Memoh/internal/chat/resolver.go

package chat

import (
	"bufio"
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"log/slog"
	"net/http"
	"strings"
	"time"

	"github.com/jackc/pgx/v5/pgtype"

	"github.com/memohai/memoh/internal/db/sqlc"
	"github.com/memohai/memoh/internal/history"
	"github.com/memohai/memoh/internal/memory"
	"github.com/memohai/memoh/internal/models"
	"github.com/memohai/memoh/internal/schedule"
	"github.com/memohai/memoh/internal/settings"
)

const defaultMaxContextMinutes = 24 * 60

// Resolver orchestrates chat with the agent gateway.
type Resolver struct {
	modelsService   *models.Service
	queries         *sqlc.Queries
	memoryService   *memory.Service
	historyService  *history.Service
	settingsService *settings.Service
	gatewayBaseURL  string
	timeout         time.Duration
	logger          *slog.Logger
	httpClient      *http.Client
	streamingClient *http.Client
}

// NewResolver creates a Resolver that communicates with the agent gateway.
func NewResolver(
	log *slog.Logger,
	modelsService *models.Service,
	queries *sqlc.Queries,
	memoryService *memory.Service,
	historyService *history.Service,
	settingsService *settings.Service,
	gatewayBaseURL string,
	timeout time.Duration,
) *Resolver {
	if strings.TrimSpace(gatewayBaseURL) == "" {
		gatewayBaseURL = "http://127.0.0.1:8081"
	}
	gatewayBaseURL = strings.TrimRight(gatewayBaseURL, "/")
	if timeout <= 0 {
		timeout = 60 * time.Second
	}
	return &Resolver{
		modelsService:   modelsService,
		queries:         queries,
		memoryService:   memoryService,
		historyService:  historyService,
		settingsService: settingsService,
		gatewayBaseURL:  gatewayBaseURL,
		timeout:         timeout,
		logger:          log.With(slog.String("service", "chat")),
		httpClient:      &http.Client{Timeout: timeout},
		streamingClient: &http.Client{},
	}
}

// --- gateway payload ---

type gatewayModelConfig struct {
	ModelID    string   `json:"modelId"`
	ClientType string   `json:"clientType"`
	Input      []string `json:"input"`
	APIKey     string   `json:"apiKey"`
	BaseURL    string   `json:"baseUrl"`
}

type gatewayIdentity struct {
	BotID           string `json:"botId"`
	SessionID       string `json:"sessionId"`
	ContainerID     string `json:"containerId"`
	ContactID       string `json:"contactId"`
	ContactName     string `json:"contactName"`
	ContactAlias    string `json:"contactAlias,omitempty"`
	UserID          string `json:"userId,omitempty"`
	CurrentPlatform string `json:"currentPlatform,omitempty"`
	ReplyTarget     string `json:"replyTarget,omitempty"`
	SessionToken    string `json:"sessionToken,omitempty"`
}

type gatewayRequest struct {
	Model             gatewayModelConfig `json:"model"`
	ActiveContextTime int                `json:"activeContextTime"`
	Channels          []string           `json:"channels"`
	CurrentChannel    string             `json:"currentChannel"`
	AllowedActions    []string           `json:"allowedActions,omitempty"`
	Messages          []ModelMessage     `json:"messages"`
	Skills            []string           `json:"skills"`
	Query             string             `json:"query"`
	Identity          gatewayIdentity    `json:"identity"`
	Attachments       []any              `json:"attachments"`
}

type gatewayResponse struct {
	Messages []ModelMessage `json:"messages"`
	Skills   []string       `json:"skills"`
}

// gatewaySchedule matches the agent gateway ScheduleModel for /chat/trigger-schedule.
type gatewaySchedule struct {
	ID          string `json:"id"`
	Name        string `json:"name"`
	Description string `json:"description"`
	Pattern     string `json:"pattern"`
	MaxCalls    *int   `json:"maxCalls,omitempty"`
	Command     string `json:"command"`
}

// triggerScheduleRequest is the payload for POST /chat/trigger-schedule.
type triggerScheduleRequest struct {
	Model             gatewayModelConfig `json:"model"`
	ActiveContextTime int                `json:"activeContextTime"`
	Channels          []string           `json:"channels"`
	CurrentChannel    string             `json:"currentChannel"`
	AllowedActions    []string           `json:"allowedActions,omitempty"`
	Messages          []ModelMessage     `json:"messages"`
	Skills            []string           `json:"skills"`
	Identity          gatewayIdentity    `json:"identity"`
	Attachments       []any              `json:"attachments"`
	Schedule          gatewaySchedule    `json:"schedule"`
}

