package db

import (
	"context"
	"database/sql"
	"fmt"

	_ "modernc.org/sqlite"
)

func Open(path string) (*sql.DB, error) {
	db, err := sql.Open("sqlite", path+"?_journal=WAL&_timeout=5000&_fk=true")
	if err != nil {
		return nil, err
	}
	db.SetMaxOpenConns(1) // SQLite is single-writer
	if err := migrate(db); err != nil {
		db.Close()
		return nil, fmt.Errorf("migrate: %w", err)
	}
	return db, nil
}

func migrate(db *sql.DB) error {
	ctx := context.Background()
	if _, err := db.ExecContext(ctx, `CREATE TABLE IF NOT EXISTS schema_version (version INTEGER NOT NULL)`); err != nil {
		return err
	}
	var version int
	db.QueryRowContext(ctx, `SELECT COALESCE(MAX(version),0) FROM schema_version`).Scan(&version) //nolint

	migrations := []string{
		// v1: core schema
		`CREATE TABLE IF NOT EXISTS tickets (
			id INTEGER PRIMARY KEY AUTOINCREMENT,
			ticket_number INTEGER NOT NULL,
			user_id TEXT NOT NULL,
			panel TEXT NOT NULL,
			type TEXT NOT NULL,
			channel_id TEXT NOT NULL UNIQUE,
			opened_at DATETIME NOT NULL,
			claimed_by TEXT,
			claimed_at DATETIME,
			closed_at DATETIME,
			closed_by TEXT,
			reason TEXT,
			transcript_path TEXT,
			status TEXT NOT NULL DEFAULT 'open'
		);
		CREATE INDEX IF NOT EXISTS idx_tickets_user ON tickets(user_id);
		CREATE INDEX IF NOT EXISTS idx_tickets_status ON tickets(status);
		CREATE INDEX IF NOT EXISTS idx_tickets_type ON tickets(type);
		CREATE TABLE IF NOT EXISTS claim_messages (
			ticket_id INTEGER PRIMARY KEY,
			message_id TEXT NOT NULL,
			last_reup_at DATETIME NOT NULL
		);
		CREATE TABLE IF NOT EXISTS convocation_counter (
			id INTEGER PRIMARY KEY CHECK(id=1),
			count INTEGER NOT NULL DEFAULT 0
		);
		INSERT OR IGNORE INTO convocation_counter(id,count) VALUES(1,0);`,
	}

	for i, m := range migrations {
		v := i + 1
		if v <= version {
			continue
		}
		if _, err := db.ExecContext(ctx, m); err != nil {
			return fmt.Errorf("migration v%d: %w", v, err)
		}
		if _, err := db.ExecContext(ctx, `INSERT INTO schema_version(version) VALUES(?)`, v); err != nil {
			return fmt.Errorf("record migration v%d: %w", v, err)
		}
	}
	return nil
}