package judge

import (
	"encoding/json"
	"strconv"
	"strings"
)

// FitAnswer is a with its shown bodies cut until its JSON is within limit bytes (MaxAnswerBytes for the node's key):
// first the bodies' texts, from the last differing module back, keeping their paths; then the paths too. What is cut
// is said in the answer's note. The verdict and every list of modules are never cut.
func FitAnswer(a CandidateAnswer, limit int) CandidateAnswer {
	size := func() int {
		raw, err := json.Marshal(a)
		if err != nil {
			return 0
		}
		return len(raw)
	}
	if size() <= limit {
		return a
	}
	a.Differs = append([]ModuleDiffers(nil), a.Differs...)
	for i := range a.Differs {
		a.Differs[i].Bodies = append([]ResourceBodies(nil), a.Differs[i].Bodies...)
	}
	cutTexts, cutPaths := false, false
	for i := len(a.Differs) - 1; i >= 0 && size() > limit; i-- {
		for j := range a.Differs[i].Bodies {
			a.Differs[i].Bodies[j].Composed, a.Differs[i].Bodies[j].Running = "", ""
		}
		cutTexts = true
	}
	for i := len(a.Differs) - 1; i >= 0 && size() > limit; i-- {
		for j := range a.Differs[i].Bodies {
			a.Differs[i].Bodies[j].Paths = nil
		}
		cutPaths = true
	}
	why := "the bodies shown were cut to keep the answer within " + strconv.Itoa(limit>>10) + " KiB"
	if cutPaths {
		why += ", their paths too"
	}
	if cutTexts {
		a.Note = strings.TrimPrefix(a.Note+"; ", "; ") + why
	}
	return a
}