// --- resolved context (shared by Chat / StreamChat / TriggerSchedule) ---

type resolvedContext struct {
	payload gatewayRequest
	model   models.GetResponse
	provider sqlc.LlmProvider
}

func (r *Resolver) resolve(ctx context.Context, req ChatRequest) (resolvedContext, error) {
	if strings.TrimSpace(req.Query) == "" {
		return resolvedContext{}, fmt.Errorf("query is required")
	}
	if strings.TrimSpace(req.BotID) == "" {
		return resolvedContext{}, fmt.Errorf("bot id is required")
	}
	if strings.TrimSpace(req.SessionID) == "" {
		return resolvedContext{}, fmt.Errorf("session id is required")
	}

	skipHistory := req.MaxContextLoadTime < 0

	botSettings, err := r.loadBotSettings(ctx, req.BotID)
	if err != nil {
		return resolvedContext{}, err
	}
	userSettings, err := r.loadUserSettings(ctx, req.UserID)
	if err != nil {
		return resolvedContext{}, err
	}
	chatModel, provider, err := r.selectChatModel(ctx, req, botSettings, userSettings)
	if err != nil {
		return resolvedContext{}, err
	}
	clientType, err := normalizeClientType(provider.ClientType)
	if err != nil {
		return resolvedContext{}, err
	}
	maxCtx := coalescePositiveInt(req.MaxContextLoadTime, botSettings.MaxContextLoadTime, defaultMaxContextMinutes)

	var messages []ModelMessage
	var historySkills []string
	if !skipHistory {
		messages, err = r.loadHistoryMessages(ctx, req.BotID, req.SessionID, maxCtx)
		if err != nil {
			return resolvedContext{}, err
		}
		historySkills, err = r.loadHistorySkills(ctx, req.BotID, req.SessionID, maxCtx)
		if err != nil {
			return resolvedContext{}, err
		}
	}
	messages = append(messages, req.Messages...)
	messages = sanitizeMessages(messages)
	skills := dedup(append(historySkills, req.Skills...))
	containerID := r.resolveContainerID(ctx, req.BotID, req.ContainerID)

	payload := gatewayRequest{
		Model: gatewayModelConfig{
			ModelID:    chatModel.ModelID,
			ClientType: clientType,
			Input:      chatModel.Input,
			APIKey:     provider.ApiKey,
			BaseURL:    provider.BaseUrl,
		},
		ActiveContextTime: maxCtx,
		Channels:          nonNilStrings(req.Channels),
		CurrentChannel:    req.CurrentChannel,
		AllowedActions:    req.AllowedActions,
		Messages:          nonNilMessages(messages),
		Skills:            nonNilStrings(skills),
		Query:             req.Query,
		Identity: gatewayIdentity{
			BotID:           req.BotID,
			SessionID:       req.SessionID,
			ContainerID:     containerID,
			ContactID:       firstNonEmpty(req.ContactID, req.UserID, req.BotID),
			ContactName:     firstNonEmpty(req.ContactName, "User"),
			ContactAlias:    req.ContactAlias,
			UserID:          req.UserID,
			CurrentPlatform: req.CurrentChannel,
			ReplyTarget:     req.ReplyTarget,
			SessionToken:    req.SessionToken,
		},
		Attachments: []any{},
	}

	return resolvedContext{payload: payload, model: chatModel, provider: provider}, nil
}

// --- Chat ---

// Chat sends a synchronous chat request to the agent gateway and stores the result.
func (r *Resolver) Chat(ctx context.Context, req ChatRequest) (ChatResponse, error) {
	rc, err := r.resolve(ctx, req)
	if err != nil {
		return ChatResponse{}, err
	}
	resp, err := r.postChat(ctx, rc.payload, req.Token)
	if err != nil {
		return ChatResponse{}, err
	}
	if err := r.storeRound(ctx, req.BotID, req.SessionID, req.Query, resp.Messages, resp.Skills); err != nil {
		return ChatResponse{}, err
	}
	return ChatResponse{
		Messages: resp.Messages,
		Skills:   resp.Skills,
		Model:    rc.model.ModelID,
		Provider: rc.provider.ClientType,
	}, nil
}

