package main

import (
	"database/sql"
	"encoding/json"
	"fmt"
	"log"
	"net/http"

	_ "github.com/mattn/go-sqlite3"
)

const (
	PORT    = "8080"
	DB_FILE = "./datefinder.sqlite3"
)

var (
	db *sql.DB
)

func initDatabase() {
	var err error
	db, err = sql.Open("sqlite3", DB_FILE)
	if err != nil {
		log.Fatalf("[!] Could not open database file %s, error: %s\n", DB_FILE, err)
	}

	const query = `
		CREATE TABLE IF NOT EXISTS choices (
			id INTEGER PRIMARY KEY AUTOINCREMENT,
			username TEXT NOT NULL,
			choices TEXT NOT NULL
		);
	`

	_, err = db.Exec(query)
	if err != nil {
		log.Fatalf("[!] Could not create database table, error: %s\n", err)
	}
}

func handleGetPing(w http.ResponseWriter, r *http.Request) {
	log.Printf("[*] Received request %v %v\n", r.Method, r.URL)
	fmt.Fprintf(w, "PONG\n")
}

func handlePostSubmit(w http.ResponseWriter, r *http.Request) {
	log.Printf("[*] Received request %v %v\n", r.Method, r.URL)
	log.Printf("[*] %v\n", r.Body)

	w.Header().Set("Access-Control-Allow-Origin", "*")
	w.Header().Set("Access-Control-Allow-Methods", "OPTIONS, GET, POST")
	w.Header().Set("Access-Control-Allow-Headers", "Content-Type, Access-Control-Allow-Origin")

	var choices [][]bool

	err := json.NewDecoder(r.Body).Decode(&choices)
	if err != nil {
		log.Printf("[!] Error decoding request Body %v, error: %s\n", r.Body, err)
		w.WriteHeader(http.StatusBadRequest)
	}

	choicesJson, err := json.Marshal(choices)
	if err != nil {
		log.Printf("[!] Could not marshal choices, error: %s\n", err)
	}

	const query = `
		INSERT INTO choices (username, choices)
		VALUES (?, ?);
	`

	_, err = db.Exec(query, "DUMMY USERNAME", string(choicesJson))
	if err != nil {
		log.Printf("[!] Could not insert choices into database, error: %s\n", err)
	}

	log.Printf("[*] Persisted choices for %s to database\n", "DUMMY USERNAME")

	w.WriteHeader(http.StatusOK)
}

func handleOptionsSubmit(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Access-Control-Allow-Origin", "*")
	w.Header().Set("Access-Control-Allow-Methods", "OPTIONS, GET, POST")
	w.Header().Set("Access-Control-Allow-Headers", "Content-Type, Access-Control-Allow-Origin")
	w.WriteHeader(http.StatusNoContent)
}

func main() {
	initDatabase()
	defer db.Close()

	http.HandleFunc(
		"GET /api/ping",
		handleGetPing,
	)

	http.HandleFunc(
		"POST /api/submit",
		handlePostSubmit,
	)

	http.HandleFunc(
		"OPTIONS /api/submit",
		handleOptionsSubmit,
	)

	log.Printf("[*] Datefinder server listening on :%s\n", PORT)
	if err := http.ListenAndServe(":8080", nil); err != nil {
		log.Fatalf("[!] Could not start server on %s, error: %s\n", PORT, err)
	}
}