package main

import (
	"bytes"
	"context"
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"regexp"
	"sort"
	"strings"
	"testing"

	"gopkg.in/yaml.v3"

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

// The ops-warden secret-read pin (CUST-WP-0075, bug b792c5d0): warden's
// check_fetch_policy sends action read on resource type secret with
// resource.system = the lane's owner_repo.

const opsWardenPrincipal = "system:serviceaccount:ops-warden:ops-warden"

func fetchPath(name string) string {
	return filepath.Join("..", "..", "examples", "ops-warden-fetch", name)
}

func loadFetchRequest(t *testing.T, name string) api.CheckRequest {
	t.Helper()
	raw, err := os.ReadFile(fetchPath(name))
	if err != nil {
		t.Fatal(err)
	}
	var request api.CheckRequest
	if err := json.Unmarshal(raw, &request); err != nil {
		t.Fatalf("%s: %v", name, err)
	}
	return request
}

func TestOpsWardenFetchDecisions(t *testing.T) {
	engine, err := buildEngine(context.Background(), fetchPath("registry_snapshot.json"), fetchPath("policy_package.md"), "")
	if err != nil {
		t.Fatalf("buildEngine: %v", err)
	}
	cases := []struct {
		file   string
		effect api.DecisionEffect
		reason string
	}{
		{"check_request_allow_forgejo_admin_api_token.json", api.DecisionEffectAllow, "secret_read_lane_matched"},
		{"check_request_allow_openrouter_llm_connect.json", api.DecisionEffectAllow, "secret_read_lane_matched"},
		{"check_request_deny_unknown_need.json", api.DecisionEffectDeny, "unknown_need"},
		{"check_request_deny_wrong_system.json", api.DecisionEffectDeny, "wrong_system"},
		{"check_request_deny_non_secret_type.json", api.DecisionEffectDeny, "wrong_resource_type"},
	}
	for _, tc := range cases {
		t.Run(tc.file, func(t *testing.T) {
			decision, err := engine.Check(context.Background(), loadFetchRequest(t, tc.file))
			if err != nil {
				t.Fatal(err)
			}
			if decision.Effect != tc.effect || decision.Reason != tc.reason {
				t.Fatalf("decision = %s/%s; want %s/%s", decision.Effect, decision.Reason, tc.effect, tc.reason)
			}
			if decision.ID == "" {
				t.Fatal("decision.ID is empty; warden needs a policy_decision_id")
			}
		})
	}
}

// fetchBindings reads the caller bindings exactly as the values file declares
// them, so the test exercises the configuration that would be deployed.
func fetchBindings(t *testing.T) (string, map[string]string) {
	t.Helper()
	raw, err := os.ReadFile(filepath.Join("..", "..", "values", "ops-warden-fetch.yaml"))
	if err != nil {
		t.Fatal(err)
	}
	var values struct {
		CallerAuth struct {
			Mode          string   `yaml:"mode"`
			Binding       string   `yaml:"binding"`
			ExtraBindings []string `yaml:"extraBindings"`
		} `yaml:"callerAuth"`
	}
	if err := yaml.Unmarshal(raw, &values); err != nil {
		t.Fatal(err)
	}
	bindings := map[string]string{}
	for _, pair := range append([]string{values.CallerAuth.Binding}, values.CallerAuth.ExtraBindings...) {
		system, principal, ok := strings.Cut(pair, "=")
		if !ok {
			t.Fatalf("malformed binding %q", pair)
		}
		bindings[system] = principal
	}
	return values.CallerAuth.Mode, bindings
}

