package main

import (
	"context"
	"encoding/json"
	"fmt"
	"log/slog"
	"regexp"
	"strings"
	"time"

	"github.com/dtoro/oikos/internal/db/sqlcgen"
	"github.com/dtoro/oikos/internal/observability"
	"github.com/google/uuid"
	"github.com/jackc/pgx/v5/pgxpool"
)

const maxToolResultSize = 4096

type store struct {
	pool *pgxpool.Pool
}

func newStore(ctx context.Context, databaseURL string) (*store, error) {
	if databaseURL == "" {
		return nil, nil
	}
	pool, err := pgxpool.New(ctx, databaseURL)
	if err != nil {
		return nil, fmt.Errorf("connect db: %w", err)
	}
	if err := pool.Ping(ctx); err != nil {
		pool.Close()
		return nil, fmt.Errorf("ping db: %w", err)
	}
	return &store{pool: pool}, nil
}

func (s *store) close() {
	if s.pool != nil {
		s.pool.Close()
	}
}

// session is a chat session elevated to a task: goal-structured work with a
// lifecycle status and an outcome (see migration 018 / the task-board plan).
// Outcome/Summary/EntityID are empty until set, hence omitempty.
type session struct {
	ID           string    `json:"id"`
	Title        string    `json:"title"`
	Actor        string    `json:"actor"`
	Goal         string    `json:"goal"`
	Status       string    `json:"status"`
	Outcome      string    `json:"outcome,omitempty"`
	Summary      string    `json:"summary,omitempty"`
	EntityID     string    `json:"entity_id,omitempty"`
	CreatedAt    time.Time `json:"created_at"`
	LastActiveAt time.Time `json:"last_active_at"`
}

type message struct {
	ID        string          `json:"id"`
	SessionID string          `json:"session_id"`
	Role      string          `json:"role"`
	Content   json.RawMessage `json:"content"`
	CreatedAt time.Time       `json:"created_at"`
}

func (s *store) createSession(ctx context.Context, title string) (*session, error) {
	if s == nil {
		return &session{ID: "ephemeral", Title: title, Actor: "agent:nomos", Status: "active"}, nil
	}
	var id string
	err := s.pool.QueryRow(ctx,
		`INSERT INTO agent_sessions (title, actor) VALUES ($1, 'agent:nomos') RETURNING id`,
		title).Scan(&id)
	if err != nil {
		return nil, err
	}
	// Give the task its own entity so knowledge and involved-entity edges hang
	// off the existing relationships graph. Best-effort: a failure here must not
	// block the chat — the session is usable without a graph anchor.
	entityID := s.createTaskEntity(ctx, id, title)
	return &session{ID: id, Title: title, Actor: "agent:nomos", Status: "active",
		EntityID: entityID, CreatedAt: time.Now(), LastActiveAt: time.Now()}, nil
}

// createTaskEntity creates (or reuses) the task:<session-id> entity that
// anchors this task's knowledge and involved-entity relationships, and records
// it on the session. Returns the entity id, or "" on failure — non-fatal, see
// caller. Requires the 'task' entity type (seeds/ontology.yaml).
func (s *store) createTaskEntity(ctx context.Context, sessionID, title string) string {
	entityID, _ := uuid.NewV7()
	slug := "task:" + sessionID
	// name is UNIQUE(type,name) and chat titles collide ("hi" ×6), so key the
	// name on the session id and keep the human title in attributes for display.
	name := "task " + sessionID
	attrs, _ := json.Marshal(map[string]any{"title": title})
	if err := s.pool.QueryRow(ctx, `
		INSERT INTO entities (id, slug, type, name, attributes)
		VALUES ($1, $2, 'task', $3, $4)
		ON CONFLICT (slug) DO UPDATE SET updated_at = now()
		RETURNING id`, entityID, slug, name, string(attrs)).Scan(&entityID); err != nil {
		slog.Warn("nomos: could not create task entity", "session", sessionID, "error", err)
		return ""
	}
	if _, err := s.pool.Exec(ctx,
		`UPDATE agent_sessions SET entity_id = $1 WHERE id = $2`, entityID, sessionID); err != nil {
		slog.Warn("nomos: could not link task entity", "session", sessionID, "error", err)
	}
	return entityID.String()
}

func (s *store) saveMessage(ctx context.Context, sessionID, role string, content json.RawMessage) error {
	if s == nil {
		return nil
	}
	_, err := s.pool.Exec(ctx,
		`INSERT INTO agent_messages (session_id, role, content) VALUES ($1, $2, $3)`,
		sessionID, role, truncateToolResults(content))
	return err
}

