import { type McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { z } from "zod/v4";
import { EwsClient, loadConfig } from "../ews_client.ts";

function getClient(): EwsClient {
  return new EwsClient(loadConfig());
}

export function registerEmailTools(server: McpServer): void {
  server.registerTool(
    "get_emails",
    {
      description: "Get emails from a mailbox folder",
      inputSchema: z.object({
        folder: z.string().default("Inbox").describe(
          "Folder name (Inbox, Sent, Drafts, Deleted, Junk, or custom)",
        ),
        limit: z.number().default(10).describe(
          "Maximum number of emails to return (default 10, max 50)",
        ),
        offset: z.number().default(0).describe(
          "Number of emails to skip for pagination",
        ),
        includeBody: z.boolean().default(false).describe(
          "If True, fetch full body for each email (slower)",
        ),
        unreadOnly: z.boolean().default(false).describe(
          "If True, only return unread emails",
        ),
        idsOnly: z.boolean().default(false).describe(
          "If True, return only item IDs and dates (max limit 500)",
        ),
      }),
    },
    async ({ folder, limit, offset, includeBody, unreadOnly, idsOnly }) => {
      try {
        const client = getClient();
        const maxLimit = idsOnly ? 500 : 50;
        if (limit > maxLimit) limit = maxLimit;

        const folderId = await client.getFolderId(folder);
        const baseShape = idsOnly ? "IdOnly" : "AllProperties";

        let restriction = "";
        if (unreadOnly) {
          restriction = `\
      <m:Restriction>
        <t:IsEqualTo>
          <t:FieldURI FieldURI="message:IsRead"/>
          <t:FieldURIOrConstant>
            <t:Constant Value="false"/>
          </t:FieldURIOrConstant>
        </t:IsEqualTo>
      </m:Restriction>`;
        }

        const items = await client.findItems(folderId, {
          limit,
          offset,
          baseShape,
          restriction,
        });

        if (idsOnly) {
          const result = items.map((item: any) => ({
            itemId: item.ItemId?.["@_Id"] ?? "",
            date: item.DateTimeReceived ?? "",
            subject: item.Subject ?? "",
          }));
          return {
            content: [{
              type: "text" as const,
              text: JSON.stringify({ itemIds: result, count: result.length }),
            }],
          };
        }

        const emails = [];
        for (const item of items) {
          const email = client.extractEmailSummary(item);

          if (includeBody && email.itemId) {
            const details = client.extractEmailDetails(item);
            email.to = details.to;
            email.cc = details.cc;
            email.body = details.body;
            email.hasLinks = details.hasLinks;
          }

          emails.push(email);
        }

        return {
          content: [{
            type: "text" as const,
            text: JSON.stringify({ emails, count: emails.length }),
          }],
        };
      } catch (error: any) {
        return {
          content: [{
            type: "text" as const,
            text: JSON.stringify({ error: error.message ?? String(error) }),
          }],
        };
      }
    },
  );

  server.registerTool(
    "get_email",
    {
      description: "Get a single email with full body and details",
      inputSchema: z.object({
        itemId: z.string().describe(
          "The Exchange ItemId of the email to retrieve",
        ),
      }),
    },
    async ({ itemId }) => {
      try {
        const client = getClient();
        const item = await client.getItem(itemId);
        const email = client.extractEmailDetails(item);

        return {
          content: [{ type: "text" as const, text: JSON.stringify(email) }],
        };
      } catch (error: any) {
        return {
          content: [{
            type: "text" as const,
            text: JSON.stringify({ error: error.message ?? String(error) }),
          }],
        };
      }
    },
  );

  server.registerTool(
    "search_emails",
    {
      description: "Search emails by text across one or all folders",
      inputSchema: z.object({
        query: z.string().describe("The text to search for"),
        folderId: z.string().optional().describe(
          "Optional folder ID to limit the search. When omitted, searches all mail folders",
        ),
        maxResults: z.number().default(20).describe(
          "Maximum number of results (default 20, max 100)",
        ),
        searchScope: z.enum(["all", "subject", "body", "from"]).default("all")
          .describe("Where to search"),
      }),
    },
    async ({ query, folderId, maxResults, searchScope }) => {
      try {
        const client = getClient();

