// Package config loads geniusrund's runtime infrastructure configuration
// from environment variables (paths and process settings that don't belong
// in the user-editable profile). Garmin credentials and every tunable
// analysis-engine parameter live in the profile (internal/store.Profile)
// instead -- see docs/superpowers/specs/2026-07-17-profile-taxonomy-analysis-engine-design.md.
package config

import (
	"fmt"
	"os"
	"strconv"
	"time"
)

// Config holds geniusrund's process-level configuration.
type Config struct {
	// Addr is the HTTP listen address, e.g. ":8080".
	Addr string
	// DBPath is the SQLite database file path.
	DBPath string

	// GarminPythonPath is mcp-garmin's venv python executable.
	GarminPythonPath string
	// GarminServerPath is mcp-garmin's server.py.
	GarminServerPath string
	// GarminTokenStore, if set, overrides mcp-garmin's default ~/.garth
	// session cache location.
	GarminTokenStore string

	MinConfidence        float64
	IncrementalSyncEvery time.Duration
}

// Load reads configuration from environment variables, applying defaults
// for anything optional. Returns an error if a required variable is unset.
func Load() (Config, error) {
	cfg := Config{
		Addr:                 getEnvDefault("GENIUSRUN_ADDR", ":8080"),
		DBPath:               getEnvDefault("GENIUSRUN_DB_PATH", "geniusrun.db"),
		GarminPythonPath:     os.Getenv("MCP_GARMIN_PYTHON"),
		GarminServerPath:     os.Getenv("MCP_GARMIN_SERVER"),
		GarminTokenStore:     os.Getenv("GARMIN_TOKENSTORE"),
		MinConfidence:        getEnvFloat("GENIUSRUN_MIN_CONFIDENCE", 0.6),
		IncrementalSyncEvery: getEnvDuration("GENIUSRUN_INCREMENTAL_SYNC_EVERY", 6*time.Hour),
	}

	if cfg.GarminPythonPath == "" {
		return cfg, fmt.Errorf("MCP_GARMIN_PYTHON is required (path to mcp-garmin's venv python)")
	}
	if cfg.GarminServerPath == "" {
		return cfg, fmt.Errorf("MCP_GARMIN_SERVER is required (path to mcp-garmin's server.py)")
	}
	return cfg, nil
}

func getEnvDefault(key, def string) string {
	if v := os.Getenv(key); v != "" {
		return v
	}
	return def
}

func getEnvFloat(key string, def float64) float64 {
	if v := os.Getenv(key); v != "" {
		if f, err := strconv.ParseFloat(v, 64); err == nil {
			return f
		}
	}
	return def
}

func getEnvDuration(key string, def time.Duration) time.Duration {
	if v := os.Getenv(key); v != "" {
		if d, err := time.ParseDuration(v); err == nil {
			return d
		}
	}
	return def
}