vm

type Backend interface {
	// Returns the URI scheme the backend supports.
	Scheme() string
	// Get attempts to retrieve the WASM asset.
	Get(multAddr ma.Multiaddr) (io.ReadCloser, error)
	// Close will close the Backend.
	Close() error
}

type Config struct {
	MemoryLimitPages uint32 // should default to MemoryLimitPages
	Output           OutputType
}

type Context interface {
	// Context returns the go context of the function instance
	Context() context.Context

	// Project returns the Taubyte project id
	Project() string

	// Application returns the application, if none returns an empty string
	Application() string

	// Resource returns the id of the resource being used.
	Resource() string

	// Branch returns the branch name used by this resource execution pipeline.
	Branch() string

	// Commit returns the commit id used by this resource execution pipeline.
	Commit() string

	// Clone clones the VM.Context with a new go context
	Clone(context.Context) Context
}

type ExternType = byte

type Factory interface {
	// Load will initialize the Factory
	Load(hm HostModule) error

	// Close will close and cleanup the Factory
	Close() error

	// Name returns the name of the Factory
	Name() string
}

type Function interface {
	// Definition is metadata about this function from its defining module.
	Definition() FunctionDefinition

	// Call invokes the function with parameters encoded according to ParamTypes. Up to one result is returned.
	Call(ctx context.Context, params ...uint64) ([]uint64, error)
}

type FunctionDefinition interface {
	// Name is the module-defined name of the function, which is not necessarily
	// the same as its export name.
	Name() string

	// ParamTypes are the possibly empty sequence of value types accepted by a
	// function with this signature.
	ParamTypes() []ValueType

	// ResultTypes are the results of the function.
	ResultTypes() []ValueType
}

type FunctionInstance interface {
	FunctionInstanceCommon
	Call(ctx context.Context, args ...interface{}) Return
	RawCall(ctx context.Context, args ...uint64) ([]uint64, error)
}

type FunctionInstanceCommon interface {
	// Cancel will cancel the context of the FunctionInstance
	Cancel() error
}

type Global interface {
	// Type describes the numeric type of the global.
	Type() ValueType

	// Get returns the last known value of this global. When the context is nil, it defaults to context.Background.
	Get() uint64
}

type HostFunction interface{}

type HostModule interface {
	// Functions adds the function definitions to the HostModule
	Functions(...*HostModuleFunctionDefinition) error

	// Memory adds the memory definitions to the HostModule
	Memories(...*HostModuleMemoryDefinition) error

	// Globals adds the global definitions to the HostModule
	Globals(...*HostModuleGlobalDefinition) error

	// Compile will compile the defined HostModule, and return a ModuleInstance
	Compile() (ModuleInstance, error)
}

type HostModuleDefinitions struct {
	Functions []*HostModuleFunctionDefinition
	Memories  []*HostModuleMemoryDefinition
	Globals   []*HostModuleGlobalDefinition
}

type HostModuleFunctionDefinition struct {
	Name    string
	Handler HostFunction
}

type HostModuleGlobalDefinition struct {
	Name  string
	Value interface{}
}

type HostModuleMemoryDefinition struct {
	Name  string
	Pages struct {
		Min   uint64
		Max   uint64
		Maxed bool
	}
}

type Instance interface {
	// Context returns the context of the function Instance
	Context() Context

	// Close will close the Instance
	Close() error

	// Runtime returns a new Function Instance Runtime
	Runtime(*HostModuleDefinitions) (Runtime, error)

	// Filesystem returns the filesystem used by the given Instance.
	Filesystem() afero.Fs

	// Stdout returns the Reader interface of stdout
	Stdout() io.Reader

	// Stderr returns the Reader interface of stderr
	Stderr() io.Reader
}

type Loader interface {
	// Load resolves the module, then loads the module using a Backend
	Load(ctx Context, module string) (io.ReadCloser, error)
}

type Memory interface {
	Size() uint32

	// Grow increases memory by the delta in pages (65536 bytes per page).
	Grow(deltaPages uint32) (previousPages uint32, ok bool)

	// ReadByte reads a single byte from the underlying buffer at the offset or returns false if out of range.
	ReadByte(offset uint32) (byte, bool)

	// ReadUint16Le reads a uint16 in little-endian encoding from the underlying buffer at the offset in or returns
	// false if out of range.
	ReadUint16Le(offset uint32) (uint16, bool)

	// ReadUint32Le reads a uint32 in little-endian encoding from the underlying buffer at the offset in or returns
	// false if out of range.
	ReadUint32Le(offset uint32) (uint32, bool)

