package node

import (
	"fmt"
	"strings"

	"google.golang.org/protobuf/types/known/structpb"

	"iop/packages/go/config"
	iop "iop/proto/gen/iop"
)

// BuildConfigPayload converts a NodeRecord's adapter config to the proto payload
// sent to node during registration.
//
// Provider-first entries in rec.Providers are compiled first: each provider id
// becomes the adapter instance key. Legacy adapter instances in rec.Adapters are
// appended afterwards. An instance key that appears in both produces an error.
// Providers with a non-empty Adapter field and no protocol profile reference a
// legacy instance and are skipped during provider-first compile. A profile-
// backed provider is compiled under its provider id from the referenced HTTP
// adapter while the legacy instance is retained below.
//
// After config normalisation, OllamaInstances, VllmInstances, and
// OpenAICompatInstances already contain the promoted legacy single-instance
// entries, so only the slice fields are iterated here. Duplicate instance names
// produce an error.
//
// Mock adapter is only included when rec.Adapters.Mock.Enabled is true.
func BuildConfigPayload(rec *NodeRecord) (*iop.NodeConfigPayload, error) {
	payload := &iop.NodeConfigPayload{
		Runtime: &iop.NodeRuntimeConfig{
			Concurrency: int32(rec.Runtime.Concurrency),
		},
	}

	// Conditional mock adapter: only when explicitly enabled in config.
	if rec.Adapters.Mock.Enabled {
		payload.Adapters = append(payload.Adapters, &iop.AdapterConfig{
			Type:    "mock",
			Enabled: true,
			Config:  &iop.AdapterConfig_Mock{Mock: &iop.MockAdapterConfig{}},
		})
	}

	// flat namespace to detect conflicts between provider ids and legacy adapter keys
	seenFlat := make(map[string]struct{})

	for _, p := range rec.Providers {
		if p.Adapter != "" && p.RuntimeProfile == nil {
			// references a legacy adapter instance; skip provider-first compile
			continue
		}
		if rec.Adapters.Mock.Enabled && p.ID == "mock" {
			return nil, fmt.Errorf("provider id %q conflicts with explicit mock adapter instance key", p.ID)
		}
		if _, dup := seenFlat[p.ID]; dup {
			return nil, fmt.Errorf("duplicate provider id %q", p.ID)
		}
		seenFlat[p.ID] = struct{}{}
		var ac *iop.AdapterConfig
		var err error
		if p.RuntimeProfile != nil && strings.TrimSpace(p.Adapter) != "" {
			ac, err = profileBackedProviderToAdapterConfig(rec, p)
		} else {
			ac, err = providerToAdapterConfig(p)
		}
		if err != nil {
			return nil, err
		}
		payload.Adapters = append(payload.Adapters, ac)
	}

	seen := make(map[string]struct{})

	for _, inst := range rec.Adapters.OllamaInstances {
		if !inst.Enabled {
			continue
		}
		key := "ollama:" + inst.Name
		if _, dup := seen[key]; dup {
			return nil, fmt.Errorf("duplicate ollama instance name %q", inst.Name)
		}
		seen[key] = struct{}{}
		if _, conflict := seenFlat[inst.Name]; conflict {
			return nil, fmt.Errorf("ollama adapter instance key %q conflicts with provider id", inst.Name)
		}
		payload.Adapters = append(payload.Adapters, &iop.AdapterConfig{
			Type:    "ollama",
			Enabled: true,
			Name:    inst.Name,
			Config: &iop.AdapterConfig_Ollama{
				Ollama: &iop.OllamaAdapterConfig{
					BaseUrl:          inst.BaseURL,
					ContextSize:      int32(inst.ContextSize),
					Capacity:         int32(inst.Capacity),
					MaxQueue:         int32(inst.MaxQueue),
					QueueTimeoutMs:   int32(inst.QueueTimeoutMS),
					RequestTimeoutMs: int32(inst.RequestTimeoutMS),
				},
			},
		})
	}

	for _, inst := range rec.Adapters.VllmInstances {
		if !inst.Enabled {
			continue
		}
		key := "vllm:" + inst.Name
		if _, dup := seen[key]; dup {
			return nil, fmt.Errorf("duplicate vllm instance name %q", inst.Name)
		}
		seen[key] = struct{}{}
		if _, conflict := seenFlat[inst.Name]; conflict {
			return nil, fmt.Errorf("vllm adapter instance key %q conflicts with provider id", inst.Name)
		}
		payload.Adapters = append(payload.Adapters, &iop.AdapterConfig{
			Type:    "vllm",
			Enabled: true,
			Name:    inst.Name,
			Config: &iop.AdapterConfig_Vllm{
				Vllm: &iop.VllmAdapterConfig{
					Endpoint:         inst.Endpoint,
					Capacity:         int32(inst.Capacity),
					MaxQueue:         int32(inst.MaxQueue),
					QueueTimeoutMs:   int32(inst.QueueTimeoutMS),
					RequestTimeoutMs: int32(inst.RequestTimeoutMS),
				},
			},
		})
	}

