import {
    type IssueSnapshot,
    type Marker,
    marker,
    parseMarker,
    protocolVersion,
    sha256,
} from "../../core/contracts.js";
import { parseAgentCommand } from "../../core/webhook.js";
import type { GiteaComment, GiteaIssue } from "./types.js";

export function createIssueSnapshot(
    issue: GiteaIssue,
    comments: GiteaComment[],
    botLogin: string,
): IssueSnapshot {
    const humanComments = comments
        .filter(
            (comment) =>
                comment.user.login.toLowerCase() !== botLogin.toLowerCase(),
        )
        .filter((comment) => !parseAgentCommand(comment.body))
        .map((comment) => ({
            id: comment.id,
            author: comment.user.login,
            createdAt: comment.created_at,
            body: comment.body,
        }));
    const canonical = JSON.stringify({
        v: protocolVersion,
        number: issue.number,
        state: issue.state,
        title: issue.title,
        body: issue.body,
        comments: humanComments.map(({ author, createdAt, body }) => ({
            author,
            createdAt,
            body,
        })),
    });
    return {
        digest: sha256(canonical),
        title: issue.title,
        body: issue.body,
        comments: humanComments,
    };
}

export function findAcceptedPlan(
    comments: GiteaComment[],
    botLogin: string,
    issueNumber: number,
):
    | {
          marker: Marker;
          markdown: string;
          comment: GiteaComment;
      }
    | undefined {
    const candidates = comments
        .filter(
            (comment) =>
                comment.user.login.toLowerCase() === botLogin.toLowerCase(),
        )
        .map((comment) => ({
            comment,
            found: parseMarker(comment.body, "plan"),
        }))
        .filter((value): value is { comment: GiteaComment; found: Marker } =>
            Boolean(value.found),
        )
        .filter(
            (value) =>
                value.found.issue === issueNumber &&
                value.found.status === "accepted",
        )
        .sort((a, b) =>
            b.comment.updated_at.localeCompare(a.comment.updated_at),
        );
    const selected = candidates[0];
    if (!selected) return undefined;
    const header = "## Accepted implementation plan\n\n";
    const start = selected.comment.body.indexOf(header);
    const end = selected.comment.body.lastIndexOf(
        "\n\n<!-- gitea-agent:plan-footer -->",
    );
    if (start < 0) return undefined;
    const markdown = selected.comment.body
        .slice(start + header.length, end < 0 ? undefined : end)
        .trim();
    if (
        !selected.found.planDigest ||
        sha256(markdown) !== selected.found.planDigest
    )
        return undefined;
    return { marker: selected.found, markdown, comment: selected.comment };
}

export function renderStatus(input: {
    marker: Marker;
    heading: string;
    detail: string;
}): string {
    return `${marker(input.marker)}\n## ${input.heading}\n\n${input.detail}`;
}