	// ReadFloat32Le reads a float32 from 32 IEEE 754 little-endian encoded bits in the underlying buffer at the offset
	// or returns false if out of range.
	ReadFloat32Le(offset uint32) (float32, bool)

	// ReadUint64Le reads a uint64 in little-endian encoding from the underlying buffer at the offset or returns false
	// if out of range.
	ReadUint64Le(offset uint32) (uint64, bool)

	// ReadFloat64Le reads a float64 from 64 IEEE 754 little-endian encoded bits in the underlying buffer at the offset
	// or returns false if out of range.
	ReadFloat64Le(offset uint32) (float64, bool)

	// Read reads byteCount bytes from the underlying buffer at the offset or
	// returns false if out of range.
	Read(offset, byteCount uint32) ([]byte, bool)

	// WriteByte writes a single byte to the underlying buffer at the offset in or returns false if out of range.
	WriteByte(offset uint32, v byte) bool

	// WriteUint16Le writes the value in little-endian encoding to the underlying buffer at the offset in or returns
	// false if out of range.
	WriteUint16Le(offset uint32, v uint16) bool

	// WriteUint32Le writes the value in little-endian encoding to the underlying buffer at the offset in or returns
	// false if out of range.
	WriteUint32Le(offset, v uint32) bool

	// WriteFloat32Le writes the value in 32 IEEE 754 little-endian encoded bits to the underlying buffer at the offset
	// or returns false if out of range.
	WriteFloat32Le(offset uint32, v float32) bool

	// WriteUint64Le writes the value in little-endian encoding to the underlying buffer at the offset in or returns
	// false if out of range.
	WriteUint64Le(offset uint32, v uint64) bool

	// WriteFloat64Le writes the value in 64 IEEE 754 little-endian encoded bits to the underlying buffer at the offset
	// or returns false if out of range.
	WriteFloat64Le(offset uint32, v float64) bool

	// Write writes the slice to the underlying buffer at the offset or returns false if out of range.
	Write(offset uint32, v []byte) bool
}

type MemorySizer func(minPages uint32, maxPages *uint32) (min, capacity, max uint32)

type Module interface {
	// Name is the name this module was instantiated with. Exported functions can be imported with this name.
	Name() string

	// Memory returns a memory defined in this module or nil if there are none wasn't.
	Memory() Memory

	// ExportedFunction returns a function exported from this module or nil if it wasn't.
	ExportedFunction(name string) Function

	// ExportedMemory returns a memory exported from this module or nil if it wasn't.
	ExportedMemory(name string) Memory

	// ExportedGlobal a global exported from this module or nil if it wasn't.
	ExportedGlobal(name string) Global

	// CloseWithExitCode releases resources allocated for this Module. Use a non-zero exitCode parameter to indicate a
	// failure to ExportedFunction callers. When the context is nil, it defaults to context.Background.
	CloseWithExitCode(exitCode uint32) error

	// Close closes the resource. When the context is nil, it defaults to context.Background.
	Close(context.Context) error
}

type ModuleInstance interface {
	// Function returns a FunctionInstance of given name from the ModuleInstance
	Functions() []FunctionDefinition
	Function(name string) (FunctionInstance, error)
	Memory() Memory
}

type MutableGlobal interface {
	Global

	// Set updates the value of this global. When the context is nil, it defaults to context.Background.
	Set(v uint64)
}

type OutputType uint32

type Plugin interface {
	// New creates a new PluginInstance
	New(Instance) (PluginInstance, error)

	// Name returns the name of the Plugin
	Name() string

	Close() error
}

type PluginInstance interface {
	// Load will load all Factories to the HostModule, and return the ModuleInstance
	Load(HostModule) (ModuleInstance, error)

	// Close will close the PluginInstance
	Close() error
}

type Resolver interface {
	// Lookup resolves a module name and returns the uri
	Lookup(ctx Context, module string) (ma.Multiaddr, error)
}

type Return interface {
	// Returns an error
	Error() error

	// Rets will returns the raw uint64 values of the call return
	Rets() []uint64

	// Reflect assigns the return values to the given args
	Reflect(args ...interface{}) error
}

type Runtime interface {
	Module(name string) (ModuleInstance, error)
	Expose(name string) (HostModule, error)
	Attach(plugin Plugin) (PluginInstance, ModuleInstance, error)
	Stdout() io.Reader
	Stderr() io.Reader
	// TODO: Add Runtime Stat
	Close() error
}

type Service interface {
	New(context Context, config Config) (Instance, error)
	Source() Source
	Close() error
}

type Source interface {
	// Module Loads the given module name, and returns the SourceModule
	Module(ctx Context, name string) (SourceModule, error)
}

type SourceModule []byte

type ValueType = byte