	for _, inst := range rec.Adapters.OpenAICompatInstances {
		if !inst.Enabled {
			continue
		}
		key := "openai_compat:" + inst.Name
		if _, dup := seen[key]; dup {
			return nil, fmt.Errorf("duplicate openai_compat instance name %q", inst.Name)
		}
		seen[key] = struct{}{}
		if _, conflict := seenFlat[inst.Name]; conflict {
			return nil, fmt.Errorf("openai_compat adapter instance key %q conflicts with provider id", inst.Name)
		}
		payload.Adapters = append(payload.Adapters, &iop.AdapterConfig{
			Type:    "openai_compat",
			Enabled: true,
			Name:    inst.Name,
			Config: &iop.AdapterConfig_OpenaiCompat{
				OpenaiCompat: &iop.OpenAICompatAdapterConfig{
					Provider:         inst.Provider,
					Endpoint:         inst.Endpoint,
					Headers:          inst.Headers,
					Capacity:         int32(inst.Capacity),
					MaxQueue:         int32(inst.MaxQueue),
					QueueTimeoutMs:   int32(inst.QueueTimeoutMS),
					RequestTimeoutMs: int32(inst.RequestTimeoutMS),
				},
			},
		})
	}

	if rec.Adapters.CLI.Enabled {
		if _, conflict := seenFlat["cli"]; conflict {
			return nil, fmt.Errorf("cli adapter instance key %q conflicts with provider id", "cli")
		}
		profiles := make(map[string]*iop.CLIProfileConfig, len(rec.Adapters.CLI.Profiles))
		for name, p := range rec.Adapters.CLI.Profiles {
			profiles[name] = cliProfileToProto(p)
		}
		payload.Adapters = append(payload.Adapters, &iop.AdapterConfig{
			Type:    "cli",
			Enabled: true,
			Config: &iop.AdapterConfig_Cli{
				Cli: &iop.CLIAdapterConfig{Profiles: profiles},
			},
		})
	}
	return payload, nil
}

type profileBackingAdapter struct {
	provider         string
	endpoint         string
	headers          map[string]string
	capacity         int
	maxQueue         int
	queueTimeoutMS   int
	requestTimeoutMS int
}

func resolveProfileBackingAdapter(rec *NodeRecord, providerID, ref string) (profileBackingAdapter, error) {
	ref = strings.TrimSpace(ref)
	type match struct {
		enabled bool
		backing profileBackingAdapter
		typ     string
	}
	var exact []match
	for _, inst := range rec.Adapters.VllmInstances {
		if inst.Name == ref {
			exact = append(exact, match{inst.Enabled, profileBackingAdapter{
				provider: "vllm", endpoint: inst.Endpoint, capacity: inst.Capacity,
				maxQueue: inst.MaxQueue, queueTimeoutMS: inst.QueueTimeoutMS, requestTimeoutMS: inst.RequestTimeoutMS,
			}, "vllm"})
		}
	}
	for _, inst := range rec.Adapters.OpenAICompatInstances {
		if inst.Name == ref {
			exact = append(exact, match{inst.Enabled, profileBackingAdapter{
				provider: inst.Provider, endpoint: inst.Endpoint, headers: cloneHeaders(inst.Headers), capacity: inst.Capacity,
				maxQueue: inst.MaxQueue, queueTimeoutMS: inst.QueueTimeoutMS, requestTimeoutMS: inst.RequestTimeoutMS,
			}, "openai_compat"})
		}
	}
	if len(exact) > 1 {
		return profileBackingAdapter{}, fmt.Errorf("provider %q adapter %q: backing adapter reference is ambiguous", providerID, ref)
	}
	if len(exact) == 1 {
		if !exact[0].enabled {
			return profileBackingAdapter{}, fmt.Errorf("provider %q adapter %q: backing %s adapter is disabled", providerID, ref, exact[0].typ)
		}
		return exact[0].backing, nil
	}

