package web

import (
	"net/http"
	"path/filepath"
	"runtime"
	"strings"
)

const (
	resourceInstallerMutation = "installer:mutation"
	resourceManagerConfig     = "config:manager"
	resourceMPVConfig         = "config:mpv"
	resourceManagerBinary     = "install:manager-binary"
	resourceKeyring           = "keyring:sudo-password"
)

// installerOperationResources deliberately includes conservative shared
// resources as well as exact identities. This prevents unlike method IDs from
// overlapping on manager state, an MPV config/UI tree, an install target, or a
// package-manager database while retaining a path toward finer concurrency.
func installerOperationResources(methodID, appID, installPath, configDir string) []string {
	resources := []string{
		resourceInstallerMutation,
		resourceManagerConfig,
		resourceMPVConfig,
		resourceKeyring,
		"method:" + methodID,
	}
	if appID != "" {
		resources = append(resources, "app:"+appID)
	}
	if installPath != "" {
		resources = append(resources, "install-path:"+normalizedLeasePath(installPath))
	}
	if configDir != "" {
		resources = append(resources, "config-tree:"+normalizedLeasePath(configDir))
	}
	if packageResource := packageManagerResource(methodID); packageResource != "" {
		resources = append(resources, packageResource)
	}
	return resources
}

func packageManagerResource(methodID string) string {
	lower := strings.ToLower(methodID)
	switch {
	case strings.Contains(lower, "flatpak"):
		return "package-manager:flatpak"
	case strings.Contains(lower, "snap"):
		return "package-manager:snap"
	case strings.Contains(lower, "brew"):
		return "package-manager:brew"
	case strings.Contains(lower, "package"):
		return "package-manager:system"
	default:
		return ""
	}
}

func normalizedLeasePath(path string) string {
	if absolute, err := filepath.Abs(path); err == nil {
		path = absolute
	}
	path = filepath.Clean(path)
	if runtime.GOOS == "windows" {
		path = strings.ToLower(path)
	}
	return path
}

// withOperationLease includes synchronous config/UI mutations in the same
// coordinator as background jobs. Read-only methods do not acquire leases.
func (s *Server) withOperationLease(handler http.HandlerFunc, resources ...string) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		if r.Method == http.MethodGet || r.Method == http.MethodHead || r.Method == http.MethodOptions {
			handler(w, r)
			return
		}
		owner := "request:" + newJobID()
		release, ok := s.jobManager.TryAcquireResources(owner, resources...)
		if !ok {
			sendJSONError(w, http.StatusConflict, "A conflicting install or configuration operation is already in progress")
			return
		}
		defer release()
		handler(w, r)
	}
}