snapshot!

4 files changed, 195 insertions, 0 deletions

diff --git a/u/trace/itrace.ts b/u/trace/itrace.ts
new file mode 100644
index 0000000..b483067
--- /dev/null
+++ b/u/trace/itrace.ts
@@ -0,0 +1,72 @@
+import { Mapper, SideEffect } from "../fn/mod.ts";
+
+export interface ITrace<TracingW> {
+  addTrace: Mapper<TracingW, ITrace<TracingW>>;
+  trace: SideEffect<TracingW>;
+}
+
+export type ITraceableTuple<T, Trace> = [T, Trace];
+export type ITraceableMapper<T, Trace, U, W = ITraceable<T, Trace>> = (
+  w: W,
+) => U;
+
+export interface ITraceable<T, Trace> {
+  readonly item: T;
+  readonly trace: ITrace<Trace>;
+
+  move<U>(u: U): ITraceable<U, Trace>;
+  map: <U>(
+    mapper: ITraceableMapper<T, Trace, U>,
+  ) => ITraceable<U, Trace>;
+  bimap: <U>(
+    mapper: ITraceableMapper<T, Trace, ITraceableTuple<U, Trace>>,
+  ) => ITraceable<U, Trace>;
+  peek: (peek: ITraceableMapper<T, Trace, void>) => ITraceable<T, Trace>;
+  flatMap: <U>(
+    mapper: ITraceableMapper<T, Trace, ITraceable<U, Trace>>,
+  ) => ITraceable<U, Trace>;
+  flatMapAsync<U>(
+    mapper: ITraceableMapper<T, Trace, Promise<ITraceable<U, Trace>>>,
+  ): ITraceable<Promise<U>, Trace>;
+}
+
+export class TraceableImpl<T, L> implements ITraceable<T, L> {
+  protected constructor(
+    readonly item: T,
+    readonly trace: ITrace<L>,
+  ) {}
+
+  public map<U>(mapper: ITraceableMapper<T, L, U>) {
+    const result = mapper(this);
+    return new TraceableImpl(result, this.trace);
+  }
+
+  public flatMap<U>(
+    mapper: ITraceableMapper<T, L, ITraceable<U, L>>,
+  ): ITraceable<U, L> {
+    return mapper(this);
+  }
+
+  public flatMapAsync<U>(
+    mapper: ITraceableMapper<T, L, Promise<ITraceable<U, L>>>,
+  ): ITraceable<Promise<U>, L> {
+    return new TraceableImpl(
+      mapper(this).then(({ item }) => item),
+      this.trace,
+    );
+  }
+
+  public peek(peek: ITraceableMapper<T, L, void>) {
+    peek(this);
+    return this;
+  }
+
+  public move<Tt>(t: Tt): ITraceable<Tt, L> {
+    return this.map(() => t);
+  }
+
+  public bimap<U>(mapper: ITraceableMapper<T, L, ITraceableTuple<U, L>>) {
+    const [item, trace] = mapper(this);
+    return new TraceableImpl(item, this.trace.addTrace(trace));
+  }
+}
diff --git a/u/trace/logger.ts b/u/trace/logger.ts
new file mode 100644
index 0000000..79da367
--- /dev/null
+++ b/u/trace/logger.ts
@@ -0,0 +1,86 @@
+import {
+  isDebug,
+  isObject,
+  type ITrace,
+  type SideEffect,
+  type Supplier,
+} from "@emprespresso/utils";
+
+export interface ILogger {
+  log: (...args: unknown[]) => void;
+  debug: (...args: unknown[]) => void;
+  warn: (...args: unknown[]) => void;
+  error: (...args: unknown[]) => void;
+}
+export type ILoggerLevel = "UNKNOWN" | "INFO" | "WARN" | "DEBUG" | "ERROR";
+const logLevelOrder: Array<ILoggerLevel> = ["DEBUG", "INFO", "WARN", "ERROR"];
+const defaultAllowedLevels = () =>
+  [
+    "UNKNOWN",
+    ...(isDebug() ? ["DEBUG"] : []),
+    "INFO",
+    "WARN",
+    "ERROR",
+  ] as Array<ILoggerLevel>;
+
+export const logWithLevel = (
+  logger: ILogger,
