package module

import (
	"bytes"
	"embed"
	"errors"
	"fmt"
	"image"
	"image/jpeg"
	"image/png"
	"path"
	"strings"

	"github.com/dop251/goja"
	"github.com/dop251/goja_nodejs/require"
	"tangled.org/cdbrdr.com/scrn/internal/transform"
)

var (
	ErrImgSrcUnknown = errors.New("img src unknown")
)

//go:generate esbuild scrn/*.jsx --jsx=automatic --jsx-factory=h --jsx-fragment=b --jsx-import-source=react --format=cjs --minify --outdir=scrn
//go:generate esbuild jsx/jsx-runtime.js --outfile=jsx/jsx-runtime.min.js --format=cjs --minify

//go:embed scrn/* jsx/*
var f embed.FS

func LoadImgSrc(p string) (image.Image, error) {
	content, err := f.ReadFile(p)
	if err != nil {
		return nil, err
	}

	if strings.HasSuffix(p, ".png") {
		img, err := png.Decode(bytes.NewBuffer(content))
		if err != nil {
			return nil, err
		}

		return img, nil
	} else if strings.HasSuffix(p, ".jpg") {
		img, err := jpeg.Decode(bytes.NewBuffer(content))
		if err != nil {
			return nil, err
		}

		return img, nil
	}

	return nil, ErrImgSrcUnknown
}

func LoadModule(p string) ([]byte, error) {
	ext := path.Ext(p)

	tryPaths := []string{}
	if ext == "" {
		tryPaths = append(tryPaths, fmt.Sprintf("%s.js", p))
		tryPaths = append(tryPaths, fmt.Sprintf("%s.jsx", p))
	}

	if len(tryPaths) == 0 {
		tryPaths = append(tryPaths, p)
	}

	for _, pth := range tryPaths {
		content, err := f.ReadFile(pth)
		if err != nil {
			continue
		}

		if strings.HasSuffix(pth, ".jsx") {
			code, errs := transform.Transform(path.Base(pth), string(content), transform.FormatCommonJS)
			if len(errs) > 0 {
				continue
			}

			return code, nil
		} else {
			return content, nil
		}
	}

	return nil, require.ModuleFileDoesNotExistError
}

func LoadJSXRuntime() ([]byte, error) {
	// First try pre-transformed
	if code, err := f.ReadFile("jsx/jsx-runtime.min.js"); err == nil {
		return code, nil
	}

	// Then load original source and transform it
	content, err := f.ReadFile("jsx/jsx-runtime.js")
	if err != nil {
		return nil, require.ModuleFileDoesNotExistError
	}

	code, errs := transform.Transform("jsx-runtime.js", string(content), transform.FormatCommonJS)
	if len(errs) > 0 {
		return nil, require.ModuleFileDoesNotExistError
	}

	return code, nil
}

func Enable(runtime *goja.Runtime) *require.RequireModule {
	registry := require.NewRegistryWithLoader(func(p string) ([]byte, error) {
		if strings.HasSuffix(p, "node_modules/react/jsx-runtime") {
			return LoadJSXRuntime()
		}
		if strings.HasPrefix(p, "node_modules/scrn/") {
			return LoadModule(strings.TrimPrefix(p, "node_modules/"))
		}

		return nil, require.ModuleFileDoesNotExistError
	})

	return registry.Enable(runtime)
}