#[macro_use]
extern crate log;
extern crate regex;
extern crate tempfile;
extern crate walkdir;

pub mod adb;
pub mod shell;

#[cfg(test)]
pub mod test;

use std::collections::BTreeMap;
use std::convert::TryFrom;
use std::fmt;
use std::fs::File;
use std::io::{self, Read, Write};
use std::iter::FromIterator;
use std::net::TcpStream;
use std::num::{ParseIntError, TryFromIntError};
use std::path::Path;
use std::str::Utf8Error;
use std::time::{Duration, SystemTime};
use walkdir::WalkDir;

use crate::adb::{DeviceSerial, SyncCommand};

pub type Result<T> = std::result::Result<T, DeviceError>;

#[derive(Debug)]
pub enum DeviceError {
    Adb(String),
    Io(io::Error),
    FromInt(TryFromIntError),
    MultipleDevices,
    ParseInt(ParseIntError),
    UnknownDevice(String),
    Utf8(Utf8Error),
    WalkDir(walkdir::Error),
}

impl fmt::Display for DeviceError {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match *self {
            DeviceError::Adb(ref message) => message.fmt(f),
            DeviceError::MultipleDevices => write!(f, "Multiple Android devices online"),
            DeviceError::UnknownDevice(ref serial) => {
                write!(f, "Unknown Android device with serial '{}'", serial)
            }
            _ => self.to_string().fmt(f),
        }
    }
}

impl From<io::Error> for DeviceError {
    fn from(value: io::Error) -> DeviceError {
        DeviceError::Io(value)
    }
}

impl From<ParseIntError> for DeviceError {
    fn from(value: ParseIntError) -> DeviceError {
        DeviceError::ParseInt(value)
    }
}

impl From<TryFromIntError> for DeviceError {
    fn from(value: TryFromIntError) -> DeviceError {
        DeviceError::FromInt(value)
    }
}

impl From<Utf8Error> for DeviceError {
    fn from(value: Utf8Error) -> DeviceError {
        DeviceError::Utf8(value)
    }
}

impl From<walkdir::Error> for DeviceError {
    fn from(value: walkdir::Error) -> DeviceError {
        DeviceError::WalkDir(value)
    }
}

fn encode_message(payload: &str) -> Result<String> {
    let hex_length = u16::try_from(payload.len()).map(|len| format!("{:0>4X}", len))?;

    Ok(format!("{}{}", hex_length, payload).to_owned())
}

fn parse_device_info(line: &str) -> Option<DeviceInfo> {
    // Turn "serial\tdevice key1:value1 key2:value2 ..." into a `DeviceInfo`.
    let mut pairs = line.split_whitespace();
    let serial = pairs.next();
    let state = pairs.next();
    if let (Some(serial), Some("device")) = (serial, state) {
        let info: BTreeMap<String, String> = pairs
            .filter_map(|pair| {
                let mut kv = pair.split(':');
                if let (Some(k), Some(v), None) = (kv.next(), kv.next(), kv.next()) {
                    Some((k.to_owned(), v.to_owned()))
                } else {
                    None
                }
            })
            .collect();

        Some(DeviceInfo {
            serial: serial.to_owned(),
            info,
        })
    } else {
        None
    }
}

/// Reads the payload length of a host message from the stream.
fn read_length<R: Read>(stream: &mut R) -> Result<usize> {
    let mut bytes: [u8; 4] = [0; 4];
    stream.read_exact(&mut bytes)?;

    let response = std::str::from_utf8(&bytes)?;

    Ok(usize::from_str_radix(&response, 16)?)
}

/// Reads the payload length of a device message from the stream.
fn read_length_little_endian(reader: &mut dyn Read) -> Result<usize> {
    let mut bytes: [u8; 4] = [0; 4];
    reader.read_exact(&mut bytes)?;

    let n: usize = (bytes[0] as usize)
        + ((bytes[1] as usize) << 8)
        + ((bytes[2] as usize) << 16)
        + ((bytes[3] as usize) << 24);

