package repository

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

const BusinessEventSucceeded = "成功"

type BusinessEvent struct {
	ID         int64     `json:"id"`
	OccurredAt time.Time `json:"occurred_at"`
	Event      string    `json:"event"`
	Status     string    `json:"status"`
}

func (r *SQLiteUsageRepository) RecordBusinessEvent(ctx context.Context, event, status string, occurredAt time.Time) error {
	return insertBusinessEvent(ctx, r.db, event, status, occurredAt)
}

func (r *SQLiteUsageRepository) ListBusinessEvents(ctx context.Context, limit int) ([]BusinessEvent, error) {
	if limit < 1 || limit > 500 {
		limit = 200
	}
	rows, err := r.readDB.QueryContext(ctx, `
SELECT id, occurred_at, event, status
FROM business_events ORDER BY occurred_at DESC, id DESC LIMIT ?`, limit)
	if err != nil {
		return nil, fmt.Errorf("查询业务日志: %w", err)
	}
	defer rows.Close()
	events := make([]BusinessEvent, 0, limit)
	for rows.Next() {
		var item BusinessEvent
		var occurredRaw string
		if err := rows.Scan(&item.ID, &occurredRaw, &item.Event, &item.Status); err != nil {
			return nil, fmt.Errorf("读取业务日志: %w", err)
		}
		item.OccurredAt, _ = time.Parse(time.RFC3339Nano, occurredRaw)
		events = append(events, item)
	}
	if err := rows.Err(); err != nil {
		return nil, fmt.Errorf("遍历业务日志: %w", err)
	}
	return events, nil
}

type businessEventExecer interface {
	ExecContext(context.Context, string, ...any) (sql.Result, error)
}

func insertBusinessEvent(ctx context.Context, executor businessEventExecer, event, status string, occurredAt time.Time) error {
	event = strings.TrimSpace(event)
	status = strings.TrimSpace(status)
	if event == "" || status == "" {
		return fmt.Errorf("业务日志事件和状态不能为空")
	}
	if occurredAt.IsZero() {
		occurredAt = time.Now().UTC()
	}
	if _, err := executor.ExecContext(ctx, `
INSERT INTO business_events (occurred_at, event, status) VALUES (?, ?, ?)`,
		formatTime(occurredAt), event, status); err != nil {
		return fmt.Errorf("写入业务日志: %w", err)
	}
	return nil
}

func quotedName(value string) string {
	value = strings.TrimSpace(value)
	if value == "" {
		return "未命名用户"
	}
	return "`" + strings.ReplaceAll(value, "`", "") + "`"
}

func decimalMicros(value int64) string {
	prefix := ""
	if value < 0 {
		prefix = "-"
		value = -value
	}
	whole := value / 1_000_000
	fraction := fmt.Sprintf("%06d", value%1_000_000)
	fraction = strings.TrimRight(fraction, "0")
	if fraction == "" {
		return prefix + fmt.Sprintf("%d", whole)
	}
	return prefix + fmt.Sprintf("%d.%s", whole, fraction)
}