package forgepb

import (
	"errors"
	"io/ioutil"
	"net/http"
	"os"
	"path/filepath"
	"strings"

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

// TODO: make some config file for things like this
// can be used to work around temporary problems
func clonePathHack(dirname string, basedir string, gopath string) (string, error) {
	// newdir = helloworld
	// basedir = /home/jcarr/go/src/go.wit.com/apps
	// giturl = https://gitea.wit.com/gui/helloworld
	// func cloneActual(newdir, basedir, giturl string) error {

	switch gopath {
	case "golang.org/x/crypto":
		return cloneActual(dirname, basedir, "https://"+"go.googlesource.com/crypto")
	case "golang.org/x/mod":
		return cloneActual(dirname, basedir, "https://"+"go.googlesource.com/mod")
	case "golang.org/x/net":
		return cloneActual(dirname, basedir, "https://"+"go.googlesource.com/net")
	case "golang.org/x/sys":
		return cloneActual(dirname, basedir, "https://"+"go.googlesource.com/sys")
	case "golang.org/x/sync":
		return cloneActual(dirname, basedir, "https://"+"go.googlesource.com/sync")
	case "golang.org/x/term":
		return cloneActual(dirname, basedir, "https://"+"go.googlesource.com/term")
	case "golang.org/x/text":
		return cloneActual(dirname, basedir, "https://"+"go.googlesource.com/text")
	case "golang.org/x/tools":
		return cloneActual(dirname, basedir, "https://"+"go.googlesource.com/tools")
	case "golang.org/x/xerrors":
		return cloneActual(dirname, basedir, "https://"+"go.googlesource.com/xerrors")
	case "google.golang.org/protobuf":
		return cloneActual(dirname, basedir, "https://"+"go.googlesource.com/protobuf")
	case "google.golang.org/genproto":
		return cloneActual(dirname, basedir, "https://"+"go.googlesource.com/genproto")
	case "google.golang.org/api":
		return cloneActual(dirname, basedir, "https://"+"go.googlesource.com/api")
	case "google.golang.org/grpc":
		return cloneActual(dirname, basedir, "https://"+"go.googlesource.com/grpc")
	case "google.golang.org/appengine":
		return cloneActual(dirname, basedir, "https://"+"go.googlesource.com/appengine")
	}
	if strings.HasPrefix(gopath, "github.com/go-gl/glfw") {
		return cloneActual(dirname, basedir, "https://github.com/go-gl/glfw")
	}

	return "", errors.New("no gopath override here")
}

// attempt to git clone if the go path doesn't exist
// does a git clone, if it works, returns true
// workdir = /home/jcarr/go/src/
// gopath  = go.wit.com/apps/helloworld
func (f *Forge) Clone(gopath string) (*gitpb.Repo, error) {
	var err error
	pb, err := f.Repos.NewGoPath(f.goSrc, gopath, "")
	if err == nil {
		return pb, err
	}
	workdir := f.goSrc
	fullpath := filepath.Join(workdir, gopath)
	dirname := filepath.Base(fullpath)

	basedir := strings.TrimSuffix(fullpath, dirname)

	url := "https://" + gopath
	log.Info("trying git clone")
	log.Info("gopath =", gopath)

	// try a direct git clone against the gopath
	// cloneActual("helloworld", "/home/jcarr/go/src/go.wit.com/apps", "https://go.wit.com/apps/helloworld")
	if finalurl, err := cloneActual(dirname, basedir, url); err == nil {
		f.Repos.DeleteByGoPath(gopath)
		// git clone worked!
		return f.Repos.NewGoPath(f.goSrc, gopath, finalurl)
	}
	log.Info("direct attempt at git clone failed", url)

	// if direct git clone doesn't work, look for a redirect
	// go directly to the URL as that is autoritive. If that failes
	// try the go package system as maybe the git site no longer exists
	if url, err = findGoImport(url); err != nil {
		log.Info("findGoImport() DID NOT WORK", url)
		log.Info("findGoImport() DID NOT WORK", err)
	} else {
		if finalurl, err := cloneActual(dirname, basedir, url); err == nil {
			f.Repos.DeleteByGoPath(gopath)
			// git clone worked!
			return f.Repos.NewGoPath(f.goSrc, gopath, finalurl)
		}
	}
	log.Info("git clone from 'go-import' info failed", url)

