import type { NormalizedBlock } from "../types";

interface CommitInfo {
  hash?: string;
  message: string;
}

const COMMIT_MSG_RE = /git\s+commit[^\n]*?-m\s+(?:"((?:[^"\\]|\\.)*)"|'((?:[^'\\]|\\.)*)'|\$?'((?:[^'\\]|\\.)*)')/;
// Match short hash from git output: "[branch hash]" or "main hash" or 7-12 hex
const HASH_RE = /\b([0-9a-f]{7,12})\b/;

const firstLineOf = (text: string): string => {
  const line = text.split(/\\n|\n/)[0] ?? "";
  return line.trim();
};

const cleanMessage = (msg: string): string =>
  msg.replace(/\\"/g, '"').replace(/\\'/g, "'").trim();

/**
 * Extract git commits from bash tool calls (`git commit -m "..."`) and pair
 * with hash from the immediately following tool_result.
 */
export const extractCommits = (blocks: NormalizedBlock[]): CommitInfo[] => {
  const commits: CommitInfo[] = [];

  for (let i = 0; i < blocks.length; i++) {
    const b = blocks[i];
    if (b.kind !== "tool_call" || b.name !== "bash") continue;
    const cmd = typeof b.args.command === "string" ? b.args.command : "";
    if (!/\bgit\s+commit\b/.test(cmd)) continue;
    const m = cmd.match(COMMIT_MSG_RE);
    if (!m) continue;
    const message = firstLineOf(cleanMessage(m[1] ?? m[2] ?? m[3] ?? ""));
    if (!message) continue;

    let hash: string | undefined;
    // Look at next tool_result for hash
    for (let j = i + 1; j < Math.min(blocks.length, i + 3); j++) {
      const r = blocks[j];
      if (r.kind !== "tool_result") continue;
      // Common git commit output: `[branch <hash>] message` or `<branch> <hash>..<hash>`
      const bracket = r.text.match(/\[\S+\s+([0-9a-f]{7,12})\]/);
      if (bracket) { hash = bracket[1]; break; }
      const range = r.text.match(/\b([0-9a-f]{7,12})\.\.([0-9a-f]{7,12})\b/);
      if (range) { hash = range[2]; break; }
      const plain = r.text.match(HASH_RE);
      if (plain) { hash = plain[1]; break; }
    }

    // Dedup by message+hash
    const key = `${hash ?? ""}::${message}`;
    if (!commits.some((c) => `${c.hash ?? ""}::${c.message}` === key)) {
      commits.push({ hash, message });
    }
  }

  return commits;
};

export const formatCommits = (commits: CommitInfo[], limit = 8): string[] => {
  const lines: string[] = [];
  const items = commits.slice(-limit); // keep most recent
  for (const c of items) {
    const prefix = c.hash ? `${c.hash}: ` : "";
    lines.push(`${prefix}${c.message}`);
  }
  return lines;
};