package streamdata_test

import (
	"encoding/json"
	"errors"
	"io"
	"os"
	"path"
	"reflect"
	"slices"
	"syscall"
	"testing"
	"time"

	"git.gensokyo.uk/yonah/streamdata"
)

func TestChannelInvalid(t *testing.T) {
	t.Parallel()

	if err := (*streamdata.Channel)(nil).Create(""); !reflect.DeepEqual(err, syscall.EINVAL) {
		t.Fatalf("Create: error = %v", err)
	}
	if err := (*streamdata.Channel)(nil).Close(); !reflect.DeepEqual(err, syscall.EINVAL) {
		t.Fatalf("Close: error = %v", err)
	}
}

func TestChannelOpenPerm(t *testing.T) {
	t.Parallel()

	d := t.TempDir()
	if err := os.Chmod(d, 0); err != nil {
		t.Fatal(err)
	}

	wantErr := &os.PathError{
		Op:   "open",
		Path: d,
		Err:  syscall.EACCES,
	}

	t.Run("open", func(t *testing.T) {
		t.Parallel()

		if _, err := streamdata.Open(d); !reflect.DeepEqual(err, wantErr) {
			t.Fatalf("Open: error = %#v, want %#v", err, wantErr)
		}
	})

	t.Run("create", func(t *testing.T) {
		t.Parallel()

		t.Run("root", func(t *testing.T) {
			t.Parallel()

			if err := (&streamdata.Channel{
				Identifier: 0xcafe,
				Name:       ":3",
			}).Create(d); !reflect.DeepEqual(err, wantErr) {
				t.Fatalf("Create: error = %#v, want %#v", err, wantErr)
			}
		})

		t.Run("mkdir", func(t *testing.T) {
			t.Parallel()

			wantErrMkdir := &os.PathError{
				Op:   "mkdir",
				Path: path.Join(d, "stream"),
				Err:  syscall.EACCES,
			}
			if err := (&streamdata.Channel{
				Identifier: 0xcafe,
				Name:       ":3",
			}).Create(path.Join(d, "stream")); !reflect.DeepEqual(err, wantErrMkdir) {
				t.Fatalf("Create: error = %#v, want %#v", err, wantErrMkdir)
			}
		})

		t.Run("metadata", func(t *testing.T) {
			t.Parallel()

			nx := t.TempDir()
			if err := os.Chmod(nx, 0400); err != nil {
				t.Fatal(err)
			}

			wantErrMetadata := &os.PathError{
				Op:   "openat",
				Path: "channel",
				Err:  syscall.EACCES,
			}
			if err := (&streamdata.Channel{
				Identifier: 0xcafe,
				Name:       ":3",
			}).Create(nx); !reflect.DeepEqual(err, wantErrMetadata) {
				t.Fatalf("Create: error = %#v, want %#v", err, wantErrMetadata)
			}
		})
	})
}

func TestChannelCreate(t *testing.T) {
	t.Parallel()

	d := t.TempDir()
	c := streamdata.Channel{
		Identifier: 0xcafe,
		Name:       ":3",
	}

	if err := c.Create(d); err != nil {
		t.Fatalf("Create: error = %v", err)
	}
	if err := c.Close(); err != nil {
		t.Fatalf("Close: error = %v", err)
	}

	if got, err := streamdata.Open(d); err != nil {
		t.Fatalf("Open: error = %v", err)
	} else if err = got.Close(); err != nil {
		t.Fatalf("Close: error = %v", err)
	} else if !got.Is(&c) {
		t.Errorf("Open: %#v, want %#v", got, c)
	}
}

func TestChannelDangling(t *testing.T) {
	t.Parallel()

	t.Run("dangling", func(t *testing.T) {
		t.Parallel()

		d := t.TempDir()
		if err := os.WriteFile(path.Join(d, "pending"), nil, 0); err != nil {
			t.Fatal(err)
		}
		if _, err := streamdata.Open(d); !reflect.DeepEqual(err, streamdata.ErrDanglingTransaction) {
			t.Errorf("Open: error = %v", err)
		}
	})

	t.Run("perm", func(t *testing.T) {
		t.Parallel()

		d := t.TempDir()
		if err := os.Chmod(d, 0400); err != nil {
			t.Fatal(err)
		}

		wantErr := &os.PathError{
			Op:   "statat",
			Path: "pending",
			Err:  syscall.EACCES,
		}
		if _, err := streamdata.Open(d); !reflect.DeepEqual(err, wantErr) {
			t.Errorf("Open: error = %#v, want %#v", err, wantErr)
		}
	})
}

func TestChannelBadMetadata(t *testing.T) {
	t.Run("perm", func(t *testing.T) {
		t.Parallel()

		d := t.TempDir()
		if err := os.WriteFile(path.Join(d, "channel"), nil, 0); err != nil {
			t.Fatal(err)
		}

