import { BUILTIN_SLASH_COMMANDS } from "../../packages/coding-agent/src/core/slash-commands.ts";

export type BrowserSlashCommandSurface =
	| "settings"
	| "model"
	| "thinking"
	| "git"
	| "resume"
	| "name"
	| "fork"
	| "compact"
	| "login"
	| "logout"
	| "session"
	| "export"
	// SF command surfaces
	| "sf-status"
	| "sf-visualize"
	| "sf-forensics"
	| "sf-doctor"
	| "sf-skill-health"
	| "sf-knowledge"
	| "sf-capture"
	| "sf-triage"
	| "sf-quick"
	| "sf-history"
	| "sf-undo"
	| "sf-inspect"
	| "sf-prefs"
	| "sf-config"
	| "sf-hooks"
	| "sf-mode"
	| "sf-steer"
	| "sf-export"
	| "sf-cleanup"
	| "sf-queue";

export type BrowserSlashCommandLocalAction =
	| "clear_terminal"
	| "refresh_workspace"
	| "sf_help";

export type BrowserSlashPromptCommandType = "prompt" | "follow_up";

export interface BrowserSlashCommandDispatchOptions {
	isStreaming?: boolean;
}

export type BrowserSlashCommandDispatchResult =
	| {
			kind: "prompt";
			input: string;
			slashCommandName: string | null;
			command: {
				type: BrowserSlashPromptCommandType;
				message: string;
			};
	  }
	| {
			kind: "rpc";
			input: string;
			commandName: string;
			command: { type: "get_state" } | { type: "new_session" };
	  }
	| {
			kind: "surface";
			input: string;
			commandName: string;
			surface: BrowserSlashCommandSurface;
			args: string;
	  }
	| {
			kind: "local";
			input: string;
			commandName: string;
			action: BrowserSlashCommandLocalAction;
	  }
	| {
			kind: "reject";
			input: string;
			commandName: string;
			reason: string;
			guidance: string;
	  }
	| {
			kind: "view-navigate";
			input: string;
			commandName: string;
			view: string;
	  };

export interface BrowserSlashCommandTerminalNotice {
	type: "system" | "error";
	message: string;
}

const BUILTIN_COMMAND_DESCRIPTIONS = new Map(
	BUILTIN_SLASH_COMMANDS.map((command) => [command.name, command.description]),
);
const BUILTIN_COMMAND_NAMES = new Set(BUILTIN_COMMAND_DESCRIPTIONS.keys());

const SURFACE_COMMANDS = new Map<string, BrowserSlashCommandSurface>([
	["settings", "settings"],
	["model", "model"],
	["thinking", "thinking"],
	["git", "git"],
	["resume", "resume"],
	["name", "name"],
	["fork", "fork"],
	["compact", "compact"],
	["login", "login"],
	["logout", "logout"],
	["session", "session"],
	["export", "export"],
]);

// --- SF command dispatch ---

const SF_SURFACE_COMMANDS = new Map<string, BrowserSlashCommandSurface>([
	["status", "sf-status"],
	["visualize", "sf-visualize"],
	["forensics", "sf-forensics"],
	["doctor", "sf-doctor"],
	["skill-health", "sf-skill-health"],
	["knowledge", "sf-knowledge"],
	["capture", "sf-capture"],
	["triage", "sf-triage"],
	["quick", "sf-quick"],
	["history", "sf-history"],
	["undo", "sf-undo"],
	["inspect", "sf-inspect"],
	["prefs", "sf-prefs"],
	["config", "sf-config"],
	["hooks", "sf-hooks"],
	["mode", "sf-mode"],
	["steer", "sf-steer"],
	["cleanup", "sf-cleanup"],
	["queue", "sf-queue"],
]);

const SF_PASSTHROUGH_COMMANDS = new Set<string>([
	"autonomous",
	"next",
	"pause",
	"skip",
	"discuss",
	"run-hook",
	"migrate",
	"remote",
	"new-milestone",
	"init",
]);

export const SF_HELP_TEXT = `Available SF commands:

Workflow:    next · autonomous · autonomous stop · pause · skip · queue · quick · capture · triage
Diagnostics: status · visualize · forensics · doctor · skill-health · inspect
Context:     knowledge · history · undo · discuss
Settings:    model · prefs · config · hooks · mode · steer
Advanced:    export · cleanup · run-hook · migrate · remote

Type /<command> to run. Use /help for this message.`;

function dispatchSFCommand(
	input: string,
	commandName: string,
	args: string,
	options: BrowserSlashCommandDispatchOptions,
): BrowserSlashCommandDispatchResult {
	// `/help` — render inline help locally
	if (commandName === "help") {
		return {
			kind: "local",
			input,
			commandName,
			action: "sf_help",
		};
	}

