package database

import (
	"database/sql"
	"errors"
	"time"

	"git.noroutes.net/NoRoutes/vibetunes/internal/idgen"
)

// Permissions mirrors the Subsonic REST API's per-user role model.
// AdminRole is represented separately by User.IsAdmin (an admin
// implicitly has every permission below regardless of these flags).
type Permissions struct {
	Settings        bool
	Stream          bool
	Download        bool
	Upload          bool
	Playlist        bool
	CoverArt        bool
	Comment         bool
	Podcast         bool
	Share           bool
	Jukebox         bool
	VideoConversion bool
}

type User struct {
	ID                 string
	Username           string
	Email              string
	PasswordHash       sql.NullString
	IsAdmin            bool
	Disabled           bool
	ExternalAuth       bool
	Permissions        Permissions
	SubsonicAuthSecret sql.NullString // AES-GCM encrypted password, for Subsonic token auth; see internal/subsonic
	CreatedAt          time.Time
	LastLoginAt        sql.NullTime
}

// Allows reports whether the user may perform the action gated by
// permission p — admins can do everything regardless of individual
// flags.
func (u *User) Allows(p bool) bool {
	return u.IsAdmin || p
}

var ErrNotFound = errors.New("not found")

func CountUsers(db *sql.DB) (int, error) {
	var n int
	err := db.QueryRow(`SELECT COUNT(*) FROM users`).Scan(&n)
	return n, err
}

const userColumns = `id, username, email, password_hash, is_admin, disabled, external_auth,
	role_settings, role_stream, role_download, role_upload, role_playlist, role_cover_art,
	role_comment, role_podcast, role_share, role_jukebox, role_video_conversion,
	subsonic_auth_secret, created_at, last_login_at`

// CreateUser inserts a new user. passwordHash may be empty for
// external-auth-only accounts. New non-admin users get the default
// permission set (stream/download/playlist/coverArt/comment/share).
func CreateUser(db *sql.DB, username, email, passwordHash string, isAdmin bool) (*User, error) {
	id := idgen.New("us")
	var hash sql.NullString
	if passwordHash != "" {
		hash = sql.NullString{String: passwordHash, Valid: true}
	}
	_, err := db.Exec(`INSERT INTO users (id, username, email, password_hash, is_admin) VALUES (?, ?, ?, ?, ?)`,
		id, username, email, nullStringVal(hash), boolInt(isAdmin))
	if err != nil {
		return nil, err
	}
	return GetUserByID(db, id)
}

// CreateExternalUser inserts a user with no local password, created on
// first login via a trusted reverse-proxy identity header.
func CreateExternalUser(db *sql.DB, username string) (*User, error) {
	id := idgen.New("us")
	_, err := db.Exec(`INSERT INTO users (id, username, external_auth) VALUES (?, ?, 1)`, id, username)
	if err != nil {
		return nil, err
	}
	return GetUserByID(db, id)
}

func GetUserByID(db *sql.DB, id string) (*User, error) {
	return scanUser(db.QueryRow(`SELECT `+userColumns+` FROM users WHERE id = ?`, id))
}

func GetUserByUsername(db *sql.DB, username string) (*User, error) {
	return scanUser(db.QueryRow(`SELECT `+userColumns+` FROM users WHERE username = ?`, username))
}

func scanUser(row *sql.Row) (*User, error) {
	var u User
	var isAdmin, disabled, external int
	var pSettings, pStream, pDownload, pUpload, pPlaylist, pCoverArt, pComment, pPodcast, pShare, pJukebox, pVideoConv int
	var createdAt string
	var lastLogin sql.NullString
	err := row.Scan(&u.ID, &u.Username, &u.Email, &u.PasswordHash, &isAdmin, &disabled, &external,
		&pSettings, &pStream, &pDownload, &pUpload, &pPlaylist, &pCoverArt, &pComment, &pPodcast, &pShare, &pJukebox, &pVideoConv,
		&u.SubsonicAuthSecret, &createdAt, &lastLogin)
	if errors.Is(err, sql.ErrNoRows) {
		return nil, ErrNotFound
	}
	if err != nil {
		return nil, err
	}
	u.IsAdmin = isAdmin != 0
	u.Disabled = disabled != 0
	u.ExternalAuth = external != 0
	u.Permissions = Permissions{
		Settings: pSettings != 0, Stream: pStream != 0, Download: pDownload != 0, Upload: pUpload != 0,
		Playlist: pPlaylist != 0, CoverArt: pCoverArt != 0, Comment: pComment != 0, Podcast: pPodcast != 0,
		Share: pShare != 0, Jukebox: pJukebox != 0, VideoConversion: pVideoConv != 0,
	}
	u.CreatedAt, _ = parseTime(createdAt)
	if lastLogin.Valid {
		if t, err := parseTime(lastLogin.String); err == nil {
			u.LastLoginAt = sql.NullTime{Time: t, Valid: true}
		}
	}
	return &u, nil
}

func ListUsers(db *sql.DB) ([]*User, error) {
	rows, err := db.Query(`SELECT ` + userColumns + ` FROM users ORDER BY username COLLATE NOCASE`)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var out []*User
	for rows.Next() {
		u, err := scanUserRow(rows)
		if err != nil {
			return nil, err
		}
		out = append(out, u)
	}
	return out, rows.Err()
}

