package db

import (
	"context"
	"fmt"
	"sort"
	"strings"
)

func buildInsertSQL(table string, data map[string]any) (string, []any) {
	var (
		cols []string
		vals []string
		args []any
		i    = 1
	)

	for k, v := range data {
		cols = append(cols, quoteCol(k))
		vals = append(vals, fmt.Sprintf("$%d", i))
		args = append(args, v)
		i++
	}

	return fmt.Sprintf(
		"INSERT INTO %s (%s) VALUES (%s)",
		quoteTable(table),
		strings.Join(cols, ", "),
		strings.Join(vals, ", "),
	), args
}

func (c *Client) Insert(ctx context.Context, table, keyField string, data map[string]any) error {
	if _, err := validateInsertData(table, keyField, data); err != nil {
		return err
	}

	ensureID(data, keyField)

	data = applyMetaFields(ctx, table, data, true)

	sql, args := buildInsertSQL(table, data)

	_, err := c.pool.Exec(ctx, sql, args...)
	return err
}

func (c *Client) BatchInsert(ctx context.Context, table, keyField string, list []map[string]any) error {

	if len(list) == 0 {
		return fmt.Errorf("empty data")
	}

	first := list[0]
	if _, err := validateInsertData(table, keyField, first); err != nil {
		return err
	}

	tableSQL := quoteTable(table)

	// 固定字段顺序（稳定性关键）
	var cols []string
	for k := range first {
		cols = append(cols, k)
	}
	sort.Strings(cols)

	var (
		args     []any
		values   []string
		argIndex = 1
	)

	for _, row := range list {
		ensureID(row, keyField)

		row = applyMetaFields(ctx, table, row, true)

		var place []string

		for _, col := range cols {
			v, ok := row[col]
			if !ok {
				return fmt.Errorf("missing field: %s", col)
			}

			place = append(place, fmt.Sprintf("$%d", argIndex))
			args = append(args, v)
			argIndex++
		}

		values = append(values, fmt.Sprintf("(%s)", strings.Join(place, ",")))
	}

	var quotedCols []string
	for _, col := range cols {
		quotedCols = append(quotedCols, quoteCol(col))
	}

	sql := fmt.Sprintf(
		"INSERT INTO %s (%s) VALUES %s",
		tableSQL,
		strings.Join(quotedCols, ", "),
		strings.Join(values, ", "),
	)

	_, err := c.pool.Exec(ctx, sql, args...) // ⭐关键修复
	return err
}