1 files changed, 250 insertions, 0 deletions
diff --git a/src/chunker/rw/storage/build.rs b/src/chunker/rw/storage/build.rs
new file mode 100644
index 0000000..7608b5c
--- /dev/null
+++ b/src/chunker/rw/storage/build.rs
@@ -0,0 +1,250 @@
+use futures::future::join_all;
+use just_progress::progress;
+use log::{error, info, trace};
+use memmap2::Mmap;
+use std::path::PathBuf;
+use tokio::{fs::File, io::AsyncWriteExt};
+
+use crate::{
+    chunker::{
+        constants::{BUTCK_INDEX_FILE_SUFFIX, BUTCK_INDEX_MAGIC},
+        context::ButckContext,
+        rw::error::{ButckRWError, ButckRWErrorKind},
+        rw::storage,
+    },
+    utils::size_display::size_display,
+};
+
+pub async fn build(ctx: ButckContext) -> Result<(), ButckRWError> {
+    if ctx.storage_path.is_none() {
+        return Err(ButckRWErrorKind::NoButckStorageFound.pack(ctx));
+    }
+    if ctx.file_paths.is_empty() {
+        return Err(
+            ButckRWErrorKind::RebuildFailed("No bidx files specified".to_string()).pack(ctx),
+        );
+    }
+
+    let tasks: Vec<_> = ctx
+        .file_paths
+        .iter()
+        .map(|bidx_path| async {
+            trace!(
+                "Preparing to rebuild from bidx file `{}`",
+                bidx_path.display()
+            );
+            rebuild_from_bidx(bidx_path, &ctx).await
+        })
+        .collect();
+
+    let results = join_all(tasks).await;
+
+    for result in results {
+        if let Err(e) = result {
+            return Err(e.pack(ctx));
+        }
+    }
+
+    Ok(())
+}
+
+async fn rebuild_from_bidx(
+    bidx_path: &PathBuf,
+    ctx: &ButckContext,
+) -> Result<(), ButckRWErrorKind> {
+    // Validate file extension
+    if let Some(ext) = bidx_path.extension()
+        && ext != BUTCK_INDEX_FILE_SUFFIX
+    {
+        return Err(ButckRWErrorKind::InvalidBidxFormat);
+    }
+
+    info!("Rebuilding from bidx file: {}", bidx_path.display());
+
+    // Read bidx file content
+    let bidx_content = if ctx.memmap_read {
+        let file = File::open(bidx_path).await?;
+        let mmap = unsafe { Mmap::map(&file)? };
+        mmap.to_vec()
+    } else {
+        tokio::fs::read(bidx_path).await?
+    };
+
+    // Verify file size includes at least the header
+    if bidx_content.len() < 6 {
+        return Err(ButckRWErrorKind::InvalidBidxFormat);
+    }
+
+    // Validate MAGIC bytes
+    if bidx_content[0..4] != BUTCK_INDEX_MAGIC {
+        return Err(ButckRWErrorKind::InvalidBidxFormat);
+    }
+
+    // Read filename
+    let filename_len = u16::from_le_bytes([bidx_content[4], bidx_content[5]]) as usize;
+    if bidx_content.len() < 6 + filename_len {
+        return Err(ButckRWErrorKind::InvalidBidxFormat);
+    }
+    let filename_bytes = &bidx_content[6..6 + filename_len];
+    let original_filename = String::from_utf8(filename_bytes.to_vec())
+        .map_err(|_| ButckRWErrorKind::InvalidBidxFormat)?;
+
+    trace!("Original filename from bidx: {}", original_filename);
+
+    let hash_data_start = 6 + filename_len;
+    let hash_data = &bidx_content[hash_data_start..];
+
+    // Verify that hash data size is a multiple of 32 bytes
+    if hash_data.len() % 32 != 0 {
+        return Err(ButckRWErrorKind::InvalidBidxFormat);
+    }
+
+    let chunk_count = hash_data.len() / 32;
+    info!("Found {} chunks in bidx file", chunk_count);
+
+    let mut chunk_hashes = Vec::with_capacity(chunk_count);
+    for i in 0..chunk_count {
+        let start = i * 32;
+        let end = start + 32;
+        let hash_bytes: [u8; 32] = hash_data[start..end]
+            .try_into()
+            .map_err(|_| ButckRWErrorKind::InvalidBidxFormat)?;
+        chunk_hashes.push(hash_bytes);
+    }
+
+    trace!("Parsed {} chunk hashes", chunk_hashes.len());
+
+    // Determine output file path
+    let output_path = if let Some(output_file) = &ctx.output_file {
+        output_file.clone()
+    } else {
+        // Use the original filename read from the bidx file
+        storage::generate_unique_path(&ctx.output_dir, &original_filename)
+    };
+
+    info!("Rebuilding file to: {}", output_path.display());
