use diesel::prelude::*;
use diesel::sqlite::SqliteConnection;
use std::ops::DerefMut;
use std::sync::{Arc, Mutex};

use crate::database::models::{InsertPhotoInsight, PhotoInsight};
use crate::database::schema;
use crate::database::{DbError, DbErrorKind, connect};
use crate::otel::trace_db_call;

pub trait InsightDao: Sync + Send {
    fn store_insight(
        &mut self,
        context: &opentelemetry::Context,
        insight: InsertPhotoInsight,
    ) -> Result<PhotoInsight, DbError>;

    fn get_insight(
        &mut self,
        context: &opentelemetry::Context,
        file_path: &str,
    ) -> Result<Option<PhotoInsight>, DbError>;

    fn delete_insight(
        &mut self,
        context: &opentelemetry::Context,
        file_path: &str,
    ) -> Result<(), DbError>;

    fn get_all_insights(
        &mut self,
        context: &opentelemetry::Context,
    ) -> Result<Vec<PhotoInsight>, DbError>;
}

pub struct SqliteInsightDao {
    connection: Arc<Mutex<SqliteConnection>>,
}

impl Default for SqliteInsightDao {
    fn default() -> Self {
        Self::new()
    }
}

impl SqliteInsightDao {
    pub fn new() -> Self {
        SqliteInsightDao {
            connection: Arc::new(Mutex::new(connect())),
        }
    }
}

impl InsightDao for SqliteInsightDao {
    fn store_insight(
        &mut self,
        context: &opentelemetry::Context,
        insight: InsertPhotoInsight,
    ) -> Result<PhotoInsight, DbError> {
        trace_db_call(context, "insert", "store_insight", |_span| {
            use schema::photo_insights::dsl::*;

            let mut connection = self.connection.lock().expect("Unable to get InsightDao");

            // Insert or replace on conflict (UNIQUE constraint on file_path)
            diesel::replace_into(photo_insights)
                .values(&insight)
                .execute(connection.deref_mut())
                .map_err(|_| anyhow::anyhow!("Insert error"))?;

            // Retrieve the inserted record
            photo_insights
                .filter(file_path.eq(&insight.file_path))
                .first::<PhotoInsight>(connection.deref_mut())
                .map_err(|_| anyhow::anyhow!("Query error"))
        })
        .map_err(|_| DbError::new(DbErrorKind::InsertError))
    }

    fn get_insight(
        &mut self,
        context: &opentelemetry::Context,
        path: &str,
    ) -> Result<Option<PhotoInsight>, DbError> {
        trace_db_call(context, "query", "get_insight", |_span| {
            use schema::photo_insights::dsl::*;

            let mut connection = self.connection.lock().expect("Unable to get InsightDao");

            photo_insights
                .filter(file_path.eq(path))
                .first::<PhotoInsight>(connection.deref_mut())
                .optional()
                .map_err(|_| anyhow::anyhow!("Query error"))
        })
        .map_err(|_| DbError::new(DbErrorKind::QueryError))
    }

    fn delete_insight(
        &mut self,
        context: &opentelemetry::Context,
        path: &str,
    ) -> Result<(), DbError> {
        trace_db_call(context, "delete", "delete_insight", |_span| {
            use schema::photo_insights::dsl::*;

            let mut connection = self.connection.lock().expect("Unable to get InsightDao");

            diesel::delete(photo_insights.filter(file_path.eq(path)))
                .execute(connection.deref_mut())
                .map(|_| ())
                .map_err(|_| anyhow::anyhow!("Delete error"))
        })
        .map_err(|_| DbError::new(DbErrorKind::QueryError))
    }

    fn get_all_insights(
        &mut self,
        context: &opentelemetry::Context,
    ) -> Result<Vec<PhotoInsight>, DbError> {
        trace_db_call(context, "query", "get_all_insights", |_span| {
            use schema::photo_insights::dsl::*;

            let mut connection = self.connection.lock().expect("Unable to get InsightDao");

            photo_insights
                .order(generated_at.desc())
                .load::<PhotoInsight>(connection.deref_mut())
                .map_err(|_| anyhow::anyhow!("Query error"))
        })
        .map_err(|_| DbError::new(DbErrorKind::QueryError))
    }
}