import { ExportStatus, Prisma } from "@prisma/client";
import { db } from "@/lib/db";
import { PipelineError } from "./errors";
import { renderManifestSchema, type RenderManifest } from "./manifest";
import { applyTransition, type TransitionActor } from "./transitions";
import { getConfigNumber, getConfigValue } from "./config";

/** Statuses in which a shot has a live export in flight (§6.4 E1 409 rule). */
const ACTIVE_STATUSES: ExportStatus[] = [
  "QUEUED",
  "RENDERING",
  "VALIDATING",
  "GENERATING_PREVIEW",
];

/** Non-terminal statuses auto-superseded when a newer Export is queued (T1/T17). */
const SUPERSEDABLE_STATUSES: ExportStatus[] = [
  "QUEUED",
  "RENDER_FAILED",
  "VALIDATION_FAILED",
  "PREVIEW_FAILED",
  "READY_FOR_QC",
  "QC_FAILED",
  "READY_FOR_DELIVERY",
];

const OPEN_JOB_STATUSES = ["QUEUED", "CLAIMED", "RUNNING"] as const;

export function parseVersionString(v: string | null | undefined): number {
  const m = /^v(\d+)$/i.exec(v?.trim() ?? "");
  return m ? parseInt(m[1], 10) : 0;
}

export function formatVersionString(n: number): string {
  return `v${String(n).padStart(3, "0")}`;
}

/** `UNG_..._cmp_TT_v003` + 4 → `UNG_..._cmp_TT_v004`; falls back to house convention. */
function nextExrOutputBase(current: string | null, shotCode: string, versionString: string): string {
  if (current && /_v\d+$/i.test(current)) return current.replace(/_v\d+$/i, `_${versionString}`);
  if (current) return `${current}_${versionString}`;
  return renderOutputBase(shotCode, versionString);
}

/**
 * Rendered EXR naming for the pipeline — matches the panel's
 * "Queue EXR (Review)" convention (`{shotCode}_cmp_TT_{version}`), which is
 * shot-code based and deliberately excludes the source clip name that
 * `Shot.exrOutput` carries from the EDL import.
 */
function renderOutputBase(shotCode: string, versionString: string): string {
  return `${shotCode}_cmp_TT_${versionString}`;
}

export interface CreateExportInput {
  manifest: unknown;
  submittedByEmail?: string | null;
  priority?: number;
  force?: boolean;
  /**
   * Per-submission slate fields. `undefined` inherits the previous export's
   * value for this shot; `null` or "" explicitly clears it.
   */
  vfxScope?: string | null;
  submissionNote?: string | null;
}

/**
 * E1 — Queue Export (§6.4). Transactionally: decides the new version number
 * (server-side, race-free), updates Shot.shotVersion/exrOutput exactly as the
 * panel's legacy PATCH did, supersedes older non-terminal exports, creates
 * Export(QUEUED) + RenderJob attempt 1 with the manifest snapshot.
 */
export async function createExport(input: CreateExportInput) {
  const parsed = renderManifestSchema.safeParse(input.manifest);
  if (!parsed.success) {
    throw new PipelineError(422, "Manifest validation error", parsed.error.issues);
  }
  const manifest = parsed.data;

  const shot = await db.shot.findUnique({
    where: { id: manifest.shotId },
    include: {
      project: { select: { id: true, code: true, showId: true } },
      tasks: { where: { type: "COMP" }, orderBy: { sortOrder: "asc" }, take: 1, select: { id: true } },
    },
  });
  if (!shot) throw new PipelineError(404, `Shot not found: ${manifest.shotId}`);

