import { Prisma } from "@capakraken/db";
import { TRPCError } from "@trpc/server";
import { z } from "zod";
import type { TRPCContext } from "../trpc.js";
import {
  type EntityKey,
  ReportTemplateConfigSchema,
  validateReportInput,
} from "./report-query-config.js";

const ReportTemplateEntity = {
  RESOURCE: "RESOURCE",
  PROJECT: "PROJECT",
  ASSIGNMENT: "ASSIGNMENT",
  RESOURCE_MONTH: "RESOURCE_MONTH",
} as const;

type ReportTemplateEntity = (typeof ReportTemplateEntity)[keyof typeof ReportTemplateEntity];

type ReportTemplateRecord = {
  id: string;
  name: string;
  description: string | null;
  entity: ReportTemplateEntity;
  config: unknown;
  isShared: boolean;
  ownerId: string;
  updatedAt: Date;
};

type ReportTemplateContext = Pick<TRPCContext, "db" | "dbUser">;

export const SaveReportTemplateInputSchema = z.object({
  id: z.string().optional(),
  name: z.string().trim().min(1).max(120),
  description: z.string().trim().max(500).optional(),
  isShared: z.boolean().default(false),
  config: ReportTemplateConfigSchema,
});

export const DeleteReportTemplateInputSchema = z.object({
  id: z.string(),
});

export async function listReportTemplates(ctx: ReportTemplateContext) {
  const ownerId = ctx.dbUser!.id;
  const templates = await ctx.db.reportTemplate.findMany({
    where: {
      OR: [
        { ownerId },
        { isShared: true },
      ],
    },
    orderBy: [{ name: "asc" }],
    select: {
      id: true,
      name: true,
      description: true,
      entity: true,
      config: true,
      isShared: true,
      ownerId: true,
      updatedAt: true,
    },
  });

  return templates.map((template) => mapTemplateRecord(template, ownerId));
}

export async function saveReportTemplate(
  ctx: ReportTemplateContext,
  input: z.infer<typeof SaveReportTemplateInputSchema>,
) {
  const ownerId = ctx.dbUser!.id;
  validateReportInput(input.config);
  const payload = input.config as unknown as Prisma.InputJsonValue;
  const entity = toTemplateEntity(input.config.entity);
  const writeData = buildTemplateWriteData(input, entity, payload);

  if (input.id) {
    const existing = await ctx.db.reportTemplate.findUnique({
      where: { id: input.id },
      select: { ownerId: true },
    });

    if (!existing || existing.ownerId !== ownerId) {
      throw new TRPCError({ code: "FORBIDDEN", message: "Template cannot be updated" });
    }

    return ctx.db.reportTemplate.update({
      where: { id: input.id },
      data: writeData,
      select: { id: true, updatedAt: true },
    });
  }

  return ctx.db.reportTemplate.upsert({
    where: {
      ownerId_name: {
        ownerId,
        name: input.name,
      },
    },
    update: omitNameFromTemplateWriteData(writeData),
    create: {
      ownerId,
      ...writeData,
    },
    select: { id: true, updatedAt: true },
  });
}

export async function deleteReportTemplate(
  ctx: ReportTemplateContext,
  input: z.infer<typeof DeleteReportTemplateInputSchema>,
) {
  const ownerId = ctx.dbUser!.id;
  const existing = await ctx.db.reportTemplate.findUnique({
    where: { id: input.id },
    select: { ownerId: true },
  });

  if (!existing || existing.ownerId !== ownerId) {
    throw new TRPCError({ code: "FORBIDDEN", message: "Template cannot be deleted" });
  }

  await ctx.db.reportTemplate.delete({ where: { id: input.id } });
  return { ok: true };
}

function buildTemplateWriteData(
  input: z.infer<typeof SaveReportTemplateInputSchema>,
  entity: ReportTemplateEntity,
  config: Prisma.InputJsonValue,
) {
  return {
    name: input.name,
    entity,
    config,
    isShared: input.isShared,
    ...(input.description !== undefined ? { description: input.description } : {}),
  };
}

function omitNameFromTemplateWriteData(
  data: ReturnType<typeof buildTemplateWriteData>,
) {
  const { name: _name, ...updateData } = data;
  return updateData;
}

function mapTemplateRecord(template: ReportTemplateRecord, ownerId: string) {
  return {
    id: template.id,
    name: template.name,
    description: template.description,
    entity: fromTemplateEntity(template.entity),
    config: ReportTemplateConfigSchema.parse(template.config),
    isShared: template.isShared,
    isOwner: template.ownerId === ownerId,
    updatedAt: template.updatedAt,
  };
}

function toTemplateEntity(entity: EntityKey): ReportTemplateEntity {
  switch (entity) {
    case "resource":
      return ReportTemplateEntity.RESOURCE;
    case "project":
      return ReportTemplateEntity.PROJECT;
    case "assignment":
      return ReportTemplateEntity.ASSIGNMENT;
    case "resource_month":
      return ReportTemplateEntity.RESOURCE_MONTH;
    default:
      throw new TRPCError({ code: "BAD_REQUEST", message: `Unknown entity: ${entity}` });
  }
}

function fromTemplateEntity(entity: ReportTemplateEntity): EntityKey {
  switch (entity) {
    case ReportTemplateEntity.RESOURCE:
      return "resource";
    case ReportTemplateEntity.PROJECT:
      return "project";
    case ReportTemplateEntity.ASSIGNMENT:
      return "assignment";
    case ReportTemplateEntity.RESOURCE_MONTH:
      return "resource_month";
    default:
      throw new TRPCError({ code: "BAD_REQUEST", message: `Unknown entity: ${entity}` });
  }
}