import type { Command } from "commander";
import type { AgentSnapshotPayload } from "@getpaseo/server";
import { connectToDaemon, getDaemonHost } from "../../utils/client.js";
import type { CommandOptions, ListResult, OutputSchema, CommandError } from "../../output/index.js";
import { collectMultiple } from "../../utils/command-options.js";
import { isSameOrDescendantPath } from "../../utils/paths.js";

export function addLsOptions(cmd: Command): Command {
  return cmd
    .description("List agents. By default excludes archived agents.")
    .option("-a, --all", "Include archived agents")
    .option("-g, --global", "Legacy no-op (kept for compatibility)")
    .option(
      "--label <key=value>",
      "Filter by label (can be used multiple times)",
      collectMultiple,
      [],
    )
    .option("--thinking <id>", "Filter by thinking option ID");
}

/** Agent list item for display */
export interface AgentListItem {
  id: string;
  shortId: string;
  name: string;
  provider: string;
  terminal: boolean;
  thinking: string;
  status: string;
  cwd: string;
  created: string;
}

/** Helper to get relative time string */
function relativeTime(date: Date | string): string {
  const now = Date.now();
  const then = new Date(date).getTime();
  const seconds = Math.floor((now - then) / 1000);

  if (seconds < 60) return "just now";
  if (seconds < 3600) return `${Math.floor(seconds / 60)} minutes ago`;
  if (seconds < 86400) return `${Math.floor(seconds / 3600)} hours ago`;
  return `${Math.floor(seconds / 86400)} days ago`;
}

/** Shorten home directory in path */
function shortenPath(path: string): string {
  const home = process.env.HOME;
  if (home && path.startsWith(home)) {
    return "~" + path.slice(home.length);
  }
  return path;
}

function normalizeModelId(modelId: string | null | undefined): string | null {
  if (typeof modelId !== "string") return null;
  const normalized = modelId.trim();
  if (!normalized || normalized.toLowerCase() === "default") return null;
  return normalized;
}

/** Schema for agent ls output */
export const agentLsSchema: OutputSchema<AgentListItem> = {
  idField: "shortId",
  columns: [
    { header: "AGENT ID", field: "shortId", width: 12 },
    { header: "NAME", field: "name", width: 20 },
    { header: "PROVIDER", field: "provider", width: 15 },
    { header: "TERM", field: "terminal", width: 6 },
    { header: "THINKING", field: "thinking", width: 12 },
    {
      header: "STATUS",
      field: "status",
      width: 10,
      color: (value) => {
        if (value === "running") return "green";
        if (value === "idle") return "yellow";
        if (value === "error") return "red";
        return undefined;
      },
    },
    { header: "CWD", field: "cwd", width: 30 },
    { header: "CREATED", field: "created", width: 15 },
  ],
};

/** Transform agent snapshot to AgentListItem */
function toListItem(agent: AgentSnapshotPayload): AgentListItem {
  const model = normalizeModelId(agent.runtimeInfo?.model) ?? normalizeModelId(agent.model);
  return {
    id: agent.id,
    shortId: agent.id.slice(0, 7),
    name: agent.title ?? "-",
    provider: model ? `${agent.provider}/${model}` : agent.provider,
    terminal: agent.terminal === true,
    thinking: agent.effectiveThinkingOptionId ?? "auto",
    status: agent.status,
    cwd: shortenPath(agent.cwd),
    created: relativeTime(agent.createdAt),
  };
}

export type AgentLsResult = ListResult<AgentListItem>;

export interface AgentLsOptions extends CommandOptions {
  /** -a: Include archived agents */
  all?: boolean;
  /** Legacy flag retained for CLI compatibility */
  global?: boolean;
  /** Filter by specific status */
  status?: string;
  /** Filter by specific cwd */
  cwd?: string;
  /** Filter by labels (key=value format) */
  label?: string[];
  /** Filter by thinking option ID */
  thinking?: string;
}

