// Package api holds the JSON shapes of Steward's REST API, shared by the
// server and the Go client (and so the CLI).
package api

import (
	"encoding/json"
	"time"

	"steward/internal/dhcp4"
	"steward/internal/model"
	"steward/internal/validate"
	"steward/internal/version"
)

// Prefix starts every API path.
const Prefix = "/api/v1"

// ErrorBody is every error response.
type ErrorBody struct {
	Error ErrorInfo `json:"error"`
}

// ErrorInfo describes an error.
type ErrorInfo struct {
	Code     string             `json:"code"`
	Message  string             `json:"message"`
	Problems []validate.Problem `json:"problems,omitempty"`
	// Result is the preview of a refused change.
	Result json.RawMessage `json:"result,omitempty"`
}

// Whoami describes the caller.
type Whoami struct {
	User        *model.User `json:"user"`
	Admin       bool        `json:"admin"`
	Method      string      `json:"method"`
	Permissions []string    `json:"permissions"`
	// TokenID is the token the caller authenticated with (0: none).
	TokenID   int64         `json:"token_id,omitempty"`
	CSRFToken string        `json:"csrf_token,omitempty"`
	Build     version.Build `json:"build"`
}

// Login is the login request.
type Login struct {
	Username string `json:"username"`
	Password string `json:"password"`
}

// PasswordChange changes the caller's password.
type PasswordChange struct {
	Current  string `json:"current"`
	Password string `json:"password"`
}

// OptionInput sets an option: by name ("routers") or number ("43"), with
// a type for numbers the catalog doesn't know (default hex).
type OptionInput struct {
	Option string `json:"option"`
	Value  string `json:"value"`
	Type   string `json:"type,omitempty"`
}

// SettingsInput changes the settings (unset fields stay).
type SettingsInput struct {
	LeaseTime        *int           `json:"lease_time,omitempty"`
	Options          *[]OptionInput `json:"options,omitempty"`
	PingCheck        *bool          `json:"ping_check,omitempty"`
	PingTimeout      *int           `json:"ping_timeout_ms,omitempty"`
	DeclineHold      *int           `json:"decline_hold,omitempty"`
	NotAuthoritative *bool          `json:"not_authoritative,omitempty"`
	// AddressOrder is sequential, reverse or random.
	AddressOrder *string `json:"address_order,omitempty"`
}

// SubnetInput creates or changes a subnet (unset fields stay). Pools are
// "FIRST-LAST" or prefixes, with ":ORDER" for a pool's own address order.
type SubnetInput struct {
	Name      *string   `json:"name,omitempty"`
	Interface *string   `json:"interface,omitempty"`
	Prefix    *string   `json:"prefix,omitempty"`
	Pools     *[]string `json:"pools,omitempty"`
	// PoolOrder is listed or random; AddressOrder sequential, reverse,
	// random or "" (the settings').
	PoolOrder    *string `json:"pool_order,omitempty"`
	AddressOrder *string `json:"address_order,omitempty"`
	// Access is deny-list or allow-list; Allow and Deny replace the
	// lists (entries: a MAC address, aa:bb:cc:* or "id HEX").
	Access    *string              `json:"access,omitempty"`
	Allow     *[]model.ClientMatch `json:"allow,omitempty"`
	Deny      *[]model.ClientMatch `json:"deny,omitempty"`
	LeaseTime *int                 `json:"lease_time,omitempty"`
	Options   *[]OptionInput       `json:"options,omitempty"`
	Disabled  *bool                `json:"disabled,omitempty"`
	Comment   *string              `json:"comment,omitempty"`
}

// ReservationInput creates or changes a reservation (unset fields stay).
type ReservationInput struct {
	MAC      *string        `json:"mac,omitempty"`
	ClientID *string        `json:"client_id,omitempty"`
	IP       *string        `json:"ip,omitempty"`
	Hostname *string        `json:"hostname,omitempty"`
	Options  *[]OptionInput `json:"options,omitempty"`
	// LeaseTime in seconds; 0 for the subnet's.
	LeaseTime *int    `json:"lease_time,omitempty"`
	Disabled  *bool   `json:"disabled,omitempty"`
	Comment   *string `json:"comment,omitempty"`
}

