// Command cheapo lists and watches free game offers (Epic Games Store, Steam).
//
// Data is read from public storefront backends, no browser and no login
// needed. Reference implementations: vogler/free-games-claimer,
// jaixmario/free-games-notifier.
package main

import (
	"context"
	"encoding/json"
	"fmt"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/spf13/cobra"

	"gogs.netdome.biz/paul/cheapo/internal/game"
	"gogs.netdome.biz/paul/cheapo/internal/ops"
	"gogs.netdome.biz/paul/cheapo/internal/providers"
	"gogs.netdome.biz/paul/cheapo/internal/watch"
)

var (
	flagCountry string
	flagLocale  string
	flagJSON    bool
	flagStore   string
)

func main() {
	root := &cobra.Command{
		Use:   "cheapo",
		Short: "cheapo — free games lister (Go edition)",
		Long: `cheapo lists and watches free game offers (Epic Games Store, Steam).

Data is read from public storefront backends, no browser and no login needed.
References: https://github.com/vogler/free-games-claimer
            https://github.com/jaixmario/free-games-notifier`,
		SilenceUsage: true,
	}

	root.PersistentFlags().StringVar(&flagCountry, "country", "DE", "ISO country code for store region; determines currency/availability (epic only)")
	root.PersistentFlags().StringVar(&flagLocale, "locale", "de", "display locale for Epic (formatting only, e.g. de -> '22,39 €', en-US -> '€22.39'; currency comes from --country)")
	root.PersistentFlags().BoolVar(&flagJSON, "json", false, "output as JSON")
	root.PersistentFlags().StringVar(&flagStore, "store", "all", "which store(s): epic, steam, gog, all")

	root.AddCommand(listCmd(), watchCmd(), mcpCmd(), chattoSendCmd(), chattoRoomsCmd())

	if err := root.Execute(); err != nil {
		os.Exit(1)
	}
}

// newProviders returns the providers selected by --store.
func newProviders() ([]game.Provider, error) {
	return providers.New(providers.Options{
		Store:   flagStore,
		Country: flagCountry,
		Locale:  flagLocale,
	})
}

// fetchList runs ops.List over the providers selected by --store. A failing
// provider is reported on stderr but does not abort the others.
func fetchList(ctx context.Context, mode ops.Mode) ([]game.Game, error) {
	provs, err := newProviders()
	if err != nil {
		return nil, err
	}
	games, warnings, err := ops.List(ctx, provs, mode)
	if err != nil {
		return nil, err
	}
	for _, w := range warnings {
		fmt.Fprintf(os.Stderr, "⚠ %s\n", w)
	}
	return games, nil
}

// printGames renders games in CLI text form.
func printGames(cmd *cobra.Command, games []game.Game) error {
	if flagJSON {
		enc := json.NewEncoder(os.Stdout)
		enc.SetIndent("", "  ")
		return enc.Encode(games)
	}
	if len(games) == 0 {
		fmt.Fprintln(cmd.OutOrStdout(), "No matches.")
		return nil
	}
	out := cmd.OutOrStdout()
	for _, g := range games {
		fmt.Fprintf(out, "🎮 [%s] %s\n", g.Store, g.Title)
		if g.Kind != "" && g.Kind != "free-now" {
			fmt.Fprintf(out, "   Kind: %s\n", g.Kind)
		}
		if g.Seller != "" {
			fmt.Fprintf(out, "   By: %s\n", g.Seller)
		}
		if g.DiscountPct > 0 {
			if g.FinalPriceFmt != "" {
				fmt.Fprintf(out, "   Price: %s → %s (−%d %%)\n", g.PriceFmt, g.FinalPriceFmt, g.DiscountPct)
			} else {
				fmt.Fprintf(out, "   Price: %s (−%d %%)\n", g.PriceFmt, g.DiscountPct)
			}
		} else if g.PriceFmt != "" && g.Store != "steam" && g.PriceFmt != "0" {
			fmt.Fprintf(out, "   Instead of: %s\n", g.PriceFmt)
		}
		if g.Kind == "upcoming" && !g.StartDate.IsZero() {
			fmt.Fprintf(out, "   Free from: %s (until %s)\n",
				g.StartDate.Local().Format("02.01.2006 15:04"),
				g.EndDate.Local().Format("02.01.2006 15:04"))
		} else if !g.EndDate.IsZero() {
			fmt.Fprintf(out, "   Free until: %s\n", g.EndDate.UTC().Format(time.RFC3339))
		}
		fmt.Fprintf(out, "   %s\n", g.URL)
		fmt.Fprintln(out)
	}
	return nil
}

func listCmd() *cobra.Command {
	var (
		upcoming bool
		deals    bool
	)
	cmd := &cobra.Command{
		Use:     "list",
		Aliases: []string{"ls"},
		Short:   "List games currently free (optionally upcoming or deals)",
		RunE: func(cmd *cobra.Command, args []string) error {
			mode := ops.Free
			if upcoming {
				mode = ops.Upcoming
			} else if deals {
				mode = ops.Deals
			}

			games, err := fetchList(cmd.Context(), mode)
			if err != nil {
				return err
			}
			return printGames(cmd, games)
		},
	}
	cmd.Flags().BoolVar(&upcoming, "upcoming", false, "Show announced upcoming free games (Epic only)")
	cmd.Flags().BoolVar(&deals, "deals", false, "Show discounted games (deals) instead of free games")
	return cmd
}

func watchCmd() *cobra.Command {
	var (
		interval time.Duration
		once     bool
	)
	cmd := &cobra.Command{
		Use:   "watch",
		Short: "Wait for new free games (polling)",
		Long: `Polls all selected stores and reports every game that becomes newly free.
The first pass records the current state as the baseline (no reports).
A store that is currently unreachable does not abort watching.
Exit with Ctrl+C.`,
		RunE: func(cmd *cobra.Command, args []string) error {
			ctx, stop := signal.NotifyContext(cmd.Context(), os.Interrupt, syscall.SIGTERM)
			defer stop()

			provs, err := newProviders()
			if err != nil {
				return err
			}

			if once {
				var all []game.Game
				for _, p := range provs {
					games, err := p.GetFreeGames(ctx)
					if err != nil {
						fmt.Fprintf(os.Stderr, "⚠ %s: %v\n", p.Name(), err)
						continue
					}
					all = append(all, games...)
				}
				return printGames(cmd, all)
			}

			w := watch.NewWatcher(interval, provs...)
			return w.Run(ctx, false, watch.NotifierFunc(func(games []game.Game) {
				fmt.Fprintf(os.Stderr, "\n🔔 New free games (%s):\n", time.Now().Format("15:04:05"))
				for _, g := range games {
					end := "—"
					if !g.EndDate.IsZero() {
						end = g.EndDate.Local().Format("02.01.")
					}
					fmt.Fprintf(os.Stderr, "  🎮 [%s] %s — until %s — %s\n", g.Store, g.Title, end, g.URL)
				}
			}))
		},
	}
	cmd.Flags().DurationVar(&interval, "interval", 15*time.Minute, "Polling interval")
	cmd.Flags().BoolVar(&once, "once", false, "Check once and exit")
	return cmd
}