package daemon

import (
	"os"
	"path/filepath"
	"strings"
	"testing"

	"banger/internal/paths"
)

// Under the opt-in contract the daemon writes its own ssh_config file
// and never touches ~/.ssh/config on its own.
func TestSyncVMSSHClientConfigWritesBangerFileOnly(t *testing.T) {
	homeDir := t.TempDir()
	t.Setenv("HOME", homeDir)

	knownHostsPath := filepath.Join(homeDir, ".local", "state", "banger", "ssh", "known_hosts")
	layout := paths.Layout{
		ConfigDir:      filepath.Join(homeDir, ".config", "banger"),
		KnownHostsPath: knownHostsPath,
	}
	keyPath := filepath.Join(homeDir, ".config", "banger", "ssh", "id_ed25519")

	if err := syncVMSSHClientConfig(layout, keyPath); err != nil {
		t.Fatalf("syncVMSSHClientConfig: %v", err)
	}

	// Banger's own ssh_config file has the `Host *.vm` stanza.
	bangerConfig, err := os.ReadFile(BangerSSHConfigPath(layout))
	if err != nil {
		t.Fatalf("ReadFile(banger ssh_config): %v", err)
	}
	for _, want := range []string{
		"Host *.vm",
		"IdentityFile " + keyPath,
		"UserKnownHostsFile " + knownHostsPath,
		"StrictHostKeyChecking accept-new",
	} {
		if !strings.Contains(string(bangerConfig), want) {
			t.Fatalf("banger ssh_config missing %q:\n%s", want, bangerConfig)
		}
	}

	// ~/.ssh/config must NOT have been created or modified.
	if _, err := os.Stat(filepath.Join(homeDir, ".ssh", "config")); !os.IsNotExist(err) {
		t.Fatalf("~/.ssh/config should be untouched; stat err = %v", err)
	}

	// Regression: the legacy posture (strict no + /dev/null) must not
	// reappear in the banger file.
	for _, must := range []string{
		"StrictHostKeyChecking no",
		"UserKnownHostsFile /dev/null",
	} {
		if strings.Contains(string(bangerConfig), must) {
			t.Fatalf("banger ssh_config leaked legacy posture %q:\n%s", must, bangerConfig)
		}
	}
}

func TestInstallUserSSHIncludeAddsIncludeBlock(t *testing.T) {
	homeDir := t.TempDir()
	t.Setenv("HOME", homeDir)

	layout := paths.Layout{ConfigDir: filepath.Join(homeDir, ".config", "banger")}
	if err := os.MkdirAll(layout.ConfigDir, 0o755); err != nil {
		t.Fatalf("MkdirAll: %v", err)
	}
	// Write a fake banger ssh_config so Install has something to include.
	if err := os.WriteFile(BangerSSHConfigPath(layout), []byte("Host *.vm\n"), 0o644); err != nil {
		t.Fatalf("WriteFile(banger ssh_config): %v", err)
	}

	if err := InstallUserSSHInclude(layout); err != nil {
		t.Fatalf("InstallUserSSHInclude: %v", err)
	}
	got, err := os.ReadFile(filepath.Join(homeDir, ".ssh", "config"))
	if err != nil {
		t.Fatalf("ReadFile(~/.ssh/config): %v", err)
	}
	want := "Include " + BangerSSHConfigPath(layout)
	if !strings.Contains(string(got), want) {
		t.Fatalf("user config missing %q:\n%s", want, got)
	}
	if !strings.Contains(string(got), bangerSSHIncludeBegin) {
		t.Fatalf("user config missing begin marker:\n%s", got)
	}
}

func TestInstallUserSSHIncludeIsIdempotent(t *testing.T) {
	homeDir := t.TempDir()
	t.Setenv("HOME", homeDir)

	layout := paths.Layout{ConfigDir: filepath.Join(homeDir, ".config", "banger")}
	if err := os.MkdirAll(layout.ConfigDir, 0o755); err != nil {
		t.Fatalf("MkdirAll: %v", err)
	}
	if err := os.WriteFile(BangerSSHConfigPath(layout), []byte("Host *.vm\n"), 0o644); err != nil {
		t.Fatalf("WriteFile: %v", err)
	}
	for i := 0; i < 3; i++ {
		if err := InstallUserSSHInclude(layout); err != nil {
			t.Fatalf("InstallUserSSHInclude (%d): %v", i, err)
		}
	}
	got, err := os.ReadFile(filepath.Join(homeDir, ".ssh", "config"))
	if err != nil {
		t.Fatalf("ReadFile: %v", err)
	}
	if n := strings.Count(string(got), bangerSSHIncludeBegin); n != 1 {
		t.Fatalf("begin markers = %d, want 1:\n%s", n, got)
	}
}

func TestInstallUserSSHIncludeMigratesLegacyInlineBlock(t *testing.T) {
	homeDir := t.TempDir()
	t.Setenv("HOME", homeDir)

	layout := paths.Layout{ConfigDir: filepath.Join(homeDir, ".config", "banger")}
	if err := os.MkdirAll(layout.ConfigDir, 0o755); err != nil {
		t.Fatalf("MkdirAll: %v", err)
	}
	if err := os.WriteFile(BangerSSHConfigPath(layout), []byte("Host *.vm\n"), 0o644); err != nil {
		t.Fatalf("WriteFile: %v", err)
	}

