// Copyright 2024 Matthew Rich <matthewrich.conf@gmail.com>. All rights reserved.

package types

import (
	"errors"
	"fmt"
	"net/url"
	"strings"
	"path/filepath"
	"log/slog"
_	"runtime/debug"
)

/*

The `types` package provides a generic method of registering a type factory.

*/

var (
	ErrUnknownType = errors.New("Unknown type")
	ErrInvalidProduct = errors.New("Invalid product")
)

type Factory[Product comparable] func(*url.URL) Product
type RegistryTypeMap[Product comparable] map[string]Factory[Product]

//type Name[Registry any] string //`json:"type"`

type Types[Product comparable] struct {
	registry RegistryTypeMap[Product]
	contentTypes RegistryTypeMap[Product]
}

func New[Product comparable]() *Types[Product] {
	return &Types[Product]{registry: make(map[string]Factory[Product]), contentTypes: make(map[string]Factory[Product])}
}

func (t *Types[Product]) Register(names []string, factory Factory[Product]) {
	for _,name := range names {
		t.registry[name] = factory
	}
}

func (t *Types[Product]) RegisterContentType(contenttypes []string, factory Factory[Product]) {
	for _,name := range contenttypes {
		t.contentTypes[name] = factory
	}
}

func (t *Types[Product]) FromExtension(path string) (Factory[Product], error) {
	elements := strings.Split(path, ".")
	numberOfElements := len(elements)
	slog.Info("Types[Product].FromExtension()", "path", path, "elements", elements, "types", t.contentTypes, "numberOfElements", numberOfElements)
	if numberOfElements >= 2 {
//	slog.Info("Types[Product].FromExtension()", "path", path, "elements", elements, "types", t.contentTypes, "stacktrace", string(debug.Stack()))
		if numberOfElements > 2 {
			ext := strings.Join(elements[numberOfElements - 2: numberOfElements], ".")
//			slog.Info("Types[Product].FromExtension() - Lookup", "ext", ext, "stacktrace", string(debug.Stack()))
			slog.Info("Types[Product].FromExtension() - Lookup", "ext", ext, "types", t)
			if src := t.GetContentType(ext); src != nil {
				return src, nil
			}
		}
		slog.Info("Types[Product].FromExtension() - Lookup", "ext", elements[numberOfElements - 1], "types", t.contentTypes)
		if src := t.GetContentType(elements[numberOfElements - 1]); src != nil {
			return src, nil
		}
	}
	return nil, fmt.Errorf("%w: %s", ErrUnknownType, path)
}

func (t *Types[Product]) New(uri string) (result Product, err error) {
	u, e := url.Parse(uri)
	if u == nil || e != nil {
		err = fmt.Errorf("%w: %s %s", ErrUnknownType, e, uri)
		return
	}
	return t.NewFromParsedURI(u)
}

func (t *Types[Product]) NewFromParsedURI(u *url.URL) (result Product, err error) {
	if u.Scheme == "" {
		u.Scheme = "file"
	}

	path := filepath.Join(u.Hostname(), u.Path)
	if len(path) > 0 {	
		if d, lookupErr := t.FromExtension(filepath.Base(path)); d != nil {
			return d(u), lookupErr
		} else {
			slog.Info("Types[Product].NewFromParsedURI() - FromExtension()", "uri", u, "path", path, "error", lookupErr) //, "stacktrace", string(debug.Stack()))
		}
	}

	if r, ok := t.registry[u.Scheme]; ok {
		if result = r(u); result != any(nil) {
			return result, nil
		} else {
			return result, fmt.Errorf("%w: factory failed creating %s", ErrInvalidProduct, u.String())
		}
	}
	err = fmt.Errorf("%w: %s", ErrUnknownType, u.Scheme)
	return
}

func (t *Types[Product]) Has(typename string) bool {
	if _, ok := t.registry[typename]; ok {
		return true
	}
	return false
}

func (t *Types[Product]) HasContentType(contenttype string) bool {
	if _, ok := t.contentTypes[contenttype]; ok {
		return true
	}
	return false
}

func (t *Types[Product]) GetContentType(contenttype string) Factory[Product] {
	if d, ok := t.contentTypes[contenttype]; ok {
		return d
	}
	return nil
}

/*
func (n *Name[Registry]) UnmarshalJSON(b []byte) error {
	ProductTypeName := strings.Trim(string(b), "\"")
	if Registry.Has(ProductTypeName) {
		*n = Name[Registry](ProductTypeName)
		return nil
	}
	return fmt.Errorf("%w: %s", ErrUnknownType, ProductTypeName)
}
*/