package stage

import (
	"context"
	"fmt"

	"gitea.maximumdirect.net/eric/narratio/internal/artifacts"
	"gitea.maximumdirect.net/eric/narratio/internal/manifest"
)

const placeholderMessage = "placeholder stage: no real work executed"

type placeholderStage struct {
	name string
}

func (s placeholderStage) Name() string { return s.name }

func (s placeholderStage) Declares() IODecl {
	return IODecl{
		Inputs:  []artifacts.Ref{{Kind: "artifact", Category: "input", RelativePath: s.name + ".input.placeholder"}},
		Outputs: []artifacts.Ref{{Kind: "artifact", Category: "output", RelativePath: s.name + ".output.placeholder"}},
	}
}

func (s placeholderStage) Run(_ context.Context, _ *Env, _ *manifest.Manifest) (*StageResult, error) {
	return &StageResult{
		Metadata: map[string]any{
			"placeholder": true,
			"stage":       s.name,
			"message":     placeholderMessage,
		},
	}, nil
}

// All returns the canonical ordered stage list for full pipeline execution.
func All() []Stage {
	return []Stage{
		placeholderStage{name: "prepare"},
		placeholderStage{name: "transcribe"},
		placeholderStage{name: "normalize"},
		placeholderStage{name: "merge"},
		placeholderStage{name: "polish"},
		placeholderStage{name: "analyze"},
		placeholderStage{name: "archive"},
		placeholderStage{name: "notify"},
	}
}

// Select returns one stage by exact name from the canonical stage set.
func Select(name string) (Stage, error) {
	for _, s := range All() {
		if s.Name() == name {
			return s, nil
		}
	}
	return nil, fmt.Errorf("unknown stage %q", name)
}