const fs = require("fs");
const { resolveData } = require("./paths");

const historyFile = () => resolveData("metrics", "history.jsonl");
const stateFile = () => resolveData("metrics", "summary.json");
let retention = { mode: "count", count: 500, age_value: 30, age_unit: "days" };
function getSummary() {
  try { return JSON.parse(fs.readFileSync(stateFile(), "utf8")); }
  catch { return { total_requests:0, successful:0, failed:0, refusals:0, gate_decisions:0, tool_decisions:0, tool_suggestions:0, tool_executions:0, tool_denials:0, confirmation_cancellations:0, timeout_count:0, runtime_crash_count:0, runtime_self_test_total:0, runtime_self_test_failed_total:0, runtime_start_attempt_total:0, runtime_start_failed_total:0, verified_downloads:0, failed_downloads:0, requests_by_role:{}, requests_by_scope:{}, requests_by_route:{}, gate_reason_codes:{}, tool_rejections_by_reason:{}, runtime_exit_code_counts:{}, stage_totals:{}, stage_samples:0, slow_requests:[], durations:[], queue_wait_total_ms:0 }; }
}
function record(entry) {
  maybeApplyRetention();
  const summary = getSummary();
  summary.requests_by_role ||= {};
  summary.requests_by_scope ||= {};
  summary.requests_by_route ||= {};
  if (entry.kind === "request") {
    summary.total_requests += 1;
    if (entry.status === "success") summary.successful += 1;
    if (entry.status === "failed") summary.failed += 1;
    if (entry.status === "refused") summary.refusals += 1;
    if (entry.role) summary.requests_by_role[entry.role] = (summary.requests_by_role[entry.role] || 0) + 1;
    if (entry.scope) summary.requests_by_scope[entry.scope] = (summary.requests_by_scope[entry.scope] || 0) + 1;
  }
  if (entry.kind === "gate_decision") {
    summary.gate_decisions = (summary.gate_decisions || 0) + 1;
    summary.gate_reason_codes ||= {};
    if (entry.reason_code) {
      summary.gate_reason_codes[entry.reason_code] = (summary.gate_reason_codes[entry.reason_code] || 0) + 1;
    }
  }
  if (entry.kind === "tool_decision") {
    summary.tool_decisions = (summary.tool_decisions || 0) + 1;
    summary.tool_rejections_by_reason ||= {};
    if (entry.status === "rejected" && entry.rejected_reason) {
      summary.tool_rejections_by_reason[entry.rejected_reason] =
        (summary.tool_rejections_by_reason[entry.rejected_reason] || 0) + 1;
    }
  }
  if (entry.route_used) {
    summary.requests_by_route[entry.route_used] = (summary.requests_by_route[entry.route_used] || 0) + 1;
  }
  if (entry.tool_requested) summary.tool_suggestions += 1;
  if (entry.tool_executed) summary.tool_executions += 1;
  if (entry.kind === "tool" && entry.status === "failed") summary.tool_denials += 1;
  if (entry.kind === "tool" && entry.status === "cancelled") summary.confirmation_cancellations += 1;
  if (entry.timeout) summary.timeout_count += 1;
  if (entry.runtime_crash) summary.runtime_crash_count += 1;
  if (entry.kind === "runtime_self_test") {
    summary.runtime_self_test_total += 1;
    if (entry.status === "failed") summary.runtime_self_test_failed_total += 1;
  }
  if (entry.kind === "runtime_start") {
    if (entry.status === "attempt") summary.runtime_start_attempt_total += 1;
    if (entry.status === "failed") summary.runtime_start_failed_total += 1;
  }
  if (entry.code) {
    summary.runtime_exit_code_counts ||= {};
    summary.runtime_exit_code_counts[entry.code] = (summary.runtime_exit_code_counts[entry.code] || 0) + 1;
  }
  if (entry.kind === "download" && entry.status === "success") summary.verified_downloads += 1;
  if (entry.kind === "download" && entry.status === "failed") summary.failed_downloads += 1;
  summary.durations = (Array.isArray(summary.durations) ? summary.durations : [])
