talon-core 0.4.1

//! `SQLite` schema initialization for the Talon index.
//!
//! Talon is still pre-consumer, so the database schema is treated as a single
//! current shape. Existing incompatible development indexes should be deleted
//! and rebuilt rather than migrated forward.
//!
//! The schema is split into two statement groups for readability:
//!
//! 1. [`SCHEMA_MIGRATIONS`] — tables, virtual tables, and indexes.
//! 2. [`TRIGGER_MIGRATIONS`] — FTS5 sync triggers and seed metadata.
//!
//! `vec_chunks` is intentionally absent — it is created lazily by the
//! embedding pipeline once the embedding dimensionality is known.

use rusqlite::{Connection, params};

use crate::TalonError;

/// Settings key under which the schema version is stored.
pub const DB_VERSION_KEY: &str = "db_version";

/// Default `busy_timeout` PRAGMA value, in milliseconds.
pub const TALON_SQLITE_BUSY_TIMEOUT_MS: u32 = 10_000;

/// Schema-defining DDL: tables and indexes.
pub const SCHEMA_MIGRATIONS: &[&str] = &[
    "CREATE TABLE IF NOT EXISTS notes (
       id          INTEGER PRIMARY KEY,
       vault_path  TEXT UNIQUE NOT NULL,
       title       TEXT,
       tags        TEXT,
       aliases     TEXT,
       content     TEXT NOT NULL,
       frontmatter TEXT NOT NULL DEFAULT '',
       mtime_ms    INTEGER NOT NULL,
       size_bytes  INTEGER NOT NULL,
       hash        TEXT NOT NULL,
       docid       TEXT NOT NULL,
       active      INTEGER NOT NULL DEFAULT 1,
       scope       TEXT NOT NULL DEFAULT ''
     )",
    "CREATE TABLE IF NOT EXISTS chunks (
       id               INTEGER PRIMARY KEY,
       note_id          INTEGER NOT NULL REFERENCES notes(id) ON DELETE CASCADE,
       chunk_index      INTEGER NOT NULL,
       text             TEXT NOT NULL,
       embedding_text   TEXT NOT NULL,
       heading_path     TEXT,
       char_start       INTEGER,
       char_end          INTEGER,
       line_start       INTEGER,
       line_end         INTEGER,
       chunk_hash       TEXT NOT NULL,
       token_estimate   INTEGER NOT NULL,
       embedding_status TEXT NOT NULL DEFAULT 'pending',
       UNIQUE(note_id, chunk_index)
     )",
    "CREATE TABLE IF NOT EXISTS links (
       from_path  TEXT NOT NULL,
       to_path    TEXT NOT NULL,
       raw_target TEXT,
       heading    TEXT,
       alias      TEXT,
       PRIMARY KEY (from_path, to_path, raw_target)
     )",
    "CREATE TABLE IF NOT EXISTS note_aliases (
       note_id    INTEGER NOT NULL REFERENCES notes(id) ON DELETE CASCADE,
       alias      TEXT NOT NULL,
       alias_norm TEXT NOT NULL,
       PRIMARY KEY (note_id, alias)
     )",
    "CREATE TABLE IF NOT EXISTS note_tags (
       note_id  INTEGER NOT NULL REFERENCES notes(id) ON DELETE CASCADE,
       tag      TEXT NOT NULL,
       tag_norm TEXT NOT NULL,
       PRIMARY KEY (note_id, tag)
     )",
    "CREATE TABLE IF NOT EXISTS note_frontmatter_fields (
       note_id    INTEGER NOT NULL REFERENCES notes(id) ON DELETE CASCADE,
       field      TEXT NOT NULL,
       value      TEXT NOT NULL,
       value_type TEXT NOT NULL DEFAULT 'string',
       value_norm TEXT NOT NULL,
       PRIMARY KEY (note_id, field, value)
     )",
    "CREATE TABLE IF NOT EXISTS settings (
       key   TEXT PRIMARY KEY,
       value TEXT NOT NULL
     )",
    "CREATE TABLE IF NOT EXISTS db_meta (
       key   TEXT PRIMARY KEY,
       value TEXT NOT NULL
     )",
    "CREATE TABLE IF NOT EXISTS event_log (
       id        INTEGER PRIMARY KEY,
       action    TEXT NOT NULL,
       path      TEXT NOT NULL,
       timestamp TEXT NOT NULL
     )",
    "CREATE TABLE IF NOT EXISTS llm_cache (
       key           TEXT PRIMARY KEY,
       value         TEXT NOT NULL,
       expires_at_ms INTEGER NOT NULL
     )",
    "CREATE TABLE IF NOT EXISTS vector_metadata (