	sshDir := filepath.Join(homeDir, ".ssh")
	if err := os.MkdirAll(sshDir, 0o700); err != nil {
		t.Fatalf("MkdirAll(.ssh): %v", err)
	}
	legacy := strings.Join([]string{
		"ServerAliveInterval 120",
		"",
		vmSSHConfigIncludeBegin,
		"Host *.vm",
		"    User root",
		"    IdentityFile /some/old/key",
		vmSSHConfigIncludeEnd,
		"",
		"Host other",
		"    HostName 192.0.2.5",
		"",
	}, "\n")
	if err := os.WriteFile(filepath.Join(sshDir, "config"), []byte(legacy), 0o600); err != nil {
		t.Fatalf("seed legacy config: %v", err)
	}

	if err := InstallUserSSHInclude(layout); err != nil {
		t.Fatalf("InstallUserSSHInclude: %v", err)
	}
	got, err := os.ReadFile(filepath.Join(sshDir, "config"))
	if err != nil {
		t.Fatalf("ReadFile: %v", err)
	}
	gotStr := string(got)
	// Legacy inline block must be gone.
	if strings.Contains(gotStr, vmSSHConfigIncludeBegin) {
		t.Fatalf("legacy inline block survived:\n%s", gotStr)
	}
	// New Include block must be present.
	if !strings.Contains(gotStr, bangerSSHIncludeBegin) {
		t.Fatalf("new include block missing:\n%s", gotStr)
	}
	// Unrelated stanzas must be preserved.
	for _, want := range []string{"ServerAliveInterval 120", "Host other"} {
		if !strings.Contains(gotStr, want) {
			t.Fatalf("user config lost unrelated entry %q:\n%s", want, gotStr)
		}
	}
}

func TestUninstallUserSSHIncludeRemovesBothMarkerBlocks(t *testing.T) {
	homeDir := t.TempDir()
	t.Setenv("HOME", homeDir)

	sshDir := filepath.Join(homeDir, ".ssh")
	if err := os.MkdirAll(sshDir, 0o700); err != nil {
		t.Fatalf("MkdirAll: %v", err)
	}
	seed := strings.Join([]string{
		"Host keep",
		"    HostName 198.51.100.1",
		"",
		vmSSHConfigIncludeBegin,
		"Host *.vm",
		vmSSHConfigIncludeEnd,
		"",
		bangerSSHIncludeBegin,
		"Include /tmp/banger-ssh-config",
		bangerSSHIncludeEnd,
		"",
	}, "\n")
	if err := os.WriteFile(filepath.Join(sshDir, "config"), []byte(seed), 0o600); err != nil {
		t.Fatalf("seed: %v", err)
	}

	if err := UninstallUserSSHInclude(); err != nil {
		t.Fatalf("UninstallUserSSHInclude: %v", err)
	}
	got, err := os.ReadFile(filepath.Join(sshDir, "config"))
	if err != nil {
		t.Fatalf("ReadFile: %v", err)
	}
	gotStr := string(got)
	for _, banned := range []string{vmSSHConfigIncludeBegin, bangerSSHIncludeBegin} {
		if strings.Contains(gotStr, banned) {
			t.Fatalf("residue of %q:\n%s", banned, gotStr)
		}
	}
	if !strings.Contains(gotStr, "Host keep") {
		t.Fatalf("lost unrelated entry:\n%s", gotStr)
	}
}

func TestUninstallUserSSHIncludeIsNoOpWhenMissing(t *testing.T) {
	homeDir := t.TempDir()
	t.Setenv("HOME", homeDir)
	if err := UninstallUserSSHInclude(); err != nil {
		t.Fatalf("UninstallUserSSHInclude on missing file: %v", err)
	}
	// Still no ~/.ssh/config.
	if _, err := os.Stat(filepath.Join(homeDir, ".ssh", "config")); !os.IsNotExist(err) {
		t.Fatalf("~/.ssh/config unexpectedly created; stat err = %v", err)
	}
}

func TestUserSSHIncludeInstalledDetectsBothMarkers(t *testing.T) {
	for _, tc := range []struct {
		name   string
		seed   string
		wantIn bool
	}{
		{"missing file", "", false},
		{"unrelated only", "Host other\n    HostName 1.2.3.4\n", false},
		{"legacy marker", vmSSHConfigIncludeBegin + "\nHost *.vm\n" + vmSSHConfigIncludeEnd + "\n", true},
		{"new marker", bangerSSHIncludeBegin + "\nInclude /tmp/banger\n" + bangerSSHIncludeEnd + "\n", true},
	} {
		t.Run(tc.name, func(t *testing.T) {
			homeDir := t.TempDir()
			t.Setenv("HOME", homeDir)
			if tc.seed != "" {
				if err := os.MkdirAll(filepath.Join(homeDir, ".ssh"), 0o700); err != nil {
					t.Fatalf("MkdirAll: %v", err)
				}
				if err := os.WriteFile(filepath.Join(homeDir, ".ssh", "config"), []byte(tc.seed), 0o600); err != nil {
					t.Fatalf("WriteFile: %v", err)
				}
			}
			got, err := UserSSHIncludeInstalled()
			if err != nil {
				t.Fatalf("UserSSHIncludeInstalled: %v", err)
			}
			if got != tc.wantIn {
				t.Fatalf("got %v, want %v", got, tc.wantIn)
			}
		})
	}
}