import { McpContext, Resolver, Tool } from '@nestjs-mcp/server';
import { z } from 'zod';
import { TaskStreamApi } from '../api/taskstream-api';
import { issueRef, limit, projectRef } from './params';
import { issueLine } from './summaries';
import { toolResult } from './tool-result';

const READ = { readOnlyHint: true, openWorldHint: false } as const;
const WRITE = {
  readOnlyHint: false,
  destructiveHint: false,
  openWorldHint: false,
} as const;
const REMOVE = {
  readOnlyHint: false,
  destructiveHint: true,
  openWorldHint: false,
} as const;

const PRIORITY = z.enum(['LOWEST', 'LOW', 'MEDIUM', 'HIGH', 'CRITICAL']);
const CATEGORY = z.enum(['TODO', 'IN_PROGRESS', 'QA', 'DONE', 'CANCELLED']);
const LINK_TYPE = z.enum([
  'BLOCKS',
  'DEPENDS_ON',
  'TESTS',
  'DUPLICATES',
  'RELATES_TO',
]);

const ids = (what: string) =>
  z
    .array(z.string())
    .optional()
    .describe(`${what} ids of the project's settings (see get_project)`);

const issueFields = {
  description: z.string().max(50000).optional(),
  area: z.string().optional().describe('Area id (see get_project)'),
  priority: PRIORITY.optional(),
  labels: z.array(z.string().max(40)).max(20).optional(),
  figmaUrl: z.string().url().optional().describe('Figma frame (https)'),
  storyPoints: z.number().int().min(0).max(100).optional(),
  startDate: z
    .string()
    .optional()
    .describe('ISO date when work should start (roadmap)'),
  dueDate: z.string().optional().describe('ISO date, e.g. 2026-11-14'),
};

type IssueFields = {
  description?: string;
  area?: string;
  priority?: z.infer<typeof PRIORITY>;
  labels?: string[];
  figmaUrl?: string;
  storyPoints?: number;
  startDate?: string;
  dueDate?: string;
};

@Resolver()
export class IssuesResolver {
  constructor(private readonly api: TaskStreamApi) {}

  /* ---- Reading ---- */

  @Tool({
    name: 'my_issues',
    description:
      "Tickets across all the user's projects: assigned to them (default) or anyone's, filtered by status category (e.g. QA to see what waits for testing).",
    paramsSchema: z.object({
      assignedToMe: z.boolean().default(true),
      categories: z
        .array(CATEGORY)
        .optional()
        .describe('Default: open ones (TODO, IN_PROGRESS, QA)'),
      limit: limit(200, 50),
    }),
    annotations: READ,
  })
  mine(
    params: {
      assignedToMe: boolean;
      categories?: z.infer<typeof CATEGORY>[];
      limit: number;
    },
    ctx: McpContext,
  ) {
    return toolResult(async () => {
      const page = await this.api.data(
        this.api.as(ctx).GET('/api/me/issues', {
          params: {
            query: {
              assignedToMe: params.assignedToMe,
              category: params.categories ?? ['TODO', 'IN_PROGRESS', 'QA'],
              limit: params.limit,
            },
          },
        }),
      );
      return { total: page.total, items: page.items.map(issueLine) };
    });
  }

