package facts

import (
	"fmt"
	"net"
	"regexp"
	"strings"
	"testing"
	"time"
)

// A pseudonym keeps what a limit meets — the length, and letters where letters were — and nothing else.
func TestAPseudonymKeepsTheLengthAndShapeAndIsStable(t *testing.T) {
	for _, name := range []string{"ace", "g14", "novox", "shanks", "home-server", "a"} {
		p := Pseudonym("machine", name)
		if len(p) != len(name) {
			t.Errorf("%s became %s: %d characters for %d", name, p, len(p), len(name))
		}
		if p == name {
			t.Errorf("%s was kept as itself", name)
		}
		if p != Pseudonym("machine", name) {
			t.Errorf("%s is not stable", name)
		}
		for i := range name {
			isLetter := func(c byte) bool { return c >= 'a' && c <= 'z' }
			isDigit := func(c byte) bool { return c >= '0' && c <= '9' }
			if isLetter(name[i]) != isLetter(p[i]) || isDigit(name[i]) != isDigit(p[i]) {
				t.Errorf("%s became %s: the shape moved at %d", name, p, i)
			}
		}
	}
	if Pseudonym("machine", "ace") == Pseudonym("site", "ace") {
		t.Error("a site and a machine of one name share a pseudonym, so a snapshot says they are one thing")
	}
}

// Nothing of the installation survives the scrubber: names, domains, accounts, addresses, mail, secrets.
func TestTheScrubberLeavesNothingOfTheInstallation(t *testing.T) {
	s := NewScrubber()
	machine := s.Machine("homeserver")
	s.Account("jochens")
	domain := s.Domain("zurag.be")
	if len(domain) != len("zurag.be") || !strings.HasSuffix(domain, ".be") || domain == "zurag.be" {
		t.Errorf("the domain became %q", domain)
	}
	in := map[string]any{
		"hub":        "homeserver",
		"listen":     "10.42.0.7:51820",
		"upstream":   []any{"192.168.1.135", "fd00::1"},
		"site":       "https://grafana.zurag.be/login",
		"admin":      "jschoubben@gmail.com",
		"home":       "/home/jochens/.ssh",
		"api_key":    "sk-live-abcdef",
		"nested":     map[string]any{"password": "hunter2", "port": float64(5432)},
		"opaque":     "a8F3kQ9zL2mX7vB4nC6dE1rT5yU0iO8pA3sD",
		"dsn":        "postgres://app:s3cr3tpass@db.internal:5432/app",
		"pem":        "-----BEGIN PRIVATE KEY-----\nMIIB",
		"plain":      "a-long-plain-module-directory-name",
		"digest":     "sha256:44136fa355b3678a1146ad16f7e8649e94fb4fc21fe77e8310c060f61caaff8a",
		"version":    "2.11.17",
		"homeserver": true,
	}
	out := s.Values(in)
	flat := flatten(out)
	for _, leaked := range []string{"homeserver\"", "10.42.0.7", "192.168.1.135", "fd00::1", "zurag", "jschoubben",
		"gmail", "jochens", "sk-live", "hunter2", "a8F3kQ9zL2mX7vB4nC6dE1rT5yU0iO8pA3sD", "s3cr3tpass", "MIIB"} {
		if strings.Contains(flat, leaked) {
			t.Errorf("%q survived the scrubber:\n%s", leaked, flat)
		}
	}
	if out["hub"] != machine {
		t.Errorf("a machine named in a setting became %v, not its pseudonym %s", out["hub"], machine)
	}
	for _, kept := range []string{"a-long-plain-module-directory-name", "2.11.17", "sha256:44136fa3", "5432"} {
		if !strings.Contains(flat, kept) {
			t.Errorf("%q was scrubbed, and it is not the installation's:\n%s", kept, flat)
		}
	}
	// Every address left is a documentation address.
	for _, a := range regexp.MustCompile(`[0-9a-f:.]{7,}`).FindAllString(flat, -1) {
		ip := net.ParseIP(strings.Trim(a, ".:"))
		if ip == nil {
			continue
		}
		doc := false
		for _, cidr := range []string{"192.0.2.0/24", "198.51.100.0/24", "203.0.113.0/24", "2001:db8::/32"} {
			_, n, _ := net.ParseCIDR(cidr)
			doc = doc || n.Contains(ip)
		}
		if !doc {
			t.Errorf("%s is not a documentation address", a)
		}
	}
	// The same address is always the same stand-in.
	if s.Text("10.42.0.7") != s.Text("at 10.42.0.7")[3:] {
		t.Error("one address became two stand-ins")
	}
}

func flatten(v any) string {
	var b strings.Builder
	var walk func(any)
	walk = func(v any) {
		switch t := v.(type) {
		case map[string]any:
			for k, e := range t {
				b.WriteString(k + "\"=")
				walk(e)
				b.WriteString("\n")
			}
		case []any:
			for _, e := range t {
				walk(e)
				b.WriteString(",")
			}
		case string:
			b.WriteString(t + "\"")
		default:
			b.WriteString(fmt.Sprint(t))
		}
	}
	walk(v)
	return b.String()
}

// Two snapshots of one mesh, taken apart, are one content.
func TestASnapshotOfAnUnchangedMeshIsTheSameContentAnotherDay(t *testing.T) {
	f := Facts{Format: Format, Taken: time.Now(), Machines: []Machine{{Name: "b"}, {Name: "a"}}}
	g := f
	g.Taken = f.Taken.Add(24 * time.Hour)
	g.Machines = []Machine{{Name: "a"}, {Name: "b"}}
	a, err := f.Content()
	if err != nil {
		t.Fatal(err)
	}
	b, _ := g.Content()
	if a != b {
		t.Error("the same mesh a day later reads as a change")
	}
	g.Machines = append(g.Machines, Machine{Name: "c"})
	if c, _ := g.Content(); c == a {
		t.Error("a machine added reads as no change")
	}
}

// A reader refuses a snapshot it cannot read whole.
func TestANewerSnapshotIsRefusedNotHalfRead(t *testing.T) {
	if _, err := Decode([]byte(`{"facts": 99}`)); err == nil || !strings.Contains(err.Error(), "newer controller") {
		t.Errorf("a newer format read as %v", err)
	}
	if _, err := Decode([]byte(`{"machines": []}`)); err == nil {
		t.Error("a document with no format read as a snapshot")
	}
	f, err := Decode([]byte(`{"facts": 1, "machines": [{"name": "abc", "length": 3}, {"name": "defgh", "length": 5}]}`))
	if err != nil || f.Longest() != 5 {
		t.Errorf("read %+v, %v", f, err)
	}
}