package main

import (
	"encoding/json"
	"errors"
	"net/url"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"
)

// The grant entry's shape is the mesh's Contribution (mesh-sdk go/catalogue/declaration.go: from, node, as, values,
// derived), written in a `given` list by receivedFile in the same file; `shares` is written into values by
// go/catalogue/bucket_shares.go withShares: [{"to": ..., "methods": [...]}].
const grantFile = `{
  "contributions": 1,
  "requirement": "s3-bucket",
  "given": [
    {"from": "brother", "node": "shanks", "as": "brother-key",
     "values": {"shares": [{"to": "seat:node-files", "methods": ["put"]}, {"to": "print-and-scan", "methods": ["get"]}]},
     "derived": {"bucket": "mesh-shanks-brother"}},
    {"from": "nextcloud", "node": "novox", "as": "nextcloud-key", "derived": {"bucket": "mesh-novox-nextcloud"}}
  ]
}`

// The seats answer is the controller's (mesh-controller.seats read on 2026-10-21): seats[].holders[] of {node, module},
// and outside[] of {Claim, Node, Module}.
const seatsAnswer = `{"answer": {"seats": [
  {"seat": "node-files", "scope": "node", "holders": [{"node": "g14", "module": "mesh-files"}, {"node": "shanks", "module": "mesh-files"}]},
  {"seat": "node-backup", "scope": "node", "holders": [{"node": "g14", "module": "restic"}]}
 ], "outside": [{"Claim": "printer", "Scope": "mesh", "Node": "shanks", "Module": "brother", "Site": "home", "Kind": ""}]}}`

type rig struct {
	s          *server
	dir        string
	now        time.Time
	seatsCalls int
	seatsErr   error
}

func newRig(t *testing.T) *rig {
	t.Helper()
	dir := t.TempDir()
	r := &rig{dir: dir, now: time.Date(2026, 10, 21, 12, 0, 0, 0, time.UTC)}
	write := func(name, content string) string {
		p := filepath.Join(dir, name)
		if err := os.MkdirAll(filepath.Dir(p), 0o700); err != nil {
			t.Fatal(err)
		}
		if err := os.WriteFile(p, []byte(content), 0o600); err != nil {
			t.Fatal(err)
		}
		return p
	}
	// What the mesh renders from files/object-store.json for a store on novox.internal, port 20001.
	cfg := write("object-store.json", `{"scheme":"http","at":"novox.internal","port":"20001","region":"eu-west"}`)
	write("links/mesh-shanks-brother.secret", "brother-link-secret\n")
	write("links/mesh-novox-nextcloud.secret", "nextcloud-link-secret\n")
	grants := write("grants/mesh.json", grantFile)
	s, err := newServer(cfg, filepath.Join(dir, "links"), grants)
	if err != nil {
		t.Fatal(err)
	}
	s.now = func() time.Time { return r.now }
	s.seats = func() (json.RawMessage, error) {
		r.seatsCalls++
		if r.seatsErr != nil {
			return nil, r.seatsErr
		}
		return json.RawMessage(seatsAnswer), nil
	}
	r.s = s
	return r
}

func ask(bucket, method string, seconds any) map[string]any {
	a := map[string]any{"bucket": bucket, "key": "doc.pdf", "method": method}
	if seconds != nil {
		a["seconds"] = seconds
	}
	return a
}

func linkOf(t *testing.T, got any) *url.URL {
	t.Helper()
	m := got.(map[string]any)
	u, err := url.Parse(m["link"].(string))
	if err != nil {
		t.Fatal(err)
	}
	return u
}

// 1516/AC1: brother's own ask gets a link signed with the bucket's link key, for the store's host and port, 300 s.
func TestLinkIsSignedWithTheBucketsLinkKey(t *testing.T) {
	r := newRig(t)
	got, err := r.s.link("shanks.brother", ask("mesh-shanks-brother", "get", float64(300)))
	if err != nil {
		t.Fatal(err)
	}
	u := linkOf(t, got)
	if u.Host != "novox.internal:20001" || u.Scheme != "http" || u.Path != "/mesh-shanks-brother/doc.pdf" {
		t.Fatalf("link goes to %s", u)
	}
	q := u.Query()
	if cred := q.Get("X-Amz-Credential"); !strings.HasPrefix(cred, linkKeyID("mesh-shanks-brother")+"/20261021/eu-west/s3/") {
		t.Fatalf("credential %q is not the bucket's link key", cred)
	}
	if strings.Contains(u.String(), "meshroot") {
		t.Fatal("the root account signed a link")
	}
	if q.Get("X-Amz-Expires") != "300" || q.Get("X-Amz-Date") != "20261021T120000Z" {
		t.Fatalf("expiry %q at %q", q.Get("X-Amz-Expires"), q.Get("X-Amz-Date"))
	}
}

