package server

import (
	"fmt"
	"log/slog"
	"slices"
	"strings"
	"time"

	"git.riou.xyz/jriou/coller/internal"
	"gorm.io/driver/postgres"
	"gorm.io/driver/sqlite"
	"gorm.io/gorm"
	"gorm.io/gorm/logger"
)

type Database struct {
	logger             *slog.Logger
	db                 *gorm.DB
	expirationInterval int
	expirations        []int
	expiration         int
}

var gconfig = &gorm.Config{
	Logger: logger.Default.LogMode(logger.Silent),
}

func NewDatabase(logger *slog.Logger, config *Config) (d *Database, err error) {
	l := logger.With("module", "db")

	logger.Debug("connecting to the database")
	var db *gorm.DB

	switch config.DatabaseType {
	case "postgres":
		db, err = gorm.Open(postgres.New(postgres.Config{DSN: config.DatabaseDsn}), gconfig)
	case "sqlite":
		db, err = gorm.Open(sqlite.Open(config.DatabaseDsn), gconfig)
	default:
		return nil, fmt.Errorf("database type '%s' not supported", config.DatabaseType)
	}
	if err != nil {
		return nil, err
	}

	logger.Debug("connected to the database")

	d = &Database{
		logger:             l,
		db:                 db,
		expirationInterval: config.ExpirationInterval,
		expirations:        config.Expirations,
		expiration:         config.Expiration,
	}

	if err = d.UpdateSchema(); err != nil {
		return nil, err
	}

	go d.StartExpireThread()

	return d, nil
}

func (d *Database) UpdateSchema() error {
	d.logger.Debug("updating database schema")
	if err := d.db.AutoMigrate(&Note{}); err != nil {
		return err
	}
	d.logger.Debug("database schema updated")
	return nil
}

func (d *Database) StartExpireThread() {
	for {
		d.logger.Debug("deleting expired notes")
		trx := d.db.Where("expires_at <= ?", time.Now()).Delete(&Note{})
		if trx.Error != nil {
			d.logger.Error("could not delete note", slog.Any("error", trx.Error))
		}
		d.logger.Debug("expired notes deleted")

		wording := "second"
		if d.expirationInterval > 1 {
			wording += "s"
		}
		d.logger.Debug(fmt.Sprintf("waiting for %d %s before next expiration", d.expirationInterval, wording))
		time.Sleep(time.Duration(d.expirationInterval) * time.Second)
	}
}

func (d *Database) Get(id string) (*Note, error) {
	var note Note
	trx := d.db.Where("id = ?", id).Find(&note)
	if trx.Error != nil {
		d.logger.Warn("could not find note", slog.Any("error", trx.Error))
		return nil, trx.Error
	}
	if note.ID != "" {
		if note.DeleteAfterRead {
			if err := d.Delete(note.ID); err != nil {
				return nil, err
			}
		}
		return &note, nil
	}
	return nil, nil
}

func (d *Database) Create(content []byte, password string, encrypted bool, expiration int, deleteAfterRead bool) (note *Note, err error) {
	if expiration == 0 {
		expiration = d.expiration
	}
	if !slices.Contains(d.expirations, expiration) {
		validExpirations := strings.Trim(strings.Join(strings.Fields(fmt.Sprint(d.expirations)), ", "), "[]")
		return nil, fmt.Errorf("invalid expiration: must be one of %s", validExpirations)
	}

	note = &Note{
		Content:         content,
		ExpiresAt:       time.Now().Add(time.Duration(expiration) * time.Second),
		Encrypted:       encrypted,
		DeleteAfterRead: deleteAfterRead,
	}
	if password != "" {
		if err = internal.ValidatePassword(password); err != nil {
			return nil, err
		}
		note.Content, err = internal.Encrypt(note.Content, password)
		if err != nil {
			return nil, err
		}
		note.Encrypted = true
	}
	trx := d.db.Create(note)
	if trx.Error != nil {
		d.logger.Warn("could not create note", slog.Any("error", trx.Error))
		return nil, trx.Error
	}
	return note, nil
}

func (d *Database) Delete(id string) error {
	trx := d.db.Where("id = ?", id).Delete(&Note{})
	if trx.Error != nil {
		d.logger.Error("could not delete note", slog.Any("error", trx.Error))
		return trx.Error
	}
	return nil
}