import fs from "node:fs";
import path from "node:path";
import type { RequestPipelinePayloads } from "@omniroute/open-sse/utils/requestLogger.ts";
import { resolveDataDir } from "../dataPaths";
import { getCallLogPipelineMaxSizeBytes, isChatDebugFileEnabled } from "../logEnv";

const isCloud = typeof globalThis.caches === "object" && globalThis.caches !== null;
const isBuildPhase = process.env.NEXT_PHASE === "phase-production-build";
const DATA_DIR = resolveDataDir({ isCloud });

export const CALL_LOGS_DIR = isCloud ? null : path.join(DATA_DIR, "call_logs");
export const MAX_CALL_LOG_ARTIFACT_BYTES = 512 * 1024;

const SIZE_LIMIT_EXCEEDED_REASON = "call_log_artifact_size_limit_exceeded";
const OMITTED_FOR_SIZE_LIMIT = "[omitted: call log artifact size limit exceeded]";
const STREAM_CHUNKS_OMITTED_FOR_SIZE_LIMIT =
  "[stream chunks omitted: call log artifact size limit exceeded]";

export type CallLogDetailState = "none" | "ready" | "missing" | "corrupt" | "legacy-inline";

export type CallLogArtifact = {
  schemaVersion: 5;
  summary: {
    id: string;
    timestamp: string;
    method: string;
    path: string;
    status: number;
    model: string;
    requestedModel: string | null;
    provider: string;
    account: string;
    connectionId: string | null;
    duration: number;
    tokens: {
      in: number;
      out: number;
      cacheRead: number | null;
      cacheWrite: number | null;
      reasoning: number | null;
      compressed: number | null;
    };
    requestType: string | null;
    sourceFormat: string | null;
    targetFormat: string | null;
    apiKeyId: string | null;
    apiKeyName: string | null;
    comboName: string | null;
    comboStepId: string | null;
    comboExecutionKey: string | null;
  };
  requestBody: unknown;
  responseBody: unknown;
  error: unknown;
  pipeline?: RequestPipelinePayloads;
};

export type CallLogArtifactWriteResult = {
  relPath: string;
  sizeBytes: number;
  sha256: string;
};

export function buildArtifactRelativePath(timestamp: string, id: string) {
  const parsed = new Date(timestamp);
  const safeTimestamp = (
    Number.isNaN(parsed.getTime()) ? new Date().toISOString() : parsed.toISOString()
  ).replace(/[:]/g, "-");
  const dateFolder = safeTimestamp.slice(0, 10);
  return path.posix.join(dateFolder, `${safeTimestamp}_${id}.json`);
}

function computeArtifactChecksum(serialized: string): string {
  const bytes = Buffer.from(serialized);
  let hash = 0x811c9dc5;
  for (const byte of bytes) {
    hash ^= byte;
    hash = Math.imul(hash, 0x01000193) >>> 0;
  }
  return hash.toString(16).padStart(8, "0");
}

function truncateArtifactForStorage(artifact: CallLogArtifact): CallLogArtifact {
  const pipeline = artifact.pipeline;
  if (!pipeline?.streamChunks) return artifact;

  return {
    ...artifact,
    pipeline: {
      ...pipeline,
      streamChunks: {
        provider: pipeline.streamChunks.provider?.length
          ? [STREAM_CHUNKS_OMITTED_FOR_SIZE_LIMIT]
          : undefined,
        openai: pipeline.streamChunks.openai?.length
          ? [STREAM_CHUNKS_OMITTED_FOR_SIZE_LIMIT]
          : undefined,
        client: pipeline.streamChunks.client?.length
          ? [STREAM_CHUNKS_OMITTED_FOR_SIZE_LIMIT]
          : undefined,
      },
    },
  };
}

function omitOversizedPipeline(artifact: CallLogArtifact): CallLogArtifact {
  if (!artifact.pipeline) return artifact;

  return {
    ...artifact,
    pipeline: {
      error: {
        _omniroute_truncated: true,
        reason: SIZE_LIMIT_EXCEEDED_REASON,
      },
    },
  };
}

function getArtifactMaxBytes(artifact: CallLogArtifact): number {
  return artifact.pipeline ? getCallLogPipelineMaxSizeBytes() : MAX_CALL_LOG_ARTIFACT_BYTES;
}

function buildMinimalArtifactForSizeLimit(artifact: CallLogArtifact) {
  return {
    schemaVersion: artifact.schemaVersion,
    summary: artifact.summary,
    requestBody: OMITTED_FOR_SIZE_LIMIT,
    responseBody: OMITTED_FOR_SIZE_LIMIT,
    error: artifact.error ? OMITTED_FOR_SIZE_LIMIT : null,
    pipeline: {
      error: {
        _omniroute_truncated: true,
        reason: SIZE_LIMIT_EXCEEDED_REASON,
      },
    },
  };
}

function serializeFinalSizeLimitFallback(artifact: CallLogArtifact, maxBytes: number): string {
  const withSummary = JSON.stringify(buildMinimalArtifactForSizeLimit(artifact));
  if (Buffer.byteLength(withSummary) <= maxBytes) {
    return withSummary;
  }

  return JSON.stringify({
    schemaVersion: artifact.schemaVersion,
    _omniroute_truncated: true,
    reason: SIZE_LIMIT_EXCEEDED_REASON,
  });
}

