use anyhow::{Context, Result};
use common::proto::komp_ac::auth::{
    AddRoleRequest, AssignUserRoleRequest, AuthResponse, AuthorizationSnapshot,
    ChangePasswordRequest, GetAuthorizationRequest, GrantPermissionRequest,
    GrantableObject, ListGrantableObjectsRequest, ListRolePermissionsRequest, ListRolesRequest,
    ListUsersRequest, LoginRequest, LoginResponse, LogoutRequest, PasswordOperationResponse,
    RegisterRequest, RemoveRoleRequest, ResetUserPasswordRequest, RevokePermissionRequest,
    RevokeUserSessionsRequest, Role, RolePermissions, UserSummary,
    auth_service_client::AuthServiceClient,
};
use tonic::transport::Channel;
use tonic::Request;

use crate::transport::{DEFAULT_GRPC_ENDPOINT, authenticated_request, connect_channel};

pub fn validate_password_change(password: &str, confirmation: &str) -> Result<()> {
    if password.is_empty() {
        anyhow::bail!("Password is required");
    }
    if password != confirmation {
        anyhow::bail!("Passwords do not match");
    }
    if password.len() < 8 {
        anyhow::bail!("Password must be at least 8 characters");
    }
    Ok(())
}

pub fn validate_optional_password(password: Option<&str>, confirmation: Option<&str>) -> Result<()> {
    let password = password.unwrap_or_default();
    let confirmation = confirmation.unwrap_or_default();
    if password.is_empty() && confirmation.is_empty() {
        return Ok(());
    }
    validate_password_change(password, confirmation)
}

#[derive(Clone)]
pub struct AuthClient {
    client: AuthServiceClient<Channel>,
}

impl AuthClient {
    pub async fn new() -> Result<Self> {
        let endpoint = std::env::var("GRPC_ENDPOINT")
            .unwrap_or_else(|_| DEFAULT_GRPC_ENDPOINT.to_string());
        Self::connect(&endpoint).await
    }

    pub async fn connect(endpoint: &str) -> Result<Self> {
        Self::with_channel(connect_channel(endpoint).await?).await
    }

    pub async fn with_channel(channel: Channel) -> Result<Self> {
        Ok(Self {
            client: AuthServiceClient::new(channel),
        })
    }

    pub async fn login(&mut self, identifier: String, password: String) -> Result<LoginResponse> {
        Ok(self
            .client
            .login(Request::new(LoginRequest {
                identifier,
                password,
            }))
            .await?
            .into_inner())
    }

    pub async fn register(
        &mut self,
        username: String,
        email: String,
        password: Option<String>,
        password_confirmation: Option<String>,
        timezone: String,
        phone_country: String,
    ) -> Result<AuthResponse> {
        validate_optional_password(password.as_deref(), password_confirmation.as_deref())?;
        Ok(self
            .client
            .register(Request::new(RegisterRequest {
                username,
                email,
                password: password.unwrap_or_default(),
                password_confirmation: password_confirmation.unwrap_or_default(),
                timezone,
                phone_country,
            }))
            .await?
            .into_inner())
    }

    pub async fn change_password(
        &mut self,
        token: &str,
        current_password: String,
        new_password: String,
        new_password_confirmation: String,
    ) -> Result<PasswordOperationResponse> {
        validate_password_change(&new_password, &new_password_confirmation)?;
        let request = authenticated_request(
            Some(token),
            ChangePasswordRequest {
                current_password,
                new_password,
                new_password_confirmation,
            },
        )?;
        Ok(self.client.change_password(request).await?.into_inner())
    }

    pub async fn logout(&mut self, token: &str) -> Result<()> {
        self.client
            .logout(authenticated_request(Some(token), LogoutRequest {})?)
            .await?;
        Ok(())
    }

    pub async fn get_authorization(&mut self, token: &str) -> Result<AuthorizationSnapshot> {
        Ok(self
            .client
            .get_authorization(authenticated_request(Some(token), GetAuthorizationRequest {})?)
            .await?
            .into_inner())
    }

