,
				new()
				{
					["provider"] = provider,
					["code"] = code,
					["error"] = error,
				}
			)
		);
	}

	/// <summary>
	/// Oauth callback
	/// </summary>
	/// <remarks>
	/// This route should be manually called by the page that got redirected to after a call to /login/{provider}.
	/// </remarks>
	/// <returns>A jwt token</returns>
	/// <response code="400">Bad provider or code</response>
	[HttpPost("callback/{provider}")]
	[ProducesResponseType(StatusCodes.Status200OK)]
	[ProducesResponseType(StatusCodes.Status400BadRequest, Type = typeof(RequestError))]
	public async Task<ActionResult<JwtToken>> OauthCallback(string provider, string code)
	{
		if (!options.OIDC.ContainsKey(provider) || !options.OIDC[provider].Enabled)
		{
			return NotFound(
				new RequestError(
					$"Invalid provider. {provider} is not registered no this instance of kyoo."
				)
			);
		}
		if (code == null)
			return BadRequest(new RequestError("Invalid code."));

		Guid? userId = User.GetId();
		User user = userId.HasValue
			? await oidc.LinkAccountOrLogin(userId.Value, provider, code)
			: await oidc.LoginViaCode(provider, code);
		return new JwtToken(
			tokenController.CreateAccessToken(user, out TimeSpan expireIn),
			await tokenController.CreateRefreshToken(user),
			expireIn
		);
	}

	/// <summary>
	/// Unlink account
	/// </summary>
	/// <remarks>
	/// Unlink your account from an external account.
	/// </remarks>
	/// <param name="provider">The provider code.</param>
	/// <returns>Your updated user account</returns>
	[HttpDelete("login/{provider}")]
	[ProducesResponseType(StatusCodes.Status200OK)]
	[UserOnly]
	public Task<User> UnlinkAccount(string provider)
	{
		Guid id = User.GetIdOrThrow();
		return users.DeleteExternalToken(id, provider);
	}

	/// <summary>
	/// Login.
	/// </summary>
	/// <remarks>
	/// Login as a user and retrieve an access and a refresh token.
	/// </remarks>
	/// <param name="request">The body of the request.</param>
	/// <returns>A new access and a refresh token.</returns>
	/// <response code="403">The user and password does not match.</response>
	[HttpPost("login")]
	[ProducesResponseType(StatusCodes.Status200OK)]
	[ProducesResponseType(StatusCodes.Status403Forbidden, Type = typeof(RequestError))]
	[DisableOnEnvVar("AUTHENTICATION_DISABLE_PASSWORD_LOGIN")]
	public async Task<ActionResult<JwtToken>> Login([FromBody] LoginRequest request)
	{
		User? user = await users.GetOrDefault(
			new Filter<User>.Eq(nameof(Abstractions.Models.User.Username), request.Username)
		);
		if (user != null && user.Password == null)
			return Forbid(
				new RequestError(
					"This account was registerd via oidc. Please login via oidc or add a password to your account in the settings first"
				)
			);
		if (user == null || !BCryptNet.Verify(request.Password, user.Password))
			return Forbid(new RequestError("The user and password does not match."));

		return new JwtToken(
			tokenController.CreateAccessToken(user, out TimeSpan expireIn),
			await tokenController.CreateRefreshToken(user),
			expireIn
		);
	}

	/// <summary>
	/// Register.
	/// </summary>
	/// <remarks>
	/// Register a new user and get a new access/refresh token for this new user.
	/// </remarks>
	/// <param name="request">The body of the request.</param>
	/// <returns>A new access and a refresh token.</returns>
	/// <response code="400">The request is invalid.</response>
	/// <response code="409">A user already exists with this username or email address.</response>
	[HttpPost("register")]
	[ProducesResponseType(StatusCodes.Status200OK)]
	[ProducesResponseType(StatusCodes.Status400BadRequest, Type = typeof(RequestError))]
	[ProducesResponseType(StatusCodes.Status409Conflict, Type = typeof(RequestError))]
	[DisableOnEnvVar("AUTHENTICATION_DISABLE_USER_REGISTRATION")]
	public async Task<ActionResult<JwtToken>> Register([FromBody] RegisterRequest request)
	{
		try
		{
			User user = await users.Create(request.ToUser());
			return new JwtToken(
				tokenController.CreateAccessToken(user, out TimeSpan expireIn),
				await tokenController.CreateRefreshToken(user),
				expireIn
			);
		}
		catch (DuplicatedItemException)
		{
			return Conflict(new RequestError("A user already exists with this username."));
		}
	}

