import { ShotStatus, ShotApprovalStatus, TaskStatus } from "@prisma/client";
import { db } from "@/lib/db";
import type { PrismaClient } from "@prisma/client";

type TxClient = Omit<
  PrismaClient,
  "$connect" | "$disconnect" | "$on" | "$transaction" | "$use" | "$extends"
>;

/**
 * Derive shot status from tasks + shot-level approval fields.
 *
 * Priority order (highest → lowest):
 *  1. REVISIONS         — any task is CHANGES
 *  2. COMPLETE          — shotApprovalStatus === CLIENT_APPROVED
 *  3. CLIENT_REVIEW     — shotApprovalStatus === INTERNALLY_APPROVED && sharedWithClient
 *  4. READY_FOR_CLIENT  — shotApprovalStatus === INTERNALLY_APPROVED && !sharedWithClient
 *  5. IN_PROGRESS       — any task is TODO or IN_PROGRESS
 *  6. INTERNAL_REVIEW   — tasks exist but none blocking, approval still PENDING
 *  7. WAITING           — no tasks
 */
export function deriveShotStatus(
  tasks: { status: TaskStatus }[],
  shotApprovalStatus: ShotApprovalStatus,
  sharedWithClient: boolean
): ShotStatus {
  // 1. Changes requested — highest priority
  if (tasks.some((t) => t.status === "CHANGES")) return "REVISIONS";

  // 2. Client approved — terminal completion state
  if (shotApprovalStatus === "CLIENT_APPROVED") return "COMPLETE";

  // 3 & 4. Internally approved — client-facing states
  if (shotApprovalStatus === "INTERNALLY_APPROVED") {
    return sharedWithClient ? "CLIENT_REVIEW" : "READY_FOR_CLIENT";
  }

  // 5. Active work in progress (approval still PENDING)
  if (tasks.some((t) => t.status === "TODO" || t.status === "IN_PROGRESS")) {
    return "IN_PROGRESS";
  }

  // 6. All work done, awaiting internal approval
  if (tasks.length > 0) return "INTERNAL_REVIEW";

  // 7. No tasks yet
  return "WAITING";
}

/**
 * Query all tasks + approval fields for a shot, derive the correct ShotStatus,
 * and persist it. Accepts an optional Prisma transaction client (tx).
 */
export async function recalcShotStatus(
  shotId: string,
  tx?: TxClient
): Promise<void> {
  const client = tx ?? db;

  const [tasks, shot] = await Promise.all([
    client.task.findMany({
      where: { shotId },
      select: { status: true },
    }),
    client.shot.findUnique({
      where: { id: shotId },
      select: { shotApprovalStatus: true, sharedWithClient: true },
    }),
  ]);

  if (!shot) return;

  const newStatus = deriveShotStatus(tasks, shot.shotApprovalStatus, shot.sharedWithClient);

  await client.shot.update({
    where: { id: shotId },
    data: { status: newStatus },
  });
}

/**
 * New review material arrived on a shot, so any standing sign-off is stale.
 *
 * deriveShotStatus short-circuits on shotApprovalStatus: a CLIENT_APPROVED shot
 * reads COMPLETE and an INTERNALLY_APPROVED one reads READY_FOR_CLIENT no matter
 * what its tasks say. Without this, uploading a new version onto an approved
 * shot moved the task to INTERNAL_REVIEW and changed nothing visible — the shot
 * still read as signed off while carrying work nobody had looked at.
 *
 * sharedWithClient is left alone; clearing the approval is enough to pull the
 * shot back to INTERNAL_REVIEW, and revoking client access is a separate,
 * deliberate act (unshareFromClient).
 *
 * @returns true if a stale approval was actually cleared.
 */
export async function clearStaleShotApproval(
  client: TxClient,
  shotId: string
): Promise<boolean> {
  const shot = await client.shot.findUnique({
    where: { id: shotId },
    select: { shotApprovalStatus: true },
  });
  if (!shot || shot.shotApprovalStatus === "PENDING") return false;

  await client.shot.update({
    where: { id: shotId },
    data: { shotApprovalStatus: "PENDING" },
  });
  return true;
}

/**
 * Put a shot into revisions: clear its approval, unshare it, and mark the tasks
 * that need rework so the derivation lands on REVISIONS.
 *
 * The task selection is the subtle part. Marking every non-DONE task as CHANGES
 * matches nothing at all on the shot this is most often called for — one that is
 * out for client review precisely *because* all of its tasks are finished. That
 * left the shot deriving to INTERNAL_REVIEW and the change request with no
 * visible effect anywhere. So when nothing was picked up, the task behind the
 * shot's latest version is marked instead: that is the deliverable the reviewer
 * was actually looking at.
 *
 * @param taskId  Mark only this task (a reviewer calling out one specific task).
 * @returns ids of the tasks moved to CHANGES.
 */
export async function markShotForRevisions(
  client: TxClient,
  shotId: string,
  taskId?: string
): Promise<string[]> {
  await client.shot.update({
    where: { id: shotId },
    data: { shotApprovalStatus: "PENDING", sharedWithClient: false },
  });

  let changed: string[];

  if (taskId) {
    await client.task.update({ where: { id: taskId }, data: { status: "CHANGES" } });
    changed = [taskId];
  } else {
    const open = await client.task.findMany({
      where: { shotId, status: { not: "DONE" } },
      select: { id: true },
    });

    if (open.length > 0) {
      await client.task.updateMany({
        where: { shotId, status: { not: "DONE" } },
        data: { status: "CHANGES" },
      });
      changed = open.map((t) => t.id);
    } else {
      // Every task is DONE — reopen the one that produced what was reviewed.
      const latest = await client.version.findFirst({
        where: { task: { shotId } },
        orderBy: [{ isLatest: "desc" }, { createdAt: "desc" }],
        select: { taskId: true },
      });
      if (latest?.taskId) {
        await client.task.update({
          where: { id: latest.taskId },
          data: { status: "CHANGES" },
        });
        changed = [latest.taskId];
      } else {
        changed = [];
      }
    }
  }

  await recalcShotStatus(shotId, client);
  return changed;
}