package config

import (
	"fmt"
	"os"

	"gopkg.in/yaml.v3"
)

type Config struct {
	Port         int             `yaml:"port"`
	APIKeys      []string        `yaml:"api_keys"`
	ClaudeBinary string          `yaml:"claude_binary"`
	Sanitize     SanitizeConfig  `yaml:"sanitize"`
	Logging      LoggingConfig   `yaml:"logging"`
	Telemetry    TelemetryConfig `yaml:"telemetry"`
}

type SanitizeConfig struct {
	Tools  []RenameRule  `yaml:"tools"`
	System []ReplaceRule `yaml:"system"`
	Body   []ReplaceRule `yaml:"body"`
}

type RenameRule struct {
	From string `yaml:"from"`
	To   string `yaml:"to"`
}

type ReplaceRule struct {
	Match   string `yaml:"match"`
	Replace string `yaml:"replace"`
}

type TelemetryConfig struct {
	Export      ExportConfig   `yaml:"export"`
	Embedded    EmbeddedConfig `yaml:"embedded"`
	ServiceName string         `yaml:"service_name"`
}

type ExportConfig struct {
	Endpoint string            `yaml:"endpoint"`
	Insecure bool              `yaml:"insecure"`
	Headers  map[string]string `yaml:"headers"`
}

func (e ExportConfig) Enabled() bool { return e.Endpoint != "" }

type EmbeddedConfig struct {
	Enabled      bool   `yaml:"enabled"`
	Port         int    `yaml:"port"`
	PersesBinary string `yaml:"perses_binary"`
	VMBinary     string `yaml:"vm_binary"`
	VMPort       int    `yaml:"vm_port"`
	BinDir       string `yaml:"bin_dir"`
}

type LoggingConfig struct {
	Level      string `yaml:"level"`
	File       string `yaml:"file"`
	MaxSizeMB  int    `yaml:"max_size_mb"`
	MaxBackups int    `yaml:"max_backups"`
	MaxAgeDays int    `yaml:"max_age_days"`
	Compress   bool   `yaml:"compress"`
}

func Load(path string) (*Config, error) {
	data, err := os.ReadFile(path)
	if err != nil {
		return nil, fmt.Errorf("read config %s: %w", path, err)
	}

	cfg := &Config{Port: 8080}
	if err := yaml.Unmarshal(data, cfg); err != nil {
		return nil, fmt.Errorf("parse config: %w", err)
	}

	if cfg.Logging.Level == "" {
		cfg.Logging.Level = "info"
	}
	if cfg.Logging.MaxSizeMB == 0 {
		cfg.Logging.MaxSizeMB = 100
	}
	if cfg.Logging.MaxBackups == 0 {
		cfg.Logging.MaxBackups = 5
	}
	if cfg.Logging.MaxAgeDays == 0 {
		cfg.Logging.MaxAgeDays = 30
	}

	if cfg.Telemetry.ServiceName == "" {
		cfg.Telemetry.ServiceName = "anthropic-proxy"
	}
	if cfg.Telemetry.Embedded.Port == 0 {
		cfg.Telemetry.Embedded.Port = 8080
	}
	if cfg.Telemetry.Embedded.PersesBinary == "" {
		cfg.Telemetry.Embedded.PersesBinary = "perses"
	}
	if cfg.Telemetry.Embedded.VMBinary == "" {
		cfg.Telemetry.Embedded.VMBinary = "victoria-metrics"
	}
	if cfg.Telemetry.Embedded.VMPort == 0 {
		cfg.Telemetry.Embedded.VMPort = 8428
	}

	// Check for deprecated claude_credentials field
	var rawCfg map[string]interface{}
	if err := yaml.Unmarshal(data, &rawCfg); err == nil {
		if _, exists := rawCfg["claude_credentials"]; exists {
			if val, ok := rawCfg["claude_credentials"].(string); ok && val != "" {
				return nil, fmt.Errorf("claude_credentials is no longer supported, remove it from config.yaml — the proxy now manages credentials at ~/.claude/.credentials.json")
			}
		}
	}

	return cfg, nil
}