#!/usr/libexec/flua

--[[
SPDX-License-Identifier: BSD-2-Clause-FreeBSD

Copyright (c) 2022 Stefan Esser <se@FreeBSD.org>

Generate a list of existing and required CONFLICTS_INSTALL lines
for all ports (limited to ports for which official packages are
provided).

This script depends on the ports-mgmt/pkg-provides port for the list
of files installed by all pre-built packages for the architecture
the script is run on.

The script generates a list of ports by running "pkg provides ." and
a mapping from package base name to origin via "pkg rquery '%n %o'".

The existing CONFLICTS and CONFLICTS_INSTALL definitions are fetched
by "make -C $origin -V CONFLICTS -V CONFLICTS_INSTALL". This list is
only representative for the options configured for each port (i.e.
if non-default options have been selected and registered, these may
lead to a non-default list of conflicts).

The script detects files used by more than one port, than lists by
origin the existing definition and the list of package base names
that have been detected to cause install conflicts followed by the
list of duplicate files separated by a hash character "#".

This script uses the "hidden" LUA interpreter in the FreeBSD base
systems and does not need any port except "pkg-provides" to be run.

The run-time on my system checking the ~32000 packages available
for -CURRENT on amd64 is less than 250 seconds.

Example output:

# Port:  games/sol
# Files: bin/sol
# <      aisleriot gnome-games
# >      aisleriot
portedit merge -ie 'CONFLICTS_INSTALL=aisleriot # bin/sol' /usr/ports/games/sol

The output is per port (for all flavors of the port, if applicable),
gives examples of conflicting files (mostly to understand whether
different versions of a port could co-exist), the current CONFLICTS
and CONFLICTS_INSTALL entries merged, and a suggested new entry.
This information is followed by a portedit command line that should
do the right thing for simple cases, but the result should always
be checked before the resulting Makefile is committed.
--]]

require "lfs"

-------------------------------------------------------------------
local function table_sorted_keys(t)
   local result = {}
   for k, _ in pairs(t) do
      result[#result + 1] = k
   end
   table.sort(result)
   return result
end

local function table_sort_uniq(t)
   local result = {}
   if t then
      local last
      table.sort(t)
      for _, entry in ipairs(t) do
         if entry ~= last then
            last = entry
            result[#result + 1] = entry
         end
      end
   end
   return result
end

local function fnmatch(name, pattern)
   local function fnsubst(s)
      s = string.gsub(s, "%%", "%%%%")
      s = string.gsub(s, "%+", "%%+")
      s = string.gsub(s, "%-", "%%-")
      s = string.gsub(s, "%.", "%%.")
      s = string.gsub(s, "%?", ".")
      s = string.gsub(s, "%*", ".*")
      return s
   end
   local rexpr = ""
   local left, middle, right
   while true do
      left, middle, right = string.match(pattern, "([^[]*)(%[[^]]+%])(.*)")
      if not left then
         break
      end
      rexpr = rexpr .. fnsubst(left) .. middle
      pattern = right
   end
   rexpr = "^" .. rexpr .. fnsubst(pattern) .. "$"
   return string.find(name, rexpr)
end

-------------------------------------------------------------------
local function fetch_pkgs_origin()
   local pkgs = {}
   local pipe = io.popen("pkg rquery '%n %o'")
   for line in pipe:lines() do
      local pkgbase, origin = string.match(line, "(%S+) (%S+)")
      pkgs[origin] = pkgbase
   end
   pipe:close()
   pipe = io.popen("pkg rquery '%n %o %At %Av'")
   for line in pipe:lines() do
      local pkgbase, origin, tag, value = string.match(line, "(%S+) (%S+) (%S+) (%S+)")
      if tag == "flavor" then
         pkgs[origin] = nil
         pkgs[origin .. "@" .. value] = pkgbase
      end
   end
   pipe:close()
   return pkgs
end

-------------------------------------------------------------------
local function read_files(pattern)
   local files_table = {}
   local pkgbase
   local pipe = io.popen("pkg provides " .. pattern)
   for line in pipe:lines() do
      local label = string.sub(line, 1, 10)
      if label == "Name    : " then
	      local name = string.sub(line, 11)
	      pkgbase = string.match(name, "(.*)-[^-]*")
      elseif label == "          " or label == "Filename: " then
	      local file = string.sub(line, 11)
	      if file:sub(1, 10) == "usr/local/" then
            file = file:sub(11)
         else
            file = "/" .. file
         end
         local t = files_table[file] or {}
         t[#t + 1] = pkgbase
         files_table[file] = t
      end
   end
   pipe:close()
   return files_table
end

-------------------------------------------------------------------

local function fetch_pkg_pairs(pattern)
   local pkg_pairs = {}
   for file, pkgbases in pairs(read_files(pattern)) do
      if #pkgbases >= 2 then
         for i = 1, #pkgbases -1 do
            local pkg_i = pkgbases[i]
            for j = i + 1, #pkgbases do
               local pkg_j = pkgbases[j]
               if pkg_i ~= pkg_j then
                  local p1 = pkg_pairs[pkg_i] or {}
                  local p2 = p1[pkg_j] or {}
                  p2[#p2 + 1] = file
                  p1[pkg_j] = p2
                  pkg_pairs[pkg_i] = p1
               end
            end
         end
      end
   end
   return pkg_pairs
end