// insertMessageReturningID and updateMessage exist for the auto-continuation
// worker's live-progress persistence (see continue.go): rather than saving
// one message only once the whole continuation finishes — which could be
// several minutes of silence in the UI even though frontend polling exists —
// the worker inserts a placeholder immediately and updates the SAME row as
// each tool call completes, so a poller sees individual steps land, not just
// a final rolled-up summary.
func (s *store) insertMessageReturningID(ctx context.Context, sessionID, role string, content json.RawMessage) (uuid.UUID, error) {
	if s == nil {
		return uuid.Nil, nil
	}
	var id uuid.UUID
	err := s.pool.QueryRow(ctx,
		`INSERT INTO agent_messages (session_id, role, content) VALUES ($1, $2, $3) RETURNING id`,
		sessionID, role, truncateToolResults(content)).Scan(&id)
	return id, err
}

func (s *store) updateMessage(ctx context.Context, id uuid.UUID, content json.RawMessage) error {
	if s == nil || id == uuid.Nil {
		return nil
	}
	_, err := s.pool.Exec(ctx,
		`UPDATE agent_messages SET content = $2 WHERE id = $1`,
		id, truncateToolResults(content))
	return err
}

func truncateToolResults(content json.RawMessage) json.RawMessage {
	var m map[string]any
	if err := json.Unmarshal(content, &m); err != nil {
		return content
	}
	toolCalls, ok := m["tool_calls"].([]any)
	if !ok || len(toolCalls) == 0 {
		return content
	}
	changed := false
	for i, raw := range toolCalls {
		tc, ok := raw.(map[string]any)
		if !ok {
			continue
		}
		if result, ok := tc["result"]; ok {
			resultJSON, _ := json.Marshal(result)
			if len(resultJSON) > maxToolResultSize {
				tc["result"] = string(resultJSON[:maxToolResultSize]) + fmt.Sprintf("...truncated (%d bytes total)", len(resultJSON))
				toolCalls[i] = tc
				changed = true
			}
		}
	}
	if !changed {
		return content
	}
	m["tool_calls"] = toolCalls
	out, err := json.Marshal(m)
	if err != nil {
		return content
	}
	return out
}

func (s *store) touchSession(ctx context.Context, id string) {
	if s != nil {
		s.pool.Exec(ctx, `UPDATE agent_sessions SET last_active_at=now() WHERE id=$1`, id)
	}
}

func (s *store) listSessions(ctx context.Context) ([]session, error) {
	if s == nil {
		return nil, nil
	}
	rows, err := s.pool.Query(ctx,
		`SELECT id, title, actor, goal, status, COALESCE(outcome, ''), summary,
		        COALESCE(entity_id::text, ''), created_at, last_active_at
		 FROM agent_sessions ORDER BY last_active_at DESC LIMIT 50`)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var out []session
	for rows.Next() {
		var sess session
		if err := rows.Scan(&sess.ID, &sess.Title, &sess.Actor, &sess.Goal, &sess.Status,
			&sess.Outcome, &sess.Summary, &sess.EntityID, &sess.CreatedAt, &sess.LastActiveAt); err != nil {
			return nil, err
		}
		out = append(out, sess)
	}
	return out, rows.Err()
}

// getMessages returns a session's ENTIRE message history, unbounded — used
// for the UI's own transcript view (GET /sessions/{id}), where the operator
// should be able to see everything a task has done regardless of how long
// it's run. For LLM replay, see getRecentMessages: sending the operator's
// full transcript is fine; sending the model's full transcript on every
// single turn is not (see getRecentMessages's doc comment).
func (s *store) getMessages(ctx context.Context, sessionID string) ([]message, error) {
	if s == nil {
		return nil, nil
	}
	rows, err := s.pool.Query(ctx,
		`SELECT id, session_id, role, content, created_at FROM agent_messages WHERE session_id=$1 ORDER BY created_at ASC`,
		sessionID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var out []message
	for rows.Next() {
		var m message
		if err := rows.Scan(&m.ID, &m.SessionID, &m.Role, &m.Content, &m.CreatedAt); err != nil {
			return nil, err
		}
		out = append(out, m)
	}
	return out, rows.Err()
}

// getRecentMessages returns the most recent `limit` messages for sessionID,
// in chronological order, plus whether older messages exist beyond that
// window. Used specifically for LLM replay (chatWith): without a bound,
// every turn re-sent the ENTIRE session history into the model's context,
// unconditionally growing with every turn — a real, observed-in-production
// cost/latency/eventual-context-limit risk for exactly the long-running,
// heavily-autonomous tasks (many auto-continuation cycles) this system is
// built to run longest. Fetches limit+1 rows to detect "there's more"
// without a separate COUNT query.
func (s *store) getRecentMessages(ctx context.Context, sessionID string, limit int) (msgs []message, truncated bool, err error) {
	if s == nil {
		return nil, false, nil
	}
	rows, qerr := s.pool.Query(ctx,
		`SELECT id, session_id, role, content, created_at FROM agent_messages
		 WHERE session_id=$1 ORDER BY created_at DESC LIMIT $2`,
		sessionID, limit+1)
	if qerr != nil {
		return nil, false, qerr
	}
	defer rows.Close()

	var out []message
	for rows.Next() {
		var m message
		if err := rows.Scan(&m.ID, &m.SessionID, &m.Role, &m.Content, &m.CreatedAt); err != nil {
			return nil, false, err
		}
		out = append(out, m)
	}
	if err := rows.Err(); err != nil {
		return nil, false, err
	}

	truncated = len(out) > limit
	if truncated {
		out = out[:limit]
	}
	// Rows came back newest-first (for the LIMIT to bound the right end);
	// reverse to chronological order for replay.
	for i, j := 0, len(out)-1; i < j; i, j = i+1, j-1 {
		out[i], out[j] = out[j], out[i]
	}
	return out, truncated, nil
}

func (s *store) deleteSession(ctx context.Context, id string) error {
	if s == nil {
		return nil
	}
	// Resolve the task entity so we can clean up its graph edges and events too
	// — otherwise deleting a session orphans its task:<id> entity, its involves/
	// documents relationships, and its task-scoped events.
	var entID uuid.UUID
	s.pool.QueryRow(ctx, `SELECT entity_id FROM agent_sessions WHERE id = $1`, id).Scan(&entID)

