tinycortex 0.1.1

//! One-shot SQLite migrations for the chunk DB.
//!
//! Each migration is version-gated via `PRAGMA user_version` so it runs exactly
//! once per vault. Called from [`super::connection`] during DB initialisation.

use anyhow::{Context, Result};
use rusqlite::Connection;

use super::embeddings::{
    active_embedding_dims, set_chunk_embedding_for_signature_tx,
    set_summary_embedding_for_signature_tx, tree_active_signature,
};
use super::{content_root, GLOBAL_TOPIC_PURGE_MIGRATION_VERSION, TREE_EMBEDDING_MIGRATION_VERSION};
use crate::memory::config::MemoryConfig;

/// One-shot migration: copy legacy per-chunk/summary `.embedding` blobs into the
/// normalised `mem_tree_chunk_embeddings` / `mem_tree_summary_embeddings` sidecar
/// tables.
///
/// Version-gated: `PRAGMA user_version < TREE_EMBEDDING_MIGRATION_VERSION`
/// triggers the copy; otherwise it is a no-op. Dim-mismatched rows are skipped
/// (left for a later re-embed backfill); the legacy column is preserved.
pub(super) fn migrate_legacy_embeddings_to_sidecar(
    conn: &Connection,
    config: &MemoryConfig,
) -> Result<()> {
    let version: i64 = conn
        .query_row("PRAGMA user_version", [], |r| r.get(0))
        .context("read PRAGMA user_version for embedding migration")?;
    if version >= TREE_EMBEDDING_MIGRATION_VERSION {
        return Ok(());
    }

    let sig = tree_active_signature(config);
    let dims = active_embedding_dims(config);

    let tx = conn.unchecked_transaction()?;

    for (table, is_chunk) in [("mem_tree_chunks", true), ("mem_tree_summaries", false)] {
        let mut stmt = tx.prepare(&format!(
            "SELECT id, embedding FROM {table} WHERE embedding IS NOT NULL"
        ))?;
        let rows = stmt.query_map([], |r| {
            Ok((r.get::<_, String>(0)?, r.get::<_, Vec<u8>>(1)?))
        })?;
        for row in rows {
            let (id, blob) = row?;
            if !blob.len().is_multiple_of(4) {
                continue;
            }
            if blob.len() / 4 != dims {
                // Different embedding space — unrecoverable from the blob; leave
                // for a later re-embed backfill.
                continue;
            }
            let vec: Vec<f32> = blob
                .chunks_exact(4)
                .map(|c| f32::from_le_bytes([c[0], c[1], c[2], c[3]]))
                .collect();
            if is_chunk {
                set_chunk_embedding_for_signature_tx(&tx, &id, &sig, &vec)?;
            } else {
                set_summary_embedding_for_signature_tx(&tx, &id, &sig, &vec)?;
            }
        }
    }

    tx.commit()?;
    conn.pragma_update(None, "user_version", TREE_EMBEDDING_MIGRATION_VERSION)
        .context("set PRAGMA user_version after embedding migration")?;
    Ok(())
}

/// One-shot purge of the removed global + topic trees.
///
/// The global (time-axis) and topic (subject-axis) trees were deleted in favour
/// of source trees. This removes their now-orphaned DB rows and on-disk summary
/// folders so old vaults clean themselves up on next open. Version-gated via
/// `PRAGMA user_version`; a no-op on workspaces that never had those trees.
pub(super) fn purge_global_topic_trees(conn: &Connection, config: &MemoryConfig) -> Result<()> {
    let version: i64 = conn
        .query_row("PRAGMA user_version", [], |r| r.get(0))
        .context("read PRAGMA user_version for global/topic purge")?;
    if version >= GLOBAL_TOPIC_PURGE_MIGRATION_VERSION {
        return Ok(());
    }

    let tx = conn.unchecked_transaction()?;
    tx.execute(
        "DELETE FROM mem_tree_summary_embeddings WHERE summary_id IN \
         (SELECT id FROM mem_tree_summaries WHERE tree_kind IN ('global','topic'))",
        [],
    )?;
    tx.execute(
        "DELETE FROM mem_tree_summary_reembed_skipped WHERE summary_id IN \
         (SELECT id FROM mem_tree_summaries WHERE tree_kind IN ('global','topic'))",
        [],
    )?;
    tx.execute(
        "DELETE FROM mem_tree_entity_index WHERE tree_id IN \
         (SELECT id FROM mem_tree_trees WHERE kind IN ('global','topic'))",
        [],
    )?;
    tx.execute(
        "DELETE FROM mem_tree_summaries WHERE tree_kind IN ('global','topic')",
        [],
    )?;
    tx.execute(
        "DELETE FROM mem_tree_buffers WHERE tree_id IN \
         (SELECT id FROM mem_tree_trees WHERE kind IN ('global','topic'))",
        [],
    )?;
    tx.execute(
        "DELETE FROM mem_tree_trees WHERE kind IN ('global','topic')",
        [],
    )?;
    tx.execute(
        "DELETE FROM mem_tree_jobs WHERE kind IN ('topic_route','digest_daily')",
        [],
    )?;
    tx.commit()?;

    // On-disk: drop `wiki/summaries/global*` and `topic-*` summary folders.
    // Best-effort — a filesystem error must not abort the version bump.
    let summaries_root = content_root(config).join("wiki").join("summaries");
    if let Ok(entries) = std::fs::read_dir(&summaries_root) {
        for entry in entries.flatten() {
            let name = entry.file_name();
            let name = name.to_string_lossy();
            if name.starts_with("global") || name.starts_with("topic-") {
                let _ = std::fs::remove_dir_all(entry.path());
            }
        }
    }

    conn.pragma_update(None, "user_version", GLOBAL_TOPIC_PURGE_MIGRATION_VERSION)
        .context("set PRAGMA user_version after global/topic purge")?;
    Ok(())
}