overdrive-db 2.3.5

//! OverDrive-DB Rust SDK v1.0.0
//!
//! Zero-config embedded document database with SQL, MVCC transactions,
//! and 6 storage engines.
//!
//! # Quick Start
//! ```rust,no_run
//! use overdrive::OverdriveDb;
//! use serde_json::json;
//!
//! let mut odb = OverdriveDb::open("app.odb").unwrap();
//! odb.create_table("users").unwrap();
//! let id = odb.insert("users", &json!({"name":"Alice","age":30})).unwrap();
//! let doc = odb.get("users", &id).unwrap();
//! println!("{}", doc.unwrap());
//! odb.close().unwrap();
//! ```

pub mod ffi;
pub mod error;

pub use error::{Result, SdkError};

use std::os::raw::c_char;
use serde_json::Value;
use libloading::Symbol;

/// MVCC transaction isolation levels.
#[derive(Debug, Clone, Copy)]
pub enum IsolationLevel {
    ReadUncommitted = 0,
    ReadCommitted   = 1,
    RepeatableRead  = 2,
    Serializable    = 3,
}

/// A live MVCC transaction handle.
pub struct Transaction {
    pub id: u64,
}

/// Options for opening a database.
#[derive(Default)]
pub struct OpenOptions {
    pub password: Option<String>,
    pub engine:   Option<String>,
    pub auto_create_tables: bool,
}

impl OpenOptions {
    pub fn new() -> Self { Self { auto_create_tables: true, ..Default::default() } }
    pub fn password(mut self, p: &str) -> Self { self.password = Some(p.into()); self }
    pub fn engine(mut self, e: &str)   -> Self { self.engine   = Some(e.into()); self }
}

// ── Internal helper ──────────────────────────────────────────────────────────

fn last_error() -> String {
    unsafe {
        let lib = ffi::load();
        let func: Symbol<unsafe extern "C" fn() -> *const c_char> =
            lib.get(b"overdrive_last_error").unwrap();
        let ptr = func();
        ffi::read_static(ptr)
    }
}

// ── Main struct ───────────────────────────────────────────────────────────────

/// OverDrive-DB embedded database handle.
///
/// All operations use `odb` as the idiomatic instance name:
/// ```rust,no_run
/// let mut odb = OverdriveDb::open("app.odb").unwrap();
/// odb.insert("users", &serde_json::json!({"name":"Alice"})).unwrap();
/// ```
pub struct OverdriveDb {
    handle: *mut std::ffi::c_void,
}

unsafe impl Send for OverdriveDb {}

impl Drop for OverdriveDb {
    fn drop(&mut self) {
        if !self.handle.is_null() {
            unsafe {
                let lib = ffi::load();
                let func: Symbol<unsafe extern "C" fn(*mut std::ffi::c_void)> =
                    lib.get(b"overdrive_close").unwrap();
                func(self.handle);
            }
            self.handle = std::ptr::null_mut();
        }
    }
}

impl OverdriveDb {
    // ── Lifecycle ─────────────────────────────────────────────────────────

    /// Open or create a database at `path`.
    pub fn open(path: &str) -> Result<Self> {
        let c_path = ffi::to_cstr(path);
        unsafe {
            let lib = ffi::load();
            let func: Symbol<unsafe extern "C" fn(*const c_char) -> *mut std::ffi::c_void> =
                lib.get(b"overdrive_open").unwrap();
            let handle = func(c_path.as_ptr());
            if handle.is_null() {
                return Err(SdkError(last_error()));
            }
            Ok(Self { handle })
        }
    }