    Ok(n)
}

/// Writes the payload length of a device message to the stream.
fn write_length_little_endian(writer: &mut dyn Write, n: usize) -> Result<usize> {
    let mut bytes = [0; 4];
    bytes[0] = (n & 0xFF) as u8;
    bytes[1] = ((n >> 8) & 0xFF) as u8;
    bytes[2] = ((n >> 16) & 0xFF) as u8;
    bytes[3] = ((n >> 24) & 0xFF) as u8;

    writer.write(&bytes[..]).map_err(DeviceError::Io)
}

fn read_response(stream: &mut TcpStream, has_output: bool, has_length: bool) -> Result<Vec<u8>> {
    let mut bytes: [u8; 1024] = [0; 1024];

    stream.read_exact(&mut bytes[0..4])?;

    if &bytes[0..4] != SyncCommand::Okay.code() {
        let n = bytes.len().min(read_length(stream)?);
        stream.read_exact(&mut bytes[0..n])?;

        let message = std::str::from_utf8(&bytes[0..n]).map(|s| format!("adb error: {}", s))?;

        return Err(DeviceError::Adb(message));
    }

    let mut response = Vec::new();

    if has_output {
        stream.read_to_end(&mut response)?;

        if response.len() >= 4 && &response[0..4] == SyncCommand::Okay.code() {
            // Sometimes the server produces OKAYOKAY.  Sometimes there is a transport OKAY and
            // then the underlying command OKAY.  This is straight from `chromedriver`.
            response = response.split_off(4);
        }

        if response.len() >= 4 && &response[0..4] == SyncCommand::Fail.code() {
            // The server may even produce OKAYFAIL, which means the underlying
            // command failed. First split-off the `FAIL` and length of the message.
            response = response.split_off(8);

            let message = std::str::from_utf8(&*response).map(|s| format!("adb error: {}", s))?;

            return Err(DeviceError::Adb(message));
        }

        if has_length {
            if response.len() >= 4 {
                let message = response.split_off(4);
                let slice: &mut &[u8] = &mut &*response;

                let n = read_length(slice)?;
                warn!(
                    "adb server response contained hexstring length {} and message length was {} \
                     and message was {:?}",
                    n,
                    message.len(),
                    std::str::from_utf8(&message)?
                );

                return Ok(message);
            } else {
                return Err(DeviceError::Adb(format!(
                    "adb server response did not contain expected hexstring length: {:?}",
                    std::str::from_utf8(&response)?
                )));
            }
        }
    }

    Ok(response)
}

/// Detailed information about an ADB device.
#[derive(Debug, Eq, PartialEq, Ord, PartialOrd)]
pub struct DeviceInfo {
    pub serial: DeviceSerial,
    pub info: BTreeMap<String, String>,
}

/// Represents a connection to an ADB host, which multiplexes the connections to
/// individual devices.
#[derive(Debug)]
pub struct Host {
    /// The TCP host to connect to.  Defaults to `"localhost"`.
    pub host: Option<String>,
    /// The TCP port to connect to.  Defaults to `5037`.
    pub port: Option<u16>,
    /// Optional TCP read timeout duration.  Defaults to 2s.
    pub read_timeout: Option<Duration>,
    /// Optional TCP write timeout duration.  Defaults to 2s.
    pub write_timeout: Option<Duration>,
}

impl Default for Host {
    fn default() -> Host {
        Host {
            host: Some("localhost".to_string()),
            port: Some(5037),
            read_timeout: Some(Duration::from_secs(2)),
            write_timeout: Some(Duration::from_secs(2)),
        }
    }
}

impl Host {
    /// Searches for available devices, and selects the one as specified by `device_serial`.
    ///
    /// If multiple devices are online, and no device has been specified,
    /// the `ANDROID_SERIAL` environment variable can be used to select one.
    pub fn device_or_default<T: AsRef<str>>(self, device_serial: Option<&T>) -> Result<Device> {
        let serials: Vec<String> = self
            .devices::<Vec<_>>()?
            .into_iter()
            .map(|d| d.serial)
            .collect();

        if let Some(ref serial) = device_serial
            .map(|v| v.as_ref().to_owned())
            .or_else(|| std::env::var("ANDROID_SERIAL").ok())
        {
            if !serials.contains(serial) {
                return Err(DeviceError::UnknownDevice(serial.clone()));
            }

            return Ok(Device {
                host: self,
                serial: serial.to_owned(),
            });
        }

        if serials.len() > 1 {
            return Err(DeviceError::MultipleDevices);
        }

        if let Some(ref serial) = serials.first() {
            return Ok(Device {
                host: self,
                serial: serial.to_string(),
            });
        }

