/*
 *   Copyright (C) 2021 Arsen Musayelyan
 *
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

package main

import (
	"fmt"
	"github.com/traefik/yaegi/interp"
	"github.com/traefik/yaegi/stdlib"
	"github.com/traefik/yaegi/stdlib/unrestricted"
	"io/fs"
	"path/filepath"
)

// Create type for plugin functions
type pluginFunc func(string, map[string]interface{})

// Initialize all available plugins
func initPlugins(gopath string) map[string]pluginFunc {
	log.Info().Msg("Initializing plugins")
	out := map[string]pluginFunc{}

	// Create new yaegi Go interpreter with appropriate GOPATH
	i := interp.New(interp.Options{GoPath: gopath})
	// Use standard library symbols
	i.Use(stdlib.Symbols)
	// Use unrestricted symbols (os/exec, syscall, etc.)
	i.Use(unrestricted.Symbols)
	// Use custom package
	i.Use(tridentSymbols)

	// Walk plugin directory
	err := filepath.WalkDir(filepath.Join(execDir, "plugins"), func(path string, d fs.DirEntry, err error) error {
		// If error encountered, return
		if err != nil {
			return err
		}
		// If current path is not a directory or it is the plugin root
		if !d.IsDir() || d.Name() == "plugins" {
			return nil
		}

		// Get name of plugin from directory name
		pluginName := filepath.Base(path)
		// IF plugin already exists, return error
		if _, ok := out[pluginName]; ok {
			return fmt.Errorf("plugin %s has already been initialized", pluginName)
		}
		// If verbose, log which plugin is being initialized
		if *verbose {
			log.Debug().Str("plugin", pluginName).Msg("Initializing plugin")
		}
		// Walk directory of specific plugin
		err = filepath.WalkDir(path, func(path string, d fs.DirEntry, err error) error {
			// If error encountered, return
			if err != nil {
				return err
			}
			// If file is not go source, skip
			if filepath.Ext(path) != ".go" {
				return nil
			}
			// Evaluate go file
			_, err = i.EvalPath(path)
			if err != nil {
				return err
			}
			return nil
		})
		// If error encountered walking plugin, return
		if err != nil {
			return err
		}
		// Get RunPlugin symbol from current plugin
		v, err := i.Eval(fmt.Sprintf("%s.RunPlugin", pluginName))
		if err != nil {
			return err
		}
		// Assert RunPlugin symbol as a plugin function and add it to out map
		out[pluginName] = v.Interface().(func(string, map[string]interface{}))
		return nil
	})
	// If error occurred walking directory, log fatally
	if err != nil {
		log.Fatal().Err(err).Msg("Error initializing plugins")
	}
	return out
}