use anyhow::{Context, Result};
use diesel::{QueryDsl, RunQueryDsl, SelectableHelper, SqliteConnection};
use schist_models::category::Category;
use schist_schema::schema::categories::{self as categories_schema, dsl::categories as categories_table};

pub fn delete_all_categories(connection: &mut SqliteConnection) -> Result<usize> {
    let num_rows_deleted = diesel::delete(categories_table)
        .execute(connection)
        .with_context(|| "failed to delete all categories")?;
    Ok(num_rows_deleted)
}

pub fn get_all_categories(connection: &mut SqliteConnection) -> Result<Vec<Category>> {
    let all_categories = categories_table
        .select(Category::as_select())
        .load(connection)
        .with_context(|| "failed to get all categories")?;
    Ok(all_categories)
}

pub fn get_all_category_ids(connection: &mut SqliteConnection) -> Result<Vec<i32>> {
    let all_category_ids = categories_table
        .select(categories_schema::id)
        .load(connection)
        .with_context(|| "failed to get all category IDs")?;
    Ok(all_category_ids)
}

pub fn insert_categories(
    categories: &[Category],
    connection: &mut SqliteConnection,
) -> Result<usize> {
    let num_categories_inserted = diesel::insert_into(categories_table)
        .values(categories)
        .execute(connection)
        .with_context(|| insert_err_msg(categories))?;
    Ok(num_categories_inserted)
}

fn insert_err_msg(categories: &[Category]) -> String {
    format!(
        "failed to insert categories: [{}]",
        categories
            .iter()
            .map(|c| format!("\"{}\": \"{}\"", c.id, c.name))
            .collect::<Vec<String>>()
            .join(", ")
    )
}