+
+    let progress_name = format!("Rebuild `{}`", output_path.display());
+    progress::update_progress(progress_name.as_str(), 0.0);
+    let step = 1.0 / chunk_count as f64;
+
+    let mut tasks = Vec::with_capacity(chunk_count);
+
+    for (index, hash_bytes) in chunk_hashes.iter().enumerate() {
+        let hash_hex = hex::encode(hash_bytes);
+        tasks.push(read_chunk(
+            progress_name.as_str(),
+            step,
+            hash_hex,
+            &ctx.output_dir,
+            index,
+        ));
+    }
+
+    trace!("Starting parallel read of {} chunks", tasks.len());
+    let results = join_all(tasks).await;
+    trace!("All read tasks completed");
+
+    // Collect chunk data and verify order
+    let mut chunk_data_list = Vec::with_capacity(chunk_count);
+    let mut success_count = 0;
+
+    for (index, result) in results.into_iter().enumerate() {
+        match result {
+            Ok(chunk_data) => {
+                let chunk_size = chunk_data.len();
+                success_count += 1;
+                chunk_data_list.push((index, chunk_data));
+                trace!(
+                    "Chunk {} read successfully, size: {} bytes",
+                    index, chunk_size
+                );
+            }
+            Err(e) => {
+                error!("Failed to read chunk {}: {:?}", index, e);
+                return Err(e);
+            }
+        }
+    }
+
+    if success_count != chunk_count {
+        return Err(ButckRWErrorKind::ChunkNotFound(format!(
+            "Only {}/{} chunks found in storage",
+            success_count, chunk_count
+        )));
+    }
+
+    info!("All {} chunks read successfully", success_count);
+
+    // Sort by index and concatenate files
+    chunk_data_list.sort_by_key(|(index, _)| *index);
+
+    // Calculate total size
+    let total_size: usize = chunk_data_list.iter().map(|(_, data)| data.len()).sum();
+    let (total_value, total_unit) = size_display(total_size);
+    info!(
+        "Rebuilding file: {} chunks, total size: {:.2} {} ({} bytes)",
+        chunk_count, total_value, total_unit, total_size
+    );
+
+    // Write to output file
+    trace!("Writing to output file: {}", output_path.display());
+    let mut output_file = File::create(&output_path).await?;
+
+    for (index, chunk_data) in chunk_data_list {
+        trace!("Writing chunk {} ({} bytes)", index, chunk_data.len());
+        output_file.write_all(&chunk_data).await?;
+        progress::increase(progress_name.as_str(), step as f32);
+    }
+
+    output_file.flush().await?;
+
+    info!("File successfully rebuilt: {}", output_path.display());
+    progress::complete(progress_name.as_str());
+
+    Ok(())
+}
+
+/// Read a single chunk from storage
+async fn read_chunk(
+    progress_name: &str,
+    step: f64,
+    hash_hex: String,
+    storage_dir: &PathBuf,
+    chunk_index: usize,
+) -> Result<Vec<u8>, ButckRWErrorKind> {
+    trace!("read_chunk[{}]: Starting, hash: {}", chunk_index, hash_hex);
+
+    // Build chunk file path
+    let file_path = storage::get_chunk_path(storage_dir, &hash_hex);
+
+    trace!(
+        "read_chunk[{}]: Looking for file at: {}",
+        chunk_index,
+        file_path.display()
+    );
+
+    // Read chunk file
+    match tokio::fs::read(&file_path).await {
+        Ok(data) => {
+            trace!(
+                "read_chunk[{}]: Read {} bytes successfully",
+                chunk_index,
+                data.len()
+            );
+            progress::increase(progress_name, step as f32);
+            Ok(data)
+        }
+        Err(e) if e.kind() == std::io::ErrorKind::NotFound => {
+            trace!("read_chunk[{}]: File not found", chunk_index);
+            Err(ButckRWErrorKind::ChunkNotFound(format!(
+                "Chunk {} (hash: {}) not found in storage",
+                chunk_index, hash_hex
+            )))
+        }
+        Err(e) => {
+            trace!("read_chunk[{}]: Read failed: {:?}", chunk_index, e);
+            Err(ButckRWErrorKind::IOError(e))
+        }
+    }
+}