        Err(DeviceError::Adb("No Android devices are online".to_owned()))
    }

    pub fn connect(&self) -> Result<TcpStream> {
        let stream = TcpStream::connect(format!(
            "{}:{}",
            self.host.clone().unwrap_or_else(|| "localhost".to_owned()),
            self.port.unwrap_or(5037)
        ))?;
        stream.set_read_timeout(self.read_timeout)?;
        stream.set_write_timeout(self.write_timeout)?;
        Ok(stream)
    }

    pub fn execute_command(
        &self,
        command: &str,
        has_output: bool,
        has_length: bool,
    ) -> Result<String> {
        let mut stream = self.connect()?;

        stream.write_all(encode_message(command)?.as_bytes())?;
        let bytes = read_response(&mut stream, has_output, has_length)?;
        // TODO: should we assert no bytes were read?

        let response = std::str::from_utf8(&bytes)?;

        Ok(response.to_owned())
    }

    pub fn execute_host_command(
        &self,
        host_command: &str,
        has_length: bool,
        has_output: bool,
    ) -> Result<String> {
        self.execute_command(&format!("host:{}", host_command), has_output, has_length)
    }

    pub fn features<B: FromIterator<String>>(&self) -> Result<B> {
        let features = self.execute_host_command("features", true, true)?;
        Ok(features.split(',').map(|x| x.to_owned()).collect())
    }

    pub fn devices<B: FromIterator<DeviceInfo>>(&self) -> Result<B> {
        let response = self.execute_host_command("devices-l", true, true)?;

        let infos: B = response.lines().filter_map(parse_device_info).collect();

        Ok(infos)
    }
}

/// Represents an ADB device.
#[derive(Debug)]
pub struct Device {
    /// ADB host that controls this device.
    pub host: Host,

    /// Serial number uniquely identifying this ADB device.
    pub serial: DeviceSerial,
}

impl Device {
    pub fn execute_host_command(
        &self,
        command: &str,
        has_output: bool,
        has_length: bool,
    ) -> Result<String> {
        let mut stream = self.host.connect()?;

        let switch_command = format!("host:transport:{}", self.serial);
        debug!("execute_host_command: >> {:?}", &switch_command);
        stream.write_all(encode_message(&switch_command)?.as_bytes())?;
        let _bytes = read_response(&mut stream, false, false)?;
        debug!("execute_host_command: << {:?}", _bytes);
        // TODO: should we assert no bytes were read?

        debug!("execute_host_command: >> {:?}", &command);
        stream.write_all(encode_message(&command)?.as_bytes())?;
        let bytes = read_response(&mut stream, has_output, has_length)?;

        let response = std::str::from_utf8(&bytes)?;
        debug!("execute_host_command: << {:?}", response);

        Ok(response.to_owned())
    }

    pub fn execute_host_shell_command(&self, shell_command: &str) -> Result<String> {
        let response =
            self.execute_host_command(&format!("shell:{}", shell_command), true, false)?;

        Ok(response)
    }

    pub fn is_app_installed(&self, package: &str) -> Result<bool> {
        self.execute_host_shell_command(&format!("pm path {}", package))
            .map(|v| v.contains("package:"))
    }

    pub fn clear_app_data(&self, package: &str) -> Result<bool> {
        self.execute_host_shell_command(&format!("pm clear {}", package))
            .map(|v| v.contains("Success"))
    }

    pub fn launch<T: AsRef<str>>(
        &self,
        package: &str,
        activity: &str,
        am_start_args: &[T],
    ) -> Result<bool> {
        let mut am_start = format!("am start -W -n {}/{}", package, activity);

        for arg in am_start_args {
            am_start.push_str(" ");
            am_start.push_str(&shell::escape(arg.as_ref()));
        }

        self.execute_host_shell_command(&am_start)
            .map(|v| v.contains("Complete"))
    }

    pub fn force_stop(&self, package: &str) -> Result<()> {
        debug!("Force stopping Android package: {}", package);
        self.execute_host_shell_command(&format!("am force-stop {}", package))
            .and(Ok(()))
    }

    pub fn forward_port(&self, local: u16, remote: u16) -> Result<u16> {
        let command = format!(
            "host-serial:{}:forward:tcp:{};tcp:{}",
            self.serial, local, remote
        );
        let response = self.host.execute_command(&command, true, false)?;

        if local == 0 {
            Ok(response.parse::<u16>()?)
        } else {
            Ok(local)
        }
    }

    pub fn kill_forward_port(&self, local: u16) -> Result<()> {
        let command = format!("killforward:tcp:{}", local);
        self.execute_host_command(&command, true, false).and(Ok(()))
    }

