/**
 * Prompts used by the code-review graph in `graph/code-review.ts`.
 *
 * The graph runs a small ensemble of focused steps; each step gets a tightly
 * scoped user prompt while sharing one reviewer system prompt, so the model
 * keeps a consistent voice and rubric across nodes.
 */

export const CODE_REVIEW_SYSTEM_PROMPT = `You are a senior staff engineer performing a code review.

Operating principles:
- Be precise. Cite the file and (when possible) the symbol or hunk you are referring to.
- Prefer correctness > security > performance > readability > style.
- Do not invent code that is not in the diff. If something is unclear, say so explicitly.
- When suggesting a change, show the smallest reasonable patch (a few lines) rather than rewriting whole files.
- Severity levels: "blocker" (must fix before merge), "major" (should fix), "minor" (nice to fix), "nit" (style/preference).
- Never fabricate test results, runtime behavior, or external API contracts.`;

export type FileChangeInput = {
  path: string;
  status: "added" | "modified" | "deleted" | "renamed";
  oldPath?: string;
  /** Unified diff for this file, or full file contents for added files. */
  patch: string;
};

function fenceForPath(path: string): string {
  const ext = path.split(".").pop()?.toLowerCase() ?? "";
  switch (ext) {
    case "ts":
    case "tsx":
      return "ts";
    case "js":
    case "jsx":
      return "js";
    case "py":
      return "python";
    case "go":
      return "go";
    case "rs":
      return "rust";
    case "json":
      return "json";
    case "md":
      return "markdown";
    default:
      return "diff";
  }
}

export function buildSummarizeChangesPrompt(files: FileChangeInput[]): string {
  const fileList = files
    .map((f) => `- ${f.status.toUpperCase()} ${f.path}${f.oldPath ? ` (was ${f.oldPath})` : ""}`)
    .join("\n");

  const bodies = files
    .map(
      (f) =>
        `### ${f.path}\n\n\`\`\`${fenceForPath(f.path)}\n${f.patch.trim()}\n\`\`\``,
    )
    .join("\n\n");

  return `Summarize the intent of this change set in 2-4 sentences. Then list the most affected modules.

Files:
${fileList}

Diffs:
${bodies}

Respond with:
1) "Summary:" — what the change does and why (inferred).
2) "Affected modules:" — bullet list of high-level areas (e.g., "auth/session", "tasks/api").`;
}

export function buildAnalyzeFilePrompt(file: FileChangeInput, summary: string): string {
  return `Review the following file change against the change-set summary below. Identify concrete issues only — do not list praise or generic advice.

Change-set summary:
${summary}

File: ${file.path} (${file.status}${file.oldPath ? `, was ${file.oldPath}` : ""})

\`\`\`${fenceForPath(file.path)}
${file.patch.trim()}
\`\`\`

For each issue, choose exactly one category: "correctness", "security", "performance", "readability", "style", "test-coverage".
For each issue, choose exactly one severity: "blocker", "major", "minor", "nit".
If there are no issues, return an empty list.`;
}

export function buildComposeReviewPrompt(input: {
  summary: string;
  affectedModules: string[];
  prioritizedIssues: Array<{
    file: string;
    severity: string;
    category: string;
    title: string;
    detail: string;
    suggestion?: string;
  }>;
}): string {
  const issueLines = input.prioritizedIssues
    .map(
      (i, idx) =>
        `${idx + 1}. [${i.severity}/${i.category}] ${i.file} — ${i.title}\n   ${i.detail}${i.suggestion ? `\n   Suggested: ${i.suggestion}` : ""}`,
    )
    .join("\n\n");

  const modules = input.affectedModules.length
    ? input.affectedModules.map((m) => `- ${m}`).join("\n")
    : "- (none identified)";

  return `Compose the final review as Markdown. Audience: the PR author.

Required structure:
# Code Review

## Summary
${input.summary}

## Affected modules
${modules}

## Findings
(For each finding below, render as a Markdown subsection with severity/category badges.
Group findings by severity in this order: blocker, major, minor, nit. Skip groups that are empty.)

Findings to render:
${issueLines || "(none)"}

## Verdict
End with one of: "Approve", "Approve with comments", "Request changes", or "Block".
Pick the strictest verdict justified by the findings (any blocker => "Block"; any major => "Request changes").

Do not add any sections beyond those listed.`;
}