package accounts

import (
	"context"
	"errors"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"github.com/novox/mesh-host/internal/declaration"
)

// The account judge (novox/hq ADR 0252, "how it is checked"): an account in a group its running session
// lacks is unhealthy with "relogin needed"; the same account with no session, or a session that has the
// group, is healthy; one the database does not list in the group is unhealthy saying so; and everything
// asked of the machine is a read.

// machine is a fake: the database's groups, the manager's process and its status file.
type machine struct {
	t       *testing.T
	proc    string
	inDB    string
	pid     string
	held    string // the Groups line of the manager's status
	asked   []string
	failsID bool
}

func (m *machine) run(_ context.Context, name string, args ...string) (string, error) {
	m.asked = append(m.asked, name+" "+strings.Join(args, " "))
	switch {
	case name == "id":
		if m.failsID {
			return "", errors.New("id exited 1")
		}
		return m.inDB + "\n", nil
	case name == "getent" && args[0] == "passwd":
		return "operator:x:1500:1500::/home/operator:/bin/zsh\n", nil
	case name == "getent" && args[0] == "group":
		switch args[1] {
		case "openrazer":
			return "openrazer:x:964:operator\n", nil
		case "wheel":
			return "wheel:x:998:operator\n", nil
		}
		return "", errors.New("getent exited 2: ")
	case name == "systemctl":
		return m.pid + "\n", nil
	}
	return "", errors.New("not a command the judge may run")
}

func (m *machine) status() {
	m.t.Helper()
	if m.pid == "" || m.pid == "0" {
		return
	}
	dir := filepath.Join(m.proc, m.pid)
	if err := os.MkdirAll(dir, 0o755); err != nil {
		m.t.Fatal(err)
	}
	body := "Name:\tsystemd\nUid:\t1500\t1500\t1500\t1500\nGid:\t1500\t1500\t1500\t1500\nGroups:\t" + m.held + "\n"
	if err := os.WriteFile(filepath.Join(dir, "status"), []byte(body), 0o644); err != nil {
		m.t.Fatal(err)
	}
}

var razer = Account{Module: "openrazer", ID: "openrazer.account", Name: "operator", Groups: []string{"openrazer"}}

func look(t *testing.T, m *machine) Verdict {
	t.Helper()
	m.status()
	j := New(Exec{Run: m.run, Proc: m.proc})
	j.Now = func() time.Time { return time.Date(2026, 10, 8, 12, 0, 0, 0, time.UTC) }
	j.Set([]Account{razer})
	st, _ := j.Look(t.Context())
	if len(st.Accounts) != 1 {
		t.Fatalf("the statement: %+v", st)
	}
	return st.Accounts[0]
}

func TestAGroupTheRunningSessionLacksSaysReloginNeeded(t *testing.T) {
	m := &machine{t: t, proc: t.TempDir(), inDB: "operator wheel openrazer", pid: "4242", held: "998"}
	v := look(t, m)
	if v.State != Unhealthy || !strings.HasPrefix(v.Reason, ReasonRelogin) || !strings.Contains(v.Reason, "openrazer") ||
		!strings.Contains(v.Reason, "log out") {
		t.Fatalf("a session without the group: %+v", v)
	}
	if v.Module != "openrazer" || v.ID != "openrazer.account" {
		t.Errorf("the verdict is not the module's: %+v", v)
	}
	for _, a := range m.asked {
		read := strings.HasPrefix(a, "id -nG ") || strings.HasPrefix(a, "getent ") ||
			strings.HasPrefix(a, "systemctl show --property=MainPID --value user@")
		if !read {
			t.Errorf("the judge asked something that is not a read: %q", a)
		}
	}
}

func TestASessionThatHasTheGroupIsHealthy(t *testing.T) {
	m := &machine{t: t, proc: t.TempDir(), inDB: "operator wheel openrazer", pid: "4242", held: "998 964"}
	if v := look(t, m); v.State != Healthy || v.Reason != "" {
		t.Fatalf("a session with the group: %+v", v)
	}
}

func TestNoSessionIsHealthyTheNextLoginTakesTheGroup(t *testing.T) {
	m := &machine{t: t, proc: t.TempDir(), inDB: "operator openrazer", pid: "0"}
	if v := look(t, m); v.State != Healthy {
		t.Fatalf("no session: %+v", v)
	}
}

func TestAnAccountTheDatabaseDoesNotListIsUnhealthySayingSo(t *testing.T) {
	m := &machine{t: t, proc: t.TempDir(), inDB: "operator wheel", pid: "4242", held: "998"}
	v := look(t, m)
	if v.State != Unhealthy || !strings.HasPrefix(v.Reason, "not in the group openrazer") {
		t.Fatalf("not in the group: %+v", v)
	}
}

func TestADatabaseThatDoesNotAnswerIsUnknownNeverHealthy(t *testing.T) {
	m := &machine{t: t, proc: t.TempDir(), failsID: true}
	if v := look(t, m); v.State != Unknown {
		t.Fatalf("an unread database: %+v", v)
	}
}

func TestOnlyAModulesAccountWithGroupsIsJudged(t *testing.T) {
	d, err := declaration.ParseTrusted([]byte(`{"declaration":1,"resources":[
	  {"id":"zsh.login","type":"user","name":"operator","shell":"/bin/zsh"},
	  {"id":"openrazer.account","type":"user","name":"operator","groups":["openrazer"]},
	  {"id":"docker.account","type":"user","name":"operator","groups":["docker"]},
	  {"id":"meshown","type":"user","name":"mesh","groups":["x"]}
	]}`))
	if err != nil {
		t.Fatal(err)
	}
	got := Of(d, map[string]bool{"docker.account": true})
	if len(got) != 1 || got[0].ID != "openrazer.account" || got[0].Module != "openrazer" {
		t.Fatalf("judged: %+v", got)
	}
}

func TestAVerdictThatHoldsCountsItsStreakAndAChangeIsSaid(t *testing.T) {
	m := &machine{t: t, proc: t.TempDir(), inDB: "operator openrazer", pid: "4242", held: "998"}
	m.status()
	j := New(Exec{Run: m.run, Proc: m.proc})
	j.Set([]Account{razer})
	_, changed := j.Look(t.Context())
	st, again := j.Look(t.Context())
	if !changed || again || st.Accounts[0].Streak != 2 {
		t.Fatalf("first look changed %v, second %v, streak %d", changed, again, st.Accounts[0].Streak)
	}
	m.held = "998 964"
	m.status()
	st, changed = j.Look(t.Context())
	if !changed || st.Accounts[0].State != Healthy || st.Accounts[0].Streak != 0 {
		t.Fatalf("after the new login: changed %v, %+v", changed, st.Accounts[0])
	}
}