import {
  CiMetadata,
  CommitType,
  CommitEscalation,
  ParsedCiCommit,
  parseCommitType,
  parseCommitScope,
} from "../types/commit-meta.js";

const CI_BLOCK_START = "---ci---";
const CI_BLOCK_END = "---/ci---";

export function extractCiBlock(message: string): string | null {
  const startIdx = message.indexOf(CI_BLOCK_START);
  if (startIdx < 0) return null;

  const endIdx = message.indexOf(CI_BLOCK_END, startIdx);
  if (endIdx < 0) return null;

  return message.slice(startIdx + CI_BLOCK_START.length, endIdx).trim();
}

export function parseCiBlock(yaml: string): CiMetadata | null {
  if (!yaml) return null;

  const result: Partial<CiMetadata> = {};

  const phaseMatch = yaml.match(/^phase:\s*(.+)$/m);
  if (phaseMatch) result.phase = parseInt(phaseMatch[1], 10) || 0;

  const milestoneMatch = yaml.match(/^milestone:\s*(.+)$/m);
  if (milestoneMatch) result.milestone = milestoneMatch[1].trim();

  const planMatch = yaml.match(/^plan:\s*(.+)$/m);
  if (planMatch) result.plan = planMatch[1].trim();

  const taskMatch = yaml.match(/^task:\s*(.+)$/m);
  if (taskMatch) result.task = taskMatch[1].trim();

  const statusMatch = yaml.match(/^status:\s*(.+)$/m);
  if (statusMatch) result.status = statusMatch[1].trim() as CiMetadata["status"];

  const projectMatch = yaml.match(/^project:\s*(.+)$/m);
  if (projectMatch) result.project = projectMatch[1].trim();

  result.decisions = parseDecisionsFromYaml(yaml);
  result.escalations = parseEscalationsFromYaml(yaml);
  result.requirements = parseRequirementsFromYaml(yaml);
  result.lessons = parseLessonsFromYaml(yaml);
  result.compound = parseCompoundFromYaml(yaml);

  if (result.phase !== undefined && result.milestone !== undefined && result.status !== undefined) {
    return result as CiMetadata;
  }

  return null;
}

function parseDecisionsFromYaml(yaml: string): CiMetadata["decisions"] {
  const decisions: NonNullable<CiMetadata["decisions"]> = [];
  const decisionRegex = /- id: (.+)\n\s+decision: (.+)\n\s+rationale: (.+)\n\s+confidence: (.+)\n\s+alternatives: \[([^\]]*)\]/g;
  let match;

  while ((match = decisionRegex.exec(yaml)) !== null) {
    decisions.push({
      id: match[1].trim(),
      decision: match[2].trim(),
      rationale: match[3].trim(),
      confidence: parseFloat(match[4].trim()),
      alternatives: match[5].trim().split(",").map((a: string) => a.trim()).filter(Boolean),
    });
  }

  return decisions.length > 0 ? decisions : undefined;
}

function parseEscalationsFromYaml(yaml: string): CiMetadata["escalations"] {
  const escalations: NonNullable<CiMetadata["escalations"]> = [];
  const escalationRegex = /- id: (.+)\n\s+type: (.+)\n\s+description: (.+)\n\s+resolution: (.+)/g;
  let match;

  while ((match = escalationRegex.exec(yaml)) !== null) {
    escalations.push({
      id: match[1].trim(),
      type: match[2].trim(),
      description: match[3].trim(),
      resolution: match[4].trim() as CommitEscalation["resolution"],
    });
  }

  return escalations.length > 0 ? escalations : undefined;
}

function parseRequirementsFromYaml(yaml: string): CiMetadata["requirements"] {
  const coveredMatch = yaml.match(/^\s+covered: \[([^\]]*)\]/m);
  const partialMatch = yaml.match(/^\s+partial: \[([^\]]*)\]/m);

  const covered = coveredMatch
    ? coveredMatch[1].split(",").map((s: string) => s.trim()).filter(Boolean)
    : [];
  const partial = partialMatch
    ? partialMatch[1].split(",").map((s: string) => s.trim()).filter(Boolean)
    : [];

  if (covered.length === 0 && partial.length === 0) return undefined;
  return { covered, partial };
}

function parseLessonsFromYaml(yaml: string): CiMetadata["lessons"] {
  const lessonRegex = /^  - (.+)$/gm;
  const lessons: string[] = [];
  let inLessonsSection = false;

  for (const line of yaml.split("\n")) {
    if (/^lessons:/.test(line.trim())) {
      inLessonsSection = true;
      continue;
    }
    if (inLessonsSection && /^  - .+/.test(line)) {
      lessons.push(line.replace(/^  - /, "").trim());
    } else if (inLessonsSection && !/^  - /.test(line) && !/^$/.test(line)) {
      inLessonsSection = false;
    }
  }

  return lessons.length > 0 ? lessons : undefined;
}

function parseCompoundFromYaml(yaml: string): CiMetadata["compound"] {
  const categoryMatch = yaml.match(/^\s+category: (.+)$/m);
  const problemMatch = yaml.match(/^\s+problem: (.+)$/m);
  const solutionMatch = yaml.match(/^\s+solution: (.+)$/m);

  if (!categoryMatch || !problemMatch || !solutionMatch) return undefined;

  return {
    category: categoryMatch[1].trim(),
    problem: problemMatch[1].trim(),
    solution: solutionMatch[1].trim(),
  };
}

export function parseCommitMessage(
  hash: string,
  message: string
): ParsedCiCommit {
  const firstLine = message.split("\n")[0] || "";
  const subjectMatch = firstLine.match(/^(\w+)(?:\(([^)]+)\))?: (.+)$/);

  let type: CommitType = "chore";
  let scope = "";
  let subject = firstLine;

  if (subjectMatch) {
    type = parseCommitType(subjectMatch[1]);
    scope = subjectMatch[2] || "";
    subject = subjectMatch[3] || firstLine;
  }

  const ciBlock = extractCiBlock(message);
  const ci = ciBlock ? parseCiBlock(ciBlock) : null;

  const bodyStart = message.indexOf("\n");
  let body = bodyStart >= 0 ? message.slice(bodyStart + 1).trim() : "";

  if (ciBlock) {
    const blockStart = message.indexOf(CI_BLOCK_START);
    const blockEnd = message.indexOf(CI_BLOCK_END) + CI_BLOCK_END.length;

    const before = message.slice(bodyStart + 1, blockStart).trim();
    const after = message.slice(blockEnd).trim();
    body = [before, after].filter(Boolean).join("\n\n");
  }

  return { hash, type, scope, subject, ci, body };
}