// SPDX-FileCopyrightText: Amolith <amolith@secluded.site>
//
// SPDX-License-Identifier: AGPL-3.0-or-later

package main

import (
	"bufio"
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"github.com/spf13/cobra"
)

var installCmd = &cobra.Command{
	Use:   "install",
	Short: "Create symlinks for git formatted-commit and git formatted-tag",
	Long: `Creates symlinks in ~/.local/bin so you can use:
  git formatted-commit ...
  git formatted-tag ...

The symlinks point to this binary and dispatch based on the invocation name.`,
	RunE: func(cmd *cobra.Command, args []string) error {
		return runInstall()
	},
}

func runInstall() error {
	execPath, err := os.Executable()
	if err != nil {
		return fmt.Errorf("failed to determine executable path: %w", err)
	}
	execPath, err = filepath.EvalSymlinks(execPath)
	if err != nil {
		return fmt.Errorf("failed to resolve executable path: %w", err)
	}

	homeDir, err := os.UserHomeDir()
	if err != nil {
		return fmt.Errorf("failed to determine home directory: %w", err)
	}

	binDir := filepath.Join(homeDir, ".local", "bin")
	if err := os.MkdirAll(binDir, 0o755); err != nil {
		return fmt.Errorf("failed to create %s: %w", binDir, err)
	}

	symlinks := []struct {
		name string
		path string
	}{
		{"git-formatted-commit", filepath.Join(binDir, "git-formatted-commit")},
		{"git-formatted-tag", filepath.Join(binDir, "git-formatted-tag")},
	}

	for _, link := range symlinks {
		if err := createSymlink(execPath, link.path, link.name); err != nil {
			return err
		}
	}

	checkPath(binDir)
	return nil
}

func createSymlink(target, linkPath, name string) error {
	info, err := os.Lstat(linkPath)
	if err == nil {
		if info.Mode()&os.ModeSymlink == 0 {
			fmt.Fprintf(os.Stderr, "Error: %s exists and is not a symlink\n", linkPath)
			fmt.Fprintln(os.Stderr, "  Refusing to overwrite. Remove it manually if intended.")
			return fmt.Errorf("cannot overwrite non-symlink at %s", linkPath)
		}

		existingTarget, err := os.Readlink(linkPath)
		if err != nil {
			return fmt.Errorf("failed to read existing symlink %s: %w", linkPath, err)
		}

		if existingTarget == target {
			fmt.Printf("  %s → %s (already exists, same target)\n", name, target)
			return nil
		}

		fmt.Printf("  %s exists, points to %s\n", linkPath, existingTarget)
		fmt.Printf("  Overwrite to point to %s? [y/N] ", target)

		reader := bufio.NewReader(os.Stdin)
		response, err := reader.ReadString('\n')
		if err != nil {
			return fmt.Errorf("failed to read response: %w", err)
		}

		response = strings.TrimSpace(strings.ToLower(response))
		if response != "y" && response != "yes" {
			fmt.Printf("  Skipping %s\n", name)
			return nil
		}

		if err := os.Remove(linkPath); err != nil {
			return fmt.Errorf("failed to remove existing symlink: %w", err)
		}
	} else if !os.IsNotExist(err) {
		return fmt.Errorf("failed to check %s: %w", linkPath, err)
	}

	if err := os.Symlink(target, linkPath); err != nil {
		return fmt.Errorf("failed to create symlink %s: %w", linkPath, err)
	}

	fmt.Printf("  Created %s → %s\n", name, target)
	return nil
}

func checkPath(binDir string) {
	pathEnv := os.Getenv("PATH")
	paths := filepath.SplitList(pathEnv)

	for _, p := range paths {
		if p == binDir {
			return
		}
	}

	fmt.Println()
	fmt.Printf("⚠ Warning: %s is not in your PATH\n", binDir)
	fmt.Println("  Add this to your shell config:")
	fmt.Printf("    export PATH=\"$HOME/.local/bin:$PATH\"\n")
}