use haystack for search

for some reason it doesn't find Karlsruhe, but basically everything else??

gleam.toml

@@ -14,6 +14,7 @@ gleam_stdlib = "~> 0.19"
 gleam_http = "~> 3.0"
 mist = "~> 0.4"
 gleam_hackney = "~> 1.0"
+haystack = "~> 0.1"
 
 [dev-dependencies]
 gleeunit = "~> 0.6"

manifest.toml

@@ -3,20 +3,24 @@
 
 packages = [
   { name = "certifi", version = "2.9.0", build_tools = ["rebar3"], requirements = [], otp_app = "certifi", source = "hex", outer_checksum = "266DA46BDB06D6C6D35FDE799BCB28D36D985D424AD7C08B5BB48F5B5CDD4641" },
+  { name = "decimal", version = "2.1.1", build_tools = ["mix"], requirements = [], otp_app = "decimal", source = "hex", outer_checksum = "53CFE5F497ED0E7771AE1A475575603D77425099BA5FAEF9394932B35020FFCC" },
   { name = "gleam_erlang", version = "0.18.1", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_erlang", source = "hex", outer_checksum = "C69F59D086AD50B80DE294FB0963550630971C9DC04E92B1F7AEEDD2C0BE226C" },
   { name = "gleam_hackney", version = "1.0.0", build_tools = ["gleam"], requirements = ["gleam_http", "gleam_stdlib", "hackney"], otp_app = "gleam_hackney", source = "hex", outer_checksum = "B3C1E6BD138D57252F9F9E499C741E9227EE7EE9B017CA650EC8193E02F734E1" },
   { name = "gleam_http", version = "3.2.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_http", source = "hex", outer_checksum = "D034F5CE0639CD142CBA210B7D5D14236C284B0C5772A043D2E22128594573AE" },
   { name = "gleam_otp", version = "0.5.3", build_tools = ["gleam"], requirements = ["gleam_erlang", "gleam_stdlib"], otp_app = "gleam_otp", source = "hex", outer_checksum = "6E705B69464237353E0380AC8143BDB29A3F0BF6168755D5F2D6E55A34A8B077" },
   { name = "gleam_stdlib", version = "0.28.1", build_tools = ["gleam"], requirements = [], otp_app = "gleam_stdlib", source = "hex", outer_checksum = "73F0A89FADE5022CBEF6D6C3551F9ADCE7054AFCE0CB1DC4C6D5AB4CA62D0111" },
   { name = "gleeunit", version = "0.10.1", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleeunit", source = "hex", outer_checksum = "ECEA2DE4BE6528D36AFE74F42A21CDF99966EC36D7F25DEB34D47DD0F7977BAF" },
-  { name = "glisten", version = "0.7.0", build_tools = ["gleam"], requirements = ["gleam_erlang", "gleam_stdlib", "gleam_otp"], otp_app = "glisten", source = "hex", outer_checksum = "52B530FF25370590843998D1B6C4EC6169DB1300D5E4407A5CDA1575374B7AEC" },
+  { name = "glisten", version = "0.7.0", build_tools = ["gleam"], requirements = ["gleam_erlang", "gleam_otp", "gleam_stdlib"], otp_app = "glisten", source = "hex", outer_checksum = "52B530FF25370590843998D1B6C4EC6169DB1300D5E4407A5CDA1575374B7AEC" },
-  { name = "hackney", version = "1.18.1", build_tools = ["rebar3"], requirements = ["certifi", "metrics", "mimerl", "ssl_verify_fun", "idna", "parse_trans", "unicode_util_compat"], otp_app = "hackney", source = "hex", outer_checksum = "A4ECDAFF44297E9B5894AE499E9A070EA1888C84AFDD1FD9B7B2BC384950128E" },
