// Package config defines the YAML configuration structures for all three
// binaries and loads them from disk. OpenStack credentials are deliberately
// never part of these structs — only the *names* of environment variables
// to read them from — so secrets never land in a config file on disk.
package config

import (
	"fmt"
	"os"

	"gopkg.in/yaml.v3"
)

// ---- control-api ----

type ControlAPI struct {
	Server       ServerConfig        `yaml:"server"`
	Database     DatabaseConfig      `yaml:"database"`
	OpenStack    OpenStackConfig     `yaml:"openstack"`
	Orchestrator OrchestratorConfig  `yaml:"orchestrator"`
	Aggregation  AggregationConfig   `yaml:"aggregation"`
	Validators   []ValidatorConfig   `yaml:"validators"`
	Sites        []SiteConfig        `yaml:"sites"`
	CheckTypes   []CheckTypeConfig   `yaml:"check_types"`
	Targets      map[string][]string `yaml:"targets"`
	Inbound      InboundConfig       `yaml:"inbound_checks"`
	IPAddresses  []string            `yaml:"ip_addresses"`
}

type ServerConfig struct {
	ListenAddr string `yaml:"listen_addr"`
}

type DatabaseConfig struct {
	Path string `yaml:"path"`
}

// OpenStackConfig names the environment variables control-api reads its
// OpenStack admin credential from at startup. Mode "mock" skips all of this
// and uses an in-memory FloatingIPClient instead — used for local dev and
// the offline end-to-end harness.
//
// AuthMethod selects which credential shape is expected in the process
// environment: "token" (default) reads a pre-issued, already
// project-scoped token from TokenEnv and uses it as-is (no renewal — the
// operator reissues and restarts on expiry). "password" reads
// username/password/domain from UsernameEnv/PasswordEnv/UserDomainNameEnv
// and has the client obtain and auto-renew its own token.
type OpenStackConfig struct {
	Mode       string `yaml:"mode"`        // "mock" | "real"
	AuthMethod string `yaml:"auth_method"` // "token" (default) | "password"

	AuthURLEnv   string `yaml:"auth_url_env"`   // default OS_AUTH_URL
	ProjectIDEnv string `yaml:"project_id_env"` // default OS_PROJECT_ID
	RegionEnv    string `yaml:"region_env"`     // default OS_REGION_NAME
	InterfaceEnv string `yaml:"interface_env"`  // default OS_INTERFACE; "" at runtime defaults to "public"

	TokenEnv string `yaml:"token_env"` // default OS_TOKEN — used when auth_method: token

	UsernameEnv       string `yaml:"username_env"`         // default OS_USERNAME — used when auth_method: password
	UserDomainNameEnv string `yaml:"user_domain_name_env"` // default OS_USER_DOMAIN_NAME
	PasswordEnv       string `yaml:"password_env"`         // default OS_PASSWORD
}

type OrchestratorConfig struct {
	PollIntervalSeconds     int `yaml:"poll_interval_seconds"`
	SelfCheckTimeoutSeconds int `yaml:"self_check_timeout_seconds"`
	MaxSelfCheckRetries     int `yaml:"max_self_check_retries"`
	CheckingWindowSeconds   int `yaml:"checking_window_seconds"`
	MaxRetries              int `yaml:"max_retries"`
	LeaseTTLSeconds         int `yaml:"lease_ttl_seconds"`
	HeartbeatTimeoutSeconds int `yaml:"heartbeat_timeout_seconds"`
	// FIPSettleSeconds is only the one-time seed value used the first time
	// control-api starts against an empty database; after that it's
	// managed at runtime via PUT /api/v1/admin/config/orchestrator (or the
	// dashboard's /settings page) and this field is ignored. Zero (no
	// pause) is a valid, backward-compatible default — unlike every other
	// field in this struct, it deliberately gets no nonzero default in
	// LoadControlAPI below.
	FIPSettleSeconds int `yaml:"fip_settle_seconds"`
}

type AggregationConfig struct {
	MissingCountsAsFail bool `yaml:"missing_counts_as_fail"`
}

type ValidatorConfig struct {
	ValidatorID string `yaml:"validator_id"`
	OSPortID    string `yaml:"os_port_id"`
}

type SiteConfig struct {
	SiteID string `yaml:"site_id"`
	Index  int    `yaml:"index"` // any int >= 1, no cap on the number of slots
}

