package httpapi

import (
	"bytes"
	"encoding/json"
	"html/template"
	"io"
	"log"
	"mime/multipart"
	"net/http"
	"net/http/httptest"
	"path/filepath"
	"runtime"
	"strings"
	"testing"
	"time"

	"scratchbox/internal/config"
	"scratchbox/internal/storage"
)

func TestCreateReadThenExpireScratch(t *testing.T) {
	t.Parallel()

	handler := newTestHandler(t, testServerOptions{
		maxUploadBytes:  1024,
		defaultTTL:      120 * time.Millisecond,
		rateLimitEnable: false,
	})

	createReq := httptest.NewRequest(http.MethodPost, "/api/scratch", bytes.NewBufferString("hello scratch"))
	createReq.Header.Set("Content-Type", "text/plain; charset=utf-8")
	createReq.RemoteAddr = "127.0.0.1:9999"
	createRec := httptest.NewRecorder()
	handler.ServeHTTP(createRec, createReq)
	if createRec.Code != http.StatusCreated {
		t.Fatalf("create status = %d, want %d", createRec.Code, http.StatusCreated)
	}

	var payload map[string]any
	if err := json.Unmarshal(createRec.Body.Bytes(), &payload); err != nil {
		t.Fatalf("decode create payload error = %v", err)
	}
	id, _ := payload["id"].(string)
	if id == "" {
		t.Fatalf("create payload missing id")
	}

	metaReq := httptest.NewRequest(http.MethodGet, "/api/scratch/"+id, nil)
	metaReq.RemoteAddr = "127.0.0.1:9999"
	metaRec := httptest.NewRecorder()
	handler.ServeHTTP(metaRec, metaReq)
	if metaRec.Code != http.StatusOK {
		t.Fatalf("read metadata status = %d, want %d", metaRec.Code, http.StatusOK)
	}

	rawReq := httptest.NewRequest(http.MethodGet, "/raw/"+id, nil)
	rawReq.RemoteAddr = "127.0.0.1:9999"
	rawRec := httptest.NewRecorder()
	handler.ServeHTTP(rawRec, rawReq)
	if rawRec.Code != http.StatusOK {
		t.Fatalf("read raw status = %d, want %d", rawRec.Code, http.StatusOK)
	}
	if got := rawRec.Body.String(); got != "hello scratch" {
		t.Fatalf("raw body = %q, want %q", got, "hello scratch")
	}

	time.Sleep(180 * time.Millisecond)

	expiredReq := httptest.NewRequest(http.MethodGet, "/api/scratch/"+id, nil)
	expiredReq.RemoteAddr = "127.0.0.1:9999"
	expiredRec := httptest.NewRecorder()
	handler.ServeHTTP(expiredRec, expiredReq)
	if expiredRec.Code != http.StatusGone {
		t.Fatalf("expired status = %d, want %d", expiredRec.Code, http.StatusGone)
	}
}

func TestCreateScratchRejectsBodyOverLimit(t *testing.T) {
	t.Parallel()

	handler := newTestHandler(t, testServerOptions{
		maxUploadBytes:  8,
		defaultTTL:      time.Hour,
		rateLimitEnable: false,
	})

	req := httptest.NewRequest(http.MethodPost, "/api/scratch", bytes.NewBufferString("this is too large"))
	req.Header.Set("Content-Type", "text/plain; charset=utf-8")
	req.RemoteAddr = "127.0.0.1:5050"
	rec := httptest.NewRecorder()

	handler.ServeHTTP(rec, req)
	if rec.Code != http.StatusRequestEntityTooLarge {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusRequestEntityTooLarge)
	}
	if !bytes.Contains(rec.Body.Bytes(), []byte("upload exceeds limits.max_upload_size")) {
		t.Fatalf("unexpected body: %q", rec.Body.String())
	}
}

func TestCreateScratchRejectsMultipleMultipartFiles(t *testing.T) {
	t.Parallel()

	handler := newTestHandler(t, testServerOptions{
		maxUploadBytes:  1024,
		defaultTTL:      time.Hour,
		rateLimitEnable: false,
	})