	if _, err := s.pool.Exec(ctx, `DELETE FROM agent_messages WHERE session_id = $1`, id); err != nil {
		return err
	}
	// task.status / entity.touched / knowledge.recorded are all correlated by
	// session id.
	s.pool.Exec(ctx, `DELETE FROM events WHERE correlation_id = $1`, id)
	if _, err := s.pool.Exec(ctx, `DELETE FROM agent_sessions WHERE id = $1`, id); err != nil {
		return err
	}
	if entID != uuid.Nil {
		// relationships FK is ON DELETE RESTRICT, so drop the task's edges first.
		s.pool.Exec(ctx, `DELETE FROM relationships WHERE source_id = $1 OR target_id = $1`, entID)
		s.pool.Exec(ctx, `DELETE FROM entities WHERE id = $1`, entID)
	}
	return nil
}

// taskEntityPtr returns the task entity id for a session, or nil — used as the
// entity_id on task-scoped events so they anchor to the task in the graph.
func (s *store) taskEntityPtr(ctx context.Context, sessionID string) *uuid.UUID {
	var id uuid.UUID
	if err := s.pool.QueryRow(ctx,
		`SELECT entity_id FROM agent_sessions WHERE id = $1`, sessionID).Scan(&id); err != nil || id == uuid.Nil {
		return nil
	}
	return &id
}

// setGoal records the task's goal and moves it into planning. Emits goal.set.
func (s *store) setGoal(ctx context.Context, sessionID, goal string) error {
	if s == nil || sessionID == "" || sessionID == "ephemeral" {
		return nil
	}
	if _, err := s.pool.Exec(ctx,
		`UPDATE agent_sessions SET goal = $2, status = 'planning', last_active_at = now() WHERE id = $1`,
		sessionID, goal); err != nil {
		return err
	}
	_ = observability.Event(ctx, sqlcgen.New(s.pool), "goal.set", s.taskEntityPtr(ctx, sessionID),
		"info", "nomos", sessionID, map[string]any{"goal": goal})
	return nil
}

// planStepInput is one step as the agent proposes it.
type planStepInput struct {
	Title      string
	Detail     string
	TargetSlug string
}

// proposePlan sets the task's plan and moves it into executing. Emits
// plan.proposed with the persisted steps (seq + id) so the panel can render
// and later address them by id.
//
// Two modes, chosen by whether any existing step has left 'pending':
//   - Fresh/revise (no step started yet): full replace (delete + insert). This
//     covers the first call, and a genuine re-plan before any work began.
//   - Mid-flight (some step is running/done/failed/…): APPEND the new steps
//     after the current max seq instead of wiping. The model is instructed to
//     propose the whole plan in one call, but nothing stops it from calling
//     propose_plan again per-step as it goes — a destructive replace in that
//     case would erase every already-completed step, leaving the operator
//     seeing only the most recent single step ("1/1") instead of real
//     progress. Appending makes the panel's step history correct regardless
//     of how the model chooses to call the tool.
func (s *store) proposePlan(ctx context.Context, sessionID string, steps []planStepInput) ([]map[string]any, error) {
	if s == nil || sessionID == "" || sessionID == "ephemeral" {
		return nil, nil
	}
	tx, err := s.pool.Begin(ctx)
	if err != nil {
		return nil, err
	}
	defer tx.Rollback(ctx)

	var startSeq int
	var anyStarted bool
	if err := tx.QueryRow(ctx, `
		SELECT COALESCE(max(seq), 0), COALESCE(bool_or(status <> 'pending'), false)
		FROM session_plan_steps WHERE session_id = $1`, sessionID).Scan(&startSeq, &anyStarted); err != nil {
		return nil, err
	}
	if !anyStarted {
		if _, err := tx.Exec(ctx, `DELETE FROM session_plan_steps WHERE session_id = $1`, sessionID); err != nil {
			return nil, err
		}
		startSeq = 0
	}

	out := make([]map[string]any, 0, len(steps))
	for i, st := range steps {
		var targetSlug *string
		if st.TargetSlug != "" {
			targetSlug = &st.TargetSlug
		}
		seq := startSeq + i + 1
		var id uuid.UUID
		if err := tx.QueryRow(ctx, `
			INSERT INTO session_plan_steps (session_id, seq, title, detail, target_slug)
			VALUES ($1, $2, $3, $4, $5) RETURNING id`,
			sessionID, seq, st.Title, st.Detail, targetSlug).Scan(&id); err != nil {
			return nil, err
		}
		out = append(out, map[string]any{
			"id": id.String(), "seq": seq, "title": st.Title,
			"detail": st.Detail, "target_slug": st.TargetSlug,
		})
	}
	if _, err := tx.Exec(ctx,
		`UPDATE agent_sessions SET status = 'executing', last_active_at = now() WHERE id = $1`, sessionID); err != nil {
		return nil, err
	}
	if err := tx.Commit(ctx); err != nil {
		return nil, err
	}
	// Event after commit so subscribers only ever see a persisted plan.
	// appended=true tells the panel to add these steps to its existing list
	// rather than replace it (mirrors the mid-flight append above).
	_ = observability.Event(ctx, sqlcgen.New(s.pool), "plan.proposed", s.taskEntityPtr(ctx, sessionID),
		"info", "nomos", sessionID, map[string]any{"steps": out, "appended": anyStarted})
	return out, nil
}

