package api

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

// #105: every validation path on create returns a machine-readable `code`
// alongside the human `error` message, so the new-page JS can map known
// codes to plain-language guidance.

func decodeErr(t *testing.T, rec *httptest.ResponseRecorder) (status int, errMsg, code string) {
	t.Helper()
	var got struct {
		Error string `json:"error"`
		Code  string `json:"code"`
	}
	if err := json.Unmarshal(rec.Body.Bytes(), &got); err != nil {
		t.Fatalf("bad json: %v (%s)", err, rec.Body.String())
	}
	return rec.Code, got.Error, got.Code
}

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

func TestErrorCodeContentEmpty(t *testing.T) {
	h := testServer(t).routes()
	_, _, code := decodeErr(t, postCreate(h, `{"content":"   "}`))
	if code != "content_empty" {
		t.Fatalf("code = %q, want content_empty", code)
	}
}

func TestErrorCodeContentTooLarge(t *testing.T) {
	h := testServer(t).routes()
	big := strings.Repeat("x", 6*1024*1024) // over the 5MB test cap
	_, _, code := decodeErr(t, postCreate(h, `{"content":"`+big+`"}`))
	if code != "content_too_large" {
		t.Fatalf("code = %q, want content_too_large", code)
	}
}

func TestErrorCodeSlugTaken(t *testing.T) {
	h := testServer(t).routes()
	if rec := postCreate(h, `{"content":"a","custom_slug":"taken-slug"}`); rec.Code != 201 {
		t.Fatalf("seed create: %d %s", rec.Code, rec.Body.String())
	}
	_, _, code := decodeErr(t, postCreate(h, `{"content":"b","custom_slug":"taken-slug"}`))
	if code != "slug_taken" {
		t.Fatalf("code = %q, want slug_taken", code)
	}
}

func TestErrorCodeSlugInvalid(t *testing.T) {
	h := testServer(t).routes()
	_, _, code := decodeErr(t, postCreate(h, `{"content":"a","custom_slug":"bad slug!"}`))
	if code != "slug_invalid" {
		t.Fatalf("code = %q, want slug_invalid", code)
	}
}

func TestErrorCodeExpiryInvalid(t *testing.T) {
	h := testServer(t).routes()
	_, _, code := decodeErr(t, postCreate(h, `{"content":"a","expires_in":"2s"}`))
	if code != "expiry_invalid" {
		t.Fatalf("code = %q, want expiry_invalid", code)
	}
}

func TestErrorCodeRateLimited(t *testing.T) {
	h := testServer(t).routes()
	var code string
	for i := 0; i < 20; i++ {
		_, _, code = decodeErr(t, postCreate(h, `{"content":"a"}`))
		if code == "rate_limited" {
			return
		}
	}
	t.Fatalf("never got rate_limited, last code = %q", code)
}

func TestErrorCodeCanValidation(t *testing.T) {
	h := testServer(t).routes()

	post := func(fields map[string]string) *httptest.ResponseRecorder {
		var b strings.Builder
		for k, v := range fields {
			b.WriteString("--B\r\nContent-Disposition: form-data; name=\"" + k + "\"\r\n\r\n" + v + "\r\n")
		}
		b.WriteString("--B--\r\n")
		req := httptest.NewRequest("POST", "/api/pastes/can", strings.NewReader(b.String()))
		req.Header.Set("Content-Type", "multipart/form-data; boundary=B")
		rec := httptest.NewRecorder()
		h.ServeHTTP(rec, req)
		return rec
	}

	// bad visibility
	if _, _, code := decodeErr(t, post(map[string]string{"title": "x", "visibility": "nope"})); code != "invalid_visibility" {
		t.Fatalf("visibility code = %q, want invalid_visibility", code)
	}

	// invalid expiry
	if _, _, code := decodeErr(t, post(map[string]string{"title": "x", "expires_in": "1s"})); code != "expiry_invalid" {
		t.Fatalf("expiry code = %q, want expiry_invalid", code)
	}

	// slug taken on can create
	if rec := postCreate(h, `{"content":"a","custom_slug":"can-slug"}`); rec.Code != 201 {
		t.Fatalf("seed create: %d", rec.Code)
	}
	if _, _, code := decodeErr(t, post(map[string]string{"title": "x", "custom_slug": "can-slug", "json_items": `[{"title":"a","content":"b"}]`})); code != "slug_taken" {
		t.Fatalf("can slug code = %q, want slug_taken", code)
	}
}