  @Tool({
    name: 'search_issues',
    description:
      'Search the tickets of a project by text (key, title, description) and filters. The backlog: noSprint with sort RANK.',
    paramsSchema: z.object({
      project: projectRef,
      search: z.string().max(200).optional(),
      statuses: ids('Status'),
      categories: z.array(CATEGORY).optional(),
      types: ids('Ticket type'),
      areas: ids('Area'),
      priorities: z.array(PRIORITY).optional(),
      assigneeId: z.string().optional().describe('User id'),
      unassigned: z.boolean().optional(),
      releaseId: z.string().optional(),
      labels: z.array(z.string()).optional(),
      parent: z
        .string()
        .optional()
        .describe('Only the tickets hanging from this epic or ticket (key)'),
      sprintId: z.string().optional().describe('Only this sprint'),
      noSprint: z
        .boolean()
        .optional()
        .describe('Only tickets in no sprint (the backlog)'),
      dueFrom: z.string().optional().describe('Due on or after (ISO date)'),
      dueTo: z.string().optional().describe('Due on or before (ISO date)'),
      sort: z
        .enum(['RECENT', 'RANK'])
        .default('RECENT')
        .describe('RECENT: last updated first. RANK: backlog order'),
      limit: limit(200, 30),
      offset: z.number().int().min(0).default(0),
    }),
    annotations: READ,
  })
  search(
    params: {
      project: string;
      search?: string;
      statuses?: string[];
      categories?: z.infer<typeof CATEGORY>[];
      types?: string[];
      areas?: string[];
      priorities?: z.infer<typeof PRIORITY>[];
      assigneeId?: string;
      unassigned?: boolean;
      releaseId?: string;
      labels?: string[];
      parent?: string;
      sprintId?: string;
      noSprint?: boolean;
      dueFrom?: string;
      dueTo?: string;
      sort: 'RECENT' | 'RANK';
      limit: number;
      offset: number;
    },
    ctx: McpContext,
  ) {
    return toolResult(async () => {
      const page = await this.api.data(
        this.api.as(ctx).GET('/api/projects/{project}/issues', {
          params: {
            path: { project: params.project },
            query: {
              search: params.search,
              status: params.statuses,
              category: params.categories,
              type: params.types,
              area: params.areas,
              priority: params.priorities,
              assigneeId: params.assigneeId,
              unassigned: params.unassigned,
              releaseId: params.releaseId,
              label: params.labels,
              parent: params.parent,
              sprintId: params.sprintId,
              noSprint: params.noSprint,
              dueFrom: params.dueFrom,
              dueTo: params.dueTo,
              sort: params.sort,
              limit: params.limit,
              offset: params.offset,
            },
          },
        }),
      );
      return { total: page.total, items: page.items.map(issueLine) };
    });
  }

  @Tool({
    name: 'get_issue',
    description:
      'A ticket in full: description, parent, checklist (with item ids), links, commits and pull requests, followers, allowed next statuses, and optionally its comments and history.',
    paramsSchema: z.object({
      issue: issueRef,
      withComments: z.boolean().default(true),
      withHistory: z.boolean().default(false),
    }),
    annotations: READ,
  })
  getIssue(
    params: { issue: string; withComments: boolean; withHistory: boolean },
    ctx: McpContext,
  ) {
    return toolResult(async () => {
      const client = this.api.as(ctx);
      const path = { issue: params.issue };
      const issue = await this.api.data(
        client.GET('/api/issues/{issue}', { params: { path } }),
      );
      const comments = params.withComments
        ? (
            await this.api.data(
              client.GET('/api/issues/{issue}/comments', {
                params: { path, query: { limit: 100 } },
              }),
            )
          ).items.map((c) => ({
            id: c.id,
            replyTo: c.replyTo,
            author: c.deleted ? null : c.author.name,
            at: c.createdAt,
            body: c.deleted ? '(deleted; kept for its replies)' : c.body,
          }))
        : undefined;
      const history = params.withHistory
        ? (
            await this.api.data(
              client.GET('/api/issues/{issue}/history', {
                params: { path, query: { limit: 100 } },
              }),
            )
          ).map((a) => ({ at: a.occurredAt, summary: a.summary }))
        : undefined;
      return {
        ...issueLine(issue),
        description: issue.description,
        reporter: issue.reporter.name,
        figmaUrl: issue.figmaUrl,
        startDate: issue.startDate,
        allowedTransitions: issue.allowedTransitions,
        parent: issue.parent,
        checklist: issue.checklist,
        links: issue.links,
        devLinks: issue.devLinks.map((d) => ({
          kind: d.kind,
          repository: d.repository,
          ref: d.ref,
          title: d.title,
          state: d.state,
          url: d.url,
        })),
        watchers: issue.watchers.map((w) => w.name),
        attachments: issue.attachments.length,
        trashedAt: issue.trashedAt,
        createdAt: issue.createdAt,
        comments,
        history,
      };
    });
  }

  /* ---- Writing ---- */

  @Tool({
    name: 'create_issue',
    description:
      'Create a ticket. Type and area are ids of the project settings (see get_project); it starts in the first pending status.',
    paramsSchema: z.object({
      project: projectRef,
      type: z.string().describe('Ticket type id, e.g. BUG'),
      title: z.string().min(1).max(255),
      assigneeId: z.string().optional().describe('User id (a project member)'),
      releaseId: z.string().optional(),
      parent: z
        .string()
        .optional()
        .describe('Epic or ticket of the same project it breaks down (key)'),
      ...issueFields,
    }),
    annotations: WRITE,
  })
  create(
    params: IssueFields & {
      project: string;
      type: string;
      title: string;
      assigneeId?: string;
      releaseId?: string;
      parent?: string;
    },
    ctx: McpContext,
  ) {
    const { project, ...body } = params;
    return toolResult(() =>
      this.api.data(
        this.api.as(ctx).POST('/api/projects/{project}/issues', {
          params: { path: { project } },
          body,
        }),
      ),
    );
  }

