// Package adminstore is the read/write data-access layer for the admin console.
// Unlike the public store (read-only), it performs INSERT/UPDATE/DELETE and
// records field-level provenance (source = "manual") plus an audit_log entry
// for every write, then recomputes product.quality_score.
package adminstore

import (
	"context"
	"encoding/json"
	"errors"
	"strconv"
	"time"

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

// ErrNotFound is returned when a requested row does not exist.
var ErrNotFound = errors.New("not found")

// Store wraps a pgx pool for admin operations.
type Store struct {
	pool *pgxpool.Pool
}

// New constructs an admin Store.
func New(pool *pgxpool.Pool) *Store { return &Store{pool: pool} }

// Ping verifies DB connectivity.
func (s *Store) Ping(ctx context.Context) error { return s.pool.Ping(ctx) }

// CompletenessFields mirrors ingestion/opengoods/etl/quality.py COMPLETENESS_FIELDS.
var CompletenessFields = []string{
	"name", "gtin", "brand", "category", "net_content",
	"country_of_origin", "nutriments", "ingredients", "image",
}

// ---------- list ----------

// ProductRow is a list-view row for the admin product table.
type ProductRow struct {
	ID           string   `json:"id"`
	GTIN         *string  `json:"gtin"`
	Name         string   `json:"name"`
	Brand        *string  `json:"brand"`
	CategoryPath *string  `json:"category_path"`
	Status       string   `json:"status"`
	QualityScore float64  `json:"quality_score"`
	Missing      []string `json:"missing"`
	UpdatedAt    string   `json:"updated_at"`
}

// ListProducts returns a paginated, optionally name/gtin-filtered list.
func (s *Store) ListProducts(ctx context.Context, q string, limit, offset int) ([]ProductRow, int, error) {
	args := []any{}
	where := "WHERE 1=1"
	if q != "" {
		args = append(args, q)
		where += " AND (p.name ILIKE '%' || $1 || '%' OR p.gtin ILIKE '%' || $1 || '%')"
	}

	var total int
	if err := s.pool.QueryRow(ctx, "SELECT count(*) FROM product p "+where, args...).Scan(&total); err != nil {
		return nil, 0, err
	}

	args = append(args, limit, offset)
	sql := `
SELECT p.id, p.gtin, p.name, b.name, c.path::text, p.status, p.quality_score,
       p.updated_at,
       (p.brand_id IS NOT NULL) AS has_brand,
       (p.category_id IS NOT NULL) AS has_cat,
       (p.net_content_canonical IS NOT NULL) AS has_net,
       (p.country_of_origin IS NOT NULL AND p.country_of_origin <> '') AS has_country,
       (f.nutriments IS NOT NULL AND f.nutriments::text <> '{}') AS has_nutri,
       (f.ingredients_text IS NOT NULL AND f.ingredients_text <> '') AS has_ing,
       EXISTS (SELECT 1 FROM product_image pi WHERE pi.product_id = p.id) AS has_img
FROM product p
LEFT JOIN brand b ON b.id = p.brand_id
LEFT JOIN category c ON c.id = p.category_id
LEFT JOIN food_detail f ON f.product_id = p.id ` + where +
		" ORDER BY p.updated_at DESC LIMIT $" + strconv.Itoa(len(args)-1) + " OFFSET $" + strconv.Itoa(len(args))

	rows, err := s.pool.Query(ctx, sql, args...)
	if err != nil {
		return nil, 0, err
	}
	defer rows.Close()

	out := []ProductRow{}
	for rows.Next() {
		var r ProductRow
		var hasBrand, hasCat, hasNet, hasCountry, hasNutri, hasIng, hasImg bool
		var updated time.Time
		if err := rows.Scan(&r.ID, &r.GTIN, &r.Name, &r.Brand, &r.CategoryPath, &r.Status,
			&r.QualityScore, &updated, &hasBrand, &hasCat, &hasNet, &hasCountry,
			&hasNutri, &hasIng, &hasImg); err != nil {
			return nil, 0, err
		}
		r.UpdatedAt = updated.Format(time.RFC3339)
		present := map[string]bool{
			"name":              r.Name != "",
			"gtin":              r.GTIN != nil && *r.GTIN != "",
			"brand":             hasBrand,
			"category":          hasCat,
			"net_content":       hasNet,
			"country_of_origin": hasCountry,
			"nutriments":        hasNutri,
			"ingredients":       hasIng,
			"image":             hasImg,
		}
		r.Missing = []string{}
		for _, f := range CompletenessFields {
			if !present[f] {
				r.Missing = append(r.Missing, f)
			}
		}
		out = append(out, r)
	}
	return out, total, rows.Err()
}

// ---------- detail ----------

// ProductImage is one image row.
type ProductImage struct {
	ID      string  `json:"id"`
	URL     string  `json:"url"`
	Kind    string  `json:"kind"`
	License *string `json:"license"`
}

// MSRP is one suggested-retail-price snapshot.
type MSRP struct {
	ID            string  `json:"id"`
	Amount        float64 `json:"amount"`
	Currency      string  `json:"currency"`
	Region        string  `json:"region"`
	EffectiveDate *string `json:"effective_date"`
	SourceURL     *string `json:"source_url"`
	Note          *string `json:"note"`
}

