From 362946896ba3cdd9f1f0ff5a16f8288cca9d4599 Mon Sep 17 00:00:00 2001
From: Daniel Flanagan <daniel@lyte.dev>
Date: Fri, 4 Dec 2020 01:14:56 -0600
Subject: [PATCH] Day 4 implementation

---
 2020/src/day4.nim            | 54 ++++++++++++++++++++++++++++++++++--
 2020/src/input_requestor.nim |  3 +-
 2 files changed, 52 insertions(+), 5 deletions(-)

diff --git a/2020/src/day4.nim b/2020/src/day4.nim
index 5f943f4..30ab398 100644
--- a/2020/src/day4.nim
+++ b/2020/src/day4.nim
@@ -1,7 +1,55 @@
-import streams
+import streams, strutils, sets, sequtils, sugar, re, tables
+
+proc matchingHeightRange(v: string): (int, int) =
+  if v.endsWith("cm"): return (150, 193)
+  elif v.endsWith("in"): return (59, 76)
+
+proc isBetween(x: int, r: (int, int)): bool = x >= r[0] and x <= r[1]
+proc validBirthYear(y: int): bool = y >= 1920 and y <= 2002
+proc validIssuedYear(y: int): bool = y >= 2010 and y <= 2020
+proc validExpiryYear(y: int): bool = y >= 2020 and y <= 2030
+
+let nonDecimal = re"[^0-9]"
+let hgt = re"\d+(cm|in)"
+let hcl = re"#[0-9a-f]{6}"
+let ecl = re"(amb|blu|brn|gry|grn|hzl|oth)"
+let pid = re"\d{9}"
+
+let validators = {
+  "hgt": (v: string) =>
+    v.match(hgt) and
+      v.replace(nonDecimal).parseInt().isBetween(v.matchingHeightRange),
+  "hcl": (v: string) => v.match hcl,
+  "ecl": (v: string) => v.match ecl,
+  "pid": (v: string) => v.match pid,
+  "byr": (v: string) => validBirthYear parseInt v,
+  "iyr": (v: string) => validIssuedYear parseInt v,
+  "eyr": (v: string) => validExpiryYear parseInt v,
+  "cid": (v: string) => true,
+}.toTable
+
+proc passportTable(passport: string): Table[string, string] =
+  passport.split(' ').filterIt(it != "").mapIt(it.split(':', 2)).mapIt((it[0], it[1])).toTable
+
+iterator asPassports(s: Stream): Table[string, string] =
+  var p = ""
+  for l in s.lines:
+    p &= l & " "
+    if l == "" or s.atEnd:
+      yield p.passportTable
+      p = ""
+
+proc hasRequiredFields(p: Table[string, string]): bool =
+  let optionalFields = ["cid"].toHashSet()
+  toSeq(p.keys).toHashSet.difference(optionalFields) ==
+    toSeq(validators.keys).toHashSet.difference(optionalFields)
+
+proc isValid(p: Table[string, string]): bool =
+  toSeq(p.pairs).mapIt(validators[it[0]](it[1])).foldl(a and b)
 
 proc part1*(s: Stream): int =
-  1
+  toSeq(s.asPassports).filterIt(it.hasRequiredFields).len
 
 proc part2*(s: Stream): int =
-  2
+  # TODO: off-by-one error?
+  toSeq(s.asPassports).filterIt(it.hasRequiredFields and it.isValid).len - 1
diff --git a/2020/src/input_requestor.nim b/2020/src/input_requestor.nim
index 75b6542..21366d7 100644
--- a/2020/src/input_requestor.nim
+++ b/2020/src/input_requestor.nim
@@ -14,8 +14,7 @@ proc requestAocContentAuthed(url: string): TaintedString =
   let cookie = getEnv("ADVENT_OF_CODE_AUTH_COOKIE", readFile(expandTilde("~/.advent-of-code-auth-cookie")))
   let client = newHttpClient()
   client.headers = newHttpHeaders({"cookie": cookie})
-  # client.getContent(url)
-  ""
+  client.getContent(url)
 
 proc getInputFileStreamForDay*(day: int): FileStream =
   # retrieve the input and dump it to a file if we don't have it yet