package server

import (
	"mime"
	"strings"
	"testing"
)

// Content-Disposition is the header that keeps an uploaded file from being
// rendered, so it has to survive whatever a filename throws at it.
func TestContentDisposition(t *testing.T) {
	cases := []struct {
		name      string
		wantASCII string
		wantExt   bool // expect an RFC 5987 filename* parameter too
	}{
		{"MyGame.zip", "MyGame.zip", false},
		{"notes (draft).txt", "notes (draft).txt", false},
		{`quo"te.txt`, "quo_te.txt", true},
		{`back\slash.txt`, "back_slash.txt", true},
		{"naïve.txt", "na_ve.txt", true},
		{"日本語.bin", "___.bin", true},
		{"🙂.png", "_.png", true},
	}
	for _, c := range cases {
		got := contentDisposition(c.name)

		// It must always parse, and always be an attachment.
		disp, params, err := mime.ParseMediaType(got)
		if err != nil {
			t.Errorf("contentDisposition(%q) = %q: does not parse: %v", c.name, got, err)
			continue
		}
		if disp != "attachment" {
			t.Errorf("contentDisposition(%q): disposition = %q", c.name, disp)
		}
		// Whatever the encoding, the decoded filename must be the real one when
		// an extended parameter is present.
		if c.wantExt {
			if !strings.Contains(got, "filename*=UTF-8''") {
				t.Errorf("contentDisposition(%q) = %q: no RFC 5987 parameter", c.name, got)
			}
			if params["filename"] != c.name {
				t.Errorf("contentDisposition(%q): decoded filename = %q", c.name, params["filename"])
			}
		} else if params["filename"] != c.wantASCII {
			t.Errorf("contentDisposition(%q): filename = %q, want %q", c.name, params["filename"], c.wantASCII)
		}

		// Nothing may break out of the header, in any spelling.
		if strings.ContainsAny(got, "\r\n") {
			t.Errorf("contentDisposition(%q) = %q: contains a line break", c.name, got)
		}
		if i := strings.Index(got, `filename="`); i >= 0 {
			quoted := got[i+len(`filename="`):]
			quoted = quoted[:strings.Index(quoted, `"`)]
			if strings.ContainsAny(quoted, `"\`) {
				t.Errorf("contentDisposition(%q): unescaped quoting in %q", c.name, quoted)
			}
		}
	}
}

func TestASCIIFilenameNeverEmpty(t *testing.T) {
	for _, in := range []string{"", "...", "___", "   ", "🙂"} {
		if got := asciiFilename(in); strings.Trim(got, "_. ") == "" {
			t.Errorf("asciiFilename(%q) = %q, which names nothing", in, got)
		}
	}
}

func TestEncodeRFC5987(t *testing.T) {
	cases := map[string]string{
		"plain.txt": "plain.txt",
		"a b.txt":   "a%20b.txt",
		"naïve":     "na%C3%AFve",
		`q"x`:       "q%22x",
	}
	for in, want := range cases {
		if got := encodeRFC5987(in); got != want {
			t.Errorf("encodeRFC5987(%q) = %q, want %q", in, got, want)
		}
	}
}