package config

import (
	"encoding/json"
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"gopkg.in/yaml.v3"
)

// ExtraPort is a TCP or UDP port that the firewall should allow on the WAN interface.
type ExtraPort struct {
	Port     int    `yaml:"port" json:"port"`
	Protocol string `yaml:"protocol,omitempty" json:"protocol,omitempty"` // "tcp" (default) or "udp"
	Label    string `yaml:"label,omitempty" json:"label,omitempty"`
}

// UnmarshalYAML handles both plain integers (legacy: extraPorts: [22]) and structured entries
// (extraPorts: [{port: 22, protocol: tcp, label: SSH}]).
func (p *ExtraPort) UnmarshalYAML(value *yaml.Node) error {
	if value.Kind == yaml.ScalarNode {
		var port int
		if err := value.Decode(&port); err != nil {
			return fmt.Errorf("extraPort: expected integer, got %q", value.Value)
		}
		p.Port = port
		return nil
	}
	type alias ExtraPort
	return value.Decode((*alias)(p))
}

// UnmarshalJSON handles both plain integers (legacy: extraPorts: [22]) and structured entries.
func (p *ExtraPort) UnmarshalJSON(data []byte) error {
	if len(data) > 0 && data[0] != '{' {
		var port int
		if err := json.Unmarshal(data, &port); err != nil {
			return fmt.Errorf("extraPort: expected integer or object, got: %s", data)
		}
		p.Port = port
		return nil
	}
	type alias ExtraPort
	var a alias
	if err := json.Unmarshal(data, &a); err != nil {
		return err
	}
	*p = ExtraPort(a)
	return nil
}

// SplitExtraPorts separates ExtraPorts into TCP and UDP slices.
// Ports with no Protocol or Protocol "tcp" are TCP; Protocol "udp" are UDP.
func SplitExtraPorts(ports []ExtraPort) (tcp []int, udp []int) {
	for _, p := range ports {
		if strings.EqualFold(p.Protocol, "udp") {
			udp = append(udp, p.Port)
		} else {
			tcp = append(tcp, p.Port)
		}
	}
	return
}

// HAProxyCustomRoute defines a custom TCP proxy rule for non-Wild Cloud services
type HAProxyCustomRoute struct {
	Name    string `yaml:"name" json:"name"`
	Port    int    `yaml:"port" json:"port"`
	Backend string `yaml:"backend" json:"backend"`
}

// DHCPStaticLease defines a static DHCP address assignment
type DHCPStaticLease struct {
	MAC      string `yaml:"mac" json:"mac"`
	IP       string `yaml:"ip" json:"ip"`
	Hostname string `yaml:"hostname,omitempty" json:"hostname,omitempty"`
}

// State represents Wild Central's runtime state — operator settings, networking
// configuration, DDNS, DHCP, etc. Persisted in {dataDir}/state.yaml and mutated
// via the API. This is NOT boot-time config (which comes from env vars).
type State struct {
	Operator struct {
		Email string `yaml:"email,omitempty" json:"email,omitempty"`
	} `yaml:"operator,omitempty" json:"operator,omitempty"`
	Cloud struct {
		Central struct {
			Domain string `yaml:"domain,omitempty" json:"domain,omitempty"` // e.g. "central.payne.io"
		} `yaml:"central,omitempty" json:"central,omitempty"`
		Dnsmasq struct {
			IP        string `yaml:"ip,omitempty" json:"ip,omitempty"`
			Interface string `yaml:"interface,omitempty" json:"interface,omitempty"`
			DHCP      struct {
				Enabled      bool              `yaml:"enabled,omitempty" json:"enabled,omitempty"`
				RangeStart   string            `yaml:"rangeStart,omitempty" json:"rangeStart,omitempty"`
				RangeEnd     string            `yaml:"rangeEnd,omitempty" json:"rangeEnd,omitempty"`
				LeaseTime    string            `yaml:"leaseTime,omitempty" json:"leaseTime,omitempty"`
				Gateway      string            `yaml:"gateway,omitempty" json:"gateway,omitempty"`
				StaticLeases []DHCPStaticLease `yaml:"staticLeases,omitempty" json:"staticLeases,omitempty"`
			} `yaml:"dhcp,omitempty" json:"dhcp,omitempty"`
		} `yaml:"dnsmasq,omitempty" json:"dnsmasq,omitempty"`
		HAProxy struct {
			CustomRoutes []HAProxyCustomRoute `yaml:"customRoutes,omitempty" json:"customRoutes,omitempty"`
		} `yaml:"haproxy,omitempty" json:"haproxy,omitempty"`
		Nftables struct {
			Enabled      *bool       `yaml:"enabled,omitempty" json:"enabled,omitempty"`
			WANInterface string      `yaml:"wanInterface,omitempty" json:"wanInterface,omitempty"`
			ExtraPorts   []ExtraPort `yaml:"extraPorts,omitempty" json:"extraPorts,omitempty"`
		} `yaml:"nftables,omitempty" json:"nftables,omitempty"`
		DDNS struct {
			Enabled         bool   `yaml:"enabled,omitempty" json:"enabled,omitempty"`
			Provider        string `yaml:"provider,omitempty" json:"provider,omitempty"`
			IntervalMinutes int    `yaml:"intervalMinutes,omitempty" json:"intervalMinutes,omitempty"`
		} `yaml:"ddns,omitempty" json:"ddns,omitempty"`
	} `yaml:"cloud,omitempty" json:"cloud,omitempty"`
}

// LoadState loads state from the specified path
func LoadState(configPath string) (*State, error) {
	data, err := os.ReadFile(configPath)
	if err != nil {
		return nil, fmt.Errorf("reading config file %s: %w", configPath, err)
	}

	config := &State{}
	if err := yaml.Unmarshal(data, config); err != nil {
		return nil, fmt.Errorf("parsing config file: %w", err)
	}

	return config, nil
}

// SaveState saves the state to the specified path
func SaveState(config *State, configPath string) error {
	// Ensure the directory exists
	if err := os.MkdirAll(filepath.Dir(configPath), 0755); err != nil {
		return fmt.Errorf("creating config directory: %w", err)
	}

	data, err := yaml.Marshal(config)
	if err != nil {
		return fmt.Errorf("marshaling config: %w", err)
	}

	return os.WriteFile(configPath, data, 0644)
}

// IsEmpty checks if the configuration is empty or uninitialized
func (c *State) IsEmpty() bool {
	if c == nil {
		return true
	}

	// Check if essential fields are empty
	return c.Cloud.Central.Domain == "" && c.Operator.Email == ""
}