package server

import (
	"bytes"
	"crypto/ed25519"
	"crypto/rand"
	"encoding/json"
	"io"
	"log/slog"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"

	"git.wntrmute.dev/kyle/mcias/internal/auth"
	"git.wntrmute.dev/kyle/mcias/internal/config"
	"git.wntrmute.dev/kyle/mcias/internal/db"
	"git.wntrmute.dev/kyle/mcias/internal/model"
	"git.wntrmute.dev/kyle/mcias/internal/token"
)

const testIssuer = "https://auth.example.com"

func newTestServer(t *testing.T) (*Server, ed25519.PublicKey, ed25519.PrivateKey, *db.DB) {
	t.Helper()

	pub, priv, err := ed25519.GenerateKey(rand.Reader)
	if err != nil {
		t.Fatalf("generate key: %v", err)
	}

	database, err := db.Open(":memory:")
	if err != nil {
		t.Fatalf("open db: %v", err)
	}
	if err := db.Migrate(database); err != nil {
		t.Fatalf("migrate db: %v", err)
	}
	t.Cleanup(func() { _ = database.Close() })

	masterKey := make([]byte, 32)
	if _, err := rand.Read(masterKey); err != nil {
		t.Fatalf("generate master key: %v", err)
	}

	cfg := config.NewTestConfig(testIssuer)

	logger := slog.New(slog.NewTextHandler(io.Discard, nil))
	srv := New(database, cfg, priv, pub, masterKey, logger)
	return srv, pub, priv, database
}

// createTestHumanAccount creates a human account with password "testpass123".
func createTestHumanAccount(t *testing.T, srv *Server, username string) *model.Account {
	t.Helper()
	hash, err := auth.HashPassword("testpass123", auth.ArgonParams{Time: 3, Memory: 65536, Threads: 4})
	if err != nil {
		t.Fatalf("hash password: %v", err)
	}
	acct, err := srv.db.CreateAccount(username, model.AccountTypeHuman, hash)
	if err != nil {
		t.Fatalf("create account: %v", err)
	}
	return acct
}

// issueAdminToken creates an account with admin role, issues a JWT, and tracks it.
func issueAdminToken(t *testing.T, srv *Server, priv ed25519.PrivateKey, username string) (string, *model.Account) {
	t.Helper()
	acct := createTestHumanAccount(t, srv, username)
	if err := srv.db.GrantRole(acct.ID, "admin", nil); err != nil {
		t.Fatalf("grant admin role: %v", err)
	}

	tokenStr, claims, err := token.IssueToken(priv, testIssuer, acct.UUID, []string{"admin"}, time.Hour)
	if err != nil {
		t.Fatalf("issue token: %v", err)
	}
	if err := srv.db.TrackToken(claims.JTI, acct.ID, claims.IssuedAt, claims.ExpiresAt); err != nil {
		t.Fatalf("track token: %v", err)
	}
	return tokenStr, acct
}

func doRequest(t *testing.T, handler http.Handler, method, path string, body interface{}, authToken string) *httptest.ResponseRecorder {
	t.Helper()
	var bodyReader io.Reader
	if body != nil {
		b, err := json.Marshal(body)
		if err != nil {
			t.Fatalf("marshal body: %v", err)
		}
		bodyReader = bytes.NewReader(b)
	} else {
		bodyReader = bytes.NewReader(nil)
	}

	req := httptest.NewRequest(method, path, bodyReader)
	req.Header.Set("Content-Type", "application/json")
	if authToken != "" {
		req.Header.Set("Authorization", "Bearer "+authToken)
	}

	rr := httptest.NewRecorder()
	handler.ServeHTTP(rr, req)
	return rr
}

func TestHealth(t *testing.T) {
	srv, _, _, _ := newTestServer(t)
	handler := srv.Handler()

	rr := doRequest(t, handler, "GET", "/v1/health", nil, "")
	if rr.Code != http.StatusOK {
		t.Errorf("health status = %d, want 200", rr.Code)
	}
}

func TestPublicKey(t *testing.T) {
	srv, _, _, _ := newTestServer(t)
	handler := srv.Handler()

	rr := doRequest(t, handler, "GET", "/v1/keys/public", nil, "")
	if rr.Code != http.StatusOK {
		t.Errorf("public key status = %d, want 200", rr.Code)
	}

	var jwk map[string]string
	if err := json.Unmarshal(rr.Body.Bytes(), &jwk); err != nil {
		t.Fatalf("unmarshal JWK: %v", err)
	}
	if jwk["kty"] != "OKP" {
		t.Errorf("kty = %q, want OKP", jwk["kty"])
	}
	if jwk["alg"] != "EdDSA" {
		t.Errorf("alg = %q, want EdDSA", jwk["alg"])
	}
}