// updatePlanStep sets a step's status by seq, stamping started_at/finished_at
// and linking an execution if given. Emits plan.step.started (running) or
// plan.step.finished (terminal) so the panel advances live. The execution link
// is also what lets the api auto-close the step when the execution finishes
// (see closePlanStepForExecution).
func (s *store) updatePlanStep(ctx context.Context, sessionID string, seq int, status, execID string) error {
	if s == nil || sessionID == "" || sessionID == "ephemeral" {
		return nil
	}
	stamp := ""
	switch status {
	case "running":
		stamp = ", started_at = COALESCE(started_at, now())"
	case "done", "failed", "skipped", "blocked":
		stamp = ", finished_at = now()"
	}
	var execPtr *uuid.UUID
	if id, err := uuid.Parse(execID); err == nil {
		execPtr = &id
	}
	var stepID uuid.UUID
	var targetSlug *string
	// stamp is a fixed literal from the switch above — never user input.
	if err := s.pool.QueryRow(ctx, `
		UPDATE session_plan_steps
		SET status = $3, execution_id = COALESCE($4, execution_id)`+stamp+`
		WHERE session_id = $1 AND seq = $2
		RETURNING id, target_slug`, sessionID, seq, status, execPtr).Scan(&stepID, &targetSlug); err != nil {
		return err
	}
	// Anchor the event to the step's target entity when it has one, else the task.
	entPtr := s.taskEntityPtr(ctx, sessionID)
	if targetSlug != nil && *targetSlug != "" {
		var tid uuid.UUID
		if s.pool.QueryRow(ctx, `SELECT id FROM entities WHERE slug = $1`, *targetSlug).Scan(&tid) == nil {
			entPtr = &tid
		}
	}
	evType := "plan.step.finished"
	if status == "running" {
		evType = "plan.step.started"
	}
	data := map[string]any{"step_id": stepID.String(), "seq": seq, "status": status}
	if execID != "" {
		data["execution_id"] = execID
	}
	_ = observability.Event(ctx, sqlcgen.New(s.pool), evType, entPtr, "info", "nomos", sessionID, data)
	return nil
}

// completeTask sets a task's terminal state, outcome, and one-line summary,
// mirrors the outcome onto the task entity's attributes (so the board/graph
// show it), and publishes task.status for the live context panel. outcome is
// success|failure|partial; status is derived (failure → failed, else done).
func (s *store) completeTask(ctx context.Context, sessionID, outcome, summary string) error {
	if s == nil || sessionID == "" || sessionID == "ephemeral" {
		return nil
	}
	status := "done"
	if outcome == "failure" {
		status = "failed"
	}
	if _, err := s.pool.Exec(ctx, `
		UPDATE agent_sessions SET status = $2, outcome = $3, summary = $4, last_active_at = now()
		WHERE id = $1`, sessionID, status, outcome, summary); err != nil {
		return err
	}
	var entID uuid.UUID
	s.pool.QueryRow(ctx, `SELECT entity_id FROM agent_sessions WHERE id = $1`, sessionID).Scan(&entID)
	var entPtr *uuid.UUID
	if entID != uuid.Nil {
		attrs, _ := json.Marshal(map[string]any{"outcome": outcome, "status": status, "summary": summary})
		s.pool.Exec(ctx, `UPDATE entities SET attributes = attributes || $2::jsonb, updated_at = now() WHERE id = $1`,
			entID, string(attrs))
		entPtr = &entID
	}
	severity := "info"
	if outcome == "failure" {
		severity = "warning"
	}
	_ = observability.Event(ctx, sqlcgen.New(s.pool), "task.status", entPtr, severity, "nomos", sessionID,
		map[string]any{"status": status, "outcome": outcome, "summary": summary})
	return nil
}

// staleGoalSession is a goal-bearing task that's gone idle without reaching
// a terminal state — the idle-sweep worker's work list (fix 2+3 of
// plans/2026-07-11-task-completion-safety-net.md).
type staleGoalSession struct {
	ID               string
	Goal             string
	CompletionNudges int
}

// staleGoalSessions finds sessions that framed themselves as a real task
// (goal != '', so the inline safety net in agent.go intentionally left them
// alone) but have sat non-terminal past idleThreshold. completion_nudges
// tells the caller whether to nudge (0) or give up and auto-close (>=1) —
// see processIdleSweep in continue.go.
func (s *store) staleGoalSessions(ctx context.Context, idleThreshold time.Duration, limit int) []staleGoalSession {
	if s == nil {
		return nil
	}
	rows, err := s.pool.Query(ctx, `
		SELECT id, goal, completion_nudges
		FROM agent_sessions
		WHERE goal <> ''
		  AND status IN ('active', 'planning', 'executing')
		  AND last_active_at < now() - ($1 * interval '1 second')
		ORDER BY last_active_at
		LIMIT $2`, idleThreshold.Seconds(), limit)
	if err != nil {
		return nil
	}
	defer rows.Close()
	var out []staleGoalSession
	for rows.Next() {
		var s staleGoalSession
		if err := rows.Scan(&s.ID, &s.Goal, &s.CompletionNudges); err == nil {
			out = append(out, s)
		}
	}
	return out
}

