use std::sync::{Arc, Mutex};
use serde_json::{Result, Value};
use serde::{Deserialize, Serialize};

use rusqlite::{params, Connection};

use super::analytic_service::analytic_unit::{types::{AnalyticUnitConfig, self}, threshold_analytic_unit::ThresholdAnalyticUnit, pattern_analytic_unit::PatternAnalyticUnit, anomaly_analytic_unit::AnomalyAnalyticUnit};

#[derive(Clone)]
pub struct AnalyticUnitService {
    connection: Arc<Mutex<Connection>>
}

impl AnalyticUnitService {
    pub fn new() -> anyhow::Result<AnalyticUnitService> {
        // TODO: remove repetitoin with segment_service
        std::fs::create_dir_all("./data").unwrap();
        let conn = Connection::open("./data/analytic_units.db")?;

        // TODO: add learning results field
        conn.execute(
            "CREATE TABLE IF NOT EXISTS analytic_unit (
                      id              TEXT PRIMARY KEY,
                      last_detection  INTEGER
                      active          BOOLEAN
                      type            INTEGER
                      config          TEXT
                 )",
            [],
        )?;

        Ok(AnalyticUnitService {
            connection: Arc::new(Mutex::new(conn)),
        })
    }

    // TODO: optional id
    pub fn resolve_au(&self, cfg: &AnalyticUnitConfig) -> Box<dyn types::AnalyticUnit + Send + Sync> {
        match cfg {
            AnalyticUnitConfig::Threshold(c) => Box::new(ThresholdAnalyticUnit::new("1".to_string(), c.clone())),
            AnalyticUnitConfig::Pattern(c) => Box::new(PatternAnalyticUnit::new("2".to_string(), c.clone())),
            AnalyticUnitConfig::Anomaly(c) => Box::new(AnomalyAnalyticUnit::new("3".to_string(), c.clone())),
        }
    }

    // TODO: get id of analytic_unit which be used also as it's type
    pub fn resolve(&self, cfg: AnalyticUnitConfig) -> anyhow::Result<Box<dyn types::AnalyticUnit + Send + Sync>> {
        let au = self.resolve_au(&cfg);
        let id = au.as_ref().get_id();

        let conn = self.connection.lock().unwrap();
        let mut stmt = conn.prepare(
            "SELECT id from analytic_unit WHERE id = ?1",
        )?;
        let res = stmt.exists(params![id])?;

        if res == false {
            let cfg_json = serde_json::to_string(&cfg)?;
            conn.execute(
            "INSERT INTO analytic_unit (id, type, config) VALUES (?1, ?1, ?2)",
            params![id, cfg_json]
            )?;
        }

        conn.execute(
            "UPDATE analytic_unit set active = FALSE where active = TRUE",
            params![]
        )?;
        conn.execute(
            "UPDATE analytic_unit set active = TRUE where id = ?1",
            params![id]
        )?;

        return Ok(au);
    }

    // TODO: resolve with saving by id
    pub fn set_last_detection(&self, id: String, last_detection: u64) -> anyhow::Result<()> {
        let conn = self.connection.lock().unwrap();
        conn.execute(
            "UPDATE analytic_unit SET last_detection = ?1 WHERE id = ?2",
            params![last_detection, id]
        )?;
        Ok(())
    }

    pub fn get_active(&self) -> anyhow::Result<Box<dyn types::AnalyticUnit + Send + Sync>> {
        let conn = self.connection.lock().unwrap();
        let mut stmt = conn.prepare(
            "SELECT id, type, config from analytic_unit WHERE active = TRUE"
        )?;

        let au = stmt.query_row([], |row| {
            let c: String = row.get(2)?;
            let cfg = serde_json::from_str(&c).unwrap();
            Ok(self.resolve(cfg))
        })?;

        return Ok(au);

    }
}