// Copyright © 2019 Ettore Di Giacinto <mudler@gentoo.org>
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, see <http://www.gnu.org/licenses/>.

package gentoo

// NOTE: Look here as an example of the builder definition executor
// https://gist.github.com/adnaan/6ca68c7985c6f851def3

import (
	"context"
	"errors"
	"fmt"
	"os"
	"path/filepath"
	"regexp"
	"strings"

	. "github.com/mudler/luet/pkg/logger"

	pkg "github.com/mudler/luet/pkg/package"
	"mvdan.cc/sh/expand"
	"mvdan.cc/sh/shell"
	"mvdan.cc/sh/syntax"
)

// SimpleEbuildParser ignores USE flags and generates just 1-1 package
type SimpleEbuildParser struct {
	World pkg.PackageDatabase
}

func SourceFile(ctx context.Context, path string) (map[string]expand.Variable, error) {
	f, err := os.Open(path)
	if err != nil {
		return nil, fmt.Errorf("could not open: %v", err)
	}
	defer f.Close()
	file, err := syntax.NewParser(syntax.StopAt("src")).Parse(f, path)
	if err != nil {
		return nil, fmt.Errorf("could not parse: %v", err)
	}
	return shell.SourceNode(ctx, file)
}

// ScanEbuild returns a list of packages (always one with SimpleEbuildParser) decoded from an ebuild.
func (ep *SimpleEbuildParser) ScanEbuild(path string, tree pkg.Tree) ([]pkg.Package, error) {
	defer func() {
		if r := recover(); r != nil {
			Error(r)
		}
	}()
	file := filepath.Base(path)
	file = strings.Replace(file, ".ebuild", "", -1)

	decodepackage, err := regexp.Compile(`^([<>]?\~?=?)((([^\/]+)\/)?(?U)(\S+))(-(\d+(\.\d+)*[a-z]?(_(alpha|beta|pre|rc|p)\d*)*(-r\d+)?))?$`)
	if err != nil {
		return []pkg.Package{}, errors.New("Invalid regex")

	}

	v := strings.Replace(path, filepath.Base(file)+".ebuild", "", -1)

	pName := filepath.Base(v)

	cat := filepath.Base(strings.Replace(v, pName, "", -1))

	packageInfo := decodepackage.FindAllStringSubmatch(filepath.Join(cat, file), -1)
	if len(packageInfo) != 1 || len(packageInfo[0]) != 12 {
		return []pkg.Package{}, errors.New("Failed decoding ebuild: " + path)
	}
	pack := &pkg.DefaultPackage{Name: packageInfo[0][5], Version: packageInfo[0][7], Category: cat}

	vars, err := SourceFile(context.TODO(), path)
	if err != nil {
		return []pkg.Package{pack}, nil
		//	return []pkg.Package{}, err
	}

	// TODO: Handle this a bit better

	rdepend, ok := vars["RDEPEND"]
	if ok {
		rdepends := strings.Split(rdepend.String(), "\n")
		pack.PackageConflicts = []*pkg.DefaultPackage{}
		pack.PackageRequires = []*pkg.DefaultPackage{}
		for _, rr := range rdepends {

			rr = strings.TrimSpace(rr)
			conflicts := false
			if strings.HasPrefix(rr, "~") {
				rr = rr[1:]
			}
			if strings.HasPrefix(rr, "!") {
				rr = rr[1:]
				conflicts = true
			}
			if strings.HasSuffix(rr, "-") {
				rr = rr[0 : len(rr)-1]
			}

			deppackageInfo := decodepackage.FindAllStringSubmatch(rr, -1)
			if len(deppackageInfo) != 1 || len(deppackageInfo[0]) != 12 {
				continue
			}

			//TODO: Resolve to db or create a new one.
			dep := &pkg.DefaultPackage{Name: deppackageInfo[0][5], Version: deppackageInfo[0][7], Category: deppackageInfo[0][4]}
			if conflicts {
				pack.PackageConflicts = append(pack.PackageConflicts, dep)
			} else {
				pack.PackageRequires = append(pack.PackageRequires, dep)
			}
		}

	}

	//TODO: Deps and conflicts
	return []pkg.Package{pack}, nil
}