package main

import (
	"fmt"
	"os"
	"strings"
	"time"

	htmltomarkdown "github.com/JohannesKaufmann/html-to-markdown/v2"
	"github.com/JohannesKaufmann/html-to-markdown/v2/converter"
	"github.com/alexflint/go-arg"
	"github.com/imroc/req/v3"
)

var (
	version   string
	buildDate string
)

// Args defines the command-line arguments for mdget
type Args struct {
	URL       string `arg:"positional" help:"URL to fetch and convert to markdown"`
	Output    string `arg:"-o,--output" help:"Output file (default: stdout)" default:""`
	Timeout   int    `arg:"-t,--timeout" help:"Request timeout in seconds" default:"30"`
	UserAgent string `arg:"-u,--user-agent" help:"Custom User-Agent header" default:"mdget/0.1.0"`
}

// Version implements the Versioned interface for go-arg
func (Args) Version() string {
	return fmt.Sprintf("mdget v%s (built %s)", version, buildDate)
}

// Description returns the program description for help text
func (Args) Description() string {
	return "Fetch a URL and convert its HTML content to Markdown."
}

// Epilogue returns the help text epilogue
func (Args) Epilogue() string {
	return `Examples:
  mdget https://example.com
  mdget --output page.md https://example.com
  mdget --timeout 10 --user-agent "MyBot/1.0" example.com`
}

func main() {
	// Parse command-line arguments
	var args Args

	// Use MustParse which handles --help and --version automatically
	parser := arg.MustParse(&args)

	// Check if URL is provided (help/version flags are already handled by MustParse)
	if args.URL == "" {
		fmt.Fprintf(os.Stderr, "Error: URL is required\n\n")
		parser.WriteUsage(os.Stderr)
		os.Exit(1)
	}

	// Validate URL starts with http:// or https://
	url := args.URL
	if !strings.HasPrefix(url, "http://") && !strings.HasPrefix(url, "https://") {
		url = "https://" + url
	}

	// Determine output destination
	var output *os.File = os.Stdout
	if args.Output != "" {
		f, err := os.Create(args.Output)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Error creating output file: %v\n", err)
			os.Exit(1)
		}
		defer f.Close()
		output = f
	}

	// Fetch the URL using req with timeout and custom User-Agent
	client := req.C().
		SetTimeout(time.Duration(args.Timeout) * time.Second).
		SetUserAgent(args.UserAgent)

	resp, err := client.R().Get(url)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Error fetching URL: %v\n", err)
		os.Exit(1)
	}

	if !resp.IsSuccessState() {
		fmt.Fprintf(os.Stderr, "HTTP error: %s\n", resp.Status)
		os.Exit(1)
	}

	// Get HTML content
	html := resp.String()

	// Convert HTML to Markdown with domain context for relative URLs
	markdown, err := htmltomarkdown.ConvertString(
		html,
		converter.WithDomain(url),
	)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Error converting HTML to Markdown: %v\n", err)
		os.Exit(1)
	}

	// Output Markdown to destination
	fmt.Fprint(output, markdown)
}