	// `/visualize` — navigate to the visualizer view directly
	if (commandName === "visualize") {
		return {
			kind: "view-navigate",
			input,
			commandName,
			view: "visualize",
		};
	}

	// Surface-routed commands — open browser-native UI
	const surface = SF_SURFACE_COMMANDS.get(commandName);
	if (surface) {
		return {
			kind: "surface",
			input,
			commandName,
			surface,
			args,
		};
	}

	// Bridge-passthrough commands — let the extension handle them
	if (SF_PASSTHROUGH_COMMANDS.has(commandName)) {
		return {
			kind: "prompt",
			input,
			slashCommandName: commandName,
			command: {
				type: getPromptCommandType(options),
				message: input,
			},
		};
	}

	return buildDeferredBuiltinReject(input, commandName);
}

function parseSlashCommand(
	input: string,
): { name: string; args: string } | null {
	if (!input.startsWith("/")) return null;
	const body = input.slice(1).trim();
	if (!body) return null;

	const firstSpaceIndex = body.search(/\s/);
	if (firstSpaceIndex === -1) {
		return { name: body, args: "" };
	}

	return {
		name: body.slice(0, firstSpaceIndex),
		args: body.slice(firstSpaceIndex + 1).trim(),
	};
}

function getPromptCommandType(
	options: BrowserSlashCommandDispatchOptions,
): BrowserSlashPromptCommandType {
	return options.isStreaming ? "follow_up" : "prompt";
}

function formatBuiltinDescription(commandName: string): string {
	return (
		BUILTIN_COMMAND_DESCRIPTIONS.get(commandName) ??
		"Browser handling is reserved for this built-in command."
	);
}

function buildDeferredBuiltinReject(
	input: string,
	commandName: string,
): BrowserSlashCommandDispatchResult {
	const description = formatBuiltinDescription(commandName);
	return {
		kind: "reject",
		input,
		commandName,
		reason: `/${commandName} is a built-in pi command (${description}) that is not available in the browser yet.`,
		guidance: "It was blocked instead of falling through to the model.",
	};
}

export function isAuthoritativeBuiltinSlashCommand(
	commandName: string,
): boolean {
	return BUILTIN_COMMAND_NAMES.has(commandName);
}

export function dispatchBrowserSlashCommand(
	input: string,
	options: BrowserSlashCommandDispatchOptions = {},
): BrowserSlashCommandDispatchResult {
	const trimmed = input.trim();
	const parsed = parseSlashCommand(trimmed);

	if (trimmed === "/clear") {
		return {
			kind: "local",
			input: trimmed,
			commandName: "clear",
			action: "clear_terminal",
		};
	}

	if (trimmed === "/refresh") {
		return {
			kind: "local",
			input: trimmed,
			commandName: "refresh",
			action: "refresh_workspace",
		};
	}

	if (trimmed === "/state") {
		return {
			kind: "rpc",
			input: trimmed,
			commandName: "state",
			command: { type: "get_state" },
		};
	}

	if (trimmed === "/new-session") {
		return {
			kind: "rpc",
			input: trimmed,
			commandName: "new",
			command: { type: "new_session" },
		};
	}

	if (!parsed) {
		return {
			kind: "prompt",
			input: trimmed,
			slashCommandName: null,
			command: {
				type: getPromptCommandType(options),
				message: trimmed,
			},
		};
	}

	if (parsed.name === "new") {
		return {
			kind: "rpc",
			input: trimmed,
			commandName: "new",
			command: { type: "new_session" },
		};
	}

	if (
		parsed.name === "help" ||
		parsed.name === "visualize" ||
		SF_SURFACE_COMMANDS.has(parsed.name) ||
		SF_PASSTHROUGH_COMMANDS.has(parsed.name)
	) {
		return dispatchSFCommand(trimmed, parsed.name, parsed.args, options);
	}

	const browserSurface = SURFACE_COMMANDS.get(parsed.name);
	if (browserSurface) {
		return {
			kind: "surface",
			input: trimmed,
			commandName: parsed.name,
			surface: browserSurface,
			args: parsed.args,
		};
	}

	if (BUILTIN_COMMAND_NAMES.has(parsed.name)) {
		return buildDeferredBuiltinReject(trimmed, parsed.name);
	}

	return {
		kind: "prompt",
		input: trimmed,
		slashCommandName: parsed.name,
		command: {
			type: getPromptCommandType(options),
			message: trimmed,
		},
	};
}

export function getBrowserSlashCommandTerminalNotice(
	outcome: BrowserSlashCommandDispatchResult,
): BrowserSlashCommandTerminalNotice | null {
	switch (outcome.kind) {
		case "surface":
			return {
				type: "system",
				message: `/${outcome.commandName} is reserved for browser-native handling and was not sent to the model.`,
			};
		case "reject":
			return {
				type: "error",
				message: `${outcome.reason} ${outcome.guidance}`.trim(),
			};
		default:
			return null;
	}
}