package config

import (
	"fmt"
	"strconv"
)

type serverOverride func(*serverFile, string) error
type clientOverride func(*clientFile, string) error

// These registries are the authority used later to generate daemon flag
// bindings. A value is applied only when its key is present in the caller map.
var serverOverrideRegistry = map[string]serverOverride{
	"server.data_dir":           func(c *serverFile, v string) error { c.Server.DataDir = v; return nil },
	"server.agent_listen":       func(c *serverFile, v string) error { c.Server.AgentListen = v; return nil },
	"server.agent_path":         func(c *serverFile, v string) error { c.Server.AgentPath = v; return nil },
	"server.control_socket":     func(c *serverFile, v string) error { c.Server.ControlSocket = v; return nil },
	"server.shutdown_grace":     func(c *serverFile, v string) error { c.Server.ShutdownGrace = v; return nil },
	"json_rpc.enabled":          func(c *serverFile, v string) error { return parseBoolOverride(v, &c.JSONRPC.Enabled) },
	"json_rpc.listen":           func(c *serverFile, v string) error { c.JSONRPC.Listen = v; return nil },
	"queue.default_ttl":         func(c *serverFile, v string) error { c.Queue.DefaultTTL = v; return nil },
	"queue.max_per_client":      func(c *serverFile, v string) error { return parseUint32Override(v, &c.Queue.MaxPerClient) },
	"queue.max_server":          func(c *serverFile, v string) error { return parseUint32Override(v, &c.Queue.MaxServer) },
	"protocol.heartbeat_idle":   func(c *serverFile, v string) error { c.Protocol.HeartbeatIdle = v; return nil },
	"protocol.liveness_timeout": func(c *serverFile, v string) error { c.Protocol.LivenessTimeout = v; return nil },
	"protocol.takeover_ttl":     func(c *serverFile, v string) error { c.Protocol.TakeoverTTL = v; return nil },
	"observability.listen":      func(c *serverFile, v string) error { c.Observability.Listen = v; return nil },
	"observability.log_level":   func(c *serverFile, v string) error { c.Observability.LogLevel = v; return nil },
	"observability.log_format":  func(c *serverFile, v string) error { c.Observability.LogFormat = v; return nil },
}

var clientOverrideRegistry = map[string]clientOverride{
	"client.server_url":           func(c *clientFile, v string) error { c.Client.ServerURL = v; return nil },
	"client.state_dir":            func(c *clientFile, v string) error { c.Client.StateDir = v; return nil },
	"client.client_id":            func(c *clientFile, v string) error { c.Client.ClientID = v; return nil },
	"client.daemon_cwd":           func(c *clientFile, v string) error { c.Client.DaemonCWD = v; return nil },
	"client.max_running_commands": func(c *clientFile, v string) error { return parseUint32Override(v, &c.Client.MaxRunningCommands) },
	"client.max_queued_commands":  func(c *clientFile, v string) error { return parseUint32Override(v, &c.Client.MaxQueuedCommands) },
	"client.shutdown_grace":       func(c *clientFile, v string) error { c.Client.ShutdownGrace = v; return nil },
	"tls.ca_file":                 func(c *clientFile, v string) error { c.TLS.CAFile = v; return nil },
	"tls.server_name":             func(c *clientFile, v string) error { c.TLS.ServerName = v; return nil },
	"shells.default_unix":         func(c *clientFile, v string) error { c.Shells.DefaultUnix = v; return nil },
	"shells.default_windows":      func(c *clientFile, v string) error { c.Shells.DefaultWindows = v; return nil },
	"network.reconnect_initial":   func(c *clientFile, v string) error { c.Network.ReconnectInitial = v; return nil },
	"network.reconnect_max":       func(c *clientFile, v string) error { c.Network.ReconnectMax = v; return nil },
	"observability.listen":        func(c *clientFile, v string) error { c.Observability.Listen = v; return nil },
	"observability.log_level":     func(c *clientFile, v string) error { c.Observability.LogLevel = v; return nil },
	"observability.log_format":    func(c *clientFile, v string) error { c.Observability.LogFormat = v; return nil },
	"observability.log_file":      func(c *clientFile, v string) error { c.Observability.LogFile = v; return nil },
}

func applyServerOverrides(config *serverFile, overrides map[string]string) error {
	for key, value := range overrides {
		setter, exists := serverOverrideRegistry[key]
		if !exists {
			return fmt.Errorf("unknown server flag override %q", key)
		}
		if err := setter(config, value); err != nil {
			return fmt.Errorf("server flag override %s: %w", key, err)
		}
	}
	return nil
}

func applyClientOverrides(config *clientFile, overrides map[string]string) error {
	for key, value := range overrides {
		setter, exists := clientOverrideRegistry[key]
		if !exists {
			return fmt.Errorf("unknown client flag override %q", key)
		}
		if err := setter(config, value); err != nil {
			return fmt.Errorf("client flag override %s: %w", key, err)
		}
	}
	return nil
}

func parseBoolOverride(value string, target *bool) error {
	parsed, err := strconv.ParseBool(value)
	if err != nil {
		return err
	}
	*target = parsed
	return nil
}

func parseUint32Override(value string, target *uint32) error {
	parsed, err := strconv.ParseUint(value, 10, 32)
	if err != nil {
		return err
	}
	*target = uint32(parsed)
	return nil
}