package cli

import (
	"fmt"
	"os"
	"strings"

	"github.com/alexflint/go-arg"
)

var (
	Version   string
	BuildDate string
)

// Args represents command-line arguments.
type Args struct {
	FeedsFile string `arg:"--feeds-file,required" help:"Path to file containing RSS feed URLs (one per line)"`
	Prompt    string `arg:"--prompt,required" help:"User prompt for summarisation/analysis"`

	// Feed aggregation options
	MaxArticlesPerFeed int `arg:"--max-articles-per-feed" help:"Maximum articles to fetch from each feed" default:"10"`
	MaxDaysOld         int `arg:"--max-days-old" help:"Only include articles from the last N days (0 for all)" default:"7"`
	MaxTotalArticles   int `arg:"--max-total-articles" help:"Maximum total articles to process" default:"20"`

	// Content filtering
	IncludeKeywords string `arg:"--include-keywords" help:"Comma-separated list of keywords to include (case-insensitive)"`
	ExcludeKeywords string `arg:"--exclude-keywords" help:"Comma-separated list of keywords to exclude (case-insensitive)"`

	// Deepseek API options
	APIKey      string  `arg:"--api-key" help:"Deepseek API key (default: read from DEEPSEEK_API_KEY env var)"`
	Model       string  `arg:"--model" help:"Deepseek model to use" default:"deepseek-chat"`
	MaxTokens   int     `arg:"--max-tokens" help:"Maximum tokens in response" default:"4000"`
	Temperature float64 `arg:"--temperature" help:"Sampling temperature (0.0 to 1.0)" default:"0.7"`

	// Output options
	Output          string `arg:"--output" help:"Output format" default:"text" choice:"text,json,markdown"`
	OutputFile      string `arg:"--output-file" help:"Write output to file (default: stdout)"`
	IncludeArticles bool   `arg:"--include-articles" help:"Include original articles in JSON output"`

	// System options
	SystemPrompt string `arg:"--system-prompt" help:"Custom system prompt for Deepseek"`
	TUI          bool   `arg:"--tui" help:"Enable TUI interface with progress bar"`
	Verbose      bool   `arg:"-v,--verbose" help:"Show verbose output"`
	ShowVersion  bool   `arg:"--version" help:"Show version"`
}

// Version returns the version string.
func (Args) Version() string {
	return fmt.Sprintf("llm_aggregator v%s (built %s)", Version, BuildDate)
}

// Description returns the program description.
func (Args) Description() string {
	return `LLM Aggregator - Aggregate RSS feeds and summarise with Deepseek API

Examples:
  # Basic usage with prompts
  llm_aggregator --feeds-file feeds.txt --prompt "What are the latest trends in free software?"
  
  # With custom Deepseek model
  llm_aggregator --feeds-file feeds.txt --prompt "Summarise tech news" --model deepseek-coder
  
  # Output to JSON file
  llm_aggregator --feeds-file feeds.txt --prompt "Analyse AI developments" --output json --output-file analysis.json
  
  # Filter by keywords
  llm_aggregator --feeds-file feeds.txt --prompt "Linux news" --include-keywords linux,opensource

Environment Variables:
  DEEPSEEK_API_KEY: Your Deepseek API key (required if not provided via --api-key)`
}

// ParseKeywords parses comma-separated keywords string into list.
func ParseKeywords(keywordString string) []string {
	if keywordString == "" {
		return nil
	}
	keywords := strings.Split(keywordString, ",")
	result := make([]string, 0, len(keywords))
	for _, kw := range keywords {
		if trimmed := strings.TrimSpace(kw); trimmed != "" {
			result = append(result, trimmed)
		}
	}
	return result
}

// ParseArgs parses command line arguments.
func ParseArgs() (*Args, error) {
	var args Args
	parser, err := arg.NewParser(arg.Config{
		Program: "llm_aggregator",
	}, &args)
	if err != nil {
		return nil, err
	}

	// Handle help and version flags before checking required fields
	if len(os.Args) > 1 {
		if os.Args[1] == "-h" || os.Args[1] == "--help" {
			parser.WriteHelp(os.Stdout)
			os.Exit(0)
		}
		if os.Args[1] == "--version" {
			fmt.Printf("llm_aggregator v%s (built %s)", Version, BuildDate)
			os.Exit(0)
		}
	}

	err = parser.Parse(os.Args[1:])
	if err != nil {
		return nil, err
	}

	return &args, nil
}