  // Cross-checks (§6.2): manifest vs DB truth
  if (shot.shotCode !== manifest.shotCode) {
    throw new PipelineError(422, `Manifest shotCode "${manifest.shotCode}" does not match shot ${shot.id} ("${shot.shotCode}")`);
  }
  if (shot.project.code !== manifest.projectCode) {
    throw new PipelineError(422, `Manifest projectCode "${manifest.projectCode}" does not match shot's project ("${shot.project.code}")`);
  }
  // A 0/0 shot range means "never imported", not a real single-frame shot at 0
  const shotRangeKnown =
    shot.frameStart != null && shot.frameEnd != null && !(shot.frameStart === 0 && shot.frameEnd === 0);
  if (
    !input.force &&
    shotRangeKnown &&
    (shot.frameStart !== manifest.frameStart || shot.frameEnd !== manifest.frameEnd)
  ) {
    throw new PipelineError(422, `Manifest frame range ${manifest.frameStart}-${manifest.frameEnd} does not match shot record ${shot.frameStart}-${shot.frameEnd} (pass force to override)`);
  }

  const activeExport = await db.export.findFirst({
    where: { shotId: shot.id, status: { in: ACTIVE_STATUSES } },
    select: { id: true, status: true, versionString: true },
  });
  if (activeExport && !input.force) {
    throw new PipelineError(
      409,
      `An active export (${activeExport.versionString}, ${activeExport.status}) already exists for this shot — pass force to supersede it`,
      { activeExportId: activeExport.id }
    );
  }

  const submittedBy = input.submittedByEmail
    ? await db.user.findUnique({ where: { email: input.submittedByEmail }, select: { id: true, name: true } })
    : null;

  const [maxAttempts, outputRoot] = await Promise.all([
    getConfigNumber("render.maxAttempts"),
    getConfigValue("render.outputRoot"),
  ]);

  // Retry loop: @@unique([shotId, versionNumber]) guards the version-increment
  // race between two concurrent E1 calls; loser recomputes and retries.
  for (let tryNo = 0; tryNo < 3; tryNo++) {
    try {
      return await db.$transaction(async (tx) => {
        const latest = await tx.export.aggregate({
          where: { shotId: shot.id },
          _max: { versionNumber: true },
        });
        const freshShot = await tx.shot.findUniqueOrThrow({
          where: { id: shot.id },
          select: { shotVersion: true, exrOutput: true, slateVfxScope: true, slateSubmissionNote: true },
        });
        // vfxScope: caller override → shot's slate field
        const vfxScope = input.vfxScope !== undefined ? input.vfxScope : (freshShot.slateVfxScope ?? null);
        // submissionNote: caller override (per-export) → shot's slate default
        const submissionNote =
          input.submissionNote !== undefined ? input.submissionNote : (freshShot.slateSubmissionNote ?? null);
        // versionNumber is an internal sequence for DB uniqueness only; output files
        // use the shot's current (manually-set) shotVersion.
        const versionNumber = (latest._max.versionNumber ?? 0) + 1;
        const versionString = freshShot.shotVersion ?? formatVersionString(versionNumber);
        const exrBase = nextExrOutputBase(freshShot.exrOutput, shot.shotCode, versionString);

        const outputDir =
          manifest.outputDir === "auto"
            ? [outputRoot, shot.project.code, ...(shot.episode ? [shot.episode] : []), shot.shotCode, versionString].join("/")
            : manifest.outputDir;
        const outputPattern =
          manifest.outputPattern === "auto"
            ? `${renderOutputBase(shot.shotCode, versionString)}.[#####].exr`
            : manifest.outputPattern;

        const resolvedManifest: RenderManifest = { ...manifest, outputDir, outputPattern };

        // Supersede older non-terminal exports (T1/T17); cancel their open jobs.
        const toSupersede = await tx.export.findMany({
          where: {
            shotId: shot.id,
            status: { in: input.force ? [...SUPERSEDABLE_STATUSES, ...ACTIVE_STATUSES] : SUPERSEDABLE_STATUSES },
          },
          select: { id: true, status: true },
        });

