package main

import (
	"fmt"
	"io"
	"os"

	"github.com/dop251/goja"
	"github.com/evanw/esbuild/pkg/api"
)

func executeTypeScript(filePath string, stdout, stderr io.Writer) error {
	tsContent, err := os.ReadFile(filePath)
	if err != nil {
		_, _ = fmt.Fprintf(stderr, "Error reading file: %v\n", err)
		return err
	}

	result := api.Transform(string(tsContent), api.TransformOptions{
		Loader:      api.LoaderTS,
		Target:      api.ES2020,
		Format:      api.FormatIIFE,
		Sourcemap:   api.SourceMapNone,
		TreeShaking: api.TreeShakingFalse,
	})

	if len(result.Errors) > 0 {
		_, _ = fmt.Fprintf(stderr, "Transpilation errors:\n")
		for _, err := range result.Errors {
			_, _ = fmt.Fprintf(stderr, "  %s\n", err.Text)
		}
		return fmt.Errorf("transpilation failed")
	}

	vm := goja.New()

	RegisterBuiltins(vm)

	console := vm.NewObject()
	_ = vm.Set("console", console)

	_ = console.Set("log", func(call goja.FunctionCall) goja.Value {
		args := call.Arguments
		for i, arg := range args {
			if i > 0 {
				_, _ = fmt.Fprint(stdout, " ")
			}
			_, _ = fmt.Fprint(stdout, arg.String())
		}
		_, _ = fmt.Fprintln(stdout)
		return goja.Undefined()
	})

	_, err = vm.RunString(string(result.Code))
	if err != nil {
		_, _ = fmt.Fprintf(stderr, "Execution error: %v\n", err)
		return err
	}

	return nil
}

func executeTypeScriptContent(tsContent string, stdout, stderr io.Writer) error {
	result := api.Transform(tsContent, api.TransformOptions{
		Loader:      api.LoaderTS,
		Target:      api.ES2020,
		Format:      api.FormatIIFE,
		Sourcemap:   api.SourceMapNone,
		TreeShaking: api.TreeShakingFalse,
	})

	if len(result.Errors) > 0 {
		_, _ = fmt.Fprintf(stderr, "Transpilation errors:\n")
		for _, err := range result.Errors {
			_, _ = fmt.Fprintf(stderr, "  %s\n", err.Text)
		}
		return fmt.Errorf("transpilation failed")
	}

	vm := goja.New()

	RegisterBuiltins(vm)

	console := vm.NewObject()
	_ = vm.Set("console", console)

	_ = console.Set("log", func(call goja.FunctionCall) goja.Value {
		args := call.Arguments
		for i, arg := range args {
			if i > 0 {
				_, _ = fmt.Fprint(stdout, " ")
			}
			_, _ = fmt.Fprint(stdout, arg.String())
		}
		_, _ = fmt.Fprintln(stdout)
		return goja.Undefined()
	})

	_, err := vm.RunString(string(result.Code))
	if err != nil {
		_, _ = fmt.Fprintf(stderr, "Execution error: %v\n", err)
		return err
	}

	return nil
}

func main() {
	if len(os.Args) < 2 {
		fmt.Fprintln(os.Stderr, "Usage: program <typescript-file>")
		os.Exit(1)
	}

	filePath := os.Args[1]

	if err := executeTypeScript(filePath, os.Stdout, os.Stderr); err != nil {
		os.Exit(1)
	}
}