package main

import (
	"database/sql"
	"fmt"
	"log"
	"net/url"
	"os"

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

var db *sql.DB

func InitDB() {
	host := os.Getenv("DB_HOST")
	port := os.Getenv("DB_PORT")
	name := os.Getenv("DB_DATABASENAME")
	user := os.Getenv("DB_USERNAME")
	pass := os.Getenv("DB_PASSWORD")

	if host == "" {
		log.Println("DB_HOST not set, skipping database initialization")
		return
	}

	// Use TZ env var if set, otherwise fallback to Local
	location := "Local"
	tz := os.Getenv("TZ")

	dsn := fmt.Sprintf("%s:%s@tcp(%s:%s)/%s?parseTime=true&loc=%s", user, pass, host, port, name, location)
	if tz != "" {
		dsn += fmt.Sprintf("&time_zone='%s'", url.QueryEscape(tz))
	}

	var err error
	db, err = sql.Open("mysql", dsn)
	if err != nil {
		log.Fatalf("Error opening database: %v", err)
	}

	if err := db.Ping(); err != nil {
		log.Fatalf("Error connecting to database: %v", err)
	}

	log.Printf("[DB] Connected to MariaDB successfully (using loc=%s, tz=%s)", location, tz)

	createTables()
}

func createTables() {
	queries := []string{
		`CREATE TABLE IF NOT EXISTS users (
			fitbit_user_id VARCHAR(255) PRIMARY KEY,
			display_name VARCHAR(255),
			avatar_url TEXT,
			created_at DATETIME
		)`,
		`CREATE TABLE IF NOT EXISTS sessions (
			token VARCHAR(255) PRIMARY KEY,
			fitbit_user_id VARCHAR(255),
			created_at DATETIME,
			expires_at DATETIME,
			FOREIGN KEY (fitbit_user_id) REFERENCES users(fitbit_user_id) ON DELETE CASCADE
		)`,
		`CREATE TABLE IF NOT EXISTS fitbit_tokens (
			user_id VARCHAR(255) PRIMARY KEY,
			access_token TEXT,
			refresh_token TEXT,
			expires_at DATETIME,
			FOREIGN KEY (user_id) REFERENCES users(fitbit_user_id) ON DELETE CASCADE
		)`,
		`CREATE TABLE IF NOT EXISTS kml_metadata (
			id INT AUTO_INCREMENT PRIMARY KEY,
			filename VARCHAR(255),
			user_id VARCHAR(255),
			distance DOUBLE,
			description TEXT,
			is_public BOOLEAN DEFAULT FALSE,
			uploaded_at DATETIME,
			UNIQUE KEY (user_id, filename),
			FOREIGN KEY (user_id) REFERENCES users(fitbit_user_id) ON DELETE CASCADE
		)`,
		`CREATE TABLE IF NOT EXISTS kml_votes (
			kml_id INT,
			user_id VARCHAR(255),
			vote_value INT,
			PRIMARY KEY (kml_id, user_id),
			FOREIGN KEY (kml_id) REFERENCES kml_metadata(id) ON DELETE CASCADE,
			FOREIGN KEY (user_id) REFERENCES users(fitbit_user_id) ON DELETE CASCADE
		)`,
		`CREATE TABLE IF NOT EXISTS trips (
			user_id VARCHAR(255) PRIMARY KEY,
			start_date VARCHAR(10),
			start_time DATETIME,
			start_day_initial_steps INT,
			previous_total_steps INT,
			target_total_steps INT,
			last_sync_time TIMESTAMP NULL,
			next_sync_time TIMESTAMP NULL,
			FOREIGN KEY (user_id) REFERENCES users(fitbit_user_id) ON DELETE CASCADE
		)`,
		`CREATE TABLE IF NOT EXISTS daily_steps (
			user_id VARCHAR(255),
			date VARCHAR(10),
			steps INT,
			PRIMARY KEY (user_id, date),
			FOREIGN KEY (user_id) REFERENCES users(fitbit_user_id) ON DELETE CASCADE
		)`,
	}

	for _, query := range queries {
		if _, err := db.Exec(query); err != nil {
			log.Fatalf("Error creating table: %v\nQuery: %s", err, query)
		}
	}

	// Migrations: Ensure trips table uses TIMESTAMP for sync times (breaking change for DATETIME -> TIMESTAMP)
	db.Exec("ALTER TABLE trips MODIFY last_sync_time TIMESTAMP NULL")
	db.Exec("ALTER TABLE trips MODIFY next_sync_time TIMESTAMP NULL")
	// Migration for KML description
	db.Exec("ALTER TABLE kml_metadata ADD COLUMN IF NOT EXISTS description TEXT")

	log.Println("Database tables initialized")
}