function serializeArtifactForStorage(artifact: CallLogArtifact): string {
  // Debug mode: write full untruncated payload
  if (isChatDebugFileEnabled()) {
    return JSON.stringify(artifact, null, 2);
  }

  const maxBytes = getArtifactMaxBytes(artifact);
  const serialized = JSON.stringify(artifact, null, 2);
  if (Buffer.byteLength(serialized) <= maxBytes) {
    return serialized;
  }

  const truncated = JSON.stringify(truncateArtifactForStorage(artifact), null, 2);
  if (Buffer.byteLength(truncated) <= maxBytes) {
    return truncated;
  }

  const withoutPipeline = JSON.stringify(omitOversizedPipeline(artifact), null, 2);
  if (Buffer.byteLength(withoutPipeline) <= maxBytes) {
    return withoutPipeline;
  }

  const minimal = JSON.stringify(
    {
      ...omitOversizedPipeline(artifact),
      requestBody: OMITTED_FOR_SIZE_LIMIT,
      responseBody: OMITTED_FOR_SIZE_LIMIT,
      error: artifact.error ? OMITTED_FOR_SIZE_LIMIT : null,
    },
    null,
    2
  );
  if (Buffer.byteLength(minimal) <= maxBytes) {
    return minimal;
  }

  return serializeFinalSizeLimitFallback(artifact, maxBytes);
}

export function writeCallArtifact(
  artifact: CallLogArtifact,
  relativePath = buildArtifactRelativePath(artifact.summary.timestamp, artifact.summary.id)
): CallLogArtifactWriteResult | null {
  if (!CALL_LOGS_DIR || isBuildPhase) return null;

  const absPath = path.join(CALL_LOGS_DIR, relativePath);
  const tmpPath = `${absPath}.${process.pid}.${Date.now()}.tmp`;

  try {
    const serialized = serializeArtifactForStorage(artifact);
    const sizeBytes = Buffer.byteLength(serialized);
    // Keep the legacy field name for storage compatibility, but use a non-cryptographic checksum
    // so artifact bookkeeping is not treated as password hashing by static analysis.
    const fileChecksum = computeArtifactChecksum(serialized);

    fs.mkdirSync(path.dirname(absPath), { recursive: true });
    fs.writeFileSync(tmpPath, serialized);
    fs.renameSync(tmpPath, absPath);

    return {
      relPath: relativePath,
      sizeBytes,
      sha256: fileChecksum,
    };
  } catch (error) {
    try {
      fs.rmSync(tmpPath, { force: true });
    } catch {
      // Best effort cleanup only.
    }
    console.error("[callLogs] Failed to write request artifact:", (error as Error).message);
    return null;
  }
}

export function readCallArtifact(relativePath: string | null): {
  artifact: CallLogArtifact | null;
  state: "ready" | "missing" | "corrupt";
} {
  if (!CALL_LOGS_DIR || !relativePath) {
    return { artifact: null, state: "missing" };
  }

  try {
    const absPath = path.join(CALL_LOGS_DIR, relativePath);
    if (!fs.existsSync(absPath)) {
      return { artifact: null, state: "missing" };
    }
    return {
      artifact: JSON.parse(fs.readFileSync(absPath, "utf8")) as CallLogArtifact,
      state: "ready",
    };
  } catch (error) {
    console.error("[callLogs] Failed to read request artifact:", (error as Error).message);
    return { artifact: null, state: "corrupt" };
  }
}

export function deleteCallArtifact(relativePath: string | null): boolean {
  if (!CALL_LOGS_DIR || !relativePath) return false;

  try {
    const absPath = path.join(CALL_LOGS_DIR, relativePath);
    if (!fs.existsSync(absPath)) return false;
    fs.rmSync(absPath, { force: true });
    return true;
  } catch {
    return false;
  }
}

export function cleanupEmptyCallLogDirs(baseDir = CALL_LOGS_DIR) {
  if (!baseDir || !fs.existsSync(baseDir)) return;

  try {
    for (const entry of fs.readdirSync(baseDir)) {
      const entryPath = path.join(baseDir, entry);
      const stat = fs.statSync(entryPath);
      if (!stat.isDirectory()) continue;
      if (fs.readdirSync(entryPath).length === 0) {
        fs.rmSync(entryPath, { recursive: true, force: true });
      }
    }
  } catch {
    // Best effort only.
  }
}

export function listCallLogArtifactFiles(baseDir = CALL_LOGS_DIR) {
  if (!baseDir || !fs.existsSync(baseDir)) return [];

  return fs
    .readdirSync(baseDir)
    .flatMap((entry) => {
      const entryPath = path.join(baseDir, entry);
      try {
        const stat = fs.statSync(entryPath);
        if (!stat.isDirectory()) return [];

        return fs
          .readdirSync(entryPath)
          .filter((file) => file.endsWith(".json"))
          .map((file) => {
            const absPath = path.join(entryPath, file);
            const fileStat = fs.statSync(absPath);
            return {
              relativePath: path.posix.join(entry, file),
              absPath,
              mtimeMs: fileStat.mtimeMs,
            };
          });
      } catch {
        return [];
      }
    })
    .sort((a, b) => b.mtimeMs - a.mtimeMs);
}