package syncer

import (
	"strings"
	"testing"

	"idsync/internal/ldaplib"
	"idsync/internal/mapping"
)

const (
	peopleOU   = "ou=people,dc=example,dc=com"
	groupRoot  = "ou=groups,dc=example,dc=com"
	testAdmin  = "uid=admin," + peopleOU
)

func entry(dn string, attrs map[string]string, members []string) *ldaplib.Entry {
	return ldaplib.NewEntry(dn, attrs, members)
}

func dUser(uid string) *mapping.DesiredUser {
	return &mapping.DesiredUser{
		UID: uid, DN: "uid=" + uid + "," + peopleOU,
		Mail: uid + "@example.com", DisplayName: uid, GivenName: uid, SN: uid,
	}
}

func dGroup(deptID, dn string, members ...string) *mapping.DesiredGroup {
	ms := make(map[string]struct{}, len(members))
	for _, m := range members {
		ms[m] = struct{}{}
	}
	return &mapping.DesiredGroup{DeptID: deptID, DN: dn, Name: depName(deptID), Members: ms}
}

func depName(deptID string) string { return "部门-" + deptID }

func baseIn(desired *mapping.DesiredState) *Input {
	return &Input{
		Desired:      desired,
		ActualUsers:  map[string]*ldaplib.Entry{},
		ActualGroups: map[string]*ldaplib.Entry{},
		OwnedUsers:   map[string]struct{}{},
		ConfirmedLeave: map[string]bool{},
		AdminDN:      testAdmin,
		PeopleOU:     peopleOU,
		GroupRootDN:  groupRoot,
	}
}

func kindsOf(plan *Plan) map[OpKind]int {
	out := make(map[OpKind]int)
	for _, op := range plan.Ops {
		out[op.Kind]++
	}
	return out
}

func plainDesired() *mapping.DesiredState {
	return &mapping.DesiredState{Users: []*mapping.DesiredUser{}, Groups: []*mapping.DesiredGroup{}}
}