func scanUserRow(rows *sql.Rows) (*User, error) {
	var u User
	var isAdmin, disabled, external int
	var pSettings, pStream, pDownload, pUpload, pPlaylist, pCoverArt, pComment, pPodcast, pShare, pJukebox, pVideoConv int
	var createdAt string
	var lastLogin sql.NullString
	err := rows.Scan(&u.ID, &u.Username, &u.Email, &u.PasswordHash, &isAdmin, &disabled, &external,
		&pSettings, &pStream, &pDownload, &pUpload, &pPlaylist, &pCoverArt, &pComment, &pPodcast, &pShare, &pJukebox, &pVideoConv,
		&u.SubsonicAuthSecret, &createdAt, &lastLogin)
	if err != nil {
		return nil, err
	}
	u.IsAdmin = isAdmin != 0
	u.Disabled = disabled != 0
	u.ExternalAuth = external != 0
	u.Permissions = Permissions{
		Settings: pSettings != 0, Stream: pStream != 0, Download: pDownload != 0, Upload: pUpload != 0,
		Playlist: pPlaylist != 0, CoverArt: pCoverArt != 0, Comment: pComment != 0, Podcast: pPodcast != 0,
		Share: pShare != 0, Jukebox: pJukebox != 0, VideoConversion: pVideoConv != 0,
	}
	u.CreatedAt, _ = parseTime(createdAt)
	if lastLogin.Valid {
		if t, err := parseTime(lastLogin.String); err == nil {
			u.LastLoginAt = sql.NullTime{Time: t, Valid: true}
		}
	}
	return &u, nil
}

func SetUserPassword(db *sql.DB, userID, passwordHash string) error {
	_, err := db.Exec(`UPDATE users SET password_hash = ? WHERE id = ?`, passwordHash, userID)
	return err
}

// SetUserSubsonicAuthSecret stores (or clears, with encrypted="") the
// AES-GCM encrypted copy of the user's current plaintext password, used
// only to verify legacy Subsonic token authentication.
func SetUserSubsonicAuthSecret(db *sql.DB, userID, encrypted string) error {
	var v any
	if encrypted != "" {
		v = encrypted
	}
	_, err := db.Exec(`UPDATE users SET subsonic_auth_secret = ? WHERE id = ?`, v, userID)
	return err
}

func SetUserDisabled(db *sql.DB, userID string, disabled bool) error {
	_, err := db.Exec(`UPDATE users SET disabled = ? WHERE id = ?`, boolInt(disabled), userID)
	return err
}

func SetUserAdmin(db *sql.DB, userID string, isAdmin bool) error {
	_, err := db.Exec(`UPDATE users SET is_admin = ? WHERE id = ?`, boolInt(isAdmin), userID)
	return err
}

// SetUserPermissions updates the full Subsonic permission set for a user.
func SetUserPermissions(db *sql.DB, userID string, p Permissions) error {
	_, err := db.Exec(`UPDATE users SET
		role_settings=?, role_stream=?, role_download=?, role_upload=?, role_playlist=?,
		role_cover_art=?, role_comment=?, role_podcast=?, role_share=?, role_jukebox=?, role_video_conversion=?
		WHERE id=?`,
		boolInt(p.Settings), boolInt(p.Stream), boolInt(p.Download), boolInt(p.Upload), boolInt(p.Playlist),
		boolInt(p.CoverArt), boolInt(p.Comment), boolInt(p.Podcast), boolInt(p.Share), boolInt(p.Jukebox), boolInt(p.VideoConversion),
		userID)
	return err
}

func DeleteUser(db *sql.DB, userID string) error {
	_, err := db.Exec(`DELETE FROM users WHERE id = ?`, userID)
	return err
}

func TouchLastLogin(db *sql.DB, userID string) error {
	_, err := db.Exec(`UPDATE users SET last_login_at = strftime('%Y-%m-%dT%H:%M:%fZ','now') WHERE id = ?`, userID)
	return err
}

// --- Per-user music folder restrictions ---

// AllowedMusicFolderIDs returns the music folder IDs a user is
// restricted to, or nil if the user has no restriction (sees every
// folder — the default and common case).
func AllowedMusicFolderIDs(db *sql.DB, userID string) ([]string, error) {
	rows, err := db.Query(`SELECT music_folder_id FROM user_music_folders WHERE user_id = ?`, userID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var out []string
	for rows.Next() {
		var id string
		if err := rows.Scan(&id); err != nil {
			return nil, err
		}
		out = append(out, id)
	}
	return out, rows.Err()
}

// SetAllowedMusicFolders replaces a user's folder restriction list. An
// empty ids slice removes all restrictions (unrestricted access).
func SetAllowedMusicFolders(db *sql.DB, userID string, ids []string) error {
	tx, err := db.Begin()
	if err != nil {
		return err
	}
	defer tx.Rollback()
	if _, err := tx.Exec(`DELETE FROM user_music_folders WHERE user_id = ?`, userID); err != nil {
		return err
	}
	for _, id := range ids {
		if _, err := tx.Exec(`INSERT INTO user_music_folders (user_id, music_folder_id) VALUES (?, ?)`, userID, id); err != nil {
			return err
		}
	}
	return tx.Commit()
}

func boolInt(b bool) int {
	if b {
		return 1
	}
	return 0
}

func nullStringVal(s sql.NullString) any {
	if !s.Valid {
		return nil
	}
	return s.String
}

func parseTime(s string) (time.Time, error) {
	return time.Parse("2006-01-02T15:04:05.999999999Z", s)
}

// SetUserEmail updates a user's email address.
func SetUserEmail(db *sql.DB, userID, email string) error {
	_, err := db.Exec(`UPDATE users SET email = ? WHERE id = ?`, email, userID)
	return err
}