// 1516/AC1: the link key id is the one the provisioner makes (modules/minio/links.ts linkKeyId, tested there with the
// same literal).
func TestLinkKeyIDMatchesTheProvisioners(t *testing.T) {
	if got := linkKeyID("brother"); got != "link0b4bd77cec705cf5" {
		t.Fatalf("linkKeyID = %s", got)
	}
}

// 1516/AC2: a share to seat:node-files for put, mesh-files holding node-files on g14: put given, get refused naming the method.
func TestSeatShareGivesTheHoldersTheSharedMethodOnly(t *testing.T) {
	r := newRig(t)
	if _, err := r.s.link("g14.mesh-files", ask("mesh-shanks-brother", "put", nil)); err != nil {
		t.Fatalf("put: %v", err)
	}
	_, err := r.s.link("g14.mesh-files", ask("mesh-shanks-brother", "get", nil))
	if err == nil || !strings.Contains(err.Error(), "put, not get") {
		t.Fatalf("get was not refused naming the method: %v", err)
	}
	// A module share is judged by name alone.
	if _, err := r.s.link("novox.print-and-scan", ask("mesh-shanks-brother", "get", nil)); err != nil {
		t.Fatalf("print-and-scan get: %v", err)
	}
}

// 1516/AC3: each of these is refused with its reason.
func TestRefusals(t *testing.T) {
	r := newRig(t)
	cases := []struct {
		name, caller string
		args         map[string]any
		want         string
	}{
		{"a stranger", "g14.restic", ask("mesh-shanks-brother", "get", nil), "not the bucket's consumer"},
		{"a seat it does not hold", "g14.restic", ask("mesh-shanks-brother", "put", nil), "not the bucket's consumer"},
		{"unproven", "unproven", ask("mesh-shanks-brother", "get", nil), "did not prove"},
		{"no grant", "shanks.brother", ask("no-such-bucket", "get", nil), "no grant names bucket"},
		{"seconds over 600", "shanks.brother", ask("mesh-shanks-brother", "get", float64(601)), "at most ten minutes"},
		{"seconds zero", "shanks.brother", ask("mesh-shanks-brother", "get", float64(0)), "outside 1 to 600"},
		{"method delete", "shanks.brother", ask("mesh-shanks-brother", "delete", nil), "not get or put"},
		{"another consumer's bucket", "shanks.brother", ask("mesh-novox-nextcloud", "get", nil), "not the bucket's consumer"},
	}
	for _, c := range cases {
		_, err := r.s.link(c.caller, c.args)
		if err == nil || !strings.Contains(err.Error(), c.want) {
			t.Errorf("%s: want a refusal containing %q, got %v", c.name, c.want, err)
		}
	}
}

// 1516/AC4: with the controller unreadable a seat share is refused naming why; a good read serves a second ask within
// 60 s from the cache and is read again after.
func TestSeatsUnreadableAndCached(t *testing.T) {
	r := newRig(t)
	r.seatsErr = errors.New("the controller did not answer")
	_, err := r.s.link("g14.mesh-files", ask("mesh-shanks-brother", "put", nil))
	if err == nil || !strings.Contains(err.Error(), "the controller did not answer") || !strings.Contains(err.Error(), "node-files") {
		t.Fatalf("not refused naming why: %v", err)
	}
	r.seatsErr = nil
	put := func() {
		t.Helper()
		if _, err := r.s.link("g14.mesh-files", ask("mesh-shanks-brother", "put", nil)); err != nil {
			t.Fatal(err)
		}
	}
	put() // a failed read is not cached: this reads again
	put() // served from the cache
	if r.seatsCalls != 2 {
		t.Fatalf("the controller was asked %d times, want 2 (one failure, one good read)", r.seatsCalls)
	}
	r.now = r.now.Add(59 * time.Second)
	put()
	if r.seatsCalls != 2 {
		t.Fatalf("an ask within 60 s read the seats again (%d calls)", r.seatsCalls)
	}
	r.now = r.now.Add(2 * time.Second)
	put()
	if r.seatsCalls != 3 {
		t.Fatalf("the seats were not read again after 60 s (%d calls)", r.seatsCalls)
	}
}

// 1516/AC5: the grant file is read at each call.
func TestGrantFileIsReadAtEachCall(t *testing.T) {
	r := newRig(t)
	if _, err := r.s.link("novox.print-and-scan", ask("mesh-shanks-brother", "get", nil)); err != nil {
		t.Fatal(err)
	}
	changed := strings.Replace(grantFile, `{"to": "print-and-scan", "methods": ["get"]}`, `{"to": "someone-else", "methods": ["get"]}`, 1)
	if err := os.WriteFile(r.s.receives, []byte(changed), 0o600); err != nil {
		t.Fatal(err)
	}
	if _, err := r.s.link("novox.print-and-scan", ask("mesh-shanks-brother", "get", nil)); err == nil {
		t.Fatal("the second call judged by the old shares")
	}
	if _, err := r.s.link("novox.someone-else", ask("mesh-shanks-brother", "get", nil)); err != nil {
		t.Fatal(err)
	}
}