package localapi

import (
	"context"
	"encoding/json"
	"io"
	"log/slog"
	"net/http"
	"testing"

	"gitea.dooplex.hu/admin/felhom-agent/internal/hub"
	"gitea.dooplex.hu/admin/felhom-agent/internal/storage"
)

// POST /disks/same-disk (`16` §4) — the controller's Tier-2 question, answered from the agent's own read.

type fakeIdentHost struct {
	mounts []storage.Mount
	parent map[string]string
	props  map[string]map[string]string
	virt   string
}

func (f *fakeIdentHost) Mounts() ([]storage.Mount, error) { return f.mounts, nil }
func (f *fakeIdentHost) KernelName(dev string) (string, bool) {
	if len(dev) > 5 && dev[:5] == "/dev/" {
		return dev[5:], true
	}
	return "", false
}
func (f *fakeIdentHost) Parent(n string) (string, bool)        { p, ok := f.parent[n]; return p, ok }
func (f *fakeIdentHost) Slaves(string) []string                { return nil }
func (f *fakeIdentHost) LoopBackingFile(string) (string, bool) { return "", false }
func (f *fakeIdentHost) UdevProps(n string) map[string]string  { return f.props[n] }
func (f *fakeIdentHost) Virt() string                          { return f.virt }

// sameDiskRig: guest 8200 (token A) with mp0 on local-lvm (the system SSD, proven) + the given mounts.
func sameDiskRig(t *testing.T, host *fakeIdentHost, localLVM hub.StorageTarget) http.Handler {
	t.Helper()
	fg := &fakeGuestsCfg{mounts: map[int]map[string]string{8200: {
		"mp0": "local-lvm:vm-8200-disk-1,mp=/var/lib/felhom,backup=1,size=70G",
		"mp8": "/mnt/felhom-drives,mp=/mnt/felhom-drives",
	}}}
	srv, err := NewServer(Options{
		ListenAddr: "127.0.0.1:0", Guests: fg, Backups: &fakeBackups{}, Store: &fakeStore{},
		Storage: fakeStorage{targets: []hub.StorageTarget{localLVM}}, Tokens: staticTokens{"A": 8200},
		HostReader: fakeHostReader{mounts: host.mounts},
		Identity:   &storage.IdentityResolver{Host: host},
		Logger:     slog.New(slog.NewTextHandler(io.Discard, nil)),
	})
	if err != nil {
		t.Fatal(err)
	}
	srv.baseCtx = context.Background()
	return srv.Handler()
}

var provenSSD = hub.StorageTarget{Name: "local-lvm", Type: hub.StorageTypeLVMThin, Kind: "system",
	PhysicalDisks: []string{"serial:ata:SanDisk:1"}, Identity: "proven"}

func baseHost() *fakeIdentHost {
	return &fakeIdentHost{
		virt:   "none",
		parent: map[string]string{"sdc1": "sdc", "sdc2": "sdc"},
		props: map[string]map[string]string{
			"sdb": {"ID_BUS": "ata", "ID_MODEL": "TOSHIBA", "ID_SERIAL_SHORT": "65NOP3HDT"},
			"sdc": {"ID_BUS": "usb", "ID_MODEL": "Portable", "ID_SERIAL_SHORT": "NAAB7C21"},
		},
		mounts: []storage.Mount{
			{Device: "/dev/mapper/pve-root", MountPoint: "/", FSType: "ext4"},
			{Device: "/dev/mapper/pve-root", MountPoint: "/mnt/felhom-drives", FSType: "ext4"},
			{Device: "/dev/sdb", MountPoint: "/mnt/felhom-drives/hdd_1", FSType: "ext4"},
			{Device: "/dev/sdc1", MountPoint: "/mnt/felhom-drives/a", FSType: "ext4"},
			{Device: "/dev/sdc2", MountPoint: "/mnt/felhom-drives/b", FSType: "ext4"},
			{Device: "//nas/films", MountPoint: "/mnt/felhom-drives/nas", FSType: "cifs"},
		},
	}
}