// --- TriggerSchedule ---

// TriggerSchedule executes a scheduled command through the agent gateway trigger-schedule endpoint.
func (r *Resolver) TriggerSchedule(ctx context.Context, botID string, payload schedule.TriggerPayload, token string) error {
	if strings.TrimSpace(botID) == "" {
		return fmt.Errorf("bot id is required")
	}
	if strings.TrimSpace(payload.Command) == "" {
		return fmt.Errorf("schedule command is required")
	}

	sessionID := "schedule:" + payload.ID
	req := ChatRequest{
		BotID:     botID,
		SessionID: sessionID,
		Query:     payload.Command,
		UserID:    payload.OwnerUserID,
		Token:     token,
	}
	rc, err := r.resolve(ctx, req)
	if err != nil {
		return err
	}

	triggerReq := triggerScheduleRequest{
		Model:             rc.payload.Model,
		ActiveContextTime: rc.payload.ActiveContextTime,
		Channels:          rc.payload.Channels,
		CurrentChannel:    rc.payload.CurrentChannel,
		AllowedActions:    rc.payload.AllowedActions,
		Messages:          rc.payload.Messages,
		Skills:            rc.payload.Skills,
		Identity: gatewayIdentity{
			BotID:       rc.payload.Identity.BotID,
			SessionID:   rc.payload.Identity.SessionID,
			ContainerID: rc.payload.Identity.ContainerID,
			ContactID:   botID,
			ContactName: "Scheduler",
			UserID:      payload.OwnerUserID,
		},
		Attachments: rc.payload.Attachments,
		Schedule: gatewaySchedule{
			ID:          payload.ID,
			Name:        payload.Name,
			Description: payload.Description,
			Pattern:     payload.Pattern,
			MaxCalls:    payload.MaxCalls,
			Command:     payload.Command,
		},
	}

	resp, err := r.postTriggerSchedule(ctx, triggerReq, token)
	if err != nil {
		return err
	}
	return r.storeRound(ctx, botID, sessionID, payload.Command, resp.Messages, resp.Skills)
}

// --- StreamChat ---

// StreamChat sends a streaming chat request to the agent gateway.
func (r *Resolver) StreamChat(ctx context.Context, req ChatRequest) (<-chan StreamChunk, <-chan error) {
	chunkCh := make(chan StreamChunk)
	errCh := make(chan error, 1)
	r.logger.Info("gateway stream start",
		slog.String("bot_id", req.BotID),
		slog.String("session_id", req.SessionID),
	)

	go func() {
		defer close(chunkCh)
		defer close(errCh)

		rc, err := r.resolve(ctx, req)
		if err != nil {
			r.logger.Error("gateway stream resolve failed",
				slog.String("bot_id", req.BotID),
				slog.String("session_id", req.SessionID),
				slog.Any("error", err),
			)
			errCh <- err
			return
		}
		if err := r.streamChat(ctx, rc.payload, req.BotID, req.SessionID, req.Query, req.Token, chunkCh); err != nil {
			r.logger.Error("gateway stream request failed",
				slog.String("bot_id", req.BotID),
				slog.String("session_id", req.SessionID),
				slog.Any("error", err),
			)
			errCh <- err
		}
	}()
	return chunkCh, errCh
}

// --- HTTP helpers ---

func (r *Resolver) postChat(ctx context.Context, payload gatewayRequest, token string) (gatewayResponse, error) {
	body, err := json.Marshal(payload)
	if err != nil {
		return gatewayResponse{}, err
	}
	url := r.gatewayBaseURL + "/chat/"
	r.logger.Info("gateway request", slog.String("url", url), slog.String("body_prefix", truncate(string(body), 200)))

	httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(body))
	if err != nil {
		return gatewayResponse{}, err
	}
	httpReq.Header.Set("Content-Type", "application/json")
	if strings.TrimSpace(token) != "" {
		httpReq.Header.Set("Authorization", token)
	}

	resp, err := r.httpClient.Do(httpReq)
	if err != nil {
		return gatewayResponse{}, err
	}
	defer resp.Body.Close()

