package generator

import (
	"fmt"
	"net/url"
	"strconv"
	"strings"
)

// GroupDefinition captures parsed custom proxy group metadata.
type GroupDefinition struct {
	Name         string
	Type         string
	Proxies      []string
	UseProviders []string
	URL          string
	Interval     *int
	Timeout      *int
	Tolerance    *int
	Extras       map[string]string
}

// ParseGroupDefinition converts a custom group definition string into a GroupDefinition.
func ParseGroupDefinition(definition string) (*GroupDefinition, error) {
	values, err := url.ParseQuery(definition)
	if err != nil {
		return nil, fmt.Errorf("invalid group definition: %v", err)
	}

	name := strings.TrimSpace(values.Get("name"))
	if name == "" {
		return nil, fmt.Errorf("custom group missing name")
	}

	typeVal := strings.TrimSpace(values.Get("type"))
	if typeVal == "" {
		typeVal = "select"
	}

	group := &GroupDefinition{
		Name:   name,
		Type:   typeVal,
		Extras: make(map[string]string),
	}

	if proxyStr := strings.TrimSpace(values.Get("proxies")); proxyStr != "" {
		parts := strings.Split(proxyStr, ",")
		for _, entry := range parts {
			entry = strings.TrimSpace(entry)
			if entry != "" {
				group.Proxies = append(group.Proxies, entry)
			}
		}
	}

	if useStr := strings.TrimSpace(values.Get("use")); useStr != "" {
		parts := strings.Split(useStr, ",")
		for _, entry := range parts {
			entry = strings.TrimSpace(entry)
			if entry != "" {
				group.UseProviders = append(group.UseProviders, entry)
			}
		}
	}

	if raw := strings.TrimSpace(values.Get("url")); raw != "" {
		group.URL = raw
	}
	if raw := strings.TrimSpace(values.Get("interval")); raw != "" {
		if n, err := strconv.Atoi(raw); err == nil && n >= 0 {
			group.Interval = &n
		} else {
			return nil, fmt.Errorf("invalid interval for group %s: %v", name, err)
		}
	}
	if raw := strings.TrimSpace(values.Get("timeout")); raw != "" {
		if n, err := strconv.Atoi(raw); err == nil && n >= 0 {
			group.Timeout = &n
		} else {
			return nil, fmt.Errorf("invalid timeout for group %s: %v", name, err)
		}
	}
	if raw := strings.TrimSpace(values.Get("tolerance")); raw != "" {
		if n, err := strconv.Atoi(raw); err == nil && n >= 0 {
			group.Tolerance = &n
		} else {
			return nil, fmt.Errorf("invalid tolerance for group %s: %v", name, err)
		}
	}

	for key, vals := range values {
		if key == "name" || key == "type" || key == "proxies" || key == "use" || key == "url" || key == "interval" || key == "timeout" || key == "tolerance" {
			continue
		}
		if len(vals) == 0 {
			continue
		}
		value := strings.TrimSpace(vals[len(vals)-1])
		if value == "" {
			continue
		}
		group.Extras[strings.ReplaceAll(key, "_", "-")] = value
	}

	return group, nil
}