/**
 * Artifacts storage for workflow runs.
 *
 * Stores progress, usage, and output artifacts at:
 *   <getAgentDir()>/workflows/<run-id>/
 *
 * Each run directory contains:
 *   progress.json   — WorkflowProgress snapshot
 *   output.md       — Final assembled output
 *   steps/<step-id>.json — Per-step progress and output
 */

import { mkdirSync, writeFileSync, readFileSync, existsSync, readdirSync, rmSync } from "node:fs";
import { join } from "node:path";
import { getAgentDir } from "../../shared/paths.ts";
import {
  WORKFLOWS_DIR_NAME,
  type WorkflowProgress,
  type StepProgress,
} from "./types.ts";

// ── Paths ───────────────────────────────────────────────────────────────────────

/** Root directory for all workflow artifact storage. */
export function workflowsDir(): string {
  return join(getAgentDir(), WORKFLOWS_DIR_NAME);
}

/** Directory for a specific run's artifacts. */
export function runDir(runId: string): string {
  return join(workflowsDir(), runId);
}

/** Path to the progress snapshot for a run. */
function progressPath(runId: string): string {
  return join(runDir(runId), "progress.json");
}

/** Directory for per-step outputs. */
function stepsDir(runId: string): string {
  return join(runDir(runId), "steps");
}

/** Path to a specific step's output file. */
function stepPath(runId: string, stepId: string): string {
  return join(stepsDir(runId), `${stepId.replace(/[^a-zA-Z0-9_-]/g, "_")}.json`);
}

/** Path to the final output file. */
function outputPath(runId: string): string {
  return join(runDir(runId), "output.md");
}

// ── Initialization ──────────────────────────────────────────────────────────────

/**
 * Ensure the artifacts directory structure exists for a run.
 */
export function ensureRunDir(runId: string): void {
  const dir = runDir(runId);
  if (!existsSync(dir)) {
    mkdirSync(dir, { recursive: true });
  }
  const sdir = stepsDir(runId);
  if (!existsSync(sdir)) {
    mkdirSync(sdir, { recursive: true });
  }
}

// ── Progress Persistence ────────────────────────────────────────────────────────

/**
 * Save the current WorkflowProgress snapshot.
 */
export function saveProgress(runId: string, progress: WorkflowProgress): void {
  ensureRunDir(runId);
  writeFileSync(progressPath(runId), JSON.stringify(progress, null, 2), "utf-8");
}

/**
 * Load a WorkflowProgress snapshot, or null if not found.
 */
export function loadProgress(runId: string): WorkflowProgress | null {
  const pp = progressPath(runId);
  if (!existsSync(pp)) return null;
  try {
    return JSON.parse(readFileSync(pp, "utf-8")) as WorkflowProgress;
  } catch {
    return null;
  }
}

/**
 * Save per-step progress (including output).
 */
export function saveStepProgress(runId: string, step: StepProgress): void {
  ensureRunDir(runId);
  writeFileSync(stepPath(runId, step.stepId), JSON.stringify(step, null, 2), "utf-8");
}

/**
 * Load per-step progress, or null if not found.
 */
export function loadStepProgress(runId: string, stepId: string): StepProgress | null {
  const sp = stepPath(runId, stepId);
  if (!existsSync(sp)) return null;
  try {
    return JSON.parse(readFileSync(sp, "utf-8")) as StepProgress;
  } catch {
    return null;
  }
}

// ── Output Persistence ──────────────────────────────────────────────────────────

/**
 * Save the final assembled workflow output.
 */
export function saveOutput(runId: string, output: string): void {
  ensureRunDir(runId);
  writeFileSync(outputPath(runId), output, "utf-8");
}

/**
 * Load the final assembled output, or null if not found.
 */
export function loadOutput(runId: string): string | null {
  const op = outputPath(runId);
  if (!existsSync(op)) return null;
  try {
    return readFileSync(op, "utf-8");
  } catch {
    return null;
  }
}

// ── Run Listing ─────────────────────────────────────────────────────────────────

/**
 * List all workflow run IDs sorted by most recent first.
 */
export function listRuns(): string[] {
  const wd = workflowsDir();
  if (!existsSync(wd)) return [];
  try {
    return readdirSync(wd, { withFileTypes: true })
      .filter((entry) => entry.isDirectory())
      .map((entry) => entry.name)
      .sort((a, b) => b.localeCompare(a));
  } catch {
    return [];
  }
}

/**
 * List runs with their progress statuses.
 */
export function listRunsWithStatus(): { runId: string; progress: WorkflowProgress | null }[] {
  return listRuns().map((runId) => ({
    runId,
    progress: loadProgress(runId),
  }));
}

// ── Cleanup ─────────────────────────────────────────────────────────────────────

/**
 * Delete all artifacts for a specific run.
 */
export function deleteRun(runId: string): void {
  const dir = runDir(runId);
  if (existsSync(dir)) {
    try {
      rmSync(dir, { recursive: true, force: true });
    } catch {
      // Best effort
    }
  }
}

/**
 * Delete all workflow artifacts (used on full cleanup).
 */
export function deleteAllRuns(): void {
  const wd = workflowsDir();
  if (existsSync(wd)) {
    try {
      rmSync(wd, { recursive: true, force: true });
    } catch {
      // Best effort
    }
  }
}

/**
 * Delete completed/failed/cancelled runs older than maxAgeMs.
 * Returns the number of runs deleted.
 */
export function cleanupOldRuns(maxAgeMs: number = 24 * 60 * 60 * 1000): number {
  const now = Date.now();
  let deleted = 0;
  for (const runId of listRuns()) {
    const progress = loadProgress(runId);
    if (!progress) {
      // No progress file — stale, clean up
      deleteRun(runId);
      deleted++;
      continue;
    }
    if (
      (progress.status === "completed" || progress.status === "failed" || progress.status === "cancelled") &&
      progress.finishedAt !== null &&
      now - progress.finishedAt > maxAgeMs
    ) {
      deleteRun(runId);
      deleted++;
    }
  }
  return deleted;
}