// Two-Level Write (TLW) — writes to corporate.db AND Paddle in one call.
//
// NOTE: This is a minimal subset of admin/sync.go for the public web server's
// onboarding flow. Both files share the same corporate.db and Paddle API.
// When the public web server and admin server merge, this file goes away and
// admin/sync.go becomes the canonical implementation.

package main

import (
	"bytes"
	"database/sql"
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
	"strings"
	"time"
)

// corpDB is the connection to corporate.db (customers, addresses, subscriptions).
// It's separate from `db` (clavitor.db, which holds POPs/telemetry/etc).
var corpDB *sql.DB

// tlwSandbox is true when we should hit the Paddle sandbox API instead of live.
// Auto-detected from CLAVITOR_PADDLE_LIVE env var (default: sandbox).
var tlwSandbox = os.Getenv("CLAVITOR_PADDLE_LIVE") != "1"

// paddleAPIKey is loaded from PADDLE_API_KEY env var. Empty = TLW writes to DB
// only and skips Paddle (useful for local dev without sandbox credentials).
var paddleAPIKey = os.Getenv("PADDLE_API_KEY")

// initTLW opens corporate.db and configures the TLW.
// Refuses to create the file or the schema — both must already exist.
// If either is missing, returns an error and onboarding stays disabled.
// Called from main() after the regular db is opened.
func initTLW() error {
	// `mode=rw` makes sqlite refuse to create a missing file (otherwise
	// the driver would silently create an empty one — exactly the
	// foot-gun we want to avoid).
	if _, err := os.Stat("corporate.db"); err != nil {
		return fmt.Errorf("corporate.db not found (must be provisioned externally): %w", err)
	}

	var err error
	corpDB, err = sql.Open("sqlite3", "corporate.db?mode=rw&_busy_timeout=5000")
	if err != nil {
		return fmt.Errorf("open corporate.db: %w", err)
	}
	if err := corpDB.Ping(); err != nil {
		return fmt.Errorf("ping corporate.db: %w", err)
	}

	// Verify the schema is present. We do not create it.
	var hasCustomers int
	corpDB.QueryRow(`SELECT COUNT(*) FROM sqlite_master WHERE type='table' AND name='customers'`).Scan(&hasCustomers)
	if hasCustomers == 0 {
		corpDB.Close()
		corpDB = nil
		return fmt.Errorf("corporate.db is missing the customers table — schema must be applied externally")
	}

	if tlwSandbox {
		log.Println("TLW: Paddle SANDBOX mode")
	} else {
		log.Println("TLW: Paddle LIVE mode")
	}
	if paddleAPIKey == "" {
		log.Println("TLW: PADDLE_API_KEY not set — DB-only mode (Paddle calls skipped)")
	}
	return nil
}

// paddleBaseURL returns the API base URL based on sandbox mode.
func paddleBaseURL() string {
	if tlwSandbox {
		return "https://sandbox-api.paddle.com"
	}
	return "https://api.paddle.com"
}

// tlwResult is what every TLW Create call returns.
type tlwResult struct {
	OurID    string // Our internal ID (we generate this)
	PaddleID string // Paddle's returned ID (empty if Paddle skipped or failed)
	Synced   bool   // True if Paddle accepted the write
	Err      error  // DB error or last Paddle error
}

// tlwCreateCustomer writes a new customer to corporate.db and Paddle.
// Required fields in data: email. Optional: name, locale, marketing_consent.
func tlwCreateCustomer(data map[string]interface{}) tlwResult {
	if data["email"] == nil || data["email"] == "" {
		return tlwResult{Err: fmt.Errorf("email required")}
	}

	now := time.Now().Unix()
	ourID := fmt.Sprintf("ctm_%d", time.Now().UnixNano())
	row := map[string]interface{}{
		"id":            ourID,
		"email":         data["email"],
		"name":          data["name"],
		"locale":        firstNonEmpty(data["locale"], "en"),
		"status":        "active",
		"level":         1,
		"created_at":    now,
		"updated_at":    now,
		"sync_status":   "pending",
		"pending_since": now,
	}

	if err := tlwInsert("customers", row); err != nil {
		return tlwResult{OurID: ourID, Err: fmt.Errorf("db insert: %w", err)}
	}

