use ctrl_gfx::error::GfxError;
use ctrl_gfx::*;
use ctrl_rog_bios::CtrlRogBios;
use log::{error, info, warn};
use rog_types::gfx_vendors::GfxVendors;
use session_manager::{are_gfx_sessions_alive, get_sessions};
use std::{io::Write, ops::Add, path::Path};
use std::{iter::FromIterator, thread::JoinHandle};
use std::{process::Command, thread::sleep, time::Duration};
use std::{str::FromStr, sync::mpsc};
use std::{sync::Arc, sync::Mutex};
use sysfs_class::{PciDevice, SysClass};
use system::{GraphicsDevice, PciBus};
use zbus::dbus_interface;

use crate::*;

pub struct CtrlGraphics {
    bus: PciBus,
    _amd: Vec<GraphicsDevice>,
    _intel: Vec<GraphicsDevice>,
    nvidia: Vec<GraphicsDevice>,
    #[allow(dead_code)]
    other: Vec<GraphicsDevice>,
    config: Arc<Mutex<Config>>,
    thread_kill: Arc<Mutex<Option<mpsc::Sender<bool>>>>,
}

trait Dbus {
    fn vendor(&self) -> String;
    fn power(&self) -> String;
    fn set_vendor(&mut self, vendor: String);
    fn notify_gfx(&self, vendor: &str) -> zbus::Result<()>;
    fn notify_action(&self, action: &str) -> zbus::Result<()>;
}

use std::convert::TryInto;

#[dbus_interface(name = "org.asuslinux.Daemon")]
impl Dbus for CtrlGraphics {
    fn vendor(&self) -> String {
        self.get_gfx_mode()
            .map(|gfx| gfx.into())
            .unwrap_or_else(|err| format!("Get vendor failed: {}", err))
    }

    fn power(&self) -> String {
        Self::get_runtime_status().unwrap_or_else(|err| format!("Get power status failed: {}", err))
    }

    fn set_vendor(&mut self, vendor: String) {
        if let Ok(tmp) = GfxVendors::from_str(&vendor) {
            info!("GFX: Switching gfx mode to {}", vendor);
            let msg = self.set_gfx_config(tmp).unwrap_or_else(|err| {
                error!("GFX: {}", err);
                format!("Failed: {}", err.to_string())
            });
            self.notify_gfx(&vendor)
                .unwrap_or_else(|err| warn!("GFX: {}", err));
            self.notify_action(&msg)
                .unwrap_or_else(|err| warn!("GFX: {}", err));
        }
    }

    #[dbus_interface(signal)]
    fn notify_gfx(&self, vendor: &str) -> zbus::Result<()> {}

    #[dbus_interface(signal)]
    fn notify_action(&self, action: &str) -> zbus::Result<()> {}
}

impl ZbusAdd for CtrlGraphics {
    fn add_to_server(self, server: &mut zbus::ObjectServer) {
        server
            .at(
                &"/org/asuslinux/Gfx"
                    .try_into()
                    .expect("Couldn't add to zbus"),
                self,
            )
            .map_err(|err| {
                warn!("GFX: CtrlGraphics: add_to_server {}", err);
                err
            })
            .ok();
    }
}

impl Reloadable for CtrlGraphics {
    fn reload(&mut self) -> Result<(), RogError> {
        self.auto_power()?;
        info!("GFX: Reloaded gfx mode: {:?}", self.get_gfx_mode()?);
        Ok(())
    }
}

impl CtrlGraphics {
    pub fn new(config: Arc<Mutex<Config>>) -> std::io::Result<CtrlGraphics> {
        let bus = PciBus::new()?;

        info!("GFX: Rescanning PCI bus");
        bus.rescan()?;

        let devs = PciDevice::all()?;

        let functions = |parent: &PciDevice| -> Vec<PciDevice> {
            let mut functions = Vec::new();
            if let Some(parent_slot) = parent.id().split('.').next() {
                for func in devs.iter() {
                    if let Some(func_slot) = func.id().split('.').next() {
                        if func_slot == parent_slot {
                            info!("GFX: {}: Function for {}", func.id(), parent.id());
                            functions.push(func.clone());
                        }
                    }
                }
            }
            functions
        };

        let mut amd = Vec::new();
        let mut intel = Vec::new();
        let mut nvidia = Vec::new();
        let mut other = Vec::new();
        for dev in devs.iter() {
            let c = dev.class()?;
            if 0x03 == (c >> 16) & 0xFF {
                match dev.vendor()? {
                    0x1002 => {
                        info!("GFX: {}: AMD graphics", dev.id());
                        amd.push(GraphicsDevice::new(dev.id().to_owned(), functions(&dev)));
                    }
                    0x10DE => {
                        info!("GFX: {}: NVIDIA graphics", dev.id());
                        nvidia.push(GraphicsDevice::new(dev.id().to_owned(), functions(&dev)));
                    }
                    0x8086 => {
                        info!("GFX: {}: Intel graphics", dev.id());
                        intel.push(GraphicsDevice::new(dev.id().to_owned(), functions(&dev)));
                    }
                    vendor => {
                        info!("GFX: {}: Other({:X}) graphics", dev.id(), vendor);
                        other.push(GraphicsDevice::new(dev.id().to_owned(), functions(&dev)));
                    }
                }
            }
        }

