use actix_web::web;
use chrono::Utc;
use log::{error, info};
use sqlx::{
    migrate, postgres::PgPoolOptions, query, query_as, types::mac_address::MacAddress, Pool,
    Postgres,
};
use thiserror::Error;

use crate::schemas::{
    Device, TelemetryMessage, TelemetryMessageFromDevice, ValueMessage, ValueMessageFromDevice,
};

#[derive(Clone)]
pub struct Database {
    conn_pool: Pool<Postgres>,
}

#[derive(Error, Debug)]
pub enum DatabaseError {
    #[error("Generic SQLX Error")]
    SqlxError(#[from] sqlx::Error),
}

impl Database {
    pub async fn init(database_url: &str) -> Database {
        match PgPoolOptions::new()
            .max_connections(10)
            .connect(database_url)
            .await
        {
            Ok(pool) => {
                info!("Connection to the database is successful!");
                Database { conn_pool: pool }
            }
            Err(err) => {
                error!("Failed to connect to the database: {err:?}");
                std::process::exit(1);
            }
        }
    }

    #[cfg(test)]
    pub fn init_from_pool(pool: Pool<Postgres>) -> Database {
        Database { conn_pool: pool }
    }

    // Check if the necessary tables exist. If not, create them. TODO auto-migration
    pub async fn init_db(&self) {
        info!("Checking if required tables exist");
        match migrate!().run(&self.conn_pool).await {
            Ok(()) => {}
            Err(e) => {
                error!("Error when running migrations {e}");
                std::process::exit(1);
            }
        };
    }

    pub async fn add_device(&self, device_id: &MacAddress) -> Result<(), DatabaseError> {
        info!("Adding device with the ID {}", &device_id);
        query!("INSERT INTO Devices (ID) VALUES ($1);", device_id)
            .execute(&self.conn_pool)
            .await?;
        Ok(())
    }

     #[allow(dead_code)]
    pub async fn update_display_name(
        &self,
        device_id: &MacAddress,
        display_name: &str,
    ) -> Result<(), DatabaseError> {
        info!("Updating Displayname to {display_name} for Device with ID {device_id}");
        query!(
            "UPDATE Devices SET display_name = $1 WHERE id = $2;",
            display_name,
            device_id
        )
        .execute(&self.conn_pool)
        .await?;
        Ok(())
    }

    pub async fn create_device_if_not_exists(
        &self,
        device_id: &MacAddress,
    ) -> Result<(), DatabaseError> {
        info!("Checking if device with the ID {} exists", &device_id);
        let exists_result = query!("SELECT count(*) FROM devices WHERE ID = $1;", device_id)
            .fetch_one(&self.conn_pool)
            .await;

        let exists = match exists_result {
            Ok(res) => res.count > Some(0),
            Err(err) => {
                error!("Error checking table existence: {err:?}");
                std::process::exit(1);
            }
        };

        if exists {
            info!("Device exists");
            Ok(())
        } else {
            info!("Device does not exist");
            self.add_device(device_id).await?;
            Ok(())
        }
    }

    pub async fn add_telemetry(
        &self,
        msg: &web::Json<TelemetryMessageFromDevice>,
        device_id: &MacAddress,
    ) -> Result<(), DatabaseError> {
        info!("Adding telemetry message to DB");
        let current_timestamp = Utc::now().naive_utc();
        query!("INSERT INTO Telemetry (timestamp, software_version, voltage, temperature, uptime, device_id) 
        VALUES ($1, $2, $3, $4, $5, $6);", 
        current_timestamp, msg.software_version, msg.voltage, msg.temperature, msg.uptime, device_id
        ).execute(&self.conn_pool).await?;
        Ok(())
    }

    pub async fn get_telemetry_for_id(
        &self,
        device_id: &MacAddress,
    ) -> Result<Vec<TelemetryMessage>, DatabaseError> {
        info!("Getting telemetry messages for {} from DB", &device_id);
        let messages = query_as!(
            TelemetryMessage,
            "SELECT timestamp, software_version, voltage, temperature, uptime 
            FROM Telemetry 
            WHERE device_id = $1 ORDER BY timestamp DESC;",
            &device_id
        )
        .fetch_all(&self.conn_pool)
        .await?;

        Ok(messages)
    }

    pub async fn add_value(
        &self,
        msg: &ValueMessageFromDevice,
        device_id: &MacAddress,
    ) -> Result<(), DatabaseError> {
        info!("Adding value to DB");
        let current_timestamp = Utc::now().naive_utc();
        query!(
            "
        INSERT INTO values (timestamp, value, device_id, active_errors, value_id)
        VALUES ($1, $2, $3, $4, $5);",
            current_timestamp,
            msg.value,
            device_id,
            msg.active_errors,
            msg.value_id
        )
        .execute(&self.conn_pool)
        .await?;

        Ok(())
    }

    pub async fn get_values_for_id(
        &self,
        device_id: &MacAddress,
    ) -> Result<Vec<ValueMessage>, DatabaseError> {
        info!("Getting values for {} from DB", &device_id);
        let values = query_as!(
            ValueMessage,
            "SELECT timestamp, value, value_id 
            FROM Values 
            WHERE device_id = $1 ORDER BY timestamp DESC;",
            &device_id
        )
        .fetch_all(&self.conn_pool)
        .await?;

        Ok(values)
    }

    pub async fn get_devices(&self) -> Result<Vec<Device>, DatabaseError> {
        info!("Getting all devices");
        let devices = query_as!(
            Device,
            "SELECT id, display_name 
            FROM Devices;",
        )
        .fetch_all(&self.conn_pool)
        .await?;

        Ok(devices)
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use sqlx::PgPool;

    #[sqlx::test]
    async fn add_device_and_display_name(pool: PgPool) {
        let db = Database::init_from_pool(pool);

        let test_device = Device {
            display_name: Some("Waterlevel daheim".to_owned()),
            id: MacAddress::from([0x1A, 0x2B, 0x3C, 0x4D, 0x5E, 0x6F]),
        };
        db.add_device(&MacAddress::from([0x1A, 0x2B, 0x3C, 0x4D, 0x5E, 0x6F]))
            .await
            .unwrap();
        db.update_display_name(
            &MacAddress::from([0x1A, 0x2B, 0x3C, 0x4D, 0x5E, 0x6F]),
            "Waterlevel daheim",
        )
        .await
        .unwrap();

        let devices = db.get_devices().await.unwrap();
        assert_eq!(test_device, devices[0]);
    }

    #[sqlx::test]
    async fn add_value(pool: PgPool) {
        let db = Database::init_from_pool(pool);
        let device_id = MacAddress::from([0x1A, 0x2B, 0x3C, 0x4D, 0x5E, 0x6F]);

        db.add_device(&device_id).await.unwrap();
        let msg = ValueMessageFromDevice {
            active_errors: 0,
            value: 112.0,
            value_id: 1,
        };
        db.add_value(&msg, &device_id).await.unwrap();

        let values = db.get_values_for_id(&device_id).await.unwrap();

        assert!((values[0].value - msg.value).abs() < 1e-5);
        assert_eq!(values[0].value_id, msg.value_id);
    }
}