func TestLoginSuccess(t *testing.T) {
	srv, _, _, _ := newTestServer(t)
	createTestHumanAccount(t, srv, "alice")
	handler := srv.Handler()

	rr := doRequest(t, handler, "POST", "/v1/auth/login", map[string]string{
		"username": "alice",
		"password": "testpass123",
	}, "")

	if rr.Code != http.StatusOK {
		t.Errorf("login status = %d, want 200; body: %s", rr.Code, rr.Body.String())
	}

	var resp loginResponse
	if err := json.Unmarshal(rr.Body.Bytes(), &resp); err != nil {
		t.Fatalf("unmarshal login response: %v", err)
	}
	if resp.Token == "" {
		t.Error("expected non-empty token in login response")
	}
	if resp.ExpiresAt == "" {
		t.Error("expected non-empty expires_at in login response")
	}
}

func TestLoginWrongPassword(t *testing.T) {
	srv, _, _, _ := newTestServer(t)
	createTestHumanAccount(t, srv, "bob")
	handler := srv.Handler()

	rr := doRequest(t, handler, "POST", "/v1/auth/login", map[string]string{
		"username": "bob",
		"password": "wrongpassword",
	}, "")

	if rr.Code != http.StatusUnauthorized {
		t.Errorf("status = %d, want 401", rr.Code)
	}
}

func TestLoginUnknownUser(t *testing.T) {
	srv, _, _, _ := newTestServer(t)
	handler := srv.Handler()

	rr := doRequest(t, handler, "POST", "/v1/auth/login", map[string]string{
		"username": "nobody",
		"password": "password",
	}, "")

	if rr.Code != http.StatusUnauthorized {
		t.Errorf("status = %d, want 401", rr.Code)
	}
}

func TestLoginResponseDoesNotContainCredentials(t *testing.T) {
	srv, _, _, _ := newTestServer(t)
	createTestHumanAccount(t, srv, "charlie")
	handler := srv.Handler()

	rr := doRequest(t, handler, "POST", "/v1/auth/login", map[string]string{
		"username": "charlie",
		"password": "testpass123",
	}, "")

	body := rr.Body.String()
	// Security: password hash must never appear in any API response.
	if strings.Contains(body, "argon2id") || strings.Contains(body, "password_hash") {
		t.Error("login response contains password hash material")
	}
}

func TestTokenValidate(t *testing.T) {
	srv, _, priv, _ := newTestServer(t)
	acct := createTestHumanAccount(t, srv, "dave")
	handler := srv.Handler()

	// Issue and track a token.
	tokenStr, claims, err := token.IssueToken(priv, testIssuer, acct.UUID, nil, time.Hour)
	if err != nil {
		t.Fatalf("IssueToken: %v", err)
	}
	if err := srv.db.TrackToken(claims.JTI, acct.ID, claims.IssuedAt, claims.ExpiresAt); err != nil {
		t.Fatalf("TrackToken: %v", err)
	}

	req := httptest.NewRequest("POST", "/v1/token/validate", nil)
	req.Header.Set("Authorization", "Bearer "+tokenStr)
	rr := httptest.NewRecorder()
	handler.ServeHTTP(rr, req)

	if rr.Code != http.StatusOK {
		t.Fatalf("validate status = %d, want 200", rr.Code)
	}

	var resp validateResponse
	if err := json.Unmarshal(rr.Body.Bytes(), &resp); err != nil {
		t.Fatalf("unmarshal: %v", err)
	}
	if !resp.Valid {
		t.Error("expected valid=true for valid token")
	}
}

func TestLogout(t *testing.T) {
	srv, _, priv, _ := newTestServer(t)
	acct := createTestHumanAccount(t, srv, "eve")
	handler := srv.Handler()

	tokenStr, claims, err := token.IssueToken(priv, testIssuer, acct.UUID, nil, time.Hour)
	if err != nil {
		t.Fatalf("IssueToken: %v", err)
	}
	if err := srv.db.TrackToken(claims.JTI, acct.ID, claims.IssuedAt, claims.ExpiresAt); err != nil {
		t.Fatalf("TrackToken: %v", err)
	}

	// Logout.
	rr := doRequest(t, handler, "POST", "/v1/auth/logout", nil, tokenStr)
	if rr.Code != http.StatusNoContent {
		t.Errorf("logout status = %d, want 204; body: %s", rr.Code, rr.Body.String())
	}