	var body bytes.Buffer
	writer := multipart.NewWriter(&body)
	file1, err := writer.CreateFormFile("file", "first.txt")
	if err != nil {
		t.Fatalf("CreateFormFile first error = %v", err)
	}
	if _, err := file1.Write([]byte("first")); err != nil {
		t.Fatalf("write first file error = %v", err)
	}
	file2, err := writer.CreateFormFile("file", "second.txt")
	if err != nil {
		t.Fatalf("CreateFormFile second error = %v", err)
	}
	if _, err := file2.Write([]byte("second")); err != nil {
		t.Fatalf("write second file error = %v", err)
	}
	if err := writer.Close(); err != nil {
		t.Fatalf("multipart close error = %v", err)
	}

	req := httptest.NewRequest(http.MethodPost, "/api/scratch", &body)
	req.Header.Set("Content-Type", writer.FormDataContentType())
	req.RemoteAddr = "127.0.0.1:5051"
	rec := httptest.NewRecorder()

	handler.ServeHTTP(rec, req)
	if rec.Code != http.StatusBadRequest {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusBadRequest)
	}
	if !bytes.Contains(rec.Body.Bytes(), []byte("only one file is allowed per scratch upload")) {
		t.Fatalf("unexpected body: %q", rec.Body.String())
	}
}

func TestCreateScratchMultipartContentOnly(t *testing.T) {
	t.Parallel()

	handler := newTestHandler(t, testServerOptions{
		maxUploadBytes:  1024,
		defaultTTL:      time.Hour,
		rateLimitEnable: false,
	})

	var body bytes.Buffer
	writer := multipart.NewWriter(&body)
	if err := writer.WriteField("content", "hello from content field"); err != nil {
		t.Fatalf("WriteField() error = %v", err)
	}
	if err := writer.Close(); err != nil {
		t.Fatalf("multipart close error = %v", err)
	}

	req := httptest.NewRequest(http.MethodPost, "/api/scratch", &body)
	req.Header.Set("Content-Type", writer.FormDataContentType())
	req.RemoteAddr = "127.0.0.1:5052"
	rec := httptest.NewRecorder()
	handler.ServeHTTP(rec, req)

	if rec.Code != http.StatusCreated {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusCreated)
	}
}

func TestCreateScratchMultipartRejectsFileAndContent(t *testing.T) {
	t.Parallel()

	handler := newTestHandler(t, testServerOptions{
		maxUploadBytes:  1024,
		defaultTTL:      time.Hour,
		rateLimitEnable: false,
	})

	var body bytes.Buffer
	writer := multipart.NewWriter(&body)
	file, err := writer.CreateFormFile("file", "one.txt")
	if err != nil {
		t.Fatalf("CreateFormFile() error = %v", err)
	}
	if _, err := file.Write([]byte("file content")); err != nil {
		t.Fatalf("write file error = %v", err)
	}
	if err := writer.WriteField("content", "extra content"); err != nil {
		t.Fatalf("WriteField() error = %v", err)
	}
	if err := writer.Close(); err != nil {
		t.Fatalf("multipart close error = %v", err)
	}

	req := httptest.NewRequest(http.MethodPost, "/api/scratch", &body)
	req.Header.Set("Content-Type", writer.FormDataContentType())
	req.RemoteAddr = "127.0.0.1:5053"
	rec := httptest.NewRecorder()
	handler.ServeHTTP(rec, req)

	if rec.Code != http.StatusBadRequest {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusBadRequest)
	}
}

func TestCreateScratchMultipartRequiresFileOrContent(t *testing.T) {
	t.Parallel()

	handler := newTestHandler(t, testServerOptions{
		maxUploadBytes:  1024,
		defaultTTL:      time.Hour,
		rateLimitEnable: false,
	})

	var body bytes.Buffer
	writer := multipart.NewWriter(&body)
	if err := writer.Close(); err != nil {
		t.Fatalf("multipart close error = %v", err)
	}

