import { existsSync } from "node:fs";
import { parseArgs } from "node:util";
import { ConfigError, DEFAULT_CONFIG_PATH, loadConfig, parseNodeId, type Config } from "./config.js";
import { commissionedNodeIds, resolveSingleNode, resolveTargetNodes, startController } from "./controller.js";
import { commissionDevice } from "./commissioning.js";
import { connectDevice } from "./device.js";
import { findLikelyStrays, formatFabricTable, readFabricTable } from "./fabrics.js";
import { formatInspection, inspectNode } from "./inspection.js";
import { toJsonString } from "./json.js";
import { Log, describeError, setLogLevel } from "./logging.js";
import { currentMatterUtcMicroseconds, isHostClockSynchronized } from "./sync.js";
import { formatSyncResult, syncNode, type SyncNodeResult } from "./timesync.js";
import { nodeState, readServiceState, removeNodeState, serviceStatePath, updateNodeState } from "./state.js";
import { formatUtcOffset, nextOffsetTransition, utcOffsetSeconds } from "./timezone.js";

const log = new Log("cli");

const USAGE = `Usage: mattertimesync [--config <path>] <command> [options]

Read-only commands (never modify a device):
  status [--json]                      Show controller and per-device state (contacts no device)
  nodes [--json]                       List commissioned devices from local cached state (contacts no device)
  inspect [--node <id>] [--json]       Connect to a device and dump its live endpoints, clusters,
                                       time-sync capabilities, and fabric table

Commands with side effects:
  commission <pairing-code>            Join a device as an additional Matter admin
                                       (writes the device's fabric table and local storage)
  sync [--node <id>] [--json]          Set each device's clock: UTC time, time zone, DST offsets
  decommission [--node <id>]           Drop this controller's fabric from each device, or just
                                       one with --node (primary ecosystems are untouched)

The controller fabric is the device registry: every commissioned node is kept
in sync. --node may be omitted while only one device is commissioned.
Run "sync" periodically (e.g. from a systemd timer) to keep clocks correct.

Logs go to stderr; command output (including --json) goes to stdout.

Options:
  --config <path>   Configuration file (default: ${DEFAULT_CONFIG_PATH})
  --json            Machine-readable output (64-bit values as decimal strings)
  --help            Show this help
`;

async function main(): Promise<number> {
  const { values, positionals } = parseArgs({
    options: {
      config: { type: "string" },
      json: { type: "boolean", default: false },
      node: { type: "string" },
      help: { type: "boolean", default: false },
    },
    allowPositionals: true,
  });

  if (values.help || positionals.length === 0) {
    process.stdout.write(USAGE);
    return values.help ? 0 : 2;
  }

  const command = positionals[0]!;
  const configPath = values.config ?? DEFAULT_CONFIG_PATH;

  let config: Config;
  let requestedNode: bigint | undefined;
  try {
    config = loadConfig(configPath);
    requestedNode = values.node === undefined ? undefined : parseNodeId(values.node);
  } catch (cause) {
    if (cause instanceof ConfigError) {
      process.stderr.write(`Configuration error: ${cause.message}\n`);
      return 1;
    }
    throw cause;
  }
  setLogLevel(config.logLevel);

  switch (command) {
    case "commission":
      return await runCommission(config, positionals[1]);
    case "nodes":
      return await runNodes(config, values.json ?? false);
    case "inspect":
      return await runInspect(config, requestedNode, values.json ?? false);
    case "sync":
      return await runSync(config, requestedNode, values.json ?? false);
    case "status":
      return await runStatus(config, values.json ?? false);
    case "decommission":
      return await runDecommission(config, requestedNode);
    default:
      process.stderr.write(`Unknown command "${command}"\n\n${USAGE}`);
      return 2;
  }
}

async function runCommission(config: Config, codeArgument: string | undefined): Promise<number> {
  const pairingCode = codeArgument?.trim();
  if (pairingCode === undefined || pairingCode.length === 0) {
    process.stderr.write(
      "Usage: commission <pairing-code> (the code from the primary ecosystem's pairing mode).\n" +
        "The code is used once and never logged or stored.\n",
    );
    return 2;
  }
  const controller = await startController(config);
  try {
    const result = await commissionDevice(controller, config, pairingCode);

    const node = await connectDevice(controller, result.nodeId);
    updateNodeState(serviceStatePath(config.storagePath), result.nodeId, {
      lastSuccessfulConnection: new Date().toISOString(),
    });
    const report = await inspectNode(node);
    process.stdout.write(formatInspection(report) + "\n\n");

