package httpapi

import (
	"context"
	"errors"
	"net/http"
	"strings"

	"github.com/descrybe/descrybe-v2/apps/api/internal/platformsettings"
	"github.com/google/uuid"
	"github.com/jackc/pgx/v5/pgxpool"
)

var errStoreReconnectPoolUnavailable = errors.New("database unavailable")

// StoreReconnectGap is one connected-but-invalid store connector for a tenant.
// "Invalid" matches merchant needsStoreReconnect: store identity exists but secrets are missing.
type StoreReconnectGap struct {
	CompanyID      uuid.UUID `json:"company_id"`
	CompanyName    string    `json:"company_name"`
	Channel        string    `json:"channel"`
	Identity       string    `json:"identity"`
	IsEnabled      bool      `json:"is_enabled"`
	Reason         string    `json:"reason"`
	LastTestStatus string    `json:"last_test_status,omitempty"`
}

// StoreReconnectInventory is the admin list payload for credential-gap stores.
type StoreReconnectInventory struct {
	Stores []StoreReconnectGap `json:"stores"`
	Total  int                 `json:"total"`
	Limit  int                 `json:"limit"`
	Offset int                 `json:"offset"`
}

const storeReconnectReasonMissingCredentials = "missing_credentials"

// ListStoreReconnectGaps returns companies with Woo/Shopify identity but no usable credential blobs.
// Presence-only (no decrypt) — same honesty bar as has_credentials=false in GetConfig for empty secrets.
func ListStoreReconnectGaps(ctx context.Context, pool *pgxpool.Pool, limit, offset int) (StoreReconnectInventory, error) {
	out := StoreReconnectInventory{
		Stores: []StoreReconnectGap{},
		Limit:  limit,
		Offset: offset,
	}
	if pool == nil {
		return out, errStoreReconnectPoolUnavailable
	}
	if limit <= 0 {
		limit = 50
	}
	if limit > 200 {
		limit = 200
	}
	if offset < 0 {
		offset = 0
	}
	out.Limit = limit
	out.Offset = offset

	const q = `
WITH gaps AS (
	SELECT c.id AS company_id, c.name AS company_name,
		'shopify'::text AS channel,
		NULLIF(BTRIM(sc.shop_domain), '') AS identity,
		sc.is_enabled,
		COALESCE(sc.last_test_status, '') AS last_test_status
	FROM companies c
	JOIN shopify_configs sc ON sc.company_id = c.id
	WHERE c.id <> $1
		AND NULLIF(BTRIM(sc.shop_domain), '') IS NOT NULL
		AND COALESCE(LENGTH(sc.access_token), 0) = 0
		AND COALESCE(NULLIF(BTRIM(sc.sync_options->>'client_id'), ''), '') = ''
		AND COALESCE(NULLIF(BTRIM(sc.sync_options->>'client_secret_enc'), ''), '') = ''
	UNION ALL
	SELECT c.id, c.name, 'woocommerce',
		NULLIF(BTRIM(wc.store_url), ''),
		wc.is_enabled,
		COALESCE(wc.last_test_status, '')
	FROM companies c
	JOIN woocommerce_configs wc ON wc.company_id = c.id
	WHERE c.id <> $1
		AND NULLIF(BTRIM(wc.store_url), '') IS NOT NULL
		AND (
			COALESCE(LENGTH(wc.consumer_key), 0) = 0
			OR COALESCE(LENGTH(wc.consumer_secret), 0) = 0
		)
)
SELECT COUNT(*) OVER() AS total,
	company_id, company_name, channel, identity, is_enabled, last_test_status
FROM gaps
ORDER BY company_name ASC, channel ASC
LIMIT $2 OFFSET $3`

	rows, err := pool.Query(ctx, q, platformsettings.SystemCompanyID, limit, offset)
	if err != nil {
		return out, err
	}
	defer rows.Close()

	for rows.Next() {
		var row StoreReconnectGap
		var total int
		if err := rows.Scan(
			&total,
			&row.CompanyID,
			&row.CompanyName,
			&row.Channel,
			&row.Identity,
			&row.IsEnabled,
			&row.LastTestStatus,
		); err != nil {
			return out, err
		}
		row.Reason = storeReconnectReasonMissingCredentials
		row.Identity = strings.TrimSpace(row.Identity)
		row.LastTestStatus = strings.TrimSpace(row.LastTestStatus)
		out.Total = total
		out.Stores = append(out.Stores, row)
	}
	if err := rows.Err(); err != nil {
		return out, err
	}
	return out, nil
}

func (s *Server) handleAdminListStoreReconnectGaps(w http.ResponseWriter, r *http.Request) {
	if s.Pool == nil {
		Error(w, http.StatusServiceUnavailable, "database unavailable")
		return
	}
	limit, offset := ParseLimitOffset(r)
	inv, err := ListStoreReconnectGaps(r.Context(), s.Pool, limit, offset)
	if err != nil {
		Error(w, http.StatusInternalServerError, "store reconnect inventory failed")
		return
	}
	JSON(w, http.StatusOK, inv)
}