package host

import (
	"context"
	"encoding/json"
	"errors"
	"testing"

	"github.com/carlosframework/platform/internal/release"
)

func TestParseMemAvailable(t *testing.T) {
	const meminfo = "MemTotal:       16000000 kB\nMemFree:          500000 kB\nMemAvailable:    2263040 kB\n"
	if got := parseMemAvailableMiB(meminfo); got != 2210 {
		t.Fatalf("got %d, want 2210", got)
	}
	if got := parseMemAvailableMiB("MemTotal: 1 kB\n"); got != 0 {
		t.Fatalf("no MemAvailable line: got %d, want 0", got)
	}
	if got := parseMemAvailableMiB("MemAvailable: lots kB\n"); got != 0 {
		t.Fatalf("unparseable: got %d, want 0", got)
	}
}

func TestHeadroomOnlyPublishedWithTheCapability(t *testing.T) {
	reg := edgesTestRegistry(t)
	if got := headroomFor(nil, t.TempDir(), reg); got != nil {
		t.Fatalf("flag off: headroom = %+v, want nil", got)
	}
	if got := headroomFor([]string{capRegionHA1}, t.TempDir(), reg); got == nil {
		t.Fatal("flag on: headroom is nil")
	}
}

// Region HA spec 2 §7: the totals ride beside the free figures, and a
// failed reading is 0, never a guess.
func TestCapacityMiBReadsTotalsAndZeroesFailures(t *testing.T) {
	gib := int64(8 << 30)
	mem := func() (*int64, *int64) { return &gib, nil }
	disk := func() (uint64, uint64, error) { return 100 << 30, 1 << 30, nil }
	if m, d := capacityMiB(mem, disk); m != 8192 || d != 102400 {
		t.Fatalf("capacity = %d, %d; want 8192, 102400", m, d)
	}
	noMem := func() (*int64, *int64) { return nil, nil }
	noDisk := func() (uint64, uint64, error) { return 0, 0, errors.New("statfs") }
	if m, d := capacityMiB(noMem, noDisk); m != 0 || d != 0 {
		t.Fatalf("failed readings = %d, %d; want 0, 0", m, d)
	}
}

func TestHeadroomCarriesTheDataVolumeSize(t *testing.T) {
	h := headroomFor([]string{capRegionHA1}, t.TempDir(), edgesTestRegistry(t))
	if h == nil || h.DiskTotalMiB <= 0 {
		t.Fatalf("headroom %+v: want the data volume's size", h)
	}
}

func TestEdgesFileWireCarriesHeadroomTotals(t *testing.T) {
	s, reg := release.NewDirStore(t.TempDir()), edgesTestRegistry(t)
	var last []byte
	ident := edgesFile{Box: "annie", BoxID: "i-0abc", Capabilities: []string{"region-ha-1"},
		Headroom: &edgeHeadroom{MemFreeMiB: 2210, DiskFreeMiB: 31200, Awake: 14, MemTotalMiB: 7900, DiskTotalMiB: 61000}}
	if err := edgesFilePass(context.Background(), s, reg, ident, "1.2.3.4", &last); err != nil {
		t.Fatal(err)
	}
	body, _, err := s.Get(context.Background(), "control/edges/annie.json")
	if err != nil {
		t.Fatal(err)
	}
	var raw map[string]json.RawMessage
	if err := json.Unmarshal(body, &raw); err != nil {
		t.Fatal(err)
	}
	if want := `{"mem_free_mib":2210,"disk_free_mib":31200,"awake":14,"mem_total_mib":7900,"disk_total_mib":61000}`; string(raw["headroom"]) != want {
		t.Fatalf("headroom = %s, want %s", raw["headroom"], want)
	}
}