local M = {}

local ns = nil
local log_buf = nil
local log_ns = nil

function M.init(hobs_ns)
  ns = hobs_ns
  log_ns = vim.api.nvim_create_namespace("hobs.nvim.log")

  vim.api.nvim_set_hl(log_ns, "HobLogTimestamp", { fg = "grey", bold = true })
  vim.api.nvim_set_hl(log_ns, "HobLogTagStarted", { fg = "#4ade80", bold = true })
  vim.api.nvim_set_hl(log_ns, "HobLogTagFinished", { fg = "#60a5fa", bold = true })
  vim.api.nvim_set_hl(log_ns, "HobLogTagFailed", { fg = "#f87171", bold = true })
  vim.api.nvim_set_hl(log_ns, "HobLogTagError", { fg = "#fb923c", bold = true })
  vim.api.nvim_set_hl(log_ns, "HobLogSed", { fg = "#a78bfa" })
  vim.api.nvim_set_hl(log_ns, "HobLogSeparator", { fg = "#71717a" })
end

local function get_log_buf()
  if log_buf and vim.api.nvim_buf_is_valid(log_buf) then
    return log_buf
  end

  log_buf = vim.api.nvim_create_buf(false, true)
  vim.api.nvim_buf_set_name(log_buf, "hobs://log")
  vim.bo[log_buf].buftype = "nofile"
  vim.bo[log_buf].bufhidden = "hide"
  vim.bo[log_buf].swapfile = false
  vim.bo[log_buf].filetype = "log"
  vim.bo[log_buf].modifiable = false

  return log_buf
end

local function append_to_log(lines, hl_group)
  local buf = get_log_buf()
  local base_row = vim.api.nvim_buf_line_count(buf)

  vim.bo[buf].modifiable = true
  vim.api.nvim_buf_set_lines(buf, -1, -1, false, lines)
  vim.bo[buf].modifiable = false

  if hl_group then
    local end_row = vim.api.nvim_buf_line_count(buf) - 1
    for row = base_row, end_row do
      vim.api.nvim_buf_add_highlight(buf, log_ns, hl_group, row, 0, -1)
    end
  end
end

local function timestamp()
  return os.date("%Y-%m-%d %H:%M:%S")
end

local function log_entry(tag, msg, hl_group)
  local lines = vim.split(msg, "\n", { plain = true })

  local prefix = string.format("[%s] %s:", timestamp(), tag)
  lines[1] = prefix .. " " .. lines[1]
  for i = 2, #lines do
    lines[i] = "" .. lines[i]
  end

  if hl_group and #lines == 1 then
    local buf = get_log_buf()
    local base_row = vim.api.nvim_buf_line_count(buf)

    vim.bo[buf].modifiable = true
    vim.api.nvim_buf_set_lines(buf, -1, -1, false, lines)

    local tag_end_col = #prefix
    vim.api.nvim_buf_add_highlight(buf, log_ns, "HobLogTimestamp", base_row, 0, tag_end_col)
    vim.api.nvim_buf_add_highlight(buf, log_ns, hl_group, base_row, tag_end_col, -1)

    vim.bo[buf].modifiable = false
  else
    append_to_log(lines)
  end
end

function M.log_info(msg, hl_group)
  append_to_log({ string.format("[%s] INFO: %s", timestamp(), msg) }, hl_group)
end

function M.log_error(msg)
  log_entry("ERROR", msg, "HobLogTagError")
end

function M.log_hob_started(id, filename, prompt)
  local filename_short = vim.fn.fnamemodify(filename, ":t")
  local msg = string.format("Hob %d started | %s | %s", id, filename_short, prompt)
  log_entry("HOB", msg, "HobLogTagStarted")
end

function M.log_hob_working(id, status)
  log_entry("HOB", string.format("Hob %d: %s", id, status))
end

function M.log_hob_sed(id, script)
  local buf = get_log_buf()

  vim.bo[buf].modifiable = true
  local base_row = vim.api.nvim_buf_line_count(buf)

  local separator_line = string.format("===== Hob %d sed script =====", id)
  vim.api.nvim_buf_set_lines(buf, -1, -1, false, { separator_line })
  vim.api.nvim_buf_add_highlight(buf, log_ns, "HobLogSeparator", base_row, 0, -1)

  local sed_lines = vim.split(script, "\n", { plain = true })
  if #sed_lines > 0 then
    vim.api.nvim_buf_set_lines(buf, -1, -1, false, sed_lines)

    for i = 1, #sed_lines do
      vim.api.nvim_buf_add_highlight(buf, log_ns, "HobLogSed", base_row + i - 1, 0, -1)
    end
  end

  local end_sep_row = vim.api.nvim_buf_line_count(buf) - 1
  vim.api.nvim_buf_set_lines(buf, -1, -1, false, { "===== end sed script =====" })
  vim.api.nvim_buf_add_highlight(buf, log_ns, "HobLogSeparator", end_sep_row, 0, -1)

  vim.bo[buf].modifiable = false
end

function M.log_hob_finished(id)
  log_entry("HOB", string.format("Hob %d finished and applied edit", id), "HobLogTagFinished")
end

function M.log_hob_failed(id, reason)
  log_entry("HOB", string.format("Hob %d failed: %s", id, reason or "unknown error"), "HobLogTagFailed")
end

function M.log_hob_edit_failed(id, reason)
  log_entry("HOB", string.format("Hob %d edit failed: %s", id, reason or "unknown error"), "HobLogTagFailed")
end

function M.open()
  local buf = get_log_buf()
  if not buf or not vim.api.nvim_buf_is_valid(buf) then
    return
  end

  local win = vim.api.nvim_get_current_win()
  local win_height = vim.api.nvim_win_get_height(win)

  vim.cmd("botright split")
  vim.api.nvim_win_set_buf(0, buf)

  local log_height = math.min(15, math.ceil(win_height * 0.4))
  vim.api.nvim_win_set_height(0, log_height)
  vim.api.nvim_win_set_hl_ns(0, log_ns)

  local lines_count = vim.api.nvim_buf_line_count(buf)
  if lines_count > 0 then
    local col = vim.fn.min({ vim.api.nvim_win_get_width(0) - 1, vim.fn.strwidth(vim.api.nvim_get_current_line()) })
    vim.api.nvim_win_set_cursor(0, { lines_count, col })
  end

  vim.cmd("startinsert")
end

function M.reset()
  if log_buf and vim.api.nvim_buf_is_valid(log_buf) then
    vim.api.nvim_buf_delete(log_buf, { force = true })
    log_buf = nil
  end
end

return M