import { and, desc, eq, getTableColumns, ilike, or } from "drizzle-orm"
import * as tables from "../../../db/schema"
import { assertToolPermission } from "../authz"
import { assertInternalDocumentAccess } from "../documentFiles"
import { idField, InputField, numericField, objectField, textField, uuidField } from "../masterdataFields"
import { limitFromArgs, offsetFromArgs, paginatedResult, paginationProperties } from "../pagination"
import { McpContext, McpTool } from "../types"
import { insertHistoryItem } from "../../utils/history"
import { recalculateServicePricesForTenant } from "../../modules/service-price-recalculation.service"

type ArchiveEntity = {
    label: string
    table: any
    /** Key used by the history log and the generic resource routes. */
    resource: string
    permission: string
    searchColumns: string[]
    uuid?: boolean
    internalDocuments?: boolean
}

const masterdata = (label: string, table: any, resource: string, namespace: string, searchColumns: string[], uuid = false): ArchiveEntity =>
    ({ label, table, resource, permission: `masterdata.${namespace}`, searchColumns, uuid })

/** Every entity the MCP can archive; restore checks the matching write permission. */
export const archiveEntities: Record<string, ArchiveEntity> = {
    customers: masterdata("Kunde", tables.customers, "customers", "customers", ["name", "customerNumber"]),
    vendors: masterdata("Lieferant", tables.vendors, "vendors", "vendors", ["name", "vendorNumber"]),
    contacts: masterdata("Kontakt", tables.contacts, "contacts", "contacts", ["fullName", "email"]),
    products: masterdata("Artikel", tables.products, "products", "products", ["name", "article_number"]),
    services: masterdata("Leistung", tables.services, "services", "services", ["name"]),
    cost_centres: masterdata("Kostenstelle", tables.costcentres, "costcentres", "cost_centres", ["name", "number"], true),
    branches: masterdata("Niederlassung", tables.branches, "branches", "branches", ["name", "number"]),
    teams: masterdata("Team", tables.teams, "teams", "teams", ["name"]),
    vehicles: masterdata("Fahrzeug", tables.vehicles, "vehicles", "vehicles", ["name", "license_plate"]),
    inventory_items: masterdata("Inventar", tables.inventoryitems, "inventoryitems", "inventory_items", ["name", "articleNumber"]),
    projects: { label: "Projekt", table: tables.projects, resource: "projects", permission: "organisation.projects", searchColumns: ["name", "projectNumber"] },
    events: { label: "Termin", table: tables.events, resource: "events", permission: "organisation.events", searchColumns: ["name"] },
    tasks: { label: "Aufgabe", table: tables.tasks, resource: "tasks", permission: "organisation.tasks", searchColumns: ["name"] },
    outgoing_documents: { label: "Ausgangsbeleg", table: tables.createddocuments, resource: "createddocuments", permission: "accounting.outgoing_documents", searchColumns: ["documentNumber", "title"] },
    incoming_invoices: { label: "Eingangsbeleg", table: tables.incominginvoices, resource: "incominginvoices", permission: "accounting.incoming_invoices", searchColumns: ["reference", "description"] },
    files: { label: "Datei", table: tables.files, resource: "files", permission: "documents", searchColumns: ["name"], uuid: true, internalDocuments: true },
}

const entityField: InputField = {
    schema: { type: "string", enum: Object.keys(archiveEntities), description: "Art des archivierten Datensatzes." },
    parse(value, path) {
        if (typeof value !== "string" || !Object.prototype.hasOwnProperty.call(archiveEntities, value)) throw new Error(`${path}: unbekannte Entität`)
        return value
    },
}
const entityIdField: InputField = {
    schema: { type: ["integer", "string"], description: "ID des Datensatzes; UUID bei cost_centres und files, sonst ganze Zahl." },
    parse: (value) => value,
}
const searchField: InputField = {
    schema: { type: "string", maxLength: 200, description: "Optionaler Suchtext, z. B. Name oder Nummer." },
    parse(value, path) {
        const text = textField().parse(value, path)
        if (text.length > 200) throw new Error(`${path}: maximal 200 Zeichen`)
        return text
    },
}
const listInput = objectField({
    entity: entityField,
    search: searchField,
    limit: { ...numericField(true, 1, 100), schema: paginationProperties.limit },
    offset: { ...numericField(true, 0), schema: paginationProperties.offset },
})
const restoreInput = objectField({ entity: entityField, id: entityIdField })

const columnKey = (table: any, ...names: string[]) => names.find((name) => name in getTableColumns(table))

