Add export-session CLI command for exporting session transcripts to JSON (#84)

This adds a new CLI command `export-session` that exports a specific
session to JSON format using the build_session_transcript function.

- Make build_session_transcript public in data_collector.rs
- Add ExportSession command variant to CLI Commands enum
- Implement handle_export_session_command handler in query.rs
- Supports output to file (--output) or stdout

Co-authored-by: Claude <noreply@anthropic.com>

Author: sanggggg

src/cli/mod.rs

@@ -78,6 +78,15 @@ pub enum Commands {
         session_id: String,
     },
 
+    /// Export a session transcript to JSON file
+    ExportSession {
+        /// Session ID to export
+        session_id: String,
+        /// Output file path (prints to stdout if not specified)
+        #[arg(short, long)]
+        output: Option<String>,
+    },
+
     /// Search messages by content
     Search {
         /// Search query
@@ -300,6 +309,10 @@ impl Cli {
                     query::handle_session_detail_command(session_id).await
                 }
 
+                Commands::ExportSession { session_id, output } => {
+                    query::handle_export_session_command(session_id, output).await
+                }
+
                 Commands::Search {
                     query,
                     limit,

src/cli/query.rs

@@ -1,5 +1,8 @@
-use crate::database::DatabaseManager;
+use crate::database::{
+    ChatSessionRepository, DatabaseManager, MessageRepository, ToolOperationRepository,
+};
 use crate::models::Message;
+use crate::services::analytics::build_session_transcript;
 use crate::services::{QueryService, SearchRequest, SessionDetailRequest, SessionsQueryRequest};
 use crate::utils::time_parser;
 use anyhow::Result;
@@ -306,6 +309,47 @@ fn is_tool_message(content: &str) -> bool {
         || content.trim().starts_with("[Tool Result]")
 }
 
+/// Export a session transcript to JSON
+pub async fn handle_export_session_command(
+    session_id: String,
+    output: Option<String>,
+) -> Result<()> {
+    let db_path = crate::database::config::get_default_db_path()?;
+    let db_manager = DatabaseManager::new(&db_path).await?;
+
+    // Get repositories
+    let session_repo = ChatSessionRepository::new(&db_manager);
+    let message_repo = MessageRepository::new(&db_manager);
+    let tool_op_repo = ToolOperationRepository::new(&db_manager);
+
+    // Parse session_id to UUID
+    let session_uuid = uuid::Uuid::parse_str(&session_id)
+        .map_err(|e| anyhow::anyhow!("Invalid session ID format: {e}"))?;
+
+    // Get session data
+    let session = session_repo
+        .get_by_id(&session_uuid)
+        .await?
+        .ok_or_else(|| anyhow::anyhow!("Session not found: {session_id}"))?;
+
+    // Get messages and tool operations
+    let messages = message_repo.get_by_session(&session_uuid).await?;
+    let tool_operations = tool_op_repo.get_by_session(&session_uuid).await?;
+
+    // Build the session transcript
+    let transcript = build_session_transcript(&messages, &tool_operations, &session)?;
+
+    // Output to file or stdout
+    if let Some(output_path) = output {
+        std::fs::write(&output_path, &transcript)?;
+        println!("Session exported to: {output_path}");
+    } else {
+        println!("{transcript}");
+    }
+
+    Ok(())
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

src/services/analytics/data_collector.rs

@@ -54,7 +54,8 @@ pub async fn collect_qualitative_data(
 // =============================================================================
 
 /// Builds a JSON string representation of the session transcript with embedded tool uses.
-fn build_session_transcript(
+/// This is the public API for exporting session transcripts.
+pub fn build_session_transcript(
     messages: &[Message],
     tool_operations: &[ToolOperation],
     session: &ChatSession,