    /// Open with engine and/or password options.
    pub fn open_with_options(path: &str, opts: OpenOptions) -> Result<Self> {
        let c_path   = ffi::to_cstr(path);
        let engine   = opts.engine.as_deref().unwrap_or("Disk");
        let c_engine = ffi::to_cstr(engine);
        let options  = serde_json::json!({
            "password":           opts.password,
            "auto_create_tables": opts.auto_create_tables,
        });
        let c_opts = ffi::to_cstr(&options.to_string());
        unsafe {
            let lib = ffi::load();
            let func: Symbol<unsafe extern "C" fn(*const c_char, *const c_char, *const c_char) -> *mut std::ffi::c_void> =
                lib.get(b"overdrive_open_with_engine").unwrap();
            let handle = func(c_path.as_ptr(), c_engine.as_ptr(), c_opts.as_ptr());
            if handle.is_null() {
                return Err(SdkError(last_error()));
            }
            Ok(Self { handle })
        }
    }

    /// Flush all pending writes to disk.
    pub fn sync(&self) -> Result<()> {
        unsafe {
            let lib = ffi::load();
            let func: Symbol<unsafe extern "C" fn(*mut std::ffi::c_void)> =
                lib.get(b"overdrive_sync").unwrap();
            func(self.handle);
        }
        Ok(())
    }

    /// Close the database explicitly (also called on Drop).
    pub fn close(mut self) -> Result<()> {
        unsafe {
            let lib = ffi::load();
            let func: Symbol<unsafe extern "C" fn(*mut std::ffi::c_void)> =
                lib.get(b"overdrive_close").unwrap();
            func(self.handle);
            self.handle = std::ptr::null_mut();
        }
        Ok(())
    }

    /// Return the native library version string.
    pub fn version() -> String {
        unsafe {
            let lib = ffi::load();
            let func: Symbol<unsafe extern "C" fn() -> *const c_char> =
                lib.get(b"overdrive_version").unwrap();
            ffi::read_static(func())
        }
    }

    // ── Tables ────────────────────────────────────────────────────────────

    /// Create a table.
    pub fn create_table(&mut self, name: &str) -> Result<()> {
        let c_name = ffi::to_cstr(name);
        unsafe {
            let lib = ffi::load();
            let func: Symbol<unsafe extern "C" fn(*mut std::ffi::c_void, *const c_char) -> i32> =
                lib.get(b"overdrive_create_table").unwrap();
            if func(self.handle, c_name.as_ptr()) != 0 {
                return Err(SdkError(last_error()));
            }
        }
        Ok(())
    }

    /// Drop a table.
    pub fn drop_table(&mut self, name: &str) -> Result<()> {
        let c_name = ffi::to_cstr(name);
        unsafe {
            let lib = ffi::load();
            let func: Symbol<unsafe extern "C" fn(*mut std::ffi::c_void, *const c_char) -> i32> =
                lib.get(b"overdrive_drop_table").unwrap();
            if func(self.handle, c_name.as_ptr()) != 0 {
                return Err(SdkError(last_error()));
            }
        }
        Ok(())
    }

    /// List all tables.
    pub fn list_tables(&self) -> Result<Vec<String>> {
        unsafe {
            let lib = ffi::load();
            let func: Symbol<unsafe extern "C" fn(*mut std::ffi::c_void) -> *mut c_char> =
                lib.get(b"overdrive_list_tables").unwrap();
            let ptr = func(self.handle);
            if ptr.is_null() { return Err(SdkError(last_error())); }
            let s = ffi::read_and_free(ptr);
            Ok(serde_json::from_str(&s)?)
        }
    }

    /// Check if a table exists.
    pub fn table_exists(&self, name: &str) -> Result<bool> {
        let c_name = ffi::to_cstr(name);
        unsafe {
            let lib = ffi::load();
            let func: Symbol<unsafe extern "C" fn(*mut std::ffi::c_void, *const c_char) -> i32> =
                lib.get(b"overdrive_table_exists").unwrap();
            Ok(func(self.handle, c_name.as_ptr()) == 1)
        }
    }

