local config = require("oil.config")
local fs = require("oil.fs")
local util = require("oil.util")

local M = {}

---@param filepath string
---@param pattern lsp.FileOperationPattern
---@return boolean
local function file_matches(filepath, pattern)
  local is_dir = vim.fn.isdirectory(filepath) == 1
  if pattern.matches then
    if (pattern.matches == "file" and is_dir) or (pattern.matches == "folder" and not is_dir) then
      return false
    end
  end

  if vim.lsp._watchfiles then
    local glob = pattern.glob
    local path = filepath
    if vim.tbl_get(pattern, "options", "ignoreCase") then
      glob, path = glob:lower(), path:lower()
    end
    return vim.lsp._watchfiles._match(glob, path)
  end

  local pat = vim.fn.glob2regpat(pattern.glob)
  if vim.tbl_get(pattern, "options", "ignoreCase") then
    pat = "\\c" .. pat
  end

  local ignorecase = vim.o.ignorecase
  vim.o.ignorecase = false
  local match = vim.fn.match(filepath, pat) >= 0
  vim.o.ignorecase = ignorecase
  return match
end

---@param filepath string
---@param filters lsp.FileOperationFilter[]
---@return boolean
local function any_match(filepath, filters)
  for _, filter in ipairs(filters) do
    local scheme_match = not filter.scheme or filter.scheme == "file"
    if scheme_match and file_matches(filepath, filter.pattern) then
      return true
    end
  end
  return false
end

---@return nil|{src: string, dest: string}
local function get_matching_paths(client, path_pairs)
  local filters =
    vim.tbl_get(client.server_capabilities, "workspace", "fileOperations", "willRename", "filters")
  if not filters then
    return nil
  end
  local ret = {}
  for _, pair in ipairs(path_pairs) do
    if fs.is_subpath(client.config.root_dir, pair.src) then
      local relative_file = pair.src:sub(client.config.root_dir:len() + 2)
      if any_match(pair.src, filters) or any_match(relative_file, filters) then
        table.insert(ret, pair)
      end
    end
  end
  if vim.tbl_isempty(ret) then
    return nil
  else
    return ret
  end
end

---@return table<number, {is_open: boolean, is_modified: boolean}>
local function get_buffers_status()
  local buffers_status = {}
  local buffers = vim.api.nvim_list_bufs()
  for _, bufnr in ipairs(buffers) do
    buffers_status[bufnr] = {
      is_modified = vim.bo[bufnr].modified,
    }
  end
  return buffers_status
end

---Process LSP rename in the background
---@param actions oil.MoveAction[]
M.will_rename_files = function(actions)
  local path_pairs = {}
  for _, action in ipairs(actions) do
    local _, src_path = util.parse_url(action.src_url)
    assert(src_path)
    local src_file = fs.posix_to_os_path(src_path)
    local _, dest_path = util.parse_url(action.dest_url)
    assert(dest_path)
    local dest_file = fs.posix_to_os_path(dest_path)
    table.insert(path_pairs, { src = src_file, dest = dest_file })
  end

  local clients = vim.lsp.get_active_clients()
  for _, client in ipairs(clients) do
    local matching_paths = get_matching_paths(client, path_pairs)
    if matching_paths then
      client.request("workspace/willRenameFiles", {
        files = vim.tbl_map(function(pair)
          return {
            oldUri = vim.uri_from_fname(pair.src),
            newUri = vim.uri_from_fname(pair.dest),
          }
        end, matching_paths),
      }, function(_, result)
        if result then
          local buffers_status = get_buffers_status()
          vim.lsp.util.apply_workspace_edit(result, client.offset_encoding)
          local autosave = config.lsp_rename_autosave
          if autosave == false then
            return
          end

          for uri in pairs(result.changes) do
            local bufnr = vim.uri_to_bufnr(uri)
            local is_open = buffers_status[bufnr] ~= nil
            local is_modified = is_open and buffers_status[bufnr].is_modified
            local should_save = autosave == true or (autosave == "unmodified" and not is_modified)
            if should_save then
              vim.api.nvim_buf_call(bufnr, function()
                vim.cmd.update()
              end)
              if not is_open then
                vim.api.nvim_buf_delete(bufnr, { force = true })
              end
            end
          end
        end
      end)
    end
  end
end

-- LSP types from core Neovim

---A filter to describe in which file operation requests or notifications
---the server is interested in receiving.
---
---@since 3.16.0
---@class lsp.FileOperationFilter
---A Uri scheme like `file` or `untitled`.
---@field scheme? string
---The actual file operation pattern.
---@field pattern lsp.FileOperationPattern

---A pattern to describe in which file operation requests or notifications
---the server is interested in receiving.
---
---@since 3.16.0
---@class lsp.FileOperationPattern
---The glob pattern to match. Glob patterns can have the following syntax:
---- `*` to match one or more characters in a path segment
---- `?` to match on one character in a path segment
---- `**` to match any number of path segments, including none
---- `{}` to group sub patterns into an OR expression. (e.g. `**​/*.{ts,js}` matches all TypeScript and JavaScript files)
---- `[]` to declare a range of characters to match in a path segment (e.g., `example.[0-9]` to match on `example.0`, `example.1`, …)
---- `[!...]` to negate a range of characters to match in a path segment (e.g., `example.[!0-9]` to match on `example.a`, `example.b`, but not `example.0`)
---@field glob string
---Whether to match files or folders with this pattern.
---
---Matches both if undefined.
---@field matches? lsp.FileOperationPatternKind
---Additional options used during matching.
---@field options? lsp.FileOperationPatternOptions

---A pattern kind describing if a glob pattern matches a file a folder or
---both.
---
---@since 3.16.0
---@alias lsp.FileOperationPatternKind
---| "file" # file
---| "folder" # folder

---Matching options for the file operation pattern.
---
---@since 3.16.0
---@class lsp.FileOperationPatternOptions
---The pattern should be matched ignoring casing.
---@field ignoreCase? boolean

return M