package server

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

// fakeAuthMiddleware simulates auth.Config.Middleware for
// newRouteAwareHandler tests, without standing up a real session manager:
// a request carrying X-Fake-Authed is treated as authenticated and passed
// through; everything else is redirected to /login (302), or answered 401
// with HX-Redirect for an HTMX request, matching the shape of the real
// auth middleware's HTMX branch (auth.Config.Middleware) closely enough to
// exercise newRouteAwareHandler's dispatch decision.
func fakeAuthMiddleware(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path == "/login" || r.Header.Get("X-Fake-Authed") == "true" {
			next.ServeHTTP(w, r)
			return
		}
		if r.Header.Get("HX-Request") == "true" {
			w.Header().Set("HX-Redirect", "/login")
			w.WriteHeader(http.StatusUnauthorized)
			return
		}
		http.Redirect(w, r, "/login", http.StatusFound)
	})
}

func newTestRouteAwareMux() *http.ServeMux {
	mux := http.NewServeMux()
	mux.HandleFunc("/login", func(w http.ResponseWriter, r *http.Request) {
		w.Write([]byte("login page"))
	})
	mux.HandleFunc("GET /protected", func(w http.ResponseWriter, r *http.Request) {
		w.Write([]byte("protected content"))
	})
	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		// Mirrors Start()'s own "/" handler: only the literal root is real,
		// anything else that reaches this point is a bug in the pre-check.
		if r.URL.Path != "/" {
			http.Error(w, "unexpected: routeAware should have intercepted this", http.StatusNotFound)
			return
		}
		w.Write([]byte("dashboard"))
	})
	return mux
}

// TestNewRouteAwareHandler covers design.md Decision 4 / the error-pages
// delta's route-existence-before-auth-redirect requirement: an anonymous
// request for a path no route matches gets the styled 404 without ever
// reaching the auth middleware (no session required, no IdP redirect); a
// path that DOES match a real route keeps the ordinary auth-wrapped
// dispatch, including the login redirect when the session is absent, and
// authenticated behavior on both matched and unmatched paths is unchanged.
func TestNewRouteAwareHandler(t *testing.T) {
	tests := []struct {
		name          string
		path          string
		authed        bool
		hxRequest     bool
		wantStatus    int
		wantStyled404 bool // body contains the styled error.html page
		wantRedirect  string
		wantBody      string
	}{
		{
			name:          "anonymous unknown route gets styled 404, not a login redirect",
			path:          "/no-such-page",
			authed:        false,
			wantStatus:    http.StatusNotFound,
			wantStyled404: true,
		},
		{
			name:         "anonymous real protected route still redirects to login",
			path:         "/protected",
			authed:       false,
			wantStatus:   http.StatusFound,
			wantRedirect: "/login",
		},
		{
			name:          "authenticated unknown route still gets styled 404 (existing behavior stays)",
			path:          "/no-such-page",
			authed:        true,
			wantStatus:    http.StatusNotFound,
			wantStyled404: true,
		},
		{
			name:       "authenticated real protected route reaches the real handler",
			path:       "/protected",
			authed:     true,
			wantStatus: http.StatusOK,
			wantBody:   "protected content",
		},
		{
			name:          "HTMX request to an unknown route keeps the HX-aware plain-text 404",
			path:          "/no-such-page",
			authed:        false,
			hxRequest:     true,
			wantStatus:    http.StatusNotFound,
			wantStyled404: false,
			wantBody:      "The page you requested does not exist.",
		},
		{
			name:       "HTMX request to a real protected route keeps the 10e HX-aware unauthorized response",
			path:       "/protected",
			authed:     false,
			hxRequest:  true,
			wantStatus: http.StatusUnauthorized,
		},
	}

	mux := newTestRouteAwareMux()
	tmpl := errorPageTemplates(t)
	handler := newRouteAwareHandler(mux, fakeAuthMiddleware, tmpl)

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			req := httptest.NewRequest("GET", tt.path, nil)
			if tt.authed {
				req.Header.Set("X-Fake-Authed", "true")
			}
			if tt.hxRequest {
				req.Header.Set("HX-Request", "true")
			}
			rec := httptest.NewRecorder()
			handler.ServeHTTP(rec, req)

			if rec.Code != tt.wantStatus {
				t.Fatalf("status = %d, want %d (body: %s)", rec.Code, tt.wantStatus, rec.Body.String())
			}
			if tt.wantRedirect != "" {
				if loc := rec.Header().Get("Location"); loc != tt.wantRedirect {
					t.Errorf("Location = %q, want %q", loc, tt.wantRedirect)
				}
			}
			body := rec.Body.String()
			if tt.wantStyled404 {
				for _, want := range []string{"404", "Not Found", "navbar-brand"} {
					if !strings.Contains(body, want) {
						t.Errorf("styled 404 body missing %q: %s", want, body)
					}
				}
			}
			if tt.wantBody != "" && strings.TrimSpace(body) != tt.wantBody {
				t.Errorf("body = %q, want %q", body, tt.wantBody)
			}
		})
	}
}