	// Token should now be invalid on validate.
	req := httptest.NewRequest("POST", "/v1/token/validate", nil)
	req.Header.Set("Authorization", "Bearer "+tokenStr)
	rr2 := httptest.NewRecorder()
	handler.ServeHTTP(rr2, req)

	var resp validateResponse
	_ = json.Unmarshal(rr2.Body.Bytes(), &resp)
	if resp.Valid {
		t.Error("expected valid=false after logout")
	}
}

func TestCreateAccountAdmin(t *testing.T) {
	srv, _, priv, _ := newTestServer(t)
	adminToken, _ := issueAdminToken(t, srv, priv, "admin-user")
	handler := srv.Handler()

	rr := doRequest(t, handler, "POST", "/v1/accounts", map[string]string{
		"username":     "new-user",
		"password":     "newpassword123",
		"account_type": "human",
	}, adminToken)

	if rr.Code != http.StatusCreated {
		t.Errorf("create account status = %d, want 201; body: %s", rr.Code, rr.Body.String())
	}

	var resp accountResponse
	if err := json.Unmarshal(rr.Body.Bytes(), &resp); err != nil {
		t.Fatalf("unmarshal: %v", err)
	}
	if resp.Username != "new-user" {
		t.Errorf("Username = %q, want %q", resp.Username, "new-user")
	}
	// Security: password hash must not appear in account response.
	body := rr.Body.String()
	if strings.Contains(body, "password_hash") || strings.Contains(body, "argon2id") {
		t.Error("account creation response contains password hash")
	}
}

func TestCreateAccountRequiresAdmin(t *testing.T) {
	srv, _, priv, _ := newTestServer(t)
	acct := createTestHumanAccount(t, srv, "regular-user")
	tokenStr, claims, err := token.IssueToken(priv, testIssuer, acct.UUID, []string{"reader"}, time.Hour)
	if err != nil {
		t.Fatalf("IssueToken: %v", err)
	}
	if err := srv.db.TrackToken(claims.JTI, acct.ID, claims.IssuedAt, claims.ExpiresAt); err != nil {
		t.Fatalf("TrackToken: %v", err)
	}
	handler := srv.Handler()

	rr := doRequest(t, handler, "POST", "/v1/accounts", map[string]string{
		"username":     "other-user",
		"password":     "password",
		"account_type": "human",
	}, tokenStr)

	if rr.Code != http.StatusForbidden {
		t.Errorf("status = %d, want 403", rr.Code)
	}
}

func TestListAccounts(t *testing.T) {
	srv, _, priv, _ := newTestServer(t)
	adminToken, _ := issueAdminToken(t, srv, priv, "admin2")
	createTestHumanAccount(t, srv, "user1")
	createTestHumanAccount(t, srv, "user2")
	handler := srv.Handler()

	rr := doRequest(t, handler, "GET", "/v1/accounts", nil, adminToken)
	if rr.Code != http.StatusOK {
		t.Errorf("list accounts status = %d, want 200", rr.Code)
	}

	var accounts []accountResponse
	if err := json.Unmarshal(rr.Body.Bytes(), &accounts); err != nil {
		t.Fatalf("unmarshal: %v", err)
	}
	if len(accounts) < 3 { // admin + user1 + user2
		t.Errorf("expected at least 3 accounts, got %d", len(accounts))
	}

	// Security: no credential fields in any response.
	body := rr.Body.String()
	for _, bad := range []string{"password_hash", "argon2id", "totp_secret", "PasswordHash"} {
		if strings.Contains(body, bad) {
			t.Errorf("account list response contains credential field %q", bad)
		}
	}
}

func TestDeleteAccount(t *testing.T) {
	srv, _, priv, _ := newTestServer(t)
	adminToken, _ := issueAdminToken(t, srv, priv, "admin3")
	target := createTestHumanAccount(t, srv, "delete-me")
	handler := srv.Handler()

	rr := doRequest(t, handler, "DELETE", "/v1/accounts/"+target.UUID, nil, adminToken)
	if rr.Code != http.StatusNoContent {
		t.Errorf("delete status = %d, want 204; body: %s", rr.Code, rr.Body.String())
	}
}

func TestSetAndGetRoles(t *testing.T) {
	srv, _, priv, _ := newTestServer(t)
	adminToken, _ := issueAdminToken(t, srv, priv, "admin4")
	target := createTestHumanAccount(t, srv, "role-target")
	handler := srv.Handler()

	// Set roles.
	rr := doRequest(t, handler, "PUT", "/v1/accounts/"+target.UUID+"/roles", map[string][]string{
		"roles": {"reader", "writer"},
	}, adminToken)
	if rr.Code != http.StatusNoContent {
		t.Errorf("set roles status = %d, want 204; body: %s", rr.Code, rr.Body.String())
	}

