package main

import (
	"crypto/tls"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"
)

func TestSessionRoundTrip(t *testing.T) {
	key := sessionKey("token-abc")
	now := time.Now().UnixMilli()
	value := signSession(key, now+60_000)
	if !verifySession(key, value, now) {
		t.Fatal("verifySession = false for a freshly signed cookie, want true")
	}
}

func TestSessionRejects(t *testing.T) {
	key := sessionKey("token-abc")
	now := time.Now().UnixMilli()
	valid := signSession(key, now+60_000)
	payload, sig, _ := strings.Cut(valid, ".")

	cases := []struct {
		name  string
		value string
	}{
		{"empty", ""},
		{"no separator", payload + sig},
		{"unparseable expiry", "notanumber." + sig},
		{"expired", signSession(key, now-1)},
		{"tampered signature", payload + "." + flipLastChar(sig)},
		{"tampered expiry", "99999999999999." + sig},
		{"signed with another key", signSession(sessionKey("other-token"), now+60_000)},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			if verifySession(key, tc.value, now) {
				t.Fatalf("verifySession(%q) = true, want false", tc.value)
			}
		})
	}
}

func flipLastChar(s string) string {
	if s == "" {
		return "x"
	}
	last := s[len(s)-1]
	if last == 'A' {
		return s[:len(s)-1] + "B"
	}
	return s[:len(s)-1] + "A"
}

func TestSessionKeyDependsOnToken(t *testing.T) {
	a := sessionKey("token-a")
	b := sessionKey("token-b")
	if string(a) == string(b) {
		t.Fatal("sessionKey collided for different API tokens")
	}
}

func TestSetSessionCookieAttributes(t *testing.T) {
	cases := []struct {
		name       string
		tls        bool
		forwarded  string
		wantSecure bool
	}{
		{"plain http dev", false, "", false},
		{"direct tls", true, "", true},
		{"behind https proxy", false, "https", true},
		{"behind http proxy", false, "http", false},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			r := httptest.NewRequest(http.MethodPost, "/login", nil)
			if tc.tls {
				r.TLS = &tls.ConnectionState{}
			}
			if tc.forwarded != "" {
				r.Header.Set("X-Forwarded-Proto", tc.forwarded)
			}
			rr := httptest.NewRecorder()
			setSessionCookie(rr, r, sessionKey("token-abc"))

			cookies := rr.Result().Cookies()
			if len(cookies) != 1 {
				t.Fatalf("got %d cookies, want 1", len(cookies))
			}
			c := cookies[0]
			if c.Name != sessionCookieName {
				t.Fatalf("cookie name = %q, want %q", c.Name, sessionCookieName)
			}
			if !c.HttpOnly {
				t.Fatal("cookie HttpOnly = false, want true")
			}
			if c.SameSite != http.SameSiteLaxMode {
				t.Fatalf("cookie SameSite = %v, want Lax", c.SameSite)
			}
			if c.Path != "/" {
				t.Fatalf("cookie Path = %q, want /", c.Path)
			}
			if c.Secure != tc.wantSecure {
				t.Fatalf("cookie Secure = %v, want %v", c.Secure, tc.wantSecure)
			}
			if c.MaxAge != int(sessionTTL/time.Second) {
				t.Fatalf("cookie MaxAge = %d, want %d", c.MaxAge, int(sessionTTL/time.Second))
			}
		})
	}
}

func TestClearSessionCookie(t *testing.T) {
	r := httptest.NewRequest(http.MethodPost, "/logout", nil)
	rr := httptest.NewRecorder()
	clearSessionCookie(rr, r)

	cookies := rr.Result().Cookies()
	if len(cookies) != 1 {
		t.Fatalf("got %d cookies, want 1", len(cookies))
	}
	if cookies[0].MaxAge >= 0 {
		t.Fatalf("cleared cookie MaxAge = %d, want negative", cookies[0].MaxAge)
	}
}