From 06b29db64581124453d4db05fcfea91ddb5a46e6 Mon Sep 17 00:00:00 2001
From: ViViDboarder <ViViDboarder@gmail.com>
Date: Thu, 6 Jan 2022 21:14:18 -0800
Subject: [PATCH] Add new function for mapping versoins to last supported
 commits

---
 neovim/lua/plugins.lua | 27 ++++++--------
 neovim/lua/utils.lua   | 84 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 95 insertions(+), 16 deletions(-)

diff --git a/neovim/lua/plugins.lua b/neovim/lua/plugins.lua
index 9237da3..550838f 100644
--- a/neovim/lua/plugins.lua
+++ b/neovim/lua/plugins.lua
@@ -1,4 +1,5 @@
 -- Install packer
+local utils = require("utils")
 local install_path = vim.fn.stdpath("data") .. "/site/pack/packer/opt/packer.nvim"
 local packer_bootstrap = false
 if vim.fn.empty(vim.fn.glob(install_path)) > 0 then
@@ -16,20 +17,6 @@ local function config_dark_notify()
     })
 end
 
--- Pin version dependent packages due to unstable APIs
-local pinned_commits = {}
-if vim.fn.has("nvim-0.6.0") ~= 1 then
-    if vim.fn.has("nvim-0.5.1") == 1 then
-        -- Last commit compatible with 0.5.1
-        pinned_commits["telescope"] = "80cdb00b221f69348afc4fb4b701f51eb8dd3120"
-        pinned_commits["null-ls"] = "739a98c12bedaa2430c4a3c08d1d22ad6c16513e"
-    elseif vim.fn.has("nvim-0.5.0") == 1 then
-        -- Last commit compatible with 0.5.0
-        pinned_commits["telescope"] = "587a10d1494d8ffa1229246228f0655db2f0a48a"
-        pinned_commits["null-ls"] = "3e7390735501d0507bf2c2b5c2e7a16f58deeb81"
-    end
-end
-
 return require("packer").startup({
     function(use)
         -- Load things faster!
@@ -214,7 +201,11 @@ return require("packer").startup({
         -- Generic linter/formatters in diagnostics API
         use({
             "jose-elias-alvarez/null-ls.nvim",
-            commit = pinned_commits["null-ls"],
+            commit = utils.map_version_rule({
+                [">=0.6.0"] = nil,
+                [">=0.5.1"] = "739a98c12bedaa2430c4a3c08d1d22ad6c16513e",
+                [">=0.5.0"] = "3e7390735501d0507bf2c2b5c2e7a16f58deeb81",
+            }),
             requires = { "nvim-lua/plenary.nvim", "neovim/nvim-lspconfig" },
         })
 
@@ -289,7 +280,11 @@ return require("packer").startup({
                 "nvim-lua/plenary.nvim",
                 "nvim-lua/popup.nvim",
             },
-            commit = pinned_commits["telescope"],
+            commit = utils.map_version_rule({
+                [">=0.6.0"] = nil,
+                [">=0.5.1"] = "80cdb00b221f69348afc4fb4b701f51eb8dd3120",
+                [">=0.5.0"] = "587a10d1494d8ffa1229246228f0655db2f0a48a",
+            }),
             config = function()
                 require("plugins.telescope")
             end,
diff --git a/neovim/lua/utils.lua b/neovim/lua/utils.lua
index 6eab2fe..4366851 100644
--- a/neovim/lua/utils.lua
+++ b/neovim/lua/utils.lua
@@ -116,4 +116,88 @@ function M.try_require(name, on_found, on_notfound)
     end
 end
 
+-- Compare sequenced integers used to compare versions. Eg {0, 6, 0}
+function M.cmp_versions(a, b)
+    for i, part_a in pairs(a) do
+        local part_b = b[i]
+        if part_b == nil or part_a > part_b then
+            return 1
+        elseif part_a < part_b then
+            return -1
+        end
+    end
+
+    return 0
+end
+
+-- Checks if a list contains a value
+function M.list_contains(list, value)
+    for _, v in pairs(list) do
+        if v == value then
+            return true
+        end
+    end
+    return false
+end
+
+-- Materializes an iterator into a list
+function M.materialize_list(list, iterator)
+    if iterator == nil then
+        iterator = list
+        list = {}
+    end
+    for item in iterator do
+        table.insert(list, item)
+    end
+
+    return list
+end
+
+-- Maps a set of version rules to a value eg. [">0.5.0"] = "has 0.5.0"
+-- If more than one rule matches, the one with the greatest version number is used
+function M.map_version_rule(rules)
+    local v = vim.version()
+    local current_version = { v.major, v.minor, v.patch }
+
+    -- Parse a constraint and version of a string
+    local parse_rule = function(rule_string)
+        local cmp, major, minor, patch = string.gmatch(rule_string, "([=<>]+)(%d+).(%d+).(%d+)")()
+        return cmp, tonumber(major), tonumber(minor), tonumber(patch)
+    end
+
+    -- Checks if a constraint matches the current nvim instance
+    local matches = function(cmp, major, minor, patch)
+        local c = M.cmp_versions(current_version, { major, minor, patch })
+        if c == 1 then
+            if M.list_contains({ ">", ">=" }, cmp) then
+                return true
+            end
+        elseif c == 0 then
+            if M.list_contains({ "==", ">=", "<=" }, cmp) then
+                return true
+            end
+        elseif c == -1 then
+            if M.list_contains({ "<", "<=" }, cmp) then
+                return true
+            end
+        end
+        return false
+    end
+
+    local latest_version, latest_value = nil, nil
+    for rule, value in pairs(rules) do
+        local cmp, major, minor, patch = parse_rule(rule)
+        if matches(cmp, major, minor, patch) then
+            -- If the rule matches and the version that it matches is greater than the previous matches, save it
+            if latest_version == nil or M.cmp_versions({ major, minor, patch }, latest_version) == 1 then
+                latest_version = { major, minor, patch }
+                latest_value = value
+            end
+        end
+    end
+
+    -- Return highest versioned matched value
+    return latest_value
+end
+
 return M