import fs from "node:fs/promises";
import os from "node:os";
import path from "node:path";
import { fileURLToPath } from "node:url";
import type { AdapterExecutionContext, AdapterExecutionResult } from "@paperclip/adapter-utils";
import type { RunProcessResult } from "@paperclip/adapter-utils/server-utils";
import {
  asString,
  asNumber,
  asBoolean,
  asStringArray,
  parseObject,
  parseJson,
  buildPaperclipEnv,
  redactEnvForLogs,
  ensureAbsoluteDirectory,
  ensureCommandResolvable,
  ensurePathInEnv,
  renderTemplate,
  runChildProcess,
} from "@paperclip/adapter-utils/server-utils";
import { parseClaudeStreamJson, describeClaudeFailure, isClaudeUnknownSessionError } from "./parse.js";

const PAPERCLIP_SKILLS_DIR = path.resolve(
  path.dirname(fileURLToPath(import.meta.url)),
  "../../../../../skills",
);

/**
 * Create a tmpdir with `.claude/skills/` containing symlinks to skills from
 * the repo's `skills/` directory, so `--add-dir` makes Claude Code discover
 * them as proper registered skills.
 */
async function buildSkillsDir(): Promise<string> {
  const tmp = await fs.mkdtemp(path.join(os.tmpdir(), "paperclip-skills-"));
  const target = path.join(tmp, ".claude", "skills");
  await fs.mkdir(target, { recursive: true });
  const entries = await fs.readdir(PAPERCLIP_SKILLS_DIR, { withFileTypes: true });
  for (const entry of entries) {
    if (entry.isDirectory()) {
      await fs.symlink(
        path.join(PAPERCLIP_SKILLS_DIR, entry.name),
        path.join(target, entry.name),
      );
    }
  }
  return tmp;
}

export async function execute(ctx: AdapterExecutionContext): Promise<AdapterExecutionResult> {
  const { runId, agent, runtime, config, context, onLog, onMeta, authToken } = ctx;

  const promptTemplate = asString(
    config.promptTemplate,
    "You are agent {{agent.id}} ({{agent.name}}). Continue your Paperclip work.",
  );
  const bootstrapTemplate = asString(config.bootstrapPromptTemplate, promptTemplate);
  const command = asString(config.command, "claude");
  const model = asString(config.model, "");
  const maxTurns = asNumber(config.maxTurnsPerRun, 0);
  const dangerouslySkipPermissions = asBoolean(config.dangerouslySkipPermissions, false);

  const cwd = asString(config.cwd, process.cwd());
  await ensureAbsoluteDirectory(cwd);
  const envConfig = parseObject(config.env);
  const hasExplicitApiKey =
    typeof envConfig.PAPERCLIP_API_KEY === "string" && envConfig.PAPERCLIP_API_KEY.trim().length > 0;
  const env: Record<string, string> = { ...buildPaperclipEnv(agent) };
  env.PAPERCLIP_RUN_ID = runId;
  const wakeTaskId =
    (typeof context.taskId === "string" && context.taskId.trim().length > 0 && context.taskId.trim()) ||
    (typeof context.issueId === "string" && context.issueId.trim().length > 0 && context.issueId.trim()) ||
    null;
  const wakeReason =
    typeof context.wakeReason === "string" && context.wakeReason.trim().length > 0
      ? context.wakeReason.trim()
      : null;
  const approvalId =
    typeof context.approvalId === "string" && context.approvalId.trim().length > 0
      ? context.approvalId.trim()
      : null;
  const approvalStatus =
    typeof context.approvalStatus === "string" && context.approvalStatus.trim().length > 0
      ? context.approvalStatus.trim()
      : null;
  const linkedIssueIds = Array.isArray(context.issueIds)
    ? context.issueIds.filter((value): value is string => typeof value === "string" && value.trim().length > 0)
    : [];
  if (wakeTaskId) {
    env.PAPERCLIP_TASK_ID = wakeTaskId;
  }
  if (wakeReason) {
    env.PAPERCLIP_WAKE_REASON = wakeReason;
  }
  if (approvalId) {
    env.PAPERCLIP_APPROVAL_ID = approvalId;
  }
  if (approvalStatus) {
    env.PAPERCLIP_APPROVAL_STATUS = approvalStatus;
  }
  if (linkedIssueIds.length > 0) {
    env.PAPERCLIP_LINKED_ISSUE_IDS = linkedIssueIds.join(",");
  }
  for (const [k, v] of Object.entries(envConfig)) {
    if (typeof v === "string") env[k] = v;
  }
  if (!hasExplicitApiKey && authToken) {
    env.PAPERCLIP_API_KEY = authToken;
  }
  const runtimeEnv = ensurePathInEnv({ ...process.env, ...env });
  await ensureCommandResolvable(command, cwd, runtimeEnv);

  const timeoutSec = asNumber(config.timeoutSec, 1800);
  const graceSec = asNumber(config.graceSec, 20);
  const extraArgs = (() => {
    const fromExtraArgs = asStringArray(config.extraArgs);
    if (fromExtraArgs.length > 0) return fromExtraArgs;
    return asStringArray(config.args);
  })();
  const skillsDir = await buildSkillsDir();

