import type { Client } from "ssh2";
import type { PluginHostUpdateInput } from "@termix/plugin-sdk/backend";
import { execCommand } from "@termix/plugin-sdk/host-commands";
import { getTool } from "./catalog.js";
import type { ToolDeps } from "./types.js";
import { requireService, SERVICE } from "../services.js";

/** Approved commands get a bounded window rather than hanging the request. */
const COMMAND_TIMEOUT_MS = 60_000;

/**
 * Applies an approved proposal.
 *
 * The stored payload is treated as untrusted input even though the server wrote
 * it: the proposal could have sat in the table across a release, and defending
 * the apply path rather than the create path means one place to get right.
 * Everything goes through the same core APIs and plugin services a human
 * action uses, and runs as the approving user: the apply request's actor.
 */

export interface ApplyResult {
  ok: boolean;
  summary: string;
}

function requireNumber(value: unknown, field: string): number {
  const parsed = Number(value);
  if (!Number.isInteger(parsed) || parsed <= 0) {
    throw new Error(`${field} must be a positive integer`);
  }
  return parsed;
}

function requireString(value: unknown, field: string): string {
  if (typeof value !== "string" || !value.trim()) {
    throw new Error(`${field} is required`);
  }
  return value.trim();
}

function optionalString(value: unknown): string | null {
  if (typeof value !== "string") return null;
  const trimmed = value.trim();
  return trimmed ? trimmed : null;
}

/** Tags as ssh_data stores them, comma-separated. */
function joinTags(value: unknown): string {
  if (!Array.isArray(value)) return "";
  return value
    .filter((tag): tag is string => typeof tag === "string")
    .map((tag) => tag.trim().replace(/,/g, ""))
    .filter(Boolean)
    .join(",");
}

async function requirePermission(
  deps: ToolDeps,
  permission: string,
): Promise<void> {
  if (!(await deps.rbac.has(permission))) {
    throw new Error("You do not have permission to do this");
  }
}

export async function applyProposal(
  kind: string,
  payload: Record<string, unknown>,
  deps: ToolDeps,
): Promise<ApplyResult> {
  // A payload whose tool no longer exists is refused rather than guessed at.
  if (!getTool(kind)) {
    throw new Error(`Unknown proposal kind: ${kind}`);
  }

  switch (kind) {
    case "propose_create_host": {
      await requirePermission(deps, "hosts.create");
      const created = await deps.hosts.create({
        name: requireString(payload.name, "name"),
        ip: requireString(payload.ip, "ip"),
        port: Number(payload.port) || 22,
        username: optionalString(payload.username) ?? "",
        // Credentials are attached by the user after approving.
        authType: "password",
        folder: optionalString(payload.folder),
        tags: joinTags(payload.tags),
      });
      return { ok: true, summary: `Created host ${created.name ?? ""}`.trim() };
    }

    case "propose_update_host": {
      await requirePermission(deps, "hosts.edit");
      const hostId = requireNumber(payload.hostId, "hostId");
      const changes = (payload.changes ?? {}) as Record<string, unknown>;

      const updates: PluginHostUpdateInput = {};
      if (changes.name !== undefined)
        updates.name = requireString(changes.name, "name");
      if (changes.ip !== undefined)
        updates.ip = requireString(changes.ip, "ip");
      if (changes.port !== undefined) updates.port = Number(changes.port);
      if (changes.username !== undefined)
        updates.username = optionalString(changes.username) ?? "";
      if (changes.folder !== undefined)
        updates.folder = optionalString(changes.folder);
      if (changes.tags !== undefined) updates.tags = joinTags(changes.tags);

      if (!Object.keys(updates).length) {
        return { ok: false, summary: "Nothing to change" };
      }

      // update() refuses a host the approving user does not own.
      const updated = await deps.hosts.update(hostId, updates);
      if (!updated) throw new Error("Host not found");
      return { ok: true, summary: `Updated host ${hostId}` };
    }

    case "propose_delete_host": {
      const hostId = requireNumber(payload.hostId, "hostId");
      // delete() checks hosts.delete and ownership itself.
      const deleted = await deps.hosts.delete(hostId);
      if (!deleted) throw new Error("Host not found");
      return { ok: true, summary: `Deleted host ${hostId}` };
    }

    case "propose_create_snippet": {
      const created = await requireService(
        deps.services,
        SERVICE.snippets,
      ).create({
        name: requireString(payload.name, "name"),
        content: requireString(payload.content, "content"),
        description: optionalString(payload.description),
        folder: optionalString(payload.folder),
      });
      return {
        ok: true,
        summary: `Created snippet ${created.name}`.trim(),
      };
    }

