var ErrShutdown = fmt.Errorf("dispatcher is shutting down")

type Binary struct {
	// The name of the binary.
	// For 	quickjs, this must match the instance import name, "javy_quickjs_provider_v2".
	// For the main module, we only use this for caching.
	Name string

	// THe wasm binary.
	Data []byte
}

type CompileModuleContext struct {
	Opts    Options
	Runtime wazero.Runtime
}

type CompiledModule struct {
	// Runtime (e.g. QuickJS) may be nil if not needed (e.g. embedded in Module).
	Runtime wazero.CompiledModule

	// If Runtime is not nil, this should be the name of the instance.
	RuntimeName string

	// The main module to instantiate.
	// This will be insantiated multiple times in a pool,
	// so it does not need a name.
	Module wazero.CompiledModule
}

type Dispatcher[Q, R any] interface {
	Execute(ctx context.Context, q Message[Q]) (Message[R], error)
	Close() error
}

type Dispatchers struct {
	// contains filtered or unexported fields
}

type Header struct {
	// Major version of the protocol.
	Version uint16 `json:"version"`

	// Unique ID for the request.
	// Note that this only needs to be unique within the current request set time window.
	ID uint32 `json:"id"`

	// Set in the response if there was an error.
	Err string `json:"err"`
}

type KatexInput struct {
	Expression string       `json:"expression"`
	Options    KatexOptions `json:"options"`
}

type KatexOptions struct {
	// html, mathml (default), htmlAndMathml
	Output string `json:"output"`

	// If true, display math in display mode, false in inline mode.
	DisplayMode bool `json:"displayMode"`

	// Render \tags on the left side instead of the right.
	Leqno bool `json:"leqno"`

	// If true,  render flush left with a 2em left margin.
	Fleqn bool `json:"fleqn"`

	// The color used for typesetting errors.
	// A color string given in the format "#XXX" or "#XXXXXX"
	ErrorColor string `json:"errorColor"`

	//  A collection of custom macros.
	Macros map[string]string `json:"macros,omitempty"`

	// Specifies a minimum thickness, in ems, for fraction lines.
	MinRuleThickness float64 `json:"minRuleThickness"`

	// If true, KaTeX will throw a ParseError when it encounters an unsupported command.
	ThrowOnError bool `json:"throwOnError"`
}

type KatexOutput struct {
	Output string `json:"output"`
}

type Message[T any] struct {
	Header Header `json:"header"`
	Data   T      `json:"data"`
}

type Options struct {
	Ctx context.Context

	Infof func(format string, v ...any)

	// E.g. quickjs wasm. May be omitted if not needed.
	Runtime Binary

	// The main module to instantiate.
	Main Binary

	CompilationCacheDir string
	PoolSize            int

	// Memory limit in MiB.
	Memory int
}