package export

import (
	"archive/zip"
	"bytes"
	"compress/gzip"
	"errors"
	"io"
	"os"
	"path/filepath"
	"sort"
	"strings"
	"testing"

	"git.monoexp.com/bajdev/mpckit/internal/project"
)

const testdata = "../../testdata"

func must(t *testing.T, err error) {
	t.Helper()
	if err != nil {
		t.Fatal(err)
	}
}

func gunzip(t *testing.T, b []byte) []byte {
	t.Helper()
	zr, err := gzip.NewReader(bytes.NewReader(b))
	must(t, err)
	out, err := io.ReadAll(zr)
	must(t, err)
	return out
}

func readFile(t *testing.T, path string) []byte {
	t.Helper()
	b, err := os.ReadFile(path)
	must(t, err)
	return b
}

// buildT1 makes MpckitT1 through the model (as in the M2 golden test).
func buildT1(t *testing.T) *project.Project {
	t.Helper()
	p, err := project.New("MpckitT1")
	must(t, err)
	dir := filepath.Join(testdata, "accepted", "MpckitT1"+project.DataSuffix)
	must(t, p.AssignSample(0, filepath.Join(dir, "Linn 9000 kick.wav")))
	must(t, p.AssignSample(16, filepath.Join(dir, "Linn 9000 kick001.wav")))
	must(t, p.SetTune(16, 5, 0))
	must(t, p.SetSequence(0, "Verse", 96, 8))
	must(t, p.AddSequence(1))
	must(t, p.SetSequence(1, "Chorus", 96, 4))
	return p
}

func listDir(t *testing.T, dir string) []string {
	t.Helper()
	ents, err := os.ReadDir(dir)
	must(t, err)
	var names []string
	for _, e := range ents {
		names = append(names, e.Name())
	}
	sort.Strings(names)
	return names
}

func TestFolder(t *testing.T) {
	dest := t.TempDir()
	p := buildT1(t)
	path, err := Folder(p, dest, false)
	must(t, err)
	if path != filepath.Join(dest, "MpckitT1.xpj") {
		t.Errorf("path = %s", path)
	}
	if got := listDir(t, dest); strings.Join(got, "|") != "MpckitT1.xpj|MpckitT1_[ProjectData]" {
		t.Errorf("dest holds %v", got)
	}
	want := gunzip(t, readFile(t, filepath.Join(testdata, "accepted", "MpckitT1.xpj")))
	if !bytes.Equal(gunzip(t, readFile(t, path)), want) {
		t.Error("exported .xpj differs from MpckitT1.xpj")
	}
	src := filepath.Join(testdata, "accepted", "MpckitT1"+project.DataSuffix)
	data := filepath.Join(dest, "MpckitT1"+project.DataSuffix)
	if got := listDir(t, data); strings.Join(got, "|") != "Linn 9000 kick.wav|Linn 9000 kick001.wav" {
		t.Errorf("data folder holds %v", got)
	}
	for _, f := range listDir(t, data) {
		if !bytes.Equal(readFile(t, filepath.Join(data, f)), readFile(t, filepath.Join(src, f))) {
			t.Errorf("%s differs from its source", f)
		}
	}

	// Again without overwrite: refused, nothing touched.
	marker := filepath.Join(data, "keep.txt")
	must(t, os.WriteFile(marker, []byte("x"), 0o644))
	_, err = Folder(p, dest, false)
	var exists *ExistsError
	if !errors.As(err, &exists) || len(exists.Paths) != 2 {
		t.Fatalf("second export: %v", err)
	}
	if _, err := os.Stat(marker); err != nil {
		t.Error("refused export changed the folder")
	}
	// With overwrite: the old data folder is replaced, not merged.
	_, err = Folder(p, dest, true)
	must(t, err)
	if _, err := os.Stat(marker); err == nil {
		t.Error("overwrite kept a stale file in the data folder")
	}
	if got := listDir(t, dest); len(got) != 2 {
		t.Errorf("temporary files left behind: %v", got)
	}
}

