package majordomo

import (
	"context"
	"fmt"

	"gitea.stevedudenhoeffer.com/steve/majordomo/llm"
)

// Built-in provider names. Real client implementations land per-phase
// (see progress.md); until a provider's phase ships, its registration is a
// stub that resolves (so specs parse and env DSNs load) but errors on use.
const (
	ProviderOpenAI      = "openai"
	ProviderAnthropic   = "anthropic"
	ProviderGoogle      = "google"
	ProviderOllama      = "ollama"
	ProviderOllamaCloud = "ollama-cloud"
	ProviderForeman     = "foreman"
)

// registerBuiltins installs the built-in providers and env-DSN scheme
// factories into a fresh registry.
func registerBuiltins(r *Registry) {
	stub := func(kind string) SchemeFactory {
		return func(name string, dsn DSN) (llm.Provider, error) {
			return &stubProvider{name: name, kind: kind, baseURL: dsn.BaseURL(), token: dsn.Token}, nil
		}
	}

	for _, kind := range []string{
		ProviderOpenAI, ProviderAnthropic, ProviderGoogle,
		ProviderOllama, ProviderOllamaCloud, ProviderForeman,
	} {
		r.providers[kind] = &stubProvider{name: kind, kind: kind}
		r.schemes[kind] = stub(kind)
	}
	// "gemini" is an alternate scheme for the Google provider.
	r.schemes["gemini"] = stub(ProviderGoogle)
}

// stubProvider stands in for a provider implementation that lands in a
// later phase. It resolves and carries its connection details (so Parse,
// chains, and env loading are fully functional) but errors on use.
type stubProvider struct {
	name    string
	kind    string
	baseURL string
	token   string
}

func (s *stubProvider) Name() string { return s.name }

func (s *stubProvider) Model(id string, opts ...llm.ModelOption) (llm.Model, error) {
	cfg := llm.ApplyModelOptions(opts)
	return &stubModel{provider: s, id: id, cfg: cfg}, nil
}

type stubModel struct {
	provider *stubProvider
	id       string
	cfg      llm.ModelConfig
}

func (m *stubModel) err() error {
	return fmt.Errorf("majordomo: provider %q (%s) is not implemented yet", m.provider.name, m.provider.kind)
}

func (m *stubModel) Generate(context.Context, llm.Request, ...llm.Option) (*llm.Response, error) {
	return nil, m.err()
}

func (m *stubModel) Stream(context.Context, llm.Request, ...llm.Option) (llm.Stream, error) {
	return nil, m.err()
}

func (m *stubModel) Capabilities() llm.Capabilities {
	if m.cfg.Capabilities != nil {
		return *m.cfg.Capabilities
	}
	return llm.Capabilities{}
}