    // ── CRUD ─────────────────────────────────────────────────────────────

    /// Insert a JSON document. Returns the generated `_id`.
    pub fn insert(&mut self, table: &str, doc: &Value) -> Result<String> {
        let c_table = ffi::to_cstr(table);
        let c_json  = ffi::to_cstr(&doc.to_string());
        unsafe {
            let lib = ffi::load();
            let func: Symbol<unsafe extern "C" fn(*mut std::ffi::c_void, *const c_char, *const c_char) -> *mut c_char> =
                lib.get(b"overdrive_insert").unwrap();
            let ptr = func(self.handle, c_table.as_ptr(), c_json.as_ptr());
            if ptr.is_null() { return Err(SdkError(last_error())); }
            Ok(ffi::read_and_free(ptr))
        }
    }

    /// Insert multiple documents. Returns a Vec of generated `_id`s.
    pub fn insert_batch(&mut self, table: &str, docs: &[Value]) -> Result<Vec<String>> {
        docs.iter().map(|doc| self.insert(table, doc)).collect()
    }

    /// Get a document by `_id`. Returns `None` if not found.
    pub fn get(&self, table: &str, id: &str) -> Result<Option<Value>> {
        let c_table = ffi::to_cstr(table);
        let c_id    = ffi::to_cstr(id);
        unsafe {
            let lib = ffi::load();
            let func: Symbol<unsafe extern "C" fn(*mut std::ffi::c_void, *const c_char, *const c_char) -> *mut c_char> =
                lib.get(b"overdrive_get").unwrap();
            let ptr = func(self.handle, c_table.as_ptr(), c_id.as_ptr());
            if ptr.is_null() { return Ok(None); }
            let s = ffi::read_and_free(ptr);
            Ok(Some(serde_json::from_str(&s)?))
        }
    }

    /// Update a document by `_id`. Returns `true` if updated.
    pub fn update(&mut self, table: &str, id: &str, patch: &Value) -> Result<bool> {
        let c_table = ffi::to_cstr(table);
        let c_id    = ffi::to_cstr(id);
        let c_json  = ffi::to_cstr(&patch.to_string());
        unsafe {
            let lib = ffi::load();
            let func: Symbol<unsafe extern "C" fn(*mut std::ffi::c_void, *const c_char, *const c_char, *const c_char) -> i32> =
                lib.get(b"overdrive_update").unwrap();
            match func(self.handle, c_table.as_ptr(), c_id.as_ptr(), c_json.as_ptr()) {
                1  => Ok(true),
                0  => Ok(false),
                _  => Err(SdkError(last_error())),
            }
        }
    }

    /// Delete a document by `_id`. Returns `true` if deleted.
    pub fn delete(&mut self, table: &str, id: &str) -> Result<bool> {
        let c_table = ffi::to_cstr(table);
        let c_id    = ffi::to_cstr(id);
        unsafe {
            let lib = ffi::load();
            let func: Symbol<unsafe extern "C" fn(*mut std::ffi::c_void, *const c_char, *const c_char) -> i32> =
                lib.get(b"overdrive_delete").unwrap();
            match func(self.handle, c_table.as_ptr(), c_id.as_ptr()) {
                1 => Ok(true),
                0 => Ok(false),
                _ => Err(SdkError(last_error())),
            }
        }
    }

    /// Count documents in a table.
    pub fn count(&self, table: &str) -> Result<usize> {
        let c_table = ffi::to_cstr(table);
        unsafe {
            let lib = ffi::load();
            let func: Symbol<unsafe extern "C" fn(*mut std::ffi::c_void, *const c_char) -> i32> =
                lib.get(b"overdrive_count").unwrap();
            let n = func(self.handle, c_table.as_ptr());
            if n < 0 { return Err(SdkError(last_error())); }
            Ok(n as usize)
        }
    }