// CheckTypeConfig maps a check type (https, icmp, ssh) to the named target
// groups (keys into ControlAPI.Targets) it should run against. This drives
// the egress/outbound checks the validator-agent performs.
type CheckTypeConfig struct {
	Name    string   `yaml:"name"`
	Enabled bool     `yaml:"enabled"`
	Targets []string `yaml:"targets"`
}

type InboundConfig struct {
	Ports []int `yaml:"ports"`
	ICMP  bool  `yaml:"icmp"`
}

func LoadControlAPI(path string) (*ControlAPI, error) {
	var c ControlAPI
	if err := loadYAML(path, &c); err != nil {
		return nil, err
	}
	if c.Server.ListenAddr == "" {
		c.Server.ListenAddr = ":8080"
	}
	if c.Database.Path == "" {
		c.Database.Path = "control-api.db"
	}
	if c.OpenStack.Mode == "" {
		c.OpenStack.Mode = "mock"
	}
	if c.OpenStack.AuthMethod == "" {
		c.OpenStack.AuthMethod = "token"
	}
	if c.OpenStack.AuthURLEnv == "" {
		c.OpenStack.AuthURLEnv = "OS_AUTH_URL"
	}
	if c.OpenStack.ProjectIDEnv == "" {
		c.OpenStack.ProjectIDEnv = "OS_PROJECT_ID"
	}
	if c.OpenStack.RegionEnv == "" {
		c.OpenStack.RegionEnv = "OS_REGION_NAME"
	}
	if c.OpenStack.InterfaceEnv == "" {
		c.OpenStack.InterfaceEnv = "OS_INTERFACE"
	}
	if c.OpenStack.TokenEnv == "" {
		c.OpenStack.TokenEnv = "OS_TOKEN"
	}
	if c.OpenStack.UsernameEnv == "" {
		c.OpenStack.UsernameEnv = "OS_USERNAME"
	}
	if c.OpenStack.UserDomainNameEnv == "" {
		c.OpenStack.UserDomainNameEnv = "OS_USER_DOMAIN_NAME"
	}
	if c.OpenStack.PasswordEnv == "" {
		c.OpenStack.PasswordEnv = "OS_PASSWORD"
	}
	if c.Orchestrator.PollIntervalSeconds == 0 {
		c.Orchestrator.PollIntervalSeconds = 5
	}
	if c.Orchestrator.SelfCheckTimeoutSeconds == 0 {
		c.Orchestrator.SelfCheckTimeoutSeconds = 60
	}
	if c.Orchestrator.MaxSelfCheckRetries == 0 {
		c.Orchestrator.MaxSelfCheckRetries = 3
	}
	if c.Orchestrator.CheckingWindowSeconds == 0 {
		c.Orchestrator.CheckingWindowSeconds = 120
	}
	if c.Orchestrator.MaxRetries == 0 {
		c.Orchestrator.MaxRetries = 3
	}
	if c.Orchestrator.LeaseTTLSeconds == 0 {
		c.Orchestrator.LeaseTTLSeconds = 180
	}
	if c.Orchestrator.HeartbeatTimeoutSeconds == 0 {
		c.Orchestrator.HeartbeatTimeoutSeconds = 30
	}
	return &c, nil
}

// ---- validator-agent ----

type ValidatorAgent struct {
	ValidatorID         string       `yaml:"validator_id"`
	ControlAPIURL       string       `yaml:"control_api_url"`
	PollIntervalSeconds int          `yaml:"poll_interval_seconds"`
	SelfCheck           SelfCheckCfg `yaml:"self_check"`
	Checks              AgentChecks  `yaml:"checks"`
}

// SelfCheckCfg configures how the agent confirms its egress actually flows
// through the newly assigned floating IP. This must query a resource
// genuinely outside the cloud project: OpenStack only applies floating-IP
// SNAT to traffic leaving via the external/provider network, so any
// in-project resource (including control-api, if it's reachable over the
// project's internal network) would see the validator's private address
// instead — a false negative that never changes. IPEchoURLs are tried in
// order (falling through to the next on error/timeout, not on a genuine
// mismatch) until one returns a parseable IP.
type SelfCheckCfg struct {
	TimeoutSeconds int      `yaml:"timeout_seconds"`
	IPEchoURLs     []string `yaml:"ip_echo_urls"`
}

type AgentChecks struct {
	HTTPSTimeoutSeconds int    `yaml:"https_timeout_seconds"`
	ICMPTimeoutSeconds  int    `yaml:"icmp_timeout_seconds"`
	ICMPCount           int    `yaml:"icmp_count"`
	SSH                 SSHCfg `yaml:"ssh"`
}

type SSHCfg struct {
	Enabled        bool `yaml:"enabled"`
	TimeoutSeconds int  `yaml:"timeout_seconds"`
}

