MIDI Analyzer MCP Server

use anyhow::{anyhow, Result}; use sha2::{Digest, Sha256}; use crate::model::AnalyzerCache; pub fn sha256_hex(bytes: &[u8]) -> String { let mut h = Sha256::new(); h.update(bytes); let digest = h.finalize(); format!("sha256:{}", base16ct::lower::encode_string(&digest)) } pub fn guess_ext_is_midi(path: &str) -> bool { let p = path.to_ascii_lowercase(); p.ends_with(".mid") || p.ends_with(".midi") || p.ends_with(".rmi") } pub fn ticks_to_seconds(ticks: u64, ppq: u64, tempo_map: &[(u64, f64)]) -> Option<f64> { if tempo_map.is_empty() { return None; } let mut last_tick = 0u64; let mut last_bpm = tempo_map[0].1; let mut acc = 0.0f64; for (tk, bpm) in tempo_map.iter().cloned().chain(std::iter::once((ticks, last_bpm))) { if tk < last_tick { continue; } let dt = (tk - last_tick) as f64; let sec_per_tick = (60.0 / last_bpm) / (ppq as f64); acc += dt * sec_per_tick; last_tick = tk; last_bpm = bpm; } Some(acc) } pub async fn resolve_bytes_and_id<'a>(args: &'a serde_json::Value, cache: &'a mut AnalyzerCache) -> Result<(Vec<u8>, String)> { if let Some(fid) = args.get("file_id").and_then(|v| v.as_str()) { if let Some(a) = cache.by_id.get(fid) { // We don't store bytes; caller must provide path if bytes are needed. Return empty bytes. return Ok((Vec::new(), a.file_id.clone())); } else if let Some(alias) = cache.by_alias.get(fid) { if let Some(a) = cache.by_id.get(alias) { return Ok((Vec::new(), a.file_id.clone())); } } return Err(anyhow!("file_id not found: {}", fid)); } if let Some(path) = args.get("path").and_then(|v| v.as_str()) { let bytes = tokio::fs::read(path).await?; let fid = sha256_hex(&bytes); Ok((bytes, fid)) } else { Err(anyhow!("either file_id or path is required")) } }