package policy_test

import (
	"bytes"
	"context"
	"encoding/json"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"github.com/netkingdom/flex-auth/internal/policy"
	"github.com/netkingdom/flex-auth/pkg/api"
)

func TestInformedDecisionAttributeAdmission(t *testing.T) {
	pkg, err := policy.LoadAndValidateFile(context.Background(), sittingPolicyPath(t))
	if err != nil {
		t.Fatalf("LoadAndValidateFile: %v", err)
	}
	if !pkg.Valid {
		t.Fatalf("package invalid: %+v", pkg.Validation)
	}
	if pkg.Metadata.Version != "v11" {
		t.Fatalf("version = %s; want v11", pkg.Metadata.Version)
	}
	if strings.Contains(pkg.RegoModule, "view_hash") {
		t.Fatal("rule module reads view_hash")
	}
	if !strings.Contains(pkg.RegoModule, "admitted_submitters := set()") || !strings.Contains(pkg.RegoModule, "admitted_classes := set()") {
		t.Fatal("shipped admitted sets are not empty")
	}

	raw, err := os.ReadFile(filepath.Join(sittingDir(t), "attribute_admission_v8.json"))
	if err != nil {
		t.Fatal(err)
	}
	var doc struct {
		PolicyVersion string `json:"policy_version"`
		Cases         []struct {
			ID        string                  `json:"id"`
			Kind      string                  `json:"kind"`
			Assurance string                  `json:"assurance"`
			Request   api.CheckRequest        `json:"request"`
			Expect    api.DecisionExpectation `json:"expect"`
		} `json:"cases"`
	}
	if err := json.Unmarshal(raw, &doc); err != nil {
		t.Fatal(err)
	}
	if doc.PolicyVersion != "v11" {
		t.Fatalf("fixture policy_version = %s", doc.PolicyVersion)
	}
	exactKeys := map[string]bool{"memo_version": true, "approval_id": true, "approval_binding_digest": true}
	attributeKeys := map[string]bool{
		"review_group": true, "memo_class": true, "intake_submitter": true,
		"approval_requester": true, "approval_human_control": true, "memo_version": true,
		"approval_id": true, "approval_binding_digest": true,
	}
	for _, fixture := range doc.Cases {
		request := fixture.Request
		stampAssurance(t, &request, fixture.Assurance)
		if _, ok := request.Context["view_hash"]; ok {
			t.Fatalf("%s carries view_hash", fixture.ID)
		}
		switch fixture.Kind {
		case "exact":
			assertKeys(t, fixture.ID, request.Context, exactKeys)
		case "attribute":
			assertKeys(t, fixture.ID, request.Context, attributeKeys)
		default:
			t.Fatalf("%s kind %q", fixture.ID, fixture.Kind)
		}
		got, err := pkg.Evaluate(context.Background(), request)
		if err != nil {
			t.Fatalf("%s: %v", fixture.ID, err)
		}
		if got.Effect != fixture.Expect.Effect || got.Reason != fixture.Expect.Reason {
			t.Fatalf("%s: got %s %s; want %s %s", fixture.ID, got.Effect, got.Reason, fixture.Expect.Effect, fixture.Expect.Reason)
		}
		if fixture.ID == "exact-record-allow" {
			withHash := request
			withHash.Context = copyContext(request.Context)
			withHash.Context["view_hash"] = "sha256:bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"
			hashed, err := pkg.Evaluate(context.Background(), withHash)
			if err != nil {
				t.Fatal(err)
			}
			if hashed.Effect != got.Effect || hashed.Reason != got.Reason {
				t.Fatalf("view_hash changed exact decision to %s %s", hashed.Effect, hashed.Reason)
			}
		}
	}
}

func TestSittingImagePinMatchesRecordedBuild(t *testing.T) {
	raw, err := os.ReadFile(filepath.Join(repoRoot(t), "values", "informed-decision-sitting.yaml"))
	if err != nil {
		t.Fatal(err)
	}
	text := string(raw)
	// values/informed-decision-sitting.yaml records the v11 image of 1aae59f.
	// The earlier v10 pin (58026ea) is no longer the baseline.
	if !strings.Contains(text, "sha256:feae06d5cd6c68296437d9df344ab76e44c178b8671ac76bf2d6e83e8ac1f645") {
		t.Fatal("sitting image digest differs from the recorded v11 build")
	}
	if !strings.Contains(text, "/opt/flex-auth/examples/informed-decision-sitting/policy.md") {
		t.Fatal("sitting policy path changed")
	}
}

