From 07017c5deff28fc8352c7d65f3b668f17bdfcd72 Mon Sep 17 00:00:00 2001
From: Nathan Rashleigh <ntr@strix.systems>
Date: Wed, 10 Sep 2025 23:03:25 +1000
Subject: [PATCH] ok...

---
 maple-rs/src/db.rs        | 133 ++++++++++++++++++++++++++++++++++++++
 maple-rs/src/main.rs      |  15 +++++
 maple-rs/src/playlists.rs |   6 +-
 3 files changed, 153 insertions(+), 1 deletion(-)
 create mode 100644 maple-rs/src/db.rs
 create mode 100644 maple-rs/src/main.rs

diff --git a/maple-rs/src/db.rs b/maple-rs/src/db.rs
new file mode 100644
index 0000000..113265c
--- /dev/null
+++ b/maple-rs/src/db.rs
@@ -0,0 +1,133 @@
+use std::path::Path;
+use binrw::BinRead;
+use std::collections::BTreeMap;
+
+use binrw::Endian;
+use rekordcrate::pdb::{
+    Header, PageType, Row,
+    Track, TrackId,
+    PlaylistTreeNode, PlaylistTreeNodeId,
+    PlaylistEntry,
+};
+
+#[derive(Debug)]
+pub enum DbError {
+    UnknownPlaylist,
+    UnknownTrack,
+    PositionOutOfBounds,
+}
+
+#[derive(Debug)]
+pub struct Database {
+    pub header: Header,
+    pub tracks: BTreeMap<TrackId, Track>,
+    pub nodes: BTreeMap<PlaylistTreeNodeId, PlaylistTreeNode>,
+    // Keep playlist entries ordered by entry_index
+    pub entries: BTreeMap<PlaylistTreeNodeId, Vec<PlaylistEntry>>,
+}
+
+impl Database {
+    pub fn load_from_pdb(path: impl AsRef<Path>) -> rekordcrate::Result<Self> {
+        let mut f = std::fs::File::open(path)?;
+        let header = Header::read(&mut f)?; // uses the type’s endianness
+
+        let mut tracks: BTreeMap<TrackId, Track> = BTreeMap::new();
+        let mut nodes: BTreeMap<PlaylistTreeNodeId, PlaylistTreeNode> = BTreeMap::new();
+        let mut entries: BTreeMap<PlaylistTreeNodeId, Vec<PlaylistEntry>> = BTreeMap::new();
+
+        for table in &header.tables {
+            let pages = header.read_pages(&mut f, Endian::NATIVE, (&table.first_page, &table.last_page))?;
+
+            for page in pages {
+                for rg in page.row_groups {
+                    for row in rg.present_rows() {
+                        match row {
+                            Row::Track(t) => {
+                                tracks.insert(t.id, t.clone());
+                            }
+                            Row::PlaylistTreeNode(n) => {
+                                nodes.insert(n.id, n.clone());
+                            }
+                            Row::PlaylistEntry(e) => {
+                                entries.entry(e.playlist_id).or_default().push(e.clone());
+                            }
+                            _ => {}
+                        }
+                    }
+                }
+            }
+        }
+
+        // Ensure deterministic ordering within each playlist
+        for v in entries.values_mut() {
+            v.sort_by_key(|e| e.entry_index); // needs `pub entry_index`
+        }
+
+        Ok(Self { header, tracks, nodes, entries })
+    }
+    /// Export to low-level tables.
+    pub fn into_tables(
+        self,
+    ) -> (
+        Header,
+        Vec<Track>,
+        Vec<PlaylistTreeNode>,
+        Vec<(PlaylistTreeNodeId, PlaylistEntry)>,
+    ) {
+        let nodes = self.nodes.into_values().collect();
+        let tracks = self.tracks.into_values().collect();
+        let mut flat_entries = Vec::new();
+        for (pid, vs) in self.entries {
+            for e in vs {
+                flat_entries.push((pid, e));
+            }
+        }
+        (self.header, tracks, nodes, flat_entries)
+    }
+
+    /// Add a ready-made entry (you build it).
+    pub fn add_entry(
+        &mut self,
+        playlist_id: PlaylistTreeNodeId,
+        entry: PlaylistEntry,
+        position: Option<usize>,
+    ) -> Result<(), DbError> {
+        if !self.nodes.contains_key(&playlist_id) {
+            return Err(DbError::UnknownPlaylist);
+        }
+        let vec = self.entries.entry(playlist_id).or_default();
+        match position {
+            Some(i) if i <= vec.len() => vec.insert(i, entry),
+            Some(_) => return Err(DbError::PositionOutOfBounds),
+            None => vec.push(entry),
+        }
+        Ok(())
+    }
+
+    /// Convenience: you pass a track id and a constructor for `PlaylistEntry`.
+    pub fn add_track_to_playlist_with<E>(
+        &mut self,
+        playlist_id: PlaylistTreeNodeId,
+        track_id: TrackId,
+        position: Option<usize>,
+        make_entry: E,
+    ) -> Result<(), DbError>
+    where
+        E: FnOnce(TrackId) -> PlaylistEntry,
+    {
+        if !self.nodes.contains_key(&playlist_id) {
+            return Err(DbError::UnknownPlaylist);
+        }
+        if !self.tracks.contains_key(&track_id) {
+            return Err(DbError::UnknownTrack);
+        }
+        let entry = make_entry(track_id);
+        self.add_entry(playlist_id, entry, position)
+    }
+
+    // fn alloc_node_id(&mut self) -> u32 {
+    //     let id = self.next_node_id;
+    //     self.next_node_id = self.next_node_id.saturating_add(1);
+    //     id
+    // }
+}
diff --git a/maple-rs/src/main.rs b/maple-rs/src/main.rs
new file mode 100644
index 0000000..5555d7c
--- /dev/null
+++ b/maple-rs/src/main.rs
@@ -0,0 +1,15 @@
+mod db;
+
+use db::Database;
+
+// Example
+fn main() -> rekordcrate::Result<()> {
+    let db = Database::load_from_pdb("ntr.pdb")?;
+    println!("tracks: {}, playlists: {}", db.tracks.len(), db.nodes.len());
+
+    for n in db.nodes {
+        println!("{:?}", n);
+    }
+
+    Ok(())
+}
\ No newline at end of file
diff --git a/maple-rs/src/playlists.rs b/maple-rs/src/playlists.rs
index af2019c..3666992 100644
--- a/maple-rs/src/playlists.rs
+++ b/maple-rs/src/playlists.rs
@@ -1,8 +1,12 @@
+mod db;
+
 use binrw::BinRead;
 use std::path::PathBuf;
 use rekordcrate::pdb::{Header, Row, PageType, PlaylistTreeNode, PlaylistTreeNodeId};
 use std::collections::HashMap;
 
+use db::Database;
+
 fn list_playlists(path: &PathBuf) -> rekordcrate::Result<()> {
 
     fn print_children_of(
@@ -67,7 +71,7 @@ fn list_playlists(path: &PathBuf) -> rekordcrate::Result<()> {
 
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
-    let p = PathBuf::from("../data/PIONEER/rekordbox/export.pdb");
+    let p = PathBuf::from("./ntr.pdb");
 
     list_playlists(&p)?;