package app

import (
	"slices"
	"time"

	"finance-duck/internal/banking"
	"finance-duck/internal/domain"
)

const defaultHistoryMonths = 12

type authorization struct {
	Expires       time.Time
	Institution   string
	Country       string
	HistoryMonths int
}
type Consent struct {
	Institution    string `json:"institution"`
	Country        string `json:"country"`
	HistoryMonths  int    `json:"history_months"`
	Error          string `json:"error,omitempty"`
	NeedsReconnect bool   `json:"needs_reconnect"`
}
type Connection struct {
	AccountID     string `json:"account_id"`
	Institution   string `json:"institution"`
	Country       string `json:"country"`
	HistoryMonths int    `json:"history_months"`
	Status        string `json:"status"`
	ValidUntil    string `json:"valid_until"`
	Error         string `json:"error"`
}

func (c Consent) historyMonths() int {
	if c.HistoryMonths == 0 {
		return defaultHistoryMonths
	}
	return c.HistoryMonths
}

func (a *App) connections(d domain.Dataset) []Connection {
	out := make([]Connection, 0, len(d.Accounts))
	for _, account := range d.Accounts {
		c := Connection{AccountID: account.ID, Institution: account.Institution, Country: "DE", HistoryMonths: defaultHistoryMonths, Status: "local"}
		if account.ExternalAccountID != "" {
			c.Status = "reconnect_required"
			c.Error = "No saved bank consent; reconnect this account"
		}
		for _, session := range a.ops.Sessions {
			for _, linked := range session.Accounts {
				if linked.ID != account.ID {
					continue
				}
				meta := a.ops.Consents[session.ID]
				c.HistoryMonths = meta.historyMonths()
				if meta.Institution != "" {
					c.Institution = meta.Institution
				}
				if meta.Country != "" {
					c.Country = meta.Country
				}
				c.ValidUntil = session.ValidUntil
				c.Error = meta.Error
				c.Status = "connected"
				expiry, err := time.Parse(time.RFC3339, session.ValidUntil)
				if meta.NeedsReconnect || err != nil || !expiry.After(time.Now()) {
					c.Status = "reconnect_required"
					if c.Error == "" {
						c.Error = "Bank consent expired; reconnect to resume automatic imports"
					}
				} else if meta.Error != "" {
					c.Status = "error"
				}
			}
		}
		out = append(out, c)
	}
	return out
}

func copySessions(sessions []banking.Session) []banking.Session {
	out := append([]banking.Session{}, sessions...)
	for i := range out {
		out[i].Accounts = slices.Clone(out[i].Accounts)
	}
	return out
}