    .filter(isValidTiming);
  if (isValidTiming(entry.duration_ms)) summary.durations.push(Number(entry.duration_ms));
  summary.durations = summary.durations.slice(-500);
  if (isValidTiming(entry.queue_wait_ms)) {
    summary.queue_wait_total_ms = Math.max(0, Number(summary.queue_wait_total_ms) || 0) + Number(entry.queue_wait_ms);
  }
  const stageKeys = [
    "deterministic_ms", "gate_ms", "queue_ms", "prompt_eval_ms", "generation_ms",
    "main_queue_ms", "main_generate_ms", "total_ms"
  ];
  if (entry.kind === "request" && stageKeys.some((key) => isValidTiming(entry[key]))) {
    summary.stage_totals ||= {};
    if (!summary.stage_counts) {
      const legacySamples = Math.max(0, Number(summary.stage_samples) || 0);
      summary.stage_counts = Object.fromEntries(
        Object.keys(summary.stage_totals)
          .filter((key) => isValidTiming(summary.stage_totals[key]))
          .map((key) => [key, legacySamples])
      );
    }
    for (const key of stageKeys) {
      if (!isValidTiming(entry[key])) continue;
      summary.stage_totals[key] = Math.max(0, Number(summary.stage_totals[key]) || 0) + Number(entry[key]);
      summary.stage_counts[key] = Math.max(0, Number(summary.stage_counts[key]) || 0) + 1;
    }
  }
  const totalCandidate = entry.total_ms ?? entry.duration_ms;
  const totalMs = isValidTiming(totalCandidate) ? Number(totalCandidate) : null;
  if (entry.kind === "request" && totalMs != null && totalMs >= 30000) {
    summary.slow_requests ||= [];
    summary.slow_requests.unshift({
      timestamp: new Date().toISOString(),
      request_id: entry.request_id || null,
      route_used: entry.route_used || null,
      route_class: entry.route_class || null,
      reason_code: entry.gate_reason_code || entry.reason_code || null,
      deterministic_ms: entry.deterministic_ms || 0,
      gate_ms: entry.gate_ms || 0,
      queue_ms: entry.queue_ms ?? entry.main_queue_ms ?? 0,
      prompt_eval_ms: entry.prompt_eval_ms || 0,
      generation_ms: entry.generation_ms ?? entry.main_generate_ms ?? 0,
      main_queue_ms: entry.main_queue_ms ?? entry.queue_ms ?? 0,
      main_generate_ms: entry.main_generate_ms ?? entry.generation_ms ?? 0,
      prompt_tokens: entry.prompt_tokens || 0,
      generated_tokens: entry.generated_tokens || 0,
      prompt_tps: entry.prompt_tps || 0,
      generation_tps: entry.generation_tps || 0,
      backend: entry.backend || null,
      gpu_layers: entry.gpu_layers || 0,
      context_size: entry.context_size || 0,
      max_output_tokens_used: entry.max_output_tokens_used ?? entry.max_output_tokens ?? 0,
      frontend_soft_timeout: Boolean(entry.frontend_soft_timeout),
      total_ms: totalMs,
      risk_504: totalMs >= 45000
    });
    summary.slow_requests = summary.slow_requests.slice(0, 25);
  }
  fs.writeFileSync(stateFile(), JSON.stringify(summary, null, 2));
  fs.appendFileSync(historyFile(), `${JSON.stringify({ timestamp:new Date().toISOString(), ...entry })}\n`);
}
function report() {
  return summarizeMetrics(getSummary());
}
function summarizeMetrics(s = {}) {
  const sorted = (Array.isArray(s.durations) ? s.durations : [])
    .filter(isValidTiming)
    .map(Number)
    .sort((a,b)=>a-b);
  const average_stage_ms = Object.fromEntries(
    Object.entries(s.stage_totals || {})
      .filter(([, value]) => isValidTiming(value))
      .map(([key, value]) => {
        const legacyCount = Math.max(0, Number(s.stage_samples) || 0);
        const count = Math.max(0, Number(s.stage_counts?.[key]) || legacyCount);
        return [key, count ? Math.max(0, Math.round(Number(value) / count)) : 0];
