package browser

import (
	"encoding/json"
	"os"
	"path/filepath"
	"sort"
)

// ChromeProfile holds metadata about a single Chrome/Chromium profile directory.
type ChromeProfile struct {
	Dir            string // directory name (value for --profile-directory), e.g. "Default"
	Name           string // human-readable name from Local State info_cache, e.g. "Personal"
	Extensions     int    // number of installed extension dirs under <dir>/Extensions (excluding "Temp")
	HasPreferences bool   // true if <dir>/Preferences file exists
}

// localState mirrors the parts of Local State we need.
type localState struct {
	Profile struct {
		InfoCache map[string]struct {
			Name string `json:"name"`
		} `json:"info_cache"`
	} `json:"profile"`
}

// ListChromeProfiles scans userDataDir and returns one ChromeProfile per
// subdirectory that contains a Preferences file (excluding "System Profile").
// If userDataDir is empty it defaults to ~/.config/chromium.
// Names are resolved from Local State; if that file is missing or unparseable
// the profile Name field equals Dir.
func ListChromeProfiles(userDataDir string) ([]ChromeProfile, error) {
	if userDataDir == "" {
		home, err := os.UserHomeDir()
		if err != nil {
			return nil, err
		}
		userDataDir = filepath.Join(home, ".config", "chromium")
	}

	// Parse Local State for human-readable names. Failure is non-fatal.
	names := make(map[string]string)
	lsPath := filepath.Join(userDataDir, "Local State")
	if data, err := os.ReadFile(lsPath); err == nil {
		var ls localState
		if json.Unmarshal(data, &ls) == nil {
			for dir, info := range ls.Profile.InfoCache {
				names[dir] = info.Name
			}
		}
	}

	entries, err := os.ReadDir(userDataDir)
	if err != nil {
		return nil, err
	}

	var profiles []ChromeProfile
	for _, e := range entries {
		if !e.IsDir() {
			continue
		}
		dir := e.Name()
		if dir == "System Profile" {
			continue
		}

		prefPath := filepath.Join(userDataDir, dir, "Preferences")
		info, err := os.Stat(prefPath)
		if err != nil || info.IsDir() {
			continue
		}

		// Count extension directories (excluding "Temp").
		extCount := 0
		extDir := filepath.Join(userDataDir, dir, "Extensions")
		if exts, err := os.ReadDir(extDir); err == nil {
			for _, ext := range exts {
				if ext.IsDir() && ext.Name() != "Temp" {
					extCount++
				}
			}
		}

		name := names[dir]
		if name == "" {
			name = dir
		}

		profiles = append(profiles, ChromeProfile{
			Dir:            dir,
			Name:           name,
			Extensions:     extCount,
			HasPreferences: true,
		})
	}

	sort.Slice(profiles, func(i, j int) bool {
		return profiles[i].Dir < profiles[j].Dir
	})

	return profiles, nil
}