package git_commands

import (
	"strings"

	"github.com/jesseduffield/lazygit/pkg/commands/oscommands"
)

// OptionalLocksEnvVar is the name of the environment variable that tells git
// whether it may take "optional" locks — chiefly the index.lock that `git
// status` grabs to write back a refreshed stat-cache. We set it to 0 on every
// git command by default (see NewGitCmdObjBuilder) so our invocations never
// contend for index.lock, neither with each other (e.g. a main-view `git diff
// --submodule`, which runs `git status` inside submodules, racing a submodule
// action) nor with git commands the user runs in a terminal. The one command
// that opts back in is the foreground files refresh; see FileLoader.gitStatus.
const OptionalLocksEnvVar = "GIT_OPTIONAL_LOCKS"

// convenience struct for building git commands. Especially useful when
// including conditional args
type GitCommandBuilder struct {
	// command string
	args []string
}

func NewGitCmd(command string) *GitCommandBuilder {
	return &GitCommandBuilder{args: []string{command}}
}

func (self *GitCommandBuilder) Arg(args ...string) *GitCommandBuilder {
	self.args = append(self.args, args...)

	return self
}

func (self *GitCommandBuilder) ArgIf(condition bool, ifTrue ...string) *GitCommandBuilder {
	if condition {
		self.Arg(ifTrue...)
	}

	return self
}

func (self *GitCommandBuilder) ArgIfElse(condition bool, ifTrue string, ifFalse string) *GitCommandBuilder {
	if condition {
		return self.Arg(ifTrue)
	}
	return self.Arg(ifFalse)
}

// GlobalArg adds top-level options for git itself (e.g. --no-optional-locks).
// Unlike Arg, these are prepended before the command, where git expects them.
func (self *GitCommandBuilder) GlobalArg(args ...string) *GitCommandBuilder {
	self.args = append(append([]string{}, args...), self.args...)

	return self
}

func (self *GitCommandBuilder) GlobalArgIf(condition bool, args ...string) *GitCommandBuilder {
	if condition {
		self.GlobalArg(args...)
	}

	return self
}

func (self *GitCommandBuilder) Config(value string) *GitCommandBuilder {
	// config settings come before the command
	self.args = append([]string{"-c", value}, self.args...)

	return self
}

func (self *GitCommandBuilder) ConfigIf(condition bool, ifTrue string) *GitCommandBuilder {
	if condition {
		self.Config(ifTrue)
	}

	return self
}

// the -C arg will make git do a `cd` to the directory before doing anything else
func (self *GitCommandBuilder) Dir(path string) *GitCommandBuilder {
	// repo path comes before the command
	self.args = append([]string{"-C", path}, self.args...)

	return self
}

func (self *GitCommandBuilder) DirIf(condition bool, path string) *GitCommandBuilder {
	if condition {
		return self.Dir(path)
	}

	return self
}

// Note, you may prefer to use the Dir method instead of this one
func (self *GitCommandBuilder) Worktree(path string) *GitCommandBuilder {
	// worktree arg comes before the command
	self.args = append([]string{"--work-tree", path}, self.args...)

	return self
}

func (self *GitCommandBuilder) WorktreePathIf(condition bool, path string) *GitCommandBuilder {
	if condition {
		return self.Worktree(path)
	}

	return self
}

// Note, you may prefer to use the Dir method instead of this one
func (self *GitCommandBuilder) GitDir(path string) *GitCommandBuilder {
	// git dir arg comes before the command
	self.args = append([]string{"--git-dir", path}, self.args...)

	return self
}

func (self *GitCommandBuilder) GitDirIf(condition bool, path string) *GitCommandBuilder {
	if condition {
		return self.GitDir(path)
	}

	return self
}

func (self *GitCommandBuilder) ToArgv() []string {
	return append([]string{"git"}, self.args...)
}

func (self *GitCommandBuilder) ToString() string {
	return strings.Join(self.ToArgv(), " ")
}

// runGitCmdOnPaths runs `git <subcommand> -- <paths...>`, splitting into
// multiple calls if needed to stay under the OS command-line length limit.
// Windows CreateProcess has a ~32 KB limit; we use 30 KB as a safe threshold.
func runGitCmdOnPaths(subcommand string, paths []string, cmd oscommands.ICmdObjBuilder) error {
	const maxArgBytes = 30_000

	start := 0
	for start < len(paths) {
		end := start
		total := 0
		for end < len(paths) {
			total += len(paths[end]) + 1 // +1 for the separating space
			if total > maxArgBytes && end > start {
				break
			}
			end++
		}
		if err := cmd.New(NewGitCmd(subcommand).Arg("--").
			Arg(paths[start:end]...).
			ToArgv()).Run(); err != nil {
			return err
		}
		start = end
	}
	return nil
}