	var enabled []profileBackingAdapter
	disabled := 0
	switch ref {
	case "vllm":
		for _, inst := range rec.Adapters.VllmInstances {
			if !inst.Enabled {
				disabled++
				continue
			}
			enabled = append(enabled, profileBackingAdapter{
				provider: "vllm", endpoint: inst.Endpoint, capacity: inst.Capacity,
				maxQueue: inst.MaxQueue, queueTimeoutMS: inst.QueueTimeoutMS, requestTimeoutMS: inst.RequestTimeoutMS,
			})
		}
	case "openai_compat":
		for _, inst := range rec.Adapters.OpenAICompatInstances {
			if !inst.Enabled {
				disabled++
				continue
			}
			enabled = append(enabled, profileBackingAdapter{
				provider: inst.Provider, endpoint: inst.Endpoint, headers: cloneHeaders(inst.Headers), capacity: inst.Capacity,
				maxQueue: inst.MaxQueue, queueTimeoutMS: inst.QueueTimeoutMS, requestTimeoutMS: inst.RequestTimeoutMS,
			})
		}
	default:
		return profileBackingAdapter{}, fmt.Errorf("provider %q adapter %q: backing adapter is missing or unsupported", providerID, ref)
	}
	switch len(enabled) {
	case 1:
		return enabled[0], nil
	case 0:
		if disabled > 0 {
			return profileBackingAdapter{}, fmt.Errorf("provider %q adapter %q: backing adapter has no enabled instance", providerID, ref)
		}
		return profileBackingAdapter{}, fmt.Errorf("provider %q adapter %q: backing adapter is missing", providerID, ref)
	default:
		return profileBackingAdapter{}, fmt.Errorf("provider %q adapter %q: backing adapter is ambiguous (%d enabled instances)", providerID, ref, len(enabled))
	}
}

func profileBackedProviderToAdapterConfig(rec *NodeRecord, p config.NodeProviderConf) (*iop.AdapterConfig, error) {
	backing, err := resolveProfileBackingAdapter(rec, p.ID, p.Adapter)
	if err != nil {
		return nil, err
	}
	provider := backing.provider
	if overlay := openAICompatProviderLabel(p); overlay != "" {
		provider = overlay
	}
	endpoint := backing.endpoint
	if overlay := strings.TrimSpace(p.Endpoint); overlay != "" {
		endpoint = overlay
	} else if overlay := strings.TrimSpace(p.BaseURL); overlay != "" {
		endpoint = overlay
	}
	headers := cloneHeaders(backing.headers)
	if p.Headers != nil {
		headers = cloneHeaders(p.Headers)
	}
	capacity := nonZeroOr(p.Capacity, backing.capacity)
	maxQueue := nonZeroOr(p.MaxQueue, backing.maxQueue)
	queueTimeoutMS := nonZeroOr(p.QueueTimeoutMS, backing.queueTimeoutMS)
	requestTimeoutMS := nonZeroOr(p.RequestTimeoutMS, backing.requestTimeoutMS)
	return &iop.AdapterConfig{
		Type: "openai_compat", Enabled: true, Name: p.ID,
		Config: &iop.AdapterConfig_OpenaiCompat{OpenaiCompat: &iop.OpenAICompatAdapterConfig{
			Provider: provider, Endpoint: endpoint, Headers: headers,
			Capacity: int32(capacity), MaxQueue: int32(maxQueue), QueueTimeoutMs: int32(queueTimeoutMS),
			RequestTimeoutMs: int32(requestTimeoutMS), ProtocolProfile: concreteProfileToProto(p.RuntimeProfile),
		}},
	}, nil
}

func nonZeroOr(value, fallback int) int {
	if value != 0 {
		return value
	}
	return fallback
}

func cloneHeaders(headers map[string]string) map[string]string {
	if headers == nil {
		return nil
	}
	cloned := make(map[string]string, len(headers))
	for key, value := range headers {
		cloned[key] = value
	}
	return cloned
}

// providerToAdapterConfig compiles a provider-first NodeProviderConf into an
// AdapterConfig using the provider id as the instance key.
func providerToAdapterConfig(p config.NodeProviderConf) (*iop.AdapterConfig, error) {
	typeName := config.NormalizeProviderType(p.Type)
	switch typeName {
	case "ollama":
		return &iop.AdapterConfig{
			Type:    "ollama",
			Enabled: true,
			Name:    p.ID,
			Config: &iop.AdapterConfig_Ollama{
				Ollama: &iop.OllamaAdapterConfig{
					BaseUrl:          p.BaseURL,
					ContextSize:      int32(p.ContextSize),
					Capacity:         int32(p.Capacity),
					MaxQueue:         int32(p.MaxQueue),
					QueueTimeoutMs:   int32(p.QueueTimeoutMS),
					RequestTimeoutMs: int32(p.RequestTimeoutMS),
				},
			},
		}, nil

