--- The `:Heph <subcommand>` user-command surface. Tactical/Organizational task
--- views (next/list/capture/...) arrive with slice 11b; this is the knowledge-
--- base core (journal, links).

local M = {}

local ATTENTIONS = { "white", "orange", "red", "blue" }

--- subcommand -> handler(args: string[])
M.subs = {
  -- knowledge base
  today = function()
    require("heph.journal").open()
  end,
  journal = function(args)
    require("heph.journal").open(args[1])
  end,
  follow = function()
    require("heph.link").follow()
  end,
  open = function(args)
    if args[1] then
      require("heph.node").open(args[1])
    end
  end,
  search = function(args)
    local query = table.concat(args, " ")
    if #query == 0 then
      require("heph.util").notify("usage: :Heph search <query>", vim.log.levels.WARN)
      return
    end
    local nodes = require("heph.rpc").call("search", { query = query })
    require("heph.picker").select(nodes, {
      prompt = "heph search: " .. query,
      format = function(n)
        return string.format("[%s] %s", n.kind, n.title)
      end,
    }, function(choice)
      if choice then
        require("heph.node").open(choice.id)
      end
    end)
  end,

  -- tasks
  next = function(args)
    require("heph.view").next({ scope = args[1] })
  end,
  list = function(args)
    require("heph.view").list({ attention = args[1] })
  end,
  capture = function(args)
    local title = table.concat(args, " ")
    if #title == 0 then
      require("heph.util").notify("usage: :Heph capture <title>", vim.log.levels.WARN)
      return
    end
    require("heph.picker").select(ATTENTIONS, { prompt = "attention for: " .. title }, function(attention)
      require("heph.task").capture(title, { attention = attention })
      require("heph.util").notify("captured: " .. title)
    end)
  end,
  attention = function(args)
    if args[1] then
      require("heph.task").set_attention_current(args[1])
    else
      require("heph.picker").select(ATTENTIONS, { prompt = "attention" }, function(choice)
        if choice then
          require("heph.task").set_attention_current(choice)
        end
      end)
    end
  end,
  done = function()
    require("heph.task").set_state_current("done")
  end,
  drop = function()
    require("heph.task").set_state_current("dropped")
  end,
  skip = function()
    require("heph.task").skip_current()
  end,
  log = function(args)
    require("heph.task").log_append_current(table.concat(args, " "))
  end,
}

--- `:Heph` entry point.
function M.run(opts)
  local args = opts.fargs
  local sub = args[1]
  if not sub then
    require("heph.util").notify("usage: :Heph <" .. table.concat(M.names(), "|") .. ">", vim.log.levels.WARN)
    return
  end
  local handler = M.subs[sub]
  if not handler then
    require("heph.util").notify("unknown subcommand: " .. sub, vim.log.levels.ERROR)
    return
  end
  local ok, err = pcall(handler, vim.list_slice(args, 2))
  if not ok then
    require("heph.util").notify(tostring(err), vim.log.levels.ERROR)
  end
end

--- Sorted subcommand names.
function M.names()
  local names = vim.tbl_keys(M.subs)
  table.sort(names)
  return names
end

--- Completion: subcommand names at the first position.
function M.complete(arglead, cmdline, _cursorpos)
  -- Only complete the subcommand token (first arg after :Heph).
  if cmdline:match("^%s*Heph%s+%S*$") then
    return vim.tbl_filter(function(n)
      return n:find(arglead, 1, true) == 1
    end, M.names())
  end
  return {}
end

return M