package main

import (
	"flag"
	"fmt"
	"log"
	"os"
	"regexp"
	"strings"
	"time"

	"gitea.r8z.us/stwhite/arxiva"
	"gitea.r8z.us/stwhite/paperformatter"
	"gitea.r8z.us/stwhite/paperprocessor"
)

// sanitizeFilename replaces invalid filename characters to match arxiva's sanitization
func sanitizeFilename(s string) string {
	s = strings.ReplaceAll(s, ":", "_")
	s = strings.ReplaceAll(s, " ", "_")
	return s
}

// isValidDate checks if the date string is in YYYYMMDD format
func isValidDate(date string) bool {
	// Check basic format with regex
	matched, err := regexp.MatchString(`^\d{8}$`, date)
	if err != nil || !matched {
		return false
	}

	// Parse date to verify it's a valid date
	_, err = time.Parse("20060102", date)
	return err == nil
}

func main() {
	// Set custom usage message
	flag.Usage = func() {
		fmt.Fprintf(os.Stderr, "Usage: %s [options]\n\n", os.Args[0])
		fmt.Fprintf(os.Stderr, "Description:\n")
		fmt.Fprintf(os.Stderr, "  Fetches papers from arXiv, processes them using an LLM, and generates both JSON and Markdown outputs.\n\n")
		fmt.Fprintf(os.Stderr, "Pipeline:\n")
		fmt.Fprintf(os.Stderr, "  1. Fetches papers from arXiv based on date range and query\n")
		fmt.Fprintf(os.Stderr, "  2. Saves raw papers to JSON (format: YYYYMMDD-YYYYMMDD-query.json)\n")
		fmt.Fprintf(os.Stderr, "  3. Processes papers using specified LLM model\n")
		fmt.Fprintf(os.Stderr, "  4. Formats results to both JSON and Markdown\n\n")
		fmt.Fprintf(os.Stderr, "Required flags:\n")
		fmt.Fprintf(os.Stderr, "  -start     : Start date (YYYYMMDD)\n")
		fmt.Fprintf(os.Stderr, "  -end       : End date (YYYYMMDD)\n")
		fmt.Fprintf(os.Stderr, "  -query     : Search query\n")
		fmt.Fprintf(os.Stderr, "  -api-key   : API key for LLM service\n\n")
		fmt.Fprintf(os.Stderr, "Options:\n")
		flag.PrintDefaults()
		fmt.Fprintf(os.Stderr, "\nExamples:\n")
		fmt.Fprintf(os.Stderr, "  Basic usage:\n")
		fmt.Fprintf(os.Stderr, "    %s -start 20240101 -end 20240131 -query \"machine learning\" -api-key \"your-key\"\n\n", os.Args[0])
		fmt.Fprintf(os.Stderr, "  With custom model and outputs:\n")
		fmt.Fprintf(os.Stderr, "    %s -start 20240101 -end 20240131 -query \"machine learning\" -api-key \"your-key\" \\\n", os.Args[0])
		fmt.Fprintf(os.Stderr, "      -model \"gpt-4\" -json-output \"results.json\" -md-output \"summary.md\"\n")
	}

	// Parse command line arguments
	startDate := flag.String("start", "", "Start date in YYYYMMDD format")
	endDate := flag.String("end", "", "End date in YYYYMMDD format")
	query := flag.String("query", "", "Search query")
	maxResults := flag.Int("maxResults", 100, "Maximum number of results (1-2000)")
	model := flag.String("model", "phi-4", "Model to use for processing")
	apiKey := flag.String("api-key", "", "API key for service authentication")
	apiEndpoint := flag.String("api-endpoint", "http://localhost:1234/v1/chat/completions", "API endpoint URL")
	criteriaFile := flag.String("criteria", "criteria.md", "Path to evaluation criteria markdown file")
	jsonOutput := flag.String("json-output", "", "JSON output file path (default: YYYYMMDD-YYYYMMDD-query.json)")
	mdOutput := flag.String("md-output", "", "Markdown output file path (default: YYYYMMDD-YYYYMMDD-query.md)")
	flag.Parse()

	// Generate base filename from parameters with sanitization
	baseFilename := fmt.Sprintf("%s-%s-%s", *startDate, *endDate, sanitizeFilename(*query))

	// Set default output filenames if not provided
	if *jsonOutput == "" {
		*jsonOutput = baseFilename + ".json"
	}
	if *mdOutput == "" {
		*mdOutput = baseFilename + ".md"
	}

	// Validate required flags
	if *startDate == "" || *endDate == "" || *query == "" || *apiKey == "" {
		fmt.Fprintf(os.Stderr, "Error: start date, end date, query, and api-key are required\n\n")
		flag.Usage()
		os.Exit(1)
	}

	// Validate date format
	if !isValidDate(*startDate) || !isValidDate(*endDate) {
		fmt.Fprintf(os.Stderr, "Error: dates must be in YYYYMMDD format\n")
		os.Exit(1)
	}

	// Validate maxResults range
	if *maxResults < 1 || *maxResults > 2000 {
		fmt.Fprintf(os.Stderr, "Error: maxResults must be between 1 and 2000\n")
		os.Exit(1)
	}

	// Create processor configuration
	config := paperprocessor.Config{
		APIEndpoint:  *apiEndpoint,
		APIKey:       *apiKey,
		Model:        *model,
		RequestDelay: 2 * time.Second,
	}

	// Fetch papers using command line args
	papers, err := arxiva.FetchPapers(*startDate, *endDate, *query, *maxResults)
	if err != nil {
		log.Fatalf("Failed to fetch papers: %v", err)
	}

	// Save papers to JSON file using the same naming convention
	if err := arxiva.SaveToFile(papers, *startDate, *endDate, *query); err != nil {
		log.Fatalf("Failed to save papers: %v", err)
	}

	// Wait briefly for file system to sync and verify file exists
	time.Sleep(100 * time.Millisecond)
	if _, err := os.Stat(baseFilename + ".json"); os.IsNotExist(err) {
		log.Fatalf("Failed to find saved papers file: %s", baseFilename+".json")
	}

	// Process the saved file using the base filename
	if err := paperprocessor.ProcessFile(
		baseFilename+".json",
		*jsonOutput,
		*criteriaFile,
		config,
	); err != nil {
		log.Fatalf("Processing failed: %v", err)
	}

	// Format the processed results to markdown
	if err := paperformatter.FormatPapers(*jsonOutput, *mdOutput); err != nil {
		log.Fatalf("Formatting failed: %v", err)
	}

	log.Printf("Successfully processed papers. Results written to %s and formatted to %s", *jsonOutput, *mdOutput)
}