/**
 * Marketing-Funnel Phase 3 (Phase 05 #80) — sequence trigger handler.
 *
 * Subscribed to BullMQ queue `outbox.marketing` (and a fan-out for
 * `tenant.*` lifecycle events). For every received outbox-event the
 * handler:
 *   1. Normalises the event-type (strip `marketing.` prefix so
 *      `marketing.lead.captured` matches sequences with trigger
 *      `lead.captured`).
 *   2. Looks up all enabled EmailSequences with matching `triggerEvent`.
 *   3. Builds a `SequenceTriggerContext` from the outbox payload
 *      (lead-id, tenant-id, recipient email + name, payload bag for
 *      condition evaluation).
 *   4. Invokes {@link startSequenceRun} once per sequence. Idempotency
 *      is provided by `(sequenceId, triggerEventId)` unique constraint
 *      on EmailSequenceRun — duplicate deliveries are no-ops.
 *
 * Storage + queue + sequence-loader surfaces are injected so the
 * handler is fully unit-testable. Production wiring lives in
 * `email-sequence-trigger-bootstrap.ts`.
 */

import {
  startSequenceRun,
  type SequenceDefinition,
  type SequenceEngineQueue,
  type SequenceEngineStore,
  type SequenceTriggerContext,
} from "@toolctrl/email-sequences";

export const EMAIL_SEQUENCE_TRIGGER_QUEUE = "outbox.marketing" as const;

/** Set of outbox event-types this handler will react to. */
export const SEQUENCE_TRIGGER_EVENT_TYPES: ReadonlyArray<string> = [
  "marketing.lead.captured",
  "marketing.lead.qualified",
  "marketing.lead.convertedtotrial",
  "marketing.lead.convertedtocustomer",
  "marketing.lead.stale_60d",
  "lead.captured",
  "lead.qualified",
  "lead.converted_to_trial",
  "lead.converted_to_customer",
  "lead.stale_60d",
  "tenant.signup",
  "tenant.trial_expiring",
  "tenant.cancelled",
];

export interface SequenceTriggerJobData {
  /** Outbox row id — used for idempotency in startSequenceRun. */
  readonly outboxEventId?: string;
  readonly tenantId?: string | null;
  readonly eventType: string;
  readonly payload: Readonly<Record<string, unknown>>;
}

export class SequenceTriggerJobError extends Error {
  override readonly name = "SequenceTriggerJobError";
  readonly code: "INVALID_PAYLOAD" | "UNKNOWN_EVENT_TYPE";
  constructor(message: string, code: SequenceTriggerJobError["code"]) {
    super(message);
    this.code = code;
  }
}

export interface SequenceTriggerLogger {
  info?: (record: Record<string, unknown>, message?: string) => void;
  warn?: (record: Record<string, unknown>, message?: string) => void;
  error: (record: Record<string, unknown>, message?: string) => void;
}

/**
 * Read-side surface needed to find sequences matching an event. The
 * production implementation queries Prisma; tests provide an in-memory
 * fake.
 */
export interface SequenceTriggerLoader {
  listEnabledForEvent(normalisedEventType: string): Promise<readonly SequenceDefinition[]>;
}

export interface SequenceTriggerDeps {
  readonly loader: SequenceTriggerLoader;
  readonly store: SequenceEngineStore & {
    rememberTrigger?: (trigger: SequenceTriggerContext | null) => void;
  };
  readonly queue: SequenceEngineQueue;
  readonly logger?: SequenceTriggerLogger;
  readonly now?: () => Date;
}

export interface SequenceTriggerJobResult {
  readonly normalisedEventType: string;
  readonly matched: number;
  readonly started: number;
  readonly skipped: number;
}

/**
 * Strip the `marketing.` prefix so an outbox event-type like
 * `marketing.lead.captured` matches a sequence whose `triggerEvent` is
 * the bare `lead.captured`. We also unify the dashed
 * `marketing.lead.convertedtotrial` (no underscore — that is what the
 * dispatcher emits today) to the documented `lead.converted_to_trial`.
 */
export function normaliseTriggerEventType(eventType: string): string {
  const trimmed = eventType.startsWith("marketing.") ? eventType.slice("marketing.".length) : eventType;
  switch (trimmed) {
    case "lead.convertedtotrial":
      return "lead.converted_to_trial";
    case "lead.convertedtocustomer":
      return "lead.converted_to_customer";
    default:
      return trimmed;
  }
}

export function parseSequenceTriggerJob(data: unknown): SequenceTriggerJobData {
  if (!data || typeof data !== "object") {
    throw new SequenceTriggerJobError("trigger job missing data envelope", "INVALID_PAYLOAD");
  }
  const e = data as Record<string, unknown>;
  const eventType = typeof e.eventType === "string" ? e.eventType : "";
  if (eventType.length === 0) {
    throw new SequenceTriggerJobError("trigger job missing eventType", "INVALID_PAYLOAD");
  }
  if (!SEQUENCE_TRIGGER_EVENT_TYPES.includes(eventType)) {
    throw new SequenceTriggerJobError(`unsupported event-type: ${eventType}`, "UNKNOWN_EVENT_TYPE");
  }
  const payload = e.payload;
  if (!payload || typeof payload !== "object") {
    throw new SequenceTriggerJobError("trigger job missing payload", "INVALID_PAYLOAD");
  }
  return {
    outboxEventId: typeof e.outboxEventId === "string" ? e.outboxEventId : undefined,
    tenantId: typeof e.tenantId === "string" ? e.tenantId : null,
    eventType,
    payload: payload as Readonly<Record<string, unknown>>,
  };
}