	/// <summary>
	/// Refresh a token.
	/// </summary>
	/// <remarks>
	/// Refresh an access token using the given refresh token. A new access and refresh token are generated.
	/// </remarks>
	/// <param name="token">A valid refresh token.</param>
	/// <returns>A new access and refresh token.</returns>
	/// <response code="403">The given refresh token is invalid.</response>
	[HttpGet("refresh")]
	[ProducesResponseType(StatusCodes.Status200OK)]
	[ProducesResponseType(StatusCodes.Status403Forbidden, Type = typeof(RequestError))]
	public async Task<ActionResult<JwtToken>> Refresh([FromQuery] string token)
	{
		try
		{
			Guid userId = tokenController.GetRefreshTokenUserID(token);
			User user = await users.Get(userId);
			return new JwtToken(
				tokenController.CreateAccessToken(user, out TimeSpan expireIn),
				await tokenController.CreateRefreshToken(user),
				expireIn
			);
		}
		catch (ItemNotFoundException)
		{
			return Forbid(new RequestError("Invalid refresh token."));
		}
		catch (SecurityTokenException ex)
		{
			return Forbid(new RequestError(ex.Message));
		}
	}

	/// <summary>
	/// Reset your password
	/// </summary>
	/// <remarks>
	/// Change your password.
	/// </remarks>
	/// <param name="request">The old and new password</param>
	/// <returns>Your account info.</returns>
	/// <response code="403">The old password is invalid.</response>
	[HttpPost("password-reset")]
	[UserOnly]
	[ProducesResponseType(StatusCodes.Status200OK)]
	[ProducesResponseType(StatusCodes.Status403Forbidden, Type = typeof(RequestError))]
	public async Task<ActionResult<User>> ResetPassword([FromBody] PasswordResetRequest request)
	{
		User user = await users.Get(User.GetIdOrThrow());
		if (user.HasPassword && !BCryptNet.Verify(request.OldPassword, user.Password))
			return Forbid(new RequestError("The old password is invalid."));
		return await users.Patch(
			user.Id,
			(user) =>
			{
				user.Password = BCryptNet.HashPassword(request.NewPassword);
				return user;
			}
		);
	}

	/// <summary>
	/// Get authenticated user.
	/// </summary>
	/// <remarks>
	/// Get information about the currently authenticated user. This can also be used to ensure that you are
	/// logged in.
	/// </remarks>
	/// <returns>The currently authenticated user.</returns>
	/// <response code="401">The user is not authenticated.</response>
	/// <response code="403">The given access token is invalid.</response>
	[HttpGet("me")]
	[UserOnly]
	[ProducesResponseType(StatusCodes.Status200OK)]
	[ProducesResponseType(StatusCodes.Status401Unauthorized, Type = typeof(RequestError))]
	[ProducesResponseType(StatusCodes.Status403Forbidden, Type = typeof(RequestError))]
	public async Task<ActionResult<User>> GetMe()
	{
		try
		{
			return await users.Get(User.GetIdOrThrow());
		}
		catch (ItemNotFoundException)
		{
			return Forbid(new RequestError("Invalid token"));
		}
	}

	/// <summary>
	/// Edit self
	/// </summary>
	/// <remarks>
	/// Edit information about the currently authenticated user.
	/// </remarks>
	/// <param name="user">The new data for the current user.</param>
	/// <returns>The currently authenticated user after modifications.</returns>
	/// <response code="401">The user is not authenticated.</response>
	/// <response code="403">The given access token is invalid.</response>
	[HttpPut("me")]
	[UserOnly]
	[ProducesResponseType(StatusCodes.Status200OK)]
	[ProducesResponseType(StatusCodes.Status401Unauthorized, Type = typeof(RequestError))]
	[ProducesResponseType(StatusCodes.Status403Forbidden, Type = typeof(RequestError))]
	public async Task<ActionResult<User>> EditMe(User user)
	{
		try
		{
			user.Id = User.GetIdOrThrow();
			return await users.Edit(user);
		}
		catch (ItemNotFoundException)
		{
			return Forbid(new RequestError("Invalid token"));
		}
	}