func TestAdmissionSetGenerator(t *testing.T) {
	root := repoRoot(t)
	check := exec.Command("python3", "tools/gen_informed_decision_admission.py", "--check")
	check.Dir = root
	if out, err := check.CombinedOutput(); err != nil {
		t.Fatalf("drift check: %v\n%s", err, out)
	}

	dir := t.TempDir()
	policyPath := filepath.Join(dir, "policy.md")
	shipped := sittingPolicyPath(t)
	source, err := os.ReadFile(shipped)
	if err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(policyPath, source, 0o644); err != nil {
		t.Fatal(err)
	}
	registry := filepath.Join(dir, "submitters.json")
	body := `{
	  "system:serviceaccount:state-hub:state-hub": {
	    "submitter_id": "state-hub",
	    "memo_classes": ["credential-lane", "adr-accept"],
	    "review_groups": ["net-kingdom-admins"],
	    "daily_limit": 1
	  }
	}`
	if err := os.WriteFile(registry, []byte(body), 0o644); err != nil {
		t.Fatal(err)
	}
	drift := exec.Command("python3", filepath.Join(root, "tools/gen_informed_decision_admission.py"),
		"--source", registry, "--policy", policyPath, "--check")
	if err := drift.Run(); err == nil {
		t.Fatal("non-empty registry matched the empty shipped sets")
	}
	after, err := os.ReadFile(policyPath)
	if err != nil {
		t.Fatal(err)
	}
	if !bytes.Equal(after, source) {
		t.Fatal("--check wrote the policy")
	}

	write := exec.Command("python3", filepath.Join(root, "tools/gen_informed_decision_admission.py"),
		"--source", registry, "--policy", policyPath)
	if out, err := write.CombinedOutput(); err != nil {
		t.Fatalf("generate: %v\n%s", err, out)
	}
	generated, err := os.ReadFile(policyPath)
	if err != nil {
		t.Fatal(err)
	}
	text := string(generated)
	if !strings.Contains(text, `"adr-accept",`) || !strings.Contains(text, `"credential-lane",`) || !strings.Contains(text, `"state-hub",`) {
		t.Fatalf("generated sets missing:\n%s", text)
	}
	if !bytes.Equal(mustRead(t, shipped), source) {
		t.Fatal("generator wrote the shipped policy")
	}
	again := exec.Command("python3", filepath.Join(root, "tools/gen_informed_decision_admission.py"),
		"--source", registry, "--policy", policyPath, "--check")
	if out, err := again.CombinedOutput(); err != nil {
		t.Fatalf("regenerated policy drifted: %v\n%s", err, out)
	}

	bad := filepath.Join(dir, "bad.json")
	if err := os.WriteFile(bad, []byte("[]"), 0o644); err != nil {
		t.Fatal(err)
	}
	refused := exec.Command("python3", filepath.Join(root, "tools/gen_informed_decision_admission.py"),
		"--source", bad, "--policy", policyPath)
	if err := refused.Run(); err == nil {
		t.Fatal("malformed registry was accepted")
	}
	kept, err := os.ReadFile(policyPath)
	if err != nil {
		t.Fatal(err)
	}
	if !bytes.Equal(kept, generated) {
		t.Fatal("refused generate changed the policy")
	}
}

func stampAssurance(t *testing.T, request *api.CheckRequest, mode string) {
	t.Helper()
	assurance, _ := request.Subject.Attributes["assurance"].(map[string]any)
	if assurance == nil {
		t.Fatal("assurance missing")
	}
	switch mode {
	case "now":
		assurance["at"] = time.Now().Unix()
	case "stale":
		assurance["at"] = int64(1)
	default:
		t.Fatalf("assurance mode %q", mode)
	}
}

func assertKeys(t *testing.T, id string, ctx map[string]any, want map[string]bool) {
	t.Helper()
	if len(ctx) != len(want) {
		t.Fatalf("%s context keys = %v", id, ctx)
	}
	for key := range want {
		if _, ok := ctx[key]; !ok {
			t.Fatalf("%s missing %s", id, key)
		}
	}
}

func copyContext(in map[string]any) map[string]any {
	out := make(map[string]any, len(in)+1)
	for key, value := range in {
		out[key] = value
	}
	return out
}

func sittingDir(t *testing.T) string {
	t.Helper()
	return filepath.Join(repoRoot(t), "examples", "informed-decision-sitting")
}

func sittingPolicyPath(t *testing.T) string {
	t.Helper()
	return filepath.Join(sittingDir(t), "policy.md")
}

func repoRoot(t *testing.T) string {
	t.Helper()
	return filepath.Join("..", "..")
}

func mustRead(t *testing.T, path string) []byte {
	t.Helper()
	data, err := os.ReadFile(path)
	if err != nil {
		t.Fatal(err)
	}
	return data
}