package api

// Regression tests for #68 input-validation gaps: negative/oversized content
// lengths (413), limit=0 → default page size, unchecked query params
// (negative offset), and negative burn_after_reads.

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

func createPasteRaw(t *testing.T, h http.Handler, body string) *httptest.ResponseRecorder {
	t.Helper()
	req := httptest.NewRequest("POST", "/api/pastes", strings.NewReader(body))
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	return rec
}

// A request whose decoded content exceeds the admin-tunable cap is rejected
// with 413 and a clear message (content under the body cap, over the
// content cap).
func TestCreatePasteContentOverCap413(t *testing.T) {
	s := testServer(t)
	h := s.routes()

	// content over MaxContentBytes (5MiB) but under body cap (+4KiB): send
	// just over the content cap so the per-field check fires first.
	content := strings.Repeat("a", 5*1024*1024+10)
	rec := createPasteRaw(t, h, fmt.Sprintf(`{"content":"%s"}`, content))
	if rec.Code != http.StatusRequestEntityTooLarge {
		t.Fatalf("got %d want 413: %s", rec.Code, rec.Body.String())
	}
	if !strings.Contains(rec.Body.String(), "content exceeds max") {
		t.Fatalf("unclear error message: %s", rec.Body.String())
	}
}

// A request whose entire body is larger than the server-side body cap is cut
// off by http.MaxBytesReader and answered with 413, not decoded into memory
// (#68: previously a giant body was fully buffered, then rejected only at
// the per-field check — actually the decode happened before any check).
func TestCreatePasteBodyOverCap413(t *testing.T) {
	s := testServer(t)
	// shrink the content cap so the body cap is small too
	ss := s.settings.get()
	ss.MaxContentBytes = 64 * 1024
	if err := s.settings.set(ss); err != nil {
		t.Fatal(err)
	}
	h := s.routes()

	content := strings.Repeat("a", 200*1024) // 200KiB > 64KiB+4KiB body cap
	rec := createPasteRaw(t, h, fmt.Sprintf(`{"content":"%s","title":"x"}`, content))
	if rec.Code != http.StatusRequestEntityTooLarge {
		t.Fatalf("got %d want 413: %s", rec.Code, rec.Body.String())
	}
}

// Negative content lengths cannot be expressed via JSON, but a negative
// expires-style numeric payload must not crash; more importantly the
// burn_after_reads field: negative values are rejected with a clear message.
func TestCreatePasteNegativeBurnAfterReads(t *testing.T) {
	s := testServer(t)
	h := s.routes()

	rec := createPasteRaw(t, h, `{"content":"hi","burn_after_reads":-5}`)
	if rec.Code != http.StatusBadRequest {
		t.Fatalf("got %d want 400: %s", rec.Code, rec.Body.String())
	}
	if !strings.Contains(rec.Body.String(), "burn_after_reads") {
		t.Fatalf("unclear error message: %s", rec.Body.String())
	}

	// 0 and positive values still work (0 = default single read, per #49)
	rec = createPasteRaw(t, h, `{"content":"hi","burn_after_reads":0,"burn_after_read":true}`)
	if rec.Code != http.StatusCreated {
		t.Fatalf("zero burn_after_reads: got %d want 201: %s", rec.Code, rec.Body.String())
	}
}

// limit=0 on list endpoints returns the default page size (existing clamp
// treats <=0 as default; #68 asks this be explicit and tested).
func TestListLimitZeroUsesDefault(t *testing.T) {
	s := testServer(t)
	h := s.routes()

	// seed 3 public pastes
	for i := 0; i < 3; i++ {
		rec := createPasteRaw(t, h, fmt.Sprintf(`{"content":"p%d"}`, i))
		if rec.Code != 201 {
			t.Fatalf("seed: got %d: %s", rec.Code, rec.Body.String())
		}
	}

	for _, q := range []string{"/api/public?limit=0", "/api/public"} {
		req := httptest.NewRequest("GET", q, nil)
		rec := httptest.NewRecorder()
		h.ServeHTTP(rec, req)
		if rec.Code != 200 {
			t.Fatalf("%s: got %d", q, rec.Code)
		}
		var got struct {
			Limit int                   `json:"limit"`
			Total int                   `json:"total"`
			Items []struct{ ID string } `json:"items"`
		}
		json.Unmarshal(rec.Body.Bytes(), &got)
		if got.Limit != 25 || len(got.Items) != 3 {
			t.Fatalf("%s: limit=%d items=%d, want limit 25 and all 3 items", q, got.Limit, len(got.Items))
		}
	}
}

// Huge limit values are clamped to the max page size (already the behavior;
// regression-tested here per #68 "validate unchecked params").
func TestListLimitHugeClamped(t *testing.T) {
	s := testServer(t)
	h := s.routes()

	req := httptest.NewRequest("GET", "/api/public?limit=999999999", nil)
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	var got struct {
		Limit int `json:"limit"`
	}
	json.Unmarshal(rec.Body.Bytes(), &got)
	if got.Limit != 25 {
		t.Fatalf("limit=%d, want clamped to 25", got.Limit)
	}
}

// Negative offset previously passed through unchecked to SQL (harmless in
// SQLite, but invalid); it must be clamped to 0 (#68).
func TestListNegativeOffsetClamped(t *testing.T) {
	s := testServer(t)
	h := s.routes()

	for i := 0; i < 2; i++ {
		rec := createPasteRaw(t, h, fmt.Sprintf(`{"content":"p%d"}`, i))
		if rec.Code != 201 {
			t.Fatalf("seed: got %d", rec.Code)
		}
	}

	req := httptest.NewRequest("GET", "/api/public?offset=-999", nil)
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	if rec.Code != 200 {
		t.Fatalf("got %d", rec.Code)
	}
	var got struct {
		Offset int `json:"offset"`
		Total  int `json:"total"`
	}
	json.Unmarshal(rec.Body.Bytes(), &got)
	if got.Offset != 0 || got.Total != 2 {
		t.Fatalf("offset=%d total=%d, want offset 0 and total 2", got.Offset, got.Total)
	}

	// /api/mine too (needs the viewer cookie)
	req = httptest.NewRequest("GET", "/api/mine?offset=-5", nil)
	req.AddCookie(&http.Cookie{Name: "vwr", Value: "offclamp"})
	rec = httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	var mine struct {
		Offset int `json:"offset"`
	}
	json.Unmarshal(rec.Body.Bytes(), &mine)
	if mine.Offset != 0 {
		t.Fatalf("mine offset=%d, want 0", mine.Offset)
	}
}

// Non-numeric limit/offset fall back to defaults instead of 500s.
func TestListGarbageParams(t *testing.T) {
	s := testServer(t)
	h := s.routes()

	req := httptest.NewRequest("GET", "/api/public?limit=abc&offset=xyz", nil)
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	if rec.Code != 200 {
		t.Fatalf("got %d", rec.Code)
	}
	var got struct {
		Limit  int `json:"limit"`
		Offset int `json:"offset"`
	}
	json.Unmarshal(rec.Body.Bytes(), &got)
	if got.Limit != 25 || got.Offset != 0 {
		t.Fatalf("limit=%d offset=%d, want 25/0", got.Limit, got.Offset)
	}
}