// SPDX-FileCopyrightText: 2017 Stefan Majewsky <majewsky@gmx.net>
// SPDX-License-Identifier: GPL-3.0-only

package prompt

import (
	"os"
	"path/filepath"
	"strings"
)

// Directory contains all data about a directory that the prompt needs.
type Directory struct {
	Path                  string
	DisplayPath           string //formatted for display in prompt line
	TitlePath             string //formatted for display in TerminalTitle
	InBuildTree           bool
	InRepoTree            bool
	Repo                  *gitRepo
	NearestAccessiblePath string
}

// CurrentDirectory prepares a Directory struct for the current working directory.
func CurrentDirectory() Directory {
	cwd, err := os.Getwd()
	if err != nil {
		cwd = filepath.Clean(os.Getenv("PWD"))
	}
	return NewDirectory(cwd)
}

// NewDirectory prepares a Directory struct for the given path.
func NewDirectory(path string) (dir Directory) {
	dir.Path = path
	dir.DisplayPath = path

	//check if path actually exists
	dir.NearestAccessiblePath = findNearestAccessiblePath(dir.Path)
	if dir.NearestAccessiblePath == dir.Path {
		//marks that everything is okay existence-wise
		dir.NearestAccessiblePath = ""

		//display tag if below /x/build
		if buildPath := os.Getenv("BUILD_ROOT"); buildPath != "" {
			rel, _ := filepath.Rel(buildPath, dir.DisplayPath)
			if !strings.HasPrefix(rel, "..") && rel != "." {
				dir.InBuildTree = true
				dir.DisplayPath = filepath.Join("/", rel)
			}
		}

		//display tag if below /x/src
		if gopath := os.Getenv("GOPATH"); gopath != "" {
			repoPath := filepath.Join(gopath, "src")
			rel, _ := filepath.Rel(repoPath, dir.DisplayPath)
			if !strings.HasPrefix(rel, "..") && rel != "." {
				dir.InRepoTree = true
				dir.DisplayPath = rel
			}
		}

		//terminal title has the same path truncations as above, but differs from
		//this point
		dir.TitlePath = dir.DisplayPath

		//strip $HOME prefix if applicable and desirable
		dir.stripHomeDirFromDisplay()

		//check if we are inside a Git repository
		var err error
		dir.Repo, err = findRepo(dir.Path)
		handleError(err)

		//inside a repository, terminal title only shows the repo directory and
		//below (e.g. "gofu/internal/prompt" for the current directory)
		if dir.Repo != nil {
			dir.TitlePath, _ = filepath.Rel(filepath.Dir(dir.Repo.RootPath), dir.Path)
		}
	}

	return
}

// This part can benefit from a "return" in the middle, so it's in a separate function.
func (dir *Directory) stripHomeDirFromDisplay() {
	if !strings.HasPrefix(dir.DisplayPath, "/") {
		return
	}

	homePath := os.Getenv("HOME")
	if homePath == "" {
		return
	}

	rel, _ := filepath.Rel(homePath, dir.DisplayPath)
	if rel == "." {
		//do not display an empty DisplayPath if tags are displayed
		if dir.InBuildTree || dir.InRepoTree {
			return
		}
		dir.DisplayPath = ""
		dir.TitlePath = "~"
		return
	}

	if !strings.HasPrefix(rel, "..") {
		dir.DisplayPath = rel
		dir.TitlePath = "~/" + rel
	}
}

func findNearestAccessiblePath(path string) string {
	_, err := os.Stat(path)
	if err == nil {
		return path
	}
	return findNearestAccessiblePath(filepath.Dir(path))
}

func getDirectoryField(dir Directory, tt *TerminalTitle) string {
	tt.Path = dir.TitlePath
	if dir.DisplayPath == "" {
		return ""
	}

	txt := withColor("1;36", dir.DisplayPath)
	if dir.NearestAccessiblePath == "" {
		//cwd accessible -> highlight path elements inside the repo (if any)
		if dir.Repo != nil && dir.Repo.RootPath != dir.Path {
			rel, _ := filepath.Rel(dir.Repo.RootPath, dir.Path)
			if base, ok := strings.CutSuffix(dir.DisplayPath, rel); ok {
				txt = withColor("0;36", base) + withColor("1;36", rel)
			}
		}
	} else {
		//cwd inaccessible -> highlight inaccessible path elements
		rel, _ := filepath.Rel(dir.NearestAccessiblePath, dir.Path)
		txt = withColor("1;36", dir.NearestAccessiblePath+"/") + withColor("1;31", rel)
	}

	//apply tags
	if dir.InRepoTree {
		txt = withType("repo", txt)
	}
	if dir.InBuildTree {
		txt = withType("build", txt)
		tt.Path = "build:" + tt.Path
	}
	return txt
}

func getDeletedMessageField(dir Directory) string {
	if dir.NearestAccessiblePath == "" {
		return ""
	}
	return withColor("1;41", "cannot stat cwd")
}