using InnovEnergy.App.Backend.Database;
using InnovEnergy.App.Backend.DataTypes;
using InnovEnergy.App.Backend.DataTypes.Methods;
using InnovEnergy.App.Backend.Relations;
using InnovEnergy.Lib.Utils;
using Microsoft.AspNetCore.Mvc;

namespace InnovEnergy.App.Backend.Controllers;

[ApiController]
[Route("api/")]
public class Controller : ControllerBase  
{
    [HttpPost(nameof(Login))]
    public ActionResult<Session> Login(Credentials credentials)
    {
        var session = credentials.Login();

        return session is null 
             ? Unauthorized() 
             : session;
    }


    [HttpPost(nameof(Logout))]
    public ActionResult Logout()
    {
        var session = GetSession();

        return session.Logout()
             ? Ok()
             : Unauthorized();
    }
    

    [HttpGet(nameof(GetUserById))]
    public ActionResult<User> GetUserById(Int64 id)
    {
        var caller = GetSession()?.User;
        if (caller == null)
            return Unauthorized();
    
        var user = Db.GetUserById(id);
    
        if (user is null || !caller.HasAccessTo(user))
            return Unauthorized();

        user.Password = "";
        return user;
    }

    
    [HttpGet(nameof(GetInstallationById))]
    public ActionResult<Installation> GetInstallationById(Int64 id)
    {
        var user = GetSession()?.User;
        if (user == null)
            return Unauthorized();
    
        var installation = Db.GetInstallationById(id);
    
        if (installation is null || !user.HasAccessTo(installation))
            return Unauthorized();
    
        return installation;
    }
    
    [HttpGet(nameof(GetUsersWithAccessToInstallation))]
    public ActionResult<IEnumerable<Object>> GetUsersWithAccessToInstallation(Int64 id)
    {
        var user = GetSession()?.User;
        if (user == null)
            return Unauthorized();
    
        var installation = Db.GetInstallationById(id);
        
        if (installation is null || !user.HasAccessTo(installation))
            return Unauthorized();

        var directAccess = installation
                          .UsersWithDirectAccess()
                          .Where(u => u.IsDescendantOf(user));

        var inheritedAccess = installation
                             .Ancestors()
                             .SelectMany(f => f.UsersWithDirectAccess()
                                               .Where(u => u.IsDescendantOf(user))
                                               .Select(u => new { folderId = f.Id, user = u }));
        
        return directAccess
              .Concat<Object>(inheritedAccess)
              .Apply(Ok);  // TODO: typing
    }
    
    [HttpGet(nameof(GetUsersWithAccessToFolder))]
    public ActionResult<IEnumerable<Object>> GetUsersWithAccessToFolder(Int64 id)
    {
        var user = GetSession()?.User;
        if (user == null)
            return Unauthorized();
    
        var folder = Db.GetFolderById(id);
        
        if (folder is null || !user.HasAccessTo(folder))
            return Unauthorized();

        return folder
              .Ancestors()
              .Prepend(folder)
              .SelectMany(f => f.UsersWithDirectAccess()
                                .Where(u => u.IsDescendantOf(user))
                                .Select(u => new { folderId = f.Id, user = u }))
              .ToList();
    }
    
    [HttpGet(nameof(GetFolderById))]
    public ActionResult<Folder> GetFolderById(Int64 id)
    {
        var user = GetSession()?.User;
        if (user == null)
            return Unauthorized();
        
        var folder = Db.GetFolderById(id);
    
        if (folder is null || !user.HasAccessTo(folder))
            return Unauthorized();
    
        return folder;
    }
    
    
    [HttpGet(nameof(GetAllInstallations))]
    public ActionResult<IEnumerable<Installation>> GetAllInstallations()
    {
        var user = GetSession()?.User;

        if (user is null)
            return Unauthorized();
        
        return user.AccessibleInstallations().ToList();
    }
    
    

    [HttpGet(nameof(GetAllFolders))]
    public ActionResult<IEnumerable<Folder>> GetAllFolders()
    {
        var user = GetSession()?.User;

        if (user is null)
            return Unauthorized();
        
        return new(user.AccessibleFolders());
    }
    
    
    [HttpGet(nameof(GetAllFoldersAndInstallations))]
    public ActionResult<IEnumerable<TreeNode>> GetAllFoldersAndInstallations()
    {
        var user = GetSession()?.User;

        if (user is null)
            return Unauthorized();
        
        return new (user.AccessibleFoldersAndInstallations());
    }
    

    [HttpPost(nameof(CreateUser))]
    public ActionResult<User> CreateUser(User newUser)
    {
        return GetSession().Create(newUser) 
             ? newUser 
             : Unauthorized() ;
    }
    