		wantErr := &os.PathError{
			Op:   "openat",
			Path: "channel",
			Err:  syscall.EACCES,
		}
		if _, err := streamdata.Open(d); !reflect.DeepEqual(err, wantErr) {
			t.Errorf("Open: error = %#v, want %#v", err, wantErr)
		}
	})

	t.Run("invalid", func(t *testing.T) {
		t.Parallel()

		d := t.TempDir()
		if err := os.WriteFile(path.Join(d, "channel"), nil, 0400); err != nil {
			t.Fatal(err)
		}

		wantErr := io.EOF
		if _, err := streamdata.Open(d); !reflect.DeepEqual(err, wantErr) {
			t.Errorf("Open: error = %#v, want %#v", err, wantErr)
		}
	})
}

func TestChannel(t *testing.T) {
	t.Parallel()

	d := t.TempDir()
	c := streamdata.Channel{
		Identifier: 0xcafe,
		Name:       ":3",
	}

	if err := c.Create(d); err != nil {
		t.Fatalf("Create: error = %v", err)
	}
	t.Cleanup(func() {
		if err := c.Close(); err != nil {
			t.Fatalf("Close: error = %v", err)
		}
	})
	var wantErr error

	if err := c.Add(nil, nil); !reflect.DeepEqual(err, syscall.EINVAL) {
		t.Errorf("(invalid) Add: error = %#v", err)
	}

	wantErr = &streamdata.ChannelMismatchError{
		Got:  0xbabe,
		Want: 0xcafe,
	}
	if err := c.Add(&streamdata.Ident{
		Channel: 0xbabe,
	}, func(*streamdata.VOD, io.Writer) error {
		panic("unreachable")
	}); !reflect.DeepEqual(err, wantErr) {
		t.Fatalf("(channel) Add: error = %#v, want %#v", err, wantErr)
	}

	wantErr = &os.PathError{
		Op:   "openat",
		Path: "pending",
		Err:  syscall.EEXIST,
	}
	if err := os.WriteFile(path.Join(d, "pending"), nil, 0); err != nil {
		t.Fatal(err)
	}
	if err := c.Add(&streamdata.Ident{
		Channel: 0xcafe,
	}, func(*streamdata.VOD, io.Writer) error {
		panic("unreachable")
	}); !reflect.DeepEqual(err, wantErr) {
		t.Fatalf("(create) Add: error = %#v, want %#v", err, wantErr)
	}
	if err := os.Remove(path.Join(d, "pending")); err != nil {
		t.Fatal(err)
	}

	wantErr = errors.New("unique error")
	if err := c.Add(&streamdata.Ident{
		Channel: 0xcafe,
	}, func(*streamdata.VOD, io.Writer) error {
		return wantErr
	}); !reflect.DeepEqual(err, wantErr) {
		t.Fatalf("(callback) Add: error = %#v, want %#v", err, wantErr)
	}
	if _, err := os.Stat(path.Join(d, "pending")); !errors.Is(err, os.ErrNotExist) {
		t.Fatalf("Stat: error = %v", err)
	}

	wantData := []byte{0xde, 0xad, 0xbe, 0xef}
	wantVOD := streamdata.VOD{
		Title:    "\x00",
		Date:     time.Unix(0, 0).UTC(),
		Category: "\t",
	}
	ident := streamdata.Ident{
		Serial:  0xfdfdfdfd,
		Channel: 0xcafe,
		Data: [streamdata.IdentFFLen]byte{
			0xfe, 0xe1, 0xde, 0xad,
			0xfe, 0xed,
			0x0b, 0xad,
			0xf0, 0x0d,
			0, 0, 0, 0, 0, 0,
		},
	}
	if err := c.Add(&ident, func(v *streamdata.VOD, w io.Writer) error {
		*v = wantVOD
		_, err := w.Write(wantData)
		return err
	}); err != nil {
		t.Fatalf("Add: error = %v", err)
	}

	if dents, err := os.ReadDir(path.Join(d, "vod")); err != nil {
		t.Fatal(err)
	} else if len(dents) != 2 {
		t.Fatalf("ReadDir: %#v", dents)
	}

	const wantIdent = "4261281277-51966-fee1dead-feed-0bad-f00d-000000000000"
	var got streamdata.VOD
	if r, err := os.Open(path.Join(d, "vod", wantIdent)); err != nil {
		t.Fatal(err)
	} else if err = json.NewDecoder(r).Decode(&got); err != nil {
		_ = r.Close()
		t.Fatalf("Decode: error = %v", err)
	} else if got != wantVOD {
		t.Errorf("Add: %#v, want %#v", got, wantVOD)
	}

	var iterErr error
	idents := slices.Collect(c.All(&iterErr, false))
	if iterErr != nil {
		t.Fatalf("All: error = %#v", iterErr)
	}
	if len(idents) != 1 || idents[0].String() != wantIdent {
		t.Errorf("All: %#v", idents)
	}