    pub async fn list_roles(&mut self, token: &str) -> Result<Vec<Role>> {
        Ok(self
            .client
            .list_roles(authenticated_request(Some(token), ListRolesRequest {})?)
            .await?
            .into_inner()
            .roles)
    }

    pub async fn add_role(&mut self, token: &str, name: String, parent: String) -> Result<()> {
        self.client
            .add_role(authenticated_request(
                Some(token),
                AddRoleRequest { name, parent },
            )?)
            .await?;
        Ok(())
    }

    pub async fn remove_role(&mut self, token: &str, name: String) -> Result<()> {
        self.client
            .remove_role(authenticated_request(Some(token), RemoveRoleRequest { name })?)
            .await?;
        Ok(())
    }

    pub async fn grant_permission(
        &mut self,
        token: &str,
        role: String,
        object: String,
        action: String,
    ) -> Result<()> {
        self.client
            .grant_permission(authenticated_request(
                Some(token),
                GrantPermissionRequest {
                    role,
                    object,
                    action,
                },
            )?)
            .await?;
        Ok(())
    }

    pub async fn revoke_permission(
        &mut self,
        token: &str,
        role: String,
        object: String,
        action: String,
    ) -> Result<()> {
        self.client
            .revoke_permission(authenticated_request(
                Some(token),
                RevokePermissionRequest {
                    role,
                    object,
                    action,
                },
            )?)
            .await?;
        Ok(())
    }

    pub async fn try_revoke_permission(
        &mut self,
        token: &str,
        role: String,
        object: String,
        action: String,
    ) -> Result<bool> {
        let request = authenticated_request(
            Some(token),
            RevokePermissionRequest {
                role,
                object,
                action,
            },
        )?;
        match self.client.revoke_permission(request).await {
            Ok(_) => Ok(true),
            Err(status) if status.code() == tonic::Code::NotFound => Ok(false),
            Err(status) => Err(status.into()),
        }
    }

    pub async fn list_role_permissions(
        &mut self,
        token: &str,
        role: String,
    ) -> Result<RolePermissions> {
        Ok(self
            .client
            .list_role_permissions(authenticated_request(
                Some(token),
                ListRolePermissionsRequest { role },
            )?)
            .await?
            .into_inner())
    }

    pub async fn list_grantable_objects(
        &mut self,
        token: &str,
        target_role: String,
    ) -> Result<Vec<GrantableObject>> {
        Ok(self
            .client
            .list_grantable_objects(authenticated_request(
                Some(token),
                ListGrantableObjectsRequest { target_role },
            )?)
            .await?
            .into_inner()
            .objects)
    }

    pub async fn assign_user_role(
        &mut self,
        token: &str,
        username: String,
        role: String,
    ) -> Result<()> {
        self.client
            .assign_user_role(authenticated_request(
                Some(token),
                AssignUserRoleRequest { username, role },
            )?)
            .await?;
        Ok(())
    }

    pub async fn list_users(&mut self, token: &str) -> Result<Vec<UserSummary>> {
        Ok(self
            .client
            .list_users(authenticated_request(Some(token), ListUsersRequest {})?)
            .await?
            .into_inner()
            .users)
    }

    pub async fn revoke_user_sessions(&mut self, token: &str, username: String) -> Result<()> {
        self.client
            .revoke_user_sessions(authenticated_request(
                Some(token),
                RevokeUserSessionsRequest { username },
            )?)
            .await?;
        Ok(())
    }

    pub async fn reset_user_password(
        &mut self,
        token: &str,
        username: String,
        new_password: String,
        new_password_confirmation: String,
    ) -> Result<PasswordOperationResponse> {
        validate_password_change(&new_password, &new_password_confirmation)?;
        Ok(self
            .client
            .reset_user_password(authenticated_request(
                Some(token),
                ResetUserPasswordRequest {
                    username,
                    new_password,
                    new_password_confirmation,
                },
            )?)
            .await
            .context("Failed to reset user password")?
            .into_inner())
    }
}