function extractEmail(payload: Readonly<Record<string, unknown>>): string | null {
  const direct = payload["email"];
  if (typeof direct === "string" && direct.includes("@")) return direct;
  const lead = payload["lead"];
  if (lead && typeof lead === "object") {
    const leadEmail = (lead as Record<string, unknown>)["email"];
    if (typeof leadEmail === "string" && leadEmail.includes("@")) return leadEmail;
  }
  const tenant = payload["tenant"];
  if (tenant && typeof tenant === "object") {
    const tenantEmail = (tenant as Record<string, unknown>)["email"];
    if (typeof tenantEmail === "string" && tenantEmail.includes("@")) return tenantEmail;
  }
  return null;
}

function extractLeadId(payload: Readonly<Record<string, unknown>>): string | null {
  const direct = payload["leadId"];
  if (typeof direct === "string" && direct) return direct;
  const lead = payload["lead"];
  if (lead && typeof lead === "object") {
    const id = (lead as Record<string, unknown>)["id"];
    if (typeof id === "string" && id) return id;
  }
  return null;
}

function extractTenantId(payload: Readonly<Record<string, unknown>>, fallback: string | null): string | null {
  const direct = payload["tenantId"];
  if (typeof direct === "string" && direct) return direct;
  const tenant = payload["tenant"];
  if (tenant && typeof tenant === "object") {
    const id = (tenant as Record<string, unknown>)["id"];
    if (typeof id === "string" && id) return id;
  }
  return fallback;
}

function extractRecipientName(payload: Readonly<Record<string, unknown>>): string | null {
  const direct = payload["recipientName"] ?? payload["firstName"];
  if (typeof direct === "string" && direct) return direct;
  const lead = payload["lead"];
  if (lead && typeof lead === "object") {
    const firstName = (lead as Record<string, unknown>)["firstName"];
    if (typeof firstName === "string" && firstName) return firstName;
  }
  return null;
}

/**
 * Main handler entry point. Looks up matching sequences and starts a
 * run for each. Per-sequence failures are isolated so one bad
 * definition cannot block the others.
 */
export async function runSequenceTriggerJob(
  data: unknown,
  deps: SequenceTriggerDeps
): Promise<SequenceTriggerJobResult> {
  if (process.env.MARKETING_SEQUENCES_ENABLED !== "true") {
    deps.logger?.info?.({ op: "sequence.trigger.skipped" }, "email sequences disabled by env");
    return { normalisedEventType: "(disabled)", matched: 0, started: 0, skipped: 0 };
  }
  const job = parseSequenceTriggerJob(data);
  const normalised = normaliseTriggerEventType(job.eventType);
  const email = extractEmail(job.payload);
  if (!email) {
    deps.logger?.warn?.(
      { op: "sequence.trigger.no_email", eventType: job.eventType, outboxEventId: job.outboxEventId },
      "trigger payload missing recipient email — cannot enrol any sequence"
    );
    return { normalisedEventType: normalised, matched: 0, started: 0, skipped: 0 };
  }

  const sequences = await deps.loader.listEnabledForEvent(normalised);
  if (sequences.length === 0) {
    deps.logger?.info?.({ op: "sequence.trigger.no_match", eventType: normalised }, "no enabled sequences match event");
    return { normalisedEventType: normalised, matched: 0, started: 0, skipped: 0 };
  }

  const trigger: SequenceTriggerContext = {
    triggerEventId: job.outboxEventId ?? null,
    leadId: extractLeadId(job.payload),
    tenantId: extractTenantId(job.payload, job.tenantId ?? null),
    email,
    recipientName: extractRecipientName(job.payload),
    payload: job.payload,
  };

  let started = 0;
  let skipped = 0;
  for (const sequence of sequences) {
    try {
      deps.store.rememberTrigger?.(trigger);
      const result = await startSequenceRun(
        { sequence, trigger },
        { store: deps.store, queue: deps.queue, logger: deps.logger, now: deps.now }
      );
      if (result.scheduled) started += 1;
      else skipped += 1;
      deps.logger?.info?.(
        {
          op: result.scheduled ? "sequence.trigger.started" : "sequence.trigger.skipped",
          sequenceId: sequence.id,
          runId: result.run.id || null,
          alreadyExisted: result.alreadyExisted,
        },
        result.scheduled ? "sequence run started" : "sequence run not scheduled"
      );
    } catch (error) {
      skipped += 1;
      deps.logger?.error(
        {
          op: "sequence.trigger.error",
          sequenceId: sequence.id,
          error: error instanceof Error ? error.message : String(error),
        },
        "sequence run failed to start"
      );
    }
  }
  return { normalisedEventType: normalised, matched: sequences.length, started, skipped };
}