package main

import (
	"crypto/ed25519"
	"crypto/rand"
	"encoding/base64"
	"encoding/json"
	"io"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"gitgud.io/mike/mpv-manager/pkg/releasemanifest"
	"github.com/stretchr/testify/require"
)

func TestPublisherChannelIsolationAndRollback(t *testing.T) {
	root := t.TempDir()
	legacy := []byte(`{"version":"1.2.0","manager":{"linux-amd64":{"URL":"https://example.test/old"}}}`)
	require.NoError(t, os.WriteFile(filepath.Join(root, "releases.json"), legacy, 0644))
	pub, key, err := ed25519.GenerateKey(rand.Reader)
	require.NoError(t, err)
	t.Setenv("MANIFEST_PUBLIC_KEYS", "publisher="+base64.StdEncoding.EncodeToString(pub))
	published := time.Now().UTC().Add(-time.Hour)
	write := func(channel, ver string, at time.Time) (string, []byte) {
		t.Helper()
		m := releasemanifest.Manifest{SchemaVersion: 2, Channel: channel, Version: ver, MinimumUpdaterVersion: "1.2.0", PublishedAt: at.Format(time.RFC3339), MpvVersion: "0.41.0"}
		assets := []releasemanifest.Asset{}
		entries := []struct {
			os, arch string
			entry    *struct{ URL, BLAKE3 string }
		}{
			{"linux", "amd64", &m.Manager.LinuxAMD64}, {"linux", "arm64", &m.Manager.LinuxARM64},
			{"windows", "amd64", &m.Manager.WinX86_64}, {"windows", "arm64", &m.Manager.WinARM64},
			{"darwin", "amd64", &m.Manager.MacosIntel}, {"darwin", "arm64", &m.Manager.MacosARM},
		}
		for _, e := range entries {
			e.entry.URL = "https://example.test/" + ver + "/" + e.os + "-" + e.arch
			e.entry.BLAKE3 = "blake3:" + strings.Repeat("a", 64)
			baseline := "arm64"
			if e.arch == "amd64" {
				baseline = "x86-64-v2"
			}
			assets = append(assets, releasemanifest.Asset{GOOS: e.os, GOARCH: e.arch, CPUBaseline: baseline, URL: e.entry.URL, BLAKE3: e.entry.BLAKE3, Size: 10, Format: "raw", InstallScope: "portable", UpdateStrategy: "external-helper", ExpectedProduct: "mpv-manager", ExpectedComponent: "manager-portable"})
		}
		m.Components = map[string]releasemanifest.Component{"manager-portable": {Version: ver, Assets: assets}}
		require.NoError(t, m.Sign("publisher", key))
		data, err := json.Marshal(m)
		require.NoError(t, err)
		path := filepath.Join(t.TempDir(), "candidate.json")
		require.NoError(t, os.WriteFile(path, data, 0600))
		return path, data
	}
	publish := func(path, channel string) error {
		return run([]string{"-manifest", path, "-api-dir", root, "-channel", channel}, io.Discard)
	}
	rc, rcBytes := write("rc", "1.3.0-rc.2", published)
	require.NoError(t, publish(rc, "rc"))
	got, err := os.ReadFile(filepath.Join(root, "releases.json"))
	require.NoError(t, err)
	require.Equal(t, legacy, got)
	require.NoFileExists(t, filepath.Join(root, "releases", "stable.json"))
	require.ErrorContains(t, publish(rc, "stable"), "authorized destination")
	require.NoError(t, publish(rc, "rc")) // retry is idempotent
	older, _ := write("rc", "1.3.0-rc.1", published.Add(time.Minute))
	require.ErrorContains(t, publish(older, "rc"), "rollback")
	equivocation, _ := write("rc", "1.3.0-rc.3", published)
	require.ErrorContains(t, publish(equivocation, "rc"), "equivocation")
	stable, stableBytes := write("stable", "1.3.0", published.Add(time.Minute))
	require.NoError(t, publish(stable, "stable"))
	for _, name := range []string{"releases.json", "releases/stable.json"} {
		got, err = os.ReadFile(filepath.Join(root, name))
		require.NoError(t, err)
		require.Equal(t, stableBytes, got)
	}
	got, err = os.ReadFile(filepath.Join(root, "releases/rc.json"))
	require.NoError(t, err)
	require.Equal(t, rcBytes, got)
	// Legacy readers retain the exact spelling/shape they used before v1.3.
	var oldClient struct {
		Version    string
		MpvVersion string
		Manager    struct {
			Linux struct{ URL, BLAKE3 string } `json:"linux-amd64"`
		}
	}
	require.NoError(t, json.Unmarshal(stableBytes, &oldClient))
	require.Equal(t, "1.3.0", oldClient.Version)
	require.Equal(t, "0.41.0", oldClient.MpvVersion)
	require.Contains(t, oldClient.Manager.Linux.URL, "1.3.0")
	tampered := strings.ReplaceAll(string(stableBytes), "0.41.0", "0.99.0")
	require.NoError(t, os.WriteFile(stable, []byte(tampered), 0600))
	require.ErrorContains(t, publish(stable, "stable"), "signature")
	// Rejected publication cannot change the served feed.
	got, err = os.ReadFile(filepath.Join(root, "releases/stable.json"))
	require.NoError(t, err)
	require.Equal(t, stableBytes, got)
}