func TestComputePlan(t *testing.T) {
	rdDN := "cn=od-rd," + groupRoot
	tests := []struct {
		name      string
		desired   *mapping.DesiredState
		mutate    func(in *Input)
		wantKinds map[OpKind]int
		forbid    []OpKind
		wantWarn  string
	}{
		{
			name:    "全新用户：创建",
			desired: withUsers(plainDesired(), dUser("alice")),
			wantKinds: map[OpKind]int{OpCreateUser: 1},
		},
		{
			name:    "属性一致：不产生操作",
			desired: withUsers(plainDesired(), dUser("alice")),
			mutate: func(in *Input) {
				u := dUser("alice")
				in.ActualUsers["alice"] = entry(u.DN, map[string]string{
					ldaplib.AttrMail: u.Mail, ldaplib.AttrDisplayName: u.DisplayName,
					ldaplib.AttrGivenName: u.GivenName, ldaplib.AttrSN: u.SN,
				}, nil)
				in.OwnedUsers["alice"] = struct{}{}
			},
			wantKinds: map[OpKind]int{},
		},
		{
			name:    "邮箱变化：更新属性",
			desired: withUsers(plainDesired(), func() *mapping.DesiredUser { u := dUser("alice"); u.Mail = "new@example.com"; return u }()),
			mutate: func(in *Input) {
				in.ActualUsers["alice"] = entry("uid=alice,"+peopleOU, map[string]string{
					ldaplib.AttrMail: "old@example.com", ldaplib.AttrDisplayName: "alice",
					ldaplib.AttrGivenName: "alice", ldaplib.AttrSN: "alice",
				}, nil)
				in.OwnedUsers["alice"] = struct{}{}
			},
			wantKinds: map[OpKind]int{OpUpdateUser: 1},
		},
		{
			name:    "在 LLDAP、台账、已确认离职，但不在期望：删除",
			desired: plainDesired(),
			mutate: func(in *Input) {
				in.ActualUsers["bob"] = entry("uid=bob,"+peopleOU, map[string]string{
					ldaplib.AttrDisplayName: "Bob"}, nil)
				in.OwnedUsers["bob"] = struct{}{}
				in.ConfirmedLeave["bob"] = true
			},
			wantKinds: map[OpKind]int{OpDeleteUser: 1},
		},
		{
			name:    "在 LLDAP、台账，但未确认离职：绝不删除（关键安全回归）",
			desired: plainDesired(),
			mutate: func(in *Input) {
				in.ActualUsers["bob"] = entry("uid=bob,"+peopleOU, map[string]string{}, nil)
				in.OwnedUsers["bob"] = struct{}{}
			},
			wantKinds: map[OpKind]int{},
			forbid:    []OpKind{OpDeleteUser},
			wantWarn:  "未完成离职确认",
		},
		{
			name:    "在 LLDAP、非受管（服务账号）：绝不删除",
			desired: plainDesired(),
			mutate: func(in *Input) {
				in.ActualUsers["svc"] = entry("uid=svc,"+peopleOU, map[string]string{}, nil)
				in.ConfirmedLeave["svc"] = true // 即使被标记也无效：非受管
			},
			wantKinds: map[OpKind]int{},
			forbid:    []OpKind{OpDeleteUser},
		},
		{
			name:    "分组不存在：创建",
			desired: withGroups(plainDesired(), dGroup("od-rd", rdDN)),
			wantKinds: map[OpKind]int{OpCreateGroup: 1},
		},
		{
			name:    "孤儿组（actual 有、期望没有）：不删只告警",
			desired: plainDesired(),
			mutate: func(in *Input) {
				in.ActualGroups[strings.ToLower(rdDN)] = entry("cn=od-rd,"+groupRoot,
					map[string]string{ldaplib.AttrDescription: "x"}, nil)
			},
			wantKinds: map[OpKind]int{},
			forbid:    []OpKind{OpCreateGroup},
			wantWarn:  "未自动删除",
		},
		{
			name:    "成员缺席：加入分组",
			desired: withGroups(plainDesired(), dGroup("od-rd", rdDN, "uid=alice,"+peopleOU)),
			mutate: func(in *Input) {
				in.ActualGroups[strings.ToLower(rdDN)] = entry("cn=od-rd,"+groupRoot, nil, nil)
				in.OwnedUsers["alice"] = struct{}{}
			},
			wantKinds: map[OpKind]int{OpAddMember: 1},
		},
		{
			name:    "成员多余且受管：移出分组",
			desired: withGroups(plainDesired(), dGroup("od-rd", rdDN)),
			mutate: func(in *Input) {
				in.ActualGroups[strings.ToLower(rdDN)] = entry("cn=od-rd,"+groupRoot, nil,
					[]string{testAdmin, "uid=alice," + peopleOU})
				in.OwnedUsers["alice"] = struct{}{}
			},
			wantKinds: map[OpKind]int{OpRemoveMember: 1},
		},
		{
			name:    "admin 永不被移出分组（关键安全回归）",
			desired: withGroups(plainDesired(), dGroup("od-rd", rdDN)),
			mutate: func(in *Input) {
				in.ActualGroups[strings.ToLower(rdDN)] = entry("cn=od-rd,"+groupRoot, nil,
					[]string{testAdmin})
				in.OwnedUsers["admin"] = struct{}{}
			},
			wantKinds: map[OpKind]int{},
			forbid:    []OpKind{OpRemoveMember},
		},
		{
			name:    "外部非受管成员：不移出，仅告警",
			desired: withGroups(plainDesired(), dGroup("od-rd", rdDN)),
			mutate: func(in *Input) {
				in.ActualGroups[strings.ToLower(rdDN)] = entry("cn=od-rd,"+groupRoot, nil,
					[]string{testAdmin, "uid=external," + peopleOU})
			},
			wantKinds: map[OpKind]int{},
			forbid:    []OpKind{OpRemoveMember},
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			in := baseIn(tt.desired)
			if tt.mutate != nil {
				tt.mutate(in)
			}
			plan := ComputePlan(in)
			got := kindsOf(plan)
			for kind, want := range tt.wantKinds {
				if got[kind] != want {
					t.Errorf("操作 %s 数量 = %d, 期望 %d\n%s", kind, got[kind], want, dumpPlan(plan))
				}
			}
			for kind, count := range got {
				if _, exp := tt.wantKinds[kind]; !exp {
					t.Errorf("出现未预期的操作 %s (%d)\n%s", kind, count, dumpPlan(plan))
				}
			}
			for _, kind := range tt.forbid {
				if got[kind] > 0 {
					t.Errorf("出现被禁止的操作 %s\n%s", kind, dumpPlan(plan))
				}
			}
			if tt.wantWarn != "" {
				found := false
				for _, w := range plan.Warnings {
					if strings.Contains(w, tt.wantWarn) {
						found = true
						break
					}
				}
				if !found {
					t.Errorf("期望有告警包含 %q，实际: %v", tt.wantWarn, plan.Warnings)
				}
			}
		})
	}
}

