package wristband

import (
	"net/http"
	"net/http/httptest"
	"net/url"
	"strings"
	"testing"
	"time"
)

// insertAuthorizeTestClient inserts an already-usable ClientRecord directly
// into backend (bypassing CreateWithCap's cap/sweep policy, which this
// plan's tests do not exercise) and returns it.
func insertAuthorizeTestClient(backend *memoryBackend, clientID string, redirectURIs []string, ceiling []string) *ClientRecord {
	backend.mu.Lock()
	defer backend.mu.Unlock()
	backend.nextID++
	rec := &ClientRecord{
		ID:                      backend.nextID,
		ClientID:                clientID,
		ClientName:              "Test Client",
		RedirectURIs:            redirectURIs,
		GrantTypes:              []string{"authorization_code", "refresh_token"},
		TokenEndpointAuthMethod: "client_secret_post",
		ScopeCeiling:            ceiling,
		CreatedAt:               time.Now(),
	}
	backend.clients = append(backend.clients, rec)
	return rec
}

// s256Pair returns a random PKCE verifier and its S256 challenge, matching
// the byte transform every Phase 8 PHP/Go PKCE fixture shares.
func s256Pair(t *testing.T) (verifier, challenge string) {
	t.Helper()
	v, err := randomBase64URL(32)
	if err != nil {
		t.Fatal(err)
	}
	return v, s256Challenge(v)
}

// authorizeQuery builds a GET /oauth/mcp/authorize request from an ordered
// param map (net/url.Values handles encoding fine for *requests*: only
// response Location construction is bound by the RFC3986 ordered-pair
// requirement).
func authorizeRequest(params map[string]string) *http.Request {
	q := url.Values{}
	for k, v := range params {
		q.Set(k, v)
	}
	return httptest.NewRequest(http.MethodGet, "/oauth/mcp/authorize?"+q.Encode(), nil)
}

// queryOf parses the query component of a redirect Location header into a
// flat map (every Phase 8 authorize fixture uses at most one value per key).
func queryOf(t *testing.T, location string) map[string]string {
	t.Helper()
	u, err := url.Parse(location)
	if err != nil {
		t.Fatalf("parse Location %q: %v", location, err)
	}
	out := map[string]string{}
	for k, v := range u.Query() {
		if len(v) > 0 {
			out[k] = v[0]
		}
	}
	return out
}

// TestPhase8RedAuthorize is the Phase 8 Wave 3 RED anchor (08-03-PLAN.md
// Task 1, D-02/D-04/D-05). It drives one valid S256 authorize request
// through the real (in-memory-backed) Server.Authorize and asserts the
// exact success contract: 302 to <issuer>/connect?request=<opaque> with no
// state/code leaked onto our own redirect and Cache-Control: no-store. It
// fails with the PHASE8_RED:authorize sentinel while Authorize is the 501
// stub; scripts/check-phase8-red.sh verifies this failure is fail-closed.
func TestPhase8RedAuthorize(t *testing.T) {
	backend := newMemoryBackend()
	srv := newTestServer(backend)
	insertAuthorizeTestClient(backend, "cli-red", []string{"https://chatgpt.com/connector/oauth/cb"}, nil)
	_, challenge := s256Pair(t)

	req := authorizeRequest(map[string]string{
		"client_id":             "cli-red",
		"redirect_uri":          "https://chatgpt.com/connector/oauth/cb",
		"response_type":         "code",
		"code_challenge":        challenge,
		"code_challenge_method": "S256",
		"scope":                 "read write",
		"state":                 "must-not-appear-on-our-url",
		"resource":              "https://mcp.plytarium.com/mcp",
	})
	rec := httptest.NewRecorder()
	srv.Authorize(rec, req)

	if rec.Code != http.StatusFound {
		t.Fatalf("PHASE8_RED:authorize: status = %d, want %d (body=%s)", rec.Code, http.StatusFound, rec.Body.String())
	}
	loc := rec.Header().Get("Location")
	if !strings.HasPrefix(loc, "https://plytarium.com/connect?") {
		t.Fatalf("PHASE8_RED:authorize: Location = %q, want prefix \"https://plytarium.com/connect?\"", loc)
	}
	q := queryOf(t, loc)
	if q["request"] == "" {
		t.Fatalf("PHASE8_RED:authorize: Location %q missing non-empty request param", loc)
	}
	if _, has := q["state"]; has {
		t.Fatalf("PHASE8_RED:authorize: Location %q leaks state onto our own redirect", loc)
	}
	if _, has := q["code"]; has {
		t.Fatalf("PHASE8_RED:authorize: Location %q leaks a code onto our own redirect", loc)
	}
	if cc := rec.Header().Get("Cache-Control"); cc != "no-store" {
		t.Fatalf("PHASE8_RED:authorize: Cache-Control = %q, want \"no-store\"", cc)
	}
}