package config

import (
    "io"
    "os"
    "path/filepath"
    "strings"
    "gopkg.in/yaml.v3"
)

type DB struct {
    Host     string `yaml:"host"`
    Port     string `yaml:"port"`
    User     string `yaml:"user"`
    Password string `yaml:"password"`
    Name     string `yaml:"name"`
}

type App struct {
    Port        string `yaml:"port"`
    MarketingDB DB     `yaml:"marketing_db"`
    YMTDB       DB     `yaml:"ymt_db"`
}

type root struct {
    App App `yaml:"app"`
}

func Load() App {
    paths := []string{
        "config.yaml",
        filepath.Join("server", "config.yaml"),
    }
    var cfg App
    for _, p := range paths {
        if readYAML(p, &cfg) {
            break
        }
    }
    LoadEnv()
    if v := os.Getenv("MARKETING_DB_HOST"); v != "" { cfg.MarketingDB.Host = v }
    if v := os.Getenv("MARKETING_DB_PORT"); v != "" { cfg.MarketingDB.Port = v }
    if v := os.Getenv("MARKETING_DB_USER"); v != "" { cfg.MarketingDB.User = v }
    if v := os.Getenv("MARKETING_DB_PASSWORD"); v != "" { cfg.MarketingDB.Password = v }
    if v := os.Getenv("MARKETING_DB_NAME"); v != "" { cfg.MarketingDB.Name = v }
    if v := os.Getenv("YMT_DB_HOST"); v != "" { cfg.YMTDB.Host = v }
    if v := os.Getenv("YMT_DB_PORT"); v != "" { cfg.YMTDB.Port = v }
    if v := os.Getenv("YMT_DB_USER"); v != "" { cfg.YMTDB.User = v }
    if v := os.Getenv("YMT_DB_PASSWORD"); v != "" { cfg.YMTDB.Password = v }
    if v := os.Getenv("YMT_DB_NAME"); v != "" { cfg.YMTDB.Name = v }
    return cfg
}

func readYAML(path string, out *App) bool {
    f, err := os.Open(path)
    if err != nil {
        return false
    }
    defer f.Close()
    b, err := io.ReadAll(f)
    if err != nil {
        return false
    }
    var r root
    if err := yaml.Unmarshal(b, &r); err == nil {
        if r.App.Port != "" || r.App.MarketingDB.Host != "" || r.App.YMTDB.Host != "" {
            *out = r.App
            return true
        }
    }
    if err := yaml.Unmarshal(b, out); err != nil {
        return false
    }
    return true
}

func (d DB) DSN() string {
    if strings.TrimSpace(d.User) == "" || strings.TrimSpace(d.Host) == "" || strings.TrimSpace(d.Port) == "" || strings.TrimSpace(d.Name) == "" {
        return ""
    }
    return d.User + ":" + d.Password + "@tcp(" + d.Host + ":" + d.Port + ")/" + d.Name + "?parseTime=True&loc=Local&charset=utf8mb4"
}