package configkit_test

import (
	"testing"

	configkit "go.maximumdirect.net/configkit"
)

func TestTierHistoryRecordsEachContributionOnce(t *testing.T) {
	t.Parallel()
	for _, middle := range []string{"mid", "low"} {
		t.Run(middle, func(t *testing.T) {
			result, err := configkit.LoadLayered[map[string]any](
				configkit.Input{Source: configkit.Bytes("main", []byte("x: high\n"))},
				configkit.LayeredOptions[map[string]any]{Underlays: []configkit.Underlay{
					{Inputs: []configkit.Input{{Source: configkit.Bytes("low", []byte("x: low\n"))}}},
					{Inputs: []configkit.Input{{Source: configkit.Bytes("middle", []byte("x: "+middle+"\n"))}}},
				}},
			)
			if err != nil {
				t.Fatal(err)
			}
			history := result.Metadata().History(configkit.Keys("x"))
			if len(history) != 3 {
				t.Fatalf("history has %d records; want the three independent contributions", len(history))
			}
			explanation, found := result.Explain(configkit.Keys("x"))
			if !found || len(explanation.History) != len(history) {
				t.Fatal("explanation lost ordered tier contributions")
			}
			for index, sourceID := range []string{"source-2", "source-3", "source-1"} {
				change := history[index]
				if len(change.Origin.Locations) != 1 || change.Origin.Locations[0].SourceID != sourceID {
					t.Fatalf("contribution %d has origin %#v", index, change.Origin)
				}
				if len(explanation.History[index].Origin.Locations) != 1 || explanation.History[index].Origin.Locations[0] != change.Origin.Locations[0] {
					t.Fatalf("explanation contribution %d has a different source origin", index)
				}
				if index == 0 {
					if len(change.Previous) != 0 {
						t.Fatal("first source contribution has a previous origin")
					}
				} else if len(change.Previous) != 1 || len(change.Previous[0].Locations) != 1 ||
					change.Previous[0].Locations[0] != history[index-1].Origin.Locations[0] {
					t.Fatalf("contribution %d has incorrect previous origin %#v", index, change.Previous)
				}
			}
		})
	}
}