package handlers

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

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

var ledgerBaseURL = getEnv("LEDGER_URL", "http://172.17.0.1:3250")

// LedgerClient handles communication with aamos-ledger
type LedgerClient struct {
	BaseURL string
}

func NewLedgerClient() *LedgerClient {
	return &LedgerClient{BaseURL: ledgerBaseURL}
}

func (c *LedgerClient) Get(path string) (*http.Response, error) {
	return http.Get(c.BaseURL + path)
}

// LedgerFinanceHandler connects to aamos-ledger for financial data
type LedgerFinanceHandler struct {
	Client *LedgerClient
}

func NewLedgerFinanceHandler() *LedgerFinanceHandler {
	return &LedgerFinanceHandler{Client: NewLedgerClient()}
}

// GetBalanceSheet returns trial balance from ledger
func (h *LedgerFinanceHandler) GetBalanceSheet(w http.ResponseWriter, r *http.Request) {
	period := r.URL.Query().Get("period")
	if period == "" {
		period = time.Now().Format("2006-01")
	}

	resp, err := h.Client.Get("/api/ledger/trial-balance?period=" + period)
	if err != nil || resp.StatusCode != 200 {
		// Fallback to mock data
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(map[string]interface{}{
			"assets": []map[string]interface{}{
				{"account": "1930 - Checkkonto", "amount": 245000},
				{"account": "1940 - Sparkonto", "amount": 500000},
				{"account": "1510 - Kundfordringar", "amount": 125000},
			},
			"liabilities": []map[string]interface{}{
				{"account": "2440 - Leverantörsskulder", "amount": 85000},
				{"account": "2013 - Aktiekapital", "amount": 100000},
			},
			"equity": []map[string]interface{}{
				{"account": "2091 - Balanserad vinst", "amount": 485000},
			},
			"total_assets": 870000,
			"total_liabilities": 185000,
			"total_equity": 685000,
			"period": period,
		})
		return
	}
	defer resp.Body.Close()

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

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

// GetIncomeStatement returns income statement (not yet implemented in ledger)
func (h *LedgerFinanceHandler) GetIncomeStatement(w http.ResponseWriter, r *http.Request) {
	// Return mock data until ledger implements this
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(map[string]interface{}{
		"revenue": 245000,
		"expenses": 180000,
		"net_income": 65000,
		"period": time.Now().Format("2006-01"),
	})
}

// GetMomsReport returns VAT report (not yet implemented in ledger)
func (h *LedgerFinanceHandler) GetMomsReport(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(map[string]interface{}{
		"moms_in": 61250,
		"moms_ut": 35000,
		"moms_att_betala": 26250,
		"period": time.Now().Format("2006-01"),
	})
}

// GetAccounts returns chart of accounts from ledger
func (h *LedgerFinanceHandler) GetAccounts(w http.ResponseWriter, r *http.Request) {
	resp, err := h.Client.Get("/api/v1/accounts")
	if err != nil || resp.StatusCode != 200 {
		// Fallback to mock data
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(map[string]interface{}{
			"accounts": []map[string]interface{}{
				{"id": "1930", "name": "Checkkonto", "type": "asset", "balance": 245000},
				{"id": "1940", "name": "Sparkonto", "type": "asset", "balance": 500000},
				{"id": "1510", "name": "Kundfordringar", "type": "asset", "balance": 125000},
				{"id": "2440", "name": "Leverantörsskulder", "type": "liability", "balance": 85000},
				{"id": "2013", "name": "Aktiekapital", "type": "equity", "balance": 100000},
				{"id": "2091", "name": "Balanserad vinst", "type": "equity", "balance": 485000},
				{"id": "3001", "name": "Försäljning tjänster", "type": "revenue", "balance": 450000},
				{"id": "6100", "name": "Löner", "type": "expense", "balance": 180000},
			},
		})
		return
	}
	defer resp.Body.Close()

	var result map[string]interface{}
	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
		var accounts []map[string]interface{}
		if err := json.NewDecoder(resp.Body).Decode(&accounts); err != nil {
			writeError(w, http.StatusInternalServerError, "decode error")
			return
		}
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(map[string]interface{}{"accounts": accounts})
		return
	}

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

// GetInvoices returns invoices (mock until implemented)
func (h *LedgerFinanceHandler) GetInvoices(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(map[string]interface{}{
		"invoices": []map[string]interface{}{
			{"id": "INV-001", "customer": "Test AB", "amount": 25000, "status": "paid", "due_date": "2026-07-30"},
			{"id": "INV-002", "customer": "Acme Corp", "amount": 45000, "status": "pending", "due_date": "2026-08-15"},
		},
		"total": 2,
	})
}

// GetCashflow returns cashflow (mock until implemented)
func (h *LedgerFinanceHandler) GetCashflow(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(map[string]interface{}{
		"inflow": 320000,
		"outflow": 180000,
		"net": 140000,
		"period": time.Now().Format("2006-01"),
	})
}

// GetBudget returns budget (mock until implemented)
func (h *LedgerFinanceHandler) GetBudget(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(map[string]interface{}{
		"budget": 500000,
		"actual": 245000,
		"remaining": 255000,
		"period": time.Now().Format("2006-01"),
	})
}

// CreateExpense creates an expense (mock until implemented)
func (h *LedgerFinanceHandler) CreateExpense(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(map[string]interface{}{
		"id": "EXP-001",
		"status": "created",
	})
}

// ListExpenses lists expenses (mock until implemented)
func (h *LedgerFinanceHandler) ListExpenses(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(map[string]interface{}{
		"expenses": []map[string]interface{}{
			{"id": "EXP-001", "category": "Boende", "amount": 8500, "date": "2026-07-01"},
			{"id": "EXP-002", "category": "Mat", "amount": 3200, "date": "2026-07-05"},
		},
		"total": 2,
	})
}