// Package dav holds code shared by the CalDAV and CardDAV checkers:
// discovery, OPTIONS probing, PROPFIND helpers, and report rendering.
package dav

import "time"

// Kind is carried end-to-end through a run so shared helpers branch on it
// rather than duplicating per-protocol code.
type Kind string

const (
	KindCalDAV  Kind = "caldav"
	KindCardDAV Kind = "carddav"
)

// ServiceName returns the RFC 6764 SRV label, with the leading "_" but
// without the "_tcp" suffix.
func (k Kind) ServiceName(secure bool) string {
	switch k {
	case KindCalDAV:
		if secure {
			return "_caldavs"
		}
		return "_caldav"
	case KindCardDAV:
		if secure {
			return "_carddavs"
		}
		return "_carddav"
	}
	return ""
}

func (k Kind) WellKnownPath() string {
	return "/.well-known/" + string(k)
}

// RequiredCapability is the DAV: header token a compliant server must
// advertise.
func (k Kind) RequiredCapability() string {
	switch k {
	case KindCalDAV:
		return "calendar-access"
	case KindCardDAV:
		return "addressbook"
	}
	return ""
}

// Observation is what each checker persists. Scheduling is CalDAV-only and
// left nil for CardDAV.
type Observation struct {
	Kind           Kind              `json:"kind"`
	Domain         string            `json:"domain"`
	HasCredentials bool              `json:"has_credentials"`
	Discovery      DiscoveryResult   `json:"discovery"`
	Transport      TransportResult   `json:"transport"`
	Options        OptionsResult     `json:"options"`
	Principal      PrincipalResult   `json:"principal"`
	HomeSet        HomeSetResult     `json:"home_set"`
	Collections    CollectionsResult `json:"collections"`
	Report         ReportResult      `json:"report"`
	Scheduling     *SchedulingResult `json:"scheduling,omitempty"`
	CollectedAt    time.Time         `json:"collected_at"`
}

type SRVRecord struct {
	Target   string `json:"target"`
	Port     uint16 `json:"port"`
	Priority uint16 `json:"priority"`
	Weight   uint16 `json:"weight"`
}

// DiscoveryResult records every signal seen during lookup, even on failure,
// so the report can pinpoint which leg of discovery broke.
type DiscoveryResult struct {
	SecureSRV      []SRVRecord `json:"secure_srv,omitempty"`
	PlaintextSRV   []SRVRecord `json:"plaintext_srv,omitempty"`
	SRVError       string      `json:"srv_error,omitempty"`
	TXTPath        string      `json:"txt_path,omitempty"`
	TXTError       string      `json:"txt_error,omitempty"`
	WellKnownURL   string      `json:"well_known_url,omitempty"`
	WellKnownCode  int         `json:"well_known_code,omitempty"`
	WellKnownChain []string    `json:"well_known_chain,omitempty"`
	WellKnownError string      `json:"well_known_error,omitempty"`
	ContextURL     string      `json:"context_url,omitempty"`
	Source         string      `json:"source,omitempty"` // "explicit", "well-known", "srv-txt"
	Error          string      `json:"error,omitempty"`
}

// TransportResult is intentionally minimal: cert validation is out of scope
// here, a dedicated TLS checker owns it.
type TransportResult struct {
	Reached bool   `json:"reached"`
	Error   string `json:"error,omitempty"`
}

type OptionsResult struct {
	StatusCode   int      `json:"status_code"`
	DAVClasses   []string `json:"dav_classes,omitempty"`
	AllowMethods []string `json:"allow_methods,omitempty"`
	AuthSchemes  []string `json:"auth_schemes,omitempty"`
	Server       string   `json:"server,omitempty"`
	Error        string   `json:"error,omitempty"`
}

// PrincipalResult.Skipped is set when no credentials were supplied; the
// rule turns that into StatusUnknown rather than a failure.
type PrincipalResult struct {
	Skipped bool   `json:"skipped,omitempty"`
	URL     string `json:"url,omitempty"`
	Error   string `json:"error,omitempty"`
}

type HomeSetResult struct {
	Skipped bool   `json:"skipped,omitempty"`
	URL     string `json:"url,omitempty"`
	Error   string `json:"error,omitempty"`
}

type CollectionInfo struct {
	Path                  string   `json:"path"`
	Name                  string   `json:"name,omitempty"`
	Description           string   `json:"description,omitempty"`
	MaxResourceSize       int64    `json:"max_resource_size,omitempty"`
	SupportedComponentSet []string `json:"supported_component_set,omitempty"` // CalDAV only
	SupportedAddressData  []string `json:"supported_address_data,omitempty"`  // CardDAV only
}

type CollectionsResult struct {
	Skipped bool             `json:"skipped,omitempty"`
	Items   []CollectionInfo `json:"items,omitempty"`
	Error   string           `json:"error,omitempty"`
}

type ReportResult struct {
	Skipped   bool   `json:"skipped,omitempty"`
	QueryOK   bool   `json:"query_ok,omitempty"`
	ProbePath string `json:"probe_path,omitempty"`
	Error     string `json:"error,omitempty"`
}

// SchedulingResult is CalDAV-only.
type SchedulingResult struct {
	Advertised bool   `json:"advertised"`
	InboxURL   string `json:"inbox_url,omitempty"`
	OutboxURL  string `json:"outbox_url,omitempty"`
	Error      string `json:"error,omitempty"`
}