    pub fn kill_forward_all_ports(&self) -> Result<()> {
        self.execute_host_command(&"killforward-all".to_owned(), false, false)
            .and(Ok(()))
    }

    pub fn reverse_port(&self, remote: u16, local: u16) -> Result<u16> {
        let command = format!("reverse:forward:tcp:{};tcp:{}", remote, local);
        let response = self.execute_host_command(&command, true, false)?;

        if remote == 0 {
            Ok(response.parse::<u16>()?)
        } else {
            Ok(remote)
        }
    }

    pub fn kill_reverse_port(&self, remote: u16) -> Result<()> {
        let command = format!("reverse:killforward:tcp:{}", remote);
        self.execute_host_command(&command, true, true).and(Ok(()))
    }

    pub fn kill_reverse_all_ports(&self) -> Result<()> {
        let command = "reverse:killforward-all".to_owned();
        self.execute_host_command(&command, false, false)
            .and(Ok(()))
    }

    pub fn push(&self, buffer: &mut dyn Read, dest: &Path, mode: u32) -> Result<()> {
        // Implement the ADB protocol to send a file to the device.
        // The protocol consists of the following steps:
        // * Send "host:transport" command with device serial
        // * Send "sync:" command to initialize file transfer
        // * Send "SEND" command with name and mode of the file
        // * Send "DATA" command one or more times for the file content
        // * Send "DONE" command to indicate end of file transfer
        let mut stream = self.host.connect()?;

        let message = encode_message(&format!("host:transport:{}", self.serial))?;
        stream.write_all(message.as_bytes())?;
        let _bytes = read_response(&mut stream, false, true)?;

        let message = encode_message("sync:")?;
        stream.write_all(message.as_bytes())?;
        let _bytes = read_response(&mut stream, false, true)?;

        stream.write_all(SyncCommand::Send.code())?;
        let args_ = format!("{},{}", dest.display(), mode);
        let args = args_.as_bytes();
        write_length_little_endian(&mut stream, args.len())?;
        stream.write_all(args)?;

        // Use a 32KB buffer to transfer the file contents
        // TODO: Maybe adjust to maxdata (256KB)
        let mut buf = [0; 32 * 1024];

        loop {
            let len = buffer.read(&mut buf)?;

            if len == 0 {
                break;
            }

            stream.write_all(SyncCommand::Data.code())?;
            write_length_little_endian(&mut stream, len)?;
            stream.write_all(&buf[0..len])?;
        }

        // https://android.googlesource.com/platform/system/core/+/master/adb/SYNC.TXT#66
        //
        // When the file is transferred a sync request "DONE" is sent, where length is set
        // to the last modified time for the file. The server responds to this last
        // request (but not to chunk requests) with an "OKAY" sync response (length can
        // be ignored).
        let time: u32 = ((SystemTime::now().duration_since(SystemTime::UNIX_EPOCH))
            .unwrap()
            .as_secs()
            & 0xFFFF_FFFF) as u32;

        stream.write_all(SyncCommand::Done.code())?;
        write_length_little_endian(&mut stream, time as usize)?;

        // Status.
        stream.read_exact(&mut buf[0..4])?;

        if &buf[0..4] == SyncCommand::Okay.code() {
            Ok(())
        } else if &buf[0..4] == SyncCommand::Fail.code() {
            let n = buf.len().min(read_length_little_endian(&mut stream)?);

            stream.read_exact(&mut buf[0..n])?;

            let message = std::str::from_utf8(&buf[0..n])
                .map(|s| format!("adb error: {}", s))
                .unwrap_or_else(|_| "adb error was not utf-8".into());

            Err(DeviceError::Adb(message))
        } else {
            Err(DeviceError::Adb("FAIL (unknown)".to_owned()))
        }
    }

    pub fn push_dir(&self, source: &Path, dest_dir: &Path, mode: u32) -> Result<()> {
        let walker = WalkDir::new(source).follow_links(false).into_iter();

        for entry in walker {
            let entry = entry?;
            let path = entry.path();

            if !entry.metadata()?.is_file() {
                continue;
            }

            let mut file = File::open(path)?;

            let mut dest = dest_dir.to_path_buf();
            dest.push(
                path.strip_prefix(source)
                    .map_err(|e| io::Error::new(io::ErrorKind::Other, e.to_string()))?,
            );

            self.push(&mut file, &dest, mode)?;
        }

        Ok(())
    }
}