package repository

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

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

// FeedSlotWriteInput is create/update payload.
type FeedSlotWriteInput struct {
	Code      string
	Title     string
	SlotKey   string
	Placement string
	Active    bool
}

// ListActiveFeedSlots returns active slots for placement.
func (r *AdminRepo) ListActiveFeedSlots(ctx context.Context, placement string) ([]FeedSlotRow, error) {
	rows, err := r.Pool.Query(ctx, `
		SELECT id, code, title, slot_key, placement, active, system, updated_at
		FROM ops_feed_slots
		WHERE active = true AND placement = $1
		ORDER BY code ASC
		LIMIT 100`, placement)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var out []FeedSlotRow
	for rows.Next() {
		var s FeedSlotRow
		if err := rows.Scan(
			&s.ID, &s.Code, &s.Title, &s.SlotKey, &s.Placement, &s.Active, &s.System, &s.UpdatedAt,
		); err != nil {
			return nil, err
		}
		out = append(out, s)
	}
	return out, rows.Err()
}

// CreateFeedSlotWithAudit inserts and audits.
func (r *AdminRepo) CreateFeedSlotWithAudit(
	ctx context.Context, adminID uuid.UUID, in FeedSlotWriteInput, meta json.RawMessage,
) (*FeedSlotRow, error) {
	tx, err := r.Pool.Begin(ctx)
	if err != nil {
		return nil, err
	}
	defer tx.Rollback(ctx)
	var s FeedSlotRow
	err = tx.QueryRow(ctx, `
		INSERT INTO ops_feed_slots(code, title, slot_key, placement, active, system)
		VALUES ($1,$2,$3,$4,$5,false)
		RETURNING id, code, title, slot_key, placement, active, system, updated_at`,
		in.Code, in.Title, in.SlotKey, in.Placement, in.Active,
	).Scan(&s.ID, &s.Code, &s.Title, &s.SlotKey, &s.Placement, &s.Active, &s.System, &s.UpdatedAt)
	if err != nil {
		return nil, mapFeedSlotWriteErr(err)
	}
	if meta == nil {
		meta = json.RawMessage(`{}`)
	}
	if _, err := tx.Exec(ctx, `
		INSERT INTO admin_audit_logs(admin_id, action, target_type, target_id, meta)
		VALUES ($1,'cms.feed_slot.create','feed_slot',$2,$3)`,
		adminID, s.ID.String(), meta,
	); err != nil {
		return nil, err
	}
	if err := tx.Commit(ctx); err != nil {
		return nil, err
	}
	return &s, nil
}

// UpdateFeedSlotWithAudit updates and audits.
func (r *AdminRepo) UpdateFeedSlotWithAudit(
	ctx context.Context, adminID, id uuid.UUID, in FeedSlotWriteInput, meta json.RawMessage,
) (*FeedSlotRow, error) {
	tx, err := r.Pool.Begin(ctx)
	if err != nil {
		return nil, err
	}
	defer tx.Rollback(ctx)
	var system bool
	var oldCode string
	err = tx.QueryRow(ctx, `SELECT system, code FROM ops_feed_slots WHERE id=$1`, id).Scan(&system, &oldCode)
	if errors.Is(err, pgx.ErrNoRows) {
		return nil, pgx.ErrNoRows
	}
	if err != nil {
		return nil, err
	}
	code := in.Code
	if system {
		code = oldCode
	}
	var s FeedSlotRow
	err = tx.QueryRow(ctx, `
		UPDATE ops_feed_slots
		SET code=$2, title=$3, slot_key=$4, placement=$5, active=$6, updated_at=now()
		WHERE id=$1
		RETURNING id, code, title, slot_key, placement, active, system, updated_at`,
		id, code, in.Title, in.SlotKey, in.Placement, in.Active,
	).Scan(&s.ID, &s.Code, &s.Title, &s.SlotKey, &s.Placement, &s.Active, &s.System, &s.UpdatedAt)
	if err != nil {
		return nil, mapFeedSlotWriteErr(err)
	}
	if meta == nil {
		meta = json.RawMessage(`{}`)
	}
	if _, err := tx.Exec(ctx, `
		INSERT INTO admin_audit_logs(admin_id, action, target_type, target_id, meta)
		VALUES ($1,'cms.feed_slot.update','feed_slot',$2,$3)`,
		adminID, id.String(), meta,
	); err != nil {
		return nil, err
	}
	if err := tx.Commit(ctx); err != nil {
		return nil, err
	}
	return &s, nil
}

func mapFeedSlotWriteErr(err error) error {
	var pgErr *pgconn.PgError
	if errors.As(err, &pgErr) && pgErr.Code == "23505" {
		return errString("feed slot code conflict")
	}
	return err
}

// FeedSlotCodeConflict reports unique violation.
func FeedSlotCodeConflict(err error) bool {
	return err != nil && strings.Contains(err.Error(), "feed slot code conflict")
}