	respBody, err := io.ReadAll(resp.Body)
	if err != nil {
		return gatewayResponse{}, err
	}
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		r.logger.Error("gateway error", slog.String("url", url), slog.Int("status", resp.StatusCode), slog.String("body_prefix", truncate(string(respBody), 300)))
		return gatewayResponse{}, fmt.Errorf("agent gateway error: %s", strings.TrimSpace(string(respBody)))
	}

	var parsed gatewayResponse
	if err := json.Unmarshal(respBody, &parsed); err != nil {
		r.logger.Error("gateway response parse failed", slog.String("body_prefix", truncate(string(respBody), 300)), slog.Any("error", err))
		return gatewayResponse{}, fmt.Errorf("failed to parse gateway response: %w", err)
	}
	return parsed, nil
}

// postTriggerSchedule sends a trigger-schedule request to the agent gateway.
func (r *Resolver) postTriggerSchedule(ctx context.Context, payload triggerScheduleRequest, token string) (gatewayResponse, error) {
	body, err := json.Marshal(payload)
	if err != nil {
		return gatewayResponse{}, err
	}
	url := r.gatewayBaseURL + "/chat/trigger-schedule"
	r.logger.Info("gateway trigger-schedule request", slog.String("url", url), slog.String("schedule_id", payload.Schedule.ID))

	httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(body))
	if err != nil {
		return gatewayResponse{}, err
	}
	httpReq.Header.Set("Content-Type", "application/json")
	if strings.TrimSpace(token) != "" {
		httpReq.Header.Set("Authorization", token)
	}

	resp, err := r.httpClient.Do(httpReq)
	if err != nil {
		return gatewayResponse{}, err
	}
	defer resp.Body.Close()

	respBody, err := io.ReadAll(resp.Body)
	if err != nil {
		return gatewayResponse{}, err
	}
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		r.logger.Error("gateway trigger-schedule error", slog.String("url", url), slog.Int("status", resp.StatusCode), slog.String("body_prefix", truncate(string(respBody), 300)))
		return gatewayResponse{}, fmt.Errorf("agent gateway error: %s", strings.TrimSpace(string(respBody)))
	}

	var parsed gatewayResponse
	if err := json.Unmarshal(respBody, &parsed); err != nil {
		r.logger.Error("gateway trigger-schedule response parse failed", slog.String("body_prefix", truncate(string(respBody), 300)), slog.Any("error", err))
		return gatewayResponse{}, fmt.Errorf("failed to parse gateway response: %w", err)
	}
	return parsed, nil
}

func (r *Resolver) streamChat(ctx context.Context, payload gatewayRequest, botID, sessionID, query, token string, chunkCh chan<- StreamChunk) error {
	body, err := json.Marshal(payload)
	if err != nil {
		return err
	}
	url := r.gatewayBaseURL + "/chat/stream"
	r.logger.Info("gateway stream request", slog.String("url", url), slog.String("body_prefix", truncate(string(body), 200)))
	httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(body))
	if err != nil {
		return err
	}
	httpReq.Header.Set("Content-Type", "application/json")
	httpReq.Header.Set("Accept", "text/event-stream")
	if strings.TrimSpace(token) != "" {
		httpReq.Header.Set("Authorization", token)
	}

	resp, err := r.streamingClient.Do(httpReq)
	if err != nil {
		r.logger.Error("gateway stream connect failed", slog.String("url", url), slog.Any("error", err))
		return err
	}
	defer resp.Body.Close()

	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		errBody, _ := io.ReadAll(resp.Body)
		r.logger.Error("gateway stream error", slog.String("url", url), slog.Int("status", resp.StatusCode), slog.String("body_prefix", truncate(string(errBody), 300)))
		return fmt.Errorf("agent gateway error: %s", strings.TrimSpace(string(errBody)))
	}

	scanner := bufio.NewScanner(resp.Body)
	scanner.Buffer(make([]byte, 0, 64*1024), 2*1024*1024)

	currentEvent := ""
	stored := false
	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		if line == "" {
			continue
		}
		if strings.HasPrefix(line, "event:") {
			currentEvent = strings.TrimSpace(strings.TrimPrefix(line, "event:"))
			continue
		}
		if !strings.HasPrefix(line, "data:") {
			continue
		}
		data := strings.TrimSpace(strings.TrimPrefix(line, "data:"))
		if data == "" || data == "[DONE]" {
			continue
		}
		chunkCh <- StreamChunk([]byte(data))

		if stored {
			continue
		}
		if handled, storeErr := r.tryStoreStream(ctx, botID, sessionID, query, currentEvent, data); storeErr != nil {
			return storeErr
		} else if handled {
			stored = true
		}
	}
	return scanner.Err()
}