	case "openai_compat":
		return &iop.AdapterConfig{
			Type:    "openai_compat",
			Enabled: true,
			Name:    p.ID,
			Config: &iop.AdapterConfig_OpenaiCompat{
				OpenaiCompat: &iop.OpenAICompatAdapterConfig{
					Provider:         openAICompatProviderLabel(p),
					Endpoint:         p.Endpoint,
					Headers:          p.Headers,
					Capacity:         int32(p.Capacity),
					MaxQueue:         int32(p.MaxQueue),
					QueueTimeoutMs:   int32(p.QueueTimeoutMS),
					RequestTimeoutMs: int32(p.RequestTimeoutMS),
					ProtocolProfile:  concreteProfileToProto(p.RuntimeProfile),
				},
			},
		}, nil

	case "cli":
		// provider id becomes both the adapter instance key and the profile key
		return &iop.AdapterConfig{
			Type:    "cli",
			Enabled: true,
			Name:    p.ID,
			Config: &iop.AdapterConfig_Cli{
				Cli: &iop.CLIAdapterConfig{
					Profiles: map[string]*iop.CLIProfileConfig{
						p.ID: {
							Command:      p.Command,
							Args:         append([]string(nil), p.Args...),
							Env:          append([]string(nil), p.Env...),
							Mode:         p.Mode,
							OutputFormat: p.OutputFormat,
							ResumeArgs:   append([]string(nil), p.ResumeArgs...),
						},
					},
				},
			},
		}, nil

	default:
		return nil, fmt.Errorf("provider %q: unsupported type %q for provider-first compile", p.ID, p.Type)
	}
}

func openAICompatProviderLabel(p config.NodeProviderConf) string {
	if provider := strings.TrimSpace(p.Provider); provider != "" {
		return provider
	}
	providerType := strings.ToLower(strings.TrimSpace(p.Type))
	switch providerType {
	case "vllm", "vllm-mlx", "lemonade", "sglang", "openai_api", "seulgivibe_claude", "seulgivibe_openai":
		return providerType
	default:
		return ""
	}
}

// concreteProfileToProto converts a resolved config.ConcreteProtocolProfile
// snapshot to its wire representation. Returns nil when the profile is absent
// so legacy payloads without a profile remain source-compatible.
func concreteProfileToProto(p *config.ConcreteProtocolProfile) *iop.ConcreteProtocolProfile {
	if p == nil {
		return nil
	}
	cp := p.Clone()
	proto := &iop.ConcreteProtocolProfile{
		Id:           cp.ID,
		Driver:       string(cp.Driver),
		BaseUrl:      cp.BaseURL,
		Auth:         &iop.ProtocolAuth{Header: cp.Auth.Header, Scheme: cp.Auth.Scheme},
		Capabilities: append([]string(nil), cp.Capabilities...),
	}
	if len(cp.Operations) > 0 {
		proto.Operations = make(map[string]string, len(cp.Operations))
		for k, v := range cp.Operations {
			proto.Operations[k] = v
		}
	}
	if len(cp.ModelMapping) > 0 {
		proto.ModelMapping = make(map[string]string, len(cp.ModelMapping))
		for k, v := range cp.ModelMapping {
			proto.ModelMapping[k] = v
		}
	}
	if len(cp.Extensions) > 0 {
		if s, err := structpb.NewStruct(cp.Extensions); err == nil {
			proto.Extensions = s
		}
	}
	return proto
}

func cliProfileToProto(p config.CLIProfileConf) *iop.CLIProfileConfig {
	out := &iop.CLIProfileConfig{
		Command:               p.Command,
		Args:                  append([]string(nil), p.Args...),
		Env:                   append([]string(nil), p.Env...),
		Persistent:            p.Persistent,
		Terminal:              p.Terminal,
		ResponseIdleTimeoutMs: int32(p.ResponseIdleTimeoutMS),
		StartupIdleTimeoutMs:  int32(p.StartupIdleTimeoutMS),
		OutputFormat:          p.OutputFormat,
		Mode:                  p.Mode,
		ResumeArgs:            append([]string(nil), p.ResumeArgs...),
	}
	if !p.CompletionMarker.Empty() {
		out.CompletionMarker = &iop.CLICompletionMarker{
			Line:  p.CompletionMarker.Line,
			Regex: p.CompletionMarker.Regex,
		}
	}
	return out
}