package main

/*
Author: Valentijn van der Jagt

In this project i play around with go. This is my first time writing go, and im using a lot of help from sources. all useful sources are listed in the comments below.

*/

// https://stackoverflow.com/questions/61080317/go-lang-very-simple-http-post-requests-and-response-endpoint, HTTP Server example
// https://stackoverflow.com/questions/16466320/is-there-a-way-to-do-repetitive-tasks-at-intervals, How timer intervals work in GoLang
// https://pkg.go.dev/modernc.org/sqlite#section-documentation, how to interface with specifically sqlite in GoLang
// https://github.com/mattn/go-sqlite3/blob/v1.14.34/_example/simple/simple.go,  How to inferface with a database in GoLang.
import (
	"database/sql"
	"log"

	_ "modernc.org/sqlite"
)

func executeQuery(db *sql.DB, query string) {
	_, err := db.Exec(query)
	if err != nil {
		log.Printf("%q: %s\n", err, query)
		return
	}
}

func createTables(db *sql.DB) {
	executeQuery(db, `
		CREATE TABLE shipments (
			id            INTEGER PRIMARY KEY AUTOINCREMENT,
			tracking_number TEXT NOT NULL UNIQUE,
			service       TEXT NOT NULL,
			sender_name   TEXT,
			receiver_name TEXT,
			origin_country  TEXT,
			origin_city     TEXT,
			origin_postal   TEXT,
			origin_address  TEXT,
			destination_country TEXT,
			destination_city    TEXT,
			destination_postal  TEXT,
			destination_address TEXT,
			pickup_date   TEXT,
			estimated_delivery_from TEXT,
			estimated_delivery_to   TEXT,
			current_status TEXT,
			last_update   TEXT DEFAULT (datetime('now')),
			created_at    TEXT DEFAULT (datetime('now'))
		);

		-- Status Events: history of status updates
		CREATE TABLE shipment_events (
			id            INTEGER PRIMARY KEY,
			shipment_id   INTEGER NOT NULL,
			event_time    TEXT NOT NULL,
			status_code   TEXT NOT NULL,
			status_desc   TEXT,
			description   TEXT,
			remark        TEXT,
			next_steps    TEXT,
			location_country TEXT,
			location_city    TEXT,
			location_postal  TEXT,
			FOREIGN KEY (shipment_id) REFERENCES shipments(id)
		);
		CREATE INDEX idx_events_shipment_time ON shipment_events(shipment_id, event_time);

		CREATE TABLE shipment_updates (
			id            INTEGER PRIMARY KEY,
			shipment_id   INTEGER NOT NULL,
			update_time   TEXT DEFAULT (datetime('now')),
			service       TEXT,
			location_country TEXT,
			location_city    TEXT,
			status_code   TEXT,
			status_desc   TEXT,
			estimated_from TEXT,
			estimated_to   TEXT,
			FOREIGN KEY (shipment_id) REFERENCES shipments(id)
		);
		CREATE INDEX idx_updates_shipment_time ON shipment_updates(shipment_id, update_time);
	`)

	log.Printf("[Database] tables created")

}

func dropTables(db *sql.DB) {
	executeQuery(db, `
		DROP TABLE IF EXISTS shipments;
		DROP TABLE IF EXISTS shipment_events;
		DROP TABLE IF EXISTS shipment_updates;
	`)

	log.Printf("[Database] tables dropped")

}

func main() {
	db, err := sql.Open("sqlite", "./dhl.db")
	if err != nil {
		log.Fatal(err)
	}
	defer db.Close()

	dropTables(db) // temporarely for debugging
	createTables(db)
}