package api

import (
	"context"
	"errors"
	"io"
	"log/slog"
	"net/http"
	"net/http/httptest"
	"testing"
	"time"

	"github.com/iliaivanov/spec-kit-remote/cmd/dev-pod-api/internal/model"
)

// mockKeyValidator implements KeyValidator for testing.
type mockKeyValidator struct {
	users map[string]struct {
		user *model.User
		role string
	}
}

func newMockValidator() *mockKeyValidator {
	return &mockKeyValidator{
		users: make(map[string]struct {
			user *model.User
			role string
		}),
	}
}

func (m *mockKeyValidator) addKey(key string, user *model.User, role string) {
	m.users[key] = struct {
		user *model.User
		role string
	}{user: user, role: role}
}

func (m *mockKeyValidator) ValidateKey(_ context.Context, key string) (*model.User, string, error) {
	entry, ok := m.users[key]
	if !ok {
		return nil, "", errors.New("invalid key")
	}
	return entry.user, entry.role, nil
}

func TestAuthMiddleware_ValidKey(t *testing.T) {
	kv := newMockValidator()
	user := &model.User{ID: "alice", Quota: model.DefaultQuota()}
	kv.addKey("dpk_valid123", user, model.RoleUser)

	var capturedUser *model.User
	var capturedRole string
	handler := AuthMiddleware(kv)(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		capturedUser = UserFromContext(r.Context())
		capturedRole = RoleFromContext(r.Context())
		w.WriteHeader(http.StatusOK)
	}))

	req := httptest.NewRequest(http.MethodGet, "/", nil)
	req.Header.Set("Authorization", "Bearer dpk_valid123")
	rr := httptest.NewRecorder()
	handler.ServeHTTP(rr, req)

	if rr.Code != http.StatusOK {
		t.Fatalf("expected 200, got %d", rr.Code)
	}
	if capturedUser == nil || capturedUser.ID != "alice" {
		t.Fatalf("expected user alice, got %v", capturedUser)
	}
	if capturedRole != model.RoleUser {
		t.Fatalf("expected role user, got %s", capturedRole)
	}
}

func TestAuthMiddleware_AdminKey(t *testing.T) {
	kv := newMockValidator()
	admin := &model.User{ID: "admin-user", Quota: model.DefaultQuota()}
	kv.addKey("dpk_admin456", admin, model.RoleAdmin)

	var capturedRole string
	handler := AuthMiddleware(kv)(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		capturedRole = RoleFromContext(r.Context())
		w.WriteHeader(http.StatusOK)
	}))

	req := httptest.NewRequest(http.MethodGet, "/", nil)
	req.Header.Set("Authorization", "Bearer dpk_admin456")
	rr := httptest.NewRecorder()
	handler.ServeHTTP(rr, req)

	if rr.Code != http.StatusOK {
		t.Fatalf("expected 200, got %d", rr.Code)
	}
	if capturedRole != model.RoleAdmin {
		t.Fatalf("expected role admin, got %s", capturedRole)
	}
}

func TestAuthMiddleware_MissingHeader(t *testing.T) {
	kv := newMockValidator()
	handler := AuthMiddleware(kv)(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		t.Fatal("handler should not be called")
	}))

	req := httptest.NewRequest(http.MethodGet, "/", nil)
	rr := httptest.NewRecorder()
	handler.ServeHTTP(rr, req)

	if rr.Code != http.StatusUnauthorized {
		t.Fatalf("expected 401, got %d", rr.Code)
	}
}

func TestAuthMiddleware_InvalidFormat(t *testing.T) {
	kv := newMockValidator()
	handler := AuthMiddleware(kv)(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		t.Fatal("handler should not be called")
	}))

	tests := []struct {
		name  string
		value string
	}{
		{"no bearer prefix", "dpk_abc123"},
		{"basic auth", "Basic dXNlcjpwYXNz"},
		{"empty bearer", "Bearer "},
		{"bearer lowercase", "bearer dpk_abc123"},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			req := httptest.NewRequest(http.MethodGet, "/", nil)
			req.Header.Set("Authorization", tt.value)
			rr := httptest.NewRecorder()
			handler.ServeHTTP(rr, req)

			if rr.Code != http.StatusUnauthorized {
				t.Fatalf("expected 401, got %d", rr.Code)
			}
		})
	}
}

func TestAuthMiddleware_InvalidKey(t *testing.T) {
	kv := newMockValidator()
	handler := AuthMiddleware(kv)(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		t.Fatal("handler should not be called")
	}))