	// query the golang package system for the last known location
	// NOTE: take time to thank the go developers and google for designing this wonderful system
	if url, err = runGoList(gopath); err != nil {
		log.Info("go list failed", err)
	} else {
		if finalurl, err := cloneActual(dirname, basedir, url); err == nil {
			f.Repos.DeleteByGoPath(gopath)
			// git clone worked!
			return f.Repos.NewGoPath(f.goSrc, gopath, finalurl)
		}
	}
	log.Info("git clone from 'git list' info failed", url)

	// try to parse a redirect

	if finalurl, err := clonePathHack(dirname, basedir, gopath); err == nil {
		f.Repos.DeleteByGoPath(gopath)
		// WTF didn't go-import or go list work?
		return f.Repos.NewGoPath(f.goSrc, gopath, finalurl)
	}

	return nil, errors.New("can not find git sources for gopath " + gopath)
}

// newdir = helloworld
// basedir = /home/jcarr/go/src/go.wit.com/apps
// giturl = https://gitea.wit.com/gui/helloworld
func cloneActual(newdir, basedir, giturl string) (string, error) {
	log.Info("cloneActual() newdir  =", newdir)
	log.Info("cloneActual() basedir =", basedir)
	log.Info("cloneActual() giturl  =", giturl)
	if !IsDirectory(basedir) {
		os.MkdirAll(basedir, 0750)
	}
	err := os.Chdir(basedir)
	if err != nil {
		log.Warn("chdir failed", basedir, err)
		return giturl, err
	}

	cmd := []string{"git", "clone", "--verbose", "--progress", giturl, newdir}
	log.Info("Running:", basedir, cmd)
	r := shell.PathRunRealtime(basedir, cmd)
	if r.Error != nil {
		log.Warn("git clone error", r.Error)
		return giturl, r.Error
	}

	fullpath := filepath.Join(basedir, newdir)
	if !IsDirectory(fullpath) {
		log.Info("git clone failed", giturl)
		return giturl, errors.New("git clone failed " + giturl)
	}
	gitdir := filepath.Join(fullpath, ".git")
	if IsDirectory(gitdir) {
		log.Info("git cloned worked to", fullpath)
		// also clone notes -- this can store the go.mod and go.sum files
		cmd := []string{"git", "fetch", "origin", "refs/notes/*:refs/notes/*"}
		shell.PathRunRealtime(fullpath, cmd)
		return giturl, nil
	}
	// git clone didn't really work but did make a directory
	log.Info("fullpath is probably empty", fullpath)
	return giturl, errors.New("crapnuts. rmdir fullpath here? " + fullpath)
}

// check the server for the current go path to git url mapping
// for example:
// This will check go.wit.com for "go.wit.com/apps/go-clone"
// and return where the URL to do git clone should be
func findGoImport(url string) (string, error) {
	resp, err := http.Get(url)
	if err != nil {
		return "", err
	}
	defer resp.Body.Close()

	bodyBytes, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return "", err
	}

	tmp := string(bodyBytes)
	parts := strings.Split(tmp, "go-import")
	if len(parts) < 2 {
		return "", errors.New("missing go-import")
	}
	// this is terrible, it doesn't even look for 'content='
	// but again, this is just a hack for my own code to be
	// usuable after the removal in go v1.22 of the go get clone behavior that was in v1.21
	parts = strings.Split(parts[1], "\"")
	var newurl string
	for {
		if len(parts) == 0 {
			break
		}
		tmp := strings.TrimSpace(parts[0])
		fields := strings.Split(tmp, " ")
		// log.Info("FIELDS:", fields)
		if len(fields) == 3 {
			newurl = fields[2]
			break
		}
		parts = parts[1:]
	}
	if newurl == "" {
		return "", errors.New("missing git content string")
	}

	return newurl, nil
}

func IsDirectory(path string) bool {
	info, err := os.Stat(path)
	if err != nil {
		return false
	}
	return info.IsDir()
}