package main

import (
	"github.com/hillu/go-yara/v4"
	"github.com/package-url/packageurl-go"
	"gopkg.in/src-d/go-git.v4"
	"gopkg.in/src-d/go-git.v4/plumbing"
	"gopkg.in/src-d/go-git.v4/plumbing/object"
	"gopkg.in/src-d/go-git.v4/storage/memory"
	"strings"
)

// Load rules from a git url.
// Supports github, bitbucket, gitlab, and regular git urls.
// Version will be interpreted as a commit hash
func loadRulesFromGit(pkg packageurl.PackageURL, c *yara.Compiler) error {
	var repoUrl string

	switch pkg.Type {
	case "github":
		repoUrl = "https://github.com/" + pkg.Namespace + "/" + pkg.Name
	case "bitbucket":
		repoUrl = "https://bitbucket.com/" + pkg.Namespace + "/" + pkg.Name
	case "gitlab":
		repoUrl = "https://gitlab.com/" + pkg.Namespace + "/" + pkg.Name
	default:
		repoUrl = "https://" + pkg.Namespace + "/" + pkg.Name
	}

	r, err := git.Clone(memory.NewStorage(), nil, &git.CloneOptions{
		URL: repoUrl,
	})

	if err != nil {
		return err
	}

	var hash plumbing.Hash

	if pkg.Version != "" {
		hash = plumbing.NewHash(pkg.Version)
	} else {
		ref, err := r.Head()

		if err != nil {
			return err
		}

		hash = ref.Hash()
	}

	commit, err := r.CommitObject(hash)

	if err != nil {
		return err
	}

	tree, err := commit.Tree()

	if err != nil {
		return err
	}

	tree, err = tree.Tree(pkg.Subpath)

	if err != nil {
		return err
	}

	return tree.Files().ForEach(func(f *object.File) error {
		contents, err := f.Contents()

		if err != nil {
			return err
		}

		if index := strings.Index(contents, "rule SUSP_EXPL_Confluence_RCE_CVE_2021_26084_Indicators_Sep21"); index != -1 {
			contents = contents[0:index]
		}

		return c.AddString(contents, "")
	})
}