---@mod codetyper.parser Parser for /@ @/ prompt tags

local M = {}

local utils = require("codetyper.support.utils")
local logger = require("codetyper.support.logger")
local get_config = require("codetyper.utils.get_config").get_config
local find_prompts = require("codetyper.parser.find_prompts")

--- Find prompts in a buffer
---@param bufnr number Buffer number
---@return CoderPrompt[] List of found prompts
function M.find_prompts_in_buffer(bufnr)
  logger.func_entry("parser", "find_prompts_in_buffer", { bufnr = bufnr })

  local lines = vim.api.nvim_buf_get_lines(bufnr, 0, -1, false)
  local content = table.concat(lines, "\n")

  logger.debug(
    "parser",
    "find_prompts_in_buffer: bufnr=" .. bufnr .. ", lines=" .. #lines .. ", content_length=" .. #content
  )

  local cfg = get_config()
  local result = find_prompts(content, cfg.patterns.open_tag, cfg.patterns.close_tag)

  logger.func_exit("parser", "find_prompts_in_buffer", "found " .. #result .. " prompts")
  return result
end

--- Get prompt at cursor position
---@param bufnr? number Buffer number (default: current)
---@return CoderPrompt|nil Prompt at cursor or nil
function M.get_prompt_at_cursor(bufnr)
  bufnr = bufnr or vim.api.nvim_get_current_buf()
  local cursor = vim.api.nvim_win_get_cursor(0)
  local line = cursor[1]
  local col = cursor[2] + 1 -- Convert to 1-indexed

  logger.func_entry("parser", "get_prompt_at_cursor", {
    bufnr = bufnr,
    line = line,
    col = col,
  })

  local prompts = M.find_prompts_in_buffer(bufnr)

  logger.debug("parser", "get_prompt_at_cursor: checking " .. #prompts .. " prompts")

  for i, prompt in ipairs(prompts) do
    logger.debug(
      "parser",
      "get_prompt_at_cursor: checking prompt " .. i .. " (lines " .. prompt.start_line .. "-" .. prompt.end_line .. ")"
    )
    if line >= prompt.start_line and line <= prompt.end_line then
      logger.debug("parser", "get_prompt_at_cursor: cursor line " .. line .. " is within prompt line range")
      if line == prompt.start_line and col < prompt.start_col then
        logger.debug(
          "parser",
          "get_prompt_at_cursor: cursor col " .. col .. " is before prompt start_col " .. prompt.start_col
        )
        goto continue
      end
      if line == prompt.end_line and col > prompt.end_col then
        logger.debug(
          "parser",
          "get_prompt_at_cursor: cursor col " .. col .. " is after prompt end_col " .. prompt.end_col
        )
        goto continue
      end
      logger.debug("parser", "get_prompt_at_cursor: found prompt at cursor")
      logger.func_exit("parser", "get_prompt_at_cursor", "prompt found")
      return prompt
    end
    ::continue::
  end

  logger.debug("parser", "get_prompt_at_cursor: no prompt found at cursor")
  logger.func_exit("parser", "get_prompt_at_cursor", nil)
  return nil
end

--- Get the last closed prompt in buffer
---@param bufnr? number Buffer number (default: current)
---@return CoderPrompt|nil Last prompt or nil
function M.get_last_prompt(bufnr)
  bufnr = bufnr or vim.api.nvim_get_current_buf()

  logger.func_entry("parser", "get_last_prompt", { bufnr = bufnr })

  local prompts = M.find_prompts_in_buffer(bufnr)

  if #prompts > 0 then
    local last = prompts[#prompts]
    logger.debug("parser", "get_last_prompt: returning prompt at line " .. last.start_line)
    logger.func_exit("parser", "get_last_prompt", "prompt at line " .. last.start_line)
    return last
  end

  logger.debug("parser", "get_last_prompt: no prompts found")
  logger.func_exit("parser", "get_last_prompt", nil)
  return nil
end