       chunk_id       INTEGER PRIMARY KEY REFERENCES chunks(id) ON DELETE CASCADE,
       model          TEXT NOT NULL,
       dimensions     INTEGER NOT NULL,
       embedded_at_ms INTEGER NOT NULL
     )",
    "CREATE TABLE IF NOT EXISTS graph_meta (
       key   TEXT PRIMARY KEY,
       value TEXT NOT NULL
     )",
    "CREATE TABLE IF NOT EXISTS graph_nodes (
       vault_path               TEXT PRIMARY KEY,
       title                    TEXT NOT NULL,
       aliases                  TEXT NOT NULL DEFAULT '[]',
       tags                     TEXT NOT NULL DEFAULT '[]',
       scope                    TEXT NOT NULL DEFAULT '',
       note_type                TEXT,
       sources                  TEXT NOT NULL DEFAULT '[]',
       outgoing_degree          INTEGER NOT NULL DEFAULT 0,
       backlink_degree          INTEGER NOT NULL DEFAULT 0,
       total_degree             INTEGER NOT NULL DEFAULT 0,
       structural               INTEGER NOT NULL DEFAULT 0,
       community_id             INTEGER,
       community_cohesion       REAL NOT NULL DEFAULT 0.0,
       community_neighbor_count INTEGER NOT NULL DEFAULT 0,
       bridge_weight            REAL NOT NULL DEFAULT 0.0
     )",
    "CREATE TABLE IF NOT EXISTS graph_edges (
       from_path TEXT NOT NULL,
       to_path   TEXT NOT NULL,
       link_text TEXT NOT NULL DEFAULT '',
       weight    INTEGER NOT NULL DEFAULT 1,
       PRIMARY KEY (from_path, to_path)
     )",
    "CREATE TABLE IF NOT EXISTS graph_sources (
       source TEXT NOT NULL,
       path   TEXT NOT NULL,
       PRIMARY KEY (source, path)
     )",
    "CREATE TABLE IF NOT EXISTS graph_communities (
       community_id INTEGER PRIMARY KEY,
       node_count   INTEGER NOT NULL,
       cohesion     REAL NOT NULL DEFAULT 0.0,
       top_nodes    TEXT NOT NULL DEFAULT '[]'
     )",
    "CREATE TABLE IF NOT EXISTS graph_missing_links (
       path       TEXT NOT NULL,
       target     TEXT NOT NULL,
       term       TEXT NOT NULL,
       line       INTEGER,
       PRIMARY KEY (path, target, term)
     )",
    "CREATE VIRTUAL TABLE IF NOT EXISTS notes_fts_bm25 USING fts5(
       title, aliases, content,
       content='notes', content_rowid='id',
       tokenize = 'unicode61 tokenchars ''+#'''
     )",
    "CREATE VIRTUAL TABLE IF NOT EXISTS notes_fts_fuzzy USING fts5(
       title, aliases,
       content='notes', content_rowid='id',
       tokenize = 'trigram'
     )",
    "CREATE INDEX IF NOT EXISTS idx_links_to ON links(to_path)",
    "CREATE INDEX IF NOT EXISTS idx_chunks_note_chunk_index ON chunks(note_id, chunk_index)",
    "CREATE INDEX IF NOT EXISTS idx_note_aliases_alias_norm ON note_aliases(alias_norm)",
    "CREATE INDEX IF NOT EXISTS idx_note_tags_tag_norm ON note_tags(tag_norm)",
    "CREATE INDEX IF NOT EXISTS idx_fm_field_value_norm ON note_frontmatter_fields(field, value_norm)",
    "CREATE INDEX IF NOT EXISTS idx_fm_field_type_value
     ON note_frontmatter_fields(field, value_type, value)",
    "CREATE INDEX IF NOT EXISTS idx_notes_active_path ON notes(active, vault_path)",
    "CREATE INDEX IF NOT EXISTS idx_notes_active_scope ON notes(active, scope)",
    "CREATE INDEX IF NOT EXISTS idx_links_from ON links(from_path)",
    "CREATE INDEX IF NOT EXISTS idx_graph_edges_to ON graph_edges(to_path)",
    "CREATE INDEX IF NOT EXISTS idx_graph_sources_path ON graph_sources(path)",
    "CREATE INDEX IF NOT EXISTS idx_graph_nodes_community ON graph_nodes(community_id)",
    "CREATE INDEX IF NOT EXISTS idx_graph_missing_links_path ON graph_missing_links(path)",
    "CREATE INDEX IF NOT EXISTS idx_notes_hash ON notes(hash)",
    "CREATE INDEX IF NOT EXISTS idx_notes_docid ON notes(docid)",
    "CREATE INDEX IF NOT EXISTS idx_chunks_hash ON chunks(chunk_hash)",
];

