package agents

import (
	"context"
	_ "embed"
	"time"

	"github.com/kandev/kandev/internal/agent/mcpconfig"
	"github.com/kandev/kandev/internal/agent/usage"
	"github.com/kandev/kandev/pkg/agent"
)

//go:embed logos/codex_light.svg
var codexACPLogoLight []byte

//go:embed logos/codex_dark.svg
var codexACPLogoDark []byte

const codexACPPkg = "@agentclientprotocol/codex-acp"

var (
	_ Agent            = (*CodexACP)(nil)
	_ PassthroughAgent = (*CodexACP)(nil)
	_ InferenceAgent   = (*CodexACP)(nil)
)

// CodexACP implements Agent for the Agent Client Protocol codex-acp package.
// It speaks the ACP protocol (JSON-RPC 2.0 over stdin/stdout) through the npm
// bridge for OpenAI Codex. Used for A/B comparison against the native Codex agent.
type CodexACP struct {
	StandardPassthrough
}

// codexPassthroughPermSettings maps passthrough-only toggles to @openai/codex CLI
// flags. Not returned from PermissionSettings(): ACP auto-approve uses agentctl
// approval_policy. The legacy --full-auto flag was removed; auto_approve uses
// --ask-for-approval never.
var codexPassthroughPermSettings = map[string]PermissionSetting{
	PermissionKeyAutoApprove: {
		Supported:    true,
		Default:      true,
		Label:        "Auto approve",
		Description:  "Skip command approval prompts (--ask-for-approval never)",
		ApplyMethod:  PermissionApplyMethodCLIFlag,
		CLIFlag:      "--ask-for-approval",
		CLIFlagValue: "never",
	},
}

func NewCodexACP() *CodexACP {
	return &CodexACP{
		StandardPassthrough: StandardPassthrough{
			PermSettings: codexPassthroughPermSettings,
			Cfg: PassthroughConfig{
				Supported:        true,
				Label:            "CLI Passthrough",
				Description:      "Show terminal directly instead of chat interface",
				PassthroughCmd:   NewCommand("npx", "-y", "@openai/codex"),
				ModelFlag:        NewParam("--model", "{model}"),
				IdleTimeout:      3 * time.Second,
				BufferMaxBytes:   DefaultBufferMaxBytes,
				MCPStrategy:      mcpconfig.CodexStrategy{},
				AutoInjectPrompt: true,
				SubmitSequence:   "\r",
			},
		},
	}
}

func (a *CodexACP) ID() string          { return "codex-acp" }
func (a *CodexACP) Name() string        { return "Codex ACP Agent" }
func (a *CodexACP) DisplayName() string { return "Codex" }
func (a *CodexACP) Description() string {
	return "OpenAI Codex coding agent using the Agent Client Protocol bridge."
}
func (a *CodexACP) Enabled() bool     { return true }
func (a *CodexACP) DisplayOrder() int { return 2 }

func (a *CodexACP) Logo(v LogoVariant) []byte {
	if v == LogoDark {
		return codexACPLogoDark
	}
	return codexACPLogoLight
}

func (a *CodexACP) IsInstalled(ctx context.Context) (*DiscoveryResult, error) {
	// Check for the CLI binary on PATH. Auth state is surfaced later by the
	// ACP probe (session/new returns auth_required if the user hasn't logged in).
	result, err := Detect(ctx, WithCommand("codex-acp"), WithCommand("codex"))
	if err != nil {
		return result, err
	}
	result.SupportsMCP = true
	return result, nil
}

func (a *CodexACP) BuildCommand(opts CommandOptions) Command {
	return Cmd("npx", "-y", codexACPPkg).Build()
}

func (a *CodexACP) Runtime() *RuntimeConfig {
	canRecover := true
	return &RuntimeConfig{
		Image:       "kandev/multi-agent",
		Tag:         "latest",
		Cmd:         Cmd("npx", "-y", codexACPPkg).Build(),
		WorkingDir:  "{workspace}",
		RequiredEnv: []string{"OPENAI_API_KEY"},
		Env:         map[string]string{},
		Mounts: []MountTemplate{
			{Source: "{workspace}", Target: "/workspace"},
		},
		ResourceLimits:  ResourceLimits{MemoryMB: 4096, CPUCores: 2.0, Timeout: time.Hour},
		Protocol:        agent.ProtocolACP,
		ProjectSkillDir: ".agents/skills",
		UserSkillDir:    ".codex/skills",
		SessionConfig: SessionConfig{
			NativeSessionResume: true,
			CanRecover:          &canRecover,
			// Use the same SessionDirTemplate pattern every other ACP agent
			// uses; the docker container manager wires this into a kandev-owned
			// per-container session dir, isolated from the host's ~/.codex
			// (which carries host-absolute rollout paths in state.db that
			// don't resolve inside the container).
			SessionDirTemplate: "{home}/.codex",
			SessionDirTarget:   "/root/.codex",
		},
	}
}

func (a *CodexACP) RemoteAuth() *RemoteAuth {
	return &RemoteAuth{
		Methods: []RemoteAuthMethod{
			{
				Type:  "files",
				Label: "Copy auth files",
				SourceFiles: map[string][]string{
					"darwin": {".codex/auth.json", ".codex/config.toml"},
					"linux":  {".codex/auth.json", ".codex/config.toml"},
				},
				TargetRelDir: ".codex",
			},
			{
				Type:   "env",
				EnvVar: "OPENAI_API_KEY",
			},
		},
	}
}

// Verified against `codex --help`: `codex login --device-auth` is the
// dedicated sign-in subcommand. Device-auth prints a code + URL that works
// even when the kandev process can't open a browser (containers, SSH,
// headless dev boxes), and falls back to a local browser flow otherwise.
func (a *CodexACP) LoginCommand() *LoginCommand {
	return &LoginCommand{
		Cmd:         []string{"codex", "login", "--device-auth"},
		Description: "Sign in with your OpenAI account.",
	}
}

// Install both the user-facing OpenAI codex CLI (which `codex login` runs
// against) and the ACP bridge package used for chat sessions.
func (a *CodexACP) InstallScript() string {
	return "npm install -g @openai/codex " + codexACPPkg
}

func (a *CodexACP) BillingType() usage.BillingType { return codexBillingType() }

func (a *CodexACP) PermissionSettings() map[string]PermissionSetting {
	return emptyPermSettings
}

// InferenceConfig returns configuration for one-shot inference using ACP.
func (a *CodexACP) InferenceConfig() *InferenceConfig {
	return &InferenceConfig{
		Supported: true,
		Command:   NewCommand("npx", "-y", codexACPPkg),
	}
}