package birdfmt

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

// ShowProtocols runs `birdc [-s socket] show protocols all` and returns stdout (BIRD 2).
func ShowProtocols(ctx context.Context, socket, birdcBin string) (string, error) {
	if birdcBin == "" {
		birdcBin = "birdc"
	}
	args := []string{"show", "protocols", "all"}
	if s := strings.TrimSpace(socket); s != "" {
		args = append([]string{"-s", s}, args...)
	}
	cmd := exec.CommandContext(ctx, birdcBin, args...)
	var stdout, stderr bytes.Buffer
	cmd.Stdout = &stdout
	cmd.Stderr = &stderr
	if err := cmd.Run(); err != nil {
		msg := strings.TrimSpace(stderr.String())
		if msg != "" {
			return "", fmt.Errorf("birdc show protocols: %w: %s", err, msg)
		}
		return "", fmt.Errorf("birdc show protocols: %w", err)
	}
	return stdout.String(), nil
}

// CountEstablishedBGPSessions counts BGP protocol rows whose line contains "Established"
// (heuristic for `birdc show protocols` / `show protocols all` output).
func CountEstablishedBGPSessions(showProtocolsOutput string) int {
	lines := strings.Split(showProtocolsOutput, "\n")
	n := 0
	for _, line := range lines {
		line = strings.TrimSpace(line)
		if line == "" || strings.HasPrefix(line, "name") || strings.HasPrefix(strings.ToLower(line), "table") {
			continue
		}
		if !isBGPProtocolSummaryRow(line) {
			continue
		}
		if strings.Contains(strings.ToLower(line), "established") {
			n++
		}
	}
	return n
}

// ParseBGPProtocolStates parses `birdc show protocols all` summary rows into protocol_name -> state.
func ParseBGPProtocolStates(output string) map[string]string {
	out := make(map[string]string)
	for _, raw := range strings.Split(output, "\n") {
		line := strings.TrimSpace(raw)
		if line == "" {
			continue
		}
		low := strings.ToLower(line)
		if strings.HasPrefix(low, "bird ") || strings.HasPrefix(low, "name ") || strings.HasPrefix(low, "table ") {
			continue
		}
		fields := strings.Fields(line)
		if len(fields) < 4 {
			continue
		}
		if !strings.EqualFold(fields[1], "BGP") {
			continue
		}
		state := extractBGPSessionStateLine(line)
		if state == "" {
			state = fields[3]
		}
		out[fields[0]] = state
	}
	return out
}

func extractBGPSessionStateLine(line string) string {
	known := []string{
		"Established",
		"Idle",
		"Connect",
		"Active",
		"OpenSent",
		"OpenConfirm",
	}
	for _, st := range known {
		if strings.Contains(line, st) {
			return st
		}
	}
	return ""
}