package main

import (
	"log/slog"
	"net/http"
	"net/http/httptest"
	"os"
	"strings"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	"github.com/mathiasbq/hyperguild/ingestion/internal/api"
	"github.com/mathiasbq/hyperguild/ingestion/internal/metrics"
	"github.com/mathiasbq/hyperguild/ingestion/internal/pipeline"
)

const routesTok = "routes-test-token"

func okHandler(body string) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) { _, _ = w.Write([]byte(body)) })
}

// testMux builds the router exactly as main does: buildMux with the full
// public set main registers (stub handlers), a stub MCP server, and real
// bearer config. hyperguild#149: the REST API is authenticated as a whole;
// the PR #152 review showed a test of a COPY of the router let main.go
// regress unseen.
func testMux(t *testing.T) http.Handler {
	t.Helper()
	mux, _ := testMuxAndRegistry(t)
	return mux
}

func testMuxAndRegistry(t *testing.T) (http.Handler, *metrics.Registry) {
	t.Helper()
	public := map[string]http.Handler{}
	for p := range publicRoutes {
		public[p] = okHandler("public " + p)
	}
	reg := metrics.New()
	mux, err := buildMux(restAuth{token: routesTok, realm: "brain"}, testHandler(t), okHandler("mcp"), reg, public)
	require.NoError(t, err)
	return mux, reg
}

func testHandler(t *testing.T) *api.Handler {
	t.Helper()
	return api.NewHandler(t.TempDir(), slog.New(slog.NewTextHandler(os.Stderr, nil)), pipeline.Config{})
}

func do(t *testing.T, h http.Handler, method, path, authz string) (int, string) {
	t.Helper()
	req := httptest.NewRequest(method, path, strings.NewReader(`{"query":"x"}`))
	if authz != "" {
		req.Header.Set("Authorization", authz)
	}
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	return rec.Code, rec.Body.String()
}

func TestBuildMuxRefusesRESTRoutesWithoutAValidToken(t *testing.T) {
	r := testMux(t)
	for _, rt := range []struct{ method, path string }{
		{"POST", "/query"}, {"POST", "/write"}, {"POST", "/index"}, {"POST", "/ingest"},
		{"POST", "/ingest-path"}, {"POST", "/ingest-raw"}, {"POST", "/backfill-refs"},
		{"GET", "/pending"}, {"POST", "/promote"}, {"POST", "/backfill-embeddings"}, {"GET", "/pass-rate"},
	} {
		code, _ := do(t, r, rt.method, rt.path, "")
		assert.Equal(t, http.StatusUnauthorized, code, "%s %s without a token", rt.method, rt.path)
		code, _ = do(t, r, rt.method, rt.path, "Bearer wrong")
		assert.Equal(t, http.StatusUnauthorized, code, "%s %s with a wrong token", rt.method, rt.path)
	}
}

func TestBuildMuxServesRESTRoutesToAValidToken(t *testing.T) {
	r := testMux(t)
	code, _ := do(t, r, "GET", "/pending", "Bearer "+routesTok)
	assert.Equal(t, http.StatusOK, code)
}

func TestBuildMuxAuthenticatesAnUnregisteredPath(t *testing.T) {
	code, _ := do(t, testMux(t), "POST", "/some-future-route", "")
	assert.Equal(t, http.StatusUnauthorized, code)
}

// buildMux registers public handlers as given, without adding auth: each
// public route owns its own (bearer on /mcp, HMAC on the webhook, client
// secret on /oauth/token) or is meant to be open (/metrics, OAuth metadata).
func TestBuildMuxDoesNotWrapPublicRoutes(t *testing.T) {
	r := testMux(t)
	for p := range publicRoutes {
		method, path, ok := strings.Cut(p, " ")
		if !ok {
			method, path = "GET", p
		}
		code, body := do(t, r, method, path, "")
		assert.Equal(t, http.StatusOK, code, p)
		assert.Equal(t, "public "+p, body, p)
	}
}

// The allowlist is the control: a REST pattern registered as public would win
// over the authenticated catch-all (more specific pattern), so it is refused.
func TestBuildMuxRefusesAPublicPatternOffTheAllowlist(t *testing.T) {
	h := api.NewHandler(t.TempDir(), slog.New(slog.NewTextHandler(os.Stderr, nil)), pipeline.Config{})
	// "/mcp" and "GET /metrics" are built by buildMux itself (hyperguild#154):
	// passing either as public would register them unauthenticated or twice.
	for _, p := range []string{"POST /query", "GET /pending", "/", "POST /metrics", "/mcp", "GET /metrics"} {
		_, err := buildMux(restAuth{token: routesTok, realm: "brain"}, h, okHandler("mcp"), metrics.New(),
			map[string]http.Handler{p: okHandler("x")})
		assert.Error(t, err, "public pattern %q must be refused", p)
	}
}

func TestBuildMuxRefusesAnEmptyToken(t *testing.T) {
	h := api.NewHandler(t.TempDir(), slog.New(slog.NewTextHandler(os.Stderr, nil)), pipeline.Config{})
	_, err := buildMux(restAuth{token: "", realm: "brain"}, h, okHandler("mcp"), metrics.New(), nil)
	assert.Error(t, err)
}

// hyperguild#154: /mcp's bearer was built in main.go, untested; the buildMux
// tests used stubs. buildMux now wraps the MCP handler itself, with the same
// credential as the REST API.
func TestBuildMuxRefusesMCPWithoutAValidToken(t *testing.T) {
	r := testMux(t)
	for _, authz := range []string{"", "Bearer wrong"} {
		code, body := do(t, r, "POST", "/mcp", authz)
		assert.Equal(t, http.StatusUnauthorized, code, "authz %q", authz)
		assert.NotEqual(t, "mcp", body)
	}
	code, body := do(t, r, "POST", "/mcp", "Bearer "+routesTok)
	assert.Equal(t, http.StatusOK, code)
	assert.Equal(t, "mcp", body)
}

func TestBuildMuxRefusesANilMCPHandlerOrRegistry(t *testing.T) {
	auth := restAuth{token: routesTok, realm: "brain"}
	_, err := buildMux(auth, testHandler(t), nil, metrics.New(), nil)
	assert.Error(t, err)
	_, err = buildMux(auth, testHandler(t), okHandler("mcp"), nil, nil)
	assert.Error(t, err)
}

// hyperguild#154: main wrapped buildMux's result in the metrics middleware
// before ListenAndServe, untested. buildMux now returns the handler main
// serves as-is, metrics included: a request through it is observed and
// exposed on its own GET /metrics.
func TestBuildMuxObservesRequestsAndServesMetrics(t *testing.T) {
	r := testMux(t)
	code, _ := do(t, r, "GET", "/pending", "Bearer "+routesTok)
	require.Equal(t, http.StatusOK, code)
	code, body := do(t, r, "GET", "/metrics", "")
	require.Equal(t, http.StatusOK, code)
	assert.Contains(t, body, `path="GET /pending"`)
}