-- Simple PDF viewer using pdftoppm + image.nvim
-- Requires: poppler (brew install poppler)

return {
  '3rd/image.nvim',
  config = function()
    local image = require('image')
    image.setup({})
    
    local pdf_state = {}
    
    vim.api.nvim_create_autocmd('BufReadPost', {
      pattern = '*.pdf',
      callback = function()
        local pdf_path = vim.fn.expand('%:p')
        local temp_dir = vim.fn.tempname()
        vim.fn.mkdir(temp_dir, 'p')
        local bufnr = vim.api.nvim_get_current_buf()
        
        -- Convert all pages upfront
        vim.notify('Converting PDF...', vim.log.levels.INFO)
        
        vim.fn.jobstart({
          'pdftoppm', '-png',
          pdf_path, temp_dir .. '/page'
        }, {
          on_exit = function(_, code)
            vim.schedule(function()
              if code ~= 0 then
                vim.notify('Failed to convert PDF', vim.log.levels.ERROR)
                return
              end
              
              -- Count generated files
              local handle = vim.loop.fs_scandir(temp_dir)
              local page_count = 0
              if handle then
                while true do
                  local name = vim.loop.fs_scandir_next(handle)
                  if not name then break end
                  if name:match('^page%-%d+%.png$') then
                    page_count = page_count + 1
                  end
                end
              end
              
              pdf_state[bufnr] = {
                temp_dir = temp_dir,
                current_page = 1,
                total_pages = page_count,
              }
              
              local function show_page(page_num)
                local state = pdf_state[bufnr]
                if not state then return end
                
                image.clear()
                
                vim.bo[bufnr].modifiable = true
                vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, {''})
                vim.bo[bufnr].modifiable = false
                
                local page_file = string.format('%s/page-%02d.png', state.temp_dir, page_num)
                local img = image.from_file(page_file, { buffer = bufnr })
                
                if img then
                  img:render()
                  vim.notify(string.format('Page %d / %d', page_num, state.total_pages), vim.log.levels.INFO)
                else
                  vim.notify('Failed to load page ' .. page_num, vim.log.levels.ERROR)
                end
              end
              
              local function change_page(delta)
                local state = pdf_state[bufnr]
                if not state then return end
                
                local new_page = state.current_page + delta
                if new_page < 1 or new_page > state.total_pages then
                  return
                end
                
                state.current_page = new_page
                show_page(new_page)
              end
              
              -- Keymaps
              vim.keymap.set('n', 'j', function() change_page(1) end, { buffer = bufnr, desc = 'Next page' })
              vim.keymap.set('n', 'k', function() change_page(-1) end, { buffer = bufnr, desc = 'Previous page' })
              vim.keymap.set('n', '<Right>', function() change_page(1) end, { buffer = bufnr, desc = 'Next page' })
              vim.keymap.set('n', '<Left>', function() change_page(-1) end, { buffer = bufnr, desc = 'Previous page' })
              vim.keymap.set('n', 'q', '<cmd>bd!<cr>', { buffer = bufnr, silent = true })
              
              -- Show first page
              show_page(1)
            end)
          end
        })
      end,
    })
    
    -- Cleanup
    vim.api.nvim_create_autocmd('BufDelete', {
      pattern = '*.pdf',
      callback = function(args)
        if pdf_state[args.buf] then
          image.clear()
          vim.fn.delete(pdf_state[args.buf].temp_dir, 'rf')
          pdf_state[args.buf] = nil
        end
      end,
    })
  end,
}