local icon = require 'std.icon'

local HELP_PATTERNS = { '^h$', '^he$', '^hel$', '^help$', '^h%s', '^help%s' }

local BORDER_HIGHLIGHT_MAP = {
  search_down = { border = 'CmdlineBorderSearch', corner = 'CmdlineBorderCornerSearch' },
  search_up = { border = 'CmdlineBorderSearch', corner = 'CmdlineBorderCornerSearch' },
  shell = { border = 'CmdlineBorderShell', corner = 'CmdlineBorderCornerShell' },
  help = { border = 'CmdlineBorderHelp', corner = 'CmdlineBorderCornerHelp' },
  lua = { border = 'CmdlineBorderLua', corner = 'CmdlineBorderCornerLua' },
  input = { border = 'CmdlineBorderInput', corner = 'CmdlineBorderCornerInput' },
  cmdline = { border = 'CmdlineBorderCmdline', corner = 'CmdlineBorderCornerCmdline' },
}

local ICON_HIGHLIGHT_MAP = {
  search_down = 'CmdlineIconSearch',
  search_up = 'CmdlineIconSearch',
  shell = 'CmdlineIconShell',
  help = 'CmdlineIconHelp',
  lua = 'CmdlineIconLua',
  input = 'CmdlineIconInput',
  cmdline = 'CmdlineIconCmdline',
}

return {
  detect = function(firstc, content, prompt)
    if prompt and prompt ~= '' then
      return { type = 'input', icon = icon.prompt_prefix, lang = nil }
    end
    if prompt == '' and firstc == '' then
      return { type = 'input', icon = icon.prompt_prefix, lang = nil }
    end
    if firstc == '/' then
      return { type = 'search_down', icon = icon.search, lang = 'regex' }
    end
    if firstc == '?' then
      return { type = 'search_up', icon = icon.search_up, lang = 'regex' }
    end
    if firstc == '!' or (firstc == ':' and content and content:match '^!') then
      return { type = 'shell', icon = icon.shell, lang = 'bash' }
    end
    if firstc == ':' and content then
      for _, pat in ipairs(HELP_PATTERNS) do
        if content:match(pat) then
          return { type = 'help', icon = icon.help, lang = nil }
        end
      end
      if content:match '^lua%s' or content:match '^lua$' or content:match '^=' then
        return { type = 'lua', icon = icon.vim, lang = 'lua' }
      end
      return { type = 'cmdline', icon = icon.command, lang = 'vim' }
    end
    return { type = 'cmdline', icon = icon.command, lang = 'vim' }
  end,

  border_highlight_map = BORDER_HIGHLIGHT_MAP,

  icon_highlight = function(type)
    return ICON_HIGHLIGHT_MAP[type] or 'CmdlineIconCmdline'
  end,

  winhighlight = function(type, base)
    local hl = BORDER_HIGHLIGHT_MAP[type] or BORDER_HIGHLIGHT_MAP.cmdline
    return string.format('Normal:%s,FloatBorder:%s,FloatBorderCorner:%s', base, hl.border, hl.corner)
  end,

  prompt_lines = function(prompt, max_width)
    if not prompt or prompt == '' then
      return {}
    end
    vim.validate('prompt', prompt, 'string')
    vim.validate('max_width', max_width, 'number')
    local lines = {}
    for line in (prompt .. '\n'):gmatch('([^\n]*)\n') do
      table.insert(lines, line)
    end
    if #lines > 0 and lines[#lines] == '' then
      table.remove(lines)
    end
    local result = {}
    for _, line in ipairs(lines) do
      if vim.fn.strdisplaywidth(line) <= max_width then
        table.insert(result, line)
      else
        local remaining = line
        while remaining ~= '' and vim.fn.strdisplaywidth(remaining) > max_width do
          local cutoff = 0
          for i = 1, #remaining do
            if vim.fn.strdisplaywidth(remaining:sub(1, i)) > max_width then
              cutoff = i - 1
              break
            end
          end
          if cutoff == 0 then
            cutoff = math.min(max_width, #remaining)
          end
          local chunk = remaining:sub(1, cutoff)
          local last_space = chunk:match '()%s[^%s]*$'
          if last_space and last_space > 1 then
            local ws = chunk:match '%s+[^%s]*$'
            cutoff = #chunk - #ws
            chunk = chunk:sub(1, cutoff):gsub('%s+$', '')
          end
          table.insert(result, chunk)
          remaining = remaining:sub(cutoff + 1):gsub('^%s+', '')
        end
        if remaining ~= '' then
          table.insert(result, remaining)
        end
      end
    end
    return result
  end,

  PROMPT_MAX_RATIO = 0.85,
}