// Subnet is a subnet with its usage.
type Subnet struct {
	*model.Subnet
	Usage Usage `json:"usage"`
}

// Usage counts a subnet's addresses.
type Usage struct {
	// PoolSize is the number of addresses in the pools; Leased of them
	// are held by clients, Declined held back.
	PoolSize int `json:"pool_size"`
	Leased   int `json:"leased"`
	Declined int `json:"declined"`
	// Reservations in the subnet, and how many of them have a lease now.
	Reservations       int `json:"reservations"`
	ReservationsLeased int `json:"reservations_leased"`
}

// Reservation is a reservation with where it is.
type Reservation struct {
	*model.Reservation
	SubnetID   int64  `json:"subnet_id"`
	SubnetName string `json:"subnet"`
	// Lease is the reservation's current lease, if any.
	Lease *Lease `json:"lease,omitempty"`
}

// Lease is a lease with its state now.
type Lease struct {
	*model.Lease
	SubnetName string `json:"subnet"`
	// Reservation is the ID of the reservation for the address, if any.
	Reservation int64 `json:"reservation,omitempty"`
	// ReservedHostname is the reservation's host name.
	ReservedHostname string `json:"reserved_hostname,omitempty"`
}

// MutationResponse answers a configuration change.
type MutationResponse struct {
	Applied   bool               `json:"applied"`
	DryRun    bool               `json:"dry_run,omitempty"`
	HistoryID int64              `json:"history_id,omitempty"`
	Changes   []model.Change     `json:"changes"`
	Warnings  []validate.Problem `json:"warnings,omitempty"`
	// Object is the created or changed object.
	Object json.RawMessage `json:"object,omitempty"`
}

// HostInterface is one of the server's network interfaces.
type HostInterface struct {
	Name      string   `json:"name"`
	Addresses []string `json:"addresses"`
	// Subnets served on it.
	Subnets []int64 `json:"subnets"`
}

// InterfaceStatus says whether DHCP is served on an interface.
type InterfaceStatus struct {
	Name      string    `json:"name"`
	Listening bool      `json:"listening"`
	Error     string    `json:"error,omitempty"`
	Since     time.Time `json:"since"`
	Addresses []string  `json:"addresses"`
	Subnets   []int64   `json:"subnets"`
}

// Status is the dashboard's overview.
type Status struct {
	Build      version.Build      `json:"build"`
	Started    time.Time          `json:"started"`
	Interfaces []InterfaceStatus  `json:"interfaces"`
	Subnets    []Subnet           `json:"subnets"`
	Problems   []validate.Problem `json:"problems"`
	// Leases counts leases by state.
	Leases map[string]int `json:"leases"`
	// Messages counts DHCP messages since the start, by type.
	Messages map[string]uint64 `json:"messages"`
	// PingProblem says why addresses can't be pinged before an offer.
	PingProblem string `json:"ping_problem,omitempty"`
	Database    string `json:"database"`
}

// TokenInput creates a token.
type TokenInput struct {
	Name string `json:"name"`
	// Grants ("leases:read") or a role restrict the token; none: all of
	// the user's permissions.
	Grants    []string   `json:"grants,omitempty"`
	Role      string     `json:"role,omitempty"`
	ExpiresIn string     `json:"expires_in,omitempty"` // 90d, 720h
	ExpiresAt *time.Time `json:"expires_at,omitempty"`
}

// TokenRotation gives a token a new secret. Grace keeps the old secret
// working for a while (up to 7d). The token gets its lifetime again,
// counted from now, unless ExpiresIn or NoExpiry says otherwise.
type TokenRotation struct {
	Grace     string `json:"grace,omitempty"`
	ExpiresIn string `json:"expires_in,omitempty"`
	NoExpiry  bool   `json:"no_expiry,omitempty"`
}

// Token is a token; Secret is only set when it is created.
type Token struct {
	*model.Token
	GrantStrings []string `json:"grant_strings"`
	Secret       string   `json:"secret,omitempty"`
}