	req := httptest.NewRequest(http.MethodPost, "/api/scratch", &body)
	req.Header.Set("Content-Type", writer.FormDataContentType())
	req.RemoteAddr = "127.0.0.1:5054"
	rec := httptest.NewRecorder()
	handler.ServeHTTP(rec, req)
	if rec.Code != http.StatusBadRequest {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusBadRequest)
	}
}

func TestGetScratchNotFound(t *testing.T) {
	t.Parallel()

	handler := newTestHandler(t, testServerOptions{
		maxUploadBytes:  1024,
		defaultTTL:      time.Hour,
		rateLimitEnable: false,
	})

	req := httptest.NewRequest(http.MethodGet, "/api/scratch/does-not-exist", nil)
	req.RemoteAddr = "127.0.0.1:5055"
	rec := httptest.NewRecorder()
	handler.ServeHTTP(rec, req)
	if rec.Code != http.StatusNotFound {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusNotFound)
	}
}

func TestRawScratchDefaultsContentType(t *testing.T) {
	t.Parallel()

	handler, store := newTestHandlerAndStore(t, testServerOptions{
		maxUploadBytes:  1024,
		defaultTTL:      time.Hour,
		rateLimitEnable: false,
	})

	meta, err := store.Create(t.Context(), strings.NewReader("no content type"), "", time.Hour)
	if err != nil {
		t.Fatalf("store.Create() error = %v", err)
	}

	req := httptest.NewRequest(http.MethodGet, "/raw/"+meta.ID, nil)
	req.RemoteAddr = "127.0.0.1:5056"
	rec := httptest.NewRecorder()
	handler.ServeHTTP(rec, req)
	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusOK)
	}
	if got := rec.Header().Get("Content-Type"); got != "application/octet-stream" {
		t.Fatalf("Content-Type = %q, want %q", got, "application/octet-stream")
	}
}

func TestViewScratchAndIndexRender(t *testing.T) {
	t.Parallel()

	handler, store := newTemplateHandlerAndStore(t, testServerOptions{
		maxUploadBytes:  10 * 1024 * 1024,
		defaultTTL:      time.Hour,
		rateLimitEnable: false,
	})

	meta, err := store.Create(t.Context(), strings.NewReader("hello view"), "text/plain; charset=utf-8", time.Hour)
	if err != nil {
		t.Fatalf("store.Create() error = %v", err)
	}

	indexReq := httptest.NewRequest(http.MethodGet, "/", nil)
	indexRec := httptest.NewRecorder()
	handler.ServeHTTP(indexRec, indexReq)
	if indexRec.Code != http.StatusOK {
		t.Fatalf("index status = %d, want %d", indexRec.Code, http.StatusOK)
	}

	viewReq := httptest.NewRequest(http.MethodGet, "/s/"+meta.ID, nil)
	viewRec := httptest.NewRecorder()
	handler.ServeHTTP(viewRec, viewReq)
	if viewRec.Code != http.StatusOK {
		t.Fatalf("view status = %d, want %d", viewRec.Code, http.StatusOK)
	}
	if !strings.Contains(viewRec.Body.String(), "hello view") {
		t.Fatalf("expected view body to include scratch content")
	}
}

func TestViewAndRawScratchExpired(t *testing.T) {
	t.Parallel()

	handler, store := newTemplateHandlerAndStore(t, testServerOptions{
		maxUploadBytes:  1024,
		defaultTTL:      time.Hour,
		rateLimitEnable: false,
	})
	meta, err := store.Create(t.Context(), strings.NewReader("expired body"), "text/plain", -time.Second)
	if err != nil {
		t.Fatalf("store.Create() error = %v", err)
	}

	viewReq := httptest.NewRequest(http.MethodGet, "/s/"+meta.ID, nil)
	viewRec := httptest.NewRecorder()
	handler.ServeHTTP(viewRec, viewReq)
	if viewRec.Code != http.StatusGone {
		t.Fatalf("view status = %d, want %d", viewRec.Code, http.StatusGone)
	}

