---@class snacks.gitbrowse
---@overload fun(opts?: snacks.gitbrowse.Config)
local M = setmetatable({}, {
  __call = function(t, ...)
    return t.open(...)
  end,
})

M.meta = {
  desc = "Open the current file, branch, commit, or repo in a browser (e.g. GitHub, GitLab, Bitbucket)",
}

local uv = vim.uv or vim.loop

---@class snacks.gitbrowse.Config
---@field url_patterns? table<string, table<string, string|fun(fields:snacks.gitbrowse.Fields):string>>
local defaults = {
  notify = true, -- show notification on open
  -- Handler to open the url in a browser
  ---@param url string
  open = function(url)
    if vim.fn.has("nvim-0.10") == 0 then
      require("lazy.util").open(url, { system = true })
      return
    end
    vim.ui.open(url)
  end,
  ---@type "repo" | "branch" | "file" | "commit" | "permalink"
  what = "commit", -- what to open. not all remotes support all types
  branch = nil, ---@type string?
  line_start = nil, ---@type number?
  line_end = nil, ---@type number?
  -- patterns to transform remotes to an actual URL
  -- stylua: ignore
  remote_patterns = {
    { "^(https?://.*)%.git$"              , "%1" },
    { "^git@(.+):(.+)%.git$"              , "https://%1/%2" },
    { "^git@(.+):(.+)$"                   , "https://%1/%2" },
    { "^git@(.+)/(.+)$"                   , "https://%1/%2" },
    { "^org%-%d+@(.+):(.+)%.git$"         , "https://%1/%2" },
    { "^ssh://git@(.*)$"                  , "https://%1" },
    { "^ssh://([^:/]+)(:%d+)/(.*)$"       , "https://%1/%3" },
    { "^ssh://([^/]+)/(.*)$"              , "https://%1/%2" },
    { "ssh%.dev%.azure%.com/v3/(.*)/(.*)$", "dev.azure.com/%1/_git/%2" },
    { "^https://%w*@(.*)"                 , "https://%1" },
    { "^git@(.*)"                         , "https://%1" },
    { ":%d+"                              , "" },
    { "%.git$"                            , "" },
  },
  url_patterns = {
    ["github%.com"] = {
      branch = "/tree/{branch}",
      file = "/blob/{branch}/{file}#L{line_start}-L{line_end}",
      permalink = "/blob/{commit}/{file}#L{line_start}-L{line_end}",
      commit = "/commit/{commit}",
    },
    ["gitlab%.com"] = {
      branch = "/-/tree/{branch}",
      file = "/-/blob/{branch}/{file}#L{line_start}-L{line_end}",
      permalink = "/-/blob/{commit}/{file}#L{line_start}-L{line_end}",
      commit = "/-/commit/{commit}",
    },
    ["bitbucket%.org"] = {
      branch = "/src/{branch}",
      file = "/src/{branch}/{file}#lines-{line_start}-L{line_end}",
      permalink = "/src/{commit}/{file}#lines-{line_start}-L{line_end}",
      commit = "/commits/{commit}",
    },
    ["git.sr.ht"] = {
      branch = "/tree/{branch}",
      file = "/tree/{branch}/item/{file}",
      permalink = "/tree/{commit}/item/{file}#L{line_start}",
      commit = "/commit/{commit}",
    },
  },
}

---@class snacks.gitbrowse.Fields
---@field branch? string
---@field file? string
---@field line_start? number
---@field line_end? number
---@field commit? string
---@field line_count? number

---@private
---@param remote string
---@param opts? snacks.gitbrowse.Config
function M.get_repo(remote, opts)
  opts = Snacks.config.get("gitbrowse", defaults, opts)
  local ret = remote
  for _, pattern in ipairs(opts.remote_patterns) do
    ret = ret:gsub(pattern[1], pattern[2]) --[[@as string]]
  end
  return ret:find("https://") == 1 and ret or ("https://%s"):format(ret)
end

---@param repo string
---@param fields snacks.gitbrowse.Fields
---@param opts? snacks.gitbrowse.Config
function M.get_url(repo, fields, opts)
  opts = Snacks.config.get("gitbrowse", defaults, opts)
  for remote, patterns in pairs(opts.url_patterns) do
    if repo:find(remote) then
      local pattern = patterns[opts.what]
      if type(pattern) == "string" then
        return repo .. pattern:gsub("(%b{})", function(key)
          return fields[key:sub(2, -2)] or key
        end)
      elseif type(pattern) == "function" then
        return repo .. pattern(fields)
      end
    end
  end
  return repo
end

