package config

import (
	"os"
	"strconv"
	"strings"
	"time"
)

// Account describes a Fio bank account.
type Account struct {
	IBAN     string // e.g. "CZ0820100000002502035405"
	AcctNum  string // bare account number, e.g. "2502035405"
	TokenEnv string // env var name holding the optional Fio API token
	Primary  bool   // true for the account QR codes default to
}

// LoadedAccount is an Account with its token resolved from the environment.
type LoadedAccount struct {
	Account
	Token string // value of os.Getenv(Account.TokenEnv); empty → transparent-scraper path
}

// Accounts is the hardcoded list of Fio bank accounts to sync from.
// The first entry with Primary=true is used for QR codes.
// Tokens are loaded at runtime from each account's TokenEnv.
var Accounts = []Account{
	{IBAN: "CZ0820100000002502035405", AcctNum: "2502035405", TokenEnv: "FIO_API_TOKEN_NEW", Primary: true},
	{IBAN: "CZ8520100000002800359168", AcctNum: "2800359168", TokenEnv: "FIO_API_TOKEN_OLD"},
}

// Google Sheets IDs — change in code if sheets change (not from env).
const (
	AttendanceSheetID = "1E2e_gT_K5AwSRCDLDTa2UetZTkHmBOcz0kFbBUNUNBA"
	PaymentsSheetID   = "1Om0YPoDVCH5cV8BrNz5LG5eR5MMU05ypQC7UMN1xn_Y"

	// Both attendance tabs live in the same Google Spreadsheet (AttendanceSheetID).
	// The original adult and junior attendance data lives in separate source spreadsheets,
	// but is collected into this one sheet via IMPORTRANGE — one tab per group.
	// Tabs are identified by the gid= query param in the CSV export URL.
	AttendanceAdultSheetGID = "0"          // gid=0 — adult practices tab (IMPORTRANGE'd)
	JuniorSheetGID          = "1213318614" // gid=1213318614 — junior practices tab (IMPORTRANGE'd)
)

// CacheSheetMap mirrors scripts/config.py CACHE_SHEET_MAP.
// Maps a cache key to the Google Sheet ID whose Drive modifiedTime gates it.
// Both attendance keys map to the same spreadsheet — different tabs, one Drive file.
var CacheSheetMap = map[string]string{
	"attendance_regular":    AttendanceSheetID,
	"attendance_juniors":    AttendanceSheetID,
	"exceptions_dict":       PaymentsSheetID,
	"payments_transactions": PaymentsSheetID,
}

// Config holds all runtime configuration loaded from environment variables.
// Mirrors scripts/config.py.
type Config struct {
	CredentialsPath  string
	QRAccount        string          // IBAN of the primary account used for QR codes
	LoadedAccounts   []LoadedAccount // all accounts to sync, tokens resolved from env
	CacheDir         string
	CacheTTL         time.Duration
	CacheAPICheckTTL time.Duration
	DriveTimeout     time.Duration
	LogLevel         string
	ServerAddr       string
}

// Load reads configuration from the environment, applying defaults that
// match the Python side.
func Load() Config {
	loaded := make([]LoadedAccount, len(Accounts))
	var qrAccount string
	for i, a := range Accounts {
		loaded[i] = LoadedAccount{Account: a, Token: os.Getenv(a.TokenEnv)}
		if a.Primary {
			qrAccount = a.IBAN
		}
	}
	return Config{
		CredentialsPath:  env("CREDENTIALS_PATH", ".secret/fuj-management-bot-credentials.json"),
		QRAccount:        qrAccount,
		LoadedAccounts:   loaded,
		CacheDir:         env("CACHE_DIR", "tmp/go"),
		CacheTTL:         envDuration("CACHE_TTL_SECONDS", 300),
		CacheAPICheckTTL: envDuration("CACHE_API_CHECK_TTL_SECONDS", 300),
		DriveTimeout:     envDuration("DRIVE_TIMEOUT_SECONDS", 10),
		LogLevel:         env("LOG_LEVEL", "INFO"),
		ServerAddr:       env("SERVER_ADDR", ":8080"),
	}
}

// IBANAccountNum extracts the bare account number from a Czech IBAN.
// "CZ8520100000002800359168" → "2800359168"
// Structure: CZ(2 check)(4 bank code)(16 zero-padded account).
func IBANAccountNum(iban string) string {
	s := strings.ReplaceAll(iban, " ", "")
	if len(s) < 8 {
		return iban
	}
	raw := s[8:] // 16-digit zero-padded account portion
	n := strings.TrimLeft(raw, "0")
	if n == "" {
		return "0"
	}
	return n
}

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

func envDuration(key string, defaultSeconds int) time.Duration {
	if v := os.Getenv(key); v != "" {
		if n, err := strconv.Atoi(v); err == nil && n > 0 {
			return time.Duration(n) * time.Second
		}
	}
	return time.Duration(defaultSeconds) * time.Second
}