package main

import (
	"encoding/json"
	"os"
	"path/filepath"
	"regexp"
	"strconv"
	"strings"
	"testing"
)

// The module's directory, where its manifest and its files/ are.
const moduleDir = "../.."

// templateText is the text a file resource places on the machine: its template's, in the module's files/
// (novox/hq ADR 0349 §2). A resource that names no template, or a template that is not there, fails the test.
func templateText(t *testing.T, r map[string]any) string {
	t.Helper()
	name, _ := r["template"].(string)
	if name == "" {
		t.Fatalf("resource %v names no template", r["id"])
	}
	raw, err := os.ReadFile(filepath.Join(moduleDir, filepath.FromSlash(name)))
	if err != nil {
		t.Fatalf("resource %v names %s: %v", r["id"], name, err)
	}
	return string(raw)
}

// No file resource carries its text inline: each names its template in files/, and the build packs files/
// into the one archive the controller reads the templates back from (novox/hq ADR 0349 §2).
func TestEveryFileTakesItsTextFromATemplate(t *testing.T) {
	raw, err := os.ReadFile(filepath.Join(moduleDir, "module.json"))
	if err != nil {
		t.Fatal(err)
	}
	var m struct {
		Resources []map[string]any `json:"resources"`
		Build     struct {
			Artifacts []map[string]any `json:"artifacts"`
		} `json:"build"`
	}
	if err := json.Unmarshal(raw, &m); err != nil {
		t.Fatal(err)
	}
	for _, r := range m.Resources {
		if _, inline := r["content"]; inline {
			t.Errorf("resource %v keeps its text inline: keep it in files/ and name it as the template", r["id"])
		}
		if r["type"] == "file" {
			templateText(t, r)
		}
	}
	packs := 0
	for _, a := range m.Build.Artifacts {
		if a["kind"] == "archive" && a["from"] == "files" {
			packs++
			if a["name"] != "files" {
				t.Errorf("the templates archive is named %v, not files", a["name"])
			}
		}
	}
	if packs != 1 {
		t.Errorf("the build packs files/ into %d archives, not one", packs)
	}
}

// The packaged dnsmasq.service orders itself Before= network-online.target and nss-lookup.target. A drop-in
// that orders it After= either of them makes an ordering cycle, and systemd drops the start job: the mesh
// resolver stayed down for 90 minutes at a boot (novox/hq issue 1126). Wants=, Requires= and BindsTo= are
// refused too: they pull the target in, and with the packaged ordering they are the same mistake. Because the
// tunnel is ordered after those targets, the drop-in cannot wait for the address either: a start that finds it
// missing fails at once and Restart=on-failure brings it up (see the next test).
func TestDropInDoesNotOrderAfterATargetThePackagedUnitOrdersBefore(t *testing.T) {
	raw, err := os.ReadFile(filepath.Join(moduleDir, "files", "mesh.conf"))
	if err != nil {
		t.Fatal(err)
	}
	forbidden := []string{"network-online.target", "nss-lookup.target"}
	for n, line := range strings.Split(string(raw), "\n") {
		line = strings.TrimSpace(line)
		if strings.HasPrefix(line, "#") {
			continue
		}
		key, val, ok := strings.Cut(line, "=")
		key, val = strings.TrimSpace(key), strings.TrimSpace(val)
		if !ok || (key != "After" && key != "Requires" && key != "Wants" && key != "BindsTo") {
			continue
		}
		for _, target := range forbidden {
			if strings.Contains(val, target) {
				t.Errorf("mesh.conf line %d: %s=%s orders dnsmasq after a target its packaged unit orders itself before: a cycle", n+1, key, val)
			}
		}
	}
}

// The wait for the address in ExecStartPre is at most two seconds: the tunnel that brings the address is ordered
// after network-online.target, which the resolver is ordered before, so a longer wait would hold the tunnel back.
func TestAddressWaitIsAtMostTwoSeconds(t *testing.T) {
	raw, err := os.ReadFile(filepath.Join(moduleDir, "files", "mesh.conf"))
	if err != nil {
		t.Fatal(err)
	}
	found := false
	for _, line := range strings.Split(string(raw), "\n") {
		line = strings.TrimSpace(line)
		if !strings.HasPrefix(line, "ExecStartPre=") {
			continue
		}
		m := regexp.MustCompile(`seq 1 (\d+)`).FindStringSubmatch(line)
		if m == nil {
			t.Fatalf("ExecStartPre has no bounded wait (seq 1 N): %s", line)
		}
		found = true
		if n, _ := strconv.Atoi(m[1]); n > 2 {
			t.Errorf("ExecStartPre waits up to %d s for the address, more than 2 s", n)
		}
	}
	if !found {
		t.Fatal("mesh.conf has no ExecStartPre")
	}
}