  const runtimeSessionParams = parseObject(runtime.sessionParams);
  const runtimeSessionId = asString(runtimeSessionParams.sessionId, runtime.sessionId ?? "");
  const runtimeSessionCwd = asString(runtimeSessionParams.cwd, "");
  const canResumeSession =
    runtimeSessionId.length > 0 &&
    (runtimeSessionCwd.length === 0 || path.resolve(runtimeSessionCwd) === path.resolve(cwd));
  const sessionId = canResumeSession ? runtimeSessionId : null;
  if (runtimeSessionId && !canResumeSession) {
    await onLog(
      "stderr",
      `[paperclip] Claude session "${runtimeSessionId}" was saved for cwd "${runtimeSessionCwd}" and will not be resumed in "${cwd}".\n`,
    );
  }
  const template = sessionId ? promptTemplate : bootstrapTemplate;
  const prompt = renderTemplate(template, {
    agentId: agent.id,
    companyId: agent.companyId,
    runId,
    company: { id: agent.companyId },
    agent,
    run: { id: runId, source: "on_demand" },
    context,
  });

  const buildClaudeArgs = (resumeSessionId: string | null) => {
    const args = ["--print", "-", "--output-format", "stream-json", "--verbose"];
    if (resumeSessionId) args.push("--resume", resumeSessionId);
    if (dangerouslySkipPermissions) args.push("--dangerously-skip-permissions");
    if (model) args.push("--model", model);
    if (maxTurns > 0) args.push("--max-turns", String(maxTurns));
    args.push("--add-dir", skillsDir);
    if (extraArgs.length > 0) args.push(...extraArgs);
    return args;
  };

  const parseFallbackErrorMessage = (proc: RunProcessResult) => {
    const stderrLine =
      proc.stderr
        .split(/\r?\n/)
        .map((line) => line.trim())
        .find(Boolean) ?? "";

    if ((proc.exitCode ?? 0) === 0) {
      return "Failed to parse claude JSON output";
    }

    return stderrLine
      ? `Claude exited with code ${proc.exitCode ?? -1}: ${stderrLine}`
      : `Claude exited with code ${proc.exitCode ?? -1}`;
  };

  const runAttempt = async (resumeSessionId: string | null) => {
    const args = buildClaudeArgs(resumeSessionId);
    if (onMeta) {
      await onMeta({
        adapterType: "claude_local",
        command,
        cwd,
        commandArgs: args,
        env: redactEnvForLogs(env),
        prompt,
        context,
      });
    }

    const proc = await runChildProcess(runId, command, args, {
      cwd,
      env,
      stdin: prompt,
      timeoutSec,
      graceSec,
      onLog,
    });

    const parsedStream = parseClaudeStreamJson(proc.stdout);
    const parsed = parsedStream.resultJson ?? parseJson(proc.stdout);
    return { proc, parsedStream, parsed };
  };

  const toAdapterResult = (
    attempt: {
      proc: RunProcessResult;
      parsedStream: ReturnType<typeof parseClaudeStreamJson>;
      parsed: Record<string, unknown> | null;
    },
    opts: { fallbackSessionId: string | null; clearSessionOnMissingSession?: boolean },
  ): AdapterExecutionResult => {
    const { proc, parsedStream, parsed } = attempt;
    if (proc.timedOut) {
      return {
        exitCode: proc.exitCode,
        signal: proc.signal,
        timedOut: true,
        errorMessage: `Timed out after ${timeoutSec}s`,
        clearSession: Boolean(opts.clearSessionOnMissingSession),
      };
    }

    if (!parsed) {
      return {
        exitCode: proc.exitCode,
        signal: proc.signal,
        timedOut: false,
        errorMessage: parseFallbackErrorMessage(proc),
        resultJson: {
          stdout: proc.stdout,
          stderr: proc.stderr,
        },
        clearSession: Boolean(opts.clearSessionOnMissingSession),
      };
    }

    const usage =
      parsedStream.usage ??
      (() => {
        const usageObj = parseObject(parsed.usage);
        return {
          inputTokens: asNumber(usageObj.input_tokens, 0),
          cachedInputTokens: asNumber(usageObj.cache_read_input_tokens, 0),
          outputTokens: asNumber(usageObj.output_tokens, 0),
        };
      })();

    const resolvedSessionId =
      parsedStream.sessionId ??
      (asString(parsed.session_id, opts.fallbackSessionId ?? "") || opts.fallbackSessionId);
    const resolvedSessionParams = resolvedSessionId
      ? ({ sessionId: resolvedSessionId, cwd } as Record<string, unknown>)
      : null;

    return {
      exitCode: proc.exitCode,
      signal: proc.signal,
      timedOut: false,
      errorMessage:
        (proc.exitCode ?? 0) === 0
          ? null
          : describeClaudeFailure(parsed) ?? `Claude exited with code ${proc.exitCode ?? -1}`,
      usage,
      sessionId: resolvedSessionId,
      sessionParams: resolvedSessionParams,
      sessionDisplayId: resolvedSessionId,
      provider: "anthropic",
      model: parsedStream.model || asString(parsed.model, model),
      costUsd: parsedStream.costUsd ?? asNumber(parsed.total_cost_usd, 0),
      resultJson: parsed,
      summary: parsedStream.summary || asString(parsed.result, ""),
      clearSession: Boolean(opts.clearSessionOnMissingSession && !resolvedSessionId),
    };
  };

  try {
    const initial = await runAttempt(sessionId ?? null);
    if (
      sessionId &&
      !initial.proc.timedOut &&
      (initial.proc.exitCode ?? 0) !== 0 &&
      initial.parsed &&
      isClaudeUnknownSessionError(initial.parsed)
    ) {
      await onLog(
        "stderr",
        `[paperclip] Claude resume session "${sessionId}" is unavailable; retrying with a fresh session.\n`,
      );
      const retry = await runAttempt(null);
      return toAdapterResult(retry, { fallbackSessionId: null, clearSessionOnMissingSession: true });
    }

    return toAdapterResult(initial, { fallbackSessionId: runtimeSessionId || runtime.sessionId });
  } finally {
    fs.rm(skillsDir, { recursive: true, force: true }).catch(() => {});
  }
}