	// Push to Paddle
	if paddleAPIKey == "" {
		return tlwResult{OurID: ourID, Synced: false}
	}
	payload := map[string]interface{}{
		"email":  data["email"],
		"locale": row["locale"],
	}
	if data["name"] != nil && data["name"] != "" {
		payload["name"] = data["name"]
	}
	resp, err := paddleCall("POST", "/customers", payload)
	if err != nil {
		corpDB.Exec(`UPDATE customers SET sync_status='error', sync_error=? WHERE id=?`, err.Error(), ourID)
		return tlwResult{OurID: ourID, Err: err}
	}
	paddleID := extractPaddleID(resp)
	corpDB.Exec(`UPDATE customers SET paddle_id=?, sync_status='synced', sync_error=NULL, last_paddle_sync_at=? WHERE id=?`,
		paddleID, time.Now().Unix(), ourID)
	return tlwResult{OurID: ourID, PaddleID: paddleID, Synced: true}
}

// tlwCreateAddress writes a billing address tied to a customer.
// Required: customer_id, country_code. Optional: city, region, zip_code, description.
func tlwCreateAddress(data map[string]interface{}) tlwResult {
	if data["customer_id"] == nil || data["customer_id"] == "" {
		return tlwResult{Err: fmt.Errorf("customer_id required")}
	}
	if data["country_code"] == nil || data["country_code"] == "" {
		return tlwResult{Err: fmt.Errorf("country_code required")}
	}

	now := time.Now().Unix()
	ourID := fmt.Sprintf("add_%d", time.Now().UnixNano())
	row := map[string]interface{}{
		"id":            ourID,
		"customer_id":   data["customer_id"],
		"description":   data["description"],
		"city":          data["city"],
		"region":        data["region"],
		"country_code":  data["country_code"],
		"zip_code":      data["zip_code"],
		"status":        "active",
		"created_at":    now,
		"updated_at":    now,
		"sync_status":   "pending",
		"pending_since": now,
	}
	if err := tlwInsert("addresses", row); err != nil {
		return tlwResult{OurID: ourID, Err: fmt.Errorf("db insert: %w", err)}
	}

	if paddleAPIKey == "" {
		return tlwResult{OurID: ourID, Synced: false}
	}

	// Need the Paddle customer ID to call /customers/{id}/addresses
	var paddleCustomerID string
	corpDB.QueryRow(`SELECT paddle_id FROM customers WHERE id = ?`, data["customer_id"]).Scan(&paddleCustomerID)
	if paddleCustomerID == "" {
		corpDB.Exec(`UPDATE addresses SET sync_status='error', sync_error=? WHERE id=?`,
			"customer not synced to paddle yet", ourID)
		return tlwResult{OurID: ourID, Err: fmt.Errorf("customer has no paddle_id yet")}
	}

	payload := map[string]interface{}{
		"country_code": data["country_code"],
	}
	for _, k := range []string{"city", "region", "zip_code", "description"} {
		if v, ok := data[k]; ok && v != "" {
			payload[k] = v
		}
	}
	resp, err := paddleCall("POST", "/customers/"+paddleCustomerID+"/addresses", payload)
	if err != nil {
		corpDB.Exec(`UPDATE addresses SET sync_status='error', sync_error=? WHERE id=?`, err.Error(), ourID)
		return tlwResult{OurID: ourID, Err: err}
	}
	paddleID := extractPaddleID(resp)
	corpDB.Exec(`UPDATE addresses SET paddle_id=?, sync_status='synced', sync_error=NULL, last_paddle_sync_at=? WHERE id=?`,
		paddleID, time.Now().Unix(), ourID)
	return tlwResult{OurID: ourID, PaddleID: paddleID, Synced: true}
}

