import type Database from 'better-sqlite3';

/** Provisioning outcomes remain report inputs even after the policy is removed. */
export function installMetricsProvisioningRevisions(handle: Database.Database) {
    for (const table of ['server_deployments', 'provisioning_sources'])
        for (const action of ['INSERT', 'UPDATE', 'DELETE']) {
            const versions =
                action === 'INSERT' ? ['NEW'] : action === 'DELETE' ? ['OLD'] : ['OLD', 'NEW'];
            const fields = ['server', 'action', 'state', 'started_at', 'finished_at'];
            const condition =
                table === 'provisioning_sources'
                    ? versions.map((row) => `${row}.kind='autoscaling'`).join(' OR ')
                    : `EXISTS (SELECT 1 FROM provisioning_sources WHERE operation_id=${action === 'DELETE' ? 'OLD' : 'NEW'}.id AND kind='autoscaling')${
                          action === 'UPDATE'
                              ? ` AND (${fields.map((field) => `OLD.${field} IS NOT NEW.${field}`).join(' OR ')})`
                              : ''
                      }`;
            handle.exec(`CREATE TRIGGER IF NOT EXISTS report_metrics_${table}_${action}
                AFTER ${action} ON ${table} WHEN ${condition}
                BEGIN UPDATE report_revisions SET revision=revision+1 WHERE topic='metrics'; END;`);
        }
}

/** Match demand includes active and interrupted matches, independent of leaderboard eligibility. */
export function installMetricsMatchRevisions(handle: Database.Database) {
    for (const table of ['leaderboard_matches', 'leaderboard_match_players'])
        for (const action of ['INSERT', 'UPDATE', 'DELETE']) {
            const fields =
                table === 'leaderboard_matches' ? ['game', 'map_name', 'started_at'] : ['match_id'];
            // Score/presence heartbeats do not change distinct participant counts.
            const condition =
                action === 'UPDATE'
                    ? `WHEN ${fields.map((field) => `OLD.${field} IS NOT NEW.${field}`).join(' OR ')}`
                    : '';
            handle.exec(`CREATE TRIGGER IF NOT EXISTS report_metrics_${table}_${action}
                AFTER ${action} ON ${table} ${condition}
                BEGIN UPDATE report_revisions SET revision=revision+1 WHERE topic='metrics'; END;`);
        }
}

/** Current policy settings are inputs to historical metrics advice. */
export function installMetricsPolicyRevisions(handle: Database.Database) {
    for (const table of ['autoscaling_policies', 'settings'])
        for (const action of ['INSERT', 'UPDATE', 'DELETE']) {
            const versions =
                action === 'INSERT' ? ['NEW'] : action === 'DELETE' ? ['OLD'] : ['OLD', 'NEW'];
            const condition =
                table === 'settings'
                    ? `WHEN ${versions.map((row) => `${row}.key='autoscaling_paused'`).join(' OR ')}`
                    : '';
            handle.exec(`CREATE TRIGGER IF NOT EXISTS report_metrics_${table}_${action}
                AFTER ${action} ON ${table} ${condition}
                BEGIN UPDATE report_revisions SET revision=revision+1 WHERE topic='metrics'; END;`);
        }
}

export function installReportRevisions(handle: Database.Database) {
    handle.exec(`CREATE TABLE IF NOT EXISTS report_revisions (topic TEXT PRIMARY KEY, revision INTEGER NOT NULL DEFAULT 0);
        INSERT OR IGNORE INTO report_revisions(topic) VALUES ('metrics'), ('leaderboard');`);
    for (const table of ['metric_samples', 'servers'])
        for (const action of ['INSERT', 'UPDATE', 'DELETE']) {
            const condition =
                table === 'servers' && action === 'UPDATE'
                    ? 'WHEN OLD.destroyed_at IS NOT NEW.destroyed_at OR OLD.name IS NOT NEW.name'
                    : '';
            handle.exec(`CREATE TRIGGER IF NOT EXISTS report_${table}_${action} AFTER ${action} ON ${table} ${condition}
            BEGIN UPDATE report_revisions SET revision=revision+1 WHERE topic='metrics'; END;`);
        }
    if (handle.prepare("SELECT 1 FROM settings WHERE key='completed_report_revisions_v1'").get())
        return;
    handle.transaction(() => {
        for (const table of [
            'leaderboard_matches',
            'leaderboard_match_players',
            'leaderboard_players'
        ]) {
            for (const action of ['INSERT', 'UPDATE', 'DELETE']) {
                const name = `report_${table}_${action}`;
                const versions =
                    action === 'INSERT' ? ['NEW'] : action === 'DELETE' ? ['OLD'] : ['OLD', 'NEW'];
                const condition =
                    table === 'leaderboard_matches'
                        ? `WHEN ${versions.map((row) => `${row}.status='completed'`).join(' OR ')}`
                        : table === 'leaderboard_match_players'
                          ? `WHEN ${versions.map((row) => `(SELECT status FROM leaderboard_matches WHERE id=${row}.match_id)='completed'`).join(' OR ')}`
                          : action === 'UPDATE'
                            ? 'WHEN OLD.name IS NOT NEW.name'
                            : '';
                const event =
                    table === 'leaderboard_players' && action === 'UPDATE'
                        ? 'UPDATE OF name'
                        : action;
                handle.exec(`DROP TRIGGER IF EXISTS ${name};
                    CREATE TRIGGER ${name} AFTER ${event} ON ${table} ${condition}
                    BEGIN UPDATE report_revisions SET revision=revision+1 WHERE topic='leaderboard'; END;`);
            }
        }
        handle.exec("INSERT INTO settings(key,value) VALUES('completed_report_revisions_v1','1')");
    })();
}