package context

import (
	"io"
	"os"
)

// Context interface for handling command-line arguments and standard input/output streams
type Context interface {
	Args() []string    // Get the list of arguments passed to the program
	Stdin() io.Reader  // Get the standard input stream
	Stdout() io.Writer // Get the standard output stream
	Stderr() io.Writer // Get the error output stream
	Exit(int)          // Exit the program with a specific status code
}

type context struct {
	args   []string
	stdin  io.Reader
	stdout io.Writer
	stderr io.Writer
	exit   func(int)
}

func (ctx context) Args() []string    { return ctx.args }
func (ctx context) Stdin() io.Reader  { return ctx.stdin }
func (ctx context) Stdout() io.Writer { return ctx.stdout }
func (ctx context) Stderr() io.Writer { return ctx.stderr }
func (ctx context) Exit(status int)   { ctx.exit(status) }

type Option func(ctx *context)

func WithArgs(args []string) Option {
	return func(ctx *context) { ctx.args = args }
}

func WithStdin(stdin io.Reader) Option {
	return func(ctx *context) { ctx.stdin = stdin }
}

func WithStdout(stdout io.Writer) Option {
	return func(ctx *context) { ctx.stdout = stdout }
}

func WithStderr(stderr io.Writer) Option {
	return func(ctx *context) { ctx.stderr = stderr }
}

func WithExit(exit func(int)) Option {
	return func(ctx *context) { ctx.exit = exit }
}

// New returns a new instance of the Context interface with
// the standard input, output, and error streams.
func New(opts ...Option) Context {
	ctx := &context{
		args:   os.Args[1:], // Skip monkey binary itself
		stdin:  os.Stdin,
		stdout: os.Stdout,
		stderr: os.Stderr,
		exit:   os.Exit,
	}

	for _, opt := range opts {
		opt(ctx)
	}

	return ctx
}