//! İndeksler (DATA_MODEL.md §4). Açılışta her seferinde çağrılır;
//! MongoDB zaten var olan aynı indeksi yeniden oluşturmaz.

use mongodb::{
    Database, IndexModel,
    bson::{Document, doc},
    error::Result,
    options::IndexOptions,
};

use super::col;

pub async fn ensure(db: &Database) -> Result<()> {
    for (collection, indexes) in definitions() {
        db.collection::<Document>(collection)
            .create_indexes(indexes)
            .await?;
    }
    tracing::info!("İndeksler hazır");
    Ok(())
}

fn idx(keys: Document) -> IndexModel {
    IndexModel::builder().keys(keys).build()
}

fn idx_opts(keys: Document, options: IndexOptions) -> IndexModel {
    IndexModel::builder().keys(keys).options(options).build()
}

fn unique() -> IndexOptions {
    IndexOptions::builder().unique(true).build()
}

fn definitions() -> Vec<(&'static str, Vec<IndexModel>)> {
    let hp = || idx(doc! { "household_id": 1, "period_id": 1 });

    let mut defs = vec![
        (col::USERS, vec![idx_opts(doc! { "email": 1 }, unique())]),
        (col::INVITES, vec![idx_opts(doc! { "code": 1 }, unique())]),
        (
            col::PERIODS,
            vec![
                idx(doc! { "household_id": 1, "start_date": 1 }),
                // Hanede en fazla bir açık dönem
                idx_opts(
                    doc! { "household_id": 1 },
                    IndexOptions::builder()
                        .name("one_open_period_per_household".to_string())
                        .unique(true)
                        .partial_filter_expression(doc! { "status": "open" })
                        .build(),
                ),
            ],
        ),
        (
            col::CATEGORIES,
            vec![idx(doc! { "household_id": 1, "sort_order": 1 })],
        ),
        (
            col::PAYMENT_METHODS,
            vec![idx(doc! { "household_id": 1, "sort_order": 1 })],
        ),
        (col::PLAN_ITEMS, vec![hp()]),
        (col::BUDGETS, vec![hp()]),
        (col::NOTES, vec![hp()]),
        (
            col::ENTRIES,
            vec![
                idx(doc! { "household_id": 1, "period_id": 1, "date": 1 }),
                idx(doc! { "household_id": 1, "date": 1 }),
            ],
        ),
        (
            col::CARRYOVERS,
            vec![idx(doc! { "household_id": 1, "to_period_id": 1 })],
        ),
        (
            col::ASSETS,
            vec![idx(doc! { "household_id": 1, "sort_order": 1 })],
        ),
        (
            col::ASSET_TRANSACTIONS,
            vec![idx(doc! { "household_id": 1, "asset_id": 1, "date": 1 })],
        ),
        (
            col::EXCHANGE_RATES,
            vec![idx(doc! { "code": 1, "household_id": 1, "rate_date": -1 })],
        ),
    ];

    // Senkronizasyon (Faz 11): "şu tarihten sonra değişenler" sorgusu.
    for &name in col::HOUSEHOLD_SCOPED {
        let sync = idx(doc! { "household_id": 1, "updated_at": 1 });
        match defs.iter_mut().find(|(c, _)| *c == name) {
            Some((_, list)) => list.push(sync),
            None => defs.push((name, vec![sync])),
        }
    }

    defs
}

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

    #[test]
    fn every_household_collection_has_sync_index() {
        let defs = definitions();
        for &name in col::HOUSEHOLD_SCOPED {
            let (_, list) = defs.iter().find(|(c, _)| *c == name).unwrap();
            assert!(
                list.iter()
                    .any(|i| i.keys == doc! { "household_id": 1, "updated_at": 1 }),
                "{name} koleksiyonunda senkronizasyon indeksi yok"
            );
        }
    }
}