---@param cmd string[]
---@param err string
local function system(cmd, err)
  local proc = vim.fn.system(cmd)
  if vim.v.shell_error ~= 0 then
    Snacks.notify.error({ err, proc }, { title = "Git Browse" })
    error("__ignore__")
  end
  return vim.split(vim.trim(proc), "\n")
end

---@param hash string
---@param cwd string
---@return boolean
local function is_valid_commit_hash(hash, cwd)
  if not (hash:match("^[a-fA-F0-9]+$") and #hash >= 7) then
    return false
  end
  system({ "git", "-C", cwd, "rev-parse", "--verify", hash }, "Invalid commit hash")
  return true
end

---@param opts? snacks.gitbrowse.Config
function M.open(opts)
  local ok, err = pcall(M._open, opts) -- errors are handled with notifications
  if not ok and err ~= "__ignore__" then
    error(err)
  end
end

---@param opts? snacks.gitbrowse.Config
function M._open(opts)
  opts = Snacks.config.get("gitbrowse", defaults, opts)
  local file = vim.api.nvim_buf_get_name(0) ---@type string?
  file = file and (uv.fs_stat(file) or {}).type == "file" and svim.fs.normalize(file) or nil
  local cwd = file and vim.fn.fnamemodify(file, ":h") or vim.fn.getcwd()

  ---@type snacks.gitbrowse.Fields
  local fields = {
    branch = opts.branch
      or system({ "git", "-C", cwd, "rev-parse", "--abbrev-ref", "HEAD" }, "Failed to get current branch")[1],
    file = file and system({ "git", "-C", cwd, "ls-files", "--full-name", file }, "Failed to get git file path")[1],
    line_start = opts.line_start,
    line_end = opts.line_end,
  }

  if opts.what == "permalink" then
    fields.commit = system(
      { "git", "-C", cwd, "log", "-n", "1", "--pretty=format:%H", "--", file },
      "Failed to get latest commit of file"
    )[1]
  else
    local word = vim.fn.expand("<cword>")
    fields.commit = is_valid_commit_hash(word, cwd) and word or nil
  end

  -- Get visual selection range if in visual mode
  if vim.fn.mode():find("[vV]") then
    vim.fn.feedkeys(":", "nx")
    local line_start = vim.api.nvim_buf_get_mark(0, "<")[1]
    local line_end = vim.api.nvim_buf_get_mark(0, ">")[1]
    vim.fn.feedkeys("gv", "nx")
    -- Ensure line_start is always the smaller number
    if line_start > line_end then
      line_start, line_end = line_end, line_start
    end
    fields.line_start = line_start
    fields.line_end = line_end
  else
    fields.line_start = fields.line_start or vim.fn.line(".")
    fields.line_end = fields.line_end or fields.line_start
  end
  fields.line_count = fields.line_end - fields.line_start + 1

  if not fields.commit and (opts.what == "commit" or opts.what == "permalink") then
    opts.what = "file"
  end
  if not fields.commit and not fields.file then
    opts.what = "branch"
  end
  if not fields.commit and not fields.branch then
    opts.what = "repo"
  end

  local remotes = {} ---@type {name:string, url:string}[]

  for _, line in ipairs(system({ "git", "-C", cwd, "remote", "-v" }, "Failed to get git remotes")) do
    local name, remote = line:match("(%S+)%s+(%S+)%s+%(fetch%)")
    if name and remote then
      local repo = M.get_repo(remote, opts)
      if repo then
        table.insert(remotes, {
          name = name,
          url = M.get_url(repo, fields, opts),
        })
      end
    end
  end

  local function open(remote)
    if remote then
      if opts.notify ~= false then
        Snacks.notify(("Opening [%s](%s)"):format(remote.name, remote.url), { title = "Git Browse" })
      end
      opts.open(remote.url)
    end
  end

  if #remotes == 0 then
    return Snacks.notify.error("No git remotes found", { title = "Git Browse" })
  elseif #remotes == 1 then
    return open(remotes[1])
  end

  vim.ui.select(remotes, {
    prompt = "Select remote to browse",
    format_item = function(item)
      return item.name .. (" "):rep(8 - #item.name) .. " 🔗 " .. item.url
    end,
  }, open)
end

return M