package uploads_test

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

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	"git.d-ma.be/mathias/tapir/internal/domain"
	"git.d-ma.be/mathias/tapir/internal/uploads"
)

type fakeStore struct {
	created  []string // titles
	hadVideo []bool
	failed   map[string]domain.UploadErrorKind
	nextID   string
}

func (f *fakeStore) CreateUpload(_ context.Context, _, title string, hadVideo bool) (string, error) {
	f.created = append(f.created, title)
	f.hadVideo = append(f.hadVideo, hadVideo)
	return f.nextID, nil
}

func (f *fakeStore) FailUpload(_ context.Context, _, id string, kind domain.UploadErrorKind) error {
	if f.failed == nil {
		f.failed = map[string]domain.UploadErrorKind{}
	}
	f.failed[id] = kind
	return nil
}

type fakeProber struct {
	probe uploads.Probe
	err   error
	paths []string
	seen  []byte // content of the file at probe time
}

func (f *fakeProber) Probe(_ context.Context, path string) (uploads.Probe, error) {
	f.paths = append(f.paths, path)
	f.seen, _ = os.ReadFile(path)
	return f.probe, f.err
}

type fakeSubmitter struct {
	jobs []uploads.Job
	err  error
}

func (f *fakeSubmitter) Submit(j uploads.Job) error {
	f.jobs = append(f.jobs, j)
	return f.err
}

type rig struct {
	in  *uploads.Intake
	st  *fakeStore
	pr  *fakeProber
	sub *fakeSubmitter
	tmp string
}

func newRig(t *testing.T) *rig {
	t.Helper()
	r := &rig{
		st:  &fakeStore{nextID: "up-1"},
		pr:  &fakeProber{probe: uploads.Probe{Duration: 10 * time.Minute, HasAudio: true}},
		sub: &fakeSubmitter{},
		tmp: t.TempDir(),
	}
	r.in = uploads.NewIntake(r.st, r.pr, r.sub, uploads.Limits{MaxBytes: 1024, MaxDuration: 90 * time.Minute}, r.tmp)
	return r
}

func (r *rig) tmpFiles(t *testing.T) []string {
	t.Helper()
	ents, err := os.ReadDir(r.tmp)
	require.NoError(t, err)
	var names []string
	for _, e := range ents {
		names = append(names, e.Name())
	}
	return names
}

func TestAccept_ValidAudioIsStoredProbedQueuedAndSubmitted(t *testing.T) {
	r := newRig(t)
	audio := bytes.Repeat([]byte("a"), 500)

	id, err := r.in.Accept(context.Background(), "user-1", "Teams export", bytes.NewReader(audio))

	require.NoError(t, err)
	assert.Equal(t, "up-1", id)
	assert.Equal(t, []string{"Teams export"}, r.st.created)
	assert.Equal(t, audio, r.pr.seen, "the prober must see the complete uploaded bytes, on disk")
	require.Len(t, r.sub.jobs, 1)
	job := r.sub.jobs[0]
	assert.Equal(t, uploads.Job{UserID: "user-1", UploadID: "up-1", Path: job.Path}, job)
	assert.Equal(t, filepath.Dir(job.Path), r.tmp, "the temp file lives in the configured directory")
	got, err := os.ReadFile(job.Path)
	require.NoError(t, err)
	assert.Equal(t, audio, got, "the handed-over file still exists: the worker, not Accept, deletes it")
}

func TestAccept_OversizeBodyIsRejectedAndLeavesNothingBehind(t *testing.T) {
	r := newRig(t)

	_, err := r.in.Accept(context.Background(), "user-1", "big", strings.NewReader(strings.Repeat("a", 1025)))

	var rej *uploads.RejectError
	require.True(t, errors.As(err, &rej))
	assert.Equal(t, uploads.ReasonTooLarge, rej.Reason)
	assert.Contains(t, rej.Message, "limit")
	assert.Empty(t, r.pr.paths, "a file already over the size cap must not be probed")
	assert.Empty(t, r.st.created, "a rejected upload creates no row")
	assert.Empty(t, r.sub.jobs)
	assert.Empty(t, r.tmpFiles(t), "the partial temp file must be removed")
}

func TestAccept_BodyExactlyAtTheLimitIsAccepted(t *testing.T) {
	r := newRig(t)

