//
//  TableFormatter.swift
//  Metrika
//
//  Author:  Simon-Pierre Boucher
//  Contact: contact@spboucher.ai
//  Copyright © 2026 Simon-Pierre Boucher. All rights reserved.
//

import Foundation

/// Console table rendering: monospaced, right-aligned numeric columns in
/// the Stata output tradition.
enum TableFormatter {

    /// Stata-flavored general format: up to `significant` significant
    /// digits, no trailing zeros, leading "0." collapsed to ".".
    static func general(_ value: Double, significant: Int = 7) -> String {
        if value.isNaN { return "." }
        if value == 0 { return "0" }
        var text = String(format: "%.\(significant)g", value)
        if text.contains("."), !text.contains("e"), !text.contains("E") {
            while text.hasSuffix("0") { text.removeLast() }
            if text.hasSuffix(".") { text.removeLast() }
        }
        if text.hasPrefix("0.") { text.removeFirst() }
        if text.hasPrefix("-0.") { text = "-" + text.dropFirst(2) }
        return text
    }

    static func fixed(_ value: Double, decimals: Int) -> String {
        value.isNaN ? "." : String(format: "%.\(decimals)f", value)
    }

    static func pad(_ text: String, _ width: Int, right: Bool = true) -> String {
        if text.count >= width { return text }
        let padding = String(repeating: " ", count: width - text.count)
        return right ? padding + text : text + padding
    }

    /// Renders rows of cells with per-column widths; the first column is
    /// left-padded to its width and separated by " | ".
    static func rule(_ widths: [Int]) -> String {
        let first = String(repeating: "-", count: widths[0] + 1)
        let rest = widths.dropFirst().reduce(0) { $0 + $1 } + (widths.count - 1) * 2
        return first + "+" + String(repeating: "-", count: rest + 1)
    }
}