+  level: ILoggerLevel,
+): SideEffect<unknown> => {
+  switch (level) {
+    case "UNKNOWN":
+    case "INFO":
+      return logger.log;
+    case "DEBUG":
+      return logger.debug;
+    case "WARN":
+      return logger.warn;
+    case "ERROR":
+      return logger.error;
+  }
+};
+
+export const LoggerImpl = console;
+
+export type LogTraceSupplier = string | Supplier<string> | {
+  level: ILoggerLevel;
+};
+
+const foldTraces = (traces: Array<LogTraceSupplier>) => {
+  const { line, level } = traces.reduce(
+    (acc: { line: string; level: number }, t) => {
+      if (isObject(t) && "level" in t) {
+        return {
+          ...acc,
+          level: Math.max(logLevelOrder.indexOf(t.level), acc.level),
+        };
+      }
+      const prefix = [
+        acc.line,
+        typeof t === "function" ? t() : t,
+      ].join(" ");
+      return { ...acc, prefix };
+    },
+    { line: "", level: -1 },
+  );
+  return { line, level: logLevelOrder[level] ?? "UNKNOWN" };
+};
+
+const defaultTrace = () => `[${new Date().toISOString()}]`;
+export const LogTrace = (
+  logger: ILogger,
+  traces: Array<LogTraceSupplier> = [defaultTrace],
+  allowedLevels: Supplier<Array<ILoggerLevel>> = defaultAllowedLevels,
+  defaultLevel: ILoggerLevel = "INFO",
+): ITrace<LogTraceSupplier> => {
+  return {
+    addTrace: (trace: LogTraceSupplier) =>
+      LogTrace(logger, traces.concat(trace)),
+    trace: (trace: LogTraceSupplier) => {
+      const { line, level: _level } = foldTraces(traces.concat(trace));
+      if (!allowedLevels().includes(_level)) return;
+      const level = _level === "UNKNOWN" ? defaultLevel : _level;
+      logWithLevel(logger, level)(`[${level}]${line}`);
+    },
+  };
+};
diff --git a/u/trace/mod.ts b/u/trace/mod.ts
new file mode 100644
index 0000000..9c42858
--- /dev/null
+++ b/u/trace/mod.ts
@@ -0,0 +1,3 @@
+export * from "./itrace.ts";
+export * from "./logger.ts";
+export * from "./trace.ts";
diff --git a/u/trace/trace.ts b/u/trace/trace.ts
new file mode 100644
index 0000000..5d5c59b
--- /dev/null
+++ b/u/trace/trace.ts
@@ -0,0 +1,34 @@
+import type { Callable } from "@emprespresso/utils";
+import {
+  type ITraceableMapper,
+  type ITraceableTuple,
+  TraceableImpl,
+  TraceableLogger,
+} from "./mod.ts";
+
+export class Traceable<T> extends TraceableImpl<T, TraceableLogger> {
+  static from<T>(t: T) {
+    return new Traceable(t, new TraceableLogger());
+  }
+
+  static withFunctionTrace<F extends Callable, T>(
+    f: F,
+  ): ITraceableMapper<T, TraceableLogger, ITraceableTuple<T>> {
+    return (t) => [t.item, f.name];
+  }
+
+  static withClassTrace<C extends object, T>(
+    c: C,
+  ): ITraceableMapper<T, TraceableLogger, ITraceableTuple<T>> {
+    return (t) => [t.item, c.constructor.name];
+  }
+
+  static promiseify<T, U>(
+    mapper: ITraceableMapper<T, TraceableLogger, U>,
+  ): ITraceableMapper<Promise<T>, TraceableLogger, Promise<U>> {
+    return (traceablePromise) =>
+      traceablePromise.flatMapAsync(async (t) =>
+        t.move(await t.item).map(mapper)
+      ).item;
+  }
+}