package app

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

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

// Run executes the placeholder stage pipeline and persists manifest state.
func Run(ctx context.Context, args []string, out io.Writer) error {
	fs := flag.NewFlagSet("run", flag.ContinueOnError)
	fs.SetOutput(io.Discard)

	var pipelinePath string
	var sessionPath string
	var force bool
	fs.StringVar(&pipelinePath, "config", "", "path to pipeline.yml")
	fs.StringVar(&sessionPath, "session", "", "path to session.yml")
	fs.BoolVar(&force, "force", false, "force stage execution (reserved for future behavior)")

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

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

	stages := BuildFullPlan()
	summary, err := executeStages(ctx, cfg, stages, RunOptions{Force: force})
	if err != nil {
		return fmt.Errorf("run: %w", err)
	}

	_, err = fmt.Fprintf(out, "narratio run: completed %d placeholder stages for session %s; manifest updated at %s\n", len(summary.StageNames), summary.SessionID, summary.ManifestPath)
	return err
}