import { AgentRunError } from "../common/errors.js";
import type { CommandRecord, CreateRunInput, JsonRecord, JsonValue, QueueAttemptRef, QueueDispatchResult, QueueTaskRecord, QueueTaskState, RunRecord } from "../common/types.js";
import { asRecord } from "../common/validation.js";
import type { AgentRunStore } from "./store.js";
import { isTerminalQueueTaskState } from "./store.js";
import { createKubernetesRunnerJob, type CreateRunnerJobInput, type RunnerJobDefaults } from "./kubernetes-runner-job.js";

export interface DispatchQueueTaskOptions {
  store: AgentRunStore;
  taskId: string;
  input: JsonRecord;
  defaults: RunnerJobDefaults;
}

export async function dispatchQueueTask(options: DispatchQueueTaskOptions): Promise<QueueDispatchResult> {
  const task = await options.store.getQueueTask(options.taskId);
  assertDispatchable(task);

  const run = await options.store.createRun(buildRunInput(task, options.input));
  const command = await options.store.createCommand(run.id, { type: "turn", payload: task.payload, idempotencyKey: `queue:${task.id}:command` });
  const runnerJob = await createKubernetesRunnerJob({
    store: options.store,
    runId: run.id,
    input: buildRunnerJobInput(task, command.id, options.input),
    defaults: options.defaults,
  });

  const attemptId = stringFrom(runnerJob, "attemptId");
  const runnerJobs = await options.store.listRunnerJobs(run.id, command.id);
  const runnerJobRecord = runnerJobs.find((item) => item.attemptId === attemptId) ?? runnerJobs.at(-1) ?? null;
  const sessionId = run.sessionRef?.sessionId ?? null;
  const sessionPath = sessionId ? `/api/v1/sessions/${encodeURIComponent(sessionId)}` : null;
  const latestAttempt: QueueAttemptRef = {
    attemptId,
    state: "running",
    runId: run.id,
    commandId: command.id,
    runnerJobId: runnerJobRecord?.id ?? null,
    sessionId,
    sessionPath,
  };
  const updatedTask = await options.store.updateQueueTaskAttempt(task.id, { state: "running", latestAttempt, sessionPath });
  await options.store.appendEvent(run.id, "backend_status", { phase: "queue-dispatched", taskId: task.id, queue: task.queue, lane: task.lane, attemptId, runnerJobId: runnerJobRecord?.id ?? null, sessionPath });

  return {
    action: "queue-dispatch",
    mutation: true,
    task: updatedTask,
    run,
    command,
    runnerJob,
    latestAttempt,
    pollCommands: {
      queue: `./scripts/agentrun queue show ${task.id}`,
      run: `./scripts/agentrun runs show ${run.id}`,
      command: `./scripts/agentrun commands show ${command.id} --run-id ${run.id}`,
      events: `./scripts/agentrun runs events ${run.id} --after-seq 0 --limit 100`,
    },
  };
}

export async function refreshQueueTaskFromCore(store: AgentRunStore, taskId: string): Promise<QueueTaskRecord> {
  const task = await store.getQueueTask(taskId);
  if (isTerminalQueueTaskState(task.state)) return task;
  const latestAttempt = task.latestAttempt;
  if (!latestAttempt?.runId || !latestAttempt.commandId) throw new AgentRunError("schema-invalid", `queue task ${taskId} has no Core attempt to refresh`, { httpStatus: 409 });
  const [run, command] = await Promise.all([store.getRun(latestAttempt.runId), store.getCommand(latestAttempt.commandId)]);
  if (command.runId !== run.id) throw new AgentRunError("schema-invalid", `queue task ${taskId} attempt references mismatched run and command`, { httpStatus: 409 });
  const state = queueStateFromCore(run, command);
  const sessionId = run.sessionRef?.sessionId ?? latestAttempt.sessionId ?? null;
  const sessionPath = sessionId ? `/api/v1/sessions/${encodeURIComponent(sessionId)}` : latestAttempt.sessionPath ?? null;
  const nextAttempt: QueueAttemptRef = { ...latestAttempt, state, sessionId, sessionPath };
  return store.updateQueueTaskAttempt(task.id, { state, latestAttempt: nextAttempt, sessionPath });
}

