package main

import (
	"fmt"
	_ "github.com/go-sql-driver/mysql"
	"log"
	"net/http"
)

const DEBUG = true

func main() {
	err := setup()
	defer teardown()
	if err == nil {
		startServer()
	}
}

func setup() error {
	err := InitDb()
	if err != nil {
		return err
	}
	return nil
}

func teardown() {
	CloseDb()
}

func startServer() {
	port := "8001"
	MainRouter.setGet("/", showCharts)
	MainRouter.setGet("/data/", sendData)
	MainRouter.setPost("/", saveSnapshot)
	fmt.Printf("Listening on port %s...\n", port)
	log.Fatal(http.ListenAndServe(":" + port, nil))
}

func showCharts(w http.ResponseWriter, r *http.Request) error {
	_, err := fmt.Fprint(w, "<h1>Climate Stuff</h1><div>The data will show up here at some stage...</div>")
	return err
}

func sendData(w http.ResponseWriter, r *http.Request) error {
	records, err := getSnapshotRecordsFromDb(50)
	if err != nil {
		return fmt.Errorf("couldn't read rows from the database: %w", err)
	}
	json, err := createJsonFromSnapshotRecords(records)
	if err != nil {
		return fmt.Errorf("couldn't create a json from the records: %w", err)
	}
	w.Header().Set("Content-Type", "application/json")
	_, err = fmt.Fprintf(w, string(json))
	return err
}

func saveSnapshot(w http.ResponseWriter, r *http.Request) error {
	snapshotSub, err := createSnapshotSubFromJsonBodyStream(r.Body)
	if err != nil {
		return fmt.Errorf("couldn't create snapshot from JSON: %w", err)
	}
	err = writeSnapshotToDb(snapshotSub)
	if err != nil {
		return fmt.Errorf("couldn't submit snapshot into the database: %w", err)
	}
	return nil
}