From 998e77fa69453e7d33bb313bdc80910aa4298e4a Mon Sep 17 00:00:00 2001
From: osmarks <osmarks@protonmail.com>
Date: Tue, 14 Aug 2018 21:16:27 +0100
Subject: [PATCH] Fuzzy search, more generalized result types

---
 backend-chests.lua |  8 +++---
 fuzzy.lua          | 66 ++++++++++++++++++++++++++++++++++++++++++++++
 lib.lua            | 16 +++++++----
 3 files changed, 80 insertions(+), 10 deletions(-)
 create mode 100644 fuzzy.lua

diff --git a/backend-chests.lua b/backend-chests.lua
index 1552972..ccb9787 100644
--- a/backend-chests.lua
+++ b/backend-chests.lua
@@ -3,6 +3,7 @@
 
 local w = require "lib"
 local d = require "luadash"
+local fuzzy_match = require "fuzzy"
 
 local conf = w.load_config({
     "buffer_internal",
@@ -96,12 +97,9 @@ local function find_by_ID_meta_NBT(ID, meta, NBT_hash)
 end
 
 local function search(query, threshold)
-    local threshold = threshold or 4
     local results = find(function(item)
-        local distance = d.distance(string.lower(query), string.lower(item.display_name))
-        if distance < threshold then
-            return true, distance
-        else return false end
+        local match, best_start = fuzzy_match(item.display_name, query)
+        if best_start ~= nil and match > 0 then return true, match end
     end)
     return d.sort_by(results, function(x) return x.extra end) -- sort returned results by closeness to query
 end
diff --git a/fuzzy.lua b/fuzzy.lua
new file mode 100644
index 0000000..fad3989
--- /dev/null
+++ b/fuzzy.lua
@@ -0,0 +1,66 @@
+-- Squid's fuzzy search thing
+-- https://github.com/SquidDev-CC/artist/blob/vnext/artist/lib/match.lua
+
+local score_weight = 1000
+
+local adjacency_bonus = 5
+
+local leading_letter_penalty = -3
+local leading_letter_penalty_max = -9
+local unmatched_letter_penalty = -1
+
+local function match_simple(str, ptrn)
+  local best_score, best_start = 0, nil
+
+  -- Trim the two strings
+  ptrn = ptrn:gsub("^ *", ""):gsub(" *$", "")
+  str = str:gsub("^ *", ""):gsub(" *$", "")
+
+  local str_lower = str:lower()
+  local ptrn_lower = ptrn:lower()
+
+  local start = 1
+  while true do
+    -- Find a location where the first character matches
+    start = str_lower:find(ptrn_lower:sub(1, 1), start, true)
+    if not start then break end
+
+    -- All letters before the current one are considered leading, so add them to our penalty
+    local score = score_weight + math.max(leading_letter_penalty * (start - 1), leading_letter_penalty_max)
+    local previous_match = true
+
+    -- We now walk through each pattern character and attempt to determine if they match
+    local str_pos, ptrn_pos = start + 1, 2
+    while str_pos <= #str and ptrn_pos <= #ptrn do
+      local ptrn_char = ptrn_lower:sub(ptrn_pos, ptrn_pos)
+      local str_char = str_lower:sub(str_pos, str_pos)
+
+      if ptrn_char == str_char then
+        -- If we've got multiple adjacent matches then give bonus points
+        if previous_match then score = score + adjacency_bonus end
+
+        previous_match = true
+        ptrn_pos = ptrn_pos + 1
+      else
+        -- If we don't match a letter then minus points
+        score = score + unmatched_letter_penalty
+
+        previous_match = false
+      end
+
+      str_pos = str_pos + 1
+    end
+
+    -- If we've matched the entire pattern then consider us as a candidate
+    if ptrn_pos > #ptrn and score > best_score then
+      best_score = score
+      best_start = start
+    end
+
+    start = start + 1
+  end
+
+  return best_score, best_start
+end
+
+return match_simple
\ No newline at end of file
diff --git a/lib.lua b/lib.lua
index ebdd0fe..a169332 100644
--- a/lib.lua
+++ b/lib.lua
@@ -126,7 +126,7 @@ local function serve(fn, node_type)
                 local end_time = os.clock()
                 print("Response:", textutils.serialise(result))
                 print("Time:", string.format("%.1f", end_time - start_time))
-                response = { type = "response", response = result }
+                response = { type = "OK", value = result }
             end
         else
             print("Request Invalid")
@@ -252,7 +252,7 @@ local function init()
     d.map(find_peripherals(function(type, name, wrapped) return type == "modem" end), function(p) rednet.open(p.name) end)
 end
 
--- Rust-style unwrap. If x is a response type, will take out its contents and return them - if error, will crash and print it, with msg if provided
+-- Rust-style unwrap. If x is an OK table, will take out its contents and return them - if error, will crash and print it, with msg if provided
 local function unwrap(x, msg)
     if not x or type(x) ~= "table" or not x.type then x = errors.make(errors.INTERNAL, "Error/response object is invalid. This is probably a problem with the node being contacted.") end
 
@@ -262,9 +262,15 @@ local function unwrap(x, msg)
         else text = text .. "!" end
         text = text .. ".\nDetails: " .. errors.format(x)
         error(text)
-    elseif x.type == "response" then
-        return x.response
+    elseif x.type == "OK" then
+        return x.value
     end
 end
 
-return { errors = errors, serve = serve, query_by_ID = query_by_ID, query_by_type = query_by_type, unwrap = unwrap, to_wyvern_item = to_wyvern_item, get_internal_identifier = get_internal_identifier, load_config = load_config, find_peripherals = find_peripherals, init = init, collate = collate, satisfied = satisfied, collate_stacks = collate_stacks }
+-- Wrap x in an OK result
+local function make_OK(x)
+    return { type = "OK", value = x }
+end
+
+-- TODO: Not do this
+return { errors = errors, serve = serve, query_by_ID = query_by_ID, query_by_type = query_by_type, unwrap = unwrap, to_wyvern_item = to_wyvern_item, get_internal_identifier = get_internal_identifier, load_config = load_config, find_peripherals = find_peripherals, init = init, collate = collate, satisfied = satisfied, collate_stacks = collate_stacks, make_error = errors.make, make_OK = make_OK }
\ No newline at end of file