      })
  );
  return {
    ...s,
    durations: sorted,
    average_stage_ms,
    average_response_ms: sorted.length ? Math.max(0, Math.round(sorted.reduce((a,b)=>a+b,0)/sorted.length)) : 0,
    median_response_ms: sorted.length ? Math.max(0, sorted[Math.floor(sorted.length/2)]) : 0
  };
}
function history(limit=100) {
  try {
    return fs.readFileSync(historyFile(),"utf8").trim().split(/\r?\n/)
      .filter(Boolean)
      .map(parseHistoryRow)
      .filter(Boolean)
      .slice(-limit)
      .reverse();
  } catch { return []; }
}
function historyPage(page = 1, pageSize = 25) {
  const safePage = Math.max(1, Number.parseInt(page, 10) || 1);
  const safeSize = Math.max(1, Math.min(100, Number.parseInt(pageSize, 10) || 25));
  try {
    const rows = fs.readFileSync(historyFile(), "utf8").trim().split(/\r?\n/)
      .filter(Boolean)
      .map(parseHistoryRow)
      .filter(Boolean);
    return paginateRows(rows, safePage, safeSize);
  } catch {
    return { entries: [], page: 1, pages: 1, page_size: safeSize, total: 0 };
  }
}
function workHistoryPage(query = {}, page = 1, pageSize = 20) {
  const rows = readHistoryRows();
  const filters = normalizeWorkFilters(query);
  const grouped = groupWorkRows(rows)
    .filter((work) => matchesWorkFilters(work, filters));
  return paginateRows(grouped, page, pageSize);
}
function slowRequestsPage(page = 1, pageSize = 15) {
  const safePage = Math.max(1, Number.parseInt(page, 10) || 1);
  const safeSize = Math.max(1, Math.min(100, Number.parseInt(pageSize, 10) || 15));
  try {
    const rows = fs.readFileSync(historyFile(), "utf8").trim().split(/\r?\n/)
      .filter(Boolean)
      .map(parseHistoryRow)
      .filter((entry) => {
        const total = entry?.total_ms ?? entry?.duration_ms;
        return entry?.kind === "request" && isValidTiming(total) && Number(total) >= 30000;
      })
      .map(normalizeSlowEntry);
    return paginateRows(rows, safePage, safeSize);
  } catch {
    return { entries: [], page: 1, pages: 1, page_size: safeSize, total: 0 };
  }
}
function configureRetention(value = {}) {
  retention = normalizeRetention(value);
  applyRetention();
}
function applyRetention() {
  const rows = readHistoryRows();
  if (!rows.length) return;
  const keepIds = retainedWorkIds(groupWorkRows(rows), retention);
  if (!keepIds) return;
  const kept = rows.filter((row) => {
    const id = row.request_id || row.work_id;
    return !id || keepIds.has(id);
  });
  if (kept.length === rows.length) return;
  fs.writeFileSync(historyFile(), kept.map((row) => JSON.stringify(row)).join("\n") + (kept.length ? "\n" : ""));
}
function maybeApplyRetention() {
  if (Math.random() > 0.02) return;
  try { applyRetention(); } catch {}
}
function readHistoryRows() {
  try {
    return fs.readFileSync(historyFile(), "utf8").trim().split(/\r?\n/)
      .filter(Boolean)
      .map(parseHistoryRow)
      .filter(Boolean);
  } catch {
    return [];
  }
}
function groupWorkRows(rows) {
  const groups = new Map();
  for (const row of rows) {
    const id = row.request_id || row.work_id;
    if (!id) continue;
    if (!groups.has(id)) {
      groups.set(id, {
        work_id: id,
        started_at: row.timestamp,
        finished_at: row.timestamp,
        status: "success",
        source: row.origin || row.platform || "webui",
        user_id: row.user_id || "",
        role: row.role || "",
        internal_mode: row.controller_complexity || "",
        okf_retrieval: row.okf_retrieval_depth || "",
        reason_code: row.controller_reason_code || row.gate_reason_code || row.reason_code || "",
        processed_tokens: 0,
        final_tokens: 0,
