option.go

// Copyright 2025 Blink Labs Software
//
// 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 plugin

import (
	"fmt"
	"os"
	"strconv"
	"strings"

	"github.com/spf13/pflag"
)

type PluginOptionType int

const (
	PluginOptionTypeString PluginOptionType = 1
	PluginOptionTypeBool   PluginOptionType = 2
	PluginOptionTypeInt    PluginOptionType = 3
	PluginOptionTypeUint   PluginOptionType = 4
)

type PluginOption struct {
	DefaultValue any
	Dest         any
	Name         string
	CustomEnvVar string
	CustomFlag   string
	Description  string
	Type         PluginOptionType
}

func (p *PluginOption) AddToFlagSet(
	fs *pflag.FlagSet,
	pluginType string,
	pluginName string,
) error {
	var flagName string
	if p.CustomFlag != "" {
		flagName = fmt.Sprintf("%s-%s", pluginType, p.CustomFlag)
	} else {
		flagName = fmt.Sprintf("%s-%s-%s", pluginType, pluginName, p.Name)
	}
	switch p.Type {
	case PluginOptionTypeString:
		fs.StringVar(
			p.Dest.(*string),
			flagName,
			p.DefaultValue.(string),
			p.Description,
		)
	case PluginOptionTypeBool:
		fs.BoolVar(
			p.Dest.(*bool),
			flagName,
			p.DefaultValue.(bool),
			p.Description,
		)
	case PluginOptionTypeInt:
		fs.IntVar(p.Dest.(*int), flagName, p.DefaultValue.(int), p.Description)
	case PluginOptionTypeUint:
		fs.UintVar(
			p.Dest.(*uint),
			flagName,
			p.DefaultValue.(uint),
			p.Description,
		)
	default:
		return fmt.Errorf(
			"unknown plugin option type %d for option %s",
			p.Type,
			p.Name,
		)
	}
	return nil
}

func (p *PluginOption) ProcessEnvVars(envPrefix string) error {
	envVars := []string{
		// Automatically generate env var from specified prefix and option name
		strings.ToUpper(
			strings.ReplaceAll(
				fmt.Sprintf(
					"%s%s",
					envPrefix,
					p.Name,
				),
				"-",
				"_",
			),
		),
	}
	// Also check any custom env var specified
	if p.CustomEnvVar != "" {
		envVars = append(envVars, p.CustomEnvVar)
	}
	for _, envVar := range envVars {
		if value, ok := os.LookupEnv(envVar); ok {
			switch p.Type {
			case PluginOptionTypeString:
				*(p.Dest.(*string)) = value
			case PluginOptionTypeBool:
				value, err := strconv.ParseBool(value)
				if err != nil {
					return fmt.Errorf("error processing env vars: %w", err)
				}
				*(p.Dest.(*bool)) = value
			case PluginOptionTypeInt:
				// We limit to 32-bit to not get inconsistent behavior on 32-bit platforms
				value, err := strconv.ParseInt(value, 10, 32)
				if err != nil {
					return fmt.Errorf("error processing env vars: %w", err)
				}
				*(p.Dest.(*int)) = int(value)
			case PluginOptionTypeUint:
				// We limit to 32-bit to not get inconsistent behavior on 32-bit platforms
				value, err := strconv.ParseUint(value, 10, 32)
				if err != nil {
					return fmt.Errorf("error processing env vars: %w", err)
				}
				*(p.Dest.(*uint)) = uint(value)
			default:
				return fmt.Errorf(
					"unknown plugin option type %d for option %s",
					p.Type,
					p.Name,
				)
			}
		}
	}
	return nil
}

func (p *PluginOption) ProcessConfig(
	pluginData map[any]any,
) error {
	if optionData, ok := pluginData[p.Name]; ok {
		switch p.Type {
		case PluginOptionTypeString:
			switch value := optionData.(type) {
			case string:
				*(p.Dest.(*string)) = value
			default:
				return fmt.Errorf("invalid value for option '%s': expected string and got %T", p.Name, optionData)
			}
		case PluginOptionTypeBool:
			switch value := optionData.(type) {
			case bool:
				*(p.Dest.(*bool)) = value
			default:
				return fmt.Errorf("invalid value for option '%s': expected bool and got %T", p.Name, optionData)
			}
		case PluginOptionTypeInt:
			switch value := optionData.(type) {
			case int:
				*(p.Dest.(*int)) = value
			default:
				return fmt.Errorf("invalid value for option '%s': expected int and got %T", p.Name, optionData)
			}
		case PluginOptionTypeUint:
			switch value := optionData.(type) {
			case int:
				if value < 0 {
					return fmt.Errorf("invalid value for option '%s': negative value: %T", p.Name, optionData)
				}
				*(p.Dest.(*uint)) = uint(value)
			default:
				return fmt.Errorf("invalid value for option '%s': expected uint and got %T", p.Name, optionData)
			}
		default:
			return fmt.Errorf(
				"unknown plugin option type %d for option %s",
				p.Type,
				p.Name,
			)
		}
	}
	return nil
}