//! Utility functions on the DBs. Mainly getter and setters.

use milli::{
    heed::{RoTxn, RwTxn},
    BEU32,
};
use roaring::RoaringBitmap;

use crate::{
    task::{Kind, Status},
    Error, IndexScheduler, Result, Task, TaskId,
};

impl IndexScheduler {
    pub(crate) fn get_task(&self, rtxn: &RoTxn, task_id: TaskId) -> Result<Option<Task>> {
        Ok(self.all_tasks.get(rtxn, &BEU32::new(task_id))?)
    }

    /// Convert an iterator to a `Vec` of tasks. The tasks MUST exist or a
    /// `CorruptedTaskQueue` error will be throwed.
    pub(crate) fn get_existing_tasks(
        &self,
        rtxn: &RoTxn,
        tasks: impl IntoIterator<Item = TaskId>,
    ) -> Result<Vec<Task>> {
        tasks
            .into_iter()
            .map(|task_id| {
                self.get_task(rtxn, task_id)
                    .and_then(|task| task.ok_or(Error::CorruptedTaskQueue))
            })
            .collect::<Result<_>>()
    }

    pub(crate) fn get_index(&self, rtxn: &RoTxn, index: &str) -> Result<RoaringBitmap> {
        Ok(self.index_tasks.get(&rtxn, index)?.unwrap_or_default())
    }

    pub(crate) fn put_index(
        &self,
        wtxn: &mut RwTxn,
        index: &str,
        bitmap: &RoaringBitmap,
    ) -> Result<()> {
        Ok(self.index_tasks.put(wtxn, index, bitmap)?)
    }

    pub(crate) fn get_status(&self, rtxn: &RoTxn, status: Status) -> Result<RoaringBitmap> {
        Ok(self.status.get(&rtxn, &status)?.unwrap_or_default())
    }

    pub(crate) fn put_status(
        &self,
        wtxn: &mut RwTxn,
        status: Status,
        bitmap: &RoaringBitmap,
    ) -> Result<()> {
        Ok(self.status.put(wtxn, &status, bitmap)?)
    }

    pub(crate) fn get_kind(&self, rtxn: &RoTxn, kind: Kind) -> Result<RoaringBitmap> {
        Ok(self.kind.get(&rtxn, &kind)?.unwrap_or_default())
    }

    pub(crate) fn put_kind(
        &self,
        wtxn: &mut RwTxn,
        kind: Kind,
        bitmap: &RoaringBitmap,
    ) -> Result<()> {
        Ok(self.kind.put(wtxn, &kind, bitmap)?)
    }

    pub(crate) fn update_status(
        &self,
        wtxn: &mut RwTxn,
        status: Status,
        f: impl Fn(RoaringBitmap) -> RoaringBitmap,
    ) -> Result<()> {
        let tasks = self.get_status(&wtxn, status)?;
        let tasks = f(tasks);
        self.put_status(wtxn, status, &tasks)?;

        Ok(())
    }

    pub(crate) fn update_kind(
        &self,
        wtxn: &mut RwTxn,
        kind: Kind,
        f: impl Fn(RoaringBitmap) -> RoaringBitmap,
    ) -> Result<()> {
        let tasks = self.get_kind(&wtxn, kind)?;
        let tasks = f(tasks);
        self.put_kind(wtxn, kind, &tasks)?;

        Ok(())
    }
}