        const created = await tx.export.create({
          data: {
            shotId: shot.id,
            projectId: shot.project.id,
            taskId: shot.tasks[0]?.id ?? null,
            versionNumber,
            versionString,
            status: "QUEUED",
            aepPath: manifest.aepPath,
            compName: manifest.compName,
            rendererType: manifest.rendererType,
            outputDir,
            outputPattern,
            frameStart: manifest.frameStart,
            frameEnd: manifest.frameEnd,
            fps: manifest.fps,
            width: manifest.width,
            height: manifest.height,
            colorspace: manifest.expected?.colorspace ?? null,
            vfxScope,
            submissionNote,
            submittedById: submittedBy?.id ?? null,
            submittedByName: submittedBy?.name ?? input.submittedByEmail ?? null,
          },
        });

        for (const old of toSupersede) {
          await tx.renderJob.updateMany({
            where: { exportId: old.id, status: { in: [...OPEN_JOB_STATUSES] } },
            data: { status: "CANCELLED", finishedAt: new Date(), errorMessage: `Superseded by export ${created.id} (${versionString})` },
          });
          await applyTransition(
            tx,
            old,
            "SUPERSEDED",
            { type: "SYSTEM", note: `Superseded by ${versionString}` },
            { supersededById: created.id }
          );
        }

        const renderJob = await tx.renderJob.create({
          data: {
            type: "AE_RENDER",
            exportId: created.id,
            attempt: 1,
            maxAttempts,
            priority: input.priority ?? 50,
            manifest: resolvedManifest as unknown as Prisma.InputJsonValue,
          },
        });

        await tx.exportEvent.create({
          data: {
            exportId: created.id,
            fromStatus: null,
            toStatus: "QUEUED",
            actorType: "USER",
            actorId: submittedBy?.id ?? null,
            note: `Queue Export ${versionString}${input.force ? " (force)" : ""}`,
          },
        });

        return {
          export: {
            id: created.id,
            shotCode: shot.shotCode,
            versionNumber,
            versionString,
            status: created.status,
            outputDir,
            outputPattern,
            vfxScope,
            submissionNote,
          },
          renderJob: { id: renderJob.id, attempt: renderJob.attempt, priority: renderJob.priority },
          shot: { id: shot.id, shotVersion: versionString, exrOutput: exrBase },
          superseded: toSupersede.map((s) => s.id),
        };
      });
    } catch (err) {
      if (err instanceof Prisma.PrismaClientKnownRequestError && err.code === "P2002" && tryNo < 2) {
        continue; // concurrent E1 won the version — recompute
      }
      throw err;
    }
  }
  throw new PipelineError(409, "Could not allocate a version number after retries");
}

function serializeExport<T extends { exrTotalBytes: bigint | null }>(e: T) {
  return { ...e, exrTotalBytes: e.exrTotalBytes == null ? null : Number(e.exrTotalBytes) };
}

/** E2 — latest export + status for the AE panel header (§6.4). */
export async function getLatestExport(shotCode: string, projectCode?: string | null) {
  const shot = await db.shot.findFirst({
    where: { shotCode, ...(projectCode ? { project: { code: projectCode } } : {}) },
    select: { id: true },
  });
  if (!shot) throw new PipelineError(404, "Shot not found");

  const exp = await db.export.findFirst({
    where: { shotId: shot.id },
    orderBy: { versionNumber: "desc" },
    include: {
      renderJobs: {
        orderBy: { attempt: "desc" },
        take: 1,
        include: { machine: { select: { name: true } } },
      },
    },
  });
  if (!exp) return { export: null };

  const job = exp.renderJobs[0] ?? null;
  return {
    export: {
      id: exp.id,
      versionNumber: exp.versionNumber,
      versionString: exp.versionString,
      status: exp.status,
      statusChangedAt: exp.statusChangedAt,
      outputDir: exp.outputDir,
      outputPattern: exp.outputPattern,
      // Panel prefills its slate fields from these
      vfxScope: exp.vfxScope,
      submissionNote: exp.submissionNote,
      renderJob: job
        ? {
            id: job.id,
            attempt: job.attempt,
            status: job.status,
            progress: job.progress,
            currentFrame: job.currentFrame,
            totalFrames: job.totalFrames,
            etaSeconds: job.etaSeconds,
            errorMessage: job.errorMessage,
            machineName: job.machine?.name ?? null,
          }
        : null,
      previewUrl: exp.previewMovKey ? `/api/files/${exp.previewMovKey}` : null,
      thumbnailUrl: exp.thumbnailKey ? `/api/files/${exp.thumbnailKey}` : null,
    },
  };
}