        delivered_tokens: 0,
        duration_ms: 0,
        prompt: "",
        prompt_tokens: 0,
        has_error: false,
        has_refusal: false,
        has_fallback: false,
        has_truncation: false,
        has_okf_context: false,
        events: []
      });
    }
    const group = groups.get(id);
    group.started_at = earlierIso(group.started_at, row.timestamp);
    group.finished_at = laterIso(group.finished_at, row.timestamp);
    group.source = row.origin || row.platform || group.source;
    group.user_id = row.user_id || group.user_id;
    group.role = row.role || group.role;
    group.internal_mode = row.controller_complexity || group.internal_mode;
    group.okf_retrieval = row.okf_retrieval_depth || group.okf_retrieval;
    group.reason_code = row.controller_reason_code || row.gate_reason_code || row.reason_code || group.reason_code;
    group.has_error ||= row.status === "failed" || row.kind === "error" || Boolean(row.error_code);
    group.has_refusal ||= row.status === "refused" || row.route_used === "refusal";
    group.has_fallback ||= Boolean(row.controller_fallback_used || row.fallback_reason || row.rejected_reason);
    group.has_truncation ||= Boolean(row.truncated);
    group.has_okf_context ||= row.kind === "okf_retrieval" || row.okf_retrieval_depth === "light" || row.okf_retrieval_depth === "deep" || Number(row.okf_match_count) > 0;
    if (row.kind === "prompt") {
      group.prompt = row.prompt || group.prompt;
      group.prompt_tokens = validOrZero(row.prompt_tokens);
    }
    const promptTokens = validOrZero(row.prompt_tokens);
    const generatedTokens = validOrZero(row.generated_tokens);
    group.processed_tokens += promptTokens + generatedTokens;
    if (row.final_tokens != null) group.final_tokens = validOrZero(row.final_tokens);
    else if (row.final_reply_length != null || row.original_final_length != null) {
      group.final_tokens = estimateTokensFromChars(row.final_reply_length ?? row.original_final_length);
    }
    if (row.delivered_tokens != null) group.delivered_tokens = validOrZero(row.delivered_tokens);
    else if (row.delivered_length != null) group.delivered_tokens = estimateTokensFromChars(row.delivered_length);
    group.duration_ms = Math.max(group.duration_ms, validOrZero(row.total_ms ?? row.duration_ms));
    group.events.push(workEvent(row));
  }
  return [...groups.values()]
    .map((group) => {
      if (!group.processed_tokens) group.processed_tokens = group.prompt_tokens + group.final_tokens;
      if (group.has_error && !group.delivered_tokens) group.status = "failed";
      else if (group.has_error || group.has_refusal || group.has_fallback || group.has_truncation) group.status = "partial";
      else group.status = "success";
      group.events.sort((left, right) => String(left.timestamp).localeCompare(String(right.timestamp)));
      return group;
    })
    .sort((left, right) => String(left.started_at).localeCompare(String(right.started_at)));
}
function workEvent(row) {
  return {
    timestamp: row.timestamp,
    type: normalizeWorkEventType(row),
    status: row.status || "",
    summary: workEventSummary(row),
    prompt: row.kind === "prompt" ? row.prompt || "" : "",
    tokens: validOrZero(row.prompt_tokens) + validOrZero(row.generated_tokens),
    data: compactWorkData(row)
  };
}
function normalizeWorkEventType(row) {
  if (row.kind === "prompt") return "prompt";
  if (row.kind === "controller_decision") return "controller";
  if (row.kind === "gate_summary" || row.kind === "gate_decision") return "controller";
  if (row.kind === "okf_retrieval") return "okf_retrieval";
  if (row.kind === "prompt_build") return "prompt_build";
