package db

import (
	"allapp-go/pkg/logger"
	"context"
	"fmt"
	"strconv"
	"strings"

	"go.uber.org/zap"
)

func (c *Client) LoadData(
	ctx context.Context,
	viewName string,
	searchCondition string,
	orderBy string,
	searchColumns []string,
	args []any,
) ([]map[string]any, error) {

	selectCols := "*"
	if len(searchColumns) > 0 {
		selectCols = strings.Join(searchColumns, ", ")
	}

	where := ""
	if searchCondition != "" {
		where = " WHERE " + searchCondition
	}

	order := ""
	if orderBy != "" {
		order = " ORDER BY " + orderBy
	}

	sql := fmt.Sprintf(
		"SELECT %s FROM %s%s%s",
		selectCols,
		viewName,
		where,
		order,
	)

	logger.FromCtx(ctx).Info("LoadData",
		zap.String("sql", sql),
		zap.Any("args", args),
	)

	return c.query(ctx, sql, args...)
}

func (c *Client) LoadDataPage(
	ctx context.Context,
	viewName string,
	searchCondition string,
	orderBy string,
	searchColumns []string,
	args []any,
	page int,
	pageSize int,
) ([]map[string]any, int, error) {

	selectCols := "*"
	if len(searchColumns) > 0 {
		selectCols = strings.Join(searchColumns, ", ")
	}

	where := ""
	if searchCondition != "" {
		where = " WHERE " + searchCondition
	}

	// 1. COUNT 查询
	countSQL := fmt.Sprintf("SELECT COUNT(*) FROM %s%s", viewName, where)
	countSQL = convertPlaceholder(countSQL)

	var total int
	err := c.pool.QueryRow(ctx, countSQL, args...).Scan(&total)
	if err != nil {
		return nil, 0, err
	}

	// 2. 分页数据查询
	order := ""
	if orderBy != "" {
		order = " ORDER BY " + orderBy
	}

	offset := (page - 1) * pageSize
	dataSQL := fmt.Sprintf(
		"SELECT %s FROM %s%s%s LIMIT %d OFFSET %d",
		selectCols,
		viewName,
		where,
		order,
		pageSize,
		offset,
	)

	logger.FromCtx(ctx).Info("LoadDataPage",
		zap.String("countSQL", countSQL),
		zap.String("dataSQL", dataSQL),
		zap.Any("args", args),
		zap.Int("total", total),
	)

	rows, err := c.query(ctx, dataSQL, args...)
	if err != nil {
		return nil, 0, err
	}

	return rows, total, nil
}

func (c *Client) LoadDataBySQL(
	ctx context.Context,
	sql string,
	args []any,
) ([]map[string]any, error) {

	logger.FromCtx(ctx).Info("LoadDataBySQL",
		zap.String("sql", sql),
		zap.Any("args", args),
	)

	return c.query(ctx, sql, args...)
}

func (c *Client) query(ctx context.Context, sql string, args ...any) ([]map[string]any, error) {

	sql = convertPlaceholder(sql)

	rows, err := c.pool.Query(ctx, sql, args...)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	fields := rows.FieldDescriptions()

	result := make([]map[string]any, 0, 16)

	for rows.Next() {
		values, err := rows.Values()
		if err != nil {
			return nil, err
		}

		row := make(map[string]any, len(values))

		for i := range fields {
			if i < len(values) {
				row[string(fields[i].Name)] = values[i]
			}
		}

		result = append(result, row)
	}

	if err := rows.Err(); err != nil {
		return nil, err
	}

	return result, nil
}

func convertPlaceholder(sql string) string {
	var sb strings.Builder
	sb.Grow(len(sql))

	argIndex := 1

	for i := 0; i < len(sql); i++ {
		if sql[i] == '?' {
			sb.WriteByte('$')
			sb.WriteString(strconv.Itoa(argIndex))
			argIndex++
		} else {
			sb.WriteByte(sql[i])
		}
	}

	return sb.String()
}