//go:build linux

package installer

import (
	"bytes"
	"errors"
	"fmt"
	"io"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
)

func Install(opts InstallOptions) error {
	if opts.Listen == "" {
		opts.Listen = "127.0.0.1:8765"
	}

	home, err := os.UserHomeDir()
	if err != nil {
		return err
	}
	installDir := filepath.Join(home, ".local", "share", ServiceName)
	binPath := filepath.Join(installDir, ServiceName)
	configDir := filepath.Join(home, ".config", ServiceName)
	envFile := filepath.Join(configDir, ServiceName+".env")
	unitDir := filepath.Join(home, ".config", "systemd", "user")
	unitFile := filepath.Join(unitDir, ServiceName+".service")

	allowArgs := buildLinuxAllowArgs(opts.Allow)

	if opts.DryRun {
		return nil
	}

	if err := os.MkdirAll(installDir, 0o755); err != nil {
		return err
	}
	if err := os.MkdirAll(configDir, 0o755); err != nil {
		return err
	}
	if err := os.MkdirAll(unitDir, 0o755); err != nil {
		return err
	}

	exePath, err := os.Executable()
	if err != nil {
		return err
	}
	if err := copySelfAtomic(exePath, binPath, 0o755); err != nil {
		return err
	}

	env := fmt.Sprintf("# %s environment\nLISTEN=\"%s\"\nALLOW_ARGS=\"%s\"\n", ServiceName, escapeDoubleQuotes(opts.Listen), escapeDoubleQuotes(allowArgs))
	if err := os.WriteFile(envFile, []byte(env), 0o600); err != nil {
		return err
	}

	unit := `[Unit]
Description=luxtools-client (local folder opener helper)
After=graphical-session.target
PartOf=graphical-session.target

[Service]
Type=simple
EnvironmentFile=%h/.config/luxtools-client/luxtools-client.env
Environment=DBUS_SESSION_BUS_ADDRESS=unix:path=%t/bus
ExecStart=/bin/sh -lc '%h/.local/share/luxtools-client/luxtools-client -listen "$LISTEN" $ALLOW_ARGS'
Restart=on-failure
RestartSec=1

NoNewPrivileges=true
PrivateTmp=true

[Install]
WantedBy=graphical-session.target
`
	if err := os.WriteFile(unitFile, []byte(unit), 0o644); err != nil {
		return err
	}

	if err := runCmd("systemctl", "--user", "daemon-reload"); err != nil {
		return fmt.Errorf("systemctl --user daemon-reload failed: %w", err)
	}
	_ = runCmd("systemctl", "--user", "enable", ServiceName)
	if err := runCmd("systemctl", "--user", "restart", ServiceName); err != nil {
		return fmt.Errorf("systemctl --user restart failed: %w", err)
	}
	return nil
}

func Uninstall(opts UninstallOptions) error {
	home, err := os.UserHomeDir()
	if err != nil {
		return err
	}
	installDir := filepath.Join(home, ".local", "share", ServiceName)
	configDir := filepath.Join(home, ".config", ServiceName)
	unitFile := filepath.Join(home, ".config", "systemd", "user", ServiceName+".service")

	if opts.DryRun {
		return nil
	}

	_ = runCmd("systemctl", "--user", "stop", ServiceName)
	_ = runCmd("systemctl", "--user", "disable", ServiceName)
	_ = runCmd("systemctl", "--user", "reset-failed", ServiceName)
	_ = os.Remove(unitFile)
	_ = runCmd("systemctl", "--user", "daemon-reload")
	_ = os.RemoveAll(installDir)
	if !opts.KeepConfig {
		_ = os.RemoveAll(configDir)
	}
	return nil
}

func buildLinuxAllowArgs(allowed []string) string {
	var b strings.Builder
	for _, p := range allowed {
		p = strings.TrimSpace(p)
		if p == "" {
			continue
		}
		pEsc := strings.ReplaceAll(p, "\"", "\\\"")
		b.WriteString(" -allow \"")
		b.WriteString(pEsc)
		b.WriteString("\"")
	}
	return b.String()
}

func escapeDoubleQuotes(s string) string {
	return strings.ReplaceAll(s, "\"", "\\\"")
}

func runCmd(name string, args ...string) error {
	cmd := exec.Command(name, args...)
	var stderr bytes.Buffer
	cmd.Stderr = &stderr
	cmd.Stdout = io.Discard
	if err := cmd.Run(); err != nil {
		msg := strings.TrimSpace(stderr.String())
		if msg != "" {
			return errors.New(msg)
		}
		return err
	}
	return nil
}