package discovery

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"

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

var (
	ErrProfileNotFound     = errors.New("profile not found")
	ErrNoSignatures        = errors.New("no signatures available for enrichment")
	ErrAlreadyEnriched     = errors.New("profile already enriched")
	ErrLLMNotConfigured    = errors.New("llm provider not configured")
	ErrProfileNotSuggested = errors.New("profile is not available for enrichment")
)

type ProfileEnrichResponse struct {
	ProfileID        string           `json:"profile_id"`
	EnrichmentStatus EnrichmentStatus `json:"enrichment_status"`
}

func (s *Service) StartProfileEnrichment(ctx context.Context, externalUserID, profileID string) (ProfileEnrichResponse, error) {
	sigs, err := s.loadProfileSignatures(ctx, profileID)
	if err != nil {
		return ProfileEnrichResponse{}, err
	}
	if len(sigs) == 0 {
		return ProfileEnrichResponse{}, ErrNoSignatures
	}

	llmSettings, _ := s.loadLLMSettings(ctx, externalUserID)
	if !llmSettingsHasProvider(llmSettings) {
		return ProfileEnrichResponse{}, ErrLLMNotConfigured
	}

	tag, err := s.db.Exec(ctx, `
		UPDATE contact_discovered_profiles p
		SET enrichment_status = 'enriching', updated_at = NOW()
		FROM users u
		WHERE p.user_id = u.id
		  AND u.external_id = $1
		  AND p.id = $2::uuid
		  AND p.status = 'suggested'
		  AND p.enrichment_status NOT IN ('enriched', 'enriching')
	`, externalUserID, profileID)
	if err != nil {
		return ProfileEnrichResponse{}, err
	}
	if tag.RowsAffected() == 0 {
		var status ProfileStatus
		var enrichStatus EnrichmentStatus
		err := s.db.QueryRow(ctx, `
			SELECT p.status, p.enrichment_status
			FROM contact_discovered_profiles p
			JOIN users u ON p.user_id = u.id
			WHERE u.external_id = $1 AND p.id = $2::uuid
		`, externalUserID, profileID).Scan(&status, &enrichStatus)
		if err != nil {
			if err == pgx.ErrNoRows {
				return ProfileEnrichResponse{}, ErrProfileNotFound
			}
			return ProfileEnrichResponse{}, err
		}
		if status != ProfileSuggested {
			return ProfileEnrichResponse{}, ErrProfileNotSuggested
		}
		if enrichStatus == EnrichEnriched {
			return ProfileEnrichResponse{}, ErrAlreadyEnriched
		}
		if enrichStatus == EnrichEnriching {
			return ProfileEnrichResponse{
				ProfileID:        profileID,
				EnrichmentStatus: EnrichEnriching,
			}, nil
		}
		return ProfileEnrichResponse{}, fmt.Errorf("profile not enrichable")
	}

	ncUserID, bookID := s.resolveDiscoveryNCContext(ctx, externalUserID)
	go s.runProfileEnrichment(externalUserID, profileID, ncUserID, bookID)

	return ProfileEnrichResponse{
		ProfileID:        profileID,
		EnrichmentStatus: EnrichEnriching,
	}, nil
}

func (s *Service) runProfileEnrichment(externalUserID, profileID, ncUserID, bookID string) {
	ctx := context.Background()
	defer func() {
		if r := recover(); r != nil {
			s.logger.Error("profile enrichment panicked", "profile_id", profileID, "panic", r)
			_, _ = s.db.Exec(ctx, `
				UPDATE contact_discovered_profiles
				SET enrichment_status = 'failed', updated_at = NOW()
				WHERE id = $1::uuid AND enrichment_status = 'enriching'
			`, profileID)
		}
	}()

	profile, err := s.getProfileByID(ctx, externalUserID, profileID)
	if err != nil {
		s.logger.Warn("profile enrichment load profile failed", "profile_id", profileID, "error", err)
		s.markProfileEnrichmentFailed(ctx, profileID)
		return
	}