// TestDeleteIsLastPhase 验证删除永远排在最后阶段（操作顺序的硬约束）。
func TestDeleteIsLastPhase(t *testing.T) {
	rdDN := "cn=od-rd," + groupRoot
	desired := withUsers(withGroups(plainDesired(), dGroup("od-rd", rdDN, "uid=alice,"+peopleOU)), dUser("alice"))
	in := baseIn(desired)
	in.ActualUsers["alice"] = entry(dUser("alice").DN, map[string]string{
		ldaplib.AttrDisplayName: "alice"}, nil)
	in.OwnedUsers["alice"] = struct{}{}
	in.OwnedUsers["bob"] = struct{}{}
	in.ActualUsers["bob"] = entry("uid=bob,"+peopleOU, map[string]string{}, nil)
	in.ConfirmedLeave["bob"] = true
	in.OwnedUsers["carol"] = struct{}{}
	in.ActualUsers["carol"] = entry("uid=carol,"+peopleOU, map[string]string{}, nil)
	in.ActualGroups[strings.ToLower(rdDN)] = entry("cn=od-rd,"+groupRoot, nil, []string{testAdmin, "uid=carol," + peopleOU})

	plan := ComputePlan(in)

	// bob：删除；alice 创建；carol 移出分组。
	// 任何删除操作都必须排在任何创建/加/移之后。
	maxOther, minDelete := -1, 1<<30
	for i, op := range plan.Ops {
		if op.Kind == OpDeleteUser {
			if i < minDelete {
				minDelete = i
			}
		} else {
			if i > maxOther {
				maxOther = i
			}
		}
	}
	if minDelete <= maxOther {
		t.Errorf("删除操作没有排在最后：delete at %d, other at %d\n%s", minDelete, maxOther, dumpPlan(plan))
	}
}

// TestComputePlanNeverTouchesPassword 是结构性回归：
// 计划中不能出现改写 userPassword 的操作——密码 LLDAP 独占，程序绝不碰。
func TestComputePlanNeverTouchesPassword(t *testing.T) {
	in := baseIn(withUsers(plainDesired(), dUser("alice")))
	plan := ComputePlan(in)
	for _, op := range plan.Ops {
		if strings.Contains(strings.ToLower(op.Detail), "userpassword") ||
			strings.Contains(strings.ToLower(op.Detail), "password") {
			t.Errorf("计划出现涉及密码的操作: %s", op.Detail)
		}
	}
}

func TestGuard(t *testing.T) {
	tests := []struct {
		name    string
		guard   Guard
		plan    *Plan
		wantErr bool
	}{
		{"无删除时通过", Guard{MaxDeactivatePercent: 0.2}, &Plan{Stats: Stats{DeleteUser: 0, TotalUsers: 100}}, false},
		{"超过绝对上限被拒", Guard{MaxDeactivate: 5}, &Plan{Stats: Stats{DeleteUser: 6, TotalUsers: 100}}, true},
		{"超过比例上限被拒", Guard{MaxDeactivatePercent: 0.2}, &Plan{Stats: Stats{DeleteUser: 30, TotalUsers: 100}}, true},
		{"比例在阈值内通过", Guard{MaxDeactivatePercent: 0.2}, &Plan{Stats: Stats{DeleteUser: 10, TotalUsers: 100}}, false},
		{"强制模式跳过", Guard{MaxDeactivate: 1, AllowBulk: true}, &Plan{Stats: Stats{DeleteUser: 50, TotalUsers: 100}}, false},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			err := tt.guard.Check(tt.plan)
			if tt.wantErr && err == nil {
				t.Errorf("期望报错，实际通过")
			}
			if !tt.wantErr && err != nil {
				t.Errorf("期望通过，实际报错: %v", err)
			}
		})
	}
}

func withUsers(s *mapping.DesiredState, us ...*mapping.DesiredUser) *mapping.DesiredState {
	s.Users = append(s.Users, us...)
	return s
}

func withGroups(s *mapping.DesiredState, gs ...*mapping.DesiredGroup) *mapping.DesiredState {
	s.Groups = append(s.Groups, gs...)
	if s.GroupByDeptID == nil {
		s.GroupByDeptID = map[string]*mapping.DesiredGroup{}
	}
	for _, g := range gs {
		s.GroupByDeptID[g.DeptID] = g
	}
	return s
}

func dumpPlan(p *Plan) string {
	var b strings.Builder
	for _, op := range p.Ops {
		b.WriteString("\n  [")
		b.WriteString(string(op.Kind))
		b.WriteString("] ")
		b.WriteString(op.Target)
		b.WriteString(": ")
		b.WriteString(op.Detail)
	}
	for _, w := range p.Warnings {
		b.WriteString("\n  WARN ")
		b.WriteString(w)
	}
	return b.String()
}