import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { z } from "zod";
import { WaveClient } from "../services/wave-client.js";
import { WaveCustomer } from "../types.js";
import { DEFAULT_PAGE_SIZE, MAX_PAGE_SIZE } from "../constants.js";

interface CustomersData {
  business: {
    customers: {
      pageInfo: { currentPage: number; totalPages: number; totalCount: number };
      edges: Array<{ node: WaveCustomer }>;
    };
  };
}

interface CustomerData {
  business: { customer: WaveCustomer };
}

interface CustomerCreateData {
  customerCreate: {
    didSucceed: boolean;
    inputErrors: Array<{ code: string; message: string; path: string[] }>;
    customer?: WaveCustomer;
  };
}

interface CustomerPatchData {
  customerPatch: {
    didSucceed: boolean;
    inputErrors: Array<{ code: string; message: string; path: string[] }>;
    customer?: WaveCustomer;
  };
}

interface CustomerDeleteData {
  customerDelete: {
    didSucceed: boolean;
    inputErrors: Array<{ code: string; message: string; path: string[] }>;
  };
}

const CUSTOMER_FIELDS = `
  id name firstName lastName email
  currency { code }
  address {
    addressLine1 city postalCode
    country { name code }
  }
  createdAt modifiedAt
`;

function formatCustomerMarkdown(c: WaveCustomer): string[] {
  const lines = [`## ${c.name} (${c.id})`];
  if (c.email) lines.push(`- **Email**: ${c.email}`);
  if (c.currency?.code) lines.push(`- **Currency**: ${c.currency.code}`);
  if (c.address?.city) {
    const loc = [c.address.city, c.address.country?.code].filter(Boolean).join(", ");
    lines.push(`- **Location**: ${loc}`);
  }
  lines.push(`- **Created**: ${c.createdAt?.slice(0, 10) ?? "unknown"}`);
  lines.push("");
  return lines;
}

export function registerCustomerTools(server: McpServer, client: WaveClient): void {
  // ── wave_list_customers ───────────────────────────────────────────────────

  server.registerTool(
    "wave_list_customers",
    {
      title: "List Wave Customers",
      description: `List customers for a Wave business with optional sorting and pagination.

Args:
  - businessId (string): Wave business ID
  - page (number): Page number (default: 1)
  - pageSize (number): Items per page, 1-100 (default: 20)
  - sort (string): Sort field — 'NAME' or 'CREATED_AT' (default: 'NAME')
  - sortDirection ('ASC' | 'DESC'): Sort direction (default: 'ASC')
  - response_format ('markdown' | 'json'): Output format (default: 'markdown')

Returns:
  Paginated list of customers with id, name, email, currency, and address.`,
      inputSchema: z.object({
        businessId: z.string().describe("Wave business ID"),
        page: z.number().int().min(1).default(1).describe("Page number"),
        pageSize: z.number().int().min(1).max(MAX_PAGE_SIZE).default(DEFAULT_PAGE_SIZE).describe("Items per page"),
        sort: z.enum(["NAME", "CREATED_AT"]).default("NAME").describe("Sort field"),
        sortDirection: z.enum(["ASC", "DESC"]).default("ASC").describe("Sort direction"),
        response_format: z.enum(["markdown", "json"]).default("markdown").describe("Output format"),
      }),
      annotations: { readOnlyHint: true, destructiveHint: false, idempotentHint: true, openWorldHint: true },
    },
    async ({ businessId, page, pageSize, sort, sortDirection, response_format }) => {
      try {
        const data = await client.query<CustomersData>(`
          query($businessId: ID!, $page: Int!, $pageSize: Int!, $sort: CustomerSort!, $sortDirection: SortDirection!) {
            business(id: $businessId) {
              customers(page: $page, pageSize: $pageSize, sort: $sort, sortDirection: $sortDirection) {
                pageInfo { currentPage totalPages totalCount }
                edges { node { ${CUSTOMER_FIELDS} } }
              }
            }
          }
        `, { businessId, page, pageSize, sort, sortDirection });

        const { pageInfo, edges } = data.business.customers;
        const customers = edges.map((e) => e.node);

        if (!customers.length) {
          return { content: [{ type: "text", text: "No customers found." }] };
        }

        const result = {
          total: pageInfo.totalCount,
          count: customers.length,
          page: pageInfo.currentPage,
          totalPages: pageInfo.totalPages,
          has_more: pageInfo.currentPage < pageInfo.totalPages,
          next_page: pageInfo.currentPage < pageInfo.totalPages ? pageInfo.currentPage + 1 : undefined,
          customers,
        };

        let text: string;
        if (response_format === "json") {
          text = JSON.stringify(result, null, 2);
        } else {
          const lines = [
            `# Customers (${pageInfo.totalCount} total, page ${pageInfo.currentPage}/${pageInfo.totalPages})`,
            "",
          ];
          for (const c of customers) lines.push(...formatCustomerMarkdown(c));
          text = lines.join("\n");
        }

        return {
          content: [{ type: "text", text: WaveClient.truncate(text) }],
          structuredContent: result,
        };
      } catch (error) {
        return { content: [{ type: "text", text: `Error: ${error instanceof Error ? error.message : String(error)}` }] };
      }
    }
  );

  // ── wave_get_customer ─────────────────────────────────────────────────────

  server.registerTool(
    "wave_get_customer",
    {
      title: "Get Wave Customer",
      description: `Get details for a specific customer by ID.