// tryStoreStream attempts to extract final messages from a stream event and persist them.
func (r *Resolver) tryStoreStream(ctx context.Context, botID, sessionID, query, eventType, data string) (bool, error) {
	// event: done + data: {messages: [...]}
	if eventType == "done" {
		var resp gatewayResponse
		if err := json.Unmarshal([]byte(data), &resp); err == nil && len(resp.Messages) > 0 {
			return true, r.storeRound(ctx, botID, sessionID, query, resp.Messages, resp.Skills)
		}
	}

	// data: {"type":"agent_end"|"done", ...}
	var envelope struct {
		Type     string          `json:"type"`
		Data     json.RawMessage `json:"data"`
		Messages []ModelMessage  `json:"messages"`
		Skills   []string        `json:"skills"`
	}
	if err := json.Unmarshal([]byte(data), &envelope); err == nil {
		if envelope.Type == "agent_end" && len(envelope.Messages) > 0 {
			return true, r.storeRound(ctx, botID, sessionID, query, envelope.Messages, envelope.Skills)
		}
		if envelope.Type == "done" && len(envelope.Data) > 0 {
			var resp gatewayResponse
			if err := json.Unmarshal(envelope.Data, &resp); err == nil && len(resp.Messages) > 0 {
				return true, r.storeRound(ctx, botID, sessionID, query, resp.Messages, resp.Skills)
			}
		}
	}

	// fallback: data: {messages: [...]}
	var resp gatewayResponse
	if err := json.Unmarshal([]byte(data), &resp); err == nil && len(resp.Messages) > 0 {
		return true, r.storeRound(ctx, botID, sessionID, query, resp.Messages, resp.Skills)
	}
	return false, nil
}

// --- container resolution ---

func (r *Resolver) resolveContainerID(ctx context.Context, botID, explicit string) string {
	if strings.TrimSpace(explicit) != "" {
		return explicit
	}
	if r.queries != nil {
		pgBotID, err := parseUUID(botID)
		if err == nil {
			row, err := r.queries.GetContainerByBotID(ctx, pgBotID)
			if err == nil && strings.TrimSpace(row.ContainerID) != "" {
				return row.ContainerID
			}
		}
	}
	return "mcp-" + botID
}

// --- history helpers ---

func (r *Resolver) loadHistoryMessages(ctx context.Context, botID, sessionID string, maxContextMinutes int) ([]ModelMessage, error) {
	if r.historyService == nil {
		return nil, fmt.Errorf("history service not configured")
	}
	since := time.Now().UTC().Add(-time.Duration(maxContextMinutes) * time.Minute)
	records, err := r.historyService.ListBySessionSince(ctx, botID, sessionID, since)
	if err != nil {
		return nil, err
	}
	var messages []ModelMessage
	for _, record := range records {
		msgs, err := recordToMessages(record)
		if err != nil {
			r.logger.Warn("skip malformed history record", slog.String("record_id", record.ID), slog.Any("error", err))
			continue
		}
		messages = append(messages, msgs...)
	}
	return messages, nil
}

func (r *Resolver) loadHistorySkills(ctx context.Context, botID, sessionID string, maxContextMinutes int) ([]string, error) {
	if r.historyService == nil {
		return nil, fmt.Errorf("history service not configured")
	}
	since := time.Now().UTC().Add(-time.Duration(maxContextMinutes) * time.Minute)
	records, err := r.historyService.ListBySessionSince(ctx, botID, sessionID, since)
	if err != nil {
		return nil, err
	}
	var combined []string
	for _, record := range records {
		combined = append(combined, record.Skills...)
	}
	return dedup(combined), nil
}

// recordToMessages converts a history record (stored as []map[string]any) to typed ModelMessages.
func recordToMessages(record history.Record) ([]ModelMessage, error) {
	if len(record.Messages) == 0 {
		return nil, nil
	}
	raw, err := json.Marshal(record.Messages)
	if err != nil {
		return nil, err
	}
	var msgs []ModelMessage
	if err := json.Unmarshal(raw, &msgs); err != nil {
		return nil, err
	}
	return msgs, nil
}