/**
 * Agent ls command semantics:
 * - `paseo agent ls`    → all non-archived agents
 * - `paseo agent ls -a` → include archived agents
 */
export async function runLsCommand(
  options: AgentLsOptions,
  _command: Command,
): Promise<AgentLsResult> {
  const host = getDaemonHost({ host: options.host as string | undefined });

  let client;
  try {
    client = await connectToDaemon({ host: options.host as string | undefined });
  } catch (err) {
    const message = err instanceof Error ? err.message : String(err);
    const error: CommandError = {
      code: "DAEMON_NOT_RUNNING",
      message: `Cannot connect to daemon at ${host}: ${message}`,
      details: "Start the daemon with: paseo daemon start",
    };
    throw error;
  }

  try {
    const normalizedThinkingOptionId = options.thinking?.trim();
    if (options.thinking !== undefined && !normalizedThinkingOptionId) {
      const error: CommandError = {
        code: "INVALID_THINKING_OPTION",
        message: "--thinking cannot be empty",
      };
      throw error;
    }

    // Parse --label filters (key=value).
    const labelFilters: Record<string, string> = {};
    if (options.label) {
      for (const labelStr of options.label) {
        const eqIndex = labelStr.indexOf("=");
        if (eqIndex !== -1) {
          const key = labelStr.slice(0, eqIndex);
          const value = labelStr.slice(eqIndex + 1);
          labelFilters[key] = value;
        }
      }
    }

    const daemonFilter: {
      includeArchived?: boolean;
      labels?: Record<string, string>;
      thinkingOptionId?: string;
    } = {};
    if (options.all) {
      daemonFilter.includeArchived = true;
    }
    if (Object.keys(labelFilters).length > 0) {
      daemonFilter.labels = labelFilters;
    }
    if (normalizedThinkingOptionId) {
      daemonFilter.thinkingOptionId = normalizedThinkingOptionId;
    }

    const fetchPayload = await client.fetchAgents({
      filter: Object.keys(daemonFilter).length > 0 ? daemonFilter : undefined,
    });
    let agents = fetchPayload.entries.map((entry) => entry.agent);

    // By default, exclude archived agents. `-a` includes them.
    if (!options.all) {
      agents = agents.filter((a) => !a.archivedAt);
    }

    // If explicit status filter is provided, apply it.
    if (options.status) {
      agents = agents.filter((a) => a.status === options.status);
    }

    // Optional cwd filter.
    if (options.cwd) {
      agents = agents.filter((a) => isSameOrDescendantPath(options.cwd!, a.cwd));
    }

    // Apply label filtering only when explicitly requested.
    if (Object.keys(labelFilters).length > 0) {
      agents = agents.filter((a) => {
        const agentLabels = a.labels;
        for (const [key, value] of Object.entries(labelFilters)) {
          if (agentLabels[key] !== value) {
            return false;
          }
        }
        return true;
      });
    }

    await client.close();

    // Sort agents: running first, then idle, then others; within each group, most recent first
    const statusOrder = { running: 0, idle: 1 } as Record<string, number>;
    agents.sort((a, b) => {
      // Primary sort: by status
      const aOrder = statusOrder[a.status] ?? 999;
      const bOrder = statusOrder[b.status] ?? 999;
      if (aOrder !== bOrder) return aOrder - bOrder;

      // Secondary sort: by creation time (most recent first)
      const aTime = new Date(a.createdAt).getTime();
      const bTime = new Date(b.createdAt).getTime();
      return bTime - aTime;
    });

    const items = agents.map(toListItem);

    return {
      type: "list",
      data: items,
      schema: agentLsSchema,
    };
  } catch (err) {
    await client.close().catch(() => {});
    const message = err instanceof Error ? err.message : String(err);
    const error: CommandError = {
      code: "LIST_AGENTS_FAILED",
      message: `Failed to list agents: ${message}`,
    };
    throw error;
  }
}