package api

import (
	"encoding/json"
	"io"
	"log/slog"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"testing"
)

// withClientAPKDir points the handlers at a fresh temp dir for each
// test and restores the env var on cleanup. Returns the dir.
func withClientAPKDir(t *testing.T) string {
	t.Helper()
	dir := t.TempDir()
	prev, hadPrev := os.LookupEnv("MINSTREL_CLIENT_APK_DIR")
	os.Setenv("MINSTREL_CLIENT_APK_DIR", dir)
	t.Cleanup(func() {
		if hadPrev {
			os.Setenv("MINSTREL_CLIENT_APK_DIR", prev)
		} else {
			os.Unsetenv("MINSTREL_CLIENT_APK_DIR")
		}
	})
	return dir
}

func TestClientVersion_404WhenNoAPK(t *testing.T) {
	withClientAPKDir(t)
	h := &handlers{logger: slog.New(slog.NewTextHandler(io.Discard, nil))}
	rr := httptest.NewRecorder()
	h.handleClientVersion(rr, httptest.NewRequest(http.MethodGet, "/api/client/version", nil))
	if rr.Code != http.StatusNotFound {
		t.Errorf("want 404, got %d", rr.Code)
	}
}

func TestClientVersion_404WhenAPKButNoVersion(t *testing.T) {
	dir := withClientAPKDir(t)
	if err := os.WriteFile(filepath.Join(dir, clientAPKFilename), []byte("fake apk"), 0o644); err != nil {
		t.Fatal(err)
	}
	h := &handlers{logger: slog.New(slog.NewTextHandler(io.Discard, nil))}
	rr := httptest.NewRecorder()
	h.handleClientVersion(rr, httptest.NewRequest(http.MethodGet, "/api/client/version", nil))
	if rr.Code != http.StatusNotFound {
		t.Errorf("want 404, got %d", rr.Code)
	}
}

func TestClientVersion_200WithBothFiles(t *testing.T) {
	dir := withClientAPKDir(t)
	body := []byte("fake apk content")
	if err := os.WriteFile(filepath.Join(dir, clientAPKFilename), body, 0o644); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(dir, clientVersionFile), []byte("v2026.05.10\n"), 0o644); err != nil {
		t.Fatal(err)
	}
	h := &handlers{logger: slog.New(slog.NewTextHandler(io.Discard, nil))}
	rr := httptest.NewRecorder()
	h.handleClientVersion(rr, httptest.NewRequest(http.MethodGet, "/api/client/version", nil))
	if rr.Code != http.StatusOK {
		t.Fatalf("want 200, got %d (body: %s)", rr.Code, rr.Body.String())
	}
	var resp clientVersionResponse
	if err := json.Unmarshal(rr.Body.Bytes(), &resp); err != nil {
		t.Fatal(err)
	}
	if resp.Version != "v2026.05.10" {
		t.Errorf("version: want trimmed v2026.05.10, got %q", resp.Version)
	}
	if resp.APKURL != "/api/client/apk" {
		t.Errorf("apk_url: want /api/client/apk, got %q", resp.APKURL)
	}
	if resp.SizeBytes != int64(len(body)) {
		t.Errorf("size_bytes: want %d, got %d", len(body), resp.SizeBytes)
	}
}

func TestClientAPK_404WhenMissing(t *testing.T) {
	withClientAPKDir(t)
	h := &handlers{logger: slog.New(slog.NewTextHandler(io.Discard, nil))}
	rr := httptest.NewRecorder()
	h.handleClientAPK(rr, httptest.NewRequest(http.MethodGet, "/api/client/apk", nil))
	if rr.Code != http.StatusNotFound {
		t.Errorf("want 404, got %d", rr.Code)
	}
}

func TestClientAPK_StreamsWithCorrectContentType(t *testing.T) {
	dir := withClientAPKDir(t)
	body := []byte("PK\x03\x04 fake apk bytes")
	if err := os.WriteFile(filepath.Join(dir, clientAPKFilename), body, 0o644); err != nil {
		t.Fatal(err)
	}
	h := &handlers{logger: slog.New(slog.NewTextHandler(io.Discard, nil))}
	rr := httptest.NewRecorder()
	h.handleClientAPK(rr, httptest.NewRequest(http.MethodGet, "/api/client/apk", nil))
	if rr.Code != http.StatusOK {
		t.Fatalf("want 200, got %d", rr.Code)
	}
	if got := rr.Header().Get("Content-Type"); got != "application/vnd.android.package-archive" {
		t.Errorf("Content-Type: want application/vnd.android.package-archive, got %q", got)
	}
	if rr.Body.Len() != len(body) {
		t.Errorf("body length: want %d, got %d", len(body), rr.Body.Len())
	}
	if got := rr.Body.Bytes(); string(got) != string(body) {
		t.Errorf("body bytes mismatch")
	}
}