package filesafety

import (
	"errors"
	"strconv"
	"strings"

	"github.com/tinode/chat/server/filesafety/aliyun"
	"github.com/tinode/chat/server/store"
	"github.com/tinode/chat/server/store/types"
)

const thirdPartyConfigGroup = "im_third_party"

type ContentReviewConfig struct {
	Enabled  bool
	Provider string
	Green    aliyun.GreenConfig
}

type MalwareReviewConfig struct {
	Enabled  bool
	Provider string
	RegionID string
}

type Config struct {
	Content ContentReviewConfig
	Malware MalwareReviewConfig
}

func LoadConfig() (*Config, error) {
	values, err := store.ThirdPartyConfig.Get(thirdPartyConfigGroup,
		"file_review_content_enabled",
		"file_review_content_provider",
		"aliyun_green_region_id",
		"aliyun_green_endpoint",
		"aliyun_green_document_service",
		"file_review_malware_enabled",
		"file_review_malware_provider",
		"aliyun_sas_region_id",
		"aliyun_access_key_id",
		"aliyun_access_key_secret",
	)
	if err != nil {
		return nil, err
	}

	config := &Config{
		Content: ContentReviewConfig{
			Enabled:  boolValue(values["file_review_content_enabled"]),
			Provider: stringDefault(values["file_review_content_provider"], types.FileReviewProviderAliyunGreen),
			Green: aliyun.GreenConfig{
				AccessKeyID:     strings.TrimSpace(values["aliyun_access_key_id"]),
				AccessKeySecret: strings.TrimSpace(values["aliyun_access_key_secret"]),
				RegionID:        strings.TrimSpace(values["aliyun_green_region_id"]),
				Endpoint:        strings.TrimSpace(values["aliyun_green_endpoint"]),
				DocumentService: strings.TrimSpace(values["aliyun_green_document_service"]),
			},
		},
		Malware: MalwareReviewConfig{
			Enabled:  boolValue(values["file_review_malware_enabled"]),
			Provider: stringDefault(values["file_review_malware_provider"], types.FileReviewProviderAliyunSAS),
			RegionID: strings.TrimSpace(values["aliyun_sas_region_id"]),
		},
	}
	if config.Content.Enabled && config.Content.Provider != types.FileReviewProviderAliyunGreen {
		return nil, errors.New("unsupported file content review provider: " + config.Content.Provider)
	}
	if config.Malware.Enabled && config.Malware.Provider != types.FileReviewProviderAliyunSAS {
		return nil, errors.New("unsupported malware review provider: " + config.Malware.Provider)
	}
	return config, nil
}

func NewGreenClientFromConfig() (*aliyun.GreenClient, error) {
	config, err := LoadConfig()
	if err != nil {
		return nil, err
	}
	if !config.Content.Enabled {
		return nil, types.ErrUnsupported
	}
	return aliyun.NewGreenClient(config.Content.Green)
}

func boolValue(value string) bool {
	if parsed, err := strconv.ParseBool(strings.TrimSpace(value)); err == nil {
		return parsed
	}
	switch strings.ToLower(strings.TrimSpace(value)) {
	case "1", "yes", "on":
		return true
	default:
		return false
	}
}

func stringDefault(value, fallback string) string {
	if value = strings.TrimSpace(value); value != "" {
		return value
	}
	return fallback
}