fix: improve export_to_event parameter handling for multi-log files

CRATE_USAGE.md

@@ -8,6 +8,7 @@ Focused guidance for using the bbl_parser Rust crate.
 - [Basic usage](#basic-usage)
 - [Multi-log processing](#multi-log-processing)
 - [Parsing from memory](#parsing-from-memory)
+- [Export functionality](#export-functionality)
 - [Examples](#examples)
 - [Notes](#notes)
 
@@ -78,6 +79,143 @@ fn main() -> anyhow::Result<()> {
 }
 ```
 
+## Export functionality
+
+The crate now provides full export capabilities for CSV, GPX, and Event data formats.
+
+### CSV Export
+
+Export parsed log data to CSV files (flight data + headers):
+
+```rust
+use bbl_parser::{parse_bbl_file, export_to_csv, ExportOptions};
+use std::path::Path;
+
+fn main() -> anyhow::Result<()> {
+    let export_opts = ExportOptions {
+        csv: true,
+        gpx: false,
+        event: false,
+        output_dir: Some("output".to_string()),
+        force_export: false,
+    };
+
+    let log = parse_bbl_file(Path::new("flight.BBL"), export_opts.clone(), false)?;
+    export_to_csv(&log, Path::new("flight.BBL"), &export_opts)?;
+    println!("CSV exported successfully");
+    Ok(())
+}
+```
+
+This creates two files:
+- `flight.csv` - Main flight data with blackbox_decode compatible format
+- `flight.headers.csv` - Complete header information
+
+### GPX Export
+
+Export GPS data to GPX format for mapping applications:
+
+```rust
+use bbl_parser::{parse_bbl_file, export_to_gpx, ExportOptions};
+use std::path::Path;
+
+fn main() -> anyhow::Result<()> {
+    let export_opts = ExportOptions {
+        csv: false,
+        gpx: true,
+        event: false,
+        output_dir: None,
+        force_export: false,
+    };
+
+    let log = parse_bbl_file(Path::new("flight.BBL"), export_opts.clone(), false)?;
+
+    if !log.gps_coordinates.is_empty() {
+        export_to_gpx(
+            Path::new("flight.BBL"),
+            0,  // log index
+            log.total_logs,
+            &log.gps_coordinates,
+            &log.home_coordinates,
+            &export_opts
+        )?;
+        println!("GPX exported successfully");
+    }
+    Ok(())
+}
+```
+
+### Event Export
+
+Export flight events to JSONL format:
+
+```rust
+use bbl_parser::{parse_bbl_file, export_to_event, ExportOptions};
+use std::path::Path;
+
+fn main() -> anyhow::Result<()> {
+    let export_opts = ExportOptions {
+        csv: false,
+        gpx: false,
+        event: true,
+        output_dir: None,
+        force_export: false,
+    };
+
+    let log = parse_bbl_file(Path::new("flight.BBL"), export_opts.clone(), false)?;
+
+    if !log.event_frames.is_empty() {
+        export_to_event(
+            Path::new("flight.BBL"),
+            0,  // log index
+            log.total_logs,
+            &log.event_frames,
+            &export_opts
+        )?;
+        println!("Events exported successfully");
+    }
+    Ok(())
+}
+```
+
+### Complete Export Example
+
+Export all formats at once:
+
+```rust
+use bbl_parser::{parse_bbl_file, export_to_csv, export_to_gpx, export_to_event, ExportOptions};
+use std::path::Path;
+
+fn main() -> anyhow::Result<()> {
+    let export_opts = ExportOptions {
+        csv: true,
+        gpx: true,
+        event: true,
+        output_dir: Some("output".to_string()),
+        force_export: false,
+    };
+
+    let input_path = Path::new("flight.BBL");
+    let log = parse_bbl_file(input_path, export_opts.clone(), false)?;
+
+    // Export CSV
+    export_to_csv(&log, input_path, &export_opts)?;
+
+    // Export GPX if GPS data exists
+    if !log.gps_coordinates.is_empty() {
+        export_to_gpx(input_path, 0, log.total_logs, &log.gps_coordinates, &log.home_coordinates, &export_opts)?;
+    }
+
+    // Export events if event data exists
+    if !log.event_frames.is_empty() {
+        export_to_event(input_path, 0, log.total_logs, &log.event_frames, &export_opts)?;
+    }
+
+    println!("All exports completed successfully");
+    Ok(())
+}
+```
+
 ## Examples
 
 Run the crate example that demonstrates multi-firmware support and PID extraction:

OVERVIEW.md

@@ -77,24 +77,22 @@ The BBL parser implements a streaming architecture designed for memory efficienc
 - **E-frames:** Flight events with official Betaflight FlightLogEvent enum mapping
 
 ### **Export Functionality**
-- **CSV Export:** blackbox_decode compatible format with proper field ordering (CLI functional, crate stub)
-- **GPX Export:** Standard GPS exchange format for mapping applications (CLI functional)
-- **Event Export:** JSONL format with Betaflight event type descriptions (CLI functional)
-
-**Note:** Export functionality is currently implemented in the CLI (`src/main.rs`). Crate-level export functions in `src/export.rs` are stubs pending systematic migration.
+- **CSV Export:** blackbox_decode compatible format with proper field ordering (CLI and crate functional)
+- **GPX Export:** Standard GPS exchange format for mapping applications (CLI and crate functional)
+- **Event Export:** JSONL format with Betaflight event type descriptions (CLI and crate functional)
 
 ### **Encoding Support**
 BBL encoding compatibility: `SIGNED_VB`, `UNSIGNED_VB`, `NEG_14BIT`, `TAG8_8SVB`, `TAG2_3S32`, `TAG8_4S16`
 
 ### **Project Structure**
 ```text
 src/
-├── main.rs              # CLI interface, file handling, statistics, CSV export
+├── main.rs              # CLI interface, file handling, statistics
 ├── lib.rs               # Library API exports and documentation
 ├── bbl_format.rs        # BBL binary format decoding and encoding
 ├── conversion.rs        # Unit conversions (GPS coordinates, altitude, speed)
 ├── error.rs             # Error handling and result types
-├── export.rs            # Export function stubs (CSV/GPX/Event migration in progress)
+├── export.rs            # Export functions for CSV/GPX/Event formats
 ├── types/               # Core data structures
 │   ├── mod.rs          #   Module definitions and re-exports
 │   ├── log.rs          #   BBLLog container type
@@ -127,7 +125,7 @@ src/
 - **Serde Integration:** Optional serialization support for data structures
 - **Rust Crate:** Available as library dependency for 3rd party projects
 
-### **Data Export Capabilities (CLI)**
+### **Data Export Capabilities (CLI and Crate)**
 - **CSV Export:** blackbox_decode compatible field ordering and formatting
   - Main flight data `[.XX].csv` with proper field order and "time (us)" column
   - Headers `[.XX].headers.csv` with complete configuration