package config

import (
	"crypto/sha256"
	"fmt"
	"net/url"
	"path/filepath"
	"regexp"
	"sort"
	"strings"
)

var instanceName = regexp.MustCompile(`^[a-zA-Z0-9][a-zA-Z0-9_-]*$`)

// ValidateNetBoxes keeps source names usable as instance/hostname selectors.
func (c *Config) ValidateNetBoxes() error {
	if len(c.NetBoxes) > 0 && c.NetBox.URL != "" {
		return fmt.Errorf("configure either netbox or netboxes, not both")
	}
	seen := make(map[string]bool)
	for _, source := range c.NetBoxes {
		if !instanceName.MatchString(source.Name) {
			return fmt.Errorf("netboxes.name %q must contain only letters, digits, underscores, or hyphens", source.Name)
		}
		name := strings.ToLower(source.Name)
		if seen[name] {
			return fmt.Errorf("duplicate NetBox instance name %q", source.Name)
		}
		seen[name] = true
		u, err := url.Parse(source.URL)
		if err != nil || (u.Scheme != "http" && u.Scheme != "https") || u.Host == "" || u.RawQuery != "" || u.Fragment != "" {
			return fmt.Errorf("NetBox %q requires an HTTP(S) URL without query or fragment", source.Name)
		}
		if source.TokenVersion < 0 || source.TokenVersion > 2 {
			return fmt.Errorf("NetBox %q: token_version must be 0, 1, or 2", source.Name)
		}
	}
	return nil
}

func (c *Config) HasNetBox() bool { return c.NetBox.URL != "" || len(c.NetBoxes) > 0 }

// CachePath isolates named sources from legacy caches and from changed endpoints.
// Rotating a token or reordering the sources does not discard usage history.
func (c *Config) CachePath() string {
	if len(c.NetBoxes) == 0 {
		return c.Cache.Path
	}
	var identities []string
	for _, source := range c.NetBoxes {
		identities = append(identities, strings.ToLower(source.Name)+"\x00"+strings.TrimRight(source.URL, "/"))
	}
	sort.Strings(identities)
	sum := sha256.Sum256([]byte(strings.Join(identities, "\x00")))
	return filepath.Join(filepath.Dir(c.Cache.Path), fmt.Sprintf("instances-%x", sum[:8]), filepath.Base(c.Cache.Path))
}