<?php

declare(strict_types=1);

function getDatabase(): PDO
{
    static $pdo = null;

    if ($pdo instanceof PDO) {
        return $pdo;
    }

    $databaseDirectory = dirname(__DIR__) . '/data';
    $databaseFile = $databaseDirectory . '/kanban.sqlite';

    if (!is_dir($databaseDirectory)) {
        if (!mkdir($databaseDirectory, 0775, true)) {
            throw new RuntimeException(
                'Unable to create the database directory.'
            );
        }
    }

    $pdo = new PDO('sqlite:' . $databaseFile);

    $pdo->setAttribute(
        PDO::ATTR_ERRMODE,
        PDO::ERRMODE_EXCEPTION
    );

    $pdo->setAttribute(
        PDO::ATTR_DEFAULT_FETCH_MODE,
        PDO::FETCH_ASSOC
    );

    $pdo->exec('PRAGMA foreign_keys = ON');
    $pdo->exec('PRAGMA busy_timeout = 5000');
    $pdo->exec('PRAGMA journal_mode = WAL');

    createSchema($pdo);

    return $pdo;
}

function createSchema(PDO $pdo): void
{
    $pdo->exec(
        <<<'SQL'
        CREATE TABLE IF NOT EXISTS kanban_tasks (
            id INTEGER PRIMARY KEY AUTOINCREMENT,

            column_id INTEGER NOT NULL
                CHECK (column_id BETWEEN 1 AND 6),

            position INTEGER NOT NULL DEFAULT 0,

            assign_to TEXT NOT NULL DEFAULT 'me',
            content TEXT NOT NULL,
            description TEXT,
            tags TEXT,
            color TEXT NOT NULL DEFAULT 'yellow',

            due_at TEXT,
            start_date TEXT,

            priority INTEGER NOT NULL DEFAULT 0
                CHECK (priority BETWEEN 0 AND 10),

            complexity INTEGER NOT NULL DEFAULT 0
                CHECK (complexity BETWEEN 0 AND 10),

            estimate_hours REAL,
            time_spent_hours REAL,

            created_at TEXT NOT NULL
                DEFAULT CURRENT_TIMESTAMP,

            updated_at TEXT NOT NULL
                DEFAULT CURRENT_TIMESTAMP
        );

        CREATE INDEX IF NOT EXISTS
            idx_kanban_tasks_column_position
        ON kanban_tasks (column_id, position);
        SQL
    );
}