	if gotVOD, err := c.Load(&ident); err != nil {
		t.Fatalf("Load: error = %v", err)
	} else if *gotVOD != wantVOD {
		t.Errorf("Load: %#v, want %#v", *gotVOD, wantVOD)
	}

	if gotData, err := os.ReadFile(path.Join(d, "vod", wantIdent+streamdata.ChannelVODSuffix)); err != nil {
		t.Fatal(err)
	} else if string(gotData) != string(wantData) {
		t.Errorf("Add: data = %#v, want %#v", gotData, wantData)
	}

	if fi, err := os.Stat(path.Join(d, "vod", wantIdent)); err != nil {
		t.Fatal(err)
	} else if fi.Mode().Perm() != 0444 {
		t.Errorf("Perm: %#o", fi.Mode().Perm())
	}
	if fi, err := os.Stat(path.Join(d, "vod", wantIdent+streamdata.ChannelVODSuffix)); err != nil {
		t.Fatal(err)
	} else if fi.Mode().Perm() != 0444 {
		t.Errorf("Perm: %#o", fi.Mode().Perm())
	}

	rf := streamdata.RenameFrom(path.Join(d, "alternate"))
	if err := os.WriteFile(string(rf), []byte{0}, 0); err != nil {
		t.Fatal(err)
	}
	if err := c.Add(&streamdata.Ident{Channel: 0xcafe}, func(*streamdata.VOD, io.Writer) error {
		return rf
	}); err != nil {
		t.Fatalf("Add: error = %v", err)
	}
	if _, err := os.Stat(string(rf)); !errors.Is(err, os.ErrNotExist) {
		t.Fatalf("Stat: error = %v", err)
	}
	if data, err := os.ReadFile(path.Join(
		d,
		"vod",
		(&streamdata.Ident{Channel: 0xcafe}).String()+".mp4",
	)); err != nil {
		t.Fatal(err)
	} else if string(data) != "\x00" {
		t.Errorf("(rf) Add: %#v", data)
	}

	wantVODEdit := streamdata.VOD{
		Title:    "edit\x00",
		Date:     time.Unix(0xdeadbeef, 0).UTC(),
		Category: "\t\x00",
		Mirror:   "https://satori.hifuu.internal/edit.mp4\x00",
	}
	if err := c.Edit(&streamdata.Ident{Channel: 0xcafe}, func(v *streamdata.VOD) error {
		if *v != (streamdata.VOD{}) {
			t.Errorf("Edit: v = %#v", v)
		}

		*v = wantVODEdit
		return nil
	}); err != nil {
		t.Fatalf("Edit: error = %v", err)
	}
	if gotVODEdit, err := c.Load(&streamdata.Ident{Channel: 0xcafe}); err != nil {
		t.Fatalf("(edit) Load: error = %v", err)
	} else if *gotVODEdit != wantVODEdit {
		t.Errorf("Edit: %#v, want %#v", *gotVODEdit, wantVODEdit)
	}

	if err := os.Chmod(path.Join(d, "vod", wantIdent), 0); err != nil {
		t.Fatal(err)
	}
	wantErr = &os.PathError{
		Op:   "openat",
		Path: path.Join("vod", wantIdent),
		Err:  syscall.EACCES,
	}
	if _, err := c.Load(&ident); !reflect.DeepEqual(err, wantErr) {
		t.Fatalf("(perm) Load: error = %#v, want %#v", err, wantErr)
	}

	if err := os.Chmod(path.Join(d, "vod", wantIdent), 0600); err != nil {
		t.Fatal(err)
	} else if err = os.WriteFile(path.Join(d, "vod", wantIdent), nil, 0); err != nil {
		t.Fatal(err)
	}
	wantErr = io.EOF
	if _, err := c.Load(&ident); !reflect.DeepEqual(err, wantErr) {
		t.Fatalf("(invalid) Load: error = %#v, want %#v", err, wantErr)
	}
}

func TestErrors(t *testing.T) {
	t.Parallel()

	testCases := []struct {
		name string
		err  error
		want string
	}{
		{"IdentFieldError", streamdata.IdentFieldError(0xcafe),
			"got 51966 field(s) instead of 7"},
		{"IdentFFError", &streamdata.IdentFFError{Got: 0xcafe, Want: 0xbabe},
			"got 51966 bytes for a 47806-byte long free-form field"},
		{"ChannelMismatchError", &streamdata.ChannelMismatchError{Got: 0xcafe, Want: 0xbabe},
			"attempting to add VOD from channel 51966 to channel 47806"},
	}
	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			t.Parallel()

			if got := tc.err.Error(); got != tc.want {
				t.Errorf("Error: %q, want %q", got, tc.want)
			}
		})
	}
}