//! Data types and associated methods for monitoring and configuring go-sbot.

use std::{fs, fs::File, io::Write, process::Command, str};

use serde::{Deserialize, Serialize};

use crate::error::PeachError;

/// go-sbot process status.
#[derive(Debug, Serialize, Deserialize)]
pub struct SbotStatus {
    /// Current process state.
    pub state: Option<String>,
    /// Current process boot state.
    pub boot_state: Option<String>,
    /// Current process memory usage in bytes.
    pub memory: Option<u32>,
    /// Uptime for the process (if state is `active`).
    pub uptime: Option<String>,
    /// Downtime for the process (if state is `inactive`).
    pub downtime: Option<String>,
}

impl SbotStatus {
    /// Default builder for `SbotStatus`.
    fn default() -> Self {
        Self {
            state: None,
            boot_state: None,
            memory: None,
            uptime: None,
            downtime: None,
        }
    }

    /// Retrieve statistics for the go-sbot systemd process by querying `systemctl`.
    pub fn read() -> Result<Self, PeachError> {
        let mut status = SbotStatus::default();

        let info_output = Command::new("/usr/bin/systemctl")
            .arg("--user")
            .arg("show")
            .arg("go-sbot.service")
            .arg("--no-page")
            .output()?;

        let service_info = std::str::from_utf8(&info_output.stdout)?;

        for line in service_info.lines() {
            if line.starts_with("ActiveState=") {
                if let Some(state) = line.strip_prefix("ActiveState=") {
                    status.state = Some(state.to_string())
                }
            } else if line.starts_with("MemoryCurrent=") {
                if let Some(memory) = line.strip_prefix("MemoryCurrent=") {
                    status.memory = memory.parse().ok()
                }
            }
        }

        let status_output = Command::new("/usr/bin/systemctl")
            .arg("--user")
            .arg("status")
            .arg("go-sbot.service")
            .output()?;

        let service_status = str::from_utf8(&status_output.stdout)?;
        //.map_err(PeachError::Utf8ToStr)?;

        for line in service_status.lines() {
            // example of the output line we're looking for:
            // `Loaded: loaded (/home/glyph/.config/systemd/user/go-sbot.service; enabled; vendor
            // preset: enabled)`
            if line.contains("Loaded:") {
                let before_boot_state = line.find(';');
                let after_boot_state = line.rfind(';');
                if let (Some(start), Some(end)) = (before_boot_state, after_boot_state) {
                    // extract the enabled / disabled from the `Loaded: ...` line
                    // using the index of the first ';' + 2 and the last ';'
                    status.boot_state = Some(line[start + 2..end].to_string());
                }
            // example of the output line we're looking for here:
            // `Active: active (running) since Mon 2022-01-24 16:22:51 SAST; 4min 14s ago`
            } else if line.contains("Active:") {
                let before_time = line.find(';');
                let after_time = line.find(" ago");
                if let (Some(start), Some(end)) = (before_time, after_time) {
                    // extract the uptime / downtime from the `Active: ...` line
                    // using the index of ';' + 2 and the index of " ago"
                    let time = Some(&line[start + 2..end]);
                    // if service is active then the `time` reading is uptime
                    if status.state == Some("active".to_string()) {
                        status.uptime = time.map(|t| t.to_string())
                    // if service is inactive then the `time` reading is downtime
                    } else if status.state == Some("inactive".to_string()) {
                        status.downtime = time.map(|t| t.to_string())
                    }
                }
            }
        }

        Ok(status)
    }
}

#[derive(Debug, Serialize, Deserialize)]
pub struct SbotConfig {
    // TODO: maybe define as a Path type?
    /// Directory path for the log and indexes.
    repo: Option<String>,
    /// Directory path for writing debug output.
    debugdir: Option<String>,
    /// Secret-handshake app-key (aka. network key).
    shscap: Option<String>,
    /// HMAC hash used to sign messages.
    hmac: Option<String>,
    /// Replication hops (1: friends, 2: friends of friends).
    hops: Option<u8>,
    /// Address to listen on.
    lis: Option<String>,
    /// Address to listen on for WebSocket connections.
    wslis: Option<String>,
    /// Address to for metrics and pprof HTTP server.
    debuglis: Option<String>,
    /// Enable sending local UDP broadcasts.
    localadv: Option<bool>,
    /// Enable listening for UDP broadcasts and connecting.
    localdiscov: Option<bool>,
    /// Enable syncing by using epidemic-broadcast-trees (EBT).
    #[serde(rename = "enable-ebt")]
    enable_ebt: Option<bool>,
    /// Bypass graph auth and fetch remote's feed (useful for pubs that are restoring their data
    /// from peer; user beware - caveats about).
    promisc: Option<bool>,
    /// Disable the UNIX socket RPC interface.
    nounixsock: Option<bool>,
}

impl SbotConfig {
    pub fn read() -> Result<Self, PeachError> {
        // determine path of user's home directory
        let mut config_path = dirs::home_dir().ok_or(PeachError::HomeDir)?;
        config_path.push(".ssb-go/config.toml");

        let config_contents = fs::read_to_string(config_path)?;

        let config: SbotConfig = toml::from_str(&config_contents)?;

        Ok(config)
    }

    pub fn write(config: SbotConfig) -> Result<(), PeachError> {
        // convert the provided `SbotConfig` instance to a string
        let config_string = toml::to_string(&config)?;

        // determine path of user's home directory
        let mut config_path = dirs::home_dir().ok_or(PeachError::HomeDir)?;
        config_path.push(".ssb-go/config.toml");

        // open config file for writing
        let mut file = File::create(config_path)?;

        // write the config string to file
        write!(file, "{}", config_string)?;

        Ok(())
    }
}