func TestOpsWardenFetchCallerBindings(t *testing.T) {
	mode, bindings := fetchBindings(t)
	if mode != "enforce" {
		t.Fatalf("callerAuth.mode = %q; the fetch pin must enforce", mode)
	}
	for system, principal := range bindings {
		if principal != opsWardenPrincipal {
			t.Fatalf("system %q bound to %q; only ops-warden may ask", system, principal)
		}
	}
	engine, err := buildEngine(context.Background(), fetchPath("registry_snapshot.json"), fetchPath("policy_package.md"), "")
	if err != nil {
		t.Fatalf("buildEngine: %v", err)
	}
	serve := func(username string) *httptest.Server {
		authenticator, err := callerauth.New(callerauth.ModeEnforce, fixedTokenReviewer{identity: callerauth.Identity{
			Username:  username,
			Audiences: []string{"flex-auth"},
		}}, "flex-auth", bindings, nil)
		if err != nil {
			t.Fatal(err)
		}
		return httptest.NewServer(newServeMuxWithCallerAuth(engine, authenticator))
	}
	post := func(server *httptest.Server, request api.CheckRequest, token bool) (int, api.DecisionEnvelope) {
		body, _ := json.Marshal(request)
		req, _ := http.NewRequest(http.MethodPost, server.URL+"/v1/check", bytes.NewReader(body))
		req.Header.Set("content-type", "application/json")
		if token {
			req.Header.Set("authorization", "Bearer workload-token")
		}
		resp, err := http.DefaultClient.Do(req)
		if err != nil {
			t.Fatal(err)
		}
		defer resp.Body.Close()
		var envelope api.DecisionEnvelope
		if resp.StatusCode == http.StatusOK {
			if err := json.NewDecoder(resp.Body).Decode(&envelope); err != nil {
				t.Fatal(err)
			}
		}
		return resp.StatusCode, envelope
	}

	warden := serve(opsWardenPrincipal)
	defer warden.Close()
	allow := loadFetchRequest(t, "check_request_allow_forgejo_admin_api_token.json")

	if code, envelope := post(warden, allow, true); code != http.StatusOK || envelope.Effect != api.DecisionEffectAllow {
		t.Fatalf("ops-warden forgejo read = %d %s/%s; want 200 allow", code, envelope.Effect, envelope.Reason)
	}
	if code, _ := post(warden, allow, false); code != http.StatusUnauthorized {
		t.Fatalf("anonymous = %d; want 401", code)
	}
	unbound := allow
	unbound.Resource.System = "secrets-engine"
	unbound.Context = map[string]any{"need_id": "forgejo-admin-api-token", "owner_repo": "secrets-engine"}
	if code, _ := post(warden, unbound, true); code != http.StatusForbidden {
		t.Fatalf("ops-warden on unbound system = %d; want 403", code)
	}

	other := serve("system:serviceaccount:another:caller")
	defer other.Close()
	if code, _ := post(other, allow, true); code != http.StatusForbidden {
		t.Fatalf("wrong caller = %d; want 403", code)
	}
}

// TestOpsWardenFetchRegistryMatchesPolicy keeps the two generated artifacts in
// step: every catalog lane in the package is a registry resource of its owner
// system, and nothing else is. Drift against the catalog itself is
// tools/gen_ops_warden_fetch.py --check (tests/stage1.sh).
func TestOpsWardenFetchRegistryMatchesPolicy(t *testing.T) {
	raw, err := os.ReadFile(fetchPath("policy_package.md"))
	if err != nil {
		t.Fatal(err)
	}
	block := regexp.MustCompile(`(?s)catalog_lanes := \{(.*?)\}`).FindSubmatch(raw)
	if block == nil {
		t.Fatal("catalog_lanes block not found")
	}
	var fromPolicy []string
	for _, m := range regexp.MustCompile(`"([^"]+)": "([^"]+)"`).FindAllSubmatch(block[1], -1) {
		fromPolicy = append(fromPolicy, string(m[2])+"/secret:"+string(m[1]))
	}

	snapRaw, err := os.ReadFile(fetchPath("registry_snapshot.json"))
	if err != nil {
		t.Fatal(err)
	}
	var snap struct {
		ResourceManifests []struct {
			System    string `json:"system"`
			Resources []struct {
				ID string `json:"id"`
			} `json:"resources"`
		} `json:"resource_manifests"`
	}
	if err := json.Unmarshal(snapRaw, &snap); err != nil {
		t.Fatal(err)
	}
	var fromRegistry []string
	for _, manifest := range snap.ResourceManifests {
		for _, resource := range manifest.Resources {
			fromRegistry = append(fromRegistry, manifest.System+"/"+resource.ID)
		}
	}
	sort.Strings(fromPolicy)
	sort.Strings(fromRegistry)
	if len(fromPolicy) == 0 || strings.Join(fromPolicy, ",") != strings.Join(fromRegistry, ",") {
		t.Fatalf("policy lanes %v\nregistry   %v", fromPolicy, fromRegistry)
	}
}