//go:build linux

package dpkg

import (
	"bytes"
	"context"
	"fmt"
	"os/exec"
	"strings"

	"github.com/gogrlx/snack"
)

func available() bool {
	_, err := exec.LookPath("dpkg")
	return err == nil
}

func install(ctx context.Context, pkgs []snack.Target, opts ...snack.Option) (snack.InstallResult, error) {
	o := snack.ApplyOptions(opts...)
	var toInstall []snack.Target
	var unchanged []string
	for _, t := range pkgs {
		if o.Reinstall || t.Version != "" || o.DryRun {
			toInstall = append(toInstall, t)
			continue
		}
		ok, err := isInstalled(ctx, t.Name)
		if err != nil {
			return snack.InstallResult{}, err
		}
		if ok {
			unchanged = append(unchanged, t.Name)
		} else {
			toInstall = append(toInstall, t)
		}
	}
	if len(toInstall) > 0 {
		var args []string
		if o.Sudo {
			args = append(args, "sudo")
		}
		args = append(args, "dpkg", "-i")
		if o.DryRun {
			args = append(args, "--simulate")
		}
		for _, t := range toInstall {
			if t.Source != "" {
				args = append(args, t.Source)
			} else {
				args = append(args, t.Name)
			}
		}
		cmd := exec.CommandContext(ctx, args[0], args[1:]...)
		var stderr bytes.Buffer
		cmd.Stderr = &stderr
		if err := cmd.Run(); err != nil {
			errMsg := stderr.String()
			if strings.Contains(errMsg, "Permission denied") || strings.Contains(errMsg, "are you root") {
				return snack.InstallResult{}, fmt.Errorf("dpkg -i: %w", snack.ErrPermissionDenied)
			}
			return snack.InstallResult{}, fmt.Errorf("dpkg -i: %w: %s", err, errMsg)
		}
	}
	var installed []snack.Package
	for _, t := range toInstall {
		v, _ := version(ctx, t.Name)
		installed = append(installed, snack.Package{Name: t.Name, Version: v, Installed: true})
	}
	return snack.InstallResult{Installed: installed, Unchanged: unchanged}, nil
}

func remove(ctx context.Context, pkgs []snack.Target, opts ...snack.Option) (snack.RemoveResult, error) {
	o := snack.ApplyOptions(opts...)
	var toRemove []snack.Target
	var unchanged []string
	for _, t := range pkgs {
		if o.DryRun {
			toRemove = append(toRemove, t)
			continue
		}
		ok, err := isInstalled(ctx, t.Name)
		if err != nil {
			return snack.RemoveResult{}, err
		}
		if !ok {
			unchanged = append(unchanged, t.Name)
		} else {
			toRemove = append(toRemove, t)
		}
	}
	if len(toRemove) > 0 {
		var args []string
		if o.Sudo {
			args = append(args, "sudo")
		}
		args = append(args, "dpkg", "-r")
		if o.DryRun {
			args = append(args, "--simulate")
		}
		args = append(args, snack.TargetNames(toRemove)...)
		cmd := exec.CommandContext(ctx, args[0], args[1:]...)
		var stderr bytes.Buffer
		cmd.Stderr = &stderr
		if err := cmd.Run(); err != nil {
			return snack.RemoveResult{}, fmt.Errorf("dpkg -r: %w: %s", err, stderr.String())
		}
	}
	var removed []snack.Package
	for _, t := range toRemove {
		removed = append(removed, snack.Package{Name: t.Name})
	}
	return snack.RemoveResult{Removed: removed, Unchanged: unchanged}, nil
}

func purge(ctx context.Context, pkgs []snack.Target, opts ...snack.Option) error {
	o := snack.ApplyOptions(opts...)
	var args []string
	if o.Sudo {
		args = append(args, "sudo")
	}
	args = append(args, "dpkg", "-P")
	if o.DryRun {
		args = append(args, "--simulate")
	}
	args = append(args, snack.TargetNames(pkgs)...)
	cmd := exec.CommandContext(ctx, args[0], args[1:]...)
	var stderr bytes.Buffer
	cmd.Stderr = &stderr
	if err := cmd.Run(); err != nil {
		return fmt.Errorf("dpkg -P: %w: %s", err, stderr.String())
	}
	return nil
}

func list(ctx context.Context) ([]snack.Package, error) {
	cmd := exec.CommandContext(ctx, "dpkg-query", "-W", "-f=${Package}\\t${Version}\\t${Status}\\n")
	out, err := cmd.Output()
	if err != nil {
		return nil, fmt.Errorf("dpkg-query list: %w", err)
	}
	return parseList(string(out)), nil
}

func search(ctx context.Context, query string) ([]snack.Package, error) {
	pattern := fmt.Sprintf("*%s*", query)
	cmd := exec.CommandContext(ctx, "dpkg-query", "-l", pattern)
	out, err := cmd.Output()
	if err != nil {
		// dpkg-query -l returns exit 1 when no packages match
		return nil, nil
	}
	return parseDpkgList(string(out)), nil
}

func info(ctx context.Context, pkg string) (*snack.Package, error) {
	cmd := exec.CommandContext(ctx, "dpkg-query", "-s", pkg)
	var stderr bytes.Buffer
	cmd.Stderr = &stderr
	out, err := cmd.Output()
	if err != nil {
		if strings.Contains(stderr.String(), "is not installed") || strings.Contains(stderr.String(), "not found") {
			return nil, fmt.Errorf("dpkg-query -s %s: %w", pkg, snack.ErrNotInstalled)
		}
		return nil, fmt.Errorf("dpkg-query -s %s: %w", pkg, err)
	}
	return parseInfo(string(out))
}

func isInstalled(ctx context.Context, pkg string) (bool, error) {
	cmd := exec.CommandContext(ctx, "dpkg-query", "-W", "-f=${Status}", pkg)
	out, err := cmd.Output()
	if err != nil {
		return false, nil
	}
	return strings.TrimSpace(string(out)) == "install ok installed", nil
}

func version(ctx context.Context, pkg string) (string, error) {
	cmd := exec.CommandContext(ctx, "dpkg-query", "-W", "-f=${Version}", pkg)
	out, err := cmd.Output()
	if err != nil {
		return "", fmt.Errorf("version %s: %w", pkg, snack.ErrNotInstalled)
	}
	v := strings.TrimSpace(string(out))
	if v == "" {
		return "", fmt.Errorf("version %s: %w", pkg, snack.ErrNotInstalled)
	}
	return v, nil
}