package pipeline

import (
	"fmt"
	"strings"

	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
)

type OutputEncoderConstructor func() (contracts.OutputEncoder, error)

type OutputEncoderRegistry struct {
	constructors map[string]OutputEncoderConstructor
	specs        map[string]ModuleSpec
}

func NewOutputEncoderRegistry() *OutputEncoderRegistry {
	return &OutputEncoderRegistry{
		constructors: make(map[string]OutputEncoderConstructor),
		specs:        make(map[string]ModuleSpec),
	}
}

func (r *OutputEncoderRegistry) Register(key string, constructor OutputEncoderConstructor) error {
	return r.RegisterWithSpec(defaultModuleSpec(key, StageOutput), constructor)
}

func (r *OutputEncoderRegistry) RegisterWithSpec(spec ModuleSpec, constructor OutputEncoderConstructor) error {
	if r == nil {
		return fmt.Errorf("output encoder registry must not be nil")
	}

	normalizedSpec := normalizeModuleSpec(spec)
	if err := validateModuleSpec("output encoder", StageOutput, normalizedSpec); err != nil {
		return err
	}
	if constructor == nil {
		return fmt.Errorf("output encoder constructor for %q must not be nil", normalizedSpec.Key)
	}
	if _, ok := r.constructors[normalizedSpec.Key]; ok {
		return fmt.Errorf("output encoder %q is already registered", normalizedSpec.Key)
	}

	if r.constructors == nil {
		r.constructors = make(map[string]OutputEncoderConstructor)
	}
	if r.specs == nil {
		r.specs = make(map[string]ModuleSpec)
	}
	r.constructors[normalizedSpec.Key] = constructor
	r.specs[normalizedSpec.Key] = cloneModuleSpec(normalizedSpec)
	return nil
}

func (r *OutputEncoderRegistry) Build(key string) (contracts.OutputEncoder, error) {
	if r == nil {
		return nil, fmt.Errorf("output encoder registry must not be nil")
	}

	normalizedKey := strings.TrimSpace(key)
	if normalizedKey == "" {
		return nil, fmt.Errorf("output encoder key must not be empty")
	}

	constructor, ok := r.constructors[normalizedKey]
	if !ok {
		return nil, fmt.Errorf("output encoder %q is not registered", normalizedKey)
	}

	encoder, err := constructor()
	if err != nil {
		return nil, fmt.Errorf("build output encoder %q: %w", normalizedKey, err)
	}
	if encoder == nil {
		return nil, fmt.Errorf("output encoder %q constructor returned nil", normalizedKey)
	}
	if encoder.Key() != normalizedKey {
		return nil, fmt.Errorf("output encoder %q returned key %q", normalizedKey, encoder.Key())
	}

	return encoder, nil
}

func (r *OutputEncoderRegistry) Spec(key string) (ModuleSpec, bool) {
	if r == nil {
		return ModuleSpec{}, false
	}

	spec, ok := r.specs[strings.TrimSpace(key)]
	if !ok {
		return ModuleSpec{}, false
	}
	return cloneModuleSpec(spec), true
}

func (r *OutputEncoderRegistry) RegisteredKeys() []string {
	if r == nil {
		return nil
	}

	return sortedRegistryKeys(r.constructors)
}