	_, err := r.in.Accept(context.Background(), "user-1", "edge", strings.NewReader(strings.Repeat("a", 1024)))

	require.NoError(t, err)
}

func TestAccept_ProbeVerdictRejectsWithoutRowAndRemovesTheFile(t *testing.T) {
	tests := []struct {
		name   string
		probe  uploads.Probe
		reason uploads.Reason
	}{
		{"video with no audio", uploads.Probe{Duration: time.Minute, HasVideo: true}, uploads.ReasonNoAudio},
		{"too long", uploads.Probe{Duration: 2 * time.Hour, HasAudio: true}, uploads.ReasonTooLong},
		{"no audio", uploads.Probe{Duration: time.Minute}, uploads.ReasonNoAudio},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			r := newRig(t)
			r.pr.probe = tt.probe

			_, err := r.in.Accept(context.Background(), "user-1", "t", strings.NewReader("data"))

			var rej *uploads.RejectError
			require.True(t, errors.As(err, &rej))
			assert.Equal(t, tt.reason, rej.Reason)
			assert.Empty(t, r.st.created)
			assert.Empty(t, r.sub.jobs)
			assert.Empty(t, r.tmpFiles(t))
		})
	}
}

func TestAccept_UnreadableFileIsARejectionButAProberFaultIsAnError(t *testing.T) {
	t.Run("ffprobe says the file is not media", func(t *testing.T) {
		r := newRig(t)
		r.pr.err = uploads.ErrUnreadable

		_, err := r.in.Accept(context.Background(), "user-1", "t", strings.NewReader("not media"))

		var rej *uploads.RejectError
		require.True(t, errors.As(err, &rej), "the user's file is the problem: tell them")
		assert.Equal(t, uploads.ReasonUnreadable, rej.Reason)
		assert.Empty(t, r.tmpFiles(t))
	})
	t.Run("the prober itself broke", func(t *testing.T) {
		r := newRig(t)
		r.pr.err = errors.New("exec: ffprobe: executable file not found")

		_, err := r.in.Accept(context.Background(), "user-1", "t", strings.NewReader("data"))

		require.Error(t, err)
		var rej *uploads.RejectError
		assert.False(t, errors.As(err, &rej), "our fault must not be reported as the user's bad file")
		assert.Empty(t, r.st.created)
		assert.Empty(t, r.tmpFiles(t))
	})
}

func TestAccept_ClientDisconnectMidUploadLeavesNothingBehind(t *testing.T) {
	r := newRig(t)
	body := io.MultiReader(strings.NewReader("partial"), iotest.ErrReader(errors.New("client went away")))

	_, err := r.in.Accept(context.Background(), "user-1", "t", body)

	require.Error(t, err)
	assert.Empty(t, r.pr.paths)
	assert.Empty(t, r.st.created)
	assert.Empty(t, r.tmpFiles(t))
}

func TestAccept_SubmitFailureFailsTheRowHonestlyAndRemovesTheFile(t *testing.T) {
	r := newRig(t)
	r.sub.err = errors.New("worker stopped")

	_, err := r.in.Accept(context.Background(), "user-1", "t", strings.NewReader("data"))

	require.Error(t, err)
	assert.Equal(t, domain.UploadErrInterrupted, r.st.failed["up-1"],
		"a row that will never run must not sit queued: that is the stuck spinner ADR-025 forbids")
	assert.Empty(t, r.tmpFiles(t))
}

func TestAccept_AFileWithAVideoTrackIsAcceptedAndRecordsThatItHadOne(t *testing.T) {
	tests := []struct {
		name      string
		probe     uploads.Probe
		wantVideo bool
	}{
		{"audio only", uploads.Probe{Duration: 10 * time.Minute, HasAudio: true}, false},
		{"audio with a video track (a Teams meeting with the camera off)", uploads.Probe{Duration: 10 * time.Minute, HasAudio: true, HasVideo: true}, true},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			r := newRig(t)
			r.pr.probe = tt.probe

			id, err := r.in.Accept(context.Background(), "user-1", "t", strings.NewReader("data"))

			require.NoError(t, err)
			assert.Equal(t, "up-1", id)
			assert.Equal(t, []bool{tt.wantVideo}, r.st.hadVideo,
				"the row must say whether a video track was present, so the page can say it was ignored")
			assert.Len(t, r.sub.jobs, 1, "it is queued like any other recording")
		})
	}
}