--- Extract the prompt type from content
---@param content string Prompt content
---@return "refactor" | "add" | "document" | "explain" | "generic" Prompt type
function M.detect_prompt_type(content)
  logger.func_entry("parser", "detect_prompt_type", { content_preview = content:sub(1, 50) })

  local lower = content:lower()

  if lower:match("refactor") then
    logger.debug("parser", "detect_prompt_type: detected 'refactor'")
    logger.func_exit("parser", "detect_prompt_type", "refactor")
    return "refactor"
  elseif lower:match("add") or lower:match("create") or lower:match("implement") then
    logger.debug("parser", "detect_prompt_type: detected 'add'")
    logger.func_exit("parser", "detect_prompt_type", "add")
    return "add"
  elseif lower:match("document") or lower:match("comment") or lower:match("jsdoc") then
    logger.debug("parser", "detect_prompt_type: detected 'document'")
    logger.func_exit("parser", "detect_prompt_type", "document")
    return "document"
  elseif lower:match("explain") or lower:match("what") or lower:match("how") then
    logger.debug("parser", "detect_prompt_type: detected 'explain'")
    logger.func_exit("parser", "detect_prompt_type", "explain")
    return "explain"
  end

  logger.debug("parser", "detect_prompt_type: detected 'generic'")
  logger.func_exit("parser", "detect_prompt_type", "generic")
  return "generic"
end

--- Clean prompt content (trim whitespace, normalize newlines)
---@param content string Raw prompt content
---@return string Cleaned content
function M.clean_prompt(content)
  logger.func_entry("parser", "clean_prompt", { content_length = #content })

  -- Trim leading/trailing whitespace
  content = content:match("^%s*(.-)%s*$")
  -- Normalize multiple newlines
  content = content:gsub("\n\n\n+", "\n\n")

  logger.debug("parser", "clean_prompt: cleaned from " .. #content .. " chars")
  logger.func_exit("parser", "clean_prompt", "length=" .. #content)

  return content
end

--- Check if line contains a closing tag
---@param line string Line to check
---@param close_tag string Closing tag
---@return boolean
function M.has_closing_tag(line, close_tag)
  logger.func_entry("parser", "has_closing_tag", { line_preview = line:sub(1, 30), close_tag = close_tag })

  local result = line:find(utils.escape_pattern(close_tag)) ~= nil

  logger.debug("parser", "has_closing_tag: result=" .. tostring(result))
  logger.func_exit("parser", "has_closing_tag", result)

  return result
end

--- Check if buffer has any unclosed prompts
---@param bufnr? number Buffer number (default: current)
---@return boolean
function M.has_unclosed_prompts(bufnr)
  bufnr = bufnr or vim.api.nvim_get_current_buf()

  logger.func_entry("parser", "has_unclosed_prompts", { bufnr = bufnr })

  local lines = vim.api.nvim_buf_get_lines(bufnr, 0, -1, false)
  local content = table.concat(lines, "\n")

  local cfg = get_config()
  local escaped_open = utils.escape_pattern(cfg.patterns.open_tag)
  local escaped_close = utils.escape_pattern(cfg.patterns.close_tag)

  local _, open_count = content:gsub(escaped_open, "")
  local _, close_count = content:gsub(escaped_close, "")

  local has_unclosed = open_count > close_count

  logger.debug(
    "parser",
    "has_unclosed_prompts: open=" .. open_count .. ", close=" .. close_count .. ", unclosed=" .. tostring(has_unclosed)
  )
  logger.func_exit("parser", "has_unclosed_prompts", has_unclosed)

  return has_unclosed
end

--- Extract file references from prompt content
--- Matches @filename patterns but NOT @/ (closing tag)
---@param content string Prompt content
---@return string[] List of file references
function M.extract_file_references(content)
  logger.func_entry("parser", "extract_file_references", { content_length = #content })

  local files = {}
  -- Pattern: @ followed by word char, dot, underscore, or dash as FIRST char
  -- Then optionally more path characters including /
  -- This ensures @/ is NOT matched (/ cannot be first char)
  for file in content:gmatch("@([%w%._%-][%w%._%-/]*)") do
    if file ~= "" then
      table.insert(files, file)
      logger.debug("parser", "extract_file_references: found file reference: " .. file)
    end
  end

  logger.debug("parser", "extract_file_references: found " .. #files .. " file references")
  logger.func_exit("parser", "extract_file_references", files)

  return files
end

--- Remove file references from prompt content (for clean prompt text)
---@param content string Prompt content
---@return string Cleaned content without file references
function M.strip_file_references(content)
  logger.func_entry("parser", "strip_file_references", { content_length = #content })

