local M = {}

---@param stderr string
---@return preview.Diagnostic[]
local function parse_typst(stderr)
  local diagnostics = {}
  for line in stderr:gmatch('[^\r\n]+') do
    local file, lnum, col, severity, msg = line:match('^(.+):(%d+):(%d+): (%w+): (.+)$')
    if lnum then
      local sev = vim.diagnostic.severity.ERROR
      if severity == 'warning' then
        sev = vim.diagnostic.severity.WARN
      end
      table.insert(diagnostics, {
        lnum = tonumber(lnum) - 1,
        col = tonumber(col) - 1,
        message = msg,
        severity = sev,
        source = file,
      })
    end
  end
  return diagnostics
end

---@param stderr string
---@return preview.Diagnostic[]
local function parse_latexmk(stderr)
  local diagnostics = {}
  for line in stderr:gmatch('[^\r\n]+') do
    local _, lnum, msg = line:match('^%.?/?(.+%.tex):(%d+): (.+)$')
    if lnum then
      table.insert(diagnostics, {
        lnum = tonumber(lnum) - 1,
        col = 0,
        message = msg,
        severity = vim.diagnostic.severity.ERROR,
      })
    else
      local rule_msg = line:match('^%s+(%S.+gave return code %d+)$')
      if rule_msg then
        table.insert(diagnostics, {
          lnum = 0,
          col = 0,
          message = rule_msg,
          severity = vim.diagnostic.severity.ERROR,
        })
      end
    end
  end
  return diagnostics
end

---@param stderr string
---@return preview.Diagnostic[]
local function parse_pandoc(stderr)
  local diagnostics = {}
  for line in stderr:gmatch('[^\r\n]+') do
    local lnum, col, msg = line:match('Error at .+ %(line (%d+), column (%d+)%): (.+)$')
    if lnum then
      table.insert(diagnostics, {
        lnum = tonumber(lnum) - 1,
        col = tonumber(col) - 1,
        message = msg,
        severity = vim.diagnostic.severity.ERROR,
      })
    else
      local ylnum, ycol, ymsg =
        line:match('YAML parse exception at line (%d+), column (%d+)[,:]%s*(.+)$')
      if ylnum then
        table.insert(diagnostics, {
          lnum = tonumber(ylnum) - 1,
          col = tonumber(ycol) - 1,
          message = ymsg,
          severity = vim.diagnostic.severity.ERROR,
        })
      else
        local errmsg = line:match('^pandoc: (.+)$')
        if errmsg and not errmsg:match('^Error at') then
          table.insert(diagnostics, {
            lnum = 0,
            col = 0,
            message = errmsg,
            severity = vim.diagnostic.severity.ERROR,
          })
        end
      end
    end
  end
  return diagnostics
end

---@type preview.ProviderConfig
M.typst = {
  ft = 'typst',
  cmd = { 'typst', 'compile' },
  args = function(ctx)
    return { '--diagnostic-format', 'short', ctx.file }
  end,
  output = function(ctx)
    return (ctx.file:gsub('%.typ$', '.pdf'))
  end,
  error_parser = function(stderr)
    return parse_typst(stderr)
  end,
  open = { 'xdg-open' },
}

---@type preview.ProviderConfig
M.latex = {
  ft = 'tex',
  cmd = { 'latexmk' },
  args = function(ctx)
    return {
      '-pdf',
      '-interaction=nonstopmode',
      '-pdflatex=pdflatex -file-line-error -interaction=nonstopmode %O %S',
      ctx.file,
    }
  end,
  output = function(ctx)
    return (ctx.file:gsub('%.tex$', '.pdf'))
  end,
  error_parser = function(stderr)
    return parse_latexmk(stderr)
  end,
  clean = function(ctx)
    return { 'latexmk', '-c', ctx.file }
  end,
  open = { 'xdg-open' },
}

---@type preview.ProviderConfig
M.markdown = {
  ft = 'markdown',
  cmd = { 'pandoc' },
  args = function(ctx)
    local output = ctx.file:gsub('%.md$', '.html')
    return { ctx.file, '-s', '--embed-resources', '-o', output }
  end,
  output = function(ctx)
    return (ctx.file:gsub('%.md$', '.html'))
  end,
  error_parser = function(stderr)
    return parse_pandoc(stderr)
  end,
  clean = function(ctx)
    return { 'rm', '-f', (ctx.file:gsub('%.md$', '.html')) }
  end,
  open = { 'xdg-open' },
}

---@type preview.ProviderConfig
M.github = {
  ft = 'markdown',
  cmd = { 'pandoc' },
  args = function(ctx)
    local output = ctx.file:gsub('%.md$', '.html')
    return {
      '-f',
      'gfm',
      ctx.file,
      '-s',
      '--embed-resources',
      '--css',
      'https://cdn.jsdelivr.net/gh/pixelbrackets/gfm-stylesheet@master/dist/gfm.css',
      '-o',
      output,
    }
  end,
  output = function(ctx)
    return (ctx.file:gsub('%.md$', '.html'))
  end,
  error_parser = function(stderr)
    return parse_pandoc(stderr)
  end,
  clean = function(ctx)
    return { 'rm', '-f', (ctx.file:gsub('%.md$', '.html')) }
  end,
  open = { 'xdg-open' },
}

return M