package db

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

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

	keyVal, err := validateData(table, keyField, data)
	if err != nil {
		return err
	}

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

	var (
		set  []string
		args []any
		i    = 1
	)

	for k, v := range data {
		if k == keyField {
			continue
		}

		set = append(set, fmt.Sprintf("%s=$%d", quoteCol(k), i))
		args = append(args, v)
		i++
	}

	args = append(args, keyVal)

	sql := fmt.Sprintf(
		"UPDATE %s SET %s WHERE %s=$%d",
		quoteTable(table),
		strings.Join(set, ", "),
		quoteCol(keyField),
		i,
	)

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

func (c *Client) BatchUpdate(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 := validateData(table, keyField, first); err != nil {
		return err
	}

	tableSQL := quoteTable(table)
	keySQL := quoteCol(keyField)

	var cols []string
	for k := range first {
		if k != keyField {
			cols = append(cols, k)
		}
	}
	sort.Strings(cols)

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

	// CASE 构建
	for _, col := range cols {
		colSQL := quoteCol(col)

		var caseSQL strings.Builder
		caseSQL.WriteString(fmt.Sprintf("%s = CASE %s ", colSQL, keySQL))

		for _, row := range list {
			row = applyMetaFields(ctx, table, row, false)

			keyVal := row[keyField]
			val := row[col]

			caseSQL.WriteString(fmt.Sprintf(
				"WHEN $%d THEN $%d ",
				argIndex,
				argIndex+1,
			))

			args = append(args, keyVal, val)
			argIndex += 2
		}

		caseSQL.WriteString("END")
		sets = append(sets, caseSQL.String())
	}

	// ⭐修复 IN 写法（关键）
	var inPlaceholders []string
	for _, row := range list {
		inPlaceholders = append(inPlaceholders, fmt.Sprintf("$%d", argIndex))
		args = append(args, row[keyField])
		argIndex++
	}

	sql := fmt.Sprintf(
		"UPDATE %s SET %s WHERE %s IN (%s)",
		tableSQL,
		strings.Join(sets, ", "),
		keySQL,
		strings.Join(inPlaceholders, ", "),
	)

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