package api

import (
	"bytes"
	"io"
	"mime/multipart"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"

	"github.com/go-chi/chi/v5"

	"git.gophernest.net/azpect/ResumeLens/internal/handlers"
	"git.gophernest.net/azpect/ResumeLens/internal/models"
)

func makeAnalyzeRequestWithJob(t *testing.T, ip, job string) *http.Request {
	t.Helper()
	body := &bytes.Buffer{}
	w := multipart.NewWriter(body)

	part, err := w.CreateFormFile("resume", "resume.pdf")
	if err != nil {
		t.Fatalf("create form file: %v", err)
	}
	if _, err := part.Write([]byte("fake-pdf")); err != nil {
		t.Fatalf("write form file: %v", err)
	}
	if err := w.WriteField("job_description", job); err != nil {
		t.Fatalf("write field: %v", err)
	}
	if err := w.Close(); err != nil {
		t.Fatalf("close writer: %v", err)
	}

	req := httptest.NewRequest(http.MethodPost, "/api/analyze", body)
	req.Header.Set("Content-Type", w.FormDataContentType())
	req.RemoteAddr = ip + ":12345"
	return req
}

func TestSecurity_9_1_1_APIKeyNeverInResponses(t *testing.T) {
	secret := "sk-test-super-secret-123"

	resetRateLimiter()
	restore := handlers.SetAnalyzeResumeForTesting(func(_ io.Reader, _ string) (*models.AnalysisResult, error) {
		return &models.AnalysisResult{OverallScore: 80, Summary: "ok"}, nil
	})
	t.Cleanup(restore)

	r := chi.NewRouter()
	Mount(r)

	success := httptest.NewRecorder()
	r.ServeHTTP(success, makeAnalyzeRequestWithJob(t, "127.0.0.1", "Go role"))
	if strings.Contains(success.Body.String(), secret) {
		t.Fatalf("secret leaked in success response")
	}

	restoreErr := handlers.SetAnalyzeResumeForTesting(func(_ io.Reader, _ string) (*models.AnalysisResult, error) {
		return nil, io.ErrUnexpectedEOF
	})
	t.Cleanup(restoreErr)

	errResp := httptest.NewRecorder()
	r.ServeHTTP(errResp, makeAnalyzeRequestWithJob(t, "127.0.0.2", "Go role"))
	if strings.Contains(errResp.Body.String(), secret) {
		t.Fatalf("secret leaked in error response")
	}
}

func TestSecurity_9_1_2_APIKeyNotInErrorMessages(t *testing.T) {
	secret := "sk-test-never-leak"

	resetRateLimiter()
	restore := handlers.SetAnalyzeResumeForTesting(func(_ io.Reader, _ string) (*models.AnalysisResult, error) {
		return nil, io.ErrUnexpectedEOF
	})
	t.Cleanup(restore)

	r := chi.NewRouter()
	Mount(r)

	rr := httptest.NewRecorder()
	r.ServeHTTP(rr, makeAnalyzeRequestWithJob(t, "127.0.0.1", "Go role"))

	if rr.Code != http.StatusInternalServerError {
		t.Fatalf("expected 500, got %d", rr.Code)
	}
	if strings.Contains(rr.Body.String(), secret) {
		t.Fatalf("secret leaked in error message")
	}
}

func TestSecurity_9_3_1_NoInputSanitization_PassedAsIs(t *testing.T) {
	malicious := "<script>alert('xss')</script> SELECT * FROM users;"

	resetRateLimiter()
	restore := handlers.SetAnalyzeResumeForTesting(func(_ io.Reader, jobDescription string) (*models.AnalysisResult, error) {
		if jobDescription != malicious {
			t.Fatalf("expected exact unsanitized input, got %q", jobDescription)
		}
		return &models.AnalysisResult{OverallScore: 80, Summary: "ok"}, nil
	})
	t.Cleanup(restore)

	r := chi.NewRouter()
	Mount(r)

	rr := httptest.NewRecorder()
	r.ServeHTTP(rr, makeAnalyzeRequestWithJob(t, "127.0.0.1", malicious))
	if rr.Code != http.StatusOK {
		t.Fatalf("expected 200, got %d", rr.Code)
	}
}

func TestSecurity_9_3_2_MaliciousInputHandledAsPlainText(t *testing.T) {
	payload := "'; DROP TABLE resumes; -- $(rm -rf /)"

	resetRateLimiter()
	restore := handlers.SetAnalyzeResumeForTesting(func(_ io.Reader, jobDescription string) (*models.AnalysisResult, error) {
		if jobDescription != payload {
			t.Fatalf("expected exact payload as plain text, got %q", jobDescription)
		}
		return &models.AnalysisResult{OverallScore: 70, Summary: "ok"}, nil
	})
	t.Cleanup(restore)

	r := chi.NewRouter()
	Mount(r)

	rr := httptest.NewRecorder()
	r.ServeHTTP(rr, makeAnalyzeRequestWithJob(t, "127.0.0.1", payload))
	if rr.Code != http.StatusOK {
		t.Fatalf("expected 200, got %d", rr.Code)
	}
}

func TestSecurity_9_4_1_NoAuthenticationRequired(t *testing.T) {
	resetRateLimiter()
	restore := handlers.SetAnalyzeResumeForTesting(func(_ io.Reader, _ string) (*models.AnalysisResult, error) {
		return &models.AnalysisResult{OverallScore: 80, Summary: "ok"}, nil
	})
	t.Cleanup(restore)

	r := chi.NewRouter()
	Mount(r)

	req := makeAnalyzeRequestWithJob(t, "127.0.0.1", "Go role")
	req.Header.Del("Authorization")
	rr := httptest.NewRecorder()
	r.ServeHTTP(rr, req)

	if rr.Code != http.StatusOK {
		t.Fatalf("expected anonymous request to succeed, got %d", rr.Code)
	}
}

func TestSecurity_9_4_2_RateLimitingIsOnlyProtection(t *testing.T) {
	resetRateLimiter()
	restore := handlers.SetAnalyzeResumeForTesting(func(_ io.Reader, _ string) (*models.AnalysisResult, error) {
		return &models.AnalysisResult{OverallScore: 80, Summary: "ok"}, nil
	})
	t.Cleanup(restore)

	r := chi.NewRouter()
	Mount(r)

	for i := 0; i < 10; i++ {
		req := makeAnalyzeRequestWithJob(t, "127.0.0.1", "Go role")
		req.Header.Set("Authorization", "Bearer whatever")
		rr := httptest.NewRecorder()
		r.ServeHTTP(rr, req)
		if rr.Code != http.StatusOK {
			t.Fatalf("request %d expected 200, got %d", i+1, rr.Code)
		}
	}

	blockedReq := makeAnalyzeRequestWithJob(t, "127.0.0.1", "Go role")
	blockedReq.Header.Set("Authorization", "Bearer admin")
	blocked := httptest.NewRecorder()
	r.ServeHTTP(blocked, blockedReq)

	if blocked.Code != http.StatusTooManyRequests {
		t.Fatalf("expected 429 even with auth header, got %d", blocked.Code)
	}
}