package app

import (
	"context"
	"flag"
	"fmt"
	"io"

	"gitea.maximumdirect.net/eric/narratio/internal/config"
)

// Plan validates configuration inputs and reports readiness for future planning.
func Plan(_ context.Context, args []string, out io.Writer) error {
	fs := flag.NewFlagSet("plan", flag.ContinueOnError)
	fs.SetOutput(io.Discard)

	var pipelinePath string
	var sessionPath string
	fs.StringVar(&pipelinePath, "config", "", "path to pipeline.yml")
	fs.StringVar(&sessionPath, "session", "", "path to session.yml")

	if err := fs.Parse(args); err != nil {
		return fmt.Errorf("plan: invalid flags: %w", err)
	}
	if fs.NArg() != 0 {
		return fmt.Errorf("plan: unexpected positional arguments")
	}
	if pipelinePath == "" || sessionPath == "" {
		return fmt.Errorf("plan: --config and --session are required")
	}

	cfg, err := config.Load(pipelinePath, sessionPath)
	if err != nil {
		return fmt.Errorf("plan: %w", err)
	}
	if err := config.Validate(cfg); err != nil {
		return fmt.Errorf("plan: %w", err)
	}

	_, err = fmt.Fprintln(out, "narratio plan: configuration loaded and valid")
	return err
}