import { z } from "zod";
import { Prisma } from "@prisma/client";
import type { AssetAttributeDataType } from "./asset-category-attribute-defs";
import { prisma } from "./prisma";

export interface AssetModelRecord {
  id: string;
  category_id: string;
  manufacturer: string;
  name: string;
  specs: Record<string, unknown>;
  warranty_months: number | null;
  created_at: string;
}

export interface CreateAssetModelInput {
  categoryId: string;
  manufacturer: string;
  name: string;
  specs: Record<string, unknown>;
  warrantyMonths?: number | null;
}

export type ValidationResult =
  | { ok: true; value: CreateAssetModelInput }
  | { ok: false; error: string };

// Mirrors src/lib/asset-category-attribute-defs.ts's nonEmptyString helper.
function nonEmptyString(message: string) {
  return z.string({ required_error: message, invalid_type_error: message }).refine(
    (value) => value.trim() !== "",
    { message }
  );
}

const createAssetModelSchema = z.object({
  // FK to AssetCategory — only a UUID *format* check here, whether it
  // references a real category (and whether that category is
  // valueGroup=high_value) is left to createAssetModel()'s explicit lookup
  // below — that's a business rule, not something pure Zod schema
  // validation on this input alone can express. Mirrors
  // src/lib/asset-category-attribute-defs.ts's categoryId handling.
  categoryId: z
    .string({ required_error: "categoryId is required and must be a valid UUID string" })
    .uuid("categoryId is required and must be a valid UUID string"),
  manufacturer: nonEmptyString("manufacturer is required and must be a non-empty string"),
  name: nonEmptyString("name is required and must be a non-empty string"),
  // Deliberately LOOSE at this stage — just "a plain JSON object" (no
  // arrays, no primitives at the top level). The category-specific dynamic
  // shape (which keys are allowed, which are required, and their types) is
  // validated separately in createAssetModel() below, via a runtime Zod
  // schema built from that category's AssetCategoryAttributeDef rows — it
  // can't be done here because that requires a DB lookup keyed on
  // categoryId, which this pure-input-shape schema doesn't have access to.
  // Defaults to {} when omitted, matching the DB column default.
  specs: z
    .record(z.unknown(), {
      invalid_type_error: "specs must be a JSON object",
    })
    .optional()
    .default({}),
  // Optional standard warranty length -- see schema.prisma's
  // AssetModel.warrantyMonths comment for what this drives.
  warrantyMonths: z
    .number({ invalid_type_error: "warrantyMonths must be a positive integer" })
    .int("warrantyMonths must be a positive integer")
    .positive("warrantyMonths must be a positive integer")
    .optional()
    .nullable(),
});

/**
 * Validates raw (untyped) asset-model-creation input. categoryId must be a
 * valid UUID string, manufacturer/name must be non-empty strings, specs
 * must be a plain JSON object (or omitted, defaulting to {}). Whether
 * categoryId references a real, high_value AssetCategory is checked in
 * createAssetModel() below, not here — that requires a DB lookup.
 */
export function validateCreateAssetModelInput(input: {
  categoryId?: unknown;
  manufacturer?: unknown;
  name?: unknown;
  specs?: unknown;
  warrantyMonths?: unknown;
}): ValidationResult {
  const result = createAssetModelSchema.safeParse(input);
  if (!result.success) {
    const message = result.error.issues[0]?.message ?? "Invalid input";
    return { ok: false, error: message };
  }
  return { ok: true, value: result.data };
}

function toRecord(row: {
  id: string;
  categoryId: string;
  manufacturer: string;
  name: string;
  specs: Prisma.JsonValue;
  warrantyMonths: number | null;
  createdAt: Date;
}): AssetModelRecord {
  return {
    id: row.id,
    category_id: row.categoryId,
    manufacturer: row.manufacturer,
    name: row.name,
    specs: (row.specs as Record<string, unknown>) ?? {},
    warranty_months: row.warrantyMonths,
    created_at: row.createdAt.toISOString(),
  };
}

// Maps an AssetCategoryAttributeDef.dataType to the corresponding Zod leaf
// type, per docs/asset-license-management.md's "Cập nhật 2026-08-02 (3)"
// section: string -> z.string(), number -> z.number(), boolean ->
// z.boolean(), date -> z.coerce.date() (coerce so a JSON-transported date
// *string*, e.g. "2027-01-01", is accepted — JSON has no native Date type).
function zodTypeForDataType(dataType: AssetAttributeDataType): z.ZodTypeAny {
  switch (dataType) {
    case "string":
      return z.string();
    case "number":
      return z.number();
    case "boolean":
      return z.boolean();
    case "date":
      return z.coerce.date();
  }
}

