package notices

import (
	"context"
	"database/sql"
	"errors"
	"sync"
	"testing"
	"time"
)

// fakeMailer 记录每次 Send 调用,便于断言收件人集合与失败模拟。
type fakeMailer struct {
	mu     sync.Mutex
	sent   []string // to
	failTo map[string]bool
}

func (f *fakeMailer) Send(ctx context.Context, to, subject, body string) error {
	f.mu.Lock()
	defer f.mu.Unlock()
	if f.failTo != nil && f.failTo[to] {
		return errors.New("fake smtp send failure")
	}
	f.sent = append(f.sent, to)
	return nil
}

type auditRow struct {
	Target string
	Meta   string
}

func auditRows(t *testing.T, db *sql.DB, action string) []auditRow {
	t.Helper()
	rows, err := db.Query(`SELECT target, COALESCE(meta,'') FROM audit_log WHERE action=? ORDER BY id`, action)
	if err != nil {
		t.Fatal(err)
	}
	defer rows.Close()
	var out []auditRow
	for rows.Next() {
		var r auditRow
		if err := rows.Scan(&r.Target, &r.Meta); err != nil {
			t.Fatal(err)
		}
		out = append(out, r)
	}
	return out
}

func TestPublish_ValidationErrors(t *testing.T) {
	db := openDB(t)
	st := NewStore(db)
	svc := NewService(st, nil, db)
	ctx := context.Background()

	cases := []struct {
		name string
		in   PublishInput
	}{
		{"bad type", PublishInput{Type: "spam", TitleZH: "标题", TitleEN: "title"}},
		{"empty title zh", PublishInput{Type: "news", TitleZH: "", TitleEN: "title"}},
		{"empty title en", PublishInput{Type: "news", TitleZH: "标题", TitleEN: ""}},
		{"email non-important", PublishInput{Type: "news", TitleZH: "标题", TitleEN: "title", Email: true}},
	}
	for _, c := range cases {
		t.Run(c.name, func(t *testing.T) {
			if _, err := svc.Publish(ctx, c.in); err == nil {
				t.Fatalf("want error, got nil")
			}
		})
	}
}

func TestPublish_SuccessNoEmail(t *testing.T) {
	db := openDB(t)
	seedU(t, db, 1, "u1")
	st := NewStore(db)
	svc := NewService(st, nil, db)
	ctx := context.Background()

	id, err := svc.Publish(ctx, PublishInput{
		Type: "news", TitleZH: "标题", TitleEN: "title", BodyZH: "正文", BodyEN: "body",
	})
	if err != nil {
		t.Fatalf("Publish: %v", err)
	}
	if id == 0 {
		t.Fatalf("want non-zero id")
	}

	items, _, err := st.ListForUser(ctx, 1, time.Now().UTC(), 50)
	if err != nil {
		t.Fatal(err)
	}
	found := false
	for _, it := range items {
		if it.ID == id {
			found = true
		}
	}
	if !found {
		t.Fatalf("published notice not visible via ListForUser: %+v", items)
	}

	rows := auditRows(t, db, "notice_publish")
	if len(rows) != 1 {
		t.Fatalf("want 1 audit row, got %d: %+v", len(rows), rows)
	}
}

func TestPublish_EmailImportant_AllActiveUsersNotified(t *testing.T) {
	db := openDB(t)
	seedU(t, db, 1, "u1")
	seedU(t, db, 2, "u2")
	st := NewStore(db)
	mailer := &fakeMailer{}
	svc := NewService(st, mailer, db)
	ctx := context.Background()

	id, err := svc.Publish(ctx, PublishInput{
		Type: "important", TitleZH: "重要通知", TitleEN: "Important notice",
		BodyZH: "维护中", BodyEN: "under maintenance", Email: true,
	})
	if err != nil {
		t.Fatalf("Publish: %v", err)
	}

	mailer.mu.Lock()
	sentCount := len(mailer.sent)
	mailer.mu.Unlock()
	if sentCount != 2 {
		t.Fatalf("want 2 emails sent (all active users), got %d: %+v", sentCount, mailer.sent)
	}

	var emailSentAt sql.NullTime
	if err := db.QueryRow(`SELECT email_sent_at FROM notices WHERE id=?`, id).Scan(&emailSentAt); err != nil {
		t.Fatal(err)
	}
	if !emailSentAt.Valid {
		t.Fatalf("email_sent_at not set after Publish with Email=true")
	}

