import { type McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import fs from "node:fs";
import path from "node:path";
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",
        ),
        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",
        ),
        searchScope: z.enum(["all", "subject", "body", "from"]).default("all")
          .describe("Where to search"),
      }),
    },
    async ({ query, folderId, limit, offset, searchScope }) => {
      try {
        const client = getClient();

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

        limit = Math.max(1, Math.min(limit, 50));
        offset = Math.max(0, offset);

        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 targetFolder = folderId || "msgfolderroot";
        const traversal = folderId ? "Shallow" : "Deep";

        const items = await client.findItems(targetFolder, {
          limit,
          offset,
          restriction,
          traversal,
        });
        const results = formatSearchResults(items, client);

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

  server.registerTool(
    "mark_email_read",
    {
      description: "Mark one or more emails as read or unread",
      inputSchema: z.object({
        itemIds: z.array(z.string()).describe(
          "List of Exchange ItemIds to update",
        ),
        isRead: z.boolean().default(true).describe(
          "True to mark as read, False to mark as unread",
        ),
      }),
    },
    async ({ itemIds, isRead }) => {
      try {
        const client = new EwsClient(loadConfig());
        const responses = await client.updateItems(itemIds, [
          { fieldUri: "message:IsRead", value: isRead },
        ]);

        const errors = responses
          .filter((r: any) => r.ResponseClass === "Error")
          .map((r: any) => r.MessageText ?? "Unknown error");

        if (errors.length) {
          return {
            content: [{
              type: "text" as const,
              text: JSON.stringify({ error: errors.join("; ") }),
            }],
          };
        }

        const status = isRead ? "read" : "unread";
        return {
          content: [{
            type: "text" as const,
            text: JSON.stringify({
              success: true,
              message: `Marked ${itemIds.length} email(s) as ${status}.`,
            }),
          }],
        };
      } catch (error: any) {
        return {
          content: [{
            type: "text" as const,
            text: JSON.stringify({ error: error.message ?? String(error) }),
          }],
        };
      }
    },
  );

  server.registerTool(
    "download_attachments",
    {
      description: "Download all file attachments from an email to disk",
      inputSchema: z.object({
        itemId: z.string().describe("The Exchange ItemId of the email"),
        targetFolder: z.string().default("/tmp/attachments").describe(
          "Local directory to save files (default /tmp/attachments)",
        ),
      }),
    },
    async ({ itemId, targetFolder }) => {
      try {
        const client = new EwsClient(loadConfig());
        const item = await client.getItem(itemId);
        const email = client.extractEmailDetails(item);
        const attachments = email.attachments ?? [];

        const fileAttachments = attachments.filter(
          (a: any) => a.attachmentId && !a.isInline,
        );

        if (!fileAttachments.length) {
          return {
            content: [{
              type: "text" as const,
              text: JSON.stringify({
                success: true,
                downloaded: [],
                count: 0,
                message: "No downloadable file attachments.",
              }),
            }],
          };
        }

        fs.mkdirSync(targetFolder, { recursive: true });

        const downloaded = [];
        const errors = [];
        const usedNames = new Set<string>();

        for (const att of fileAttachments) {
          try {
            const result = await client.getAttachment(att.attachmentId);
            let filename = path.basename(result.name);
            if (!filename) filename = att.name || "attachment";

            const baseName = filename;
            const dotIdx = baseName.lastIndexOf(".");
            const namePart = dotIdx > 0 ? baseName.slice(0, dotIdx) : baseName;
            const extPart = dotIdx > 0 ? baseName.slice(dotIdx) : "";

            let counter = 1;
            let finalName = filename;
            while (usedNames.has(finalName.toLowerCase())) {
              finalName = extPart
                ? `${namePart}_${counter}${extPart}`
                : `${namePart}_${counter}`;
              counter++;
            }
            usedNames.add(finalName.toLowerCase());

            const filepath = path.join(targetFolder, finalName);
            fs.writeFileSync(filepath, result.content);

            downloaded.push({
              name: finalName,
              path: filepath,
              size: result.content.length,
              contentType: result.contentType,
            });
          } catch (e: any) {
            errors.push({
              name: att.name || "unknown",
              error: e.message ?? String(e),
            });
          }
        }

        return {
          content: [{
            type: "text" as const,
            text: JSON.stringify({
              success: errors.length === 0,
              downloaded,
              count: downloaded.length,
              ...(errors.length ? { errors } : {}),
            }),
          }],
        };
      } catch (error: any) {
        return {
          content: [{
            type: "text" as const,
            text: JSON.stringify({ error: error.message ?? String(error) }),
          }],
        };
      }
    },
  );
}

function formatSearchResults(
  items: any[],
  client: EwsClient,
): any[] {
  const results: any[] = [];
  for (const item of items) {
    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;
}