package config

import (
	"errors"
	"fmt"
	"io/fs"
	"os"
	"path/filepath"
	"strings"
)

const AppsDir = "apps.d"

const maxAppsFile = 1 << 20

func readAppsDir(configPath string, cfg *Config) []Problem {
	dir := filepath.Join(filepath.Dir(configPath), AppsDir)
	entries, err := os.ReadDir(dir)
	if errors.Is(err, fs.ErrNotExist) {
		return nil
	}
	if err != nil {
		return []Problem{{File: dir, Reason: reasonUnreadable}}
	}
	used := map[string]bool{cfg.Server.DomainIDP: true, cfg.Server.DomainAccount: true, cfg.Server.DomainAdmin: true}
	for _, a := range cfg.Apps {
		used[a.Domain] = true
	}
	var problems []Problem
	for _, e := range entries {
		if e.IsDir() || !strings.HasSuffix(e.Name(), ".toml") {
			continue
		}
		file := filepath.Join(dir, e.Name())
		if cfg.Source == sourceGit {
			problems = append(problems, Problem{File: file, Reason: reasonAppsUnderGit})
			continue
		}
		data, reason := readRegular(file, maxAppsFile, reasonAppsTooLarge, nil)
		if reason != "" {
			problems = append(problems, Problem{File: file, Reason: reason})
			continue
		}
		idx, keyProblems := indexKeys(file, data)
		problems = append(problems, keyProblems...)
		if idx == nil {
			continue
		}
		others := map[string]bool{}
		for path := range idx.present {
			if top, _, _ := strings.Cut(path, "."); !strings.HasPrefix(top, "app[") && top != "app" && !others[top] {
				problems = append(problems, Problem{File: file, Line: idx.line(top), Key: top, Reason: reasonAppsOnly})
				others[top] = true
			}
		}
		raw, typed := decodeTyped(file, data, idx, keyProblems)
		problems = append(problems, typed...)
		if raw == nil || len(others) > 0 || len(keyProblems) > 0 {
			continue
		}
		v := &validator{file: file, idx: idx}
		for i, a := range raw.App {
			prefix := fmt.Sprintf("app[%d]", i)
			app := v.app(prefix, a, cfg.Session.TTL)
			if a.Domain != "" && used[a.Domain] {
				v.add(prefix+".domain", reasonDomainReused)
			}
			used[a.Domain] = true
			cfg.Apps = append(cfg.Apps, app)
		}
		problems = append(problems, v.problems...)
	}
	return problems
}