package output

import (
	"context"
	"fmt"
	"net"

	"github.com/hits/ExploreDNS/internal/fingerprint"
	"github.com/hits/ExploreDNS/internal/traverse"
)

// RunTraversal is the high-level entry point that wires together a Traverser,
// a Config, and a Formatter.  It:
//
//  1. Attaches output hooks to traverser so events are formatted in real time.
//  2. Calls traverser.Traverse(ctx, domain) to perform the traversal.
//  3. Optionally fingerprints encountered servers (when ShowVersions && ShowServers).
//  4. Writes the summary and flushes the formatter.
//
// Returns all TraversalResults and any error from the traversal or output.
func RunTraversal(ctx context.Context, traverser *traverse.Traverser, cfg *Config, formatter Formatter, domain string) ([]traverse.TraversalResult, error) {
	if traverser == nil {
		return nil, fmt.Errorf("traverser is required")
	}
	if cfg == nil {
		cfg = DefaultConfig()
	}
	if formatter == nil {
		formatter = NewFormatter(cfg, nil)
	}

	traverser.SetHooks(AttachHooks(cfg, formatter))

	results, err := traverser.Traverse(ctx, domain)
	if err != nil {
		return results, err
	}

	// Fingerprint servers when both ShowVersions and ShowServers are enabled.
	// Gating on ShowServers avoids unnecessary network calls when versions
	// would not be displayed anyway.
	if cfg.ShowVersions && cfg.ShowServers {
		cfg.Fingerprints = fingerprint.New().FingerprintAll(ctx, collectUniqueServerIPs(results))
	}

	if err := formatter.WriteSummary(results); err != nil {
		return results, err
	}
	if err := formatter.Flush(); err != nil {
		return results, err
	}

	return results, nil
}

// collectUniqueServerIPs returns the set of unique server IPs seen in results.
func collectUniqueServerIPs(results []traverse.TraversalResult) []net.IP {
	seen := make(map[string]bool)
	var ips []net.IP
	for _, r := range results {
		if r.Response == nil || r.Response.Server == nil {
			continue
		}
		key := r.Response.Server.String()
		if !seen[key] {
			seen[key] = true
			ips = append(ips, r.Response.Server)
		}
	}
	return ips
}