package httpapi

import (
	"context"
	"fmt"

	"github.com/dtoro/oikos/internal/db/sqlcgen"
	"github.com/dtoro/oikos/internal/domain"
	"github.com/dtoro/oikos/internal/httpapi/gen"
	"github.com/dtoro/oikos/internal/observability"
	"github.com/jackc/pgx/v5"
)

// ─── Patterns ──────────────────────────────────────────────────────────

func (s *Server) ListPatterns(ctx context.Context, req gen.ListPatternsRequestObject) (gen.ListPatternsResponseObject, error) {
	limit := clampLimit(req.Params.Limit)
	rows, err := s.pool.Query(ctx, `
		SELECT p.entity_id, e.slug, p.applies_type, p.action, p.pattern, p.confidence,
		       p.evidence_count, p.success_count, p.failure_count, p.status,
		       p.quarantined, p.version, p.last_validated_at
		FROM patterns p
		JOIN entities e ON e.id = p.entity_id
		WHERE ($1::text IS NULL OR p.status = $1)
		  AND ($2::text IS NULL OR p.applies_type = $2)
		  AND ($3::text IS NULL OR p.action = $3)
		ORDER BY p.applies_type, p.action
		LIMIT $4`,
		req.Params.Status, req.Params.EntityType, req.Params.Action, limit+1)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	items := []gen.Pattern{}
	for rows.Next() {
		var p gen.Pattern
		if err := rows.Scan(&p.Id, &p.Slug, &p.AppliesType, &p.Action, &p.Pattern,
			&p.Confidence, &p.EvidenceCount, &p.SuccessCount, &p.FailureCount,
			&p.Status, &p.Quarantined, &p.Version, &p.LastValidatedAt); err != nil {
			return nil, err
		}
		items = append(items, p)
	}
	if rows.Err() != nil {
		return nil, rows.Err()
	}

	if items == nil {
		items = []gen.Pattern{}
	}
	return gen.ListPatterns200JSONResponse{Items: items}, nil
}

func (s *Server) PatchPattern(ctx context.Context, req gen.PatchPatternRequestObject) (gen.PatchPatternResponseObject, error) {
	if req.Body == nil {
		return nil, fmt.Errorf("%w: request body is required", domain.ErrInvalidInput)
	}

	id, err := s.resolveEntityID(ctx, req.Id)
	if err != nil {
		return nil, err
	}

	tx, err := s.pool.Begin(ctx)
	if err != nil {
		return nil, err
	}
	defer tx.Rollback(ctx)
	q := sqlcgen.New(tx)

	if req.Body.Status != nil {
		status := string(*req.Body.Status)
		if err := q.UpdatePatternStatus(ctx, sqlcgen.UpdatePatternStatusParams{
			EntityID: id,
			Status:   status,
		}); err != nil {
			if err == pgx.ErrNoRows {
				return nil, fmt.Errorf("%w: pattern %s", domain.ErrNotFound, req.Id)
			}
			return nil, err
		}
	}

	if req.Body.Quarantined != nil {
		if err := q.UpdatePatternQuarantine(ctx, sqlcgen.UpdatePatternQuarantineParams{
			EntityID:    id,
			Quarantined: *req.Body.Quarantined,
		}); err != nil {
			return nil, err
		}
	}

	// Re-read.
	var p gen.Pattern
	err = tx.QueryRow(ctx, `
		SELECT entity_id, applies_type, action, pattern, confidence,
		       evidence_count, success_count, failure_count, status,
		       quarantined, version, last_validated_at
		FROM patterns WHERE entity_id = $1`, id).
		Scan(&p.Id, &p.AppliesType, &p.Action, &p.Pattern,
			&p.Confidence, &p.EvidenceCount, &p.SuccessCount, &p.FailureCount,
			&p.Status, &p.Quarantined, &p.Version, &p.LastValidatedAt)
	if err != nil {
		if err == pgx.ErrNoRows {
			return nil, fmt.Errorf("%w: pattern %s", domain.ErrNotFound, req.Id)
		}
		return nil, err
	}

	actorType, actor := actorInfo(ctx)
	if auditErr := observability.Audit(ctx, q, actorType, actor, "patch",
		&id, "PATCH", "/api/v1/patterns/"+req.Id, "",
		map[string]any{"status": req.Body.Status, "quarantined": req.Body.Quarantined}); auditErr != nil {
		return nil, auditErr
	}

	if err := tx.Commit(ctx); err != nil {
		return nil, err
	}

	return gen.PatchPattern200JSONResponse(p), nil
}