package service

import (
	"context"
	"errors"
	"io"
	"log/slog"
	"strings"
	"testing"
	"time"

	"ws_usernode/internal/model"
)

// recordingMail 捕获邮件发送，用于断言审批通知。
type recordingMail struct {
	lastTo      string
	lastSubject string
	lastBody    string
}

func (m *recordingMail) Send(_ context.Context, to, subject, body string) error {
	m.lastTo = to
	m.lastSubject = subject
	m.lastBody = body
	return nil
}

func testApprovalSvc(t *testing.T) (*ApprovalService, *UserService, *recordingMail) {
	t.Helper()
	db := testDB(t)
	sys := newFakeSys()
	users := NewUserService(db, sys, testConfig())
	mailer := &recordingMail{}
	log := slog.New(slog.NewTextHandler(io.Discard, nil))
	return NewApprovalService(db, testConfig(), users, mailer, log), users, mailer
}

func TestApprovalServiceSubmitValidate(t *testing.T) {
	svc, _, _ := testApprovalSvc(t)
	ctx := context.Background()

	// 非法用户名 / 邮箱
	if _, err := svc.Submit(ctx, "Bad Name", "x@example.com", "", ""); err == nil {
		t.Fatal("invalid username should fail")
	}
	if _, err := svc.Submit(ctx, "okname", "not-an-email", "", ""); err == nil {
		t.Fatal("invalid email should fail")
	}

	// 合法提交
	a, err := svc.Submit(ctx, "zhangsan", "zs@example.com", "prof.li", "科研")
	if err != nil {
		t.Fatalf("submit: %v", err)
	}
	if a.Status != model.StatusPending || a.UsernameRequested != "zhangsan" {
		t.Fatalf("approval = %+v", a)
	}

	// 同名待审批 → 冲突
	if _, err := svc.Submit(ctx, "zhangsan", "z2@example.com", "", ""); !errors.Is(err, ErrUsernameTaken) {
		t.Fatalf("duplicate pending err = %v, want ErrUsernameTaken", err)
	}
}

func TestApprovalServiceReviewApproveCreatesUser(t *testing.T) {
	svc, users, mailer := testApprovalSvc(t)
	ctx := context.Background()

	a, err := svc.Submit(ctx, "lisi", "ls@example.com", "prof.wang", "毕设")
	if err != nil {
		t.Fatalf("submit: %v", err)
	}

	// 拒绝必须填理由
	if _, err := svc.Review(ctx, a.ID, false, 1, "  "); !errors.Is(err, ErrReasonRequired) {
		t.Fatalf("reject without reason err = %v, want ErrReasonRequired", err)
	}

	// 通过 → 自动建号（系统账号 + DB 用户）+ 通知邮件
	got, err := svc.Review(ctx, a.ID, true, 1, "")
	if err != nil {
		t.Fatalf("approve: %v", err)
	}
	if got.Status != model.StatusApproved || got.ReviewerID == nil || *got.ReviewerID != 1 {
		t.Fatalf("approved = %+v", got)
	}
	u, err := users.GetByUsername(ctx, "ext_lisi")
	if err != nil {
		t.Fatalf("user not created: %v", err)
	}
	if u.Status != model.UserStatusActive {
		t.Fatalf("user status = %s", u.Status)
	}
	if mailer.lastTo != "ls@example.com" || !strings.Contains(mailer.lastBody, "ext_lisi") {
		t.Fatalf("approval mail = %s / %s", mailer.lastTo, mailer.lastBody)
	}
	// 默认 TTL（90 天）生效
	if u.ExpireAt == nil || time.Until(*u.ExpireAt) < 80*24*time.Hour {
		t.Fatalf("expire_at = %v", u.ExpireAt)
	}

	// 重复审批 → 冲突
	if _, err := svc.Review(ctx, a.ID, false, 1, "x"); !errors.Is(err, ErrApprovalReviewed) {
		t.Fatalf("re-review err = %v, want ErrApprovalReviewed", err)
	}
	// 用户名已被占用（已建号）→ 新申请冲突
	if _, err := svc.Submit(ctx, "lisi", "x@example.com", "", ""); !errors.Is(err, ErrUsernameTaken) {
		t.Fatalf("resubmit taken err = %v, want ErrUsernameTaken", err)
	}
}

func TestApprovalServiceRejectAndResubmit(t *testing.T) {
	svc, _, mailer := testApprovalSvc(t)
	ctx := context.Background()

	a, err := svc.Submit(ctx, "wangwu", "ww@example.com", "", "")
	if err != nil {
		t.Fatalf("submit: %v", err)
	}
	got, err := svc.Review(ctx, a.ID, false, 1, "用途不明确")
	if err != nil {
		t.Fatalf("reject: %v", err)
	}
	if got.Status != model.StatusRejected || got.Reason != "用途不明确" {
		t.Fatalf("rejected = %+v", got)
	}
	if mailer.lastTo != "ww@example.com" || !strings.Contains(mailer.lastBody, "用途不明确") {
		t.Fatalf("reject mail = %s / %s", mailer.lastTo, mailer.lastBody)
	}

	// 被拒后可重新提交同名申请
	if _, err := svc.Submit(ctx, "wangwu", "ww2@example.com", "", ""); err != nil {
		t.Fatalf("resubmit after reject: %v", err)
	}
	// 不存在 → ErrApprovalNotFound
	if _, err := svc.Review(ctx, 99999, true, 1, ""); !errors.Is(err, ErrApprovalNotFound) {
		t.Fatalf("missing review err = %v, want ErrApprovalNotFound", err)
	}
}

func TestApprovalServiceList(t *testing.T) {
	svc, _, _ := testApprovalSvc(t)
	ctx := context.Background()
	for _, n := range []string{"a1", "a2", "a3"} {
		if _, err := svc.Submit(ctx, n, n+"@example.com", "", ""); err != nil {
			t.Fatalf("submit %s: %v", n, err)
		}
	}
	rows, err := svc.List(ctx, model.StatusPending)
	if err != nil {
		t.Fatalf("list: %v", err)
	}
	if len(rows) != 3 {
		t.Fatalf("pending count = %d, want 3", len(rows))
	}
	// 最新在前
	if rows[0].UsernameRequested != "a3" {
		t.Fatalf("first = %s, want a3", rows[0].UsernameRequested)
	}
	if all, err := svc.List(ctx, ""); err != nil || len(all) != 3 {
		t.Fatalf("list all = %d, %v", len(all), err)
	}
}