/*
 * Copyright (C) 2024 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

use aconfigd_protos::ProtoStorageReturnMessage;
use aconfigd_rust::aconfigd::Aconfigd;
use aconfigd_system::Aconfigd as CXXAconfigd;
use anyhow::{anyhow, bail, Result};
use log::{debug, error, info};
use std::io::{Read, Write};
use std::os::fd::AsRawFd;
use std::os::unix::net::UnixListener;
use std::path::Path;

const ACONFIGD_SOCKET: &str = "aconfigd_system";
const ACONFIGD_ROOT_DIR: &str = "/metadata/aconfig";
const STORAGE_RECORDS: &str = "/metadata/aconfig/storage_records.pb";
const PLATFORM_STORAGE_RECORDS: &str = "/metadata/aconfig/platform_storage_records.pb";
const ACONFIGD_SOCKET_BACKLOG: i32 = 8;

/// start aconfigd socket service
pub fn start_socket() -> Result<()> {
    let fd = rustutils::sockets::android_get_control_socket(ACONFIGD_SOCKET)?;

    // SAFETY: Safe because this doesn't modify any memory and we check the return value.
    let ret = unsafe { libc::listen(fd.as_raw_fd(), ACONFIGD_SOCKET_BACKLOG) };
    if ret < 0 {
        bail!(std::io::Error::last_os_error());
    }

    let listener = UnixListener::from(fd);

    let storage_records = if aconfig_new_storage_flags::enable_aconfigd_from_mainline() {
        PLATFORM_STORAGE_RECORDS
    } else {
        STORAGE_RECORDS
    };

    if aconfig_new_storage_flags::enable_full_rust_system_aconfigd() {
        let mut aconfigd = Aconfigd::new(Path::new(ACONFIGD_ROOT_DIR), Path::new(storage_records));
        aconfigd.initialize_from_storage_record()?;

        debug!("start waiting for a new client connection through socket.");
        for stream in listener.incoming() {
            match stream {
                Ok(mut stream) => {
                    if let Err(errmsg) = aconfigd.handle_socket_request_from_stream(&mut stream) {
                        error!("failed to handle socket request: {:?}", errmsg);
                    }
                }
                Err(errmsg) => {
                    error!("failed to listen for an incoming message: {:?}", errmsg);
                }
            }
        }
    } else {
        let aconfigd = CXXAconfigd::new(ACONFIGD_ROOT_DIR, storage_records);
        aconfigd
            .initialize_in_memory_storage_records()
            .map_err(|e| anyhow!("failed to init memory storage records: {e}"))?;

        debug!("start waiting for a new client connection through socket.");
        for stream in listener.incoming() {
            match stream {
                Ok(mut stream) => {
                    let mut length_buffer = [0u8; 4];
                    stream.read_exact(&mut length_buffer)?;
                    let message_length = u32::from_be_bytes(length_buffer);

                    let mut message_buffer = vec![0u8; message_length as usize];
                    stream.read_exact(&mut message_buffer)?;

                    match aconfigd.handle_socket_request(&message_buffer) {
                        Ok(response_buffer) => {
                            let mut response_length_buffer: [u8; 4] = [0; 4];
                            let response_size = &response_buffer.len();
                            response_length_buffer[0] = (response_size >> 24) as u8;
                            response_length_buffer[1] = (response_size >> 16) as u8;
                            response_length_buffer[2] = (response_size >> 8) as u8;
                            response_length_buffer[3] = *response_size as u8;
                            stream.write_all(&response_length_buffer)?;
                            stream.write_all(&response_buffer)?;
                        }
                        Err(e) => {
                            error!("failed to process socket request: {e}");
                        }
                    };
                }
                Err(errmsg) => {
                    error!("failed to listen for an incoming message: {:?}", errmsg);
                }
            }
        }
    }

    Ok(())
}

/// initialize mainline module storage files
pub fn mainline_init() -> Result<()> {
    if aconfig_new_storage_flags::enable_full_rust_system_aconfigd() {
        let mut aconfigd = Aconfigd::new(Path::new(ACONFIGD_ROOT_DIR), Path::new(STORAGE_RECORDS));
        aconfigd.initialize_from_storage_record()?;
        Ok(aconfigd.initialize_mainline_storage()?)
    } else {
        CXXAconfigd::new(ACONFIGD_ROOT_DIR, STORAGE_RECORDS)
            .initialize_mainline_storage()
            .map_err(|e| anyhow!("failed to init mainline storage: {e}"))
    }
}

/// initialize platform storage files
pub fn platform_init() -> Result<()> {
    let storage_records = if aconfig_new_storage_flags::enable_aconfigd_from_mainline() {
        PLATFORM_STORAGE_RECORDS
    } else {
        STORAGE_RECORDS
    };

    if aconfig_new_storage_flags::enable_full_rust_system_aconfigd() {
        let mut aconfigd = Aconfigd::new(Path::new(ACONFIGD_ROOT_DIR), Path::new(storage_records));
        aconfigd.remove_boot_files()?;
        aconfigd.initialize_from_storage_record()?;
        Ok(aconfigd.initialize_platform_storage()?)
    } else {
        CXXAconfigd::new(ACONFIGD_ROOT_DIR, storage_records)
            .initialize_platform_storage()
            .map_err(|e| anyhow!("failed to init platform storage: {e}"))
    }
}