func TestFolderEmptyProject(t *testing.T) {
	dest := t.TempDir()
	p, err := project.New("Empty")
	must(t, err)
	_, err = Folder(p, dest, false)
	must(t, err)
	// The device creates the data folder even with no samples; so do we.
	if got := listDir(t, filepath.Join(dest, "Empty"+project.DataSuffix)); len(got) != 0 {
		t.Errorf("data folder holds %v", got)
	}
}

func TestRenamedLoadedProject(t *testing.T) {
	p, _, err := project.Load(filepath.Join(testdata, "device", "DemoFile.xpj"))
	must(t, err)
	must(t, p.SetName("Renamed"))
	dest := t.TempDir()
	_, err = Folder(p, dest, false)
	must(t, err)
	got := listDir(t, filepath.Join(dest, "Renamed"+project.DataSuffix))
	if len(got) != 6 {
		t.Errorf("data folder holds %v", got)
	}
	want := gunzip(t, readFile(t, filepath.Join(testdata, "device", "DemoFile.xpj")))
	if !bytes.Equal(gunzip(t, readFile(t, filepath.Join(dest, "Renamed.xpj"))), want) {
		t.Error("renaming changed the file contents")
	}
}

func TestMissingSources(t *testing.T) {
	tmp := t.TempDir()
	p, err := project.New("Missing")
	must(t, err)
	for i, name := range []string{"a.wav", "b.wav", "c.wav"} {
		src := filepath.Join(tmp, name)
		must(t, os.WriteFile(src, readFile(t, filepath.Join(testdata, "accepted", "MpckitT2"+project.DataSuffix, "Linn 9000 kick.wav")), 0o644))
		must(t, p.AssignSample(i, src))
	}
	must(t, os.Remove(filepath.Join(tmp, "a.wav")))
	must(t, os.Remove(filepath.Join(tmp, "c.wav")))

	dest := t.TempDir()
	_, err = Folder(p, dest, false)
	var missing *MissingError
	if !errors.As(err, &missing) || strings.Join(missing.Files, ",") != "a.wav,c.wav" {
		t.Fatalf("Folder: %v", err)
	}
	if !strings.Contains(err.Error(), "2 sample file(s)") {
		t.Errorf("message: %v", err)
	}
	if err := Zip(p, filepath.Join(dest, "m.zip"), false); !errors.As(err, &missing) {
		t.Fatalf("Zip: %v", err)
	}
	if got := listDir(t, dest); len(got) != 0 {
		t.Errorf("failed export wrote %v", got)
	}
}

func TestZip(t *testing.T) {
	dest := t.TempDir()
	zpath := filepath.Join(dest, "kit.zip")
	p := buildT1(t)
	must(t, Zip(p, zpath, false))

	zr, err := zip.OpenReader(zpath)
	must(t, err)
	defer zr.Close()
	var names []string
	files := map[string][]byte{}
	for _, f := range zr.File {
		names = append(names, f.Name)
		rc, err := f.Open()
		must(t, err)
		b, err := io.ReadAll(rc)
		rc.Close()
		must(t, err)
		files[f.Name] = b
	}
	want := "MpckitT1.xpj|MpckitT1_[ProjectData]/|MpckitT1_[ProjectData]/Linn 9000 kick.wav|MpckitT1_[ProjectData]/Linn 9000 kick001.wav"
	if strings.Join(names, "|") != want {
		t.Errorf("entries %v", names)
	}
	if !bytes.Equal(gunzip(t, files["MpckitT1.xpj"]), gunzip(t, readFile(t, filepath.Join(testdata, "accepted", "MpckitT1.xpj")))) {
		t.Error("zipped .xpj differs from MpckitT1.xpj")
	}
	src := filepath.Join(testdata, "accepted", "MpckitT1"+project.DataSuffix, "Linn 9000 kick001.wav")
	if !bytes.Equal(files["MpckitT1_[ProjectData]/Linn 9000 kick001.wav"], readFile(t, src)) {
		t.Error("zipped WAV differs from its source")
	}

	var exists *ExistsError
	if err := Zip(p, zpath, false); !errors.As(err, &exists) {
		t.Errorf("existing zip: %v", err)
	}
	must(t, Zip(p, zpath, true))
	if got := listDir(t, dest); strings.Join(got, "|") != "kit.zip" {
		t.Errorf("temporary files left behind: %v", got)
	}
}