csv to multimarkdown

csvToMMD.swift

#!/usr/bin/swift -suppress-warnings
// based on https://chrisbrandow.svbtle.com/csv-to-multimarkdown-tables
import Foundation

let separators: [Character: String] = ["=": ":---:", ">": "----:", "<": ":----"]
let separatorSet = CharacterSet(charactersIn: "><=, ")

func csv(data: String) -> [[String]] {
    var result: [[String]] = []
    let rows = data.components(separatedBy: "\n")
    for row in rows {
        if row.count > 0{
            let columns = row.trimmingCharacters(in: .whitespacesAndNewlines).components(separatedBy: ",")
            result.append(columns)
        }
        
    }
    return result
}


func titleAndEntriesFrom(string: String) -> (String, String?, [String])? {
    var lines = string.components(separatedBy: "\n")
    guard lines.count > 1, let titleLine = lines.first else {
        print("need more than one line ->")
        return nil
    }

    lines.removeFirst()
    let separatorMarkdown: String?
    if let second = lines.first, CharacterSet(charactersIn: second).isSubset(of: separatorSet) {
        separatorMarkdown = separatorFrom(line: second)
        lines.removeFirst()
    } else {
        separatorMarkdown = nil
    }
    return (titleLine, separatorMarkdown, lines)
}

func max_by_row(data: [[String]]) -> [Int] {
     let columns = data[0].count
     // min length is 5 ie :---:
     var the_max = Array(repeating: 5, count: columns)
     for row in data {
        guard row.count == columns else{
            continue; // TODO what if empty cells?
        }
         for col in 0..<columns {
             the_max[col] = max(the_max[col], row[col].count)
         }
     }
    return the_max
}

func max_by_row(val1: [Int], val2: [Int]) -> [Int] {
    var res = val1
    for i in 0..<val1.count {
        res[i] = max(val1[i], val2[i])
    }
    return res
}

func mdTableFrom(components: (String, String?, [String])) -> String? {
    let titles = csv(data:components.0)
    let body = csv(data:components.2.joined(separator: "\n"))
    let maxLength = max_by_row(val1: max_by_row(data: titles), val2: max_by_row(data: body))

    var titleMarkdown = ""
    var bodyMarkdown = ""
    var separatorMarkdown = ""
    for i in 0..<maxLength.count {
       titleMarkdown += " | " + (titles[0][i] as NSString).padding(toLength:maxLength[i], withPad: " ", startingAt: 0)
    }
    titleMarkdown += " |\n"

    for i in 0..<maxLength.count {
       separatorMarkdown += " | :" + "".padding(toLength:maxLength[i]-2, withPad: "-", startingAt: 0) + ":"
    }
    separatorMarkdown += " |\n"

    for j in 0..<body.count {
        for i in 0..<maxLength.count {
            if i < body[j].count{
                bodyMarkdown += " | " + (body[j][i] as NSString).padding(toLength:maxLength[i], withPad: " ", startingAt: 0)    
            }
        }
        bodyMarkdown += " |\n"
    }

    //let titleMarkdown = markdownFrom(line: components.0)
    //let titleEntries = components.0.components(separatedBy: ",")
    //let separatorMarkdown = components.1 ?? titleEntries.reduce("\n| "){prev, sep in "\(prev) :---: | "}
    //let bodyMarkdown = components.2.reduce(""){prev, line in "\(prev) \(markdownFrom(line: line))"}

    return titleMarkdown + separatorMarkdown + bodyMarkdown
}

func separatorFrom(line: String) -> String {
    let entries = line.components(separatedBy: ",")
    let things = entries.flatMap({$0.trimmingCharacters(in: CharacterSet.whitespaces).characters.first})
    let markdown = things.reduce("\n|"){prev, entry in "\(prev) \(separators[entry] ?? ":xxx:") |"}
    return markdown
}

func markdownFrom(line: String) -> String {
    guard line.characters.count > 0 else {
        return "\n"
    }
    let entries = line.components(separatedBy: ",")
    return entries.reduce("\n| "){prev, entry in "\(prev) \(entry.trimmingCharacters(in: CharacterSet.whitespaces)) |"}
}

var string = ""

while let thing = readLine(strippingNewline: false) {
    string += thing
}

if let titleAndBody = titleAndEntriesFrom(string: string), let output = mdTableFrom(components: titleAndBody) {
    print(output)
} else {
    print(string)
}