+  { name = "hackney", version = "1.18.1", build_tools = ["rebar3"], requirements = ["idna", "metrics", "parse_trans", "ssl_verify_fun", "mimerl", "certifi", "unicode_util_compat"], otp_app = "hackney", source = "hex", outer_checksum = "A4ECDAFF44297E9B5894AE499E9A070EA1888C84AFDD1FD9B7B2BC384950128E" },
+  { name = "haystack", version = "0.1.0", build_tools = ["mix"], requirements = ["jason", "stemmer"], otp_app = "haystack", source = "hex", outer_checksum = "27A582513EF933C1B11345B96F8D41EE137D03B25312BD85068FFE8FEC503635" },
   { name = "idna", version = "6.1.1", build_tools = ["rebar3"], requirements = ["unicode_util_compat"], otp_app = "idna", source = "hex", outer_checksum = "92376EB7894412ED19AC475E4A86F7B413C1B9FBB5BD16DCCD57934157944CEA" },
+  { name = "jason", version = "1.4.0", build_tools = ["mix"], requirements = ["decimal"], otp_app = "jason", source = "hex", outer_checksum = "79A3791085B2A0F743CA04CEC0F7BE26443738779D09302E01318F97BDB82121" },
   { name = "metrics", version = "1.0.1", build_tools = ["rebar3"], requirements = [], otp_app = "metrics", source = "hex", outer_checksum = "69B09ADDDC4F74A40716AE54D140F93BEB0FB8978D8636EADED0C31B6F099F16" },
   { name = "mimerl", version = "1.2.0", build_tools = ["rebar3"], requirements = [], otp_app = "mimerl", source = "hex", outer_checksum = "F278585650AA581986264638EBF698F8BB19DF297F66AD91B18910DFC6E19323" },
-  { name = "mist", version = "0.10.0", build_tools = ["gleam"], requirements = ["gleam_erlang", "gleam_stdlib", "gleam_otp", "glisten", "gleam_http"], otp_app = "mist", source = "hex", outer_checksum = "5AFBABABF738BAB8720F047471051E4E9D102CA4694C120DB899FA12AD5D180B" },
+  { name = "mist", version = "0.10.0", build_tools = ["gleam"], requirements = ["gleam_stdlib", "gleam_otp", "glisten", "gleam_http", "gleam_erlang"], otp_app = "mist", source = "hex", outer_checksum = "5AFBABABF738BAB8720F047471051E4E9D102CA4694C120DB899FA12AD5D180B" },
   { name = "parse_trans", version = "3.3.1", build_tools = ["rebar3"], requirements = [], otp_app = "parse_trans", source = "hex", outer_checksum = "07CD9577885F56362D414E8C4C4E6BDF10D43A8767ABB92D24CBE8B24C54888B" },
   { name = "ssl_verify_fun", version = "1.1.6", build_tools = ["mix", "rebar3", "make"], requirements = [], otp_app = "ssl_verify_fun", source = "hex", outer_checksum = "BDB0D2471F453C88FF3908E7686F86F9BE327D065CC1EC16FA4540197EA04680" },
+  { name = "stemmer", version = "1.1.0", build_tools = ["mix"], requirements = [], otp_app = "stemmer", source = "hex", outer_checksum = "0CB5FAF73476B84500E371FF39FD9A494F60AB31D991689C1CD53B920556228F" },
   { name = "unicode_util_compat", version = "0.7.0", build_tools = ["rebar3"], requirements = [], otp_app = "unicode_util_compat", source = "hex", outer_checksum = "25EEE6D67DF61960CF6A794239566599B09E17E668D3700247BC498638152521" },
 ]
 
