package admin

import (
	"context"
	"encoding/json"
	"errors"

	"github.com/google/uuid"
	"github.com/jackc/pgx/v5"

	"github.com/yuxingu/digital-psychology/apps/api/internal/repository"
)

// AskSessionDetail is AskSessionView plus messages (transcript).
type AskSessionDetail struct {
	repository.AskSessionView
	Messages []repository.AskMessageView `json:"messages"`
}

var ErrAskThreadNotFound = errString("ask thread not found")

// ListAskSessions lists AskSessionView rows.
func (s *Service) ListAskSessions(ctx context.Context, userID *uuid.UUID, limit, offset int) ([]repository.AskSessionView, error) {
	items, err := s.Repo.ListAskSessions(ctx, userID, limit, offset)
	if err != nil {
		return nil, err
	}
	if items == nil {
		items = []repository.AskSessionView{}
	}
	return items, nil
}

// GetAskSessionMeta loads thread meta without message bodies.
func (s *Service) GetAskSessionMeta(ctx context.Context, threadID uuid.UUID) (*repository.AskSessionView, error) {
	view, err := s.Repo.GetAskSession(ctx, threadID)
	if errors.Is(err, pgx.ErrNoRows) {
		return nil, ErrAskThreadNotFound
	}
	if err != nil {
		return nil, err
	}
	return view, nil
}

// GetAskSessionTranscript loads message bodies and audits access.
func (s *Service) GetAskSessionTranscript(ctx context.Context, adminID, threadID uuid.UUID) (*AskSessionDetail, error) {
	view, err := s.Repo.GetAskSession(ctx, threadID)
	if errors.Is(err, pgx.ErrNoRows) {
		return nil, ErrAskThreadNotFound
	}
	if err != nil {
		return nil, err
	}
	msgs, err := s.Repo.ListAskMessagesForAdmin(ctx, threadID)
	if err != nil {
		return nil, err
	}
	if msgs == nil {
		msgs = []repository.AskMessageView{}
	}
	meta, _ := json.Marshal(map[string]any{
		"message_count": len(msgs),
		"user_id":       view.UserID.String(),
	})
	_ = s.Repo.InsertAudit(ctx, adminID, "ask.transcript.read", "ask_thread", threadID.String(), meta)
	return &AskSessionDetail{AskSessionView: *view, Messages: msgs}, nil
}