// retoor <retoor@molodetz.nl>

import "scheduler" for Scheduler, Future

class DataProcessor {
    static parse { async { |text| text.split(",") } }
    static filter { async { |list, fn|
        var result = []
        for (item in list) {
            if (fn.call(item)) result.add(item)
        }
        return result
    }}
    static transform { async { |list, fn|
        var result = []
        for (item in list) {
            result.add(fn.call(item))
        }
        return result
    }}
    static join { async { |list, sep| list.join(sep) } }

    static pipeline(data) {
        var parse = DataProcessor.parse
        var filter = DataProcessor.filter
        var transform = DataProcessor.transform
        var join = DataProcessor.join
        var parsed = await parse(data)
        var filtered = await filter(parsed) { |s| s.count > 4 }
        var transformed = await transform(filtered) { |s| s.toList[0] }
        return await join(transformed, "-")
    }
}

var data = "apple,banana,cherry,date"

var parse = DataProcessor.parse
var parsed = await parse(data)
System.print(parsed) // expect: [apple, banana, cherry, date]

var filter = DataProcessor.filter
var filtered = await filter(parsed) { |s| s.count > 5 }
System.print(filtered) // expect: [banana, cherry]

var transform = DataProcessor.transform
var transformed = await transform(filtered) { |s| s.toList[0] }
System.print(transformed) // expect: [b, c]

var join = DataProcessor.join
var joined = await join(transformed, "-")
System.print(joined) // expect: b-c

var result = DataProcessor.pipeline("one,two,three,four,five")
System.print(result) // expect: t