/**
 * Builds a Zod object schema AT RUNTIME from a category's
 * AssetCategoryAttributeDef rows: one shape entry per attribute def (typed
 * per zodTypeForDataType() above), optional when `required` is false via
 * `.optional()`, and `.strict()` on the overall object so any `specs` key
 * not defined for this category is rejected (no unknown keys allowed), per
 * the doc section referenced above.
 */
function buildSpecsSchema(
  attributeDefs: { key: string; dataType: AssetAttributeDataType; required: boolean }[]
): z.ZodTypeAny {
  const shape: Record<string, z.ZodTypeAny> = {};
  for (const def of attributeDefs) {
    const leaf = zodTypeForDataType(def.dataType);
    shape[def.key] = def.required ? leaf : leaf.optional();
  }
  return z.object(shape).strict();
}

export type CreateAssetModelResult =
  | { ok: true; value: AssetModelRecord }
  | { ok: false; error: string };

/**
 * Creates an AssetModel. categoryId must reference a real AssetCategory
 * (checked here via an explicit prisma.assetCategory.findUnique() lookup —
 * not left to Prisma's P2003 FK-violation catch like other entities'
 * simple FK checks, e.g. src/lib/asset-category-attribute-defs.ts's
 * categoryId handling), because there's an additional business rule to
 * enforce beyond "does this row exist": the referenced category's
 * valueGroup must be `high_value` (per docs/asset-license-management.md's
 * "Ràng buộc dữ liệu" section under "Cập nhật 2026-08-02 (2)") — a rule
 * that can't be expressed as a Postgres FK constraint, so it can't be
 * caught via a Prisma error code the way a plain missing-FK case can. If
 * the category doesn't exist at all, or exists but is `low_value`, this
 * returns a distinct {ok:false,error} for each case rather than a raw
 * P2003/500.
 */
export async function createAssetModel(
  input: CreateAssetModelInput
): Promise<CreateAssetModelResult> {
  const category = await prisma.assetCategory.findUnique({
    where: { id: input.categoryId },
  });

  if (!category) {
    return { ok: false, error: "categoryId does not reference an existing asset category" };
  }

  if (category.valueGroup !== "high_value") {
    return { ok: false, error: "categoryId must reference a category with valueGroup=high_value" };
  }

  // Dynamic specs validation, per docs/asset-license-management.md's
  // "Cập nhật 2026-08-02 (3)" section: build a Zod schema at runtime from
  // this category's AssetCategoryAttributeDef rows, and validate the
  // incoming specs object against it. Deliberately done here (after the
  // category existence/high_value checks above), not inside
  // validateCreateAssetModelInput()'s static schema, because it needs a DB
  // lookup keyed on categoryId.
  const attributeDefs = await prisma.assetCategoryAttributeDef.findMany({
    where: { categoryId: input.categoryId },
  });
  const specsSchema = buildSpecsSchema(attributeDefs);
  const specsResult = specsSchema.safeParse(input.specs);
  if (!specsResult.success) {
    const message = specsResult.error.issues[0]?.message ?? "Invalid specs";
    const path = specsResult.error.issues[0]?.path.join(".");
    return {
      ok: false,
      error: path ? `specs.${path}: ${message}` : `specs: ${message}`,
    };
  }

  const created = await prisma.assetModel.create({
    data: {
      categoryId: input.categoryId,
      manufacturer: input.manufacturer,
      name: input.name,
      // input.specs is validated by Zod to be a plain JSON object
      // (Record<string, unknown>), but Prisma's generated InputJsonValue
      // type doesn't structurally accept an index-signature Record — cast
      // is safe here since the Zod schema already guarantees JSON-shaped
      // values.
      specs: input.specs as Prisma.InputJsonValue,
      warrantyMonths: input.warrantyMonths ?? null,
    },
  });
  return { ok: true, value: toRecord(created) };
}

export async function listAssetModels(): Promise<AssetModelRecord[]> {
  const rows = await prisma.assetModel.findMany({
    orderBy: [{ createdAt: "desc" }, { id: "desc" }],
  });
  return rows.map(toRecord);
}