@@ -25,4 +29,5 @@ gleam_hackney = "~> 1.0"
 gleam_http = "~> 3.0"
 gleam_stdlib = "~> 0.19"
 gleeunit = "~> 0.6"
+haystack = "~> 0.1"
 mist = "~> 0.4"

src/bahnhofname.gleam

@@ -3,70 +3,62 @@ import gleam/http/request.{Request}
 import gleam/http.{Get}
 import gleam/bit_builder.{BitBuilder}
 import gleam/erlang/process
+import gleam/erlang/atom
 import gleam/io
 import gleam/int
 import gleam/string
 import gleam/bit_string
 import gleam/list
 import gleam/map.{Map}
-import gleam/result.{lazy_unwrap}
 import gleam/uri
 import gleam/hackney
-import gleam/option.{None, Some}
 import mist
 
-fn do_distlist(
+external type Index
-  b: String,
+external type Field
-  distlist: List(Int),
-  grapheme: String,
-  new_distlist: List(Int),
-  last_dist: Int,
-) {
-  case #(b, distlist) {
-    #("", _) -> list.reverse(new_distlist)
-    #(_, [distlist_hd, distlist_snd, ..distlist_tl]) -> {
-      let assert Ok(b_hd) = string.first(b)
-      let b_tl = string.drop_left(b, up_to: 1)
-      let diff = case #(b_hd, grapheme) {
-        #(a, b) if a != b -> 1
-        _ -> 0
-      }
-      let minimum =
-        int.min(int.min(last_dist + 1, distlist_snd + 1), distlist_hd + diff)
-      do_distlist(
-        b_tl,
-        [distlist_snd, ..distlist_tl],
-        grapheme,
-        [minimum, ..new_distlist],
-        minimum,
-      )
-    }
-  }
-}
 
-fn do_distance(a: String, b: String, distlist: List(Int), step: Int) {
+external fn index_new(atom.Atom) -> Index =
-  case a {
+  "Elixir.Haystack.Index" "new"
-    "" -> result.unwrap(list.last(distlist), -1)
-    _ -> {
-      let assert Ok(src_hd) = string.first(a)
-      let src_tl = string.drop_left(a, up_to: 1)
-      let distlist = do_distlist(b, distlist, src_hd, [step], step)
-      do_distance(src_tl, b, distlist, step + 1)
-    }
-  }
-}
 
-fn levenshtein(a: String, b: String) -> Int {
+external fn index_ref(Index, Field) -> Index =
-  case #(a, b) {
+  "Elixir.Haystack.Index" "ref"
-    #(a, b) if a == b -> 0
+
-    #("", b) -> string.length(b)
+external fn index_field(Index, Field) -> Index =
-    #(a, "") -> string.length(a)
+  "Elixir.Haystack.Index" "field"
-    #(a, b) -> {
+
-      let distlist = list.range(0, string.length(b))
+external fn field_term(String) -> Field =
-      do_distance(a, b, distlist, 1)
+  "Elixir.Haystack.Index.Field" "term"
-    }
+
-  }
+external fn field_new(String) -> Field =
-}
+  "Elixir.Haystack.Index.Field" "new"
+
+external fn index_add(Index, List(a)) -> Index =
+  "Elixir.Haystack.Index" "add"
+
+external fn index_search(Index, String) -> List(Map(atom.Atom, String)) =
+  "Elixir.Haystack.Index" "search"
+
+pub external fn inspect(a) -> a =
+  "Elixir.IO" "inspect"
+
+external type Query
+external type Clause
+external type Expression
+external fn query_new() -> Query =
+  "Elixir.Haystack.Query" "new"
+external fn query_clause(Query, Clause) -> Query =
+  "Elixir.Haystack.Query" "clause"
+external fn query_run(Query, Index) -> List(Map(atom.Atom, String)) =
+  "Elixir.Haystack.Query" "run"
+external fn clause_new(atom.Atom) -> Clause =
+  "Elixir.Haystack.Query.Clause" "new"
+external fn query_expressions(Clause, List(Expression)) -> Clause =
+  "Elixir.Haystack.Query.Clause" "expressions"
+external fn query_expression_new(atom.Atom, List(#(atom.Atom, String))) -> Expression =
+  "Elixir.Haystack.Query.Expression" "new"
+
+external fn tokenize(String) -> List(Map(atom.Atom, String)) =
+  "Elixir.Haystack.Tokenizer" "tokenize"
 
 fn unpercent(encoded: String) -> String {
   let #([head], chunks) =
@@ -94,34 +86,38 @@ fn unpercent(encoded: String) -> String {
   res
 }
 
-fn guess_station(query: String, stations: Map(String, String)) -> String {
-  query
-  stations
-  |> map.keys
-  |> list.map(fn(a) { #(levenshtein(query, a), a) })
-  |> list.fold(
-    from: #(string.length(query), query),
-    with: fn(a, b) {
-      case a.0 < b.0 {
-        True -> a
-        False -> b
-      }
-    },
-  )
-  |> fn(a: #(Int, String)) { a.1 }
-}
-
 fn the_lookup(
   query: String,
   stations: Map(String, String),
   ds100s: Map(String, String),
-) -> String {
+  fuzzy: fn(String) -> List(String)
-  map.get(ds100s, query)
+) -> #(Int, String) {
-  |> lazy_unwrap(fn() {
+  case map.get(ds100s, query) {
+    Ok(name) -> #(200, name)
+    _ -> {
       io.println(query)
-    map.get(stations, query)
+      case map.get(stations, query) {
-    |> lazy_unwrap(fn() { guess_station(query, stations) })
+        Ok(ds100) -> #(200, ds100)
-  })
+        _ -> {
+          let results = fuzzy(query)
+            |> list.filter_map(fn (res) { map.get(ds100s, string.uppercase(res)) })
+          case results {
+            // results -> {
+            //   let names = results
+            //     |> list.map (fn (res) {
+            //     map.get(ds100s, string.uppercase(res))
+            //     |> result.map(fn(a) { "/" <> a })
+            //     |> result.unwrap("/")})
+            //   #(200, string.join(names, "\n"))
+            // }
+            [res] -> #(302, res)
+            [res, ..] -> #(302, res)
+            _ -> #(404, "??")
+          }
+        }
+      }
+    }
+  }
 }
 
