// Package model defines the persisted data structures for scientific-surfing.
package model

import (
	"fmt"
	"path/filepath"
)

// SubscriptionStatus mirrors Python's SubscriptionStatus(str, Enum).
type SubscriptionStatus string

const (
	StatusActive   SubscriptionStatus = "active"
	StatusInactive SubscriptionStatus = "inactive"
)

// Subscription is a single clash RSS subscription entry.
type Subscription struct {
	Name        string             `yaml:"name"`
	URL         string             `yaml:"url"`
	Status      SubscriptionStatus `yaml:"status"`
	LastRefresh *Time              `yaml:"last_refresh"`
	FileSize    *int64             `yaml:"file_size"`
	StatusCode  *int               `yaml:"status_code"`
	// int64, not uint64: this Go implementation's own fnv64a hash (see
	// stableHash in the subscription package) fits either way, but the
	// original Python implementation's builtin hash() is a signed 64-bit
	// value and is frequently negative — existing subscriptions.yaml files
	// written by it must still parse.
	ContentHash *int64  `yaml:"content_hash"`
	LastError   *string `yaml:"last_error"`
}

// NewSubscription creates a subscription defaulting to inactive, matching the
// Pydantic model's field defaults.
func NewSubscription(name, url string) *Subscription {
	return &Subscription{
		Name:   name,
		URL:    url,
		Status: StatusInactive,
	}
}

// GetFilePath returns the on-disk path for the downloaded subscription content.
func (s *Subscription) GetFilePath(configDir string) string {
	return filepath.Join(configDir, "subscriptions", s.Name+".yml")
}

// SubscriptionsData is the full persisted collection of subscriptions.
type SubscriptionsData struct {
	Subscriptions map[string]*Subscription `yaml:"subscriptions"`
}

// NewSubscriptionsData returns an empty, ready-to-use collection.
func NewSubscriptionsData() *SubscriptionsData {
	return &SubscriptionsData{Subscriptions: make(map[string]*Subscription)}
}

// GetActiveSubscription returns the currently active subscription, if any.
func (d *SubscriptionsData) GetActiveSubscription() *Subscription {
	for _, sub := range d.Subscriptions {
		if sub.Status == StatusActive {
			return sub
		}
	}
	return nil
}

// SetActive marks name as active and deactivates all others. Returns false if
// name does not exist.
func (d *SubscriptionsData) SetActive(name string) bool {
	if _, ok := d.Subscriptions[name]; !ok {
		return false
	}
	for subName, sub := range d.Subscriptions {
		if subName == name {
			sub.Status = StatusActive
		} else {
			sub.Status = StatusInactive
		}
	}
	return true
}

// AddSubscription adds a new subscription, activating it if it's the first one.
func (d *SubscriptionsData) AddSubscription(name, url string) *Subscription {
	sub := NewSubscription(name, url)
	if len(d.Subscriptions) == 0 {
		sub.Status = StatusActive
	}
	d.Subscriptions[name] = sub
	return sub
}

// RemoveSubscription deletes a subscription by name. Returns false if it
// doesn't exist.
func (d *SubscriptionsData) RemoveSubscription(name string) bool {
	if _, ok := d.Subscriptions[name]; !ok {
		return false
	}
	delete(d.Subscriptions, name)
	return true
}

// RenameSubscription renames oldName to newName. Returns false if oldName is
// missing or newName is already taken.
func (d *SubscriptionsData) RenameSubscription(oldName, newName string) bool {
	sub, ok := d.Subscriptions[oldName]
	if !ok {
		return false
	}
	if _, taken := d.Subscriptions[newName]; taken {
		return false
	}
	delete(d.Subscriptions, oldName)
	sub.Name = newName
	d.Subscriptions[newName] = sub
	return true
}

// SetSubscriptionURL updates the URL for an existing subscription.
func (d *SubscriptionsData) SetSubscriptionURL(name, url string) bool {
	sub, ok := d.Subscriptions[name]
	if !ok {
		return false
	}
	sub.URL = url
	return true
}

// ValidationError is returned by Validate methods, mirroring pydantic's
// ValueError-raising validators.
type ValidationError struct {
	Field   string
	Message string
}

func (e *ValidationError) Error() string {
	return fmt.Sprintf("%s: %s", e.Field, e.Message)
}