// Package ledger provides a client for aamos-ledger integration.
// One proxy method, not six copies. Linus-style.
package ledger

import (
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"os"
	"time"
)

var baseURL = getEnv("LEDGER_URL", "http://localhost:3250")

func getEnv(key, fallback string) string {
	if v := os.Getenv(key); v != "" {
		return v
	}
	return fallback
}

// Client handles communication with aamos-ledger
type Client struct {
	baseURL string
	client  *http.Client
}

// NewClient creates a new ledger client
func NewClient() *Client {
	return &Client{
		baseURL: baseURL,
		client:  &http.Client{Timeout: 10 * time.Second},
	}
}

// Get proxies a GET request to the ledger and returns the JSON response.
// This replaces 6 identical methods with one.
func (c *Client) Get(ctx context.Context, path string) (map[string]interface{}, error) {
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, c.baseURL+path, nil)
	if err != nil {
		return nil, fmt.Errorf("create request: %w", err)
	}

	resp, err := c.client.Do(req)
	if err != nil {
		return nil, fmt.Errorf("ledger unavailable: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("ledger error: status %d", resp.StatusCode)
	}

	var result map[string]interface{}
	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
		return nil, fmt.Errorf("decode error: %w", err)
	}

	return result, nil
}

// Handler wraps the client for HTTP handlers
type Handler struct {
	client *Client
}

// NewHandler creates a new ledger HTTP handler
func NewHandler() *Handler {
	return &Handler{client: NewClient()}
}

// Proxy handles any ledger endpoint with a single method
func (h *Handler) Proxy(w http.ResponseWriter, r *http.Request, ledgerPath string) {
	result, err := h.client.Get(r.Context(), ledgerPath)
	if err != nil {
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusServiceUnavailable)
		json.NewEncoder(w).Encode(map[string]string{"error": err.Error()})
		return
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(result)
}

// Convenience methods that use Proxy internally
func (h *Handler) GetBalanceSheet(w http.ResponseWriter, r *http.Request) {
	h.Proxy(w, r, "/api/ledger/reports/balance")
}

func (h *Handler) GetIncomeStatement(w http.ResponseWriter, r *http.Request) {
	h.Proxy(w, r, "/api/ledger/reports/income")
}

func (h *Handler) GetMomsReport(w http.ResponseWriter, r *http.Request) {
	h.Proxy(w, r, "/api/ledger/tax/moms")
}

func (h *Handler) GetAccounts(w http.ResponseWriter, r *http.Request) {
	h.Proxy(w, r, "/api/ledger/accounts")
}

func (h *Handler) GetInvoices(w http.ResponseWriter, r *http.Request) {
	h.Proxy(w, r, "/api/ledger/invoices")
}