/** E3 — export detail incl. attempts and audit events. */
export async function getExportDetail(exportId: string) {
  const exp = await db.export.findUnique({
    where: { id: exportId },
    include: {
      shot: { select: { id: true, shotCode: true, episode: true, project: { select: { id: true, name: true, code: true } } } },
      renderJobs: {
        orderBy: { attempt: "asc" },
        include: { machine: { select: { id: true, name: true } } },
      },
      events: { orderBy: { createdAt: "asc" } },
    },
  });
  if (!exp) throw new PipelineError(404, "Export not found");
  return { export: serializeExport(exp) };
}

/**
 * E14 / E15 — retry a failed export: new RenderJob attempt, back to QUEUED.
 * PREVIEW_FAILED is routed to the preview-only retry (T11) so validated EXRs
 * are never re-rendered just to rebuild a slate.
 */
export async function retryExport(exportId: string, actor: TransitionActor) {
  const current = await db.export.findUnique({ where: { id: exportId }, select: { status: true } });
  if (!current) throw new PipelineError(404, "Export not found");
  if (current.status === "PREVIEW_FAILED") {
    const { retryPreview } = await import("./preview");
    return retryPreview(exportId, actor.id ?? undefined);
  }

  return db.$transaction(async (tx) => {
    const exp = await tx.export.findUnique({
      where: { id: exportId },
      include: { renderJobs: { orderBy: { attempt: "desc" }, take: 1 } },
    });
    if (!exp) throw new PipelineError(404, "Export not found");
    if (!["RENDER_FAILED", "VALIDATION_FAILED"].includes(exp.status)) {
      throw new PipelineError(409, `Export is ${exp.status} — only RENDER_FAILED, VALIDATION_FAILED or PREVIEW_FAILED exports can be retried`);
    }
    const last = exp.renderJobs[0];
    if (!last) throw new PipelineError(500, "Export has no render jobs");

    const job = await tx.renderJob.create({
      data: {
        type: last.type,
        exportId: exp.id,
        attempt: last.attempt + 1,
        maxAttempts: last.maxAttempts,
        priority: last.priority,
        manifest: last.manifest as Prisma.InputJsonValue,
      },
    });
    const updated = await applyTransition(tx, exp, "QUEUED", {
      ...actor,
      note: actor.note ?? `Retry (attempt ${job.attempt})`,
    });
    return { export: { id: updated.id, status: updated.status }, renderJob: { id: job.id, attempt: job.attempt } };
  });
}

/** E15 / T18 — cancel a queued or rendering export. Worker learns via heartbeat/progress. */
export async function cancelExport(exportId: string, actor: TransitionActor) {
  return db.$transaction(async (tx) => {
    const exp = await tx.export.findUnique({ where: { id: exportId }, select: { id: true, status: true } });
    if (!exp) throw new PipelineError(404, "Export not found");
    if (exp.status === "CANCELLED") return { export: exp, alreadyApplied: true };
    if (!["QUEUED", "RENDERING"].includes(exp.status)) {
      throw new PipelineError(409, `Export is ${exp.status} — only QUEUED or RENDERING exports can be cancelled`);
    }
    await tx.renderJob.updateMany({
      where: { exportId: exp.id, status: "QUEUED" },
      data: { status: "CANCELLED", finishedAt: new Date(), errorMessage: "Cancelled by user" },
    });
    // Claimed/running jobs stay marked CANCELLED but keep finishedAt null until
    // the worker acknowledges (heartbeat CANCEL_JOB command / progress cancelRequested)
    await tx.renderJob.updateMany({
      where: { exportId: exp.id, status: { in: ["CLAIMED", "RUNNING"] } },
      data: { status: "CANCELLED", errorMessage: "Cancelled by user" },
    });
    const updated = await applyTransition(tx, exp, "CANCELLED", actor);
    return { export: { id: updated.id, status: updated.status }, alreadyApplied: false };
  });
}