// bumpCompletionNudge records that the idle sweep nudged a stalled session,
// stamping last_active_at so it isn't picked up again until it's genuinely
// idle again (a fresh nudge shouldn't fire every tick while the model is
// mid-response to the previous one).
func (s *store) bumpCompletionNudge(ctx context.Context, sessionID string) error {
	if s == nil {
		return nil
	}
	_, err := s.pool.Exec(ctx, `
		UPDATE agent_sessions SET completion_nudges = completion_nudges + 1, last_active_at = now()
		WHERE id = $1`, sessionID)
	return err
}

// planStep is a persisted plan step, as returned to the frontend for hydration
// (the panel otherwise only sees steps live via plan.proposed/plan.step.*).
type planStep struct {
	ID          string  `json:"id"`
	Seq         int     `json:"seq"`
	Title       string  `json:"title"`
	Detail      string  `json:"detail"`
	Status      string  `json:"status"`
	ExecutionID *string `json:"execution_id,omitempty"`
	TargetSlug  *string `json:"target_slug,omitempty"`
	StartedAt   *string `json:"started_at,omitempty"`
	FinishedAt  *string `json:"finished_at,omitempty"`
}

// getPlanSteps returns a task's plan in order — REST hydration for the context
// panel when it first opens a task (live events only carry deltas from then on).
func (s *store) getPlanSteps(ctx context.Context, sessionID string) ([]planStep, error) {
	if s == nil {
		return nil, nil
	}
	rows, err := s.pool.Query(ctx, `
		SELECT id::text, seq, title, detail, status,
		       execution_id::text, target_slug,
		       started_at::text, finished_at::text
		FROM session_plan_steps WHERE session_id = $1 ORDER BY seq`, sessionID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var out []planStep
	for rows.Next() {
		var st planStep
		var execID, target, started, finished *string
		if err := rows.Scan(&st.ID, &st.Seq, &st.Title, &st.Detail, &st.Status,
			&execID, &target, &started, &finished); err != nil {
			return nil, err
		}
		st.ExecutionID, st.TargetSlug, st.StartedAt, st.FinishedAt = execID, target, started, finished
		out = append(out, st)
	}
	return out, rows.Err()
}

// sessionQuestion is a persisted question, as returned to the frontend.
type sessionQuestion struct {
	ID         string         `json:"id"`
	Prompt     string         `json:"prompt"`
	Context    map[string]any `json:"context"`
	Status     string         `json:"status"`
	Answer     *string        `json:"answer,omitempty"`
	CreatedAt  string         `json:"created_at"`
	AnsweredAt *string        `json:"answered_at,omitempty"`
}

// getQuestions returns a task's questions (open and answered) newest-first —
// REST hydration for the context panel's pinned question card and history.
func (s *store) getQuestions(ctx context.Context, sessionID string) ([]sessionQuestion, error) {
	if s == nil {
		return nil, nil
	}
	rows, err := s.pool.Query(ctx, `
		SELECT id::text, prompt, context, status, answer, created_at::text, answered_at::text
		FROM session_questions WHERE session_id = $1 ORDER BY created_at DESC`, sessionID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var out []sessionQuestion
	for rows.Next() {
		var q sessionQuestion
		var ctxJSON []byte
		var answer, answeredAt *string
		if err := rows.Scan(&q.ID, &q.Prompt, &ctxJSON, &q.Status, &answer, &q.CreatedAt, &answeredAt); err != nil {
			return nil, err
		}
		json.Unmarshal(ctxJSON, &q.Context)
		q.Answer, q.AnsweredAt = answer, answeredAt
		out = append(out, q)
	}
	return out, rows.Err()
}

// askOperator records a structured decision the agent needs from the operator,
// moves the task to awaiting_input, and emits question.raised so the context
// panel pins it. qctx carries {why, options, entities}. Returns the question id.
func (s *store) askOperator(ctx context.Context, sessionID, prompt string, qctx map[string]any) (string, error) {
	if s == nil || sessionID == "" || sessionID == "ephemeral" {
		return "", nil
	}
	ctxJSON, _ := json.Marshal(qctx)
	var qid uuid.UUID
	if err := s.pool.QueryRow(ctx, `
		INSERT INTO session_questions (session_id, prompt, context) VALUES ($1, $2, $3) RETURNING id`,
		sessionID, prompt, string(ctxJSON)).Scan(&qid); err != nil {
		return "", err
	}
	s.pool.Exec(ctx, `UPDATE agent_sessions SET status = 'awaiting_input', last_active_at = now() WHERE id = $1`, sessionID)
	data := map[string]any{"question_id": qid.String(), "prompt": prompt}
	for k, v := range qctx {
		data[k] = v
	}
	_ = observability.Event(ctx, sqlcgen.New(s.pool), "question.raised", s.taskEntityPtr(ctx, sessionID),
		"warning", "nomos", sessionID, data)
	return qid.String(), nil
}

// openQuestionID returns the id of the session's open question, or "". Used to
// auto-close a pending question when the operator answers via a plain chat reply.
func (s *store) openQuestionID(ctx context.Context, sessionID string) string {
	if s == nil || sessionID == "" || sessionID == "ephemeral" {
		return ""
	}
	var qid string
	s.pool.QueryRow(ctx, `SELECT id::text FROM session_questions
		WHERE session_id = $1 AND status = 'open' ORDER BY created_at DESC LIMIT 1`, sessionID).Scan(&qid)
	return qid
}