	sigs, err := s.loadProfileSignatures(ctx, profileID)
	if err != nil || len(sigs) == 0 {
		s.markProfileEnrichmentFailed(ctx, profileID)
		return
	}

	llmSettings, err := s.loadLLMSettings(ctx, externalUserID)
	if err != nil || !llmSettingsHasProvider(llmSettings) {
		s.markProfileEnrichmentFailed(ctx, profileID)
		return
	}

	enriched, enrichErr := enrichWithLLMTimeout(
		ctx, s.llm, llmSettings,
		profile.PrimaryEmail, profile.DisplayName, sigs, llmEnrichTimeout,
	)
	if enrichErr != nil {
		s.logger.Warn("profile enrichment llm failed", "profile_id", profileID, "error", enrichErr)
		s.markProfileEnrichmentFailed(ctx, profileID)
		return
	}

	rejections, _ := s.loadRejections(ctx, externalUserID)
	if err := s.applyEnrichmentResults(ctx, externalUserID, profileID, profile.PrimaryEmail, enriched, ncUserID, bookID, rejections); err != nil {
		s.logger.Warn("profile enrichment persist failed", "profile_id", profileID, "error", err)
		s.markProfileEnrichmentFailed(ctx, profileID)
		return
	}

	s.inferMissingCompanies(ctx, externalUserID, ncUserID, bookID)
}

func (s *Service) markProfileEnrichmentFailed(ctx context.Context, profileID string) {
	_, _ = s.db.Exec(ctx, `
		UPDATE contact_discovered_profiles
		SET enrichment_status = 'failed', updated_at = NOW()
		WHERE id = $1::uuid AND enrichment_status = 'enriching'
	`, profileID)
}

func (s *Service) applyEnrichmentResults(
	ctx context.Context,
	externalUserID, profileID, email string,
	enriched *EnrichedContactData,
	ncUserID, bookID string,
	rejections map[string]bool,
) error {
	enrichedJSON, _ := json.Marshal(enriched)
	_, err := s.db.Exec(ctx, `
		UPDATE contact_discovered_profiles
		SET enrichment_status = 'enriched', enriched_data = $2::jsonb, enriched_at = NOW(), updated_at = NOW()
		WHERE id = $1::uuid
	`, profileID, string(enrichedJSON))
	if err != nil {
		return err
	}

	var existingContacts []ncContact
	if ncUserID != "" {
		existingContacts = s.loadNCContacts(ctx, ncUserID, bookID)
	}
	match := findExistingContact(existingContacts, email)

	var suggestions []Suggestion
	if match != nil {
		suggestions = enrichExistingContactSuggestions(profileID, match.UID, enriched, match)
	} else {
		suggestions = enrichedDataToSuggestions(externalUserID, profileID, enriched)
	}

	for _, sug := range suggestions {
		if match != nil && suggestionAlreadyOnContact(match, sug) {
			continue
		}
		rejKey := fmt.Sprintf("field:%s:%s:%s", profileID, sug.FieldPath, sug.SuggestedValue)
		if rejections[rejKey] {
			continue
		}
		_, _ = s.db.Exec(ctx, `
			INSERT INTO contact_enrichment_suggestions (
				user_id, profile_id, suggestion_type, field_path, suggested_value, suggested_label, confidence, status
			)
			VALUES (
				(SELECT id FROM users WHERE external_id = $1), $2::uuid, $3, $4, $5, $6, $7, 'pending'
			)
			ON CONFLICT (user_id, profile_id, field_path, suggested_value) DO UPDATE SET
				status = CASE
					WHEN contact_enrichment_suggestions.status = 'rejected' THEN 'rejected'
					ELSE 'pending'
				END,
				confidence = EXCLUDED.confidence
		`, externalUserID, profileID, sug.SuggestionType, sug.FieldPath, sug.SuggestedValue, sug.SuggestedLabel, sug.Confidence)
	}
	return nil
}