package main

import (
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"
)

type anyHandler interface {
	ServeHTTP(http.ResponseWriter, *http.Request)
}

// createBurnReads creates a burn-after-N-reads paste and returns its id.
func createBurnReads(t *testing.T, h anyHandler, reads int) string {
	t.Helper()
	body, _ := json.Marshal(map[string]any{"content": "limited", "burn_after_read": true, "burn_after_reads": reads})
	req := httptest.NewRequest("POST", "/api/pastes", strings.NewReader(string(body)))
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	if rec.Code != 201 {
		t.Fatalf("create burn_after_reads=%d: %d %s", reads, rec.Code, rec.Body.String())
	}
	var created struct {
		ID string `json:"id"`
	}
	json.Unmarshal(rec.Body.Bytes(), &created)
	if created.ID == "" {
		t.Fatal("no id in create response")
	}
	return created.ID
}

func getWithCookie(t *testing.T, h anyHandler, id, viewer string) *httptest.ResponseRecorder {
	t.Helper()
	req := httptest.NewRequest("GET", "/api/pastes/"+id, nil)
	if viewer != "" {
		req.AddCookie(&http.Cookie{Name: "vwr", Value: viewer})
	}
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	return rec
}

func TestBurnAfterNReadsDistinctViewers(t *testing.T) {
	s := testServer(t)
	h := s.routes()
	id := createBurnReads(t, h, 2)

	// viewer A: ok (read 1)
	if rec := getWithCookie(t, h, id, "aaa"); rec.Code != 200 {
		t.Fatalf("read 1 (viewer A): %d %s", rec.Code, rec.Body.String())
	}
	// viewer B: ok (read 2)
	if rec := getWithCookie(t, h, id, "bbb"); rec.Code != 200 {
		t.Fatalf("read 2 (viewer B): %d %s", rec.Code, rec.Body.String())
	}
	// viewer C: burned -> 404
	if rec := getWithCookie(t, h, id, "ccc"); rec.Code != 404 {
		t.Fatalf("read 3 expected 404, got %d", rec.Code)
	}
}

func TestBurnReadsSameViewerWithinWindowNoDecrement(t *testing.T) {
	s := testServer(t)
	h := s.routes()
	id := createBurnReads(t, h, 2)

	// same viewer reads twice within the window: second is deduped
	if rec := getWithCookie(t, h, id, "aaa"); rec.Code != 200 {
		t.Fatalf("read 1: %d", rec.Code)
	}
	if rec := getWithCookie(t, h, id, "aaa"); rec.Code != 200 {
		t.Fatalf("deduped re-read expected 200, got %d", rec.Code)
	}
	// another viewer still gets read 2 (budget not consumed by re-reads)
	if rec := getWithCookie(t, h, id, "bbb"); rec.Code != 200 {
		t.Fatalf("read 2: %d", rec.Code)
	}
}

func TestBurnReadsWindowExpiryRecounts(t *testing.T) {
	s := testServer(t)
	h := s.routes()
	id := createBurnReads(t, h, 2)

	base := time.Now()
	timeNow = func() time.Time { return base }
	t.Cleanup(func() { timeNow = time.Now })

	if rec := getWithCookie(t, h, id, "aaa"); rec.Code != 200 {
		t.Fatalf("read 1: %d", rec.Code)
	}
	// 10 minutes later: still within window, deduped
	timeNow = func() time.Time { return base.Add(10 * time.Minute) }
	if rec := getWithCookie(t, h, id, "aaa"); rec.Code != 200 {
		t.Fatalf("re-read within window: %d", rec.Code)
	}
	// 20 minutes after first read: window expired, counts as read 2
	timeNow = func() time.Time { return base.Add(20 * time.Minute) }
	if rec := getWithCookie(t, h, id, "aaa"); rec.Code != 200 {
		t.Fatalf("re-read after window expected 200, got %d", rec.Code)
	}
	// budget exhausted -> 404 even for the same viewer
	if rec := getWithCookie(t, h, id, "aaa"); rec.Code != 404 {
		t.Fatalf("after budget expected 404, got %d", rec.Code)
	}
}

func TestBurnReadsDefaultOne(t *testing.T) {
	s := testServer(t)
	h := s.routes()
	// burn_after_read without burn_after_reads defaults to 1 read
	req := httptest.NewRequest("POST", "/api/pastes", strings.NewReader(`{"content":"one","burn_after_read":true}`))
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	var created struct {
		ID string `json:"id"`
	}
	json.Unmarshal(rec.Body.Bytes(), &created)

	if rec := getWithCookie(t, h, created.ID, "aaa"); rec.Code != 200 {
		t.Fatalf("read 1: %d", rec.Code)
	}
	if rec := getWithCookie(t, h, created.ID, "bbb"); rec.Code != 404 {
		t.Fatalf("read 2 expected 404, got %d", rec.Code)
	}
}

func TestBurnReadsPageViewCounts(t *testing.T) {
	if webUIInstance == nil {
		ui, err := NewWebUI()
		if err != nil {
			t.Fatal(err)
		}
		webUIInstance = ui
	}
	s := testServer(t)
	h := s.routes()
	id := createBurnReads(t, h, 2)

	// HTML page view counts as a read too (documented decision)
	req := httptest.NewRequest("GET", "/"+id, nil)
	req.AddCookie(&http.Cookie{Name: "vwr", Value: "aaa"})
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	if rec.Code != 200 {
		t.Fatalf("page view 1: %d", rec.Code)
	}
	// re-view within window: deduped
	req = httptest.NewRequest("GET", "/"+id, nil)
	req.AddCookie(&http.Cookie{Name: "vwr", Value: "aaa"})
	rec = httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	if rec.Code != 200 {
		t.Fatalf("page re-view: %d", rec.Code)
	}
	// distinct viewer: read 2, page renders with reads remaining
	req = httptest.NewRequest("GET", "/"+id, nil)
	req.AddCookie(&http.Cookie{Name: "vwr", Value: "bbb"})
	rec = httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	if rec.Code != 200 {
		t.Fatalf("page view 2: %d", rec.Code)
	}
	if !strings.Contains(rec.Body.String(), "Reads left") {
		t.Fatal("stats pill missing 'Reads left'")
	}
	// third viewer: burned
	req = httptest.NewRequest("GET", "/"+id, nil)
	req.AddCookie(&http.Cookie{Name: "vwr", Value: "ccc"})
	rec = httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	if rec.Code != 404 {
		t.Fatalf("page view 3 expected 404, got %d", rec.Code)
	}
}