        Ok(CtrlGraphics {
            bus,
            _amd: amd,
            _intel: intel,
            nvidia,
            other,
            config,
            thread_kill: Arc::new(Mutex::new(None)),
        })
    }

    pub fn bus(&self) -> PciBus {
        self.bus.clone()
    }

    pub fn devices(&self) -> Vec<GraphicsDevice> {
        self.nvidia.clone()
    }

    fn save_gfx_mode(vendor: GfxVendors, config: Arc<Mutex<Config>>) -> Result<(), RogError> {
        if let Ok(mut config) = config.lock() {
            config.gfx_mode = vendor.clone();
            config.write();
            return Ok(());
        }
        // TODO: Error here
        Ok(())
    }

    /// Associated method to get which vendor mode is set
    pub fn get_gfx_mode(&self) -> Result<GfxVendors, RogError> {
        if let Ok(config) = self.config.lock() {
            return Ok(config.gfx_mode.clone());
        }
        // TODO: Error here
        Ok(GfxVendors::Hybrid)
    }

    fn get_runtime_status() -> Result<String, RogError> {
        const PATH: &str = "/sys/bus/pci/devices/0000:01:00.0/power/runtime_status";
        let buf = std::fs::read_to_string(PATH).map_err(|err| RogError::Read(PATH.into(), err))?;
        Ok(buf)
    }

    fn toggle_fallback_service(vendor: GfxVendors) -> Result<(), RogError> {
        let action = if vendor == GfxVendors::Nvidia {
            info!("GFX: Enabling nvidia-fallback.service");
            "enable"
        } else {
            info!("GFX: Disabling nvidia-fallback.service");
            "disable"
        };

        let status = Command::new("systemctl")
            .arg(action)
            .arg("nvidia-fallback.service")
            .status()
            .map_err(|err| RogError::Command("systemctl".into(), err))?;

        if !status.success() {
            // Error is ignored in case this service is removed
            warn!(
                "systemctl: {} (ignore warning if service does not exist!)",
                status
            );
        }

        Ok(())
    }

    fn write_xorg_conf(vendor: GfxVendors) -> Result<(), RogError> {
        let text = if vendor == GfxVendors::Nvidia {
            [PRIMARY_GPU_BEGIN, PRIMARY_GPU_NVIDIA, PRIMARY_GPU_END].concat()
        } else {
            [PRIMARY_GPU_BEGIN, PRIMARY_GPU_END].concat()
        };

        if !Path::new(XORG_PATH).exists() {
            std::fs::create_dir(XORG_PATH).map_err(|err| RogError::Write(XORG_PATH.into(), err))?;
        }

        let file = XORG_PATH.to_string().add(XORG_FILE);
        info!("GFX: Writing {}", file);
        let mut file = std::fs::OpenOptions::new()
            .create(true)
            .truncate(true)
            .write(true)
            .open(&file)
            .map_err(|err| RogError::Write(file, err))?;

        file.write_all(&text)
            .and_then(|_| file.sync_all())
            .map_err(|err| RogError::Write(MODPROBE_PATH.into(), err))?;
        Ok(())
    }

    fn write_modprobe_conf() -> Result<(), RogError> {
        info!("GFX: Writing {}", MODPROBE_PATH);

        let mut file = std::fs::OpenOptions::new()
            .create(true)
            .truncate(true)
            .write(true)
            .open(MODPROBE_PATH)
            .map_err(|err| RogError::Path(MODPROBE_PATH.into(), err))?;

        file.write_all(MODPROBE_BASE)
            .and_then(|_| file.sync_all())
            .map_err(|err| RogError::Write(MODPROBE_PATH.into(), err))?;

        Ok(())
    }

    fn unbind_remove_nvidia(devices: &[GraphicsDevice]) -> Result<(), RogError> {
        // Unbind NVIDIA graphics devices and their functions
        let unbinds = devices.iter().map(|dev| dev.unbind());

        // Remove NVIDIA graphics devices and their functions
        let removes = devices.iter().map(|dev| dev.remove());

        Result::from_iter(unbinds.chain(removes))
            .map_err(|err| RogError::Command("device unbind error".into(), err))?;