function assertDispatchable(task: QueueTaskRecord): void {
  if (isTerminalQueueTaskState(task.state)) throw new AgentRunError(task.state === "cancelled" ? "cancelled" : "schema-invalid", `queue task ${task.id} is already terminal: ${task.state}`, { httpStatus: 409 });
  if (task.state !== "pending") throw new AgentRunError("schema-invalid", `queue task ${task.id} is not pending: ${task.state}`, { httpStatus: 409 });
  if (!task.workspaceRef) throw new AgentRunError("schema-invalid", "queue dispatch requires workspaceRef", { httpStatus: 400 });
  if (!task.providerId) throw new AgentRunError("schema-invalid", "queue dispatch requires providerId", { httpStatus: 400 });
  if (!task.executionPolicy) throw new AgentRunError("schema-invalid", "queue dispatch requires executionPolicy", { httpStatus: 400 });
}

function queueStateFromCore(run: RunRecord, command: CommandRecord): QueueTaskState {
  if (command.state === "completed") return "completed";
  if (command.state === "failed") return "failed";
  if (command.state === "cancelled") return "cancelled";
  if (run.status === "completed") return "completed";
  if (run.status === "failed") return "failed";
  if (run.status === "blocked") return "blocked";
  if (run.status === "cancelled") return "cancelled";
  return "running";
}

function buildRunInput(task: QueueTaskRecord, input: JsonRecord): CreateRunInput {
  if (!task.workspaceRef || !task.providerId || !task.executionPolicy) throw new AgentRunError("schema-invalid", "queue dispatch task is missing runtime fields", { httpStatus: 400 });
  const traceSink = input.traceSink === undefined ? { kind: "queue", taskId: task.id, queue: task.queue, lane: task.lane } : input.traceSink;
  return {
    tenantId: task.tenantId,
    projectId: task.projectId,
    workspaceRef: task.workspaceRef,
    sessionRef: task.sessionRef,
    resourceBundleRef: task.resourceBundleRef,
    providerId: task.providerId,
    backendProfile: task.backendProfile,
    executionPolicy: task.executionPolicy,
    traceSink: traceSink as JsonValue,
  };
}

function buildRunnerJobInput(task: QueueTaskRecord, commandId: string, input: JsonRecord): CreateRunnerJobInput {
  const jobInput: CreateRunnerJobInput = { commandId, idempotencyKey: optionalString(input.idempotencyKey) ?? `queue:${task.id}:runner-job` };
  const copyString = (inputKey: string, outputKey: keyof CreateRunnerJobInput): void => {
    const value = optionalString(input[inputKey]);
    if (value) jobInput[outputKey] = value as never;
  };
  copyString("managerUrl", "managerUrl");
  copyString("image", "image");
  copyString("namespace", "namespace");
  copyString("attemptId", "attemptId");
  copyString("runnerId", "runnerId");
  copyString("sourceCommit", "sourceCommit");
  copyString("serviceAccountName", "serviceAccountName");
  if (input.transientEnv !== undefined) {
    if (!Array.isArray(input.transientEnv)) throw new AgentRunError("schema-invalid", "transientEnv must be an array", { httpStatus: 400 });
    jobInput.transientEnv = input.transientEnv.map((item, index) => asRecord(item, `transientEnv[${index}]`));
  }
  return jobInput;
}

function stringFrom(record: JsonRecord, key: string): string {
  const value = record[key];
  if (typeof value !== "string" || value.length === 0) throw new AgentRunError("infra-failed", `runner job response missing ${key}`, { httpStatus: 502 });
  return value;
}

function optionalString(value: unknown): string | undefined {
  return typeof value === "string" && value.trim().length > 0 ? value.trim() : undefined;
}