    case "propose_update_snippet": {
      const snippetId = requireNumber(payload.snippetId, "snippetId");
      const changes = (payload.changes ?? {}) as Record<string, unknown>;

      const snippets = requireService(deps.services, SERVICE.snippets);
      const existing = await snippets.get(snippetId);
      if (!existing) throw new Error("Snippet not found");

      const updates: Record<string, unknown> = {};
      if (changes.name !== undefined)
        updates.name = requireString(changes.name, "name");
      if (changes.content !== undefined)
        updates.content = requireString(changes.content, "content");
      if (changes.description !== undefined)
        updates.description = optionalString(changes.description);
      if (changes.folder !== undefined)
        updates.folder = optionalString(changes.folder);

      if (!Object.keys(updates).length) {
        return { ok: false, summary: "Nothing to change" };
      }

      await snippets.update(snippetId, updates);
      return { ok: true, summary: `Updated snippet ${snippetId}` };
    }

    case "propose_delete_snippet": {
      const snippetId = requireNumber(payload.snippetId, "snippetId");
      const deleted = await requireService(
        deps.services,
        SERVICE.snippets,
      ).remove(snippetId);
      if (!deleted) throw new Error("Snippet not found");
      return { ok: true, summary: `Deleted snippet ${snippetId}` };
    }

    case "propose_create_fleet": {
      const fleets = requireService(deps.services, SERVICE.fleets);
      const fleet = await fleets.create({
        name: requireString(payload.name, "name"),
        description: optionalString(payload.description),
      });

      const hostIds = Array.isArray(payload.hostIds) ? payload.hostIds : [];
      let added = 0;
      for (const raw of hostIds) {
        const hostId = Number(raw);
        if (!Number.isInteger(hostId) || hostId <= 0) continue;
        // Only hosts the approving user owns can join their fleet.
        const access = await deps.hosts.checkAccess(hostId, "view");
        if (!access.isOwner) continue;
        await fleets.addMember(fleet.id, hostId);
        added += 1;
      }

      return {
        ok: true,
        summary: `Created fleet ${fleet.name} with ${added} host${added === 1 ? "" : "s"}`,
      };
    }

    case "propose_create_automation": {
      // The automations plugin runs the same validator its own route does,
      // so an LLM-authored definition is held to exactly the human standard.
      const created = await requireService(
        deps.services,
        SERVICE.automations,
      ).create({
        name: requireString(payload.name, "name"),
        description: optionalString(payload.description),
        definition: payload.definition,
        // Starts disabled: an automation the user has not watched run once
        // should not begin firing against their servers on approval.
        enabled: false,
      });

      return {
        ok: true,
        summary: `Created automation ${created.name} (disabled until you enable it)`,
      };
    }

    case "propose_run_command": {
      const hostId = requireNumber(payload.hostId, "hostId");
      const command = requireString(payload.command, "command");

      // ctx.ssh resolves the host for the approving user, with the same
      // connect-level access check, owner-key decryption and jump chain a
      // terminal gets.
      const result = await runCommandOnHost(deps, hostId, command);
      if (result.error) {
        throw new Error(result.error);
      }
      return {
        ok: true,
        summary: result.output?.slice(0, 2000) ?? "(no output)",
      };
    }

    default:
      throw new Error(`Proposal kind ${kind} cannot be applied automatically`);
  }
}

/**
 * Runs one approved command over this plugin's SSH pool, mirroring how an
 * automation run_command step executes.
 */
export async function runCommandOnHost(
  deps: ToolDeps,
  hostId: number,
  command: string,
): Promise<{ output?: string; error?: string }> {
  try {
    const result = await deps.ssh.withConnection<
      Awaited<ReturnType<typeof execCommand>>,
      Client
    >(hostId, { pool: "ai", purpose: "fleet" }, (client) =>
      execCommand(client, command, COMMAND_TIMEOUT_MS),
    );

    const output = [result.stdout, result.stderr].filter(Boolean).join("\n");
    if (result.code === 0 || result.code === null) {
      return { output: output || "(no output)" };
    }
    return { error: `Exited with code ${result.code}: ${output}`.trim() };
  } catch (error) {
    return {
      error: error instanceof Error ? error.message : String(error),
    };
  }
}

/**
 * Kinds the route handles itself rather than through applyProposal.
 * Empty: everything the assistant can propose can now be applied.
 */
export const ROUTE_APPLIED_KINDS = new Set<string>();