 fn lookup_station(
@@ -129,6 +125,7 @@ fn lookup_station(
   stations: Map(String, String),
   ds100s: Map(String, String),
   baseurl: String,
+  fuzzy: fn (String) -> List(String)
 ) -> Response(BitBuilder) {
   let #(code, text) = case request {
     Request(method: Get, path: "/help", ..)
@@ -136,10 +133,8 @@ fn lookup_station(
       200,
       "ds100 → Name: " <> baseurl <> "/NN\n" <> "Name → ds100: " <> baseurl <> "/Nürnberg Hbf",
     )
-    Request(method: Get, path: "/" <> path, ..) -> #(
+    Request(method: Get, path: "/" <> path, ..) ->
-      200,
+      the_lookup(unpercent(path), stations, ds100s, fuzzy)
-      the_lookup(unpercent(path), stations, ds100s),
-    )
     _ -> #(404, "intended usage is e.g. curl " <> baseurl <> "/FF")
   }
   let body = bit_builder.from_string(text)
@@ -154,6 +149,10 @@ fn lookup_station(
     "https://stuebinm.eu/git/bahnhof.name",
   )
   |> response.prepend_header("content-type", "text/plain; charset=utf8")
+  |> fn (a) { case code == 302 {
+        True -> response.prepend_header(a, "location", text)
+        _ -> a
+     } }
   |> response.set_body(body)
 }
 
@@ -193,10 +192,56 @@ pub fn main() {
     stations
     |> list.map(fn(a) { #(a.1, a.0) })
     |> map.from_list
+  let ref = atom.create_from_string("ref")
+  let index =  index_new(atom.create_from_string("stations"))
+    |> index_ref(field_term("id"))
+    |> index_field(field_new("name"))
+    |> index_add(stations
+        |> list.map(fn(tuple) {case tuple {
+          #(name, ds100)
+          -> map.from_list([#("id", ds100), #("name", name)]
+    )}}))
 
-  mist.run_service(
+
+  let fuzzy = fn(searchterm: String) -> List(String) {
+    let query = query_new()
+    let match = atom.create_from_string("match")
+    let field = atom.create_from_string("field")
+    let term = atom.create_from_string("term")
+    let expressions = tokenize(inspect(searchterm))
+      |> list.filter_map(fn (a) { map.get(a, atom.create_from_string("v")) })
+      |> list.map(fn (token) { query_expression_new(match, [#(field, "name"), #(term, token)]) })
+    let clause = query_expressions(clause_new(atom.create_from_string("all")), expressions)
+    let query = query_clause(query, clause)
+
+    let matches = query_run(query, index)
+      |> list.filter_map(fn (a) { map.get(a, ref) })
+
+    inspect(matches)
+    case list.length(matches) > 5 {
+      True -> {
+        let query = query_new()
+        let clause = query_expressions(
+          clause_new(atom.create_from_string("all")),
+          [query_expression_new(match, [#(field, "name"), #(term, "hbf")]) , ..expressions]
+        )
+        let query = query_clause(query, clause)
+        let narrow = query_run(query, index)
+          |> list.filter_map(fn (a) { map.get(a, ref) })
+        case narrow {
+          [] -> matches
+          _ -> narrow
+        }
+      }
+      _ -> matches
+    }
+  }
+
+  io.println("compiled index, starting server …")
+
+  let _ = mist.run_service(
     2345,
-    fn(req) { lookup_station(req, stationmap, ds100map, baseurl) },
+    fn(req) { lookup_station(req, stationmap, ds100map, baseurl, fuzzy) },
     max_body_limit: 100,
   )
   process.sleep_forever()