  -- Remove @filename patterns but preserve @/ closing tag
  -- Pattern requires first char after @ to be word char, dot, underscore, or dash (NOT /)
  local result = content:gsub("@([%w%._%-][%w%._%-/]*)", "")

  logger.debug("parser", "strip_file_references: stripped " .. (#content - #result) .. " chars")
  logger.func_exit("parser", "strip_file_references", "length=" .. #result)

  return result
end

--- Check if cursor is inside an unclosed prompt tag
---@param bufnr? number Buffer number (default: current)
---@return boolean is_inside Whether cursor is inside an open tag
---@return number|nil start_line Line where the open tag starts
function M.is_cursor_in_open_tag(bufnr)
  bufnr = bufnr or vim.api.nvim_get_current_buf()

  logger.func_entry("parser", "is_cursor_in_open_tag", { bufnr = bufnr })

  local cursor = vim.api.nvim_win_get_cursor(0)
  local cursor_line = cursor[1]

  local lines = vim.api.nvim_buf_get_lines(bufnr, 0, cursor_line, false)
  local cfg = get_config()
  local escaped_open = utils.escape_pattern(cfg.patterns.open_tag)
  local escaped_close = utils.escape_pattern(cfg.patterns.close_tag)

  local open_count = 0
  local close_count = 0
  local last_open_line = nil

  for line_num, line in ipairs(lines) do
    -- Count opens on this line
    for _ in line:gmatch(escaped_open) do
      open_count = open_count + 1
      last_open_line = line_num
      logger.debug("parser", "is_cursor_in_open_tag: found open tag at line " .. line_num)
    end
    -- Count closes on this line
    for _ in line:gmatch(escaped_close) do
      close_count = close_count + 1
      logger.debug("parser", "is_cursor_in_open_tag: found close tag at line " .. line_num)
    end
  end

  local is_inside = open_count > close_count

  logger.debug(
    "parser",
    "is_cursor_in_open_tag: open="
      .. open_count
      .. ", close="
      .. close_count
      .. ", is_inside="
      .. tostring(is_inside)
      .. ", last_open_line="
      .. tostring(last_open_line)
  )
  logger.func_exit("parser", "is_cursor_in_open_tag", { is_inside = is_inside, last_open_line = last_open_line })

  return is_inside, is_inside and last_open_line or nil
end

--- Get the word being typed after @ symbol
---@param bufnr? number Buffer number
---@return string|nil prefix The text after @ being typed, or nil if not typing a file ref
function M.get_file_ref_prefix(bufnr)
  bufnr = bufnr or vim.api.nvim_get_current_buf()

  logger.func_entry("parser", "get_file_ref_prefix", { bufnr = bufnr })

  local cursor = vim.api.nvim_win_get_cursor(0)
  local line = vim.api.nvim_buf_get_lines(bufnr, cursor[1] - 1, cursor[1], false)[1]
  if not line then
    logger.debug("parser", "get_file_ref_prefix: no line at cursor")
    logger.func_exit("parser", "get_file_ref_prefix", nil)
    return nil
  end

  local col = cursor[2]
  local before_cursor = line:sub(1, col)

  -- Check if we're typing after @ but not @/
  -- Match @ followed by optional path characters at end of string
  local prefix = before_cursor:match("@([%w%._%-/]*)$")

  -- Make sure it's not the closing tag pattern
  if prefix and before_cursor:sub(-2) == "@/" then
    logger.debug("parser", "get_file_ref_prefix: closing tag detected, returning nil")
    logger.func_exit("parser", "get_file_ref_prefix", nil)
    return nil
  end

  logger.debug("parser", "get_file_ref_prefix: prefix=" .. tostring(prefix))
  logger.func_exit("parser", "get_file_ref_prefix", prefix)

  return prefix
end

logger.info("parser", "Parser module loaded")

return M