package gitpb

// does processing on the go.mod and go.sum files

import (
	"bufio"
	"errors"
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"go.wit.com/lib/gui/shell"
	"go.wit.com/log"
)

// reads and parses the go.sum file
// does not change anything
func (repo *Repo) ParseGoSum() bool {
	// empty out what was there before
	repo.GoDeps = nil

	// check of the repo is a primitive
	// that means, there is not a go.sum file
	// because the package is completely self contained!
	if err := repo.setPrimitive(); err != nil {
		// temporarily enabled this. this is really noisy
		// log.Info("gitpb.ParseGoSum()", err)
		return false
	}
	if repo.GetGoPrimitive() {
		// log.Info("This repo is primitive!")
		return true
	}
	tmp := filepath.Join(repo.FullPath, "go.sum")
	gosum, err := os.Open(tmp)
	defer gosum.Close()
	if err != nil {
		log.Info("gitpb.ParseGoSum() missing go.sum. Some error happened with go mod init & tidy", err)
		return false
	}

	scanner := bufio.NewScanner(gosum)
	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())

		parts := strings.Split(line, " ")
		if len(parts) == 3 {
			godep := strings.TrimSpace(parts[0])
			version := strings.TrimSpace(parts[1])
			if strings.HasSuffix(version, "/go.mod") {
				version = strings.TrimSuffix(version, "/go.mod")
			}
			new1 := GoDep{
				GoPath:  godep,
				Version: version,
			}
			if repo.GoDeps == nil {
				repo.GoDeps = new(GoDeps)
			}
			repo.GoDeps.AppendByGoPath(&new1)
		} else {
			log.Info("gitpb.ParseGoSum() go.sum parse error invalid:", line)
			return false
		}
	}

	if err := scanner.Err(); err != nil {
		repo.GoDeps = nil
		log.Info("gitpb.ParseGoSum()", err)
		return false
	}
	return true
}

// attempt to parse go.* files in a directory
func GoSumParseDir(moddir string) (*GoDeps, error) {
	isprim, err := computePrimitiveNew(moddir)
	if err != nil {
		// "go mod init" failed
		return nil, err
	}
	if isprim {
		// might be a GO primitive. no go.sum file
		return nil, nil
	}
	// go.sum exists. parse the go.sum file
	return parseGoSumNew(moddir)
}

// Detect a 'Primitive' package. Sets the isPrimitive flag
// will return true if the repo is truly not dependent on _anything_ else
// like spew or lib/widget
// it assumes 'go mod init' and 'go mod tidy' ran without error
func computePrimitiveNew(moddir string) (bool, error) {
	// go mod init & go mod tidy ran without errors
	log.Log(INFO, "isPrimitiveGoMod()", moddir)
	gomod, err := os.Open(filepath.Join(moddir, "go.mod"))
	if err != nil {
		log.Log(INFO, "missing go.mod", moddir)
		return false, err
	}
	defer gomod.Close()

	if shell.Exists(filepath.Join(moddir, "go.sum")) {
		return false, nil
	}

	scanner := bufio.NewScanner(gomod)
	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())

		parts := strings.Fields(line)
		log.Log(INFO, "  gomod:", parts)
		if len(parts) >= 1 {
			log.Log(INFO, "  gomod: part[0] =", parts[0])
			if parts[0] == "require" {
				log.Log(INFO, "  should return false here")
				return false, errors.New("go.mod file is not primitive")
			}
			/*
				if parts[0] == "go" {
					if parts[1] != "1.21" {
						log.Log(WARN, "go not set to 1.21 for", repo.GetGoPath())
						// return false, errors.New("go not set to 1.21 for " + repo.GetGoPath())
					}
				}
			*/
		}
	}
	return true, nil
}

func parseGoSumNew(moddir string) (*GoDeps, error) {
	godeps := new(GoDeps)

	tmp, err := os.Open(filepath.Join(moddir, "go.sum"))
	defer tmp.Close()
	if err != nil {
		log.Info("gitpb.ParseGoSum() missing go.sum. Some error happened with go mod init & tidy", err)
		return nil, err
	}

	scanner := bufio.NewScanner(tmp)
	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())

		parts := strings.Split(line, " ")
		if len(parts) == 3 {
			godep := strings.TrimSpace(parts[0])
			version := strings.TrimSpace(parts[1])
			if strings.HasSuffix(version, "/go.mod") {
				version = strings.TrimSuffix(version, "/go.mod")
			}
			new1 := GoDep{
				GoPath:  godep,
				Version: version,
			}
			godeps.AppendByGoPath(&new1)
		} else {
			return nil, fmt.Errorf("gitpb.ParseGoSum() go.sum parse error invalid: %s", line)
		}
	}

	if err := scanner.Err(); err != nil {
		godeps = nil
		return nil, err
	}
	return godeps, nil
}

func (repo *Repo) GoSumFromPkgDir() (*GoDeps, error) {
	homedir, err := os.UserHomeDir()
	if err != nil {
		return nil, err
	}
	rver := repo.GetLastTag()
	if rver == "" {
		return nil, errors.New("could not get master version")
	}
	goget := repo.GetGoPath() + "@" + rver
	moddir := filepath.Join(homedir, "go/pkg/mod", repo.GetGoPath()+"@"+rver)

	if !shell.IsDir(moddir) {
		cmd := []string{"go", "get", goget}
		repo.RunVerboseOnError(cmd)
	}

	if !shell.IsDir(moddir) {
		return nil, errors.New("missing go/pkg/mod. Run: go get " + goget)
	}
	return GoSumParseDir(moddir)
}

func (repo *Repo) GoSumFromRepo() (*GoDeps, error) {
	return GoSumParseDir(repo.GetFullPath())
}