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

package transport

import (
_	"errors"
	"path/filepath"
	"io"
	"os"
	"net/url"
	"strings"
	"fmt"
	"compress/gzip"
)

type File struct {
	uri *url.URL
	path string
	exttype string
	fileext string
	readHandle *os.File
	writeHandle *os.File
	gzip bool
	gzipWriter io.WriteCloser
	gzipReader io.ReadCloser
}

func NewFile(u *url.URL) (f *File, err error) {
	f = &File {
		uri: u,
		path: filepath.Join(u.Hostname(), u.RequestURI()),
	}
	f.extension()
	f.DetectGzip()

	if f.path == "" || f.path == "-" {
		f.readHandle = os.Stdin
		f.writeHandle = os.Stdout
	} else {
		if f.readHandle, err = os.OpenFile(f.Path(), os.O_RDWR|os.O_CREATE, 0644); err != nil {
			return
		}
		f.writeHandle = f.readHandle
	}

	if f.Gzip() {
		f.gzipWriter = gzip.NewWriter(f.writeHandle)
		if f.gzipReader, err = gzip.NewReader(f.readHandle); err != nil {
			return
		}
	}
	return
}

func (f *File) extension() {
	elements := strings.Split(f.path, ".")
	numberOfElements := len(elements)
	if numberOfElements > 2 {
		f.exttype = elements[numberOfElements - 2]
		f.fileext = elements[numberOfElements - 1]
	}
	f.exttype = elements[numberOfElements - 1]
}

func (f *File) DetectGzip() {
	f.gzip = (f.uri.Query().Get("gzip") == "true" || f.fileext == "gz") 
}

func (f *File) URI() *url.URL {
	return f.uri
}

func (f *File) Path() string {
	return f.path
}

func (f *File) Signature() (documentSignature string) {
	if signatureResp, signatureErr := os.Open(fmt.Sprintf("%s.sig", f.uri.String())); signatureErr == nil {
		defer signatureResp.Close()
		readSignatureBody, readSignatureErr := io.ReadAll(signatureResp)
		if readSignatureErr == nil {
			documentSignature = string(readSignatureBody)
		} else {
			panic(readSignatureErr)
		}
	} else {
		panic(signatureErr)
	}
	return documentSignature
}

func (f *File) ContentType() string {
	return f.exttype
}

func (f *File) SetGzip(gzip bool) {
	f.gzip = gzip
}

func (f *File) Gzip() bool {
	return f.gzip
}

func (f *File) Reader() io.ReadCloser {
	if f.Gzip() {
		return f.gzipReader
	}
	return f.readHandle
}

func (f *File) Writer() io.WriteCloser {
	if f.Gzip() {
		return f.gzipWriter
	}
	return f.writeHandle
}