/**
 * Phase 1 stopgap (§17.1): admin "mark as done manually" so the studio can
 * keep using the old render path while the queue is validated. Removed once
 * workers render for real.
 */
export async function markExportDoneManually(exportId: string, userId: string, note?: string) {
  return db.$transaction(async (tx) => {
    const exp = await tx.export.findUnique({ where: { id: exportId }, select: { id: true, status: true } });
    if (!exp) throw new PipelineError(404, "Export not found");
    if (!["QUEUED", "RENDERING"].includes(exp.status)) {
      throw new PipelineError(409, `Export is ${exp.status} — only QUEUED or RENDERING exports can be marked done`);
    }
    await tx.renderJob.updateMany({
      where: { exportId: exp.id, status: { in: [...OPEN_JOB_STATUSES] } },
      data: { status: "CANCELLED", finishedAt: new Date(), errorMessage: "Manually marked done (legacy render path)" },
    });
    const updated = await applyTransition(tx, exp, "READY_FOR_QC", {
      type: "USER",
      id: userId,
      note: note ?? "Manually marked done (rendered outside the pipeline)",
    });
    return { export: { id: updated.id, status: updated.status } };
  });
}

export interface ListExportsFilter {
  projectId?: string;
  episode?: string;
  status?: ExportStatus;
  shotId?: string;
  page?: number;
  limit?: number;
}

/** E21 — paginated export list for the web queue/monitoring pages. */
export async function listExports(filter: ListExportsFilter) {
  const page = Math.max(1, filter.page ?? 1);
  const limit = Math.min(200, Math.max(1, filter.limit ?? 50));
  const where: Prisma.ExportWhereInput = {
    ...(filter.projectId ? { projectId: filter.projectId } : {}),
    ...(filter.status ? { status: filter.status } : {}),
    ...(filter.shotId ? { shotId: filter.shotId } : {}),
    ...(filter.episode ? { shot: { episode: filter.episode } } : {}),
  };
  const [total, rows] = await Promise.all([
    db.export.count({ where }),
    db.export.findMany({
      where,
      orderBy: { createdAt: "desc" },
      skip: (page - 1) * limit,
      take: limit,
      include: {
        shot: { select: { shotCode: true, episode: true, project: { select: { name: true, code: true } } } },
        renderJobs: {
          orderBy: { attempt: "desc" },
          take: 1,
          include: { machine: { select: { name: true } } },
        },
      },
    }),
  ]);
  return {
    pagination: { page, limit, total, pages: Math.ceil(total / limit) },
    exports: rows.map((e) => ({
      id: e.id,
      shotCode: e.shot.shotCode,
      episode: e.shot.episode,
      projectName: e.shot.project.name,
      projectCode: e.shot.project.code,
      versionString: e.versionString,
      status: e.status,
      statusChangedAt: e.statusChangedAt,
      createdAt: e.createdAt,
      outputDir: e.outputDir,
      job: e.renderJobs[0]
        ? {
            id: e.renderJobs[0].id,
            attempt: e.renderJobs[0].attempt,
            status: e.renderJobs[0].status,
            progress: e.renderJobs[0].progress,
            currentFrame: e.renderJobs[0].currentFrame,
            totalFrames: e.renderJobs[0].totalFrames,
            etaSeconds: e.renderJobs[0].etaSeconds,
            priority: e.renderJobs[0].priority,
            machineName: e.renderJobs[0].machine?.name ?? null,
            errorMessage: e.renderJobs[0].errorMessage,
          }
        : null,
    })),
  };
}