// Package recording handles persistence (SQLite), capture (Recorder), and
// playback (Player) of UDP telemetry frames.
package recording

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

	"git.destefano.cloud/texasmade/RocketLeagueBot-Renderer/internal/hub"
)

// Info is the JSON shape returned by /api/recordings.
type Info struct {
	ID         int64  `json:"id"`
	Name       string `json:"name"`
	CreatedAt  string `json:"created_at"`
	Frames     int    `json:"frames"`
	DurationMs int64  `json:"duration_ms"`
}

// OpenDB opens (or creates) the SQLite database and ensures the schema is
// up-to-date, performing any necessary additive migrations.
func OpenDB(path string) (*sql.DB, error) {
	db, err := sql.Open("sqlite3", path+"?_pragma=journal_mode(WAL)&_pragma=synchronous(NORMAL)&_pragma=foreign_keys(ON)")
	if err != nil {
		return nil, fmt.Errorf("open: %w", err)
	}
	db.SetMaxOpenConns(4)

	if _, err := db.Exec(`
		CREATE TABLE IF NOT EXISTS recordings (
			id INTEGER PRIMARY KEY AUTOINCREMENT,
			name TEXT NOT NULL,
			created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
			frames INTEGER DEFAULT 0,
			duration_ms INTEGER DEFAULT 0
		);
		CREATE TABLE IF NOT EXISTS frames (
			id INTEGER PRIMARY KEY AUTOINCREMENT,
			recording_id INTEGER NOT NULL,
			offset_ms INTEGER NOT NULL,
			data BLOB NOT NULL,
			FOREIGN KEY (recording_id) REFERENCES recordings(id) ON DELETE CASCADE
		);
		CREATE INDEX IF NOT EXISTS idx_frames_recording ON frames(recording_id, offset_ms);
		CREATE INDEX IF NOT EXISTS idx_recordings_created_at ON recordings(created_at);
	`); err != nil {
		return nil, fmt.Errorf("create tables: %w", err)
	}

	if !columnExists(db, "frames", "codec") {
		if _, err := db.Exec(`ALTER TABLE frames ADD COLUMN codec INTEGER NOT NULL DEFAULT 0`); err != nil {
			return nil, fmt.Errorf("add codec column: %w", err)
		}
		slog.Info("migration: added frames.codec column")
	}

	return db, nil
}

func columnExists(db *sql.DB, table, col string) bool {
	rows, err := db.Query(fmt.Sprintf("PRAGMA table_info(%s)", table))
	if err != nil {
		return false
	}
	defer rows.Close()
	for rows.Next() {
		var cid int
		var name, ctype string
		var notnull, pk int
		var dflt sql.NullString
		if err := rows.Scan(&cid, &name, &ctype, &notnull, &dflt, &pk); err != nil {
			continue
		}
		if name == col {
			return true
		}
	}
	return false
}

// List returns recordings ordered newest-first.
// since: optional RFC3339 timestamp lower bound (empty disables).
// limit: max rows (0 = no limit).
func List(db *sql.DB, since string, limit int) ([]Info, error) {
	q := `SELECT id, name, created_at, frames, duration_ms FROM recordings`
	args := []any{}
	if since != "" {
		if t, err := time.Parse(time.RFC3339, since); err == nil {
			q += ` WHERE created_at >= ?`
			args = append(args, t.UTC().Format("2006-01-02 15:04:05"))
		}
	}
	q += ` ORDER BY created_at DESC`
	if limit > 0 {
		q += ` LIMIT ?`
		args = append(args, limit)
	}
	rows, err := db.Query(q, args...)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	out := []Info{}
	for rows.Next() {
		var r Info
		if err := rows.Scan(&r.ID, &r.Name, &r.CreatedAt, &r.Frames, &r.DurationMs); err != nil {
			continue
		}
		out = append(out, r)
	}
	return out, nil
}

// Delete removes a recording by ID. CASCADE drops associated frames.
// Returns the rows affected.
func Delete(db *sql.DB, id int64) (int64, error) {
	res, err := db.Exec(`DELETE FROM recordings WHERE id = ?`, id)
	if err != nil {
		return 0, err
	}
	n, _ := res.RowsAffected()
	return n, nil
}

// CleanOld removes recordings older than retention and emits deletion events
// to the hub.
func CleanOld(db *sql.DB, h *hub.Hub, retention time.Duration) {
	cutoff := time.Now().Add(-retention).UTC().Format("2006-01-02 15:04:05")
	rows, err := db.Query(`SELECT id FROM recordings WHERE created_at < ?`, cutoff)
	if err != nil {
		slog.Error("cleanup query error", "err", err)
		return
	}
	var ids []int64
	for rows.Next() {
		var id int64
		if err := rows.Scan(&id); err == nil {
			ids = append(ids, id)
		}
	}
	rows.Close()
	if len(ids) == 0 {
		return
	}
	if _, err := db.Exec(`DELETE FROM recordings WHERE created_at < ?`, cutoff); err != nil {
		slog.Error("cleanup error", "err", err)
		return
	}
	slog.Info("cleaned old recordings", "n", len(ids))
	for _, id := range ids {
		h.PublishEvent(map[string]any{
			"type": "event", "kind": "recording_deleted",
			"recording": map[string]any{"id": id},
		})
	}
}

// DBSize returns the size of the database file in bytes, or 0 if it cannot
// be stat'd.
func DBSize(path string) int64 {
	if fi, err := os.Stat(path); err == nil {
		return fi.Size()
	}
	return 0
}