// UserInput creates or changes a user.
type UserInput struct {
	Username *string   `json:"username,omitempty"`
	Password *string   `json:"password,omitempty"`
	Admin    *bool     `json:"admin,omitempty"`
	Grants   *[]string `json:"grants,omitempty"`
	Role     *string   `json:"role,omitempty"`
	Disabled *bool     `json:"disabled,omitempty"`
	Comment  *string   `json:"comment,omitempty"`
}

// User is a user with grants written out.
type User struct {
	*model.User
	GrantStrings []string `json:"grant_strings"`
}

// OptionDef is an option of the catalog.
type OptionDef struct {
	Code   int    `json:"code"`
	Name   string `json:"name"`
	Type   string `json:"type"`
	Help   string `json:"help"`
	Common bool   `json:"common,omitempty"`
}

// Catalog lists the options Steward knows, the value types and the codes
// that can't be set.
type Catalog struct {
	Options  []OptionDef         `json:"options"`
	Types    []string            `json:"types"`
	Reserved map[int]string      `json:"reserved"`
	Roles    map[string][]string `json:"roles"`
}

// Event is a DHCP message in or out.
type Event struct {
	Time      time.Time `json:"time"`
	Interface string    `json:"interface"`
	Type      string    `json:"type"`
	MAC       string    `json:"mac"`
	IP        string    `json:"ip,omitempty"`
	Hostname  string    `json:"hostname,omitempty"`
	Detail    string    `json:"detail,omitempty"`
	// ID numbers the events since stewardd started.
	ID uint64 `json:"id"`
	// Direction is "in" for a client's message, "out" for Steward's
	// answer, "" for an event of Steward's own (CONFLICT, NO ADDRESS).
	Direction string `json:"direction,omitempty"`
	ClientID  string `json:"client_id,omitempty"`
	// SubnetID is the subnet that refused a client (DENIED).
	SubnetID int64 `json:"subnet_id,omitempty"`
	// Fields and Options are the message, in words (GET /events/{id}, or
	// ?details=1).
	Fields  []dhcp4.Field `json:"fields,omitempty"`
	Options []dhcp4.Field `json:"options,omitempty"`
}

// ImportResult reports a Kea import.
type ImportResult struct {
	MutationResponse
	Leases  int      `json:"leases"`
	Notes   []string `json:"notes"`
	Skipped []string `json:"skipped"`
}

// CertStep is one step of the preflight check.
type CertStep struct {
	Name   string `json:"name"`
	Status string `json:"status"` // ok, fail, warn, skip
	Detail string `json:"detail"`
	// Queries are the DNS questions asked, as dig commands.
	Queries []string `json:"queries,omitempty"`
}

// CertCheck is the result of a preflight check: can Steward publish its
// challenge through Jarl, and does the internet see it?
type CertCheck struct {
	Time   time.Time  `json:"time"`
	Domain string     `json:"domain"`
	OK     bool       `json:"ok"`
	Steps  []CertStep `json:"steps"`
}

// CertStatus describes the certificate, for the API and the dashboard.
type CertStatus struct {
	Domain    string     `json:"domain"`
	Directory string     `json:"directory"`
	Staging   bool       `json:"staging"`
	State     string     `json:"state"` // none, ok, working, error
	NotBefore *time.Time `json:"not_before,omitempty"`
	NotAfter  *time.Time `json:"not_after,omitempty"`
	Issuer    string     `json:"issuer,omitempty"`
	// IssuedBy is the directory the current certificate came from (it may
	// differ from Directory until the next renewal).
	IssuedBy    string     `json:"issued_by,omitempty"`
	RenewAt     *time.Time `json:"renew_at,omitempty"`
	LastError   string     `json:"last_error,omitempty"`
	LastAttempt *time.Time `json:"last_attempt,omitempty"`
	NextAttempt *time.Time `json:"next_attempt,omitempty"`
	Check       *CertCheck `json:"check,omitempty"`
}

// CertificateResponse is GET /certificate.
type CertificateResponse struct {
	// Configured is false when tls.acme is off.
	Configured bool `json:"configured"`
	// Source is acme, file or none.
	Source string      `json:"source"`
	Status *CertStatus `json:"status,omitempty"`
}