func LoadValidatorAgent(path string) (*ValidatorAgent, error) {
	var c ValidatorAgent
	if err := loadYAML(path, &c); err != nil {
		return nil, err
	}
	if c.PollIntervalSeconds == 0 {
		c.PollIntervalSeconds = 5
	}
	if c.SelfCheck.TimeoutSeconds == 0 {
		c.SelfCheck.TimeoutSeconds = 10
	}
	if len(c.SelfCheck.IPEchoURLs) == 0 {
		c.SelfCheck.IPEchoURLs = []string{"https://api.ipify.org", "https://ifconfig.me/ip"}
	}
	if c.Checks.HTTPSTimeoutSeconds == 0 {
		c.Checks.HTTPSTimeoutSeconds = 10
	}
	if c.Checks.ICMPTimeoutSeconds == 0 {
		c.Checks.ICMPTimeoutSeconds = 5
	}
	if c.Checks.ICMPCount == 0 {
		c.Checks.ICMPCount = 3
	}
	if c.Checks.SSH.TimeoutSeconds == 0 {
		c.Checks.SSH.TimeoutSeconds = 5
	}
	if c.ValidatorID == "" {
		return nil, fmt.Errorf("validator_id is required")
	}
	if c.ControlAPIURL == "" {
		return nil, fmt.Errorf("control_api_url is required")
	}
	return &c, nil
}

// ---- prober ----

type Prober struct {
	SiteID              string       `yaml:"site_id"`
	ControlAPIURL       string       `yaml:"control_api_url"`
	PollIntervalSeconds int          `yaml:"poll_interval_seconds"`
	Checks              ProberChecks `yaml:"checks"`
}

type ProberChecks struct {
	TCPTimeoutSeconds  int `yaml:"tcp_timeout_seconds"`
	ICMPTimeoutSeconds int `yaml:"icmp_timeout_seconds"`
	ICMPCount          int `yaml:"icmp_count"`
}

func LoadProber(path string) (*Prober, error) {
	var c Prober
	if err := loadYAML(path, &c); err != nil {
		return nil, err
	}
	if c.PollIntervalSeconds == 0 {
		c.PollIntervalSeconds = 5
	}
	if c.Checks.TCPTimeoutSeconds == 0 {
		c.Checks.TCPTimeoutSeconds = 5
	}
	if c.Checks.ICMPTimeoutSeconds == 0 {
		c.Checks.ICMPTimeoutSeconds = 5
	}
	if c.Checks.ICMPCount == 0 {
		c.Checks.ICMPCount = 3
	}
	if c.SiteID == "" {
		return nil, fmt.Errorf("site_id is required")
	}
	if c.ControlAPIURL == "" {
		return nil, fmt.Errorf("control_api_url is required")
	}
	return &c, nil
}

// ---- admin-dashboard ----

// AdminDashboard is the config for the 4th binary, cmd/admin-dashboard — a
// stateless, server-rendered web UI over control-api's /api/v1/admin/*
// HTTP API (see docs/DASHBOARD.md). It never talks to the database.
type AdminDashboard struct {
	Server     ServerConfig              `yaml:"server"`
	ControlAPI DashboardControlAPIConfig `yaml:"control_api"`
	Overview   DashboardOverviewConfig   `yaml:"overview"`
}

type DashboardControlAPIConfig struct {
	BaseURL        string `yaml:"base_url"`
	TimeoutSeconds int    `yaml:"timeout_seconds"`
}

// DashboardOverviewConfig configures the overview page's "текущая
// проверка" / "последние N завершённых" summary — see
// docs/DASHBOARD.md#текущая-и-последняя-завершённая-проверка. Both are
// computed fresh on every request from control-api's existing
// status/queue endpoints; there is no persisted "run"/"batch" concept.
type DashboardOverviewConfig struct {
	LastCompletedCount  int `yaml:"last_completed_count"`
	PollIntervalSeconds int `yaml:"poll_interval_seconds"`
}

func LoadAdminDashboard(path string) (*AdminDashboard, error) {
	var c AdminDashboard
	if err := loadYAML(path, &c); err != nil {
		return nil, err
	}
	if c.Server.ListenAddr == "" {
		c.Server.ListenAddr = ":8090"
	}
	if c.ControlAPI.BaseURL == "" {
		return nil, fmt.Errorf("control_api.base_url is required")
	}
	if c.ControlAPI.TimeoutSeconds == 0 {
		c.ControlAPI.TimeoutSeconds = 10
	}
	if c.Overview.LastCompletedCount == 0 {
		c.Overview.LastCompletedCount = 20
	}
	if c.Overview.PollIntervalSeconds == 0 {
		c.Overview.PollIntervalSeconds = 5
	}
	return &c, nil
}

func loadYAML(path string, out interface{}) error {
	data, err := os.ReadFile(path)
	if err != nil {
		return fmt.Errorf("read config %s: %w", path, err)
	}
	if err := yaml.Unmarshal(data, out); err != nil {
		return fmt.Errorf("parse config %s: %w", path, err)
	}
	return nil
}