package service

import (
	"encoding/json"
	"fmt"
	"io/fs"
	"net/http"
	"os"
	"path/filepath"
	"plugin"
	"slices"
	"time"

	configurator "git.towk2.me/towk/configurator/pkg"
	"git.towk2.me/towk/configurator/pkg/util"
	"github.com/go-chi/chi/middleware"
	"github.com/go-chi/chi/v5"
)

const (
	PLUGINS_RELPATH   = "/plugins"
	TEMPLATES_RELPATH = "/templates"
	PROFILES_RELPATH  = "/profiles"
)

type Service struct {
	RootPath    string `yaml:"root,omitempty"`
	Environment map[string]string

	// max counts
	PluginsMaxCount  int
	ProfilesMaxCount int
}

// New creates the directories at specified path
func New() *Service {
	return &Service{
		RootPath: ".",
		Environment: map[string]string{
			"CONFIGURATOR_HOST_URI": "",
			"ACCESS_TOKEN":          "",
		},
		PluginsMaxCount:  64,
		ProfilesMaxCount: 256,
	}
}

// Serve() starts the configurator service and waits for requests.
func (s *Service) Serve() error {
	router := chi.NewRouter()
	router.Use(middleware.RequestID)
	router.Use(middleware.RealIP)
	router.Use(middleware.Logger)
	router.Use(middleware.Recoverer)
	router.Use(middleware.StripSlashes)
	router.Use(middleware.Timeout(60 * time.Second))

	if s.requireAuth() {

	} else {
		// general
		router.Get("/download/*", s.Download())
		router.Post("/upload", s.Upload())
		router.Get("/list", s.List())

		// profiles
		router.Get("/profiles", s.GetProfiles())
		// router.Post("/profiles", s.CreateProfiles())
		router.Get("/profile/{id}", s.GetProfile())
		router.Post("/profile/{id}", s.CreateProfile())
		router.Get("/profile/{id}/data", s.GetProfileData())
		router.Post("/profile/{id}/data", s.SetProfileData())
		router.Delete("/profile/{id}/data", s.DeleteProfileData())
		// router.Post("/profile/{id}/paths/{path}", s.CreateProfilePath())
		// router.Delete("/profile/{id}/paths/{path}", s.DeleteProfilePath())
		// router.Get("/profile/{id}/paths/{path}", s.GetProfilePath())

		// plugins
		router.Get("/plugins", s.GetPlugins())
		router.Post("/plugins", s.CreatePlugins())
		router.Delete("/plugins/{id}", s.DeletePlugins())
	}

	// always available public routes go here
	router.HandleFunc("/status", s.GetStatus)
	return http.ListenAndServe(":8080", router)
}

func (s *Service) requireAuth() bool {
	return false
}

func (s *Service) FetchJwks(uri string) {

}

func LoadProfileFromFile(path string) (*Profile, error) {
	return loadFromJSONFile[Profile](path)
}

// LoadPluginFromFile loads a single plugin given a single file path
func LoadPluginFromFile(path string) (configurator.Plugin, error) {
	var (
		isDir        bool
		err          error
		loadedPlugin *plugin.Plugin
	)
	// skip loading plugin if path is a directory with no error
	if isDir, err = util.IsDirectory(path); err == nil && isDir {
		return nil, nil
	} else if err != nil {
		return nil, fmt.Errorf("failed to test if plugin path is directory: %v", err)
	}

	// try and open the plugin
	loadedPlugin, err = plugin.Open(path)
	if err != nil {
		return nil, fmt.Errorf("failed to open plugin at path '%s': %v", path, err)
	}

	// load the "Target" symbol from plugin
	symbol, err := loadedPlugin.Lookup("Target")
	if err != nil {
		return nil, fmt.Errorf("failed to look up symbol at path '%s': %v", path, err)
	}

	// assert that the plugin is a valid configurator.Plugin
	target, ok := symbol.(configurator.Plugin)
	if !ok {
		return nil, fmt.Errorf("failed to load the correct symbol type at path '%s'", path)
	}
	return target, nil
}

// LoadPluginsFromDir loads all plugins in a given directory.
//
// Returns a map of plugins. Each plugin can be accessed by the name
// returned by the plugin.GetName() implemented.
func LoadPluginsFromDir(dirpath string) (map[string]configurator.Plugin, error) {
	// check if verbose option is supplied
	var (
		cps = make(map[string]configurator.Plugin)
		err error
	)

	// helper to check for valid extensions
	var hasValidExt = func(path string) bool {
		var validExts = []string{".so", ".dylib", ".dll"}
		return slices.Contains(validExts, filepath.Ext(path))
	}

	// walk all files in directory only loading *valid* plugins
	err = filepath.Walk(dirpath, func(path string, info fs.FileInfo, err error) error {
		// skip trying to load generator plugin if directory or error
		if info.IsDir() || err != nil {
			return nil
		}

		// only try loading if file has .so extension
		if hasValidExt(path) {
			return nil
		}

		// load the plugin from current path
		p, err := LoadPluginFromFile(path)
		if err != nil {
			return fmt.Errorf("failed to load plugin in directory '%s': %v", path, err)
		}

		// map each plugin by name for lookup
		cps[p.Name()] = p
		return nil
	})

	if err != nil {
		return nil, fmt.Errorf("failed to walk directory '%s': %v", dirpath, err)
	}

	return cps, nil
}

func SaveProfileToFile(path string, profile *Profile) error {
	return saveToJSONFile(path, profile)
}

func SavePluginToFile(path string, plugin *configurator.Plugin) error {
	return saveToJSONFile(path, plugin)
}

func loadFromJSONFile[T any](path string) (*T, error) {
	var (
		res      *T
		contents []byte
		err      error
	)

	contents, err = os.ReadFile(path)
	if err != nil {
		return nil, fmt.Errorf("failed to read plugin file: %v", err)
	}

	err = json.Unmarshal(contents, &res)
	if err != nil {
		return nil, fmt.Errorf("failed to unmarshal plugin: %v", err)
	}

	return res, err
}

func saveToJSONFile[T any](path string, data T) error {
	var (
		contents []byte
		err      error
	)
	contents, err = json.Marshal(data)
	if err != nil {
		return fmt.Errorf("failed to marshal data to JSON: %v", err)
	}
	err = os.WriteFile(path, contents, os.ModePerm)
	if err != nil {
		return fmt.Errorf("failed to write JSON to file: %v", err)
	}

	return nil
}

func (s *Service) PathForProfileWithID(id string) string {
	return s.RootPath + PROFILES_RELPATH + "/" + id
}

func (s *Service) PathForPlugins() string {
	return s.RootPath + PLUGINS_RELPATH
}