import { readdir, readFile } from "node:fs/promises"
import path from "node:path"

async function safeRead(filePath) {
  try {
    return await readFile(filePath, "utf8")
  } catch {
    return null
  }
}

export const FidelityCompaction = async ({ directory }) => {
  return {
    "experimental.session.compacting": async (_input, output) => {
      const baseFiles = [
        "README.md",
        "ai/context/index.md",
        "ai/context/project.md",
        "ai/context/systems/index.md",
        "ai/context/workstreams/index.md",
        "ai/context/process/communication.md",
        "ai/context/people/manager.md",
        "ai/context/people/index.md",
        "ai/state/current.md",
        "ai/state/work-items.md",
        "ai/context/decisions/rest-vs-graphql.md",
        "ai/context/decisions/discourse-handling.md",
        "knowledge/workspace-model.md",
        "knowledge/communication-rules.md",
      ]

      const sections = []

      for (const relPath of baseFiles) {
        const content = await safeRead(path.join(directory, relPath))
        if (content) {
          sections.push(`### ${relPath}\n${content.trim()}`)
        }
      }

      try {
        const logsDir = path.join(directory, "ai/logs")
        const logs = (await readdir(logsDir))
          .filter((name) => name.endsWith(".md"))
          .sort()
          .slice(-2)

        for (const logName of logs) {
          const content = await safeRead(path.join(logsDir, logName))
          if (content) {
            sections.push(`### ai/logs/${logName}\n${content.trim()}`)
          }
        }
      } catch {
        // No logs available yet.
      }

      if (sections.length > 0) {
        output.context.push(
          [
            "## Fidelity Workspace Persistent Context",
            "Preserve this operational memory across compaction.",
            "If later messages introduced corrections or durable facts, prefer the corrected view over stale summaries.",
            "",
            sections.join("\n\n"),
          ].join("\n"),
        )
      }
    },
  }
}