package store

import (
	"context"
	"database/sql"
	"errors"
	"fmt"
	"strings"

	"github.com/google/uuid"
	"github.com/jmoiron/sqlx"

	"git.hangman-lab.top/hzhang/Dialectic.Backend/internal/models"
)

var ErrNotFound = errors.New("not found")

type TopicStore struct {
	db *sqlx.DB
}

func NewTopicStore(db *sqlx.DB) *TopicStore { return &TopicStore{db: db} }

type CreateTopicInput struct {
	Title           string
	Summary         string
	Visibility      models.Visibility
	VerdictSchemaID string
	SignupOpenAt    string // RFC3339; parsed by SQL
	SignupCloseAt   string
	DebateStartAt   string
	DebateEndAt     string
	CreatorUserID   string
}

func (s *TopicStore) Create(ctx context.Context, in CreateTopicInput) (*models.Topic, error) {
	id := uuid.NewString()
	_, err := s.db.ExecContext(ctx, `
		INSERT INTO topics (id, title, summary, visibility, verdict_schema_id,
			signup_open_at, signup_close_at, debate_start_at, debate_end_at, creator_user_id)
		VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
		id, in.Title, in.Summary, in.Visibility, in.VerdictSchemaID,
		in.SignupOpenAt, in.SignupCloseAt, in.DebateStartAt, in.DebateEndAt, in.CreatorUserID)
	if err != nil {
		return nil, fmt.Errorf("insert topic: %w", err)
	}
	return s.GetByID(ctx, id)
}

func (s *TopicStore) GetByID(ctx context.Context, id string) (*models.Topic, error) {
	var t models.Topic
	err := s.db.GetContext(ctx, &t, `SELECT * FROM topics WHERE id = ?`, id)
	if errors.Is(err, sql.ErrNoRows) {
		return nil, ErrNotFound
	}
	if err != nil {
		return nil, err
	}
	return &t, nil
}

type ListFilter struct {
	Status     string // empty = all
	Visibility string // empty = all
	Limit      int    // 0 = default 50
	Offset     int
}

func (s *TopicStore) List(ctx context.Context, f ListFilter) ([]models.Topic, error) {
	if f.Limit <= 0 || f.Limit > 200 {
		f.Limit = 50
	}
	q := "SELECT * FROM topics"
	args := []any{}
	var clauses []string
	if f.Status != "" {
		clauses = append(clauses, "status = ?")
		args = append(args, f.Status)
	}
	if f.Visibility != "" {
		clauses = append(clauses, "visibility = ?")
		args = append(args, f.Visibility)
	}
	if len(clauses) > 0 {
		q += " WHERE " + strings.Join(clauses, " AND ")
	}
	q += " ORDER BY created_at DESC LIMIT ? OFFSET ?"
	args = append(args, f.Limit, f.Offset)

	var rows []models.Topic
	if err := s.db.SelectContext(ctx, &rows, q, args...); err != nil {
		return nil, err
	}
	return rows, nil
}

// SetVisibility flips public/private; records who/when. Returns updated row.
func (s *TopicStore) SetVisibility(ctx context.Context, id string, v models.Visibility, byUserID string) (*models.Topic, error) {
	_, err := s.db.ExecContext(ctx, `
		UPDATE topics SET visibility = ?, visibility_changed_by = ?, visibility_changed_at = CURRENT_TIMESTAMP
		WHERE id = ?`, v, byUserID, id)
	if err != nil {
		return nil, err
	}
	return s.GetByID(ctx, id)
}