package birdfmt

import (
	"bytes"
	"context"
	"fmt"
	"os/exec"
	"strings"
)

// BirdCtl runs bird(8) and birdc(8) for parse checks and configure reload.
type BirdCtl struct {
	// Bird is the bird binary path (default "bird").
	Bird string
	// Birdc is the birdc binary path (default "birdc").
	Birdc string
	// Socket is optional birdc control socket (-s); empty uses birdc default.
	Socket string
}

func (c *BirdCtl) birdBin() string {
	if strings.TrimSpace(c.Bird) != "" {
		return c.Bird
	}
	return "bird"
}

func (c *BirdCtl) birdcBin() string {
	if strings.TrimSpace(c.Birdc) != "" {
		return c.Birdc
	}
	return "birdc"
}

// ParseCheck runs `bird -c <mainConfigPath> -p` to validate syntax without starting the daemon.
func (c *BirdCtl) ParseCheck(ctx context.Context, mainConfigPath string) error {
	mainConfigPath = strings.TrimSpace(mainConfigPath)
	if mainConfigPath == "" {
		return fmt.Errorf("birdfmt: main config path is required for parse check")
	}
	cmd := exec.CommandContext(ctx, c.birdBin(), "-c", mainConfigPath, "-p")
	var stderr bytes.Buffer
	cmd.Stderr = &stderr
	if err := cmd.Run(); err != nil {
		msg := strings.TrimSpace(stderr.String())
		if msg != "" {
			return fmt.Errorf("bird -p: %w: %s", err, msg)
		}
		return fmt.Errorf("bird -p: %w", err)
	}
	return nil
}

// Configure runs `birdc configure` to load the current config from disk (BIRD 2).
func (c *BirdCtl) Configure(ctx context.Context) error {
	args := []string{"configure"}
	if s := strings.TrimSpace(c.Socket); s != "" {
		args = append([]string{"-s", s}, args...)
	}
	cmd := exec.CommandContext(ctx, c.birdcBin(), args...)
	var stderr bytes.Buffer
	cmd.Stderr = &stderr
	if err := cmd.Run(); err != nil {
		msg := strings.TrimSpace(stderr.String())
		if msg != "" {
			return fmt.Errorf("birdc configure: %w: %s", err, msg)
		}
		return fmt.Errorf("birdc configure: %w", err)
	}
	return nil
}