package findATender

import (
	"encoding/json"
	"slices"
	"strings"

	"git.avsdev.uk/Go/job-search/internal/findATender/ocds"
	"git.avsdev.uk/Go/job-search/internal/types"
)

func ocdsGetBuyerId(release *ocds.Release) string {
	if release.Buyer != nil {
		return string(release.Buyer.ID)
	}
	return ""
}
func ocdsGetBuyerName(release *ocds.Release) string {
	if release.Buyer != nil {
		return release.Buyer.Name
	}
	return ""
}

func ocdsConvertClassification(
	classif *ocds.Classification,
) types.ClassificationCode {
	return types.ClassificationCode{
		IsCPV:          strings.Compare(classif.Scheme, "CPV") == 0,
		Code:           string(classif.ID),
		Classification: classif.Description,
	}
}

func ocdsGetClassifications(release *ocds.Release) []types.ClassificationCode {
	classifications := make([]types.ClassificationCode, 0)
	if release.Tender == nil {
		return classifications
	}
	add := func(classif *ocds.Classification) {
		newClassif := ocdsConvertClassification(classif)
		found := slices.ContainsFunc(
			classifications, func(r types.ClassificationCode) bool {
				return r.Code == newClassif.Code
			},
		)
		if !found {
			classifications = append(classifications, newClassif)
		}
	}
	if release.Tender.Classification != nil {
		add(release.Tender.Classification)
	}
	for _, val := range release.Tender.Items {
		if val.Classification != nil {
			add(val.Classification)
		}
		for _, classif := range val.AdditionalClassifications {
			add(&classif)
		}
	}
	return classifications
}

func ocdsIsSMESuitable(release *ocds.Release) bool {
	if release.Tender == nil {
		return false
	}
	if len(release.Tender.Lots) == 0 {
		return false
	}
	for _, lot := range release.Tender.Lots {
		if lot.Suitability != nil {
			if lot.Suitability.SME != nil && *lot.Suitability.SME {
				return true
			}
		}
	}
	return false
}
func ocdsIsVCSESuitable(release *ocds.Release) bool {
	if release.Tender == nil {
		return false
	}
	if len(release.Tender.Lots) == 0 {
		return false
	}
	for _, lot := range release.Tender.Lots {
		if lot.Suitability != nil {
			if lot.Suitability.Vcse != nil && *lot.Suitability.Vcse {
				return true
			}
		}
	}
	return false
}

func ocdsRelease(release *ocds.Release) types.OpportunityRelease {
	tags := make([]types.OpportunityReleaseTag, 0)
	for _, val := range release.Tag {
		tags = append(tags, types.OpportunityReleaseTag{
			UUID:      release.OCID,
			ReleaseID: release.ID,
			Tag:       val,
		})
	}

	rel := types.OpportunityRelease{
		UUID:        release.OCID,
		ReleaseID:   release.ID,
		Tags:        tags,
		ReleaseDate: release.Date,
	}

	reencoded, err := json.Marshal(release)
	if err == nil {
		rel.JSON = string(reencoded)
	}

	return rel
}

func convertOne(release *ocds.Release) *types.Opportunity {
	t := &types.Opportunity{
		UUID:      release.OCID,
		UUIDType:  "ocid",
		BuyerId:   ocdsGetBuyerId(release),
		BuyerName: ocdsGetBuyerName(release),
	}

	if release.Tender != nil {
		t.Title = release.Tender.Title
		t.Status = release.Tender.Status
		t.Description = release.Tender.Description
		t.Classifications = ocdsGetClassifications(release)
		t.MainCategory = release.Tender.MainProcurementCategory
		t.ProcurementMethod = release.Tender.ProcurementMethod
		t.SMESuitable = ocdsIsSMESuitable(release)
		t.VCSESuitable = ocdsIsVCSESuitable(release)
		if release.Tender.TenderPeriod != nil {
			t.StartDate = release.Tender.TenderPeriod.StartDate
			t.EndDate = release.Tender.TenderPeriod.EndDate
		}
		if release.Tender.Value != nil && release.Tender.Value.Amount != nil {
			t.GrossValue = *release.Tender.Value.Amount
		}
		t.HasDocuments = len(release.Tender.Documents) > 0
		t.MultiLot = len(release.Tender.Lots) > 1
	}

	t.LatestReleaseDate = release.Date
	t.Releases = append(t.Releases, ocdsRelease(release))

	return t
}

// Convert groups releases by ocid into opportunities, in the order each ocid
// first appears. Each opportunity is built from its latest release (by date,
// or the later one in releases on a tie) and lists all of its releases oldest
// first.
func Convert(releases []ocds.Release) []*types.Opportunity {
	var order []string
	byOCID := make(map[string][]*ocds.Release)

	for idx := range releases {
		release := &releases[idx]
		if _, found := byOCID[release.OCID]; !found {
			order = append(order, release.OCID)
		}
		byOCID[release.OCID] = append(byOCID[release.OCID], release)
	}

	opportunities := make([]*types.Opportunity, 0, len(order))
	for _, ocid := range order {
		group := byOCID[ocid]

		slices.SortStableFunc(group, func(a, b *ocds.Release) int {
			return a.Date.Compare(b.Date)
		})

		opportunity := convertOne(group[len(group)-1])
		opportunity.Releases = make([]types.OpportunityRelease, 0, len(group))
		for _, release := range group {
			opportunity.Releases = append(opportunity.Releases, ocdsRelease(release))
		}
		opportunities = append(opportunities, opportunity)
	}

	return opportunities
}