//! Dönem notları (KAKEIBO_PROMPT §8.6): başlık + Markdown metin, `planning` ya da `review`.

use mongodb::{
    Database,
    bson::{Bson, Document, Uuid, doc},
    options::ReturnDocument,
};

use crate::{
    db::col,
    error::{AppError, AppResult},
    models::{
        common::{new_meta, now, scope},
        note::{Note, NoteContext},
    },
    services::period,
};

pub const MAX_BODY: usize = 20_000;

fn coll(db: &Database) -> mongodb::Collection<Note> {
    db.collection(col::NOTES)
}

/// Dönemin notları (isteğe bağlı sayfa filtresiyle), en yeni değişen başta.
pub async fn list(
    db: &Database,
    household_id: Uuid,
    period_id: Uuid,
    context: Option<NoteContext>,
) -> AppResult<Vec<Note>> {
    period::get(db, household_id, period_id).await?;
    let mut f = scope(household_id);
    f.insert("period_id", period_id);
    if let Some(c) = context {
        f.insert("context", c.as_str());
    }
    let mut cursor = coll(db).find(f).sort(doc! { "updated_at": -1 }).await?;
    let mut out = Vec::new();
    while cursor.advance().await? {
        out.push(cursor.deserialize_current()?);
    }
    Ok(out)
}

pub async fn create(
    db: &Database,
    household_id: Uuid,
    user_id: Uuid,
    period_id: Uuid,
    context: NoteContext,
    title: &str,
    body_md: &str,
) -> AppResult<Note> {
    period::get_open(db, household_id, period_id).await?;
    let mut d = new_meta(household_id);
    let id = d.get("_id").cloned().unwrap_or(Bson::Null);
    d.insert("period_id", period_id);
    d.insert("context", context.as_str());
    d.insert("title", clean_title(title)?);
    d.insert("body_md", clean_body(body_md)?);
    d.insert("created_by", user_id);
    db.collection::<Document>(col::NOTES).insert_one(d).await?;
    coll(db)
        .find_one(doc! { "_id": id })
        .await?
        .ok_or_else(|| AppError::Internal("eklenen not okunamadı".into()))
}

pub async fn update(
    db: &Database,
    household_id: Uuid,
    id: Uuid,
    title: Option<&str>,
    body_md: Option<&str>,
    version: Option<i32>,
) -> AppResult<Note> {
    let current = get(db, household_id, id).await?;
    period::get_open(db, household_id, current.period_id).await?;
    if version.is_some_and(|v| v != current.version) {
        return Err(stale());
    }
    let mut set = doc! { "updated_at": now() };
    if let Some(t) = title {
        set.insert("title", clean_title(t)?);
    }
    if let Some(b) = body_md {
        set.insert("body_md", clean_body(b)?);
    }
    let mut f = scope(household_id);
    f.insert("_id", id);
    f.insert("version", current.version);
    coll(db)
        .find_one_and_update(f, doc! { "$set": set, "$inc": { "version": 1 } })
        .return_document(ReturnDocument::After)
        .await?
        .ok_or_else(stale)
}

pub async fn delete(db: &Database, household_id: Uuid, id: Uuid) -> AppResult<()> {
    let current = get(db, household_id, id).await?;
    period::get_open(db, household_id, current.period_id).await?;
    let ts = now();
    let mut f = scope(household_id);
    f.insert("_id", id);
    db.collection::<Document>(col::NOTES)
        .update_one(
            f,
            doc! { "$set": { "deleted_at": ts, "updated_at": ts }, "$inc": { "version": 1 } },
        )
        .await?;
    Ok(())
}

async fn get(db: &Database, household_id: Uuid, id: Uuid) -> AppResult<Note> {
    let mut f = scope(household_id);
    f.insert("_id", id);
    coll(db).find_one(f).await?.ok_or(AppError::NotFound)
}

fn clean_title(t: &str) -> AppResult<String> {
    let t = t.trim();
    match t.chars().count() {
        0 => Err(AppError::BadRequest("Not başlığı boş olamaz".into())),
        1..=120 => Ok(t.to_string()),
        _ => Err(AppError::BadRequest(
            "Not başlığı en fazla 120 karakter olabilir".into(),
        )),
    }
}

fn clean_body(b: &str) -> AppResult<String> {
    if b.chars().count() > MAX_BODY {
        return Err(AppError::BadRequest(format!(
            "Not metni en fazla {MAX_BODY} karakter olabilir"
        )));
    }
    Ok(b.to_string())
}

fn stale() -> AppError {
    AppError::Conflict("Not başka biri tarafından değiştirildi, sayfayı yenileyin".into())
}