import { createHash } from "node:crypto";
import { buildBasePrompt, PROMPT_VERSION } from "./base-v1.js";
import {
  truncateBlocks,
  type BlockContent,
  type BlockMeta,
  type TruncationConfig,
} from "./truncate.js";

export { PROMPT_VERSION };
export type { BlockMeta };

export type PromptMode = "full" | "minimal";

export interface PromptContext {
  name: string;
  cwd: string;
  description?: string;
  customPrompt?: string;
  envNames?: string[];
  secretNames?: string[];
  cronJobs?: string[];
  officeName?: string;
  officeDescription?: string;
  skillsPrompt?: string;
  hierarchy?: { manager: string | null; peers: string[]; reports: string[] };
  mode?: PromptMode;
  truncationConfig?: Partial<TruncationConfig>;
}

export interface ComposedPrompt {
  text: string;
  version: string;
  hash: string;
  blocks: BlockMeta[];
}

function buildOfficeBlock(ctx: PromptContext): string {
  if (!ctx.officeName) return "";
  const desc = ctx.officeDescription ? ` ${ctx.officeDescription}` : "";
  return `\n\n## Office\nYou work at ${ctx.officeName}.${desc}`;
}

function buildRuntimeBlock(ctx: PromptContext): string {
  const lines: string[] = [];
  if (ctx.envNames?.length) {
    lines.push(
      `Available environment variables: ${[...ctx.envNames].sort().join(", ")}`,
    );
  }
  if (ctx.secretNames?.length) {
    lines.push(
      `Available secrets (names only): ${[...ctx.secretNames].sort().join(", ")}`,
    );
  }
  if (ctx.cronJobs?.length) {
    lines.push(`Active cron jobs: ${[...ctx.cronJobs].sort().join("; ")}`);
  }
  if (lines.length === 0) return "";
  return "\n\n## Runtime Context\n" + lines.join("\n");
}

function buildIdentityBlock(ctx: PromptContext): string {
  const desc = ctx.description ? ` — ${ctx.description}` : "";
  return (
    `\n\nYou are agent "${ctx.name}"${desc}.\n` +
    `Your workspace is ${ctx.cwd}. All file tools (read, write, edit, bash) operate in this directory.`
  );
}

function buildCustomBlock(customPrompt?: string): string {
  if (!customPrompt?.trim()) return "";
  return `\n\n## Custom Instructions\n${customPrompt.trim()}`;
}

function buildHierarchyBlock(ctx: PromptContext): string {
  if (!ctx.hierarchy) return "";
  const mgr = ctx.hierarchy.manager ?? "the user (office operator)";
  const peers =
    ctx.hierarchy.peers.length > 0 ? ctx.hierarchy.peers.join(", ") : "none";
  const reports =
    ctx.hierarchy.reports.length > 0
      ? ctx.hierarchy.reports.join(", ")
      : "none";
  return (
    `\n\n## Hierarchy\n` +
    `You report to: ${mgr}\n` +
    `Your peers: ${peers}\n` +
    `Your direct reports: ${reports}`
  );
}

function buildSkillsBlock(skillsPrompt?: string): string {
  if (!skillsPrompt?.trim()) return "";
  return "\n\n" + skillsPrompt.trim();
}

export function hashPrompt(text: string): string {
  return createHash("sha256").update(text).digest("hex").slice(0, 12);
}

/** Blocks included in minimal mode (safety always in base). */
const MINIMAL_BLOCKS = new Set(["base", "identity", "custom"]);

export function composeSystemPrompt(ctx: PromptContext): ComposedPrompt {
  const mode = ctx.mode ?? "full";
  const rawBlocks: BlockContent[] = [
    { name: "base", text: buildBasePrompt() },
    { name: "office", text: buildOfficeBlock(ctx) },
    { name: "hierarchy", text: buildHierarchyBlock(ctx) },
    { name: "runtime", text: buildRuntimeBlock(ctx) },
    { name: "identity", text: buildIdentityBlock(ctx) },
    { name: "custom", text: buildCustomBlock(ctx.customPrompt) },
    { name: "skills", text: buildSkillsBlock(ctx.skillsPrompt) },
  ].filter((b) => {
    if (b.text.length === 0) return false;
    if (mode === "minimal" && !MINIMAL_BLOCKS.has(b.name)) return false;
    return true;
  });

  const { blocks: truncated, meta } = truncateBlocks(
    rawBlocks,
    ctx.truncationConfig,
  );
  const text = truncated.map((b) => b.text).join("");
  return {
    text,
    version: PROMPT_VERSION,
    hash: hashPrompt(text),
    blocks: meta,
  };
}