/*
 * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <hello@stalw.art>
 *
 * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
 */

use super::metadata::MessageData;
use crate::cache::{MessageCacheFetch, email::MessageCacheAccess};
use common::{Server, storage::index::ObjectIndexBuilder};
use groupware::calendar::storage::ItipAutoExpunge;
use registry::schema::enums::IndexDocumentType;
use registry::schema::structs::{Task, TaskIndexDocument, TaskStatus};
use std::future::Future;
use store::write::key::DeserializeBigEndian;
use store::write::{IndexPropertyClass, now};
use store::{IterateParams, U32_LEN, U64_LEN, ValueKey};
use store::{
    roaring::RoaringBitmap,
    write::{BatchBuilder, ValueClass},
};
use trc::AddContext;
use types::collection::{Collection, SyncCollection, VanishedCollection};
use types::field::{EmailField, EmailSubmissionField};

pub trait EmailDeletion: Sync + Send {
    fn emails_delete(
        &self,
        account_id: u32,
        tenant_id: Option<u32>,
        batch: &mut BatchBuilder,
        document_ids: RoaringBitmap,
    ) -> impl Future<Output = trc::Result<RoaringBitmap>> + Send;

    fn purge_account(&self, account_id: u32) -> impl Future<Output = trc::Result<()>> + Send;

    fn purge_email_submissions(
        &self,
        account_id: u32,
        hold_period: u64,
    ) -> impl Future<Output = trc::Result<()>> + Send;

    fn emails_auto_expunge(
        &self,
        account_id: u32,
        hold_period: u64,
    ) -> impl Future<Output = trc::Result<()>> + Send;

    fn log_emptied_threads(
        &self,
        account_id: u32,
        batch: &mut BatchBuilder,
        thread_ids: RoaringBitmap,
        deleted_ids: &RoaringBitmap,
    ) -> impl Future<Output = trc::Result<()>> + Send;
}

impl EmailDeletion for Server {
    async fn emails_delete(
        &self,
        account_id: u32,
        tenant_id: Option<u32>,
        batch: &mut BatchBuilder,
        document_ids: RoaringBitmap,
    ) -> trc::Result<RoaringBitmap> {
        let mut deleted_ids = RoaringBitmap::new();
        let mut thread_ids = RoaringBitmap::new();
        batch
            .with_account_id(account_id)
            .with_collection(Collection::Email);
        self.archives(
            account_id,
            Collection::Email,
            &document_ids,
            |document_id, data_| {
                // Add changes to batch
                let metadata = data_
                    .to_unarchived::<MessageData>()
                    .caused_by(trc::location!())?;
                for mailbox in metadata.inner.mailboxes.iter() {
                    batch.log_vanished_item(
                        VanishedCollection::Email,
                        (mailbox.mailbox_id.to_native(), mailbox.uid.to_native()),
                    );
                }
                thread_ids.insert(metadata.inner.thread_id.to_native());
                batch
                    .with_document(document_id)
                    .custom(
                        ObjectIndexBuilder::<_, ()>::new()
                            .with_tenant_id(tenant_id)
                            .with_current(metadata),
                    )
                    .caused_by(trc::location!())?
                    .schedule_task(Task::UnindexDocument(TaskIndexDocument {
                        account_id: account_id.into(),
                        document_id: document_id.into(),
                        document_type: IndexDocumentType::Email,
                        status: TaskStatus::now(),
                    }))
                    .commit_point();

                deleted_ids.insert(document_id);

                Ok(true)
            },
        )
        .await?;

        self.log_emptied_threads(account_id, batch, thread_ids, &deleted_ids)
            .await?;

        let not_destroyed = if document_ids.len() == deleted_ids.len() {
            RoaringBitmap::new()
        } else {
            deleted_ids ^= document_ids;
            deleted_ids
        };

        Ok(not_destroyed)
    }

    async fn log_emptied_threads(
        &self,
        account_id: u32,
        batch: &mut BatchBuilder,
        thread_ids: RoaringBitmap,
        deleted_ids: &RoaringBitmap,
    ) -> trc::Result<()> {
        if !thread_ids.is_empty() {
            let cache = self
                .get_cached_messages(account_id)
                .await
                .caused_by(trc::location!())?;
            for thread_id in &thread_ids {
                if cache
                    .in_thread(thread_id)
                    .all(|message| deleted_ids.contains(message.document_id))
                {
                    batch
                        .with_account_id(account_id)
                        .with_collection(Collection::Thread)
                        .with_document(thread_id)
                        .log_container_delete(SyncCollection::Thread);
                }
            }
        }

