package main

import (
	"database/sql"
	"fmt"
	"log"
	"time"

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

// region DB
type DB struct {
	path      string
	readConn  *sql.DB
	writeConn *sql.DB
}

func (db *DB) Open() error {
	if db.path == "" {
		return fmt.Errorf("database path not set")
	}

	writeConn, err := sql.Open("sqlite3", db.path+"?_journal=WAL&_synchronous=NORMAL")
	if err != nil {
		Error.Printf("%++v", err)
		return err
	}
	writeConn.SetMaxOpenConns(1)
	writeConn.SetConnMaxIdleTime(30 * time.Second)
	writeConn.SetConnMaxLifetime(30 * time.Second)
	db.writeConn = writeConn

	readConn, err := sql.Open("sqlite3", db.path+"?mode=ro&_journal=WAL&_synchronous=NORMAL&_mode=ro")
	if err != nil {
		Error.Printf("%++v", err)
		return err
	}
	readConn.SetMaxOpenConns(4)
	readConn.SetConnMaxIdleTime(30 * time.Second)
	readConn.SetConnMaxLifetime(30 * time.Second)
	db.readConn = readConn

	return nil
}

func (db *DB) Close() error {
	err := db.writeConn.Close()
	if err != nil {
		return err
	}

	err = db.readConn.Close()
	if err != nil {
		return err
	}

	return nil
}

type DBCache interface {
	Get(key string) (any, error)
	Set(key string, value any) error
	Tidy() error
	Init() error
}

// region Cache
type Cache struct {
	db     *DB
	hits   int
	misses int
}
type CacheEntry struct {
	Key string
	Value string
	Date time.Time
}

func (cache *Cache) Get(key string) (CacheEntry, error) {
	ret := CacheEntry{}
	var rkey, rvalue string
	var date time.Time
	err := cache.db.readConn.QueryRow("SELECT key, value, date FROM cache WHERE key = ?", key).Scan(&rkey, &rvalue, &date)
	if err != nil {
		log.Printf("Cache miss for %s: %v", key, err)
		cache.misses++
		return ret, err
	}

	ret.Key = rkey
	ret.Value = rvalue
	ret.Date = date
	
	cache.hits++
	log.Printf("Cache hit for %s", key)
	return ret, nil
}

func (cache *Cache) Set(key string, value string) error {
	_, err := cache.db.writeConn.Exec("INSERT INTO cache (key, value) VALUES (?, ?)", key, value)
	if err != nil {
		return err
	}

	return nil
}

func (cache *Cache) Init() error {
	_, err := cache.db.writeConn.Exec("CREATE TABLE IF NOT EXISTS cache (key TEXT, value TEXT, date DATE DEFAULT CURRENT_TIMESTAMP)")
	if err != nil {
		return err
	}

	_, err = cache.db.writeConn.Exec("CREATE INDEX IF NOT EXISTS idx_cache_key ON cache (key)")
	if err != nil {
		return err
	}

	return nil
}

func (cache *Cache) Tidy() error {
	_, err := cache.db.writeConn.Exec("DELETE FROM cache WHERE date < datetime('now', '-1 day')")
	if err != nil {
		return err
	}

	return nil
}

func (cache *Cache) Rate() float32 {
	return float32(cache.hits) / float32(cache.hits+cache.misses)
}
func (cache *Cache) RatePerc() string {
	return fmt.Sprintf("%.2f%%", cache.Rate()*100)
}