package ctx

import (
	"errors"
	"path/filepath"

	"github.com/zeromicro/go-zero/tools/goctl/rpc/execx"
)

var errModuleCheck = errors.New("the work directory must be found in the go mod or the $GOPATH")

// ProjectContext is a structure for the project,
// which contains WorkDir, Name, Path and Dir
type ProjectContext struct {
	WorkDir string
	// Name is the root name of the project
	// eg: go-zero、greet
	Name string
	// Path identifies which module a project belongs to, which is module value if it's a go mod project,
	// or else it is the root name of the project, eg: github.com/zeromicro/go-zero、greet
	Path string
	// Dir is the path of the project, eg: /Users/keson/goland/go/go-zero、/Users/keson/go/src/greet
	Dir string
}

// Prepare checks the project which module belongs to,and returns the path and module.
// workDir parameter is the directory of the source of generating code,
// where can be found the project path and the project module,
func Prepare(workDir string) (*ProjectContext, error) {
	return PrepareWithModule(workDir, "")
}

// PrepareWithModule checks the project which module belongs to,and returns the path and module.
// workDir parameter is the directory of the source of generating code,
// where can be found the project path and the project module,
// moduleName parameter is the custom module name to use if creating a new go.mod
func PrepareWithModule(workDir string, moduleName string) (*ProjectContext, error) {
	ctx, err := background(workDir)
	if err == nil {
		return ctx, nil
	}

	var name string
	if len(moduleName) > 0 {
		name = moduleName
	} else {
		name = filepath.Base(workDir)
	}

	_, err = execx.Run("go mod init "+name, workDir)
	if err != nil {
		return nil, err
	}

	return background(workDir)
}

func background(workDir string) (*ProjectContext, error) {
	isGoMod, err := IsGoMod(workDir)
	if err != nil {
		return nil, err
	}

	if isGoMod {
		return projectFromGoMod(workDir)
	}
	return projectFromGoPath(workDir)
}
