package api

import (
    "database/sql"
    "net/http"
    "strconv"
)

type YMTMerchantsAPI struct {
    ymt *sql.DB
}

func YMTMerchantsHandler(ymt *sql.DB) http.Handler {
    api := &YMTMerchantsAPI{ymt: ymt}
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        if r.Method == http.MethodGet {
            api.list(w, r)
            return
        }
        w.WriteHeader(http.StatusNotFound)
    })
}

func (a *YMTMerchantsAPI) list(w http.ResponseWriter, r *http.Request) {
    q := r.URL.Query()
    userIDStr := q.Get("user_id")
    like := q.Get("q")
    limitStr := q.Get("limit")
    limit := 2000
    if limitStr != "" {
        if n, err := strconv.Atoi(limitStr); err == nil && n > 0 && n <= 10000 { limit = n }
    }
    sql1 := "SELECT id, name FROM merchant WHERE id IS NOT NULL"
    args := []interface{}{}
    if userIDStr != "" {
        sql1 += " AND user_id = ?"
        args = append(args, userIDStr)
    }
    if like != "" {
        sql1 += " AND (CAST(id AS CHAR) LIKE ? OR name LIKE ?)"
        s := "%" + like + "%"
        args = append(args, s, s)
    }
    sql1 += " ORDER BY id ASC LIMIT ?"
    args = append(args, limit)
    rows, err := a.ymt.Query(sql1, args...)
    if err != nil {
        fail(w, r, http.StatusInternalServerError, err.Error())
        return
    }
    defer rows.Close()
    out := []map[string]interface{}{}
    for rows.Next() {
        var id sql.NullInt64
        var name sql.NullString
        if err := rows.Scan(&id, &name); err != nil { continue }
        if !id.Valid { continue }
        out = append(out, map[string]interface{}{"id": id.Int64, "name": name.String})
    }
    ok(w, r, out)
}