/**
 * State injection for goal-driven-loop.
 *
 * Reads .agents/goal/GOAL.md and injects goal state into
 * the agent's context via before_agent_start.
 */

import { readFileSync, existsSync } from "node:fs";
import { join } from "node:path";

export interface GoalState {
  goal: string;
  status: "in-progress" | "blocked" | "complete";
  iteration: number;
  totalCriteria: number;
  passedCriteria: number;
  created: string;
  updated: string;
  blocker?: string;
  progressLog: string[];
}

/**
 * Parse GOAL.md frontmatter and body to extract goal state.
 */
export function readGoalState(cwd: string): GoalState | null {
  const goalPath = join(cwd, ".agents", "goal", "GOAL.md");
  if (!existsSync(goalPath)) {
    return null;
  }

  const content = readFileSync(goalPath, "utf-8");

  const frontmatterMatch = content.match(/^---\n([\s\S]*?)\n---/);
  if (!frontmatterMatch) {
    return null;
  }

  const frontmatter = frontmatterMatch[1];
  const goal = extractField(frontmatter, "goal") || "";
  const status =
    (extractField(frontmatter, "status") as GoalState["status"]) ||
    "in-progress";
  const iteration = parseInt(
    extractField(frontmatter, "iteration") || "0",
    10
  );
  const created = extractField(frontmatter, "created") || "";
  const updated = extractField(frontmatter, "updated") || "";

  const criteriaSection = extractSection(content, "Acceptance Criteria");
  const totalCriteria = countCheckboxes(criteriaSection);
  const passedCriteria = countCheckedBoxes(criteriaSection);

  const blockerSection = extractSection(content, "Blocked");
  const blockerRaw = blockerSection.trim() || undefined;
  const blocker = blockerRaw
    ? blockerRaw.replace(/^[-*]\s*/, "").trim() || undefined
    : undefined;

  const progressSection = extractSection(content, "Progress Log");
  const progressLog = extractIterations(progressSection);

  return {
    goal,
    status,
    iteration,
    totalCriteria,
    passedCriteria,
    created,
    updated,
    blocker,
    progressLog,
  };
}

/**
 * Build the injection text for the system prompt or message.
 */
export function buildInjectionText(state: GoalState): string {
  if (state.status === "complete") {
    return `[goal-driven-loop] GOAL COMPLETE
${state.goal}
Final: ${state.passedCriteria}/${state.totalCriteria} criteria passed across ${state.iteration} iterations.
GOAL.md is being cleaned up.`;
  }

  if (state.status === "blocked" && state.blocker) {
    return `[goal-driven-loop] GOAL BLOCKED
${state.goal}
Blocker: ${state.blocker}
Progress: ${state.passedCriteria}/${state.totalCriteria} criteria passed, iteration ${state.iteration}.
Continue by trying a different strategy. If still blocked after 2 attempts, surface to the user.`;
  }

  return `[goal-driven-loop] ACTIVE GOAL
${state.goal}
Progress: ${state.passedCriteria}/${state.totalCriteria} criteria passed, iteration ${state.iteration}
Next step: read .agents/goal/GOAL.md and continue the loop.`;
}

/**
 * Build a continuation prompt for context tension situations.
 */
export function buildContinuationPrompt(state: GoalState): string {
  return `🔄 目标状态已保存至 .agents/goal/GOAL.md
当前进度：${state.passedCriteria}/${state.totalCriteria} criteria 通过，第 ${state.iteration} 轮迭代。`;
}

// ---- helpers ----

function extractField(frontmatter: string, field: string): string | null {
  const match = frontmatter.match(new RegExp(`^${field}:\\s*(.*)$`, "m"));
  if (!match) return null;
  let value = match[1].trim();
  if (
    (value.startsWith('"') && value.endsWith('"')) ||
    (value.startsWith("'") && value.endsWith("'"))
  ) {
    value = value.slice(1, -1);
  }
  return value;
}

function extractSection(content: string, sectionName: string): string {
  const regex = new RegExp(`## ${sectionName}\\n([\\s\\S]*?)(?=\\n## |$)`);
  const match = content.match(regex);
  return match ? match[1] : "";
}

function countCheckboxes(section: string): number {
  return (section.match(/^- \[[ x]\]/gm) || []).length;
}

function countCheckedBoxes(section: string): number {
  return (section.match(/^- \[x\]/gim) || []).length;
}

function extractIterations(section: string): string[] {
  return section.match(/### Iteration \d+/g) || [];
}