// Per-child harness session state (AGENTS.md §7, FR-2, §11 Phase 4).
//
// The Compass fetcher (patchright) keeps a browser storage state — cookies and
// localStorage — so a later scan can reuse the login instead of signing in
// again. That state is a secret: it lives in the database volume only, is never
// exported to git, never logged, and never printed by a command.

package store

import (
	"context"
	"database/sql"
	"fmt"
	"time"
)

// ChildSession is the stored harness session for one child.
type ChildSession struct {
	ChildID   int64
	Child     string
	State     string
	UpdatedAt time.Time
}

// PutSession writes (or refreshes) the harness session state for one child. The
// state is opaque to the store; the fetcher owns its format.
func (s *Store) PutSession(ctx context.Context, childID int64, state string) error {
	if state == "" {
		return fmt.Errorf("put session: state is empty")
	}
	if _, err := s.db.ExecContext(ctx,
		`INSERT INTO session (child_id, state, updated_at) VALUES (?, ?, datetime('now'))
		 ON CONFLICT(child_id) DO UPDATE SET state = excluded.state, updated_at = datetime('now')`,
		childID, state); err != nil {
		return fmt.Errorf("put session for child %d: %w", childID, err)
	}
	return nil
}

// GetSession returns the stored session for one child, or nil when it has none.
func (s *Store) GetSession(ctx context.Context, childID int64) (*ChildSession, error) {
	row := s.db.QueryRowContext(ctx,
		`SELECT se.child_id, COALESCE(ch.name, ''), se.state, se.updated_at
		 FROM session se LEFT JOIN children ch ON ch.id = se.child_id
		 WHERE se.child_id = ?`, childID)
	var cs ChildSession
	var updated string
	if err := row.Scan(&cs.ChildID, &cs.Child, &cs.State, &updated); err != nil {
		if err == sql.ErrNoRows {
			return nil, nil
		}
		return nil, fmt.Errorf("get session for child %d: %w", childID, err)
	}
	cs.UpdatedAt = parseTime(updated)
	return &cs, nil
}

// ListSessions returns the stored sessions, oldest child first. Each state is
// returned in full; callers that print must never print the state.
func (s *Store) ListSessions(ctx context.Context) ([]ChildSession, error) {
	rows, err := s.db.QueryContext(ctx,
		`SELECT se.child_id, COALESCE(ch.name, ''), se.state, se.updated_at
		 FROM session se LEFT JOIN children ch ON ch.id = se.child_id
		 ORDER BY se.child_id`)
	if err != nil {
		return nil, fmt.Errorf("list sessions: %w", err)
	}
	defer rows.Close()

	var out []ChildSession
	for rows.Next() {
		var cs ChildSession
		var updated string
		if err := rows.Scan(&cs.ChildID, &cs.Child, &cs.State, &updated); err != nil {
			return nil, fmt.Errorf("scan session: %w", err)
		}
		cs.UpdatedAt = parseTime(updated)
		out = append(out, cs)
	}
	return out, rows.Err()
}

// DeleteSession removes the stored session for one child. A signed-out or
// rejected login is not a failure; it just means the next scan logs in again.
func (s *Store) DeleteSession(ctx context.Context, childID int64) error {
	if _, err := s.db.ExecContext(ctx, `DELETE FROM session WHERE child_id = ?`, childID); err != nil {
		return fmt.Errorf("delete session for child %d: %w", childID, err)
	}
	return nil
}