	/// <summary>
	/// Patch self
	/// </summary>
	/// <remarks>
	/// Edit only provided informations about the currently authenticated user.
	/// </remarks>
	/// <param name="patch">The new data for the current user.</param>
	/// <returns>The currently authenticated user after modifications.</returns>
	/// <response code="401">The user is not authenticated.</response>
	/// <response code="403">The given access token is invalid.</response>
	[HttpPatch("me")]
	[UserOnly]
	[ProducesResponseType(StatusCodes.Status200OK)]
	[ProducesResponseType(StatusCodes.Status401Unauthorized, Type = typeof(RequestError))]
	[ProducesResponseType(StatusCodes.Status403Forbidden, Type = typeof(RequestError))]
	public async Task<ActionResult<User>> PatchMe([FromBody] Patch<User> patch)
	{
		Guid userId = User.GetIdOrThrow();
		try
		{
			if (patch.Id.HasValue && patch.Id != userId)
				throw new ArgumentException("Can't edit your user id.");
			if (patch.ContainsKey(nameof(Abstractions.Models.User.Password)))
				throw new ArgumentException(
					"Can't edit your password via a PATCH. Use /auth/password-reset"
				);
			return await users.Patch(userId, patch.Apply);
		}
		catch (ItemNotFoundException)
		{
			return Forbid(new RequestError("Invalid token"));
		}
	}

	/// <summary>
	/// Delete account
	/// </summary>
	/// <remarks>
	/// Delete the current account.
	/// </remarks>
	/// <response code="401">The user is not authenticated.</response>
	/// <response code="403">The given access token is invalid.</response>
	[HttpDelete("me")]
	[UserOnly]
	[ProducesResponseType(StatusCodes.Status204NoContent)]
	[ProducesResponseType(StatusCodes.Status401Unauthorized, Type = typeof(RequestError))]
	[ProducesResponseType(StatusCodes.Status403Forbidden, Type = typeof(RequestError))]
	public async Task<ActionResult<User>> DeleteMe()
	{
		try
		{
			await users.Delete(User.GetIdOrThrow());
			return NoContent();
		}
		catch (ItemNotFoundException)
		{
			return Forbid(new RequestError("Invalid token"));
		}
	}

	/// <summary>
	/// Get profile picture
	/// </summary>
	/// <remarks>
	/// Get your profile picture
	/// </remarks>
	/// <response code="401">The user is not authenticated.</response>
	/// <response code="403">The given access token is invalid.</response>
	[HttpGet("me/logo")]
	[UserOnly]
	[ProducesResponseType(StatusCodes.Status200OK)]
	[ProducesResponseType(StatusCodes.Status401Unauthorized, Type = typeof(RequestError))]
	[ProducesResponseType(StatusCodes.Status403Forbidden, Type = typeof(RequestError))]
	public async Task<ActionResult> GetProfilePicture()
	{
		Stream img = await thumbs.GetUserImage(User.GetIdOrThrow());
		// Allow clients to cache the image for 6 month.
		Response.Headers.CacheControl = $"public, max-age={60 * 60 * 24 * 31 * 6}";
		return File(img, "image/webp", true);
	}

	/// <summary>
	/// Set profile picture
	/// </summary>
	/// <remarks>
	/// Set your profile picture
	/// </remarks>
	/// <response code="401">The user is not authenticated.</response>
	/// <response code="403">The given access token is invalid.</response>
	[HttpPost("me/logo")]
	[UserOnly]
	[ProducesResponseType(StatusCodes.Status204NoContent)]
	[ProducesResponseType(StatusCodes.Status401Unauthorized, Type = typeof(RequestError))]
	[ProducesResponseType(StatusCodes.Status403Forbidden, Type = typeof(RequestError))]
	public async Task<ActionResult> SetProfilePicture(IFormFile picture)
	{
		if (picture == null || picture.Length == 0)
			return BadRequest();
		await thumbs.SetUserImage(User.GetIdOrThrow(), picture.OpenReadStream());
		return NoContent();
	}

	/// <summary>
	/// Delete profile picture
	/// </summary>
	/// <remarks>
	/// Delete your profile picture
	/// </remarks>
	/// <response code="401">The user is not authenticated.</response>
	/// <response code="403">The given access token is invalid.</response>
	[HttpDelete("me/logo")]
	[UserOnly]
	[ProducesResponseType(StatusCodes.Status204NoContent)]
	[ProducesResponseType(StatusCodes.Status401Unauthorized, Type = typeof(RequestError))]
	[ProducesResponseType(StatusCodes.Status403Forbidden, Type = typeof(RequestError))]
	public async Task<ActionResult> DeleteProfilePicture()
	{
		await thumbs.SetUserImage(User.GetIdOrThrow(), null);
		return NoContent();
	}
}