    process.stdout.write(
      [
        "Commissioning summary",
        `  Node ID:        ${result.nodeId}`,
        `  Fabric ID:      ${controller.fabric.fabricId}`,
        `  Total devices:  ${commissionedNodeIds(controller).length}`,
        `  Time Sync:      ${
          report.timeSynchronization
            ? `endpoint ${report.timeSynchronization.endpointId}`
            : "cluster not found"
        }`,
        "",
        "The device remains paired with its primary ecosystem; this controller",
        'was added as an additional Matter administrator. Run "sync" to',
        "synchronize its clock now.",
        "",
      ].join("\n"),
    );
    return 0;
  } finally {
    await controller.close();
  }
}

async function runNodes(config: Config, json: boolean): Promise<number> {
  const controller = await startController(config);
  try {
    const details = controller.getCommissionedNodesDetails();
    const state = readServiceState(serviceStatePath(config.storagePath));

    if (json) {
      const entries = details.map(detail => {
        const nodeId = BigInt(detail.nodeId);
        const info = detail.deviceData.basicInformation ?? {};
        return {
          nodeId,
          vendorName: info["vendorName"] ?? null,
          productName: info["productName"] ?? null,
          ...nodeState(state, nodeId),
        };
      });
      process.stdout.write(toJsonString(entries) + "\n");
      return 0;
    }

    if (details.length === 0) {
      process.stdout.write('No devices commissioned. Run "commission" to add one.\n');
      return 0;
    }

    process.stdout.write(`${details.length} commissioned device${details.length === 1 ? "" : "s"}:\n`);
    for (const detail of details) {
      const nodeId = BigInt(detail.nodeId);
      const info = detail.deviceData.basicInformation ?? {};
      const name = [info["vendorName"], info["productName"]].filter(Boolean).join(" ");
      const perNode = nodeState(state, nodeId);
      process.stdout.write(
        [
          `  node ${nodeId}: ${name || "(no cached device info)"}`,
          `    last connection: ${perNode.lastSuccessfulConnection ?? "never"}`,
          `    last sync:       ${perNode.lastSuccessfulSync ?? "never"}`,
          ...(perNode.lastError !== null ? [`    last error:      ${perNode.lastError}`] : []),
        ].join("\n") + "\n",
      );
    }
    return 0;
  } finally {
    await controller.close();
  }
}

async function runInspect(config: Config, requestedNode: bigint | undefined, json: boolean): Promise<number> {
  const controller = await startController(config);
  try {
    const nodeId = resolveSingleNode(controller, requestedNode);
    const node = await connectDevice(controller, nodeId);
    updateNodeState(serviceStatePath(config.storagePath), nodeId, {
      lastSuccessfulConnection: new Date().toISOString(),
    });
    const report = await inspectNode(node);
    const fabricTable = await readFabricTable(controller, node);
    if (json) {
      process.stdout.write(
        toJsonString({
          ...report,
          fabricTable: {
            ...fabricTable,
            likelyStaleIndexes: findLikelyStrays(fabricTable).map(entry => entry.fabricIndex),
          },
        }) + "\n",
      );
    } else {
      process.stdout.write(formatInspection(report) + "\n\n" + formatFabricTable(nodeId, fabricTable) + "\n");
    }
    return 0;
  } finally {
    await controller.close();
  }
}

async function runSync(config: Config, requestedNode: bigint | undefined, json: boolean): Promise<number> {
  // Fail safe: never push time from a clock that is not NTP-disciplined.
  const ntpSynchronized = await isHostClockSynchronized();
  if (!ntpSynchronized) {
    log.warn("Host clock is not NTP-synchronized; refusing to set device time. Will retry next run.");
    if (json) process.stdout.write(toJsonString({ hostNtpSynchronized: false, nodes: [] }) + "\n");
    return 1;
  }

  const controller = await startController(config);
  const statePath = serviceStatePath(config.storagePath);
  const results: SyncNodeResult[] = [];
  try {
    for (const nodeId of resolveTargetNodes(controller, requestedNode)) {
      updateNodeState(statePath, nodeId, { lastAttemptedSync: new Date().toISOString() });
      let result: SyncNodeResult;
      try {
        const node = await connectDevice(controller, nodeId);
        updateNodeState(statePath, nodeId, { lastSuccessfulConnection: new Date().toISOString() });
        result = await syncNode(node, config.timezone);
      } catch (cause) {
        result = {
          nodeId: nodeId.toString(),
          success: false,
          skipped: false,
          error: describeError(cause),
          clockBefore: null,
          utcTimeWritten: null,
          utcTimeWrittenUnixMicroseconds: null,
          timeZoneWritten: null,
          dstOffsetsWritten: null,
          verification: null,
        };
      }
      results.push(result);
      if (result.success) {
        updateNodeState(statePath, nodeId, {
          lastSuccessfulSync: new Date().toISOString(),
          lastError: null,
        });
      } else {
        updateNodeState(statePath, nodeId, { lastError: result.error });
        log.error(`Node ${nodeId}: sync failed`, result.error);
      }
    }
  } finally {
    await controller.close();
  }

