import YAML from "yaml";

export function splitTicketDocMetaSection(content = "") {
  const src = String(content || "");
  const lines = src.split(/\r?\n/);
  const start = lines.findIndex(line => /^##\s+DocMeta\s*$/i.test(line.trim()));
  if (start === -1) {
    return { body: src, docmetaRaw: "", docmeta: null };
  }

  const body = lines.slice(0, start).join("\n").trimEnd();
  const docmetaSection = lines.slice(start).join("\n").trim();
  const fence = docmetaSection.match(/```(?:ya?ml)?\s*\n([\s\S]*?)\n```/i);
  const docmetaRaw = fence ? fence[1].trim() : "";
  let docmeta = null;
  if (docmetaRaw) {
    try {
      docmeta = YAML.parse(docmetaRaw) || null;
    } catch {
      docmeta = null;
    }
  }
  return { body, docmetaRaw, docmeta };
}

export function buildDocMetaFrontmatterSummary(docmeta = null) {
  if (!docmeta || typeof docmeta !== "object") return {};
  const errors = Array.isArray(docmeta.validation?.errors)
    ? docmeta.validation.errors.map(value => String(value)).filter(Boolean)
    : [];
  return Object.fromEntries(Object.entries({
    docmetaStatus: docmeta.output_status || undefined,
    docmetaTarget: docmeta.target_state || docmeta.targetState || undefined,
    docmetaValidation: docmeta.validation?.status || undefined,
    docmetaErrors: errors.length ? errors : undefined
  }).filter(([, value]) => value !== undefined && value !== ""));
}

export function clearDocMetaFrontmatterSummary(meta: Record<string, any> = {}) {
  const next = { ...meta };
  delete next.docmeta;
  delete next.docmetaStatus;
  delete next.docmetaTarget;
  delete next.docmetaValidation;
  delete next.docmetaErrors;
  return next;
}

export function appendTicketDocMetaSection(content = "", docmeta = null) {
  const body = splitTicketDocMetaSection(content).body.trimEnd();
  if (!docmeta || typeof docmeta !== "object") return `${body}\n`;
  const yamlStr = YAML.stringify(docmeta).trim();
  return `${body}\n\n## DocMeta\n\n\`\`\`yaml\n${yamlStr}\n\`\`\`\n`;
}

export function buildTransitionValidationDocMeta(input: Record<string, any> = {}) {
  const {
    ticketId = "",
    phase = 1,
    status = "open",
    currentState = `phase${phase || 1}`,
    targetState = "",
    requiredSlots = [],
    slotValues = {},
    slotSourceMap = {}
  } = input;
  const slots = Object.fromEntries(requiredSlots.map(slot => [slot, Boolean(slotValues[slot])]));
  const filteredSlotSourceMap = Object.fromEntries(
    requiredSlots.map(slot => [slot, slotSourceMap[slot] || { source: "unknown" }])
  );
  const errors = Object.entries(slots)
    .filter(([, passed]) => !passed)
    .map(([slot]) => slot);
  return {
    document_type: "ticket_validation",
    document_subtype: "ticket_workflow_transition_gate",
    contract_version: "documeta-0.1",
    ticket_id: ticketId,
    state: {
      name: currentState,
      phase,
      status: String(status || "open")
    },
    target_state: targetState,
    source_contract: {
      required_slots: requiredSlots,
      metadata_fields: ["ticket_id", "workspace_id", "phase", "status", "target_state", "source_path"]
    },
    slots,
    slot_source_map: filteredSlotSourceMap,
    validation: {
      status: errors.length === 0 ? "PASS" : "NEEDS_FIX",
      errors
    },
    output_status: errors.length === 0 ? "transition_allowed" : "transition_blocked",
    adapter_contracts: {
      cli: {
        action: targetState === "phase2" ? "ticket move" : "ticket workflow transition",
        stop_if_output_status: "transition_blocked"
      }
    }
  };
}