package mail

import (
	"strings"
	"testing"
	"time"
)

func TestBuildMIMERoundTrip(t *testing.T) {
	msg := OutgoingMessage{
		From:       "emcli@stevecliff.com",
		To:         []string{"me@stevecliff.com"},
		Cc:         []string{"cc@stevecliff.com"},
		Subject:    "hello from emcli",
		BodyText:   "this is the body\nwith two lines",
		Date:       time.Date(2026, 6, 22, 12, 0, 0, 0, time.UTC),
		InReplyTo:  "abc123@origin.example",
		References: []string{"root@origin.example", "abc123@origin.example"},
		Attachments: []Attachment{
			{Name: "note.txt", MIME: "text/plain", Content: []byte("attached bytes")},
		},
	}

	raw, err := BuildMIME(msg)
	if err != nil {
		t.Fatalf("BuildMIME: %v", err)
	}

	// Headers present in the raw bytes.
	rawStr := string(raw)
	for _, want := range []string{
		"From:", "emcli@stevecliff.com",
		"To:", "me@stevecliff.com",
		"Cc:", "cc@stevecliff.com",
		"Subject:", "hello from emcli",
		"In-Reply-To:", "abc123@origin.example",
		"References:", "root@origin.example",
	} {
		if !strings.Contains(rawStr, want) {
			t.Fatalf("MIME missing %q in:\n%s", want, rawStr)
		}
	}

	// Round-trips back through the parser: body and attachment survive.
	parsed, err := ParseMessage(0, raw)
	if err != nil {
		t.Fatalf("ParseMessage: %v", err)
	}
	gotBody := strings.ReplaceAll(strings.TrimSpace(parsed.BodyText), "\r\n", "\n")
	if gotBody != "this is the body\nwith two lines" {
		t.Fatalf("body not preserved: %q", parsed.BodyText)
	}
	if len(parsed.Attachments) != 1 {
		t.Fatalf("want 1 attachment, got %d", len(parsed.Attachments))
	}
	if parsed.Attachments[0].Name != "note.txt" || string(parsed.Attachments[0].Content) != "attached bytes" {
		t.Fatalf("attachment not preserved: %+v", parsed.Attachments[0])
	}
}

func TestBuildMIMENoAttachments(t *testing.T) {
	msg := OutgoingMessage{
		From:     "emcli@stevecliff.com",
		To:       []string{"me@stevecliff.com"},
		Subject:  "plain",
		BodyText: "just text",
		Date:     time.Date(2026, 6, 22, 12, 0, 0, 0, time.UTC),
	}
	raw, err := BuildMIME(msg)
	if err != nil {
		t.Fatalf("BuildMIME: %v", err)
	}
	parsed, err := ParseMessage(0, raw)
	if err != nil {
		t.Fatalf("ParseMessage: %v", err)
	}
	if strings.TrimSpace(parsed.BodyText) != "just text" {
		t.Fatalf("body not preserved: %q", parsed.BodyText)
	}
	if len(parsed.Attachments) != 0 {
		t.Fatalf("want 0 attachments, got %d", len(parsed.Attachments))
	}
}

func TestRecipientsCombinesAllFields(t *testing.T) {
	msg := OutgoingMessage{
		To:  []string{"a@x.com"},
		Cc:  []string{"b@x.com"},
		Bcc: []string{"c@x.com"},
	}
	got := msg.Recipients()
	want := []string{"a@x.com", "b@x.com", "c@x.com"}
	if len(got) != len(want) {
		t.Fatalf("Recipients()=%v want %v", got, want)
	}
	for i := range want {
		if got[i] != want[i] {
			t.Fatalf("Recipients()=%v want %v", got, want)
		}
	}
}

func TestEnvelopeFromStripsDisplayName(t *testing.T) {
	cases := map[string]string{
		"Steve Cliff <me@stevecliff.com>": "me@stevecliff.com",
		"me@stevecliff.com":               "me@stevecliff.com",
		"<me@stevecliff.com>":             "me@stevecliff.com",
		"not a valid address":             "not a valid address", // unparseable ⇒ passthrough
	}
	for in, want := range cases {
		if got := envelopeFrom(in); got != want {
			t.Fatalf("envelopeFrom(%q) = %q, want %q", in, got, want)
		}
	}
}

func TestBuildMIMEKeepsDisplayNameInHeader(t *testing.T) {
	raw, err := BuildMIME(OutgoingMessage{
		From:     "Steve Cliff <me@stevecliff.com>",
		To:       []string{"you@example.com"},
		Subject:  "hi",
		BodyText: "body",
		Date:     time.Date(2026, 6, 23, 12, 0, 0, 0, time.UTC),
	})
	if err != nil {
		t.Fatalf("BuildMIME: %v", err)
	}
	if !strings.Contains(string(raw), "Steve Cliff") {
		t.Fatalf("From header lost display name:\n%s", raw)
	}
}

func TestReadHeaderParsesReferences(t *testing.T) {
	raw := "From: a@x.com\r\n" +
		"To: b@x.com\r\n" +
		"Subject: re: hi\r\n" +
		"Message-Id: <reply@x.com>\r\n" +
		"References: <root@x.com> <mid@x.com>\r\n" +
		"\r\nbody\r\n"
	h, err := ParseHeaderBytes(7, []byte(raw))
	if err != nil {
		t.Fatalf("ParseHeaderBytes: %v", err)
	}
	if len(h.References) != 2 || h.References[0] != "root@x.com" || h.References[1] != "mid@x.com" {
		t.Fatalf("References not parsed: %v", h.References)
	}
}