// Git helpers for branch validation and commit operations
import { execSync } from "child_process"

export function getCurrentBranch(cwd = process.cwd()): string {
  return execSync("git rev-parse --abbrev-ref HEAD", { cwd, encoding: "utf-8" }).trim()
}

export function isClean(cwd = process.cwd()): boolean {
  const status = execSync("git status --porcelain", { cwd, encoding: "utf-8" }).trim()
  return status === ""
}

export function commitFile(path: string, message: string, cwd = process.cwd()): void {
  execSync(`git add ${path}`, { cwd })
  execSync(`git commit -m ${JSON.stringify(message)}`, { cwd })
}

export function commitFileWithBody(path: string, header: string, body: string, cwd = process.cwd()): void {
  execSync(`git add ${path}`, { cwd })
  const msg = `${header}\n\n${body}`
  execSync(`git commit -m ${JSON.stringify(msg)}`, { cwd })
}

export function branchExists(branch: string, cwd = process.cwd()): boolean {
  try {
    execSync(`git rev-parse --verify ${branch}`, { cwd, stdio: "pipe" })
    return true
  } catch {
    return false
  }
}

// Parse the issue branch name into type and ID
export function parseIssueBranch(branch: string): { type: string; id: number } | null {
  const match = branch.match(/^(feature|bugfix|hotfix)\/(\d+)$/)
  if (!match) return null
  return { type: match[1], id: Number(match[2]) }
}

export interface GitCommit {
  hash: string
  subject: string
  body: string
}

// Get commits on current branch since it diverged from a base branch
export function getCommitsSinceDiverge(base = "develop", cwd = process.cwd()): GitCommit[] {
  return parseGitLog(`${base}..HEAD`, cwd)
}

// Get commits from a ref spec (e.g. HEAD~3..HEAD)
export function getCommitsFromRef(refSpec: string, cwd = process.cwd()): GitCommit[] {
  return parseGitLog(refSpec, cwd)
}

// Get all commits on a branch
export function getAllCommits(branch: string, cwd = process.cwd()): GitCommit[] {
  return parseGitLog(branch, cwd)
}

function parseGitLog(range: string, cwd: string): GitCommit[] {
  const SEP = "---COMMIT-SEP---"
  const format = `%H%n%s%n%b%n${SEP}`
  let output: string
  try {
    output = execSync(
      `git log ${range} --format=${JSON.stringify(format)}`,
      { cwd, encoding: "utf-8" }
    )
  } catch {
    return []
  }

  const commits: GitCommit[] = []
  const entries = output.split(SEP).filter(e => e.trim())

  for (const entry of entries) {
    const lines = entry.trim().split("\n")
    if (lines.length < 2) continue
    commits.push({
      hash: lines[0],
      subject: lines[1],
      body: lines.slice(2).join("\n").trim(),
    })
  }

  return commits
}

// Check if a commit subject is a todo transition
export function parseTodoTransition(subject: string): { issueId: number; status: string } | null {
  const match = subject.match(/^todo\((\d+)\):\s*(\S+)/)
  if (!match) return null
  return { issueId: Number(match[1]), status: match[2] }
}