use serde::{Deserialize, Serialize};
use std::collections::HashMap;

/// Full manifest describing how an object is stored across erasure-coded shards.
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct ObjectManifest {
    /// Bucket name
    pub bucket: String,
    /// Object key
    pub key: String,
    /// Unique version ID for this write
    pub version_id: String,
    /// Total object size in bytes
    pub size: u64,
    /// MD5 hex digest of the complete object
    pub content_md5: String,
    /// Content type
    pub content_type: String,
    /// User metadata (x-amz-meta-*, content-type, etc.)
    pub metadata: HashMap<String, String>,
    /// When the object was created
    pub created_at: String,
    /// Last modified timestamp
    pub last_modified: String,
    /// Number of data shards used
    pub data_shards: usize,
    /// Number of parity shards used
    pub parity_shards: usize,
    /// Chunk size in bytes (last chunk may be smaller)
    pub chunk_size: usize,
    /// Per-chunk shard placement info
    pub chunks: Vec<ChunkManifest>,
}

/// Describes the shards for a single chunk of an object.
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct ChunkManifest {
    /// Index of this chunk (0-based)
    pub chunk_index: u32,
    /// Actual data size of this chunk (before erasure coding)
    pub data_size: usize,
    /// Where each shard was placed
    pub shard_placements: Vec<ShardPlacement>,
}

/// Describes where a specific shard is stored.
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct ShardPlacement {
    /// Shard index within the erasure set (0..data_shards+parity_shards)
    pub shard_index: u32,
    /// Node that holds this shard
    pub node_id: String,
    /// Drive ID on that node
    pub drive_id: String,
    /// CRC32C checksum of the shard data
    pub checksum: u32,
    /// Size of the shard data in bytes
    pub shard_size: usize,
}

/// Manifest for a multipart upload in progress.
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct MultipartUploadManifest {
    pub upload_id: String,
    pub bucket: String,
    pub key: String,
    pub initiated: String,
    pub metadata: HashMap<String, String>,
    /// Per-part manifests, keyed by part number.
    pub parts: HashMap<u32, PartManifest>,
}

/// Manifest for a single part of a multipart upload.
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct PartManifest {
    pub part_number: u32,
    pub size: u64,
    pub md5: String,
    pub chunks: Vec<ChunkManifest>,
}