package main

import (
	"database/sql"
	"log"
	"strings"
)

func runMigrations(database *sql.DB) {
	migrations := []string{
		`ALTER TABLE events ADD COLUMN description TEXT DEFAULT ''`,
		`ALTER TABLE events ADD COLUMN user_id INTEGER REFERENCES users(id)`,
		// Verification codes use a generic identifier column.
		`ALTER TABLE verification_codes ADD COLUMN identifier TEXT NOT NULL DEFAULT ''`,
		// Indexes for auth tables (created here so they run after column migrations).
		`CREATE INDEX IF NOT EXISTS idx_sessions_user ON sessions(user_id)`,
		`CREATE INDEX IF NOT EXISTS idx_verification_codes_identifier ON verification_codes(identifier)`,
		// Dedupe RSVPs: keep earliest per (event_id, name).
		`DELETE FROM rsvps WHERE id NOT IN (SELECT MIN(id) FROM rsvps GROUP BY event_id, name COLLATE NOCASE)`,
		// Plus-one tracking for RSVPs.
		`ALTER TABLE rsvps ADD COLUMN plus_one INTEGER NOT NULL DEFAULT 0`,
		// Drop legacy phone/email columns from verification_codes. They were
		// NOT NULL with no default, so inserts using only identifier failed.
		`DROP INDEX IF EXISTS idx_verification_codes_phone`,
		`DROP INDEX IF EXISTS idx_verification_codes_email`,
		`ALTER TABLE verification_codes DROP COLUMN phone`,
		`ALTER TABLE verification_codes DROP COLUMN email`,
		// SMS consent logging for Twilio compliance.
		`CREATE TABLE IF NOT EXISTS sms_consents (
			id         INTEGER PRIMARY KEY AUTOINCREMENT,
			phone      TEXT    NOT NULL,
			ip_address TEXT    NOT NULL DEFAULT '',
			user_agent TEXT    NOT NULL DEFAULT '',
			created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
		)`,
		// Attendee cap (0 = uncapped); capped events require login to RSVP.
		`ALTER TABLE events ADD COLUMN attendee_cap INTEGER NOT NULL DEFAULT 0`,
		`ALTER TABLE rsvps ADD COLUMN user_id INTEGER REFERENCES users(id)`,
	}
	for _, m := range migrations {
		_, err := database.Exec(m)
		if err != nil {
			if strings.Contains(err.Error(), "duplicate column name") ||
				strings.Contains(err.Error(), "no such column") {
				continue
			}
			log.Printf("migration warning: %v", err)
		}
	}

	rebuildLegacyUsersTable(database)
}

// rebuildLegacyUsersTable migrates users tables from the phone-auth era
// (phone NOT NULL, no email column). SQLite can't add a UNIQUE column or
// drop NOT NULL via ALTER TABLE, so the table has to be rebuilt. Detected
// by the missing email column.
func rebuildLegacyUsersTable(database *sql.DB) {
	var hasEmail int
	err := database.QueryRow(
		`SELECT COUNT(*) FROM pragma_table_info('users') WHERE name = 'email'`,
	).Scan(&hasEmail)
	if err != nil || hasEmail > 0 {
		return
	}

	// Disable FK enforcement so DROP TABLE users doesn't cascade-delete
	// sessions. main.go sets MaxOpenConns(1), so these pragmas apply to
	// the same connection the transaction runs on.
	database.Exec(`PRAGMA foreign_keys=OFF`)
	defer database.Exec(`PRAGMA foreign_keys=ON`)

	tx, err := database.Begin()
	if err != nil {
		log.Printf("users rebuild: %v", err)
		return
	}
	defer tx.Rollback()

	stmts := []string{
		`CREATE TABLE users_new (
			id         INTEGER PRIMARY KEY AUTOINCREMENT,
			phone      TEXT    UNIQUE,
			email      TEXT    UNIQUE,
			name       TEXT    NOT NULL DEFAULT '',
			created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
		)`,
		`INSERT INTO users_new (id, phone, name, created_at)
			SELECT id, phone, name, created_at FROM users`,
		`DROP TABLE users`,
		`ALTER TABLE users_new RENAME TO users`,
	}
	for _, stmt := range stmts {
		if _, err := tx.Exec(stmt); err != nil {
			log.Printf("users rebuild: %v", err)
			return
		}
	}
	if err := tx.Commit(); err != nil {
		log.Printf("users rebuild: %v", err)
	}
}