package confirmnotice

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

	"hyapp/pkg/appcode"
	"hyapp/pkg/xerr"
)

const (
	deliveryStatusDelivering = "delivering"
	deliveryStatusDelivered  = "delivered"
	deliveryStatusRetryable  = "retryable"
	deliveryStatusFailed     = "failed"
)

// MySQLRepository stores confirm IM delivery state in notice_delivery_events.
type MySQLRepository struct {
	db *sql.DB
}

func NewMySQLRepository(db *sql.DB) *MySQLRepository {
	return &MySQLRepository{db: db}
}

// ClaimConfirmDelivery creates or locks one delivery row; already terminal rows are acknowledged.
func (r *MySQLRepository) ClaimConfirmDelivery(ctx context.Context, workerID string, delivery Delivery, lockTTL time.Duration) (Delivery, bool, error) {
	if r == nil || r.db == nil {
		return Delivery{}, false, xerr.New(xerr.Unavailable, "notice repository is not configured")
	}
	workerID = strings.TrimSpace(workerID)
	if workerID == "" {
		return Delivery{}, false, xerr.New(xerr.InvalidArgument, "worker_id is required")
	}
	if lockTTL <= 0 {
		lockTTL = 30 * time.Second
	}
	delivery.AppCode = appcode.Normalize(delivery.AppCode)
	now := time.Now()
	nowMS := now.UnixMilli()
	lockUntilMS := now.Add(lockTTL).UnixMilli()
	tx, err := r.db.BeginTx(ctx, nil)
	if err != nil {
		return Delivery{}, false, err
	}
	defer tx.Rollback()
	status, retryCount, lockUntil, nextRetry, err := r.lockDelivery(ctx, tx, delivery)
	if errors.Is(err, sql.ErrNoRows) {
		_, err := tx.ExecContext(ctx, `
			INSERT INTO notice_delivery_events (
				source_name, app_code, source_event_id, channel, notice_type, target_user_id,
				status, retry_count, locked_by, lock_until_ms, next_retry_at_ms,
				payload_json, last_error, delivered_at_ms, created_at_ms, updated_at_ms
			) VALUES (?, ?, ?, ?, ?, ?, ?, 0, ?, ?, 0, CAST(? AS JSON), NULL, 0, ?, ?)`,
			sourceMessageActionOutbox, delivery.AppCode, delivery.EventID, delivery.Channel, delivery.NoticeType, delivery.TargetUserID,
			deliveryStatusDelivering, workerID, lockUntilMS, string(delivery.PayloadJSON), nowMS, nowMS,
		)
		if err != nil {
			return Delivery{}, false, err
		}
		if err := tx.Commit(); err != nil {
			return Delivery{}, false, err
		}
		delivery.RetryCount = 0
		return delivery, true, nil
	}
	if err != nil {
		return Delivery{}, false, err
	}
	if status == deliveryStatusDelivered || status == deliveryStatusFailed {
		return Delivery{}, false, tx.Commit()
	}
	if status == deliveryStatusDelivering && lockUntil > nowMS {
		return Delivery{}, false, tx.Commit()
	}
	if status == deliveryStatusRetryable && nextRetry > nowMS {
		return Delivery{}, false, tx.Commit()
	}
	_, err = tx.ExecContext(ctx, `
		UPDATE notice_delivery_events
		SET status = ?, notice_type = ?, target_user_id = ?, retry_count = ?, locked_by = ?,
		    lock_until_ms = ?, next_retry_at_ms = 0, payload_json = CAST(? AS JSON),
		    last_error = NULL, updated_at_ms = ?
		WHERE source_name = ? AND app_code = ? AND source_event_id = ? AND channel = ?`,
		deliveryStatusDelivering, delivery.NoticeType, delivery.TargetUserID, retryCount, workerID,
		lockUntilMS, string(delivery.PayloadJSON), nowMS,
		sourceMessageActionOutbox, delivery.AppCode, delivery.EventID, delivery.Channel,
	)
	if err != nil {
		return Delivery{}, false, err
	}
	if err := tx.Commit(); err != nil {
		return Delivery{}, false, err
	}
	delivery.RetryCount = retryCount
	return delivery, true, nil
}

func (r *MySQLRepository) lockDelivery(ctx context.Context, tx *sql.Tx, delivery Delivery) (string, int, int64, int64, error) {
	var status string
	var retryCount int
	var lockUntil int64
	var nextRetry int64
	err := tx.QueryRowContext(ctx, `
		SELECT status, retry_count, lock_until_ms, next_retry_at_ms
		FROM notice_delivery_events
		WHERE source_name = ? AND app_code = ? AND source_event_id = ? AND channel = ?
		FOR UPDATE`,
		sourceMessageActionOutbox, delivery.AppCode, delivery.EventID, delivery.Channel,
	).Scan(&status, &retryCount, &lockUntil, &nextRetry)
	return status, retryCount, lockUntil, nextRetry, err
}

func (r *MySQLRepository) MarkConfirmDelivered(ctx context.Context, delivery Delivery, deliveredPayload []byte, nowMs int64) error {
	_, err := r.db.ExecContext(ctx, `
		UPDATE notice_delivery_events
		SET status = ?, payload_json = CAST(? AS JSON), last_error = NULL,
		    delivered_at_ms = ?, locked_by = '', lock_until_ms = 0, next_retry_at_ms = 0, updated_at_ms = ?
		WHERE source_name = ? AND app_code = ? AND source_event_id = ? AND channel = ?`,
		deliveryStatusDelivered, string(deliveredPayload), nowMs, nowMs,
		sourceMessageActionOutbox, delivery.AppCode, delivery.EventID, delivery.Channel,
	)
	return err
}

func (r *MySQLRepository) MarkConfirmRetryable(ctx context.Context, delivery Delivery, retryCount int, nextRetryAtMS int64, lastErr string, nowMs int64) error {
	_, err := r.db.ExecContext(ctx, `
		UPDATE notice_delivery_events
		SET status = ?, retry_count = ?, locked_by = '', lock_until_ms = 0,
		    next_retry_at_ms = ?, last_error = ?, updated_at_ms = ?
		WHERE source_name = ? AND app_code = ? AND source_event_id = ? AND channel = ?`,
		deliveryStatusRetryable, retryCount, nextRetryAtMS, truncateError(lastErr), nowMs,
		sourceMessageActionOutbox, delivery.AppCode, delivery.EventID, delivery.Channel,
	)
	return err
}

func (r *MySQLRepository) MarkConfirmFailed(ctx context.Context, delivery Delivery, retryCount int, lastErr string, nowMs int64) error {
	_, err := r.db.ExecContext(ctx, `
		UPDATE notice_delivery_events
		SET status = ?, retry_count = ?, locked_by = '', lock_until_ms = 0,
		    next_retry_at_ms = 0, last_error = ?, updated_at_ms = ?
		WHERE source_name = ? AND app_code = ? AND source_event_id = ? AND channel = ?`,
		deliveryStatusFailed, retryCount, truncateError(lastErr), nowMs,
		sourceMessageActionOutbox, delivery.AppCode, delivery.EventID, delivery.Channel,
	)
	return err
}

func truncateError(message string) string {
	message = strings.TrimSpace(message)
	if len(message) <= 512 {
		return message
	}
	return message[:512]
}