-------------------------------------------------------------------
local function conflicts_delta(old, new)
   local old_seen = {}
   local changed
   for i = 1, #new do
      local matched
      for j = 1, #old do
         if fnmatch(new[i], old[j]) then
            new[i] = old[j]
            old_seen[j] = true
            matched = true
            break
         end
      end
      changed = changed or not matched
   end
   if not changed then
      for j = 1, #old do
         if not old_seen[j] then
            changed = true
            break
         end
      end
   end
   if changed then
      return table_sort_uniq(new)
   end
end

-------------------------------------------------------------------
local function fetch_port_conflicts(origin)
   local dir, flavor = origin:match("([^@]+)@?(.*)")
   if flavor ~= "" then
      flavor = " FLAVOR=" .. flavor
   end
   local seen = {}
   local pipe = io.popen("make -C /usr/ports/" .. dir .. flavor .. " -V CONFLICTS -V CONFLICTS_INSTALL 2>/dev/null")
   for line in pipe:lines() do
      for word in line:gmatch("(%S+)%s?") do
         seen[word] = true
      end
   end
   pipe:close()
   return table_sorted_keys(seen)
end

-------------------------------------------------------------------
local function conflicting_pkgs(conflicting)
   local pkgs = {}
   for origin, pkgbase in pairs(fetch_pkgs_origin()) do
      if conflicting[pkgbase] then
         pkgs[origin] = pkgbase
      end
   end
   return pkgs
end

-------------------------------------------------------------------
local function collect_conflicts(pkg_pairs)
   local pkgs = {}
   local files = {}
   for pkg_i, p1 in pairs(pkg_pairs) do
      for pkg_j, p2 in pairs(p1) do
         pkgs[pkg_i] = pkgs[pkg_i] or {}
         pkgs[pkg_j] = pkgs[pkg_j] or {}
         table.insert(pkgs[pkg_i], pkg_j)
         table.insert(pkgs[pkg_j], pkg_i)
         files[pkg_i] = files[pkg_i] or {}
         files[pkg_j] = files[pkg_j] or {}
         for _, file in ipairs(p2) do
            table.insert(files[pkg_i], file)
            table.insert(files[pkg_j], file)
         end
      end
   end
   return pkgs, files
end

-------------------------------------------------------------------
local function split_origins(origin_list)
   local port_list = {}
   local flavors = {}
   local last_port
   for _, origin in ipairs(origin_list) do
      local port, flavor = string.match(origin, "([^@]+)@?(.*)")
      if port ~= last_port then
         port_list[#port_list + 1] = port
         if flavor ~= "" then
            flavors[port] = {flavor}
         end
      else
         table.insert(flavors[port], flavor)
      end
      last_port = port
   end
   return port_list, flavors
end

-------------------------------------------------------------------
-- TODO: Collect FLAVORs and report for port directory

local function merge_table(t1, t2)
   table.move(t2, 1, #t2, #t1 + 1, t1)
end

local PKG_PAIR_FILES = fetch_pkg_pairs(".")
local CONFLICT_PKGS = collect_conflicts(PKG_PAIR_FILES)
local PKGBASE = conflicting_pkgs(CONFLICT_PKGS)
local ORIGIN_LIST = table_sorted_keys(PKGBASE)
local PORT_LIST, FLAVORS = split_origins(ORIGIN_LIST)

local function conflicting_files(pkg_i, pkgs)
   local files = {}
   local f
   local p1 = PKG_PAIR_FILES[pkg_i]
   if p1 then
      for _, pkg_j in ipairs(pkgs) do
         f = p1[pkg_j]
         if f then
            table.sort(f)
            files[#files + 1] = f[1]
         end
      end
   end
   for _, pkg_j in ipairs(pkgs) do
      p1 = PKG_PAIR_FILES[pkg_j]
      f = p1 and p1[pkg_i]
      if f then
         table.sort(f)
         files[#files + 1] = f[1]
      end
   end
   return files
end

for _, port in ipairs(PORT_LIST) do
   local port_conflicts = {}
   local files = {}
   local conflict_pkgs = {}
   local function merge_data(origin)
      local pkgbase = PKGBASE[origin]
      merge_table(files, conflicting_files(pkgbase, CONFLICT_PKGS[pkgbase]))
      merge_table(conflict_pkgs, CONFLICT_PKGS[pkgbase])
      merge_table(port_conflicts, fetch_port_conflicts(origin))
   end
   local flavors = FLAVORS[port]
   if flavors then
      for _, flavor in ipairs(flavors) do
         merge_data(port .. "@" .. flavor)
      end
   else
      merge_data(port)
   end
   local conflicts_new = table_sort_uniq(conflict_pkgs)
   if #port_conflicts then
      port_conflicts = table_sort_uniq(port_conflicts)
      conflicts_new = conflicts_delta(port_conflicts, conflicts_new)
   end
   if conflicts_new then
      local conflicts_string = table.concat(port_conflicts, " ")
      local conflicts_string_new = table.concat(conflicts_new, " ")
      local file_list = table.concat(table_sort_uniq(files), " ")
      print("# Port:  " .. port)
      print("# Files: " .. file_list)
      if conflicts_string ~= "" then
         print("# <      " .. conflicts_string)
      end
      print("# >      " .. conflicts_string_new)
      print("portedit merge -ie 'CONFLICTS_INSTALL=" .. conflicts_string_new .. " # " .. file_list .. "' /usr/ports/" .. port)
      print()
   end
end