        Ok(())
    }

    fn log_uses_of_nvidia() {
        // lsof /dev/nvidia*
        let mut cmd = Command::new("lsof");
        cmd.arg("/dev/nvidia*");

        match cmd.output() {
            Ok(output) => {
                if !output.status.success() {
                    error!(
                        "Failed to list uses of nvidia devices: {}",
                        String::from_utf8_lossy(&output.stderr)
                    );
                } else if output.status.success() {
                    warn!("GFX: {}", String::from_utf8_lossy(&output.stdout));
                }
            }
            Err(err) => error!("GFX: Failed to list uses of nvidia devices: {}", err),
        }
    }

    fn do_driver_action(driver: &str, action: &str) -> Result<(), RogError> {
        let mut cmd = Command::new(action);
        cmd.arg(driver);

        let mut count = 0;
        const MAX_TRIES: i32 = 6;
        loop {
            if count > MAX_TRIES {
                let msg = format!("{} {} failed for unknown reason", action, driver);
                error!("GFX: {}", msg);
                return Ok(()); //Err(RogError::Modprobe(msg));
            }

            let output = cmd
                .output()
                .map_err(|err| RogError::Command(format!("{:?}", cmd), err))?;
            if !output.status.success() {
                if output
                    .stderr
                    .ends_with("is not currently loaded\n".as_bytes())
                {
                    return Ok(());
                }
                if output.stderr.ends_with("Permission denied\n".as_bytes()) {
                    let msg = format!(
                        "{} {} failed: {:?}",
                        action,
                        driver,
                        String::from_utf8_lossy(&output.stderr)
                    );
                    warn!("GFX: {}", msg);
                    warn!("GFX: It may be safe to ignore the above error, run `lsmod |grep nvidia` to confirm modules loaded");
                    return Ok(());
                }
                if count >= MAX_TRIES {
                    let msg = format!(
                        "{} {} failed: {:?}",
                        action,
                        driver,
                        String::from_utf8_lossy(&output.stderr)
                    );
                    return Err(RogError::Modprobe(msg));
                }
            } else if output.status.success() {
                return Ok(());
            }

            count += 1;
            std::thread::sleep(std::time::Duration::from_millis(250));
        }
    }

    fn do_display_manager_action(action: &str) -> Result<(), RogError> {
        let mut cmd = Command::new("systemctl");
        cmd.arg(action);
        cmd.arg(DISPLAY_MANAGER);

        let status = cmd
            .status()
            .map_err(|err| RogError::Command(format!("{:?}", cmd), err))?;
        if !status.success() {
            let msg = format!(
                "systemctl {} {} failed: {:?}",
                action, DISPLAY_MANAGER, status
            );
            return Err(GfxError::DisplayManagerAction(msg, status).into());
        }
        Ok(())
    }

    fn wait_display_manager_state(state: &str) -> Result<(), RogError> {
        let mut cmd = Command::new("systemctl");
        cmd.arg("is-active");
        cmd.arg(DISPLAY_MANAGER);

        let mut count = 0;

        while count <= 5 {
            let output = cmd
                .output()
                .map_err(|err| RogError::Command(format!("{:?}", cmd), err))?;
            if output.stdout.starts_with(state.as_bytes()) {
                return Ok(());
            }
            std::thread::sleep(std::time::Duration::from_millis(500));
            count += 1;
        }
        return Err(GfxError::DisplayManagerTimeout(state.into()).into());
    }

    /// Write the config changes and add/remove drivers and devices depending
    /// on selected mode:
    ///
    /// Tasks:
    /// - write xorg config
    /// - write modprobe config
    /// - rescan for devices
    ///   + add drivers
    ///   + or remove drivers and devices
    pub fn do_vendor_tasks(
        vendor: GfxVendors,
        devices: &[GraphicsDevice],
        bus: &PciBus,
    ) -> Result<(), RogError> {
        Self::write_xorg_conf(vendor)?;
        Self::write_modprobe_conf()?; // TODO: Not required here, should put in startup?

        // Rescan before doing remove or add drivers
        bus.rescan()
            .map_err(|err| GfxError::Bus("bus rescan error".into(), err))?;

        match vendor {
            GfxVendors::Nvidia | GfxVendors::Hybrid | GfxVendors::Compute => {
                for driver in NVIDIA_DRIVERS.iter() {
                    Self::do_driver_action(driver, "modprobe").map_err(|err| {
                        Self::log_uses_of_nvidia();
                        err
                    })?;
                }
            }
            // TODO: compute mode, needs different setup
            // GfxVendors::Compute => {}
            GfxVendors::Integrated => {
                for driver in NVIDIA_DRIVERS.iter() {
                    Self::do_driver_action(driver, "rmmod")?;
                }
                Self::unbind_remove_nvidia(&devices)?;
            }
        }

