// Copyright 2025 Versity Software
// This file is licensed under the Apache License, Version 2.0
// (the "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

package gwcli

import (
	"errors"
	"fmt"
	"plugin"

	"github.com/urfave/cli/v2"
	"github.com/versity/versitygw/plugins"
)

// PluginCommand returns the "plugin" subcommand, common to all versitygw
// binaries.
func PluginCommand() *cli.Command {
	return &cli.Command{
		Name:        "plugin",
		Usage:       "load a backend from a plugin",
		Description: "Runs a s3 gateway and redirects the requests to the backend defined in the plugin",
		Action:      runPluginBackend,
		Flags: []cli.Flag{
			&cli.StringFlag{
				Name:    "config",
				Usage:   "location of the plugin config file",
				Aliases: []string{"c"},
				EnvVars: []string{"VGW_PLUGIN_CONFIG"},
			},
		},
	}
}

func runPluginBackend(ctx *cli.Context) error {
	if ctx.NArg() == 0 {
		return fmt.Errorf("no plugin file provided to be loaded")
	}

	pluginPath := ctx.Args().Get(0)
	config := ctx.String("config")

	p, err := plugin.Open(pluginPath)
	if err != nil {
		return err
	}

	backendSymbol, err := p.Lookup("Backend")
	if err != nil {
		return err
	}
	backendPluginPtr, ok := backendSymbol.(*plugins.BackendPlugin)
	if !ok {
		return errors.New("plugin is not of type *plugins.BackendPlugin")
	}

	if backendPluginPtr == nil {
		return errors.New("variable Backend is nil")
	}

	be, err := (*backendPluginPtr).New(config)
	if err != nil {
		return err
	}

	return RunGateway(ctx.Context, be)
}