package main

import (
    "database/sql"
    "fmt"
    "io"
    "net/http"

    _ "github.com/go-sql-driver/mysql"
)

var db *sql.DB
var err error

func main() {
    db, err = sql.Open("mysql", "awsuser:mypassword@tcp(mydbinstance1.cahupqyjjqa0.us-east-2.rds.amazonaws.com:3306)/test?charset=utf8")
    check(err)
    defer db.Close()

    err = db.Ping()
    check(err)

    http.HandleFunc("/", index)
    http.HandleFunc("/amigos", amigos)
    http.HandleFunc("/create", create)
    http.HandleFunc("/insert", insert)
    http.HandleFunc("/read", read)
    http.HandleFunc("/update", update)
    http.HandleFunc("/delete", del)
    http.HandleFunc("/drop", drop)
    http.Handle("/favicon.ico", http.NotFoundHandler())
    err := http.ListenAndServe(":8080", nil)
    check(err)
}
func check(err error) {
    if err != nil {
        fmt.Println(err)
    }
}
func index(res http.ResponseWriter, req *http.Request) {
    _, err := io.WriteString(res, "at index")
    check(err)
}
func amigos(res http.ResponseWriter, req *http.Request) {
    rows, err := db.Query(`SELECT aName FROM amigos;`)
    check(err)
    defer rows.Close()

    var s, name string
    s = "RETRIEVED RECORDS:\n"

    for rows.Next() {
        err = rows.Scan(&name)
        check(err)
        s += name + "\n"
    }
    fmt.Fprintln(res, s)
}
func create(res http.ResponseWriter, req *http.Request) {
    stmt, err := db.Prepare(`CREATE TABLE customer (name VARCHAR(20));`)
    check(err)
    defer stmt.Close()

    r, err := stmt.Exec()
    check(err)

    n, err := r.RowsAffected()
    check(err)

    fmt.Fprintln(res, "CREATED TABLE customer", n)
}
func insert(res http.ResponseWriter, req *http.Request) {
    stmt, err := db.Prepare(`INSERT INTO customer VALUES("James");`)
    check(err)
    defer stmt.Close()

    r, err := stmt.Exec()
    check(err)

    n, err := r.RowsAffected()
    check(err)

    fmt.Fprintln(res, "INSERTED RECORD", n)
}
func read(res http.ResponseWriter, req *http.Request) {
    rows, err := db.Query(`SELECT * FROM customer;`)
    check(err)
    defer rows.Close()

    var name string
    for rows.Next() {
        err = rows.Scan(&name)
        check(err)
        fmt.Fprintln(res, "RETRIEVED RECORD:", name)
    }
}
func update(res http.ResponseWriter, req *http.Request) {
    stmt, err := db.Prepare(`UPDATE customer SET name="Jimmy" WHERE name="James";`)
    check(err)
    defer stmt.Close()

    r, err := stmt.Exec()
    check(err)

    n, err := r.RowsAffected()
    check(err)

    fmt.Fprintln(res, "UPDATED RECORD", n)
}
func del(res http.ResponseWriter, req *http.Request) {
    stmt, err := db.Prepare(`DELETE FROM customer WHERE name="Jimmy";`)
    check(err)
    defer stmt.Close()

    r, err := stmt.Exec()
    check(err)

    n, err := r.RowsAffected()
    check(err)

    fmt.Fprintln(res, "DELETED RECORD", n)
}
func drop(res http.ResponseWriter, req *http.Request) {
    stmt, err := db.Prepare(`DROP TABLE customer;`)
    check(err)
    defer stmt.Close()

    _, err = stmt.Exec()
    check(err)

    fmt.Fprintln(res, "DROPPED TABLE customer")
}