// getQuestion returns a question's prompt, answer, and session — used to build
// the resume note when the operator answers via the panel.
func (s *store) getQuestion(ctx context.Context, questionID string) (prompt, answer, sessionID string) {
	if s == nil || questionID == "" {
		return "", "", ""
	}
	qid, err := uuid.Parse(questionID)
	if err != nil {
		return "", "", ""
	}
	s.pool.QueryRow(ctx, `SELECT prompt, COALESCE(answer, ''), session_id::text
		FROM session_questions WHERE id = $1`, qid).Scan(&prompt, &answer, &sessionID)
	return
}

// answerQuestion records the operator's answer, returns the task to executing,
// and emits question.answered. It does NOT itself resume the agent — the caller
// decides: a chat reply IS the resuming turn, while a panel answer triggers a
// continuation.
func (s *store) answerQuestion(ctx context.Context, sessionID, questionID, answer string) error {
	if s == nil || sessionID == "" || sessionID == "ephemeral" || questionID == "" {
		return nil
	}
	qid, err := uuid.Parse(questionID)
	if err != nil {
		return err
	}
	if _, err := s.pool.Exec(ctx, `
		UPDATE session_questions SET status = 'answered', answer = $2, answered_at = now()
		WHERE id = $1 AND status = 'open'`, qid, answer); err != nil {
		return err
	}
	s.pool.Exec(ctx, `UPDATE agent_sessions SET status = 'executing', last_active_at = now() WHERE id = $1`, sessionID)
	_ = observability.Event(ctx, sqlcgen.New(s.pool), "question.answered", s.taskEntityPtr(ctx, sessionID),
		"info", "nomos", sessionID, map[string]any{"question_id": questionID, "answer": answer})
	return nil
}

// knowledgeSlugRe matches a nomos knowledge doc slug (<kind>:nomos/<title>) as
// printed in upsert_knowledge's result text.
var knowledgeSlugRe = regexp.MustCompile(`[a-z]+:nomos/[a-z0-9-]+`)

// linkKnowledgeToTask runs after a successful upsert_knowledge call within a
// task: it links the created knowledge doc to the task entity (documents) so
// get_relations(task) surfaces what the task learned, and publishes
// knowledge.recorded for the live panel. Best-effort. The doc is ALSO linked to
// the entity it's "about" by upsert_knowledge itself — that about-link is the
// retrieval path future tasks use (get_entity_knowledge); this task-link is for
// the task's own outcome/knowledge view.
func (s *store) linkKnowledgeToTask(ctx context.Context, sessionID, resultText string) {
	if s == nil || sessionID == "" || sessionID == "ephemeral" {
		return
	}
	slug := knowledgeSlugRe.FindString(resultText)
	if slug == "" {
		return
	}
	var taskID, docID uuid.UUID
	if err := s.pool.QueryRow(ctx,
		`SELECT entity_id FROM agent_sessions WHERE id = $1`, sessionID).Scan(&taskID); err != nil || taskID == uuid.Nil {
		return
	}
	if err := s.pool.QueryRow(ctx,
		`SELECT id FROM entities WHERE slug = $1`, slug).Scan(&docID); err != nil {
		return
	}
	s.pool.Exec(ctx, `
		INSERT INTO relationships (source_id, target_id, type, attributes, valid_from)
		SELECT $1, $2, 'documents', '{"by":"nomos"}'::jsonb, now()
		WHERE NOT EXISTS (
			SELECT 1 FROM relationships
			WHERE source_id = $1 AND target_id = $2 AND type = 'documents' AND valid_to IS NULL)`,
		docID, taskID)
	_ = observability.Event(ctx, sqlcgen.New(s.pool), "knowledge.recorded", &docID, "info", "nomos", sessionID,
		map[string]any{"slug": slug})
}

func (s *store) updateSessionTitle(ctx context.Context, id, title string) error {
	if s == nil {
		return nil
	}
	_, err := s.pool.Exec(ctx, `UPDATE agent_sessions SET title = $1 WHERE id = $2`, title, id)
	return err
}

// resolveAgentID looks up the UUID of the agent entity (e.g. "agent:nomos").
// Returns uuid.Nil if the store is absent or the slug is unknown.
func (s *store) resolveAgentID(ctx context.Context, slug string) uuid.UUID {
	if s == nil {
		return uuid.Nil
	}
	var id uuid.UUID
	if err := s.pool.QueryRow(ctx, `SELECT id FROM entities WHERE slug = $1`, slug).Scan(&id); err != nil {
		return uuid.Nil
	}
	return id
}

// linkExecution records that a gated execution was initiated by a chat
// session, so the auto-continuation worker can feed its result back to that
// session when it finishes. Idempotent — the same execution may appear in
// several tool results across a turn.
func (s *store) linkExecution(ctx context.Context, execID uuid.UUID, sessionID string) {
	if s == nil || execID == uuid.Nil || sessionID == "" || sessionID == "ephemeral" {
		return
	}
	s.pool.Exec(ctx, `
		INSERT INTO nomos_plan_executions (execution_id, session_id)
		VALUES ($1, $2) ON CONFLICT (execution_id) DO NOTHING`, execID, sessionID)
}