// --- store helpers ---

func (r *Resolver) storeRound(ctx context.Context, botID, sessionID, query string, messages []ModelMessage, skills []string) error {
	if err := r.storeHistory(ctx, botID, sessionID, query, messages, skills); err != nil {
		return err
	}
	r.storeMemory(ctx, botID, sessionID, query, messages)
	return nil
}

func (r *Resolver) storeHistory(ctx context.Context, botID, sessionID, query string, messages []ModelMessage, skills []string) error {
	if r.historyService == nil {
		return fmt.Errorf("history service not configured")
	}
	if strings.TrimSpace(botID) == "" || strings.TrimSpace(sessionID) == "" {
		return fmt.Errorf("bot id and session id are required")
	}
	if strings.TrimSpace(query) == "" && len(messages) == 0 {
		return nil
	}
	// Convert typed messages to []map[string]any for the history service.
	raw, err := json.Marshal(messages)
	if err != nil {
		return err
	}
	var rows []map[string]any
	if err := json.Unmarshal(raw, &rows); err != nil {
		return err
	}
	_, err = r.historyService.Create(ctx, botID, strings.TrimSpace(sessionID), history.CreateRequest{
		Messages: rows,
		Metadata: map[string]any{"query": strings.TrimSpace(query)},
		Skills:   skills,
	})
	return err
}

func (r *Resolver) storeMemory(ctx context.Context, botID, sessionID, query string, messages []ModelMessage) {
	if r.memoryService == nil {
		return
	}
	if strings.TrimSpace(botID) == "" || strings.TrimSpace(sessionID) == "" {
		return
	}
	memMsgs := make([]memory.Message, 0, len(messages))
	for _, msg := range messages {
		text := strings.TrimSpace(msg.TextContent())
		if text == "" {
			continue
		}
		role := msg.Role
		if strings.TrimSpace(role) == "" {
			role = "assistant"
		}
		memMsgs = append(memMsgs, memory.Message{Role: role, Content: text})
	}
	if len(memMsgs) == 0 {
		return
	}
	if _, err := r.memoryService.Add(ctx, memory.AddRequest{
		Messages:  memMsgs,
		BotID:     botID,
		SessionID: strings.TrimSpace(sessionID),
	}); err != nil {
		r.logger.Warn("store memory failed", slog.Any("error", err))
	}
}

// --- model selection ---

func (r *Resolver) selectChatModel(ctx context.Context, req ChatRequest, botSettings settings.Settings, us resolvedUserSettings) (models.GetResponse, sqlc.LlmProvider, error) {
	if r.modelsService == nil {
		return models.GetResponse{}, sqlc.LlmProvider{}, fmt.Errorf("models service not configured")
	}
	modelID := strings.TrimSpace(req.Model)
	providerFilter := strings.TrimSpace(req.Provider)

	// Priority: request model > bot settings > user settings.
	if modelID == "" && providerFilter == "" {
		if value := strings.TrimSpace(botSettings.ChatModelID); value != "" {
			modelID = value
		} else if value := strings.TrimSpace(us.ChatModelID); value != "" {
			modelID = value
		}
	}

	if modelID == "" {
		return models.GetResponse{}, sqlc.LlmProvider{}, fmt.Errorf("chat model not configured: specify model in request or bot settings")
	}

	if providerFilter == "" {
		return r.fetchChatModel(ctx, modelID)
	}

	candidates, err := r.listCandidates(ctx, providerFilter)
	if err != nil {
		return models.GetResponse{}, sqlc.LlmProvider{}, err
	}
	for _, m := range candidates {
		if m.ModelID == modelID {
			prov, err := models.FetchProviderByID(ctx, r.queries, m.LlmProviderID)
			if err != nil {
				return models.GetResponse{}, sqlc.LlmProvider{}, err
			}
			return m, prov, nil
		}
	}
	return models.GetResponse{}, sqlc.LlmProvider{}, fmt.Errorf("chat model %q not found for provider %q", modelID, providerFilter)
}

