import { Type } from "typebox";
import { parseMarkdown } from "../markdown/parse.js";
import { readSectionByPathSlug } from "../markdown/sections.js";
import type { SectionRead } from "../markdown/types.js";
import { readMarkdownText } from "./fs.js";

export const markdownReadParameters = Type.Object({
  path: Type.String({ description: "Markdown file path. A leading @ is ignored." }),
  sections: Type.Array(
    Type.Object({
      pathSlug: Type.String({ description: "Exact pathSlug returned by markdown_outline." }),
    }),
    { minItems: 1, description: "Sections to read by exact pathSlug." },
  ),
});

export interface MarkdownReadParams {
  path: string;
  sections: Array<{ pathSlug: string }>;
}

export function createMarkdownReadTool() {
  return {
    name: "markdown_read",
    label: "Markdown Read",
    description: "Read one or more complete Markdown sections by exact pathSlug. Each section includes descendant subsections and is hard-truncated only for output safety.",
    promptSnippet: "Read one or more Markdown sections by exact path slug.",
    promptGuidelines: [],
    parameters: markdownReadParameters,

    async execute(_toolCallId: string, params: MarkdownReadParams, _signal: AbortSignal | undefined, _onUpdate: unknown, ctx: { cwd: string }) {
      const file = await readMarkdownText(params.path, ctx.cwd);
      const parsed = parseMarkdown(file.text);
      const sections = removeSectionsContainedByAnotherSelection(
        params.sections.map((section) => readSectionByPathSlug(parsed, section.pathSlug)),
      );
      const output = {
        path: file.displayPath,
        totalLines: parsed.totalLines,
        sections,
      };

      return {
        content: [{ type: "text", text: sections.map((section) => section.content).join("\n\n") }],
        details: output,
      };
    },
  };
}

function removeSectionsContainedByAnotherSelection(sections: SectionRead[]): SectionRead[] {
  return sections.filter((section, index) => {
    return !sections.some((otherSection, otherIndex) => {
      if (otherIndex === index) return false;

      const sameSection =
        otherSection.heading.startLine === section.heading.startLine &&
        otherSection.heading.endLine === section.heading.endLine;
      if (sameSection) return otherIndex < index;

      return otherSection.heading.startLine <= section.heading.startLine && otherSection.heading.endLine >= section.heading.endLine;
    });
  });
}