// taskSlugRe matches an entity slug: a lowercase type prefix then colon-
// separated segments (host:hubris, lxc:caddy, check:ping:8cf). Mirrors the
// frontend SessionGraph regex so the panel and the involves-graph agree on
// what counts as an entity reference.
var taskSlugRe = regexp.MustCompile(`[a-z][a-z-]*:[a-z0-9][a-z0-9._/-]*(?::[a-z0-9._/-]+)*`)

// touchExcludedTypes are entity types too noisy to record as task involvement:
// a health question names dozens of check:… slugs, executions/tasks are
// bookkeeping, not things the task "worked on".
var touchExcludedTypes = map[string]bool{"check": true, "execution": true, "task": true}

// recordTouched links the task to every entity referenced in a tool call's
// args (task —involves→ entity) and publishes one entity.touched event per
// entity so the live context panel can pulse it. Best-effort: it never blocks
// or fails the tool call. Only args are inspected — what the agent chose to act
// on — never results, since a single bulk query result would otherwise pull the
// whole fleet into the task's graph.
func (s *store) recordTouched(ctx context.Context, sessionID, toolName string, args map[string]any) {
	if s == nil || sessionID == "" || sessionID == "ephemeral" || len(args) == 0 {
		return
	}
	slugs := map[string]struct{}{}
	collectTaskSlugs(args, slugs)
	if len(slugs) == 0 {
		return
	}
	var taskEntityID uuid.UUID
	if err := s.pool.QueryRow(ctx,
		`SELECT entity_id FROM agent_sessions WHERE id = $1`, sessionID).Scan(&taskEntityID); err != nil || taskEntityID == uuid.Nil {
		return // no task entity to anchor edges on
	}

	// One batched lookup instead of a SELECT per slug — a tool call naming
	// several entities (e.g. a multi-target comparison) used to issue N
	// round-trips here for N slugs found in its args.
	slugList := make([]string, 0, len(slugs))
	for slug := range slugs {
		slugList = append(slugList, slug)
	}
	rows, err := s.pool.Query(ctx,
		`SELECT id, type, slug FROM entities WHERE slug = ANY($1)`, slugList)
	if err != nil {
		return
	}
	type found struct {
		id    uuid.UUID
		etype string
	}
	matched := make(map[string]found, len(slugList))
	for rows.Next() {
		var f found
		var slug string
		if rows.Scan(&f.id, &f.etype, &slug) == nil {
			matched[slug] = f
		}
	}
	rows.Close()
	if err := rows.Err(); err != nil {
		return
	}

	q := sqlcgen.New(s.pool)
	for slug, f := range matched {
		if touchExcludedTypes[f.etype] || f.id == taskEntityID {
			continue
		}
		// Idempotent involves edge (task → entity), same guard as upsert_knowledge.
		s.pool.Exec(ctx, `
			INSERT INTO relationships (source_id, target_id, type, attributes, valid_from)
			SELECT $1, $2, 'involves', '{"by":"nomos"}'::jsonb, now()
			WHERE NOT EXISTS (
				SELECT 1 FROM relationships
				WHERE source_id = $1 AND target_id = $2 AND type = 'involves' AND valid_to IS NULL)`,
			taskEntityID, f.id)
		// Live pulse for the panel. correlation_id = sessionID lets the frontend
		// filter to the active task.
		_ = observability.Event(ctx, q, "entity.touched", &f.id, "info", "nomos", sessionID,
			map[string]any{"slug": slug, "tool": toolName})
	}
}

// collectTaskSlugs recursively pulls entity slugs out of tool-call args,
// mirroring the frontend's collectSlugs so both sides see the same references.
func collectTaskSlugs(v any, out map[string]struct{}) {
	switch t := v.(type) {
	case string:
		for _, m := range taskSlugRe.FindAllString(t, -1) {
			out[strings.TrimRight(m, ".,;)]")] = struct{}{}
		}
	case []any:
		for _, e := range t {
			collectTaskSlugs(e, out)
		}
	case map[string]any:
		for _, e := range t {
			collectTaskSlugs(e, out)
		}
	}
}

// pendingContinuation is one finished execution whose result hasn't yet been
// fed back to its originating session.
type pendingContinuation struct {
	ExecID    uuid.UUID
	SessionID string
	Status    string
	Result    string
	Action    string
}

// pendingContinuations returns executions that have reached a terminal state
// but haven't been continued yet — the worker's work list. Bounded so one
// tick can't fan out unboundedly.
func (s *store) pendingContinuations(ctx context.Context, limit int) []pendingContinuation {
	if s == nil {
		return nil
	}
	rows, err := s.pool.Query(ctx, `
		SELECT l.execution_id, l.session_id, e.status,
		       COALESCE(e.result::text, ''), COALESCE(e.action, '')
		FROM nomos_plan_executions l
		JOIN executions e ON e.entity_id = l.execution_id
		WHERE l.continued_at IS NULL
		  AND e.status IN ('completed', 'failed', 'cancelled', 'denied', 'revoked')
		ORDER BY l.created_at
		LIMIT $1`, limit)
	if err != nil {
		return nil
	}
	defer rows.Close()
	var out []pendingContinuation
	for rows.Next() {
		var p pendingContinuation
		if err := rows.Scan(&p.ExecID, &p.SessionID, &p.Status, &p.Result, &p.Action); err == nil {
			out = append(out, p)
		}
	}
	return out
}

