package spells

import (
	"sort"

	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd"
)

func canonicalizeResponse(response *extractionResponse) {
	if response == nil {
		return
	}
	for index := range response.SpellCasts {
		canonicalizeSpellCast(&response.SpellCasts[index])
	}
	sort.SliceStable(response.SpellCasts, func(i, j int) bool {
		left, leftOK := earliestSourceUnit(response.SpellCasts[i])
		right, rightOK := earliestSourceUnit(response.SpellCasts[j])
		if leftOK != rightOK {
			return leftOK
		}
		if !leftOK {
			return false
		}
		return left < right
	})
}

func canonicalizeSpellCast(spell *spellCastResponse) {
	sort.SliceStable(spell.SourceRefs, func(i, j int) bool {
		left := spell.SourceRefs[i]
		right := spell.SourceRefs[j]
		if left.StartUnitID != right.StartUnitID {
			return unitSortValue(left.StartUnitID) < unitSortValue(right.StartUnitID)
		}
		return unitSortValue(left.EndUnitID) < unitSortValue(right.EndUnitID)
	})
	spell.SourceRefs = dedupeSourceRefs(spell.SourceRefs)
}

func dedupeSourceRefs(refs []spellSourceRefResponse) []spellSourceRefResponse {
	if len(refs) < 2 {
		return refs
	}
	out := refs[:0]
	var previous spellSourceRefResponse
	for index, ref := range refs {
		if index > 0 && sameSourceRef(previous, ref) {
			continue
		}
		out = append(out, ref)
		previous = ref
	}
	return out
}

func sameSourceRef(left spellSourceRefResponse, right spellSourceRefResponse) bool {
	return left.StartUnitID == right.StartUnitID && left.EndUnitID == right.EndUnitID
}

func earliestSourceUnit(spell spellCastResponse) (int, bool) {
	for _, ref := range spell.SourceRefs {
		start := ref.StartUnitID
		if start > 0 {
			return start, true
		}
	}
	return 0, false
}

func unitSortValue(value int) int {
	if value <= 0 {
		return int(^uint(0) >> 1)
	}
	return value
}

func canonicalSpellList(response extractionResponse, sourceID string) dnd.SpellList {
	spellCasts := make([]dnd.SpellCast, len(response.SpellCasts))
	for index, spell := range response.SpellCasts {
		refs := make([]source.SourceRef, len(spell.SourceRefs))
		for refIndex, ref := range spell.SourceRefs {
			refs[refIndex] = source.SourceRef{
				SourceID:    sourceID,
				StartUnitID: ref.StartUnitID,
				EndUnitID:   ref.EndUnitID,
			}
		}
		spellCasts[index] = dnd.SpellCast{
			Caster:     spell.Caster,
			Spell:      spell.Spell,
			SourceRefs: refs,
		}
	}
	if response.SpellCasts == nil {
		spellCasts = nil
	}
	return dnd.SpellList{SpellCasts: spellCasts}
}