/** asToolResult hides records flagged archived; archived rows are marked explicitly instead. */
const withoutArchivedFlag = ({ archived: _archived, path: _path, extractedText: _text, ...row }: Record<string, any>) => row

async function authorize(context: McpContext, tool: McpTool, entity: ArchiveEntity, access: "read" | "write") {
    assertToolPermission(context, { name: tool.name, requiredPermissions: [`${entity.permission}.${access}`] })
    if (entity.internalDocuments) await assertInternalDocumentAccess(context)
}

export function prepareArchiveRestoreInput(args: Record<string, unknown>) {
    const input = restoreInput.parse(args, "arguments")
    if (!input.entity) throw new Error("entity ist erforderlich")
    if (input.id === undefined || input.id === null) throw new Error("id ist erforderlich")
    const entity = archiveEntities[input.entity]
    return { key: input.entity as string, entity, id: (entity.uuid ? uuidField : idField).parse(input.id, "id") }
}

const listTool: McpTool = {
    name: "archive.entities.list",
    title: "Archivierte Einträge auflisten",
    description: "Listet archivierte Datensätze einer Entitätsart im aktiven Mandanten, zuletzt geänderte zuerst. IDs anschließend mit archive.entities.restore wiederherstellen.",
    // Checked per entity in the handler.
    requiredPermissions: [],
    inputSchema: { ...listInput.schema, required: ["entity"] },
    async handler(context, args) {
        const input = listInput.parse(args, "arguments")
        if (!input.entity) throw new Error("entity ist erforderlich")
        const entity = archiveEntities[input.entity]
        await authorize(context, listTool, entity, "read")
        const table = entity.table
        const conditions: any[] = [eq(table.tenant, context.tenantId), eq(table.archived, true)]
        if (input.search) {
            const pattern = `%${input.search.replace(/[\\%_]/g, "\\$&")}%`
            conditions.push(or(...entity.searchColumns.map((column) => ilike(table[column], pattern))))
        }
        const updatedAt = columnKey(table, "updatedAt", "updated_at")!
        const rows = await context.server.db.select().from(table).where(and(...conditions))
            .orderBy(desc(table[updatedAt]), desc(table.id)).limit(limitFromArgs(input) + 1).offset(offsetFromArgs(input))
        const result = paginatedResult(rows, input)
        return { ...result, entity: input.entity, rows: result.rows.map((row: any) => ({ ...withoutArchivedFlag(row), isArchived: true })) }
    },
}

const restoreTool: McpTool = {
    name: "archive.entities.restore",
    title: "Archivierten Eintrag wiederherstellen",
    description: `Stellt einen archivierten Datensatz im aktiven Mandanten wieder her (entity: ${Object.keys(archiveEntities).join(", ")}). Benötigt die Schreibberechtigung der jeweiligen Entität.`,
    requiredPermissions: [],
    readOnly: false,
    inputSchema: { ...restoreInput.schema, required: ["entity", "id"] },
    async handler(context, args) {
        const { key, entity, id } = prepareArchiveRestoreInput(args)
        await authorize(context, restoreTool, entity, "write")
        const table = entity.table
        return context.server.db.transaction(async (tx) => {
            const server = { ...context.server, db: tx } as unknown as McpContext["server"]
            const scope = and(eq(table.id, id), eq(table.tenant, context.tenantId))
            const [existing] = await tx.select().from(table).where(scope).limit(1).for("update")
            if (!existing) throw new Error(`${entity.label} nicht gefunden`)
            if (!existing.archived) throw new Error(`${entity.label} ist nicht archiviert`)
            const [result] = await tx.update(table).set({
                archived: false,
                [columnKey(table, "updatedAt", "updated_at")!]: new Date(),
                [columnKey(table, "updatedBy", "updated_by")!]: context.userId,
            }).where(scope).returning()
            if (["products", "services"].includes(entity.resource)) {
                await recalculateServicePricesForTenant(server, context.tenantId, context.userId)
            }
            await insertHistoryItem(server, {
                tenant_id: context.tenantId, created_by: context.userId, entity: entity.resource, entityId: result.id,
                action: "restored", oldVal: existing, newVal: result,
            })
            return { entity: key, id: result.id, success: true, action: "restored", record: withoutArchivedFlag(result) }
        })
    },
}

export const archiveTools: McpTool[] = [listTool, restoreTool]