func (r *Resolver) fetchChatModel(ctx context.Context, modelID string) (models.GetResponse, sqlc.LlmProvider, error) {
	model, err := r.modelsService.GetByModelID(ctx, modelID)
	if err != nil {
		return models.GetResponse{}, sqlc.LlmProvider{}, err
	}
	if model.Type != models.ModelTypeChat {
		return models.GetResponse{}, sqlc.LlmProvider{}, fmt.Errorf("model is not a chat model")
	}
	prov, err := models.FetchProviderByID(ctx, r.queries, model.LlmProviderID)
	if err != nil {
		return models.GetResponse{}, sqlc.LlmProvider{}, err
	}
	return model, prov, nil
}

func (r *Resolver) listCandidates(ctx context.Context, providerFilter string) ([]models.GetResponse, error) {
	var all []models.GetResponse
	var err error
	if providerFilter != "" {
		all, err = r.modelsService.ListByClientType(ctx, models.ClientType(providerFilter))
	} else {
		all, err = r.modelsService.ListByType(ctx, models.ModelTypeChat)
	}
	if err != nil {
		return nil, err
	}
	filtered := make([]models.GetResponse, 0, len(all))
	for _, m := range all {
		if m.Type == models.ModelTypeChat {
			filtered = append(filtered, m)
		}
	}
	return filtered, nil
}

// --- settings ---

type resolvedUserSettings struct {
	ChatModelID string
}

func (r *Resolver) loadUserSettings(ctx context.Context, userID string) (resolvedUserSettings, error) {
	if r.settingsService == nil || strings.TrimSpace(userID) == "" {
		return resolvedUserSettings{}, nil
	}
	s, err := r.settingsService.Get(ctx, userID)
	if err != nil {
		return resolvedUserSettings{}, err
	}
	return resolvedUserSettings{
		ChatModelID: strings.TrimSpace(s.ChatModelID),
	}, nil
}

func (r *Resolver) loadBotSettings(ctx context.Context, botID string) (settings.Settings, error) {
	if r.settingsService == nil {
		return settings.Settings{
			MaxContextLoadTime: settings.DefaultMaxContextLoadTime,
			Language:           settings.DefaultLanguage,
		}, nil
	}
	return r.settingsService.GetBot(ctx, botID)
}

// --- utility ---

func normalizeClientType(clientType string) (string, error) {
	switch strings.ToLower(strings.TrimSpace(clientType)) {
	case "openai", "openai-compat":
		return "openai", nil
	case "anthropic":
		return "anthropic", nil
	case "google":
		return "google", nil
	default:
		return "", fmt.Errorf("unsupported agent gateway client type: %s", clientType)
	}
}

func sanitizeMessages(messages []ModelMessage) []ModelMessage {
	cleaned := make([]ModelMessage, 0, len(messages))
	for _, msg := range messages {
		if strings.TrimSpace(msg.Role) == "" {
			continue
		}
		if !msg.HasContent() && strings.TrimSpace(msg.ToolCallID) == "" {
			continue
		}
		cleaned = append(cleaned, msg)
	}
	return cleaned
}

func dedup(items []string) []string {
	seen := make(map[string]struct{}, len(items))
	result := make([]string, 0, len(items))
	for _, s := range items {
		trimmed := strings.TrimSpace(s)
		if trimmed == "" {
			continue
		}
		if _, ok := seen[trimmed]; ok {
			continue
		}
		seen[trimmed] = struct{}{}
		result = append(result, trimmed)
	}
	return result
}

func firstNonEmpty(values ...string) string {
	for _, v := range values {
		if strings.TrimSpace(v) != "" {
			return v
		}
	}
	return ""
}

func coalescePositiveInt(values ...int) int {
	for _, v := range values {
		if v > 0 {
			return v
		}
	}
	return defaultMaxContextMinutes
}

func nonNilStrings(s []string) []string {
	if s == nil {
		return []string{}
	}
	return s
}

func nonNilMessages(m []ModelMessage) []ModelMessage {
	if m == nil {
		return []ModelMessage{}
	}
	return m
}

func truncate(s string, n int) string {
	if len(s) <= n {
		return s
	}
	return s[:n] + "..."
}

func parseUUID(id string) (pgtype.UUID, error) {
	trimmed := strings.TrimSpace(id)
	if trimmed == "" {
		return pgtype.UUID{}, fmt.Errorf("empty id")
	}
	var pgID pgtype.UUID
	if err := pgID.Scan(trimmed); err != nil {
		return pgtype.UUID{}, fmt.Errorf("invalid UUID: %w", err)
	}
	return pgID, nil
}