feat(linter): add json parsing

lua/lsp/linter.lua

@@ -19,18 +19,143 @@ M.__index = M
 ---| "source"
 ---| "code"
 
+---@class JsonConfig
+---@field diagnostics_root? string
+---@field lnum? string
+---@field end_lnum? string
+---@field col? string
+---@field end_col? string
+---@field severity? string
+---@field message? string
+---@field source? string
+---@field code? string
+---@field zero_idx? boolean
+---@field callback? fun(diag: vim.Diagnostic)
+
 ---@class LinterConfig
 ---@field cmd string[]
 ---@field stdin? boolean
 ---@field stdout? boolean
 ---@field stderr? boolean
----@field pattern string
+---@field pattern? string
----@field groups Group[]
+---@field groups? Group[]
----@field severity_map table<string, vim.diagnostic.Severity>
+---@field severity_map? table<string, vim.diagnostic.Severity>
 ---@field source? string
 ---@field debounce? number
+---@field json? JsonConfig
 M.config = {}
 
+-- Extract a value from a JSON object using a path
+---@param obj table The JSON object
+---@param path string Path to the value (dot notation string)
+---@return any The value at the specified path, or nil if not found
+function M.get_json_value(obj, path)
+    if not obj then
+        return nil
+    end
+
+    local current = obj
+    local parts = {}
+
+    for part in path:gmatch("[^%.]+") do
+        table.insert(parts, part)
+    end
+
+    for _, key in ipairs(parts) do
+        if tonumber(key) ~= nil then
+            key = tonumber(key)
+        end
+
+        if type(current) ~= "table" then
+            return nil
+        end
+
+        current = current[key]
+        if current == nil then
+            return nil
+        end
+    end
+
+    return current
+end
+
+function M:process_json_output(json, bufnr)
+    local diagnostics = {}
+
+    local items = json
+    if self.config.json.diagnostics_root then
+        items = M.get_json_value(json, self.config.json.diagnostics_root)
+    end
+
+    if type(items) ~= "table" then
+        utils.err("diagnostics root is not an array or object")
+        return
+    end
+
+    if not vim.islist(items) then
+        items = { items }
+    end
+
+    for _, item in ipairs(items) do
+        local diag = {}
+
+        for field, path in pairs(self.config.json) do
+            if field ~= "diagnostics_root" and field ~= "callback" then
+                diag[field] = M.get_json_value(item, path)
+            end
+        end
+
+        diag.source = diag.source or self.config.source
+
+        if
+            diag.severity
+            and self.config.severity_map
+            and self.config.severity_map[diag.severity]
+        then
+            diag.severity = self.config.severity_map[diag.severity]
+        end
+
+        if not self.config.json.zero_idx then
+            if diag.lnum then
+                diag.lnum = diag.lnum - 1
+            end
+
+            if diag.end_lnum then
+                diag.end_lnum = diag.end_lnum - 1
+            end
+
+            if diag.col then
+                diag.col = diag.col - 1
+            end
+
+            if diag.end_col then
+                diag.end_col = diag.end_col - 1
+            end
+        end
+
+        if diag.end_lnum and diag.end_col then
+            local lines = vim.api.nvim_buf_get_lines(
+                bufnr,
+                diag.end_lnum,
+                diag.end_lnum + 1,
+                false
+            )
+
+            if #lines > 0 and #lines[1] > 0 then
+                diag.end_col = math.min(diag.end_col, #lines[1] - 1)
+            end
+        end
+
+        if type(self.config.json.callback) == "function" then
+            self.config.json.callback(diag)
+        end
+
+        table.insert(diagnostics, diag)
+    end
+
+    return diagnostics
+end
+
 function M.validate(name, config)
     local ok, resp = pcall(vim.validate, {
         name = { name, "string" },
@@ -49,12 +174,13 @@ function M.validate(name, config)
             stdin = { config.stdin, "boolean", true },
             stdout = { config.stdout, "boolean", true },
             stderr = { config.stderr, "boolean", true },
-            pattern = { config.pattern, "string" },
+            pattern = { config.pattern, "string", true },
             groups = {
                 config.groups,
                 function(t)
                     return utils.is_list(t, "string")
                 end,
+                true,
                 "list of strings",
             },
             severity_map = {
@@ -62,10 +188,12 @@ function M.validate(name, config)
                 function(t)
                     return utils.is_map(t, "string", "number")
                 end,
+                true,
                 "map of string and number",
             },
             debounce = { config.debounce, "number", true },
             source = { config.source, "string", true },
+            json = { config.json, "table", true },
         })
     end
 
@@ -74,11 +202,17 @@ function M.validate(name, config)
         return false
     end
 
+    if not config.json and (not config.pattern or not config.groups) then
+        utils.err("Either json or pattern and groups must be provided")
+        return false
+    end
+
     return true
 end
 
 function M:run(bufnr)
     local input
+
     -- TODO: add placeholder variables for when not using stdin
     if self.config.stdin then
         input = vim.api.nvim_buf_get_lines(bufnr, 0, -1, false)
@@ -88,13 +222,37 @@ function M:run(bufnr)
         vim.system,
         self.config.cmd,
         { stdin = input },
+        ---@param out vim.SystemCompleted
         vim.schedule_wrap(function(out)
             local output
+
             if self.config.stdout then
                 output = out.stdout or ""
             end
+
             if self.config.stderr then
                 output = out.stderr or ""
+            elseif out.stderr and out.stderr ~= "" then
+                utils.err(out.stderr)
+            end
+
+            if self.config.json then
+                local ok, json = pcall(
+                    vim.json.decode,
+                    output,
+                    { luanil = { object = true, array = true } }
+                )
+                if not ok then
+                    utils.err("Failed to parse JSON: " .. json)
+                    return
+                end
+
+                local diagnostics = self:process_json_output(json, bufnr)
+                if diagnostics then
+                    vim.diagnostic.set(self.namespace, bufnr, diagnostics)
+                end
+
+                return
             end
 
             local output_lines = vim.fn.split(output, "\n", false)
@@ -107,11 +265,24 @@ function M:run(bufnr)
                     self.config.groups,
                     self.config.severity_map
                 )
+
                 if not ok then
                     utils.err(tostring(resp))
                     return
                 elseif resp then
                     resp.source = resp.source or self.config.source
+
+                    local lines = vim.api.nvim_buf_get_lines(
+                        bufnr,
+                        resp.end_lnum,
+                        resp.end_lnum + 1,
+                        false
+                    )
+
+                    if #lines > 0 and #lines[1] > 0 then
+                        resp.end_col = math.min(resp.end_col, #lines[1] - 1)
+                    end
+
                     table.insert(diagnostics, resp)
                 end
             end