package config

import (
	"fmt"
	"net/url"
	"strings"
	"time"
)

// Validate checks resolved configuration for required fields and parseable durations.
func Validate(cfg *Config) error {
	if cfg == nil {
		return fmt.Errorf("config is nil")
	}
	if cfg.Pipeline == nil {
		return fmt.Errorf("pipeline config is required")
	}
	if cfg.Session == nil {
		return fmt.Errorf("session config is required")
	}

	if err := validatePipeline(cfg.Pipeline); err != nil {
		return fmt.Errorf("pipeline config %q invalid: %w", shortName(cfg.PipelinePath, "pipeline.yml"), err)
	}
	if err := validateSession(cfg.Session); err != nil {
		return fmt.Errorf("session config %q invalid: %w", shortName(cfg.SessionPath, "session.yml"), err)
	}

	return nil
}

func validatePipeline(cfg *PipelineConfig) error {
	if strings.TrimSpace(cfg.Workspace.Root) == "" {
		return fmt.Errorf("pipeline.workspace.root is required")
	}
	if err := validateWhisperX(cfg.WhisperX); err != nil {
		return err
	}

	if err := validateDuration("pipeline.seriatim.timeout", cfg.Seriatim.Timeout); err != nil {
		return err
	}
	if err := validateDuration("pipeline.audita.timeout", cfg.Audita.Timeout); err != nil {
		return err
	}
	if err := validateDuration("pipeline.analyzer.timeout", cfg.Analyzer.Timeout); err != nil {
		return err
	}
	if err := validateDuration("pipeline.notification.timeout", cfg.Notification.Timeout); err != nil {
		return err
	}

	return nil
}

func validateWhisperX(cfg WhisperXConfig) error {
	if strings.TrimSpace(cfg.TranscribeURL) == "" {
		return fmt.Errorf("pipeline.whisperx.transcribe_url is required")
	}
	u, err := url.Parse(cfg.TranscribeURL)
	if err != nil || u.Scheme == "" || u.Host == "" {
		if err != nil {
			return fmt.Errorf("pipeline.whisperx.transcribe_url must be a valid URL: %w", err)
		}
		return fmt.Errorf("pipeline.whisperx.transcribe_url must be a valid URL")
	}
	if err := validateDuration("pipeline.whisperx.timeout", cfg.Timeout); err != nil {
		return err
	}
	if err := validateDuration("pipeline.whisperx.retry_delay", cfg.RetryDelay); err != nil {
		return err
	}
	if cfg.Retries == nil {
		return fmt.Errorf("pipeline.whisperx.retries must be set (defaults should populate this)")
	}
	if *cfg.Retries < 0 {
		return fmt.Errorf("pipeline.whisperx.retries must be >= 0")
	}
	if cfg.Concurrency == nil {
		return fmt.Errorf("pipeline.whisperx.concurrency must be set (defaults should populate this)")
	}
	if *cfg.Concurrency <= 0 {
		return fmt.Errorf("pipeline.whisperx.concurrency must be > 0")
	}
	return nil
}

func validateSession(cfg *SessionConfig) error {
	if strings.TrimSpace(cfg.SessionID) == "" {
		return fmt.Errorf("session.session_id is required")
	}

	if strings.TrimSpace(cfg.Inputs.SpeakersFile) == "" {
		return fmt.Errorf("session.inputs.speakers_file is required")
	}
	if strings.TrimSpace(cfg.Inputs.AutocorrectFile) == "" {
		return fmt.Errorf("session.inputs.autocorrect_file is required")
	}
	if strings.TrimSpace(cfg.Inputs.GlossaryFile) == "" {
		return fmt.Errorf("session.inputs.glossary_file is required")
	}

	hasAudioDir := strings.TrimSpace(cfg.Inputs.AudioDir) != ""
	hasAudioFiles := len(cfg.Inputs.AudioFiles) > 0
	if !hasAudioDir && !hasAudioFiles {
		return fmt.Errorf("session.inputs requires audio_dir or at least one audio_files entry")
	}

	return nil
}

func validateDuration(fieldName, value string) error {
	trimmed := strings.TrimSpace(value)
	if trimmed == "" {
		return nil
	}

	if _, err := time.ParseDuration(trimmed); err != nil {
		return fmt.Errorf("%s must be a valid duration: %w", fieldName, err)
	}

	return nil
}