func sameDisk(t *testing.T, h http.Handler, a, b string) (SameDiskResponse, int) {
	t.Helper()
	body, _ := json.Marshal(map[string]string{"a": a, "b": b})
	w := do(t, h, "POST", "/disks/same-disk", "A", string(body))
	var env struct {
		Data SameDiskResponse `json:"data"`
	}
	_ = json.Unmarshal(w.Body.Bytes(), &env)
	return env.Data, w.Code
}

func TestSameDisk_DriveVsSystemData_DifferentProven(t *testing.T) {
	h := sameDiskRig(t, baseHost(), provenSSD)
	got, code := sameDisk(t, h, "/mnt/felhom-drives/hdd_1/felhom-data/paperless", "/mnt/sys_drive")
	if code != http.StatusOK || !got.Different || !got.Proven || got.Reason != "" {
		t.Fatalf("drive vs sys_drive: want different+proven, got %d %+v", code, got)
	}
	if got.B.Kind != "system" || got.A.Kind != "disk" {
		t.Fatalf("kinds: got a=%q b=%q", got.A.Kind, got.B.Kind)
	}
}

func TestSameDisk_TwoPartitionsOfOneDisk_SameProven(t *testing.T) {
	h := sameDiskRig(t, baseHost(), provenSSD)
	got, _ := sameDisk(t, h, "/mnt/felhom-drives/a", "/mnt/felhom-drives/b/x")
	if got.Different || !got.Proven || got.Reason != "same_disk" || got.A.Kind != "partition" {
		t.Fatalf("two partitions: want same+proven, got %+v", got)
	}
}

func TestSameDisk_InsideAVM_NotProven(t *testing.T) {
	host := baseHost()
	host.virt = "kvm"
	h := sameDiskRig(t, host, hub.StorageTarget{Name: "local-lvm", Identity: "unknown", IdentityReason: "vm",
		PhysicalDisks: []string{"serial:scsi:QEMU_HARDDISK:drive-scsi0"}})
	got, _ := sameDisk(t, h, "/mnt/felhom-drives/hdd_1", "/mnt/sys_drive")
	if got.Proven || got.Reason != "vm" {
		t.Fatalf("inside a VM: want not proven (vm), got %+v", got)
	}
}

func TestSameDisk_NetworkAndUnmapped(t *testing.T) {
	h := sameDiskRig(t, baseHost(), provenSSD)
	if got, _ := sameDisk(t, h, "/mnt/felhom-drives/nas", "/mnt/sys_drive"); got.Proven || got.Reason != "network" {
		t.Fatalf("a NAS: want not proven (network), got %+v", got)
	}
	// An ABSENT drive: its directory sits on the root disk — must be unmapped, never "the system disk".
	if got, _ := sameDisk(t, h, "/mnt/felhom-drives/gone", "/mnt/sys_drive"); got.Proven || got.Reason != "unmapped" || got.A.Mapped {
		t.Fatalf("an absent drive: want unmapped, got %+v", got)
	}
	if got, _ := sameDisk(t, h, "/opt/elsewhere", "/mnt/sys_drive"); got.Proven || got.Reason != "unmapped" {
		t.Fatalf("an unknown guest path: want unmapped, got %+v", got)
	}
}

func TestSameDisk_ScopedAndValidated(t *testing.T) {
	h := sameDiskRig(t, baseHost(), provenSSD)
	if w := do(t, h, "POST", "/disks/same-disk", "A", `{"vmid":9300,"a":"/mnt/sys_drive","b":"/mnt/sys_drive"}`); w.Code != http.StatusForbidden {
		t.Fatalf("another guest's vmid: got %d want 403", w.Code)
	}
	if w := do(t, h, "POST", "/disks/same-disk", "A", `{"a":"relative","b":"/mnt/sys_drive"}`); w.Code != http.StatusBadRequest {
		t.Fatalf("a relative path: got %d want 400", w.Code)
	}
	if w := do(t, h, "POST", "/disks/same-disk", "", `{"a":"/x","b":"/y"}`); w.Code != http.StatusUnauthorized {
		t.Fatalf("no token: got %d want 401", w.Code)
	}
}