package namer

import (
	"sort"

	"go-common/app/tool/gengo/types"
)

// DefaultImportTracker is
// ImportTracker may be passed to a namer.RawNamer, to track the imports needed
// for the types it names.
//
// TODO: pay attention to the package name (instead of renaming every package).
type DefaultImportTracker struct {
	pathToName map[string]string
	// forbidden names are in here. (e.g. "go" is a directory in which
	// there is code, but "go" is not a legal name for a package, so we put
	// it here to prevent us from naming any package "go")
	nameToPath map[string]string
	local      types.Name

	// Returns true if a given types is an invalid type and should be ignored.
	IsInvalidType func(*types.Type) bool
	// Returns the final local name for the given name
	LocalName func(types.Name) string
	// Returns the "import" line for a given (path, name).
	PrintImport func(string, string) string
}

// NewDefaultImportTracker is
func NewDefaultImportTracker(local types.Name) DefaultImportTracker {
	return DefaultImportTracker{
		pathToName: map[string]string{},
		nameToPath: map[string]string{},
		local:      local,
	}
}

// AddTypes is
func (tracker *DefaultImportTracker) AddTypes(types ...*types.Type) {
	for _, t := range types {
		tracker.AddType(t)
	}
}

// AddType is
func (tracker *DefaultImportTracker) AddType(t *types.Type) {
	if tracker.local.Package == t.Name.Package {
		return
	}

	if tracker.IsInvalidType(t) {
		if t.Kind == types.Builtin {
			return
		}
		if _, ok := tracker.nameToPath[t.Name.Package]; !ok {
			tracker.nameToPath[t.Name.Package] = ""
		}
		return
	}

	if len(t.Name.Package) == 0 {
		return
	}
	path := t.Name.Path
	if len(path) == 0 {
		path = t.Name.Package
	}
	if _, ok := tracker.pathToName[path]; ok {
		return
	}
	name := tracker.LocalName(t.Name)
	tracker.nameToPath[name] = path
	tracker.pathToName[path] = name
}

// ImportLines is
func (tracker *DefaultImportTracker) ImportLines() []string {
	importPaths := []string{}
	for path := range tracker.pathToName {
		importPaths = append(importPaths, path)
	}
	sort.Sort(sort.StringSlice(importPaths))
	out := []string{}
	for _, path := range importPaths {
		out = append(out, tracker.PrintImport(path, tracker.pathToName[path]))
	}
	return out
}

// LocalNameOf returns the name you would use to refer to the package at the
// specified path within the body of a file.
func (tracker *DefaultImportTracker) LocalNameOf(path string) string {
	return tracker.pathToName[path]
}

// PathOf returns the path that a given localName is referring to within the
// body of a file.
func (tracker *DefaultImportTracker) PathOf(localName string) (string, bool) {
	name, ok := tracker.nameToPath[localName]
	return name, ok
}