  if (row.kind === "model_request") return "model_request";
  if (row.kind === "request") return row.status === "failed" ? "error" : "model_response";
  if (row.kind === "delivery") return row.truncated ? "source_limit" : "delivery";
  if (row.kind === "tool_exposure") return "context";
  return row.kind || "metrics";
}
function workEventSummary(row) {
  if (row.kind === "prompt") return `Prompt from ${row.origin || row.platform || "webui"} as ${row.role || "unknown role"}`;
  if (row.kind === "controller_decision") {
    return `Controller selected ${row.controller_complexity || "-"} / ${row.okf_retrieval_depth || "-"} (${row.controller_reason_code || row.reason_code || "no reason"})`;
  }
  if (row.kind === "gate_summary" || row.kind === "gate_decision") {
    return `Gate route ${row.route_used || "-"} (${row.reason_code || "no reason"})`;
  }
  if (row.kind === "okf_retrieval") return `OKF retrieval ${row.status || "success"} with ${row.okf_match_count || 0} match(es)`;
  if (row.kind === "prompt_build") return `Prompt built with ${row.context_block_count || 0} context block(s)`;
  if (row.kind === "model_request") return `Main model request in ${row.controller_complexity || "dynamic"} mode`;
  if (row.kind === "delivery") return row.truncated ? "Delivered after source limit truncation" : "Delivered reply";
  if (row.kind === "request" && row.status === "failed") return row.message || row.error_code || "Request failed";
  return row.reason_code || row.controller_reason_code || row.status || row.kind || "Event";
}
function compactWorkData(row) {
  const keys = [
    "route_used", "route_class", "reason_code", "gate_reason_code", "controller_intent",
    "controller_complexity", "okf_retrieval_depth", "answer_style", "source_profile",
    "controller_confidence", "okf_match_count", "context_block_count", "prompt_tokens",
    "generated_tokens", "final_tokens", "delivered_tokens", "final_reply_length",
    "delivered_length", "truncated", "delivery_action", "fallback_reason", "rejected_reason", "error_code"
  ];
  return Object.fromEntries(keys.filter((key) => row[key] != null).map((key) => [key, row[key]]));
}
function normalizeWorkFilters(query = {}) {
  return {
    q: String(query.work_q || query.q || "").trim().toLowerCase(),
    status: String(query.work_status || "").trim(),
    source: String(query.work_source || "").trim(),
    role: String(query.work_role || "").trim(),
    mode: String(query.work_mode || "").trim(),
    okf: String(query.work_okf || "").trim(),
    flag: String(query.work_flag || "").trim(),
    from: parseTime(query.work_from),
    to: parseTime(query.work_to, true)
  };
}
function matchesWorkFilters(work, filters) {
  if (filters.status && work.status !== filters.status) return false;
  if (filters.source && work.source !== filters.source) return false;
  if (filters.role && work.role !== filters.role) return false;
  if (filters.mode && work.internal_mode !== filters.mode) return false;
  if (filters.okf && work.okf_retrieval !== filters.okf) return false;
  if (filters.flag === "error" && !work.has_error) return false;
  if (filters.flag === "refusal" && !work.has_refusal) return false;
  if (filters.flag === "fallback" && !work.has_fallback) return false;
  if (filters.flag === "truncation" && !work.has_truncation) return false;
  if (filters.flag === "okf" && !work.has_okf_context) return false;
  const started = Date.parse(work.started_at);
  if (filters.from && started < filters.from) return false;
  if (filters.to && started > filters.to) return false;
  if (!filters.q) return true;
  const haystack = [