/// FTS5 sync triggers and the seeded `db_version` setting.
pub const TRIGGER_MIGRATIONS: &[&str] = &[
    "CREATE TRIGGER IF NOT EXISTS notes_fts_ai AFTER INSERT ON notes
     WHEN NEW.active = 1
     BEGIN
       INSERT INTO notes_fts_bm25(rowid, title, aliases, content)
       VALUES (NEW.id, NEW.title, NEW.aliases, NEW.content);
       INSERT INTO notes_fts_fuzzy(rowid, title, aliases)
       VALUES (NEW.id, NEW.title, NEW.aliases);
     END",
    "CREATE TRIGGER IF NOT EXISTS notes_fts_au AFTER UPDATE OF title, aliases, content, active ON notes
     BEGIN
       INSERT INTO notes_fts_bm25(notes_fts_bm25, rowid, title, aliases, content)
       VALUES ('delete', OLD.id, OLD.title, OLD.aliases, OLD.content);
       INSERT INTO notes_fts_fuzzy(notes_fts_fuzzy, rowid, title, aliases)
       VALUES ('delete', OLD.id, OLD.title, OLD.aliases);
       INSERT INTO notes_fts_bm25(rowid, title, aliases, content)
       SELECT NEW.id, NEW.title, NEW.aliases, NEW.content
       WHERE NEW.active = 1;
       INSERT INTO notes_fts_fuzzy(rowid, title, aliases)
       SELECT NEW.id, NEW.title, NEW.aliases
       WHERE NEW.active = 1;
     END",
    "CREATE TRIGGER IF NOT EXISTS notes_fts_ad AFTER DELETE ON notes
     BEGIN
       INSERT INTO notes_fts_bm25(notes_fts_bm25, rowid, title, aliases, content)
       VALUES ('delete', OLD.id, OLD.title, OLD.aliases, OLD.content);
       INSERT INTO notes_fts_fuzzy(notes_fts_fuzzy, rowid, title, aliases)
       VALUES ('delete', OLD.id, OLD.title, OLD.aliases);
     END",
    "INSERT OR IGNORE INTO settings(key, value) VALUES ('db_version', '0')",
    "INSERT OR IGNORE INTO db_meta(key, value) VALUES ('db_version', '0')",
];

/// No runtime rebuild statements are part of the current schema initializer.
pub const REBUILD_MIGRATIONS: &[&str] = &[];

/// Applies the current schema to an empty or newly-created database.
///
/// Sets the `WAL`, `busy_timeout`, and `foreign_keys` PRAGMAs, then applies
/// current schema and trigger statements inside a single transaction. This is
/// not a historical migration chain; incompatible development indexes should be
/// deleted and rebuilt.
///
/// # Errors
///
/// Returns [`TalonError::Sqlite`] if any statement fails.
pub fn run_migrations(conn: &mut Connection) -> Result<(), TalonError> {
    conn.pragma_update(None, "journal_mode", "WAL")
        .map_err(|source| TalonError::Sqlite {
            context: "set journal_mode",
            source,
        })?;
    conn.pragma_update(None, "busy_timeout", TALON_SQLITE_BUSY_TIMEOUT_MS)
        .map_err(|source| TalonError::Sqlite {
            context: "set busy_timeout",
            source,
        })?;
    conn.pragma_update(None, "foreign_keys", "ON")
        .map_err(|source| TalonError::Sqlite {
            context: "set foreign_keys",
            source,
        })?;

    let tx = conn.transaction().map_err(|source| TalonError::Sqlite {
        context: "begin schema transaction",
        source,
    })?;
    run_statements(&tx, SCHEMA_MIGRATIONS, "schema migration")?;
    run_statements(&tx, TRIGGER_MIGRATIONS, "trigger migration")?;
    tx.commit().map_err(|source| TalonError::Sqlite {
        context: "commit schema",
        source,
    })?;
    Ok(())
}

/// Reads the current index content version.
///
/// Returns `0` when the metadata table or row is absent.
#[must_use]
pub fn read_db_version(conn: &Connection) -> u64 {
    conn.query_row(
        "SELECT value FROM db_meta WHERE key = ?",
        [DB_VERSION_KEY],
        |row| row.get::<_, String>(0),
    )
    .ok()
    .and_then(|value| value.parse::<u64>().ok())
    .unwrap_or(0)
}

/// Increments the index content version and returns the new value.
///
/// The update is a single `SQLite` upsert, so callers that pass a transaction
/// connection get the bump committed or rolled back with their mutation.
///
/// # Errors
///
/// Returns [`TalonError::Sqlite`] if `SQLite` fails to update the metadata row.
pub fn bump_db_version(conn: &Connection) -> Result<u64, TalonError> {
    conn.execute(
        "INSERT INTO db_meta(key, value) VALUES (?, '1')
         ON CONFLICT(key) DO UPDATE SET value = CAST(CAST(value AS INTEGER) + 1 AS TEXT)",
        [DB_VERSION_KEY],
    )
    .map_err(|source| TalonError::Sqlite {
        context: "bump db version",
        source,
    })?;

    let version = read_db_version(conn);
    conn.execute(
        "INSERT INTO settings(key, value) VALUES (?, ?)
         ON CONFLICT(key) DO UPDATE SET value = excluded.value",
        params![DB_VERSION_KEY, version.to_string()],
    )
    .map_err(|source| TalonError::Sqlite {
        context: "mirror db version setting",
        source,
    })?;
    Ok(version)
}

fn run_statements(
    conn: &Connection,
    statements: &[&str],
    context: &'static str,
) -> Result<(), TalonError> {
    for statement in statements {
        conn.execute_batch(statement)
            .map_err(|source| TalonError::Sqlite { context, source })?;
    }
    Ok(())
}

#[cfg(test)]
#[allow(clippy::unwrap_used, clippy::expect_used)]
mod tests;