package main

import (
	"encoding/json"
	"fmt"
	"os"
	"sync"
	"time"
)

// LogWriter handles writing log lines to a file.
type LogWriter struct {
	file       *os.File
	mu         sync.Mutex
	errorsOnly bool
}

func NewLogWriter(path string, errorsOnly bool) (*LogWriter, error) {
	f, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0644)
	if err != nil {
		return nil, err
	}
	return &LogWriter{file: f, errorsOnly: errorsOnly}, nil
}

func (lw *LogWriter) Write(line string, isError bool) {
	if lw.errorsOnly && !isError {
		return
	}
	lw.mu.Lock()
	defer lw.mu.Unlock()
	fmt.Fprintln(lw.file, line)
}

func (lw *LogWriter) Close() error {
	return lw.file.Close()
}

// formatLogLine creates a concise one-line log for a processed host.
func formatLogLine(host Host, result ProcessResult) string {
	title := result.Title
	if len(title) > 20 {
		title = title[:20] + "..."
	}

	if result.Err != nil {
		errType := "parse"
		if result.FetchErr {
			errType = "fetch"
		}
		return fmt.Sprintf("parsed: %s err:%s %v", host.Hostname, errType, result.Err)
	}

	iconCount := len(result.Icons) + 1 // +1 for /favicon.ico
	iframe := "iframe:ok"
	if !result.IframeAllowed {
		iframe = "iframe:no"
	}

	return fmt.Sprintf("parsed: %s \"%s\" icons:%d %s", host.Hostname, title, iconCount, iframe)
}

// writeStats writes the stage stats to a JSON file.
func writeStats(stats *Stats, cfg Config) {
	finishedAt := time.Now()
	duration := finishedAt.Sub(stats.StartedAt)

	data := map[string]interface{}{
		"started_at":       stats.StartedAt.Format(time.RFC3339),
		"finished_at":      finishedAt.Format(time.RFC3339),
		"duration_seconds": int(duration.Seconds()),
		"processed":        stats.Processed.Load(),
		"titles_found":     stats.TitlesFound.Load(),
		"no_title":         stats.NoTitle.Load(),
		"icons_found":      stats.IconsFound.Load(),
		"iframe_blocked":   stats.IframeBlocked.Load(),
		"fetch_errors":     stats.FetchErrors.Load(),
		"parse_errors":     stats.ParseErrors.Load(),
		"db_errors":        stats.DBErrors.Load(),
		"panics":           stats.Panics.Load(),
	}

	os.MkdirAll("stats", 0755)
	f, err := os.Create("stats/02_warc_parse.json")
	if err != nil {
		fmt.Printf("Failed to write stats: %v\n", err)
		return
	}
	defer f.Close()

	enc := json.NewEncoder(f)
	enc.SetIndent("", "  ")
	enc.Encode(data)
	fmt.Println("Stats written to stats/02_warc_parse.json")
}