        Ok(())
    }

    async fn purge_account(&self, account_id: u32) -> trc::Result<()> {
        // Auto-expunge deleted and junk messages
        if let Some(hold_period) = self.core.email.mail_autoexpunge_after {
            self.emails_auto_expunge(account_id, hold_period)
                .await
                .caused_by(trc::location!())?;
        }

        // Auto-expunge iMIP messages
        if let Some(hold_period) = self.core.groupware.itip_inbox_auto_expunge {
            self.itip_auto_expunge(account_id, hold_period)
                .await
                .caused_by(trc::location!())?;
        }

        // Delete old e-mail submissions
        if let Some(hold_period) = self.core.email.email_submission_autoexpunge_after {
            self.purge_email_submissions(account_id, hold_period)
                .await
                .caused_by(trc::location!())?;
        }

        // Purge changelogs
        self.delete_changes(
            account_id,
            self.core.email.changes_max_history,
            self.core.email.share_notification_max_history,
        )
        .await
        .caused_by(trc::location!())?;

        Ok(())
    }

    async fn emails_auto_expunge(&self, account_id: u32, hold_period: u64) -> trc::Result<()> {
        // Filter messages by received date
        let mut destroy_ids = RoaringBitmap::new();
        let cutoff = now().saturating_sub(hold_period);
        self.store()
            .iterate(
                IterateParams::new(
                    ValueKey {
                        account_id,
                        collection: Collection::Email.into(),
                        document_id: 0,
                        class: ValueClass::Property(EmailField::DeletedAt.into()),
                    },
                    ValueKey {
                        account_id,
                        collection: Collection::Email.into(),
                        document_id: u32::MAX,
                        class: ValueClass::Property(EmailField::DeletedAt.into()),
                    },
                )
                .ascending(),
                |key, value| {
                    let deleted_at = value.deserialize_be_u64(0)?;
                    if deleted_at <= cutoff {
                        destroy_ids.insert(key.deserialize_be_u32(key.len() - U32_LEN)?);
                    }

                    Ok(true)
                },
            )
            .await
            .caused_by(trc::location!())?;

        if destroy_ids.is_empty() {
            return Ok(());
        }

        trc::event!(
            Store(trc::StoreEvent::AutoExpunge),
            Collection = Collection::Email.as_str(),
            AccountId = account_id,
            Total = destroy_ids.len(),
        );

        // Delete messages
        let mut batch = BatchBuilder::new();
        let tenant_id = self
            .account(account_id)
            .await
            .caused_by(trc::location!())?
            .tenant_id();
        self.emails_delete(account_id, tenant_id, &mut batch, destroy_ids)
            .await?;
        self.commit_batch(batch).await?;
        self.notify_task_queue();

        Ok(())
    }

    async fn purge_email_submissions(&self, account_id: u32, hold_period: u64) -> trc::Result<()> {
        // Filter messages by received date
        let mut destroy_ids = Vec::new();
        self.store()
            .iterate(
                IterateParams::new(
                    ValueKey {
                        account_id,
                        collection: Collection::EmailSubmission.into(),
                        document_id: 0,
                        class: ValueClass::IndexProperty(IndexPropertyClass::Integer {
                            property: EmailSubmissionField::Metadata.into(),
                            value: 0,
                        }),
                    },
                    ValueKey {
                        account_id,
                        collection: Collection::Email.into(),
                        document_id: u32::MAX,
                        class: ValueClass::IndexProperty(IndexPropertyClass::Integer {
                            property: EmailSubmissionField::Metadata.into(),
                            value: now().saturating_sub(hold_period),
                        }),
                    },
                )
                .ascending()
                .no_values(),
                |key, _| {
                    destroy_ids.push((
                        key.deserialize_be_u32(key.len() - U32_LEN)?,
                        key.deserialize_be_u64(key.len() - U32_LEN - U64_LEN)?,
                    ));

                    Ok(true)
                },
            )
            .await
            .caused_by(trc::location!())?;

        if destroy_ids.is_empty() {
            return Ok(());
        }

        trc::event!(
            Store(trc::StoreEvent::AutoExpunge),
            Collection = Collection::EmailSubmission.as_str(),
            AccountId = account_id,
            Total = destroy_ids.len(),
        );

        // Delete messages
        let mut batch = BatchBuilder::new();
        batch
            .with_account_id(account_id)
            .with_collection(Collection::EmailSubmission);

        for (document_id, send_at) in destroy_ids {
            batch
                .with_document(document_id)
                .clear(EmailSubmissionField::Metadata)
                .clear(ValueClass::IndexProperty(IndexPropertyClass::Integer {
                    property: EmailSubmissionField::Metadata.into(),
                    value: send_at,
                }))
                .commit_point();
        }

        self.commit_batch(batch).await?;

        Ok(())
    }
}