Args:
  - businessId (string): Wave business ID
  - customerId (string): Customer ID
  - response_format ('markdown' | 'json'): Output format (default: 'markdown')

Returns:
  Full customer details including contact info and address.`,
      inputSchema: z.object({
        businessId: z.string().describe("Wave business ID"),
        customerId: z.string().describe("Customer ID"),
        response_format: z.enum(["markdown", "json"]).default("markdown").describe("Output format"),
      }),
      annotations: { readOnlyHint: true, destructiveHint: false, idempotentHint: true, openWorldHint: true },
    },
    async ({ businessId, customerId, response_format }) => {
      try {
        const data = await client.query<CustomerData>(`
          query($businessId: ID!, $customerId: ID!) {
            business(id: $businessId) {
              customer(id: $customerId) { ${CUSTOMER_FIELDS} }
            }
          }
        `, { businessId, customerId });

        const c = data.business.customer;
        if (!c) return { content: [{ type: "text", text: `No customer found with ID: ${customerId}` }] };

        let text: string;
        if (response_format === "json") {
          text = JSON.stringify(c, null, 2);
        } else {
          text = formatCustomerMarkdown(c).join("\n");
        }

        return { content: [{ type: "text", text }], structuredContent: c };
      } catch (error) {
        return { content: [{ type: "text", text: `Error: ${error instanceof Error ? error.message : String(error)}` }] };
      }
    }
  );

  // ── wave_create_customer ──────────────────────────────────────────────────

  server.registerTool(
    "wave_create_customer",
    {
      title: "Create Wave Customer",
      description: `Create a new customer in a Wave business.

Args:
  - businessId (string): Wave business ID
  - name (string): Customer display name (required)
  - firstName (string): First name (optional)
  - lastName (string): Last name (optional)
  - email (string): Email address (optional)
  - currencyCode (string): ISO 4217 currency code, e.g. 'USD' (optional)
  - addressLine1 (string): Street address (optional)
  - city (string): City (optional)
  - postalCode (string): Postal/ZIP code (optional)
  - countryCode (string): ISO 3166-1 alpha-2 country code, e.g. 'US' (optional)
  - response_format ('markdown' | 'json'): Output format (default: 'markdown')

Returns:
  Created customer details or validation errors.`,
      inputSchema: z.object({
        businessId: z.string().describe("Wave business ID"),
        name: z.string().min(1).describe("Customer display name"),
        firstName: z.string().optional().describe("First name"),
        lastName: z.string().optional().describe("Last name"),
        email: z.string().email().optional().describe("Email address"),
        currencyCode: z.string().length(3).optional().describe("ISO 4217 currency code (e.g. 'USD')"),
        addressLine1: z.string().optional().describe("Street address"),
        city: z.string().optional().describe("City"),
        postalCode: z.string().optional().describe("Postal/ZIP code"),
        countryCode: z.string().length(2).optional().describe("ISO 3166-1 alpha-2 country code (e.g. 'US')"),
        response_format: z.enum(["markdown", "json"]).default("markdown").describe("Output format"),
      }),
      annotations: { readOnlyHint: false, destructiveHint: false, idempotentHint: false, openWorldHint: true },
    },
    async ({ businessId, name, firstName, lastName, email, currencyCode, addressLine1, city, postalCode, countryCode, response_format }) => {
      try {
        const input: Record<string, unknown> = { businessId, name };
        if (firstName) input.firstName = firstName;
        if (lastName) input.lastName = lastName;
        if (email) input.email = email;
        if (currencyCode) input.currency = currencyCode;
        if (addressLine1 || city || postalCode || countryCode) {
          const address: Record<string, unknown> = {};
          if (addressLine1) address.addressLine1 = addressLine1;
          if (city) address.city = city;
          if (postalCode) address.postalCode = postalCode;
          if (countryCode) address.countryCode = countryCode;
          input.address = address;
        }

        const data = await client.query<CustomerCreateData>(`
          mutation($input: CustomerCreateInput!) {
            customerCreate(input: $input) {
              didSucceed
              inputErrors { code message path }
              customer { ${CUSTOMER_FIELDS} }
            }
          }
        `, { input });

