package api

import (
	"encoding/json"
	"errors"
	"net/http"
	"strings"
	"testing"

	"github.com/loyaly/behavision-server/internal/auth"
)

// enrol runs a real enrolment and returns the agent's own API token.
func enrol(t *testing.T, s *Server, fs *fakeStore) string {
	t.Helper()
	code := "ABCDEF-123456"
	fs.enrolment[hashHex(code)] = Enrolment{
		ClientID: "client-acme", AgentID: "agent-1", SiteID: "site-1",
		SiteName: "Chennai", SiteSlug: "store1",
		MQTTUser: "acme.store1", MQTTPass: "broker-secret",
	}
	rec := do(t, s, "POST", "/api/agent/enrol", "", map[string]string{"site_token": code})
	if rec.Code != http.StatusOK {
		t.Fatalf("enrol failed: %d %s", rec.Code, rec.Body.String())
	}
	var got map[string]any
	json.Unmarshal(rec.Body.Bytes(), &got) //nolint:errcheck
	tok, _ := got["agent_token"].(string)
	if tok == "" {
		t.Fatal("enrolment did not return an agent token")
	}
	return tok
}

func TestEnrolmentIssuesAnAgentTokenSeparateFromTheBrokerPassword(t *testing.T) {
	s, fs := newServer(t)
	tok := enrol(t, s, fs)
	// Two secrets for two different questions: the broker password says this
	// site may publish events, the agent token says it may ask the API for
	// something. One secret for both means rotating either breaks the other.
	if tok == "broker-secret" {
		t.Fatal("the agent token is the broker password")
	}
	if _, err := fs.AgentByToken(t.Context(), auth.HashToken(tok)); err != nil {
		t.Fatalf("the issued token does not authenticate: %v", err)
	}
}

func TestUploadURLRequiresAnEnrolledAgent(t *testing.T) {
	s, fs := newServer(t)
	s.Blob = &fakeBlob{}
	seedUser(fs)

	if rec := do(t, s, "POST", "/api/agent/upload-url", "", nil); rec.Code != http.StatusUnauthorized {
		t.Fatalf("unauthenticated upload-url returned %d", rec.Code)
	}
	if rec := do(t, s, "POST", "/api/agent/upload-url", "not-a-token", nil); rec.Code != http.StatusUnauthorized {
		t.Fatalf("a bogus agent token was accepted: %d", rec.Code)
	}
	// A staff session is not an agent. The two are authenticated differently
	// and must not be interchangeable.
	sess := login(t, s, "manager@acme.com", "correct horse battery")
	if rec := do(t, s, "POST", "/api/agent/upload-url", sess.Token, nil); rec.Code != http.StatusUnauthorized {
		t.Fatalf("a user session was accepted as an agent: %d", rec.Code)
	}
}

// The server picks the key from the credential the request authenticated with.
// A caller-supplied key would let one site overwrite another's images, which is
// the entire reason uploads are presigned instead of shipping a bucket password.
func TestTheServerChoosesTheKeyNotTheAgent(t *testing.T) {
	s, fs := newServer(t)
	blob := &fakeBlob{}
	s.Blob = blob
	tok := enrol(t, s, fs)

	rec := do(t, s, "POST", "/api/agent/upload-url", tok,
		map[string]string{"content_type": "image/jpeg"})
	if rec.Code != http.StatusOK {
		t.Fatalf("got %d: %s", rec.Code, rec.Body.String())
	}
	var target UploadTarget
	json.Unmarshal(rec.Body.Bytes(), &target) //nolint:errcheck

	if !strings.HasPrefix(target.Key, "behavision/acme/store1/") {
		t.Fatalf("key is not namespaced to the authenticated site: %q", target.Key)
	}
	// The ACL must be handed back for the agent to send, because it is inside
	// the signature: the shop PC cannot decide to publish the image instead.
	if target.Headers["x-amz-acl"] != "private" {
		t.Fatalf("upload does not force a private ACL: %v", target.Headers)
	}
	if target.URL == "" || target.ExpiresIn <= 0 {
		t.Fatalf("incomplete upload target: %+v", target)
	}

	// Two requests must not collide on one object.
	rec2 := do(t, s, "POST", "/api/agent/upload-url", tok, nil)
	var second UploadTarget
	json.Unmarshal(rec2.Body.Bytes(), &second) //nolint:errcheck
	if second.Key == target.Key {
		t.Fatal("two uploads were given the same key")
	}
}

func TestUploadIsRefusedCleanlyWhenImagesAreOff(t *testing.T) {
	s, fs := newServer(t)
	s.Blob = nil // the default: this product stores no images unless told to
	tok := enrol(t, s, fs)

	rec := do(t, s, "POST", "/api/agent/upload-url", tok, nil)
	// 501, not 500: the agent should carry on sending visits without a photo
	// rather than treating this as a failure to retry.
	if rec.Code != http.StatusNotImplemented {
		t.Fatalf("got %d, want 501", rec.Code)
	}
}

