use meilisearch_lib::index_controller::Stats;
use meilisearch_lib::MeiliSearch;
use once_cell::sync::Lazy;
use segment::message::{Identify, Track, User};
use segment::{AutoBatcher, Batcher, HttpClient};
use serde_json::{json, Value};
use std::fmt::Display;
use std::time::{Duration, Instant};
use sysinfo::DiskExt;
use sysinfo::ProcessorExt;
use sysinfo::System;
use sysinfo::SystemExt;
use tokio::sync::Mutex;
use uuid::Uuid;

use crate::Opt;

const SEGMENT_API_KEY: &str = "vHi89WrNDckHSQssyUJqLvIyp2QFITSC";

pub struct Analytics {
    user: User,
    opt: Opt,
    batcher: Mutex<AutoBatcher>,
}

impl Analytics {
    pub fn publish(&'static self, event_name: String, send: Value) {
        tokio::spawn(async move {
            let _ = self
                .batcher
                .lock()
                .await
                .push(Track {
                    user: self.user.clone(),
                    event: event_name.clone(),
                    properties: send,
                    ..Default::default()
                })
                .await;
            println!("ANALYTICS: {} added to batch", event_name)
        });
    }

    pub fn tick(&'static self, meilisearch: MeiliSearch) {
        tokio::spawn(async move {
            loop {
                tokio::time::sleep(Duration::from_secs(60)).await; // 1 minutes
                println!("ANALYTICS: should do things");

                if let Ok(stats) = meilisearch.get_all_stats().await {
                    let traits = Self::compute_traits(&self.opt, stats);
                    let user = self.user.clone();
                    println!("ANALYTICS: Pushing our identify tick");
                    let _ = self
                        .batcher
                        .lock()
                        .await
                        .push(Identify {
                            user,
                            traits,
                            ..Default::default()
                        })
                        .await;
                }
                println!("ANALYTICS: Pushing our batch");
                let _ = self.batcher.lock().await.flush().await;
            }
        });
    }
}

impl Analytics {
    pub async fn new(opt: &Opt, meilisearch: &MeiliSearch) -> &'static Self {
        let user_id = std::fs::read_to_string(opt.db_path.join("user-id"));
        let first_time_run = user_id.is_err();
        let user_id = user_id.unwrap_or(Uuid::new_v4().to_string());
        let _ = std::fs::write(opt.db_path.join("user-id"), user_id.as_bytes());
        let client = HttpClient::default();
        let user = User::UserId {
            user_id: user_id.clone(),
        };
        let batcher = Batcher::new(None);
        let batcher = Mutex::new(AutoBatcher::new(
            client,
            batcher,
            SEGMENT_API_KEY.to_string(),
        ));
        let segment = Box::new(Self {
            user,
            opt: opt.clone(),
            batcher,
        });
        let segment = Box::leak(segment);

        // send an identify event
        let _ = segment
            .batcher
            .lock()
            .await
            .push(Identify {
                user: segment.user.clone(),
                // TODO: TAMO: what should we do when meilisearch is broken at start
                traits: Self::compute_traits(
                    &segment.opt,
                    meilisearch.get_all_stats().await.unwrap(),
                ),
                ..Default::default()
            })
            .await;
        println!("ANALYTICS: pushed the identify event");

        // send the associated track event
        if first_time_run {
            segment.publish("Launched for the first time".to_string(), json!({}));
        }

        // start the runtime tick
        segment.tick(meilisearch.clone());

        segment
    }

    fn compute_traits(opt: &Opt, stats: Stats) -> Value {
        static FIRST_START_TIMESTAMP: Lazy<Instant> = Lazy::new(|| Instant::now());
        static SYSTEM: Lazy<Value> = Lazy::new(|| {
            let mut sys = System::new_all();
            sys.refresh_all();
            json!({
                    "distribution": sys.name().zip(sys.kernel_version()).map(|(name, version)| format!("{}: {}", name, version)),
                    "core_number": sys.processors().len(),
                    "ram_size": sys.total_memory(),
                    "frequency": sys.processors().iter().map(|cpu| cpu.frequency()).sum::<u64>() / sys.processors().len() as u64,
                    "disk_size": sys.disks().iter().map(|disk| disk.available_space()).max(),
                    "server_provider": std::env::var("MEILI_SERVER_PROVIDER").ok(),
            })
        });
        let number_of_documents = stats
            .indexes
            .values()
            .map(|index| index.number_of_documents)
            .collect::<Vec<u64>>();

        json!({
            "system": *SYSTEM,
            "stats": {
                "database_size": stats.database_size,
                "indexes_number": stats.indexes.len(),
                "documents_number": number_of_documents,
            },
            "infos": {
                "version": env!("CARGO_PKG_VERSION").to_string(),
                "env": opt.env.clone(),
                "snapshot": opt.schedule_snapshot,
                "start_since_days": FIRST_START_TIMESTAMP.elapsed().as_secs() / 60 * 60 * 24, // one day
            },
        })
    }
}

impl Display for Analytics {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{:?}", self.user)
    }
}