// ProductDetail is the full editable view of a product.
type ProductDetail struct {
	ID              string         `json:"id"`
	GTIN            *string        `json:"gtin"`
	Name            string         `json:"name"`
	BrandID         *string        `json:"brand_id"`
	Brand           *string        `json:"brand"`
	CategoryID      *string        `json:"category_id"`
	CategoryPath    *string        `json:"category_path"`
	NetContentValue *float64       `json:"net_content_value"`
	NetContentUnit  *string        `json:"net_content_unit"`
	CountryOfOrigin *string        `json:"country_of_origin"`
	Status          string         `json:"status"`
	QualityScore    float64        `json:"quality_score"`
	IngredientsText *string        `json:"ingredients_text"`
	Allergens       []string       `json:"allergens"`
	Additives       []string       `json:"additives"`
	Nutriments      map[string]any `json:"nutriments"`
	NutritionBasis  *string        `json:"nutrition_basis"`
	ServingSize     *string        `json:"serving_size"`
	NutriScore      *string        `json:"nutri_score"`
	Barcodes        []Barcode      `json:"barcodes"`
	Images          []ProductImage `json:"images"`
	MSRP            []MSRP         `json:"msrp"`
	Missing         []string       `json:"missing"`
	UpdatedAt       string         `json:"updated_at"`
}

// GetProduct returns the full editable detail for one product.
func (s *Store) GetProduct(ctx context.Context, id string) (*ProductDetail, error) {
	var d ProductDetail
	var nutriments []byte
	var updated time.Time
	err := s.pool.QueryRow(ctx, `
SELECT p.id, p.gtin, p.name, p.brand_id, b.name, p.category_id, c.path::text,
       p.net_content_value, p.net_content_unit, p.country_of_origin, p.status,
       p.quality_score, p.updated_at,
       f.ingredients_text, f.allergens, f.additives, f.nutriments,
       f.nutrition_basis, f.serving_size, f.nutri_score
FROM product p
LEFT JOIN brand b ON b.id = p.brand_id
LEFT JOIN category c ON c.id = p.category_id
LEFT JOIN food_detail f ON f.product_id = p.id
WHERE p.id = $1`, id).Scan(
		&d.ID, &d.GTIN, &d.Name, &d.BrandID, &d.Brand, &d.CategoryID, &d.CategoryPath,
		&d.NetContentValue, &d.NetContentUnit, &d.CountryOfOrigin, &d.Status,
		&d.QualityScore, &updated,
		&d.IngredientsText, &d.Allergens, &d.Additives, &nutriments,
		&d.NutritionBasis, &d.ServingSize, &d.NutriScore,
	)
	if errors.Is(err, pgx.ErrNoRows) {
		return nil, ErrNotFound
	}
	if err != nil {
		return nil, err
	}
	d.UpdatedAt = updated.Format(time.RFC3339)
	if len(nutriments) > 0 {
		_ = json.Unmarshal(nutriments, &d.Nutriments)
	}
	if d.Allergens == nil {
		d.Allergens = []string{}
	}
	if d.Additives == nil {
		d.Additives = []string{}
	}

	bcs, err := s.listBarcodes(ctx, id)
	if err != nil {
		return nil, err
	}
	d.Barcodes = bcs

	imgs, err := s.listImages(ctx, id)
	if err != nil {
		return nil, err
	}
	d.Images = imgs

	msrps, err := s.listMSRP(ctx, id)
	if err != nil {
		return nil, err
	}
	d.MSRP = msrps

	d.Missing = missingFromDetail(&d)
	return &d, nil
}

func missingFromDetail(d *ProductDetail) []string {
	present := map[string]bool{
		"name":              d.Name != "",
		"gtin":              d.GTIN != nil && *d.GTIN != "",
		"brand":             d.BrandID != nil,
		"category":          d.CategoryID != nil,
		"net_content":       d.NetContentValue != nil,
		"country_of_origin": d.CountryOfOrigin != nil && *d.CountryOfOrigin != "",
		"nutriments":        len(d.Nutriments) > 0,
		"ingredients":       d.IngredientsText != nil && *d.IngredientsText != "",
		"image":             len(d.Images) > 0,
	}
	missing := []string{}
	for _, f := range CompletenessFields {
		if !present[f] {
			missing = append(missing, f)
		}
	}
	return missing
}

func (s *Store) listImages(ctx context.Context, productID string) ([]ProductImage, error) {
	rows, err := s.pool.Query(ctx,
		"SELECT id, url, kind, license FROM product_image WHERE product_id = $1 ORDER BY id", productID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	out := []ProductImage{}
	for rows.Next() {
		var im ProductImage
		if err := rows.Scan(&im.ID, &im.URL, &im.Kind, &im.License); err != nil {
			return nil, err
		}
		out = append(out, im)
	}
	return out, rows.Err()
}

func (s *Store) listMSRP(ctx context.Context, productID string) ([]MSRP, error) {
	rows, err := s.pool.Query(ctx, `
SELECT id, amount, currency, region, effective_date::text, source_url, note
FROM product_msrp WHERE product_id = $1 ORDER BY effective_date DESC NULLS LAST`, productID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	out := []MSRP{}
	for rows.Next() {
		var m MSRP
		if err := rows.Scan(&m.ID, &m.Amount, &m.Currency, &m.Region, &m.EffectiveDate, &m.SourceURL, &m.Note); err != nil {
			return nil, err
		}
		out = append(out, m)
	}
	return out, rows.Err()
}