// markContinued stamps an execution as fed-back so the worker won't process it
// again (prevents an auto-continuation loop).
func (s *store) markContinued(ctx context.Context, execID uuid.UUID) {
	if s == nil {
		return
	}
	s.pool.Exec(ctx, `UPDATE nomos_plan_executions SET continued_at = now() WHERE execution_id = $1`, execID)
}

// assentWindowActive reports whether THIS TASK currently has an open assent
// window — the scope gate for auto-continuation. Scoped by session, not just
// agent: with a single agent:nomos entity serving every concurrent task, an
// agent-only key would let approving Task A's plan silently auto-run
// unapproved config-mutation actions in a concurrently-running Task B. We
// only auto-continue executions that are part of THIS session's approved
// plan, never a stray action from another task riding the same window.
func (s *store) assentWindowActive(ctx context.Context, agentID uuid.UUID, sessionID string) bool {
	if s == nil || agentID == uuid.Nil || sessionID == "" {
		return false // fail closed: no session to scope to means no window
	}
	var expires time.Time
	key := assentWindowKey(agentID, sessionID)
	if err := s.pool.QueryRow(ctx, `SELECT value::timestamptz FROM autonomy_settings WHERE key = $1`, key).Scan(&expires); err != nil {
		return false
	}
	return time.Now().Before(expires)
}

// assentWindowKey scopes the grant to one agent AND one session/task — see
// assentWindowActive. Must match internal/mcp/server.go's copy (mirrored
// there, not shared, since the two are separate Go packages/binaries reading
// the same autonomy_settings row).
func assentWindowKey(agentID uuid.UUID, sessionID string) string {
	return "assent_window.agent:" + agentID.String() + ".session:" + sessionID
}

// destructiveWindowDuration is intentionally shorter than the general assent
// window (30 min): it's a narrow, scoped grant for a multi-step DESTRUCTIVE
// recovery (e.g. "stop then destroy this specific half-provisioned
// container"), not a standing license to destroy things.
const destructiveWindowDuration = 15 * time.Minute

// destructiveWindowKey scopes the grant to one agent, one target entity, AND
// one session/task — an explicit typed confirmation ("I confirm") for a
// destructive action on target X in task A must never be read as authorizing
// a destructive action on target X from a DIFFERENT concurrently-running
// task B, even though both share the same agent identity.
func destructiveWindowKey(agentID uuid.UUID, targetSlug, sessionID string) string {
	return "destructive_window.agent:" + agentID.String() + ".target:" + targetSlug + ".session:" + sessionID
}

// openDestructiveWindow records a short, target-and-session-scoped grant
// after an operator's EXPLICIT typed confirmation (never loose assent)
// authorized a destructive action. Real case this exists for: recovering a
// failed destroy took "stop" (destructive) then "destroy" (destructive) —
// same container, two separate typed-confirmation round trips, because each
// was gated independently. One explicit confirmation on a target should
// cover the short follow-up sequence needed to finish what was just
// confirmed — but only within the task that got the confirmation.
func (s *store) openDestructiveWindow(ctx context.Context, agentID uuid.UUID, targetSlug, sessionID string) {
	if s == nil || agentID == uuid.Nil || targetSlug == "" || sessionID == "" {
		return
	}
	expires := time.Now().Add(destructiveWindowDuration).UTC().Format(time.RFC3339)
	s.pool.Exec(ctx, `INSERT INTO autonomy_settings (key, value) VALUES ($1, $2)
		ON CONFLICT (key) DO UPDATE SET value = $2`, destructiveWindowKey(agentID, targetSlug, sessionID), expires)
}

// destructiveWindowActive reports whether target has a live, explicitly-
// confirmed destructive grant for this agent within this session/task.
func (s *store) destructiveWindowActive(ctx context.Context, agentID uuid.UUID, targetSlug, sessionID string) bool {
	if s == nil || agentID == uuid.Nil || targetSlug == "" || sessionID == "" {
		return false
	}
	var expires time.Time
	if err := s.pool.QueryRow(ctx, `SELECT value::timestamptz FROM autonomy_settings WHERE key = $1`,
		destructiveWindowKey(agentID, targetSlug, sessionID)).Scan(&expires); err != nil {
		return false
	}
	return time.Now().Before(expires)
}

// executionTarget resolves the target entity slug for an execution — used to
// scope the destructive window to the right entity when a chat-assent typed
// confirmation grants a destructive execution.
func (s *store) executionTarget(ctx context.Context, execID uuid.UUID) string {
	if s == nil {
		return ""
	}
	var slug string
	s.pool.QueryRow(ctx, `
		SELECT e.slug FROM executions ex JOIN entities e ON e.id = ex.target_entity_id
		WHERE ex.entity_id = $1`, execID).Scan(&slug)
	return slug
}

// logActivity records a tool call. agent_id is the agent entity UUID and is
// NOT NULL in the schema, so we skip logging when it can't be resolved.
// The (nullable) session_id column carries the conversation id.
func (s *store) logActivity(ctx context.Context, agentID uuid.UUID, sessionID, toolName, inputSummary, outputSummary string, durationMs int, success bool, correlationID string) {
	if s == nil || agentID == uuid.Nil {
		return
	}
	s.pool.Exec(ctx, `
		INSERT INTO agent_activity
		    (agent_id, session_id, activity_type, tool_name, input_summary, output_summary,
		     duration_ms, success, correlation_id)
		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)`,
		agentID, sessionID, "tool_call", toolName, inputSummary, outputSummary,
		durationMs, success, correlationID)
}