package restorespace

import (
	"context"
	"errors"
	"testing"

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

// R-672 (v0.133.0). The provider behind the restore-test's space preflight. No test reaches a real
// Proxmox or a real file: the API and ReadFile are fakes.

type fakeAPI struct {
	cfg     []proxmox.Storage
	live    []proxmox.Storage
	content map[string][]proxmox.StorageContent
	perms   map[string]map[string]int
}

func (f fakeAPI) ListStorage(context.Context) ([]proxmox.Storage, error) { return f.cfg, nil }
func (f fakeAPI) NodeStorage(context.Context) ([]proxmox.Storage, error) { return f.live, nil }
func (f fakeAPI) StorageContent(_ context.Context, s string) ([]proxmox.StorageContent, error) {
	return f.content[s], nil
}
func (f fakeAPI) Permissions(_ context.Context, p string) (map[string]int, error) {
	if m, ok := f.perms[p]; ok {
		return m, nil
	}
	return map[string]int{}, nil
}

const archive = "local:backup/vzdump-lxc-9201-2026_09_23-06_55_25.tar.zst"

// The real log's tail (demo-hp, 2026-09-23): 22.6 GB written, a 6.91 GB archive file.
const vzdumpLog = "2026-09-23 07:02:47 INFO: Total bytes written: 22607360000 (22GiB, 49MiB/s)\n2026-09-23 07:02:47 INFO: archive file size: 6.91GB\n"

// demoHP is demo-hp's storage layout: `local` (dir, backups), `local-lvm` (thin), `nvme-scratch` (dir,
// rootdir — but the agent holds NO grant there), a pbs.
func demoHP() fakeAPI {
	return fakeAPI{
		cfg: []proxmox.Storage{
			{Storage: "local", Type: "dir", Path: "/var/lib/vz"},
			{Storage: "local-lvm", Type: "lvmthin", VGName: "pve", ThinPool: "data"},
			{Storage: "nvme-scratch", Type: "dir", Path: "/mnt/hdd_1"},
			{Storage: "felhom-pbs", Type: "pbs"},
		},
		live: []proxmox.Storage{
			{Storage: "local", Type: "dir", Content: "vztmpl,backup,iso,import", Active: 1, Avail: 4 << 30, Used: 34 << 30},
			{Storage: "local-lvm", Type: "lvmthin", Content: "images,rootdir", Active: 1, Avail: 23210892 * 1024, Used: 33277043 * 1024},
			{Storage: "nvme-scratch", Type: "dir", Content: "images,rootdir", Active: 1, Avail: 800 << 30},
			{Storage: "felhom-pbs", Type: "pbs", Content: "backup", Active: 0},
		},
		content: map[string][]proxmox.StorageContent{
			"local":      {{VolID: archive, Size: 7417540996}},
			"felhom-pbs": {{VolID: "felhom-pbs:backup/ct/9201/2026-09-23T02:00:00Z", Size: 21 << 30}},
		},
		perms: map[string]map[string]int{
			"/storage/local":     {"Datastore.Audit": 1, "Datastore.AllocateSpace": 1},
			"/storage/local-lvm": {"Datastore.Audit": 1, "Datastore.AllocateSpace": 1},
			// nvme-scratch: only the inherited box-wide Datastore.Audit — the trap proxmox.Permissions names.
			"/storage/nvme-scratch": {"Datastore.Audit": 1},
		},
	}
}

// TestRestoredBytes_ReadsTheUncompressedSize — the vzdump log's "Total bytes written", never the archive
// FILE size (6.9 GB for a 22.6 GB restore).
//
// COMPANION RED-PROOF (REPORT): return the storage content's Size for a dir storage → 7417540996, and
// this test fails at "the compressed file size was used".
func TestRestoredBytes_ReadsTheUncompressedSize(t *testing.T) {
	var asked string
	p := &Provider{API: demoHP(), ReadFile: func(n string) ([]byte, error) { asked = n; return []byte(vzdumpLog), nil }}
	n, src, err := p.RestoredBytes(context.Background(), archive)
	if err != nil {
		t.Fatal(err)
	}
	if n == 7417540996 {
		t.Fatal("the compressed file size was used — the restore writes 3× that")
	}
	if n != 22607360000 || asked != "/var/lib/vz/dump/vzdump-lxc-9201-2026_09_23-06_55_25.log" {
		t.Fatalf("n=%d from %q (log %q)", n, src, asked)
	}
}

func TestRestoredBytes_UnknownIsAnError(t *testing.T) {
	cases := map[string]*Provider{
		"no log":           {API: demoHP(), ReadFile: func(string) ([]byte, error) { return nil, errors.New("ENOENT") }},
		"log without size": {API: demoHP(), ReadFile: func(string) ([]byte, error) { return []byte("ERROR: failed\n"), nil }},
	}
	for name, p := range cases {
		if n, _, err := p.RestoredBytes(context.Background(), archive); err == nil {
			t.Fatalf("%s: got %d, want an error (the preflight then refuses)", name, n)
		}
	}
	if _, _, err := (&Provider{API: demoHP()}).RestoredBytes(context.Background(), "local:backup/weird.vma"); err == nil {
		t.Fatal("an unknown archive suffix must be an error")
	}
}

func TestRestoredBytes_PBS(t *testing.T) {
	p := &Provider{API: demoHP()}
	n, _, err := p.RestoredBytes(context.Background(), "felhom-pbs:backup/ct/9201/2026-09-23T02:00:00Z")
	if err != nil || n != 21<<30 {
		t.Fatalf("n=%d err=%v", n, err)
	}
}

// TestEligible_NeedsTheSpecificGrant — nvme-scratch takes rootdir but the agent holds only the inherited
// Datastore.Audit there, so it is NOT eligible; `local` holds no rootdir.
func TestEligible_NeedsTheSpecificGrant(t *testing.T) {
	got, err := (&Provider{API: demoHP()}).Eligible(context.Background())
	if err != nil || len(got) != 1 || got[0] != "local-lvm" {
		t.Fatalf("eligible = %v (%v) — want only local-lvm on demo-hp", got, err)
	}
}

func TestFree_ThinCarriesMetadata(t *testing.T) {
	p := &Provider{API: demoHP(), ThinMeta: func(_ context.Context, vg, pool string) (float64, bool) {
		if vg != "pve" || pool != "data" {
			t.Fatalf("metadata read for %s/%s", vg, pool)
		}
		return 0.0265, true
	}}
	fr, err := p.Free(context.Background(), "local-lvm")
	if err != nil || !fr.Thin || !fr.MetaKnown || fr.MetaUsedFraction != 0.0265 || fr.AvailBytes != 23210892*1024 {
		t.Fatalf("free = %+v err=%v", fr, err)
	}
	if _, err := p.Free(context.Background(), "felhom-pbs"); err == nil {
		t.Fatal("an inactive storage must be an error")
	}
}