feat(import): introduce /api/v1/import endpoint to support batch EML email import

src/modules/import/mod.rs

@@ -0,0 +1,162 @@
+use poem_openapi::Object;
+use serde::{Deserialize, Serialize};
+use tantivy::doc;
+
+use crate::{
+    base64_decode_url_safe,
+    modules::{
+        account::migration::{AccountModel, AccountType},
+        cache::imap::mailbox::{Attribute, AttributeEnum, MailBox},
+        envelope::extractor::extract_envelope_from_eml,
+        error::{code::ErrorCode, BichonResult},
+        indexer::{
+            manager::{EML_INDEX_MANAGER, ENVELOPE_INDEX_MANAGER},
+            schema::SchemaTools,
+        },
+        utils::create_hash,
+    },
+    raise_error,
+};
+
+#[derive(Debug, Clone, Default, Eq, PartialEq, Serialize, Deserialize, Object)]
+pub struct BatchEmlRequest {
+    pub account_id: u64,
+    pub mail_folder: String,
+    /// A list of emails in base64-encoded format. Each element represents one .eml file.
+    pub emls: Vec<String>,
+}
+
+#[derive(Debug, Clone, Default, Eq, PartialEq, Serialize, Deserialize, Object)]
+pub struct FailedEmlDetail {
+    /// The 0-based index of the failed EML in the request list
+    pub index: usize,
+    /// The error message that caused the import to fail
+    pub error_message: String,
+}
+
+#[derive(Debug, Clone, Default, Eq, PartialEq, Serialize, Deserialize, Object)]
+pub struct BatchEmlResult {
+    /// Total number of emails processed
+    pub total: usize,
+    /// Number of emails successfully imported
+    pub success: usize,
+    /// Number of emails failed to import
+    pub failed: usize,
+    /// A list of details for failed imports
+    pub failed_details: Vec<FailedEmlDetail>,
+}
+
+pub struct ImportEmls;
+
+impl ImportEmls {
+    pub async fn do_import(request: BatchEmlRequest) -> BichonResult<BatchEmlResult> {
+        let account = AccountModel::check_account_exists(request.account_id).await?;
+        
+        if !account.enabled {
+            return Err(raise_error!("The account is disabled and cannot be used for this operation.".into(), ErrorCode::InvalidParameter));
+        }
+
+        let mailbox_id = match account.account_type {
+            AccountType::IMAP => {
+                let all_mailboxes = MailBox::list_all(account.id).await?;
+                let mailbox = all_mailboxes.into_iter().find(|m| m.name == request.mail_folder);
+                
+                match mailbox {
+                    Some(mailbox) => mailbox.id,
+                    None => return Err(raise_error!(
+                        format!("Mail folder '{}' not found for account ID {}. The target folder must exist before importing.", 
+                                request.mail_folder, 
+                                request.account_id).into(),
+                        ErrorCode::ResourceNotFound
+                    )),
+                }
+            },
+            AccountType::NoSync => {
+                let mailbox = MailBox {
+                    id: create_hash(request.account_id, &request.mail_folder),
+                    account_id: request.account_id,
+                    name: request.mail_folder.clone(),
+                    delimiter: Some("/".to_string()),
+                    attributes: vec![Attribute {
+                        attr: AttributeEnum::Extension,
+                        extension: Some("CreatedByBichon".into()),
+                    }],
+                    exists: 0,
+                    unseen: None,
+                    uid_next: None,
+                    uid_validity: None,
+                };
+                let mailbox_id = mailbox.id;
+                // Upsert the mailbox, creating it if it doesn't exist
+                MailBox::batch_upsert(&[mailbox]).await?;
+                mailbox_id
+            },
+        };
+
+        let fields = SchemaTools::eml_fields();
+        let account_id = account.id;
+        let mut success_count = 0;
+        let mut failed_details: Vec<FailedEmlDetail> = Vec::new(); // Store failure details
+
+        let total = request.emls.len();
+        for (index, eml_base64) in request.emls.into_iter().enumerate() {
+            // 1. Decode Base64
+            let decoded = match base64_decode_url_safe!(eml_base64.as_bytes()) {
+                Ok(bytes) => bytes,
+                Err(e) => {
+                    let error_msg =
+                        format!("Failed to decode base64 EML at index {}: {:?}", index, e);
+                    tracing::error!("{}", error_msg);
+                    failed_details.push(FailedEmlDetail {
+                        index,
+                        error_message: error_msg,
+                    });
+                    continue;
+                }
+            };
+
+            let envelope = match extract_envelope_from_eml(&decoded, account_id, mailbox_id) {
+                Ok(env) => env,
+                Err(e) => {
+                    let error_msg = format!(
+                        "Failed to extract envelope from EML at index {}: {:?}",
+                        index, e
+                    );
+                    tracing::error!("{}", error_msg);
+                    failed_details.push(FailedEmlDetail {
+                        index,
+                        error_message: error_msg,
+                    });
+                    continue;
+                }
+            };
+
+            ENVELOPE_INDEX_MANAGER
+                .add_document(envelope.id, envelope.to_document(mailbox_id).unwrap())
+                .await;
+
+            EML_INDEX_MANAGER
+                .add_document(
+                    envelope.id,
+                    doc!(
+                        fields.f_id => envelope.id,
+                        fields.f_account_id => account_id,
+                        fields.f_mailbox_id => mailbox_id,
+                        fields.f_eml => decoded
+                    ),
+                )
+                .await;
+
+            success_count += 1;
+        }
+
+        let failed_count = failed_details.len();
+
+        Ok(BatchEmlResult {
+            total,
+            success: success_count,
+            failed: failed_count,
+            failed_details, // Return the list of failure details
+        })
+    }
+}