	// 再次 Publish 是新公告(幂等的是单公告不重发,不是全局):第二条也应各自发全量邮件。
	id2, err := svc.Publish(ctx, PublishInput{
		Type: "important", TitleZH: "第二条", TitleEN: "Second notice", Email: true,
	})
	if err != nil {
		t.Fatalf("Publish #2: %v", err)
	}
	if id2 == id {
		t.Fatalf("want new notice id, got same as first")
	}
	mailer.mu.Lock()
	sentCount2 := len(mailer.sent)
	mailer.mu.Unlock()
	if sentCount2 != 4 {
		t.Fatalf("want 4 emails total after 2nd publish, got %d: %+v", sentCount2, mailer.sent)
	}
}

func TestPublish_EmailSendFailure_ContinuesAndStillMarksSent(t *testing.T) {
	db := openDB(t)
	seedU(t, db, 1, "u1")
	seedU(t, db, 2, "u2")
	st := NewStore(db)
	mailer := &fakeMailer{failTo: map[string]bool{"u1@x": true}}
	svc := NewService(st, mailer, db)
	ctx := context.Background()

	id, err := svc.Publish(ctx, PublishInput{
		Type: "important", TitleZH: "重要", TitleEN: "Important", Email: true,
	})
	if err != nil {
		t.Fatalf("Publish should not fail even if one recipient's send fails: %v", err)
	}
	mailer.mu.Lock()
	sent := append([]string(nil), mailer.sent...)
	mailer.mu.Unlock()
	if len(sent) != 1 || sent[0] != "u2@x" {
		t.Fatalf("want only u2@x to have succeeded, got %+v", sent)
	}

	var emailSentAt sql.NullTime
	if err := db.QueryRow(`SELECT email_sent_at FROM notices WHERE id=?`, id).Scan(&emailSentAt); err != nil {
		t.Fatal(err)
	}
	if !emailSentAt.Valid {
		t.Fatalf("email_sent_at should still be set after best-effort send attempt")
	}
}

func TestPublish_EmailTrueWithNilMailer_ReturnsError(t *testing.T) {
	db := openDB(t)
	st := NewStore(db)
	svc := NewService(st, nil, db)
	ctx := context.Background()

	if _, err := svc.Publish(ctx, PublishInput{
		Type: "important", TitleZH: "标题", TitleEN: "title", Email: true,
	}); err == nil {
		t.Fatalf("want error when mailer is nil and Email=true")
	}
}

func TestRevokeByID_HidesFromListAndAudits(t *testing.T) {
	db := openDB(t)
	seedU(t, db, 1, "u1")
	st := NewStore(db)
	svc := NewService(st, nil, db)
	ctx := context.Background()

	id, err := svc.Publish(ctx, PublishInput{Type: "news", TitleZH: "标题", TitleEN: "title"})
	if err != nil {
		t.Fatal(err)
	}

	items, _, _ := st.ListForUser(ctx, 1, time.Now().UTC(), 50)
	if len(items) != 1 {
		t.Fatalf("expected notice visible before revoke, got %d", len(items))
	}

	if err := svc.RevokeByID(ctx, id); err != nil {
		t.Fatalf("RevokeByID: %v", err)
	}

	items, _, _ = st.ListForUser(ctx, 1, time.Now().UTC(), 50)
	if len(items) != 0 {
		t.Fatalf("expected no notices visible after revoke, got %+v", items)
	}

	rows := auditRows(t, db, "notice_revoke")
	if len(rows) != 1 {
		t.Fatalf("want 1 audit row for revoke, got %d: %+v", len(rows), rows)
	}
}

func TestRevokeByID_NotFound(t *testing.T) {
	db := openDB(t)
	st := NewStore(db)
	svc := NewService(st, nil, db)
	if err := svc.RevokeByID(context.Background(), 9999); err == nil {
		t.Fatalf("want error for nonexistent notice id")
	}
}