package app

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

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

var newObjectStoreFromConfigFn = storage.NewObjectStoreFromConfig
var discoverRemoteCurrentStateFn = discoverRemoteCurrentState
var buildRestorePlanFn = buildRestorePlan

// Restore validates restore CLI/config inputs and storage preflight for future restore phases.
func Restore(ctx context.Context, args []string, out io.Writer) error {
	fs := flag.NewFlagSet("restore", flag.ContinueOnError)
	fs.SetOutput(out)

	var pipelinePath string
	var sessionPath string
	var sessionID string
	var dryRun bool
	var force bool
	var includeAudio bool
	fs.StringVar(&pipelinePath, "config", "", "path to pipeline.yml (optional; defaults searched)")
	fs.StringVar(&sessionPath, "session", "", "path to session.yml")
	fs.StringVar(&sessionID, "session-id", "", "session identifier for session.yml templates")
	fs.BoolVar(&dryRun, "dry-run", false, "plan restore actions without writing local files")
	fs.BoolVar(&force, "force", false, "overwrite local conflicts with remote state")
	fs.BoolVar(&includeAudio, "include-audio", false, "include archived session-level audio objects")
	fs.Usage = func() {
		_, _ = fmt.Fprintln(out, "Usage: narratio restore [--config <path>] [--session <path>] [--session-id <value>] [--dry-run] [--force] [--include-audio]")
		_, _ = fmt.Fprintln(out)
		_, _ = fmt.Fprintln(out, "Flags:")
		fs.PrintDefaults()
	}

	if err := fs.Parse(args); err != nil {
		if errors.Is(err, flag.ErrHelp) {
			return nil
		}
		return fmt.Errorf("restore: invalid flags: %w", err)
	}
	if fs.NArg() != 0 {
		return fmt.Errorf("restore: unexpected positional arguments")
	}
	resolvedPipelinePath, err := resolvePipelineConfigPath(pipelinePath)
	if err != nil {
		return fmt.Errorf("restore: %w", err)
	}
	resolvedSessionPath, err := resolveSessionConfigPath(sessionPath)
	if err != nil {
		return fmt.Errorf("restore: %w", err)
	}

	cfg, err := config.LoadWithSessionOptions(resolvedPipelinePath, resolvedSessionPath, config.SessionLoadOptions{
		SessionID: sessionID,
	})
	if err != nil {
		return fmt.Errorf("restore: %w", err)
	}
	if err := config.Validate(cfg); err != nil {
		return fmt.Errorf("restore: %w", err)
	}

	objectStore, err := newObjectStoreFromConfigFn(ctx, cfg)
	if err != nil {
		return fmt.Errorf("restore: %w", err)
	}
	current, err := discoverRemoteCurrentStateFn(ctx, cfg, objectStore)
	if err != nil {
		return fmt.Errorf("restore: %w", err)
	}
	plan, err := buildRestorePlanFn(ctx, cfg, current, objectStore, RestorePlanOptions{
		IncludeAudio: includeAudio,
		Force:        force,
		DryRun:       dryRun,
	})
	if err != nil {
		return fmt.Errorf("restore: %w", err)
	}
	if err := writeRestorePlan(out, current, plan, RestorePlanOptions{
		IncludeAudio: includeAudio,
		Force:        force,
		DryRun:       dryRun,
	}); err != nil {
		return fmt.Errorf("restore: write plan output: %w", err)
	}
	if dryRun {
		return nil
	}
	if plan.ConflictCount > 0 && !force {
		return fmt.Errorf(
			"restore: plan has %d conflicting path(s); rerun with --force or resolve local conflicts",
			plan.ConflictCount,
		)
	}
	return fmt.Errorf(
		"restore: planned remote restore for %s/%s (run %s); not yet implemented (phase 4: restore execution)",
		current.Campaign,
		current.SessionID,
		current.RunID,
	)
}