package promptkit

import (
	"gitea.maximumdirect.net/eric/ConfigKit"
	"gitea.maximumdirect.net/eric/promptkit/internal/backend"
)

// BackendOpenRouter is the conventional ID for an OpenRouter backend.
const BackendOpenRouter = backend.OpenRouterID

// BackendRakestrawHome is the conventional ID for a Rakestrawhome backend.
const BackendRakestrawHome = backend.RakestrawHomeID

// BackendLocal is a conventional ID for a caller-configured local backend.
const BackendLocal = "local"

// BackendConfig is a presence-aware convenience value for a keyed backend
// definition. Nil pointer fields are omitted, while non-nil pointers preserve
// explicit zero or blank values. A nil ExtraParams map is omitted; a non-nil
// empty map supplies an empty mapping. A nil SmokeTests pointer is omitted; a
// non-nil pointer supplies a smoke_tests mapping. Use raw ConfigKit Mapping
// inputs for explicit null. BackendConfig has no stable JSON representation.
type BackendConfig struct {
	// Endpoint is the required absolute HTTP(S) base URL after all layers merge.
	Endpoint *string
	// APIKeyEnv optionally names an environment variable, not a credential.
	APIKeyEnv *string
	// ConcurrencyLimit is zero for unlimited generation; negative is invalid.
	ConcurrencyLimit *int
	// QueueCapacity defaults to 1024 for positive concurrency when omitted.
	// An explicit value, including zero, requires positive concurrency.
	QueueCapacity *int
	// ExtraParams supplies JSON-compatible provider request defaults.
	ExtraParams map[string]any
	// SmokeTests supplies optional diagnostic defaults and HTTP probe settings.
	SmokeTests *BackendSmokeTestConfig
}

// BackendSmokeTestConfig contains optional diagnostic settings associated with
// a backend. Nil nested fields are omitted by BackendSource.
type BackendSmokeTestConfig struct {
	// DefaultProfile is the exact profile ID selected as the backend's
	// diagnostic inference default. A supplied value must not be blank; the ID
	// is resolved only when that default is selected.
	DefaultProfile *string
	// Reachability optionally selects a full HTTP destination for reachability
	// diagnostics. A nil endpoint uses the effective backend endpoint.
	Reachability *ReachabilityProbeConfig
	// Authentication optionally declares a named authentication diagnostic.
	// A supplied object requires Kind.
	Authentication *AuthenticationProbeConfig
}

// ReachabilityProbeConfig configures an optional reachability destination.
type ReachabilityProbeConfig struct {
	// Endpoint is an absolute HTTP(S) URL, including any desired path or query.
	// Nil selects the effective backend endpoint; an explicit blank value is
	// invalid.
	Endpoint *string
}

// AuthenticationProbeConfig configures an optional named authentication
// diagnostic.
type AuthenticationProbeConfig struct {
	// Kind selects the authentication adapter. Supported values are "none" and
	// "openrouter_key"; surrounding whitespace and case are normalized.
	Kind *string
	// Endpoint is an absolute HTTP(S) URL, including any desired path or query.
	// Nil selects the adapter's backend-relative destination; an explicit blank
	// value is invalid.
	Endpoint *string
}

// BackendSource creates a labeled ConfigKit mapping from keyed backend values.
// It encodes fields without validating them; NewEngine validates the final
// effective configuration after all selected source layers are combined.
// Mapping captures a copy of supported input values at creation; unsupported
// values fail when the source is loaded.
func BackendSource(label string, backends map[string]BackendConfig) configkit.Source {
	definitions := make(map[string]any, len(backends))
	for id, config := range backends {
		fields := make(map[string]any)
		if config.Endpoint != nil {
			fields["endpoint"] = *config.Endpoint
		}
		if config.APIKeyEnv != nil {
			fields["api_key_env"] = *config.APIKeyEnv
		}
		if config.ConcurrencyLimit != nil {
			fields["concurrency_limit"] = *config.ConcurrencyLimit
		}
		if config.QueueCapacity != nil {
			fields["queue_capacity"] = *config.QueueCapacity
		}
		if config.ExtraParams != nil {
			fields["extra_params"] = providerMapForMapping(config.ExtraParams)
		}
		if config.SmokeTests != nil {
			smokeTests := make(map[string]any)
			if config.SmokeTests.DefaultProfile != nil {
				smokeTests["default_profile"] = *config.SmokeTests.DefaultProfile
			}
			if config.SmokeTests.Reachability != nil {
				reachability := make(map[string]any)
				if config.SmokeTests.Reachability.Endpoint != nil {
					reachability["endpoint"] = *config.SmokeTests.Reachability.Endpoint
				}
				smokeTests["reachability"] = reachability
			}
			if config.SmokeTests.Authentication != nil {
				authentication := make(map[string]any)
				if config.SmokeTests.Authentication.Kind != nil {
					authentication["kind"] = *config.SmokeTests.Authentication.Kind
				}
				if config.SmokeTests.Authentication.Endpoint != nil {
					authentication["endpoint"] = *config.SmokeTests.Authentication.Endpoint
				}
				smokeTests["authentication"] = authentication
			}
			fields["smoke_tests"] = smokeTests
		}
		definitions[id] = fields
	}
	return configkit.Mapping(label, map[string]any{"backends": definitions})
}

// LocalBackend supplies endpoint and concurrency pointers for a caller-chosen
// backend ID; it does not select an ID or validate either value.
func LocalBackend(endpoint string, concurrencyLimit int) BackendConfig {
	return BackendConfig{Endpoint: &endpoint, ConcurrencyLimit: &concurrencyLimit}
}