        Ok(())
    }

    /// Spools until all user sessions are ended then switches to requested mode
    fn fire_starter(
        vendor: GfxVendors,
        devices: Vec<GraphicsDevice>,
        bus: PciBus,
        killer: mpsc::Receiver<bool>,
    ) -> Result<String, RogError> {
        info!("GFX: display-manager thread started");
        let mut sessions: Vec<session_manager::Session> = get_sessions()?;

        const SLEEP_PERIOD: Duration = Duration::from_millis(300);
        const REFRESH_COUNTDOWN: u32 = 3;
        let mut refresh_sessions = REFRESH_COUNTDOWN;
        while are_gfx_sessions_alive(&sessions) {
            if let Ok(stop) = killer.try_recv() {
                if stop {
                    return Ok("Graphics mode change was cancelled".into());
                }
            }
            // Don't spin at max speed
            sleep(SLEEP_PERIOD);
            if refresh_sessions == 0 {
                refresh_sessions = REFRESH_COUNTDOWN;
                sessions = get_sessions()?;
            }
            refresh_sessions -= 1;
        }
        
        info!("GFX: all graphical user sessions ended, continuing");
        Self::do_display_manager_action("stop")?;

        match Self::wait_display_manager_state("inactive") {
            Ok(_) => info!("GFX: display-manager stopped"),
            Err(err) => {
                warn!("GFX: {}", err);
                warn!("GFX: Retry stop display manager");
                Self::do_display_manager_action("stop")?;
                Self::wait_display_manager_state("inactive")?;
            }
        }

        Self::do_vendor_tasks(vendor, &devices, &bus)?;
        Self::do_display_manager_action("start")?;

        if Self::wait_display_manager_state("active").is_err() {
            error!("GFX: display-manager failed to start normally, attempting restart");
            Self::do_display_manager_action("restart")?;
            Self::wait_display_manager_state("active")?;
        }
        info!("GFX: display-manager started");

        let v: &str = vendor.into();
        info!("GFX: Graphics mode changed to {} successfully", v);
        Ok(format!("Graphics mode changed to {} successfully", v))
    }

    /// Initiates a mode change by starting a thread that will wait until all
    /// graphical sessions are exited before performing the tasks required
    /// to switch modes.
    ///
    /// For manually calling (not on boot/startup) via dbus
    pub fn set_gfx_config(&mut self, vendor: GfxVendors) -> Result<String, RogError> {
        if let Ok(gsync) = CtrlRogBios::get_gfx_mode() {
            if gsync == 1 {
                return Err(GfxError::GsyncModeActive.into());
            }
        }

        if let Ok(lock) = self.thread_kill.lock() {
            if let Some(tx) = lock.as_ref() {
                // Cancel the running thread
                info!("GFX: Cancelling previous thread");
                tx.send(true)
                    .map_err(|err| {
                        warn!("GFX: {}", err);
                    })
                    .ok();
            }
        }

        let devices = self.nvidia.clone();
        let bus = self.bus.clone();
        let (tx, rx) = mpsc::channel();
        if let Ok(mut lock) = self.thread_kill.lock() {
            *lock = Some(tx);
        }
        let killer = self.thread_kill.clone();

        // Save selected mode in case of reboot
        Self::save_gfx_mode(vendor, self.config.clone())?;

        let _join: JoinHandle<()> = std::thread::spawn(move || {
            Self::fire_starter(vendor, devices, bus, rx)
                .map_err(|err| {
                    error!("GFX: {}", err);
                })
                .ok();
            // clear the tx/rx when done
            if let Ok(mut lock) = killer.try_lock() {
                *lock = None;
            }
            return;
        });

        // TODO: undo if failed? Save last mode, catch errors...
        let v: &str = vendor.into();
        Ok(format!("Graphics mode changed to {} successfully", v))
    }

    // if CtrlRogBios::has_dedicated_gfx_toggle() {
    //     if let Ok(config) = self.config.clone().try_lock() {
    //         // Switch to dedicated if config says to do so
    //         if config.gfx_nv_mode_is_dedicated && vendor == GfxVendors::Nvidia {
    //             CtrlRogBios::set_gfx_mode(true)
    //                 .unwrap_or_else(|err| warn!("GFX: Gfx controller: {}", err));
    //         } else if let Ok(ded) = CtrlRogBios::get_gfx_mode() {
    //             // otherwise if switching to non-Nvidia mode turn off dedicated mode
    //             if ded == 1 && vendor != GfxVendors::Nvidia {
    //                 CtrlRogBios::set_gfx_mode(false)
    //                     .unwrap_or_else(|err| warn!("GFX: Gfx controller: {}", err));
    //             }
    //         }
    //     }
    // }

    fn auto_power(&mut self) -> Result<(), RogError> {
        let vendor = self.get_gfx_mode()?;
        let devices = self.nvidia.clone();
        let bus = self.bus.clone();
        Self::do_vendor_tasks(vendor, &devices, &bus)?;
        Self::toggle_fallback_service(vendor)?;
        Ok(())
    }
}