import { existsSync, readFileSync } from "node:fs";
import { isAbsolute, join, relative } from "node:path";
import type { ActiveRun } from "./types.ts";
import { isPathInsideWorkspace } from "../platform/path.ts";

/**
 * @deprecated Write postcondition checks. Source write blocking is now handled by
 * V2 SourceWritePolicy via GateRunner pre-write checkpoint.
 * This module remains for backward-compatible file existence and template checks.
 */

export type ToolPostconditionStatus = "passed" | "blocked" | "not-applicable";

export interface ToolPostconditionInput {
	cwd: string;
	toolName: string;
	path?: string;
	run?: ActiveRun;
	expected?: "write-file" | "read-file" | "verify-evidence";
}

export interface ToolPostconditionResult {
	status: ToolPostconditionStatus;
	reason: string;
	checks: string[];
}

export function evaluateToolPostcondition(input: ToolPostconditionInput): ToolPostconditionResult {
	if (!input.expected && input.toolName !== "write" && input.toolName !== "edit" && input.toolName !== "read") {
		return { status: "not-applicable", reason: "该工具无 KCode 后置条件。", checks: [] };
	}
	if ((input.toolName === "write" || input.toolName === "edit" || input.expected === "write-file") && input.path) {
		return evaluateWritePostcondition(input);
	}
	if ((input.toolName === "read" || input.expected === "read-file") && input.path) {
		return evaluateReadPostcondition(input);
	}
	return { status: "not-applicable", reason: "缺少可校验路径或预期。", checks: [] };
}

function evaluateWritePostcondition(input: ToolPostconditionInput): ToolPostconditionResult {
	const checks: string[] = [];
	const path = input.path!;
	const resolved = resolvePath(input.cwd, path);
	checks.push("path-present");
	if (!isPathInsideWorkspace(input.cwd, resolved)) {
		return { status: "blocked", reason: `写入后置条件失败：路径不在当前工作区内：${path}`, checks };
	}
	checks.push("inside-workspace");
	// Source write blocking delegated to V2 GateRunner pre-write checkpoint
	if (!existsSync(resolved)) {
		return { status: "blocked", reason: `写入后置条件失败：目标文件不存在：${path}`, checks };
	}
	checks.push("file-exists");
	const content = safeRead(resolved);
	if (content !== undefined && hasTemplatePlaceholder(content)) {
		return { status: "blocked", reason: "写入后置条件失败：文件仍包含模板占位内容。", checks };
	}
	checks.push("no-template-placeholder");
	return { status: "passed", reason: "写入后置条件通过。", checks };
}

function evaluateReadPostcondition(input: ToolPostconditionInput): ToolPostconditionResult {
	const checks: string[] = [];
	const path = input.path!;
	checks.push("path-present");
	const resolved = resolvePath(input.cwd, path);
	if (!existsSync(resolved)) {
		return { status: "blocked", reason: `读取后置条件失败：文件不存在：${path}`, checks };
	}
	checks.push("file-exists");
	const relativePath = isAbsolute(path) ? relative(input.cwd, path) : path;
	if (/^\.\./.test(relativePath.replace(/\\/g, "/"))) {
		return { status: "blocked", reason: `读取后置条件失败：读取目标位于工作区外：${path}`, checks };
	}
	checks.push("inside-workspace");
	return { status: "passed", reason: "读取后置条件通过。", checks };
}

function resolvePath(cwd: string, path: string): string {
	return isAbsolute(path) ? path : join(cwd, path);
}

function safeRead(path: string): string | undefined {
	try {
		return readFileSync(path, "utf8");
	} catch {
		return undefined;
	}
}

function hasTemplatePlaceholder(content: string): boolean {
	return /TODO|TBD|待确认|按实际环境|your[-_ ]?(form|field|token|url)|示例代码|sample only/i.test(content);
}