local util = require("test-samurai.util")

local runner = {
  name = "lua-plenary",
  framework = "plenary",
}

local function is_lua_test_path(path)
  if not path or path == "" then
    return false
  end
  if not path:match("%.lua$") then
    return false
  end
  if path:match("_spec%.lua$") then
    return true
  end
  if path:match("/tests/") then
    return true
  end
  return false
end

function runner.is_test_file(bufnr)
  local path = util.get_buf_path(bufnr)
  return is_lua_test_path(path)
end

local function find_repo_root(file)
  local root = util.find_root(file, { ".git", "tests", "lua", "plugin" })
  if not root or root == "" then
    root = vim.loop.cwd()
  end
  return root
end

local function minimal_init_for(root)
  return vim.fs.joinpath(root, "tests", "minimal_init.lua")
end

local function escape_for_ex_double_quotes(s)
  s = s or ""
  s = s:gsub("\\", "\\\\")
  s = s:gsub('"', '\\"')
  return s
end

local function count_keyword(line, kw)
  local c = 0
  local pat = "%f[%w]" .. kw .. "%f[%W]"
  for _ in line:gmatch(pat) do
    c = c + 1
  end
  return c
end

local function find_end_lua_block(lines, start_idx)
  local depth = 0
  local started = false
  for i = start_idx, #lines do
    local line = lines[i]
    local fnc = count_keyword(line, "function")
    local endc = count_keyword(line, "end")
    if fnc > 0 then
      depth = depth + fnc
      started = true
    end
    if started and endc > 0 then
      depth = depth - endc
      if depth <= 0 then
        return i - 1
      end
    end
  end
  return #lines - 1
end

local function collect_lua_structs(lines)
  local describes = {}
  local tests = {}

  for i, line in ipairs(lines) do
    local dname = line:match("^%s*describe%s*%(%s*['\"`]([^'\"`]+)['\"`]")
    if dname then
      local start0 = i - 1
      local end0 = find_end_lua_block(lines, i)
      table.insert(describes, { kind = "describe", name = dname, start = start0, ["end"] = end0 })
    else
      local tname = line:match("^%s*it%s*%(%s*['\"`]([^'\"`]+)['\"`]")
      if tname then
        local start0 = i - 1
        local end0 = find_end_lua_block(lines, i)
        table.insert(tests, { kind = "it", name = tname, start = start0, ["end"] = end0 })
      end
    end
  end

  return describes, tests
end

local function build_full_name(lines, idx, leaf_name)
  local parts = { leaf_name }
  for i = idx - 1, 1, -1 do
    local line = lines[i]
    local dname = line:match("^%s*describe%s*%(%s*['\"`]([^'\"`]+)['\"`]")
    if dname then
      table.insert(parts, 1, dname)
    end
  end
  return table.concat(parts, " ")
end

function runner.find_nearest(bufnr, row, _col)
  if not runner.is_test_file(bufnr) then
    return nil, "not a lua test file"
  end

  local lines = util.get_buf_lines(bufnr)
  local describes, tests = collect_lua_structs(lines)

  for _, t in ipairs(tests) do
    if row >= t.start and row <= t["end"] then
      local full = build_full_name(lines, t.start + 1, t.name)
      local file = util.get_buf_path(bufnr)
      local root = find_repo_root(file)
      return { file = file, cwd = root, test_name = t.name, full_name = full, kind = "it" }
    end
  end

  local best_describe = nil
  for _, d in ipairs(describes) do
    if row >= d.start and row <= d["end"] then
      if not best_describe or d.start >= best_describe.start then
        best_describe = d
      end
    end
  end
  if best_describe then
    local full = build_full_name(lines, best_describe.start + 1, best_describe.name)
    local file = util.get_buf_path(bufnr)
    local root = find_repo_root(file)
    return { file = file, cwd = root, test_name = best_describe.name, full_name = full, kind = "describe" }
  end

  local start = row + 1
  if start > #lines then
    start = #lines
  elseif start < 1 then
    start = 1
  end
  for i = start, 1, -1 do
    local line = lines[i]
    local tname = line:match("^%s*it%s*%(%s*['\"`]([^'\"`]+)['\"`]")
    if tname then
      local full = build_full_name(lines, i, tname)
      local file = util.get_buf_path(bufnr)
      local root = find_repo_root(file)
      return { file = file, cwd = root, test_name = tname, full_name = full, kind = "it" }
    end
    local dname = line:match("^%s*describe%s*%(%s*['\"`]([^'\"`]+)['\"`]")
    if dname then
      local full = build_full_name(lines, i, dname)
      local file = util.get_buf_path(bufnr)
      local root = find_repo_root(file)
      return { file = file, cwd = root, test_name = dname, full_name = full, kind = "describe" }
    end
  end

  return nil, "no test call found"
end

local function ex_plenary_busted_file(file, filter_name)
  local ex = "PlenaryBustedFile " .. vim.fn.fnameescape(file)
  if filter_name and filter_name ~= "" then
    local f = escape_for_ex_double_quotes(filter_name)
    ex = ex .. ' { busted_args = { "--filter", "' .. f .. '" } }'
  end
  return ex
end

function runner.build_command(spec)
  local root = spec and spec.cwd or vim.loop.cwd()
  local minit = minimal_init_for(root)

  local cmd = {
    "nvim",
    "--headless",
    "-u",
    minit,
    "-c",
    ex_plenary_busted_file(spec.file, spec.test_name),
    "-c",
    "qa",
  }

  return { cmd = cmd, cwd = root }
end

function runner.build_file_command(bufnr)
  local file = util.get_buf_path(bufnr)
  if not file or file == "" then
    return nil
  end
  local root = find_repo_root(file)
  local minit = minimal_init_for(root)

  local cmd = {
    "nvim",
    "--headless",
    "-u",
    minit,
    "-c",
    ex_plenary_busted_file(file, nil),
    "-c",
    "qa",
  }

  return { cmd = cmd, cwd = root }
end

function runner.build_all_command(bufnr)
  local file = util.get_buf_path(bufnr)
  local root = find_repo_root(file)
  local minit = minimal_init_for(root)

  local cmd = {
    "nvim",
    "--headless",
    "-u",
    minit,
    "-c",
    "PlenaryBustedDirectory tests",
    "-c",
    "qa",
  }

  return { cmd = cmd, cwd = root }
end

return runner