package main

import (
	"encoding/json"
	"os"
	"strings"
	"testing"
)

// The manifest and this code say one thing: the paths the guard keeps are the files the mesh renders, the
// process runs this binary as the guard, and the resolver file and its kept copy are one template.

type manifest struct {
	Claims []struct {
		Name   string   `json:"name"`
		Serves []string `json:"serves"`
	} `json:"claims"`
	Provides []struct {
		Name  string `json:"name"`
		Reach string `json:"reach"`
	} `json:"provides"`
	Upgrade struct {
		Policy string `json:"policy"`
		Why    string `json:"why"`
	} `json:"upgrade"`
	Facts map[string]struct {
		Path     string `json:"path"`
		Template string `json:"template"`
	} `json:"facts"`
	Resources []map[string]any `json:"resources"`
	Build     struct {
		Artifacts []struct {
			Binary string `json:"binary"`
		} `json:"artifacts"`
	} `json:"build"`
}

func theManifest(t *testing.T) manifest {
	t.Helper()
	raw, err := os.ReadFile("../../module.json")
	if err != nil {
		t.Fatal(err)
	}
	var m manifest
	if err := json.Unmarshal(raw, &m); err != nil {
		t.Fatal(err)
	}
	return m
}

func TestTheManifestSaysWhatTheGuardKeeps(t *testing.T) {
	m := theManifest(t)
	if m.Facts["resolvers"].Path != ResolvConf || m.Facts["kept"].Path != KeptPath || m.Facts["suffix"].Path != SuffixPath {
		t.Errorf("the rendered paths are not the ones the guard reads: %+v", m.Facts)
	}
	if m.Facts["resolvers"].Template != m.Facts["kept"].Template {
		t.Error("the resolver file and the copy the guard puts back are not one template")
	}
	// Sorted before the live file, so the mesh writes the copy first and the guard never puts back the
	// file it is about to be given.
	if !("kept" < "resolvers") {
		t.Error("the kept copy is not rendered before the file")
	}
	if !strings.HasPrefix(m.Facts["resolvers"].Template, "# Managed by the mesh") {
		t.Error("the resolver file does not begin as the mesh's own does, which is how the uplink's verb reads it")
	}
	var lines []string
	for _, l := range strings.Split(m.Facts["resolvers"].Template, "\n") {
		if strings.Contains(l, "nameserver") && !strings.HasPrefix(l, "#") {
			lines = append(lines, l)
		}
	}
	if len(lines) != 1 || strings.Contains(m.Facts["resolvers"].Template, "search ") {
		t.Errorf("the resolver file lists more than this machine's own resolver: %v", lines)
	}
	conf := m.Facts["resolved"].Template
	for _, want := range []string{`DNS={{range index .Holders "mesh-dns-resolver"}}`, "\nDomains=~.\n", "\nFallbackDNS=\n",
		"DNSStubListenerExtra={{$own}}\n", "\nCache=no\n", "\nLLMNR=no\n", "\nMulticastDNS=no\n"} {
		if !strings.Contains(conf, want) {
			t.Errorf("resolved's drop-in lacks %q", want)
		}
	}
	guard, service := false, false
	for _, r := range m.Resources {
		run, _ := r["run"].([]any)
		if r["type"] == "process" && len(run) == 2 && run[0] == "./"+m.Build.Artifacts[0].Binary && run[1] == "guard" {
			guard = r["user"] == nil && r["run-once"] == nil && r["health"] != nil
		}
		if r["type"] == "service" && r["unit"] == "systemd-resolved.service" {
			on, _ := r["restart-on"].([]any)
			service = r["state"] == "running" && len(on) == 1 && on[0] == "systemd-resolved.fact-resolved" && r["health"] != nil
		}
	}
	if !guard || !service {
		t.Errorf("the guard (root, long-running, its health said) %v; resolved (running, restarted on its drop-in) %v", guard, service)
	}
	if len(m.Claims) != 1 || m.Claims[0].Name != Seat || strings.Join(m.Claims[0].Serves, " ") != "routes route unroute" {
		t.Errorf("the claim is %+v", m.Claims)
	}
	if len(m.Provides) != 1 || m.Provides[0].Name != "split-dns" || m.Provides[0].Reach != "machine" {
		t.Errorf("split-dns is not provided at the machine's reach: %+v", m.Provides)
	}
	if m.Upgrade.Policy != "record" || m.Upgrade.Why == "" {
		t.Error("a build of the machine's names rolls out on its own")
	}
}

// Every verb the claim serves is a tool of the bundle, by the seat's name.
func TestTheBundleServesTheClaimedVerbs(t *testing.T) {
	have := map[string]bool{}
	for _, tool := range tools(&Resolver{}, "") {
		have[tool.Name] = true
	}
	for _, v := range theManifest(t).Claims[0].Serves {
		if !have[Seat+"."+v] {
			t.Errorf("%s.%s is claimed and not served", Seat, v)
		}
	}
}