package awards

import (
	"context"
	"errors"
	"time"

	"github.com/jackc/pgx/v5/pgtype"

	"github.com/missionworkforce/missionmatch/internal/platform/database/dbgen"
	"github.com/missionworkforce/missionmatch/internal/platform/tenant"
)

// ErrNoDatabase is returned when no pool is configured.
var ErrNoDatabase = errors.New("awards: no database configured")

const (
	defaultIncumbentLimit = 5
	maxLimit              = 50
)

// Service reads the cached awards catalog.
type Service struct{ db *tenant.DB }

// NewService builds the service. db may be nil (then calls return ErrNoDatabase).
func NewService(db *tenant.DB) *Service { return &Service{db: db} }

// Incumbents returns the largest comparable awards for the given NAICS codes, excluding Galapagos own
// awards. Returns an empty slice when no NAICS is supplied.
func (s *Service) Incumbents(ctx context.Context, naics []string, limit int) ([]Award, error) {
	if s.db == nil {
		return nil, ErrNoDatabase
	}
	if len(naics) == 0 {
		return []Award{}, nil
	}
	leaf, release, err := s.db.Acquire(ctx)
	if err != nil {
		return nil, err
	}
	defer release()
	if leaf.Pool == nil {
		return nil, ErrNoDatabase
	}
	rows, err := dbgen.New(leaf.Pool).ListAwardsByNaics(ctx, dbgen.ListAwardsByNaicsParams{
		Naics: naics,
		Lim:   int32(clampLimit(limit, defaultIncumbentLimit)),
	})
	if err != nil {
		return nil, err
	}
	return toViews(rows), nil
}

// Galapagos returns Galapagos own past performance, largest first.
func (s *Service) Galapagos(ctx context.Context, limit int) ([]Award, error) {
	if s.db == nil {
		return nil, ErrNoDatabase
	}
	leaf, release, err := s.db.Acquire(ctx)
	if err != nil {
		return nil, err
	}
	defer release()
	if leaf.Pool == nil {
		return nil, ErrNoDatabase
	}
	rows, err := dbgen.New(leaf.Pool).ListGalapagosAwards(ctx, int32(clampLimit(limit, 10)))
	if err != nil {
		return nil, err
	}
	return toViews(rows), nil
}

func clampLimit(v, def int) int {
	if v <= 0 {
		return def
	}
	if v > maxLimit {
		return maxLimit
	}
	return v
}

func toViews(rows []dbgen.UsaspendingAward) []Award {
	out := make([]Award, 0, len(rows))
	for _, r := range rows {
		out = append(out, toView(r))
	}
	return out
}

func toView(r dbgen.UsaspendingAward) Award {
	amount := ""
	if r.AwardAmount != nil {
		amount = r.AwardAmount.StringFixed(2)
	}
	return Award{
		AwardUID:          r.GeneratedInternalID,
		AwardID:           r.AwardID,
		RecipientName:     r.RecipientName,
		RecipientUEI:      r.RecipientUei,
		AwardAmount:       amount,
		AwardingAgency:    r.AwardingAgency,
		AwardingSubAgency: r.AwardingSubAgency,
		POPStartDate:      dateStr(r.PopStartDate),
		POPEndDate:        dateStr(r.PopEndDate),
		NaicsCode:         r.NaicsCode,
		NaicsDescription:  r.NaicsDescription,
		Description:       r.Description,
		IsGalapagos:       r.IsGalapagos,
		Source:            r.Source,
		SyncedAt:          r.SyncedAt.Format(time.RFC3339),
	}
}

func dateStr(d pgtype.Date) string {
	if !d.Valid {
		return ""
	}
	return d.Time.Format("2006-01-02")
}