const Config = @import("./config.zig").Config;

/// Compilation environment and configuration.
///
/// An engine is typically global in a program and contains all the
/// configuration necessary for compiling wasm code. From an engine you'll
/// typically create a `Store`. Engines are created with `initDefault` or
/// `initWithConfig`.
///
/// An engine is safe to share between threads. Multiple stores can be created
/// within the same engine with each store living on a separate thread.
/// Typically you'll create one `Engine` for the lifetime of your program.
///
/// Engines are reference counted internally so `deinit` can be called at any
/// time after a `Store` has been created from one.
pub const Engine = opaque {
    /// Creates a new engine with the default configuration.
    ///
    /// The object returned is owned by the caller and will need to be deleted
    /// with `deinit`. This may return `error.ModuleInit` if the engine could
    /// not be allocated.
    pub fn initDefault() !*Engine {
        return wasm_engine_new() orelse error.ModuleInit;
    }

    /// Creates a new engine with the specified configuration.
    ///
    /// This function will take ownership of the configuration specified
    /// regardless of the outcome of this function. You do not need to call
    /// `Config.deinit` on the argument. The object returned is owned by the
    /// caller and will need to be deleted with `deinit`. This may return
    /// `error.ModuleInit` if the engine could not be allocated.
    pub fn initWithConfig(config: *Config) !*Engine {
        return wasm_engine_new_with_config(config) orelse error.ModuleInit;
    }

    pub fn deinit(self: *Engine) void {
        wasm_engine_delete(self);
    }

    /// Increments the engine-local epoch variable.
    ///
    /// This function will increment the engine's current epoch which can be
    /// used to force WebAssembly code to trap if the current epoch goes
    /// beyond the `Store` configured epoch deadline.
    ///
    /// This function is safe to call from any thread, and it is also
    /// async-signal-safe.
    ///
    /// See also `Config.epoch_interruption_set`.
    pub fn increment_epoch(self: *Engine) void {
        wasmtime_engine_increment_epoch(self);
    }

    extern "c" fn wasm_engine_new() ?*Engine;
    extern "c" fn wasm_engine_new_with_config(*Config) ?*Engine;
    extern "c" fn wasm_engine_delete(*Engine) void;

    extern "c" fn wasmtime_engine_increment_epoch(*Engine) void;
};