// tlwCreateTransaction creates a Paddle transaction (used to generate a checkout URL).
// Returns the Paddle transaction ID and the hosted checkout URL.
// Unlike customer/address, transactions are not stored in corporate.db until the
// webhook fires — we just need the checkout URL to redirect the user.
func tlwCreateTransaction(paddleCustomerID, paddleAddressID, priceID string) (txnID, checkoutURL string, err error) {
	if paddleAPIKey == "" {
		// Dev/local mode: synthesize a placeholder
		return "txn_local_dev", "/onboarding/done?dev=1", nil
	}
	payload := map[string]interface{}{
		"customer_id": paddleCustomerID,
		"address_id":  paddleAddressID,
		"items": []map[string]interface{}{
			{"price_id": priceID, "quantity": 1},
		},
		"collection_mode": "automatic",
	}
	resp, err := paddleCall("POST", "/transactions", payload)
	if err != nil {
		return "", "", err
	}
	if data, ok := resp["data"].(map[string]interface{}); ok {
		if id, ok := data["id"].(string); ok {
			txnID = id
		}
		if cp, ok := data["checkout"].(map[string]interface{}); ok {
			if u, ok := cp["url"].(string); ok {
				checkoutURL = u
			}
		}
	}
	if txnID == "" {
		return "", "", fmt.Errorf("paddle did not return transaction id")
	}
	return txnID, checkoutURL, nil
}

// findCustomerByEmail returns the local customer ID and Paddle ID (if any).
// Used to identify accounts by email — the primary lookup.
func findCustomerByEmail(email string) (ourID, paddleID string, found bool) {
	row := corpDB.QueryRow(`SELECT id, COALESCE(paddle_id,'') FROM customers WHERE email = ? LIMIT 1`, email)
	if err := row.Scan(&ourID, &paddleID); err != nil {
		return "", "", false
	}
	return ourID, paddleID, true
}

// --- private helpers ---

func tlwInsert(table string, data map[string]interface{}) error {
	cols := []string{}
	placeholders := []string{}
	values := []interface{}{}
	for k, v := range data {
		if v == nil {
			continue
		}
		cols = append(cols, k)
		placeholders = append(placeholders, "?")
		values = append(values, v)
	}
	stmt := fmt.Sprintf("INSERT INTO %s (%s) VALUES (%s)",
		table, strings.Join(cols, ","), strings.Join(placeholders, ","))
	_, err := corpDB.Exec(stmt, values...)
	return err
}

func paddleCall(method, endpoint string, payload map[string]interface{}) (map[string]interface{}, error) {
	url := paddleBaseURL() + endpoint
	body, _ := json.Marshal(payload)
	req, err := http.NewRequest(method, url, bytes.NewBuffer(body))
	if err != nil {
		return nil, err
	}
	req.Header.Set("Authorization", "Bearer "+paddleAPIKey)
	req.Header.Set("Content-Type", "application/json")
	client := &http.Client{Timeout: 30 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	respBody, _ := io.ReadAll(resp.Body)
	if resp.StatusCode >= 400 {
		return nil, fmt.Errorf("paddle %s %s -> %d: %s", method, endpoint, resp.StatusCode, string(respBody))
	}
	var result map[string]interface{}
	json.Unmarshal(respBody, &result)
	return result, nil
}

func extractPaddleID(resp map[string]interface{}) string {
	if data, ok := resp["data"].(map[string]interface{}); ok {
		if id, ok := data["id"].(string); ok {
			return id
		}
	}
	return ""
}

func firstNonEmpty(vals ...interface{}) interface{} {
	for _, v := range vals {
		if v != nil && v != "" {
			return v
		}
	}
	return ""
}