	rawReq := httptest.NewRequest(http.MethodGet, "/raw/"+meta.ID, nil)
	rawRec := httptest.NewRecorder()
	handler.ServeHTTP(rawRec, rawReq)
	if rawRec.Code != http.StatusNotFound {
		t.Fatalf("raw status after lazy delete = %d, want %d", rawRec.Code, http.StatusNotFound)
	}
}

func TestCreateScratchRejectsMalformedMultipart(t *testing.T) {
	t.Parallel()

	handler := newTestHandler(t, testServerOptions{
		maxUploadBytes:  1024,
		defaultTTL:      time.Hour,
		rateLimitEnable: false,
	})

	req := httptest.NewRequest(http.MethodPost, "/api/scratch", strings.NewReader("not-multipart"))
	req.Header.Set("Content-Type", "multipart/form-data; boundary=missing")
	req.RemoteAddr = "127.0.0.1:5057"
	rec := httptest.NewRecorder()
	handler.ServeHTTP(rec, req)
	if rec.Code != http.StatusBadRequest {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusBadRequest)
	}
}

type testServerOptions struct {
	maxUploadBytes  int64
	defaultTTL      time.Duration
	rateLimitEnable bool
}

func newTestHandler(t *testing.T, opts testServerOptions) http.Handler {
	t.Helper()

	handler, _ := newTestHandlerAndStore(t, opts)
	return handler
}

func newTestHandlerAndStore(t *testing.T, opts testServerOptions) (http.Handler, *storage.FilesystemStore) {
	t.Helper()

	dataDir := filepath.Join(t.TempDir(), "data")
	store, err := storage.NewFilesystemStore(dataDir)
	if err != nil {
		t.Fatalf("NewFilesystemStore() error = %v", err)
	}

	cfg := config.Config{
		Server: config.ServerConfig{
			ListenAddr: ":0",
		},
		Limits: config.LimitsConfig{
			MaxUploadSizeBytes: opts.maxUploadBytes,
			DefaultTTLDuration: opts.defaultTTL,
		},
		Storage: config.StorageConfig{
			DataDir: dataDir,
		},
		Security: config.SecurityConfig{
			RateLimit: config.RateLimitConfig{
				Enabled:           opts.rateLimitEnable,
				RequestsPerMinute: 120,
				Burst:             1,
			},
		},
	}

	srv := &Server{
		cfg:       cfg,
		store:     store,
		logger:    log.New(io.Discard, "", 0),
		templates: nil,
	}
	return srv.Routes(), store
}

func newTemplateHandlerAndStore(t *testing.T, opts testServerOptions) (http.Handler, *storage.FilesystemStore) {
	t.Helper()

	handler, store := newTestHandlerAndStore(t, opts)
	_ = handler // keep shared setup path

	_, filePath, _, ok := runtime.Caller(0)
	if !ok {
		t.Fatal("runtime.Caller failed")
	}
	repoRoot := filepath.Clean(filepath.Join(filepath.Dir(filePath), "..", ".."))
	tmpl, err := template.ParseFiles(
		filepath.Join(repoRoot, "web", "templates", "index.html"),
		filepath.Join(repoRoot, "web", "templates", "view.html"),
	)
	if err != nil {
		t.Fatalf("ParseFiles() error = %v", err)
	}

	cfg := config.Config{
		Server: config.ServerConfig{
			ListenAddr: ":0",
		},
		Limits: config.LimitsConfig{
			MaxUploadSizeBytes: opts.maxUploadBytes,
			DefaultTTLDuration: opts.defaultTTL,
		},
		Storage: config.StorageConfig{
			DataDir: filepath.Join(t.TempDir(), "unused"),
		},
		Security: config.SecurityConfig{
			RateLimit: config.RateLimitConfig{
				Enabled:           opts.rateLimitEnable,
				RequestsPerMinute: 120,
				Burst:             1,
			},
		},
	}
	srv := &Server{
		cfg:       cfg,
		store:     store,
		logger:    log.New(io.Discard, "", 0),
		templates: tmpl,
	}
	return srv.Routes(), store
}