	// Get roles.
	rr2 := doRequest(t, handler, "GET", "/v1/accounts/"+target.UUID+"/roles", nil, adminToken)
	if rr2.Code != http.StatusOK {
		t.Errorf("get roles status = %d, want 200", rr2.Code)
	}

	var resp rolesResponse
	if err := json.Unmarshal(rr2.Body.Bytes(), &resp); err != nil {
		t.Fatalf("unmarshal: %v", err)
	}
	if len(resp.Roles) != 2 {
		t.Errorf("expected 2 roles, got %d", len(resp.Roles))
	}
}

func TestLoginRateLimited(t *testing.T) {
	srv, _, _, _ := newTestServer(t)
	createTestHumanAccount(t, srv, "ratelimit-user")
	handler := srv.Handler()

	// The login endpoint uses RateLimit(10, 10): burst of 10 requests.
	// Exhaust the burst with 10 requests (valid or invalid — doesn't matter).
	body := map[string]string{
		"username": "ratelimit-user",
		"password": "wrongpassword",
	}
	for i := range 10 {
		rr := doRequest(t, handler, "POST", "/v1/auth/login", body, "")
		if rr.Code == http.StatusTooManyRequests {
			t.Fatalf("request %d was rate-limited prematurely", i+1)
		}
	}

	// The 11th request from the same IP should be rate-limited.
	rr := doRequest(t, handler, "POST", "/v1/auth/login", body, "")
	if rr.Code != http.StatusTooManyRequests {
		t.Errorf("expected 429 after exhausting burst, got %d", rr.Code)
	}

	// Verify the Retry-After header is set.
	if rr.Header().Get("Retry-After") == "" {
		t.Error("expected Retry-After header on 429 response")
	}
}

func TestTokenValidateRateLimited(t *testing.T) {
	srv, _, _, _ := newTestServer(t)
	handler := srv.Handler()

	// The token/validate endpoint shares the same per-IP rate limiter as login.
	// Use a distinct RemoteAddr so we get a fresh bucket.
	body := map[string]string{"token": "not.a.valid.token"}

	for i := range 10 {
		b, _ := json.Marshal(body)
		req := httptest.NewRequest("POST", "/v1/token/validate", bytes.NewReader(b))
		req.Header.Set("Content-Type", "application/json")
		req.RemoteAddr = "10.99.99.1:12345"
		rr := httptest.NewRecorder()
		handler.ServeHTTP(rr, req)
		if rr.Code == http.StatusTooManyRequests {
			t.Fatalf("request %d was rate-limited prematurely", i+1)
		}
	}

	// 11th request should be rate-limited.
	b, _ := json.Marshal(body)
	req := httptest.NewRequest("POST", "/v1/token/validate", bytes.NewReader(b))
	req.Header.Set("Content-Type", "application/json")
	req.RemoteAddr = "10.99.99.1:12345"
	rr := httptest.NewRecorder()
	handler.ServeHTTP(rr, req)
	if rr.Code != http.StatusTooManyRequests {
		t.Errorf("expected 429 after exhausting burst, got %d", rr.Code)
	}
}

func TestHealthNotRateLimited(t *testing.T) {
	srv, _, _, _ := newTestServer(t)
	handler := srv.Handler()

	// Health endpoint should not be rate-limited — send 20 rapid requests.
	for i := range 20 {
		req := httptest.NewRequest("GET", "/v1/health", nil)
		req.RemoteAddr = "10.88.88.1:12345"
		rr := httptest.NewRecorder()
		handler.ServeHTTP(rr, req)
		if rr.Code != http.StatusOK {
			t.Errorf("health request %d: status = %d, want 200", i+1, rr.Code)
		}
	}
}

func TestRenewToken(t *testing.T) {
	srv, _, priv, _ := newTestServer(t)
	acct := createTestHumanAccount(t, srv, "renew-user")
	handler := srv.Handler()

	oldTokenStr, claims, err := token.IssueToken(priv, testIssuer, acct.UUID, nil, time.Hour)
	if err != nil {
		t.Fatalf("IssueToken: %v", err)
	}
	oldJTI := claims.JTI
	if err := srv.db.TrackToken(claims.JTI, acct.ID, claims.IssuedAt, claims.ExpiresAt); err != nil {
		t.Fatalf("TrackToken: %v", err)
	}

	rr := doRequest(t, handler, "POST", "/v1/auth/renew", nil, oldTokenStr)
	if rr.Code != http.StatusOK {
		t.Fatalf("renew status = %d, want 200; body: %s", rr.Code, rr.Body.String())
	}

	var resp loginResponse
	if err := json.Unmarshal(rr.Body.Bytes(), &resp); err != nil {
		t.Fatalf("unmarshal renew response: %v", err)
	}
	if resp.Token == "" || resp.Token == oldTokenStr {
		t.Error("expected new, distinct token after renewal")
	}

	// Old token should be revoked in the database.
	rec, err := srv.db.GetTokenRecord(oldJTI)
	if err != nil {
		t.Fatalf("GetTokenRecord: %v", err)
	}
	if !rec.IsRevoked() {
		t.Error("old token should be revoked after renewal")
	}
}