        if (!query.trim()) {
          return {
            content: [{
              type: "text" as const,
              text: JSON.stringify({
                error: "query must not be empty",
                results: [],
              }),
            }],
          };
        }

        maxResults = Math.max(1, Math.min(maxResults, 100));

        const fieldUriMap: Record<string, string> = {
          subject: "item:Subject",
          body: "item:Body",
          from: "message:From",
        };

        function containsExpression(fieldUri: string, value: string): string {
          return `\
        <t:Contains ContainmentMode="Substring" ContainmentComparison="IgnoreCase">
          <t:FieldURI FieldURI="${fieldUri}"/>
          <t:Constant Value="${
            value.replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(
              />/g,
              "&gt;",
            ).replace(/"/g, "&quot;")
          }"/>
        </t:Contains>`;
        }

        let restriction: string;
        if (searchScope === "all") {
          restriction = `\
      <m:Restriction>
        <t:Or>
          ${containsExpression("item:Subject", query)}
          ${containsExpression("item:Body", query)}
        </t:Or>
      </m:Restriction>`;
        } else {
          const fieldUri = fieldUriMap[searchScope];
          if (!fieldUri) {
            return {
              content: [{
                type: "text" as const,
                text: JSON.stringify({
                  error: `unsupported search_scope: ${searchScope}`,
                  results: [],
                }),
              }],
            };
          }
          restriction = `\
      <m:Restriction>
        ${containsExpression(fieldUri, query)}
      </m:Restriction>`;
        }

        const traversal = folderId ? "Shallow" : "Deep";

        if (folderId) {
          const items = await client.findItems(folderId, {
            limit: maxResults,
            restriction,
            traversal,
          });
          const results = formatSearchResults(items, client, maxResults);

          return {
            content: [{
              type: "text" as const,
              text: JSON.stringify({
                query,
                searchScope,
                folderId,
                totalResults: results.length,
                results,
              }),
            }],
          };
        } else {
          const folders = await client.findFolders("msgfolderroot", true);
          const allResults = [];

          for (const f of folders) {
            if (allResults.length >= maxResults) break;
            const remaining = maxResults - allResults.length;
            const items = await client.findItems(f.id, {
              limit: remaining,
              restriction,
              traversal: "Shallow",
            });
            const formatted = formatSearchResults(items, client, remaining);

            for (const r of formatted) {
              r.folderId = f.id;
              r.folderName = f.name;
              allResults.push(r);
              if (allResults.length >= maxResults) break;
            }
          }

          return {
            content: [{
              type: "text" as const,
              text: JSON.stringify({
                query,
                searchScope,
                folderId: "all",
                totalResults: allResults.length,
                results: allResults,
              }),
            }],
          };
        }
      } catch (error: any) {
        return {
          content: [{
            type: "text" as const,
            text: JSON.stringify({ error: error.message ?? String(error) }),
          }],
        };
      }
    },
  );
}

function formatSearchResults(
  items: any[],
  client: EwsClient,
  maxResults: number,
): any[] {
  const results: any[] = [];
  for (const item of items) {
    if (results.length >= maxResults) break;
    const summary = client.extractEmailSummary(item);

    const bodyHtml = item.Body?.Value ?? item.Body?.["#text"] ?? "";
    const bodyType = item.Body?.["@_BodyType"] ?? "HTML";
    let bodyPreview = "";
    if (bodyType === "HTML" && bodyHtml) {
      bodyPreview = bodyHtml.replace(/<[^>]+>/g, " ").replace(/\s+/g, " ")
        .trim().slice(0, 200);
    } else {
      bodyPreview = bodyHtml.slice(0, 200);
    }

    summary.preview = bodyPreview;

    results.push(summary);
  }
  return results;
}