    // ── Query ─────────────────────────────────────────────────────────────

    /// Execute a SQL query. Returns rows as a Vec of JSON Values.
    pub fn query(&mut self, sql: &str) -> Result<Vec<Value>> {
        let c_sql = ffi::to_cstr(sql);
        unsafe {
            let lib = ffi::load();
            let func: Symbol<unsafe extern "C" fn(*mut std::ffi::c_void, *const c_char) -> *mut c_char> =
                lib.get(b"overdrive_query").unwrap();
            let ptr = func(self.handle, c_sql.as_ptr());
            if ptr.is_null() { return Err(SdkError(last_error())); }
            let s = ffi::read_and_free(ptr);
            let v: Value = serde_json::from_str(&s)?;
            // Response: {"rows":[...], "ok": true}  or  {"result":"...", "ok": true}
            if let Some(rows) = v.get("rows").and_then(|r| r.as_array()) {
                return Ok(rows.clone());
            }
            Ok(vec![v])
        }
    }

    /// Full-text search across a table.
    pub fn search(&self, table: &str, text: &str) -> Result<Vec<Value>> {
        let c_table = ffi::to_cstr(table);
        let c_text  = ffi::to_cstr(text);
        unsafe {
            let lib = ffi::load();
            let func: Symbol<unsafe extern "C" fn(*mut std::ffi::c_void, *const c_char, *const c_char) -> *mut c_char> =
                lib.get(b"overdrive_search").unwrap();
            let ptr = func(self.handle, c_table.as_ptr(), c_text.as_ptr());
            if ptr.is_null() { return Ok(vec![]); }
            let s = ffi::read_and_free(ptr);
            Ok(serde_json::from_str(&s).unwrap_or_default())
        }
    }

    // ── Transactions ─────────────────────────────────────────────────────

    /// Begin an MVCC transaction.
    pub fn begin_transaction(&mut self, iso: IsolationLevel) -> Result<Transaction> {
        unsafe {
            let lib = ffi::load();
            let func: Symbol<unsafe extern "C" fn(*mut std::ffi::c_void, i32) -> u64> =
                lib.get(b"overdrive_begin_transaction").unwrap();
            let id = func(self.handle, iso as i32);
            if id == 0 { return Err(SdkError(last_error())); }
            Ok(Transaction { id })
        }
    }

    /// Commit a transaction.
    pub fn commit_transaction(&mut self, txn: &Transaction) -> Result<()> {
        unsafe {
            let lib = ffi::load();
            let func: Symbol<unsafe extern "C" fn(*mut std::ffi::c_void, u64) -> i32> =
                lib.get(b"overdrive_commit_transaction").unwrap();
            if func(self.handle, txn.id) != 0 {
                return Err(SdkError(last_error()));
            }
        }
        Ok(())
    }

    /// Abort (rollback) a transaction.
    pub fn abort_transaction(&mut self, txn: &Transaction) -> Result<()> {
        unsafe {
            let lib = ffi::load();
            let func: Symbol<unsafe extern "C" fn(*mut std::ffi::c_void, u64) -> i32> =
                lib.get(b"overdrive_abort_transaction").unwrap();
            if func(self.handle, txn.id) != 0 {
                return Err(SdkError(last_error()));
            }
        }
        Ok(())
    }

    /// Run a closure inside a transaction — auto commits on Ok, aborts on Err.
    pub fn transaction<F, T>(&mut self, iso: IsolationLevel, f: F) -> Result<T>
    where F: FnOnce(&mut Self) -> Result<T>
    {
        let txn = self.begin_transaction(iso)?;
        match f(self) {
            Ok(v)  => { self.commit_transaction(&txn)?; Ok(v) }
            Err(e) => { let _ = self.abort_transaction(&txn); Err(e) }
        }
    }

    // ── Integrity ─────────────────────────────────────────────────────────

    /// Run an integrity check. Returns a JSON report.
    pub fn verify_integrity(&self) -> Result<Value> {
        unsafe {
            let lib = ffi::load();
            let func: Symbol<unsafe extern "C" fn(*mut std::ffi::c_void) -> *mut c_char> =
                lib.get(b"overdrive_verify_integrity").unwrap();
            let ptr = func(self.handle);
            if ptr.is_null() { return Err(SdkError(last_error())); }
            let s = ffi::read_and_free(ptr);
            Ok(serde_json::from_str(&s)?)
        }
    }
}