  @Tool({
    name: 'update_issue',
    description: 'Change the title, description, type, area, priority, labels…',
    paramsSchema: z.object({
      issue: issueRef,
      title: z.string().min(1).max(255).optional(),
      type: z.string().optional().describe('Ticket type id'),
      ...issueFields,
    }),
    annotations: { ...WRITE, idempotentHint: true },
  })
  update(
    params: IssueFields & { issue: string; title?: string; type?: string },
    ctx: McpContext,
  ) {
    const { issue, ...body } = params;
    return toolResult(() =>
      this.api.data(
        this.api.as(ctx).PATCH('/api/issues/{issue}', {
          params: { path: { issue } },
          body,
        }),
      ),
    );
  }

  @Tool({
    name: 'change_issue_status',
    description:
      "Move a ticket to another status. It must be one of the ticket's allowedTransitions (see get_issue); some statuses need a reason.",
    paramsSchema: z.object({
      issue: issueRef,
      status: z.string().describe('Status id, e.g. IN_PROGRESS'),
      reason: z.string().max(5000).optional(),
    }),
    annotations: WRITE,
  })
  changeStatus(
    {
      issue,
      status,
      reason,
    }: { issue: string; status: string; reason?: string },
    ctx: McpContext,
  ) {
    return toolResult(() =>
      this.api.data(
        this.api.as(ctx).PUT('/api/issues/{issue}/status', {
          params: { path: { issue } },
          body: { status, reason },
        }),
      ),
    );
  }

  @Tool({
    name: 'assign_issue',
    description: 'Assign a ticket to a project member, or unassign it (null).',
    paramsSchema: z.object({
      issue: issueRef,
      assigneeId: z.string().nullable().describe('User id, or null'),
    }),
    annotations: { ...WRITE, idempotentHint: true },
  })
  assign(
    { issue, assigneeId }: { issue: string; assigneeId: string | null },
    ctx: McpContext,
  ) {
    return toolResult(() =>
      this.api.data(
        this.api.as(ctx).PUT('/api/issues/{issue}/assignee', {
          params: { path: { issue } },
          body: { assigneeId },
        }),
      ),
    );
  }

  @Tool({
    name: 'set_issue_release',
    description: 'Put a ticket in a planned release, or take it out (null).',
    paramsSchema: z.object({
      issue: issueRef,
      releaseId: z.string().nullable(),
    }),
    annotations: { ...WRITE, idempotentHint: true },
  })
  setRelease(
    { issue, releaseId }: { issue: string; releaseId: string | null },
    ctx: McpContext,
  ) {
    return toolResult(() =>
      this.api.data(
        this.api.as(ctx).PUT('/api/issues/{issue}/release', {
          params: { path: { issue } },
          body: { releaseId },
        }),
      ),
    );
  }

  @Tool({
    name: 'add_comment',
    description:
      'Comment on a ticket (decisions, explanations, steps), or answer a comment with replyTo (one level: answering a reply joins its thread).',
    paramsSchema: z.object({
      issue: issueRef,
      body: z.string().min(1).max(20000),
      replyTo: z
        .string()
        .optional()
        .describe('Id of the comment it answers (see get_issue)'),
    }),
    annotations: WRITE,
  })
  comment(
    { issue, body, replyTo }: { issue: string; body: string; replyTo?: string },
    ctx: McpContext,
  ) {
    return toolResult(() =>
      this.api.data(
        this.api.as(ctx).POST('/api/issues/{issue}/comments', {
          params: { path: { issue } },
          body: { body, replyTo },
        }),
      ),
    );
  }

  @Tool({
    name: 'link_issues',
    description:
      'Relate two tickets, e.g. WEB-3 DEPENDS_ON API-7 (they may be in different projects).',
    paramsSchema: z.object({
      issue: issueRef,
      type: LINK_TYPE,
      target: issueRef,
    }),
    annotations: WRITE,
  })
  link(
    params: { issue: string; type: z.infer<typeof LINK_TYPE>; target: string },
    ctx: McpContext,
  ) {
    return toolResult(() =>
      this.api.data(
        this.api.as(ctx).POST('/api/issues/{issue}/links', {
          params: { path: { issue: params.issue } },
          body: { type: params.type, targetIssue: params.target },
        }),
      ),
    );
  }