    [HttpPost(nameof(CreateInstallation))]
    public async Task<ActionResult<Installation>> CreateInstallation(Installation installation)
    {
        if (!await GetSession().Create(installation))
            return Unauthorized();
        
        return installation;
    }
    
    [HttpPost(nameof(CreateFolder))]
    public ActionResult<Folder> CreateFolder(Folder folder)
    {
        var session = GetSession();

        if (!session.Create(folder))
            return Unauthorized();
        
        return folder;
    }
    
    [HttpPost(nameof(GrantUserAccessToFolder))]
    public ActionResult GrantUserAccessToFolder(FolderAccess folderAccess)
    {
        var session = GetSession();

        // TODO: automatic BadRequest when properties are null during deserialization
        var folder = Db.GetFolderById(folderAccess.FolderId);
        var user   = Db.GetUserById(folderAccess.UserId);

        return session.GrantUserAccessTo(user, folder) 
            ? Ok()
            : Unauthorized();
    }
    
    
    [HttpPost(nameof(RevokeUserAccessToFolder))]
    public ActionResult RevokeUserAccessToFolder(FolderAccess folderAccess)
    {
        var session = GetSession();

        // TODO: automatic BadRequest when properties are null during deserialization
        var folder = Db.GetFolderById(folderAccess.FolderId);
        var user   = Db.GetUserById(folderAccess.UserId);

        return session.RevokeUserAccessTo(user, folder) 
             ? Ok()
             : Unauthorized();
    }
    
    
    [HttpPost(nameof(GrantUserAccessToInstallation))]
    public ActionResult GrantUserAccessToInstallation(InstallationAccess installationAccess)
    {
        var session = GetSession();
       
        // TODO: automatic BadRequest when properties are null during deserialization
        var installation = Db.GetFolderById(installationAccess.InstallationId);
        var user         = Db.GetUserById(installationAccess.UserId);
        
        return session.GrantUserAccessTo(user, installation) 
            ? Ok()
            : Unauthorized();
    }
    
    [HttpPost(nameof(RevokeUserAccessToInstallation))]
    public ActionResult RevokeUserAccessToInstallation(InstallationAccess installationAccess)
    {
        var session = GetSession();
       
        // TODO: automatic BadRequest when properties are null during deserialization
        var installation = Db.GetFolderById(installationAccess.InstallationId);
        var user         = Db.GetUserById(installationAccess.UserId);
        
        return session.RevokeUserAccessTo(user, installation) 
             ? Ok()
             : Unauthorized();
    }
    
    
    
    [HttpPut(nameof(UpdateUser))]
    public ActionResult<User> UpdateUser(User updatedUser)
    {
        var session = GetSession();

        if (!session.Update(updatedUser)) 
            return Unauthorized();
        
        updatedUser.Password = ""; // TODO: generic sanitize return values 
        
        return updatedUser;
    }
    
    
    [HttpPut(nameof(UpdateInstallation))]
    public ActionResult<Installation> UpdateInstallation(Installation installation)
    {
        var session = GetSession();

        if (!session.Update(installation))
            return Unauthorized();
        
        return installation;
    }
    
    
    [HttpPut(nameof(UpdateFolder))]
    public ActionResult<Folder> UpdateFolder(Folder folder)
    {
        var session = GetSession();

        if (!session.Update(folder))
            return Unauthorized();
        
        return folder;
    }
    
    [HttpDelete(nameof(DeleteUser))]
    public ActionResult DeleteUser(Int64 userId)
    {
        var session = GetSession();
        var user    = Db.GetUserById(userId);

        return session.Delete(user) 
             ? Ok()
             : Unauthorized();
    }
    
    [HttpDelete(nameof(DeleteInstallation))]
    public ActionResult DeleteInstallation(Int64 installationId)
    {
        var session      = GetSession();
        var installation = Db.GetInstallationById(installationId);

        return session.Delete(installation)
             ? Ok()  
             : Unauthorized();
    }

    [HttpDelete(nameof(DeleteFolder))]
    public ActionResult DeleteFolder(Int64 folderId)
    {
        var session = GetSession();

        var folder = Db.GetFolderById(folderId);

        return session.Delete(folder) 
             ? Ok() 
             : Unauthorized();
        
    }

    private static Session? GetSession()
    {
        var ctxAccessor = new HttpContextAccessor();
        return ctxAccessor.HttpContext?.Items["Session"] as Session;
    }
}