        const result = data.customerCreate;

        if (!result.didSucceed) {
          const errs = result.inputErrors.map((e) => `  - ${e.path?.join(".") ?? "field"}: ${e.message}`).join("\n");
          return { content: [{ type: "text", text: `Failed to create customer:\n${errs}` }] };
        }

        let text: string;
        if (response_format === "json") {
          text = JSON.stringify(result.customer, null, 2);
        } else {
          text = `Customer created successfully!\n\n${formatCustomerMarkdown(result.customer!).join("\n")}`;
        }

        return { content: [{ type: "text", text }], structuredContent: result.customer };
      } catch (error) {
        return { content: [{ type: "text", text: `Error: ${error instanceof Error ? error.message : String(error)}` }] };
      }
    }
  );

  // ── wave_update_customer ──────────────────────────────────────────────────

  server.registerTool(
    "wave_update_customer",
    {
      title: "Update Wave Customer",
      description: `Update an existing customer's details. Only provide fields you want to change.

Args:
  - businessId (string): Wave business ID
  - customerId (string): Customer ID to update
  - name (string): New display name (optional)
  - firstName (string): New first name (optional)
  - lastName (string): New last name (optional)
  - email (string): New email address (optional)
  - response_format ('markdown' | 'json'): Output format (default: 'markdown')

Returns:
  Updated customer details or validation errors.`,
      inputSchema: z.object({
        businessId: z.string().describe("Wave business ID"),
        customerId: z.string().describe("Customer ID to update"),
        name: z.string().min(1).optional().describe("New display name"),
        firstName: z.string().optional().describe("New first name"),
        lastName: z.string().optional().describe("New last name"),
        email: z.string().email().optional().describe("New email address"),
        response_format: z.enum(["markdown", "json"]).default("markdown").describe("Output format"),
      }),
      annotations: { readOnlyHint: false, destructiveHint: false, idempotentHint: true, openWorldHint: true },
    },
    async ({ businessId, customerId, name, firstName, lastName, email, response_format }) => {
      try {
        const input: Record<string, unknown> = { businessId, customerId };
        if (name) input.name = name;
        if (firstName !== undefined) input.firstName = firstName;
        if (lastName !== undefined) input.lastName = lastName;
        if (email !== undefined) input.email = email;

        const data = await client.query<CustomerPatchData>(`
          mutation($input: CustomerPatchInput!) {
            customerPatch(input: $input) {
              didSucceed
              inputErrors { code message path }
              customer { ${CUSTOMER_FIELDS} }
            }
          }
        `, { input });

        const result = data.customerPatch;
        if (!result.didSucceed) {
          const errs = result.inputErrors.map((e) => `  - ${e.path?.join(".") ?? "field"}: ${e.message}`).join("\n");
          return { content: [{ type: "text", text: `Failed to update customer:\n${errs}` }] };
        }

        let text: string;
        if (response_format === "json") {
          text = JSON.stringify(result.customer, null, 2);
        } else {
          text = `Customer updated successfully!\n\n${formatCustomerMarkdown(result.customer!).join("\n")}`;
        }

        return { content: [{ type: "text", text }], structuredContent: result.customer };
      } catch (error) {
        return { content: [{ type: "text", text: `Error: ${error instanceof Error ? error.message : String(error)}` }] };
      }
    }
  );

  // ── wave_delete_customer ──────────────────────────────────────────────────

  server.registerTool(
    "wave_delete_customer",
    {
      title: "Delete Wave Customer",
      description: `Permanently delete a customer from a Wave business.

⚠️ This action is irreversible. Customers with existing invoices may not be deletable.

Args:
  - businessId (string): Wave business ID
  - customerId (string): Customer ID to delete

Returns:
  Success confirmation or error details.`,
      inputSchema: z.object({
        businessId: z.string().describe("Wave business ID"),
        customerId: z.string().describe("Customer ID to delete"),
      }),
      annotations: { readOnlyHint: false, destructiveHint: true, idempotentHint: false, openWorldHint: true },
    },
    async ({ businessId, customerId }) => {
      try {
        const data = await client.query<CustomerDeleteData>(`
          mutation($input: CustomerDeleteInput!) {
            customerDelete(input: $input) {
              didSucceed
              inputErrors { code message path }
            }
          }
        `, { input: { businessId, customerId } });

        const result = data.customerDelete;
        if (!result.didSucceed) {
          const errs = result.inputErrors.map((e) => `  - ${e.message}`).join("\n");
          return { content: [{ type: "text", text: `Failed to delete customer:\n${errs}` }] };
        }

        return { content: [{ type: "text", text: `Customer ${customerId} deleted successfully.` }] };
      } catch (error) {
        return { content: [{ type: "text", text: `Error: ${error instanceof Error ? error.message : String(error)}` }] };
      }
    }
  );
}