    work.work_id, work.prompt, work.source, work.user_id, work.role, work.status, work.internal_mode,
    work.okf_retrieval, work.reason_code,
    ...work.events.map((event) => `${event.type} ${event.status} ${event.summary} ${JSON.stringify(event.data)}`)
  ].join("\n").toLowerCase();
  return haystack.includes(filters.q);
}
function normalizeRetention(value = {}) {
  const mode = value.mode === "age" ? "age" : "count";
  return {
    mode,
    count: Math.max(50, Math.min(10000, Number.parseInt(value.count, 10) || 500)),
    age_value: Math.max(1, Math.min(1000, Number.parseInt(value.age_value, 10) || 30)),
    age_unit: ["hours", "days", "weeks", "months", "years"].includes(value.age_unit) ? value.age_unit : "days"
  };
}
function retainedWorkIds(groups, config) {
  if (config.mode === "count") {
    return new Set(groups.slice(-config.count).map((group) => group.work_id));
  }
  const cutoff = Date.now() - ageMs(config.age_value, config.age_unit);
  return new Set(groups.filter((group) => Date.parse(group.started_at) >= cutoff).map((group) => group.work_id));
}
function ageMs(value, unit) {
  const hours = unit === "hours" ? value
    : unit === "weeks" ? value * 24 * 7
      : unit === "months" ? value * 24 * 30
        : unit === "years" ? value * 24 * 365
          : value * 24;
  return hours * 60 * 60 * 1000;
}
function parseTime(value, endOfDay = false) {
  if (!value) return null;
  const date = new Date(value);
  if (Number.isNaN(date.getTime())) return null;
  if (endOfDay && /^\d{4}-\d{2}-\d{2}$/.test(String(value))) date.setHours(23, 59, 59, 999);
  return date.getTime();
}
function earlierIso(left, right) {
  return Date.parse(left) <= Date.parse(right) ? left : right;
}
function laterIso(left, right) {
  return Date.parse(left) >= Date.parse(right) ? left : right;
}
function estimateTokensFromChars(value) {
  const number = Number(value);
  return Number.isFinite(number) && number > 0 ? Math.max(1, Math.ceil(number / 4)) : 0;
}
function paginateRows(rows, page = 1, pageSize = 25, map = (value) => value) {
  const total = rows.length;
  const pages = Math.max(1, Math.ceil(total / pageSize));
  const current = Math.min(Math.max(1, page), pages);
  const end = total - (current - 1) * pageSize;
  const start = Math.max(0, end - pageSize);
  return {
    entries: rows.slice(start, end).reverse().map(map),
    page: current,
    pages,
    page_size: pageSize,
    total
  };
}

function parseHistoryRow(value) {
  try { return JSON.parse(value); }
  catch { return null; }
}

function normalizeSlowEntry(entry) {
  const totalMs = Number(entry.total_ms ?? entry.duration_ms);
  return {
    ...entry,
    total_ms: totalMs,
    queue_ms: validOrZero(entry.queue_ms ?? entry.main_queue_ms),
    prompt_eval_ms: validOrZero(entry.prompt_eval_ms),
    generation_ms: validOrZero(entry.generation_ms ?? entry.main_generate_ms),
    gate_ms: validOrZero(entry.gate_ms),
    prompt_tokens: validOrZero(entry.prompt_tokens),
    generated_tokens: validOrZero(entry.generated_tokens),
    prompt_tps: validOrZero(entry.prompt_tps),
    generation_tps: validOrZero(entry.generation_tps),
    max_output_tokens_used: validOrZero(entry.max_output_tokens_used ?? entry.max_output_tokens),
    risk_504: totalMs >= 45000
  };
}

function isValidTiming(value) {
  const number = Number(value);
  return Number.isFinite(number) && number >= 0;
}

function validOrZero(value) {
  return isValidTiming(value) ? Number(value) : 0;
}

module.exports = {
  configureRetention,
  applyRetention,
  record,
  report,
  history,
  historyPage,
  workHistoryPage,
  slowRequestsPage,
  paginateRows,
  isValidTiming,
  summarizeMetrics
};