	req := httptest.NewRequest(http.MethodGet, "/", nil)
	req.Header.Set("Authorization", "Bearer dpk_doesnotexist")
	rr := httptest.NewRecorder()
	handler.ServeHTTP(rr, req)

	if rr.Code != http.StatusUnauthorized {
		t.Fatalf("expected 401, got %d", rr.Code)
	}
}

func TestRateLimiter_UnderLimit(t *testing.T) {
	rl := NewRateLimiter(1.0, 60)
	for i := range 60 {
		if !rl.Allow("user1") {
			t.Fatalf("request %d should be allowed (under burst limit)", i+1)
		}
	}
}

func TestRateLimiter_OverLimit(t *testing.T) {
	rl := NewRateLimiter(1.0, 5)

	// Exhaust the burst
	for range 5 {
		rl.Allow("user1")
	}

	// Next request should be rejected
	if rl.Allow("user1") {
		t.Fatal("request should be rejected after burst exhausted")
	}
}

func TestRateLimiter_DifferentKeys(t *testing.T) {
	rl := NewRateLimiter(1.0, 2)

	// Exhaust user1's burst
	rl.Allow("user1")
	rl.Allow("user1")
	if rl.Allow("user1") {
		t.Fatal("user1 should be rate limited")
	}

	// user2 should still be allowed
	if !rl.Allow("user2") {
		t.Fatal("user2 should not be affected by user1's rate limit")
	}
}

func TestRateLimiter_Refill(t *testing.T) {
	rl := NewRateLimiter(1.0, 2)

	// Use a controllable time function
	now := time.Now()
	rl.nowFunc = func() time.Time { return now }

	// Exhaust burst
	rl.Allow("user1")
	rl.Allow("user1")
	if rl.Allow("user1") {
		t.Fatal("should be rate limited")
	}

	// Advance time by 1 second (1 token refill at 1/s)
	now = now.Add(1 * time.Second)
	if !rl.Allow("user1") {
		t.Fatal("should be allowed after token refill")
	}
}

func TestRateLimiter_Middleware(t *testing.T) {
	rl := NewRateLimiter(1.0, 2)

	handlerCalls := 0
	handler := rl.Middleware(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		handlerCalls++
		w.WriteHeader(http.StatusOK)
	}))

	// Set up authenticated context
	user := &model.User{ID: "alice"}
	for i := range 3 {
		req := httptest.NewRequest(http.MethodGet, "/", nil)
		ctx := context.WithValue(req.Context(), ctxKeyUser, user)
		req = req.WithContext(ctx)
		rr := httptest.NewRecorder()
		handler.ServeHTTP(rr, req)

		if i < 2 {
			if rr.Code != http.StatusOK {
				t.Fatalf("request %d: expected 200, got %d", i+1, rr.Code)
			}
		} else {
			if rr.Code != http.StatusTooManyRequests {
				t.Fatalf("request %d: expected 429, got %d", i+1, rr.Code)
			}
		}
	}

	if handlerCalls != 2 {
		t.Fatalf("expected 2 handler calls, got %d", handlerCalls)
	}
}

func TestRequestLogger(t *testing.T) {
	logger := slog.New(slog.NewTextHandler(io.Discard, nil))
	handler := RequestLogger(logger)(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusCreated)
	}))

	req := httptest.NewRequest(http.MethodPost, "/test", nil)
	rr := httptest.NewRecorder()
	handler.ServeHTTP(rr, req)

	if rr.Code != http.StatusCreated {
		t.Fatalf("expected 201, got %d", rr.Code)
	}
}

func TestStatusWriter_DefaultStatus(t *testing.T) {
	rr := httptest.NewRecorder()
	sw := &statusWriter{ResponseWriter: rr, status: http.StatusOK}
	sw.Write([]byte("hello"))
	if sw.status != http.StatusOK {
		t.Fatalf("expected default 200, got %d", sw.status)
	}
}

func TestStatusWriter_ExplicitStatus(t *testing.T) {
	rr := httptest.NewRecorder()
	sw := &statusWriter{ResponseWriter: rr, status: http.StatusOK}
	sw.WriteHeader(http.StatusNotFound)
	if sw.status != http.StatusNotFound {
		t.Fatalf("expected 404, got %d", sw.status)
	}

	// Second WriteHeader should be ignored
	sw.WriteHeader(http.StatusOK)
	if sw.status != http.StatusNotFound {
		t.Fatalf("expected 404 after double write, got %d", sw.status)
	}
}