  @Tool({
    name: 'unlink_issues',
    description:
      'Remove a relation between two tickets (as link_issues made it).',
    paramsSchema: z.object({
      issue: issueRef,
      type: LINK_TYPE,
      target: issueRef,
    }),
    annotations: REMOVE,
  })
  unlink(
    params: { issue: string; type: z.infer<typeof LINK_TYPE>; target: string },
    ctx: McpContext,
  ) {
    return toolResult(() =>
      this.api.data(
        this.api.as(ctx).DELETE('/api/issues/{issue}/links/{type}/{target}', {
          params: { path: params },
        }),
      ),
    );
  }

  @Tool({
    name: 'watch_issue',
    description:
      'Follow a ticket (notifications of its changes and comments) or stop following it.',
    paramsSchema: z.object({
      issue: issueRef,
      follow: z.boolean().default(true),
    }),
    annotations: { ...WRITE, idempotentHint: true },
  })
  watch(
    { issue, follow }: { issue: string; follow: boolean },
    ctx: McpContext,
  ) {
    const client = this.api.as(ctx);
    const options = { params: { path: { issue } } };
    return toolResult(() =>
      this.api.data(
        follow
          ? client.PUT('/api/issues/{issue}/watch', options)
          : client.DELETE('/api/issues/{issue}/watch', options),
      ),
    );
  }

  @Tool({
    name: 'edit_comment',
    description:
      'Reword a comment (only its author). Comment ids come with get_issue.',
    paramsSchema: z.object({
      commentId: z.string().min(1),
      body: z.string().min(1).max(20000),
    }),
    annotations: { ...WRITE, idempotentHint: true },
  })
  editComment(
    { commentId, body }: { commentId: string; body: string },
    ctx: McpContext,
  ) {
    return toolResult(() =>
      this.api.data(
        this.api.as(ctx).PATCH('/api/comments/{commentId}', {
          params: { path: { commentId } },
          body: { body },
        }),
      ),
    );
  }

  @Tool({
    name: 'delete_comment',
    description: 'Delete a comment (its author or a project admin).',
    paramsSchema: z.object({ commentId: z.string().min(1) }),
    annotations: REMOVE,
  })
  deleteComment({ commentId }: { commentId: string }, ctx: McpContext) {
    return toolResult(() =>
      this.api.data(
        this.api.as(ctx).DELETE('/api/comments/{commentId}', {
          params: { path: { commentId } },
        }),
      ),
    );
  }

  /* ---- Checklist ---- */

  @Tool({
    name: 'add_checklist_item',
    description: "Add a step to a ticket's checklist.",
    paramsSchema: z.object({
      issue: issueRef,
      text: z.string().min(1).max(300),
    }),
    annotations: WRITE,
  })
  addChecklistItem(
    { issue, text }: { issue: string; text: string },
    ctx: McpContext,
  ) {
    return toolResult(() =>
      this.api.data(
        this.api.as(ctx).POST('/api/issues/{issue}/checklist', {
          params: { path: { issue } },
          body: { text },
        }),
      ),
    );
  }

  @Tool({
    name: 'update_checklist_item',
    description:
      'Tick, untick or reword a checklist step. Item ids come with get_issue.',
    paramsSchema: z.object({
      issue: issueRef,
      item: z.string().min(1).describe('Checklist item id'),
      done: z.boolean().optional(),
      text: z.string().min(1).max(300).optional(),
    }),
    annotations: { ...WRITE, idempotentHint: true },
  })
  updateChecklistItem(
    params: { issue: string; item: string; done?: boolean; text?: string },
    ctx: McpContext,
  ) {
    const { issue, item, ...body } = params;
    return toolResult(() =>
      this.api.data(
        this.api.as(ctx).PATCH('/api/issues/{issue}/checklist/{item}', {
          params: { path: { issue, item } },
          body,
        }),
      ),
    );
  }

  @Tool({
    name: 'remove_checklist_item',
    description: "Remove a step from a ticket's checklist.",
    paramsSchema: z.object({
      issue: issueRef,
      item: z.string().min(1).describe('Checklist item id'),
    }),
    annotations: REMOVE,
  })
  removeChecklistItem(
    { issue, item }: { issue: string; item: string },
    ctx: McpContext,
  ) {
    return toolResult(() =>
      this.api.data(
        this.api.as(ctx).DELETE('/api/issues/{issue}/checklist/{item}', {
          params: { path: { issue, item } },
        }),
      ),
    );
  }
}