  if (json) {
    process.stdout.write(toJsonString({ hostNtpSynchronized: true, nodes: results }) + "\n");
  } else {
    process.stdout.write(results.map(result => formatSyncResult(result)).join("\n") + "\n");
  }
  // Devices without the cluster are skipped with a warning, not treated as
  // failures; a permanently incompatible device must not fail every timer run.
  return results.some(result => !result.success && !result.skipped) ? 1 : 0;
}

async function runStatus(config: Config, json: boolean): Promise<number> {
  const statePath = serviceStatePath(config.storagePath);
  const state = readServiceState(statePath);
  const storageExists = existsSync(config.storagePath);
  const ntpSynchronized = await isHostClockSynchronized();
  const offsetSeconds = utcOffsetSeconds(config.timezone);
  const transition = nextOffsetTransition(config.timezone);

  if (json) {
    process.stdout.write(
      toJsonString({
        timezone: config.timezone,
        storagePath: config.storagePath,
        storageInitialized: storageExists,
        hostNtpSynchronized: ntpSynchronized,
        currentUtcOffsetSeconds: offsetSeconds,
        currentUtcOffset: formatUtcOffset(offsetSeconds),
        nextDstTransition:
          transition === null
            ? null
            : {
                at: transition.at.toISOString(),
                offsetBeforeSeconds: transition.offsetBeforeSeconds,
                offsetAfterSeconds: transition.offsetAfterSeconds,
              },
        matterTimeNowMicroseconds: currentMatterUtcMicroseconds(),
        nodes: state.nodes,
      }) + "\n",
    );
    return 0;
  }

  const nodeIds = Object.keys(state.nodes);
  const lines = [
    `Configuration:        loaded (${config.timezone})`,
    `Controller storage:   ${storageExists ? `present at ${config.storagePath}` : "NOT INITIALIZED"}`,
    `Commissioned nodes:   ${nodeIds.length > 0 ? nodeIds.join(", ") : "none recorded"}`,
    `Host NTP synced:      ${ntpSynchronized ? "yes" : "no (or not determinable on this host)"}`,
    `Current UTC offset:   ${formatUtcOffset(offsetSeconds)}`,
    `Next DST transition:  ${
      transition
        ? `${transition.at.toISOString()} (${formatUtcOffset(transition.offsetBeforeSeconds)} -> ${formatUtcOffset(
            transition.offsetAfterSeconds,
          )})`
        : "none within 400 days"
    }`,
    `Matter time now:      ${currentMatterUtcMicroseconds()} us since 2000-01-01T00:00:00Z`,
  ];
  for (const [nodeId, perNode] of Object.entries(state.nodes)) {
    lines.push(`Node ${nodeId}:`);
    lines.push(`  Last connection:      ${perNode.lastSuccessfulConnection ?? "never"}`);
    lines.push(`  Last successful sync: ${perNode.lastSuccessfulSync ?? "never"}`);
    lines.push(`  Last attempted sync:  ${perNode.lastAttemptedSync ?? "never"}`);
    lines.push(`  Most recent error:    ${perNode.lastError ?? "none"}`);
  }
  process.stdout.write(lines.join("\n") + "\n");
  return 0;
}

async function runDecommission(config: Config, requestedNode: bigint | undefined): Promise<number> {
  const controller = await startController(config);
  const statePath = serviceStatePath(config.storagePath);
  const failed: bigint[] = [];
  try {
    // Like sync, no --node means every commissioned device.
    for (const nodeId of resolveTargetNodes(controller, requestedNode)) {
      try {
        const node = await connectDevice(controller, nodeId);
        log.info(`Decommissioning: removing this controller's fabric from node ${nodeId}`);
        await node.decommission();
        removeNodeState(statePath, nodeId);
        process.stdout.write(
          `Device ${nodeId} removed this controller's fabric; its primary ecosystem is untouched.\n`,
        );
      } catch (cause) {
        failed.push(nodeId);
        log.error(`Node ${nodeId}: decommission failed`, cause);
        process.stdout.write(`Device ${nodeId} could NOT be decommissioned: ${describeError(cause)}\n`);
      }
    }

    const remaining = commissionedNodeIds(controller);
    process.stdout.write(
      (remaining.length > 0
        ? `${remaining.length} device${remaining.length === 1 ? "" : "s"} remain commissioned: ${remaining.join(", ")}.`
        : `No devices remain commissioned. Local controller identity remains in ` +
          `${config.storagePath}; deleting that directory is now safe, or keep it to reuse ` +
          `the same identity for future commissioning.`) + "\n",
    );
    return failed.length > 0 ? 1 : 0;
  } finally {
    await controller.close();
  }
}

main()
  .then(code => {
    process.exitCode = code;
  })
  .catch(cause => {
    log.error("Fatal error", cause);
    if (!(cause instanceof Error)) {
      process.stderr.write(describeError(cause) + "\n");
    }
    process.exitCode = 1;
  });