func TestVisitorImageIsAShortLivedLinkAndIsAudited(t *testing.T) {
	s, fs := newServer(t)
	blob := &fakeBlob{}
	s.Blob = blob
	seedUser(fs)
	fs.imageKeys[visitorAID] = "behavision/acme/store1/2026/08/31/abc.jpg"
	sess := login(t, s, "manager@acme.com", "correct horse battery")

	rec := do(t, s, "GET", visitorA+"/image", sess.Token, nil)
	if rec.Code != http.StatusOK {
		t.Fatalf("got %d: %s", rec.Code, rec.Body.String())
	}
	var body map[string]any
	json.Unmarshal(rec.Body.Bytes(), &body) //nolint:errcheck
	url, _ := body["url"].(string)
	if !strings.Contains(url, "X-Amz-Signature") {
		t.Fatalf("not a presigned link: %q", url)
	}
	if body["expires_in"] == nil {
		t.Fatal("the caller is not told the link expires")
	}
	// Every read of a face image is worth a row: "who looked at my customers"
	// needs an answer that is not a guess.
	var audited bool
	for _, a := range fs.audits {
		if a.Action == "image.view" && a.EntityID == visitorAID {
			audited = true
		}
	}
	if !audited {
		t.Fatalf("viewing a face image was not audited: %+v", fs.audits)
	}
}

func TestAnotherTenantsImageIsNotFound(t *testing.T) {
	s, fs := newServer(t)
	s.Blob = &fakeBlob{}
	seedUser(fs)
	// The store scopes by client, so a foreign id simply has no key.
	sess := login(t, s, "manager@acme.com", "correct horse battery")
	rec := do(t, s, "GET", "/api/visitors/"+visitorB+"/image", sess.Token, nil)
	if rec.Code != http.StatusNotFound {
		t.Fatalf("got %d, want 404", rec.Code)
	}
}

// -- erasure ----------------------------------------------------------------

func TestErasureDeletesTheImageBeforeTheDatabaseRow(t *testing.T) {
	s, fs := newServer(t)
	blob := &fakeBlob{}
	s.Blob = blob
	seedUser(fs)
	key := "behavision/acme/store1/2026/08/31/abc.jpg"
	fs.imageKeys[visitorAID] = key
	sess := login(t, s, "manager@acme.com", "correct horse battery")

	rec := do(t, s, "DELETE", visitorA, sess.Token, nil)
	if rec.Code != http.StatusNoContent {
		t.Fatalf("got %d: %s", rec.Code, rec.Body.String())
	}
	if len(blob.deleted) != 1 || blob.deleted[0] != key {
		t.Fatalf("the face image was not deleted from storage: %v", blob.deleted)
	}
	if len(fs.forgotten) != 1 || fs.forgotten[0] != visitorAID {
		t.Fatalf("the database record was not erased: %v", fs.forgotten)
	}
}

// If the object delete fails and the row is erased anyway, the keys are gone
// and nothing knows which files to remove - the image outlives the request with
// no record that it should not. Reporting success there is the one outcome this
// endpoint must never produce.
func TestAFailedImageDeleteAbortsTheWholeErasure(t *testing.T) {
	s, fs := newServer(t)
	blob := &fakeBlob{failNext: errors.New("bucket unreachable")}
	s.Blob = blob
	seedUser(fs)
	fs.imageKeys[visitorAID] = "behavision/acme/store1/2026/08/31/abc.jpg"
	sess := login(t, s, "manager@acme.com", "correct horse battery")

	rec := do(t, s, "DELETE", visitorA, sess.Token, nil)
	if rec.Code != http.StatusBadGateway {
		t.Fatalf("got %d, want 502", rec.Code)
	}
	if len(fs.forgotten) != 0 {
		t.Fatal("the database row was erased while the photo survived")
	}
	// And the operator is told to retry rather than believing it is done.
	if !strings.Contains(strings.ToLower(rec.Body.String()), "try again") {
		t.Fatalf("unhelpful message: %s", rec.Body.String())
	}
}

func TestOnlyManagersAndAboveCanErase(t *testing.T) {
	s, fs := newServer(t)
	s.Blob = &fakeBlob{}
	fs.addUser("shopfloor@acme.com", "correct horse battery", UserRecord{
		ID: "u7", ClientID: "client-acme", Role: "staff", Active: true,
	})
	sess := login(t, s, "shopfloor@acme.com", "correct horse battery")
	// Staff fill in the customer form; destroying a record is a different
	// decision with a different blast radius.
	if rec := do(t, s, "DELETE", visitorA, sess.Token, nil); rec.Code != http.StatusForbidden {
		t.Fatalf("staff could erase a customer: %d", rec.Code)
	}
}

func TestErasureWithNoImageStillErasesTheRecord(t *testing.T) {
	s, fs := newServer(t)
	s.Blob = &fakeBlob{}
	seedUser(fs)
	sess := login(t, s, "manager@acme.com", "correct horse battery")

	// Most visitors have no photo. Erasure must not depend on there being one.
	if rec := do(t, s, "DELETE", visitorA, sess.Token, nil); rec.Code != http.StatusNoContent {
		t.Fatalf("got %